DEPARTMENT OF NATIONAL RESOURCES

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

BULLETIN 166

Geology of the Surat Basinin Queensland

N. F. EXON

AUSTRALIAN GOVERNMENT PUBLISHING SERVICE

CANBERRA, 1976

DEPARTMENT OF NATIONAL RESOURCES

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

BULLETIN 166

Geology of the Surat Basinin Queensland

N. F. EXON

AUSTRALIAN GOVERNMENT PUBLISHING SERVICE

CANBERRA, 1976

DEPARTMENT OF NATIONAL RESOURCES

MINISTER: THE RT HON. 1. D. ANTHONY, M.P.

SECRETARY: J. SCULLY

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

DIRECTOR: L. C. NOAKES

ASSISTANT DIRECTOR, GEOLOGICAL BRANCH: J. N. CASEY

ABSTRACTThe Surat Basin of eastern Australia contains 2500 m of Jurassic and Cretaceous sedi­

ments, terrestrial during the Jurassic, but showing two marine incursions during the EarlyCretaceous. The sequence is almost flat-lying; the gentle basinward dip is modified by a fewdrape or compaction folds and faults. Deposition during the Jurassic was dominantly fluviatileand consisted of fining-upward megacycles, each more than 100 m thick. Volcanic debris sug­gests contemporaneous volcanism in both the Jurassic and the Early Cretaceous.

Sedimentation gave way to erosion during the Late Cretaceous and Early Tertiary, and therocks were deeply weathered. In the Oligocene and Miocene, basin volcanicity around themargins of the Basin accompanied epeirogenic basinward tilting; since then the basin has beenstable.

Petroleum reserves in the basin in 1974 were estimated as 51 billion m3 of gas and 31million m3 of oil. The Walloon Coal Measures hold considerable reserves of bituminous coaland some of oil shale.

Published for the Bureau of Mineral Resources, Geology and Geophysicsby The Australian Government Publishing Service

ISBN 0 642 01947 9

MANUSCRIPT RECEIVED: FEBRUARY, 1974

REVISED MANUSCRIPT RECEIVED: DECEMBER 1974

ISSUED: AUGUST 1976

Printed by Graphic Services Pty Ltd, 516-518 Grand Junction Road, Northfield S.A. 5085

DEPARTMENT OF NATIONAL RESOURCES

MINISTER: THE RT HON. 1. D. ANTHONY, M.P.

SECRETARY: J. SCULLY

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

DIRECTOR: L. C. NOAKES

ASSISTANT DIRECTOR, GEOLOGICAL BRANCH: J. N. CASEY

ABSTRACTThe Surat Basin of eastern Australia contains 2500 m of Jurassic and Cretaceous sedi­

ments, terrestrial during the Jurassic, but showing two marine incursions during the EarlyCretaceous. The sequence is almost flat-lying; the gentle basinward dip is modified by a fewdrape or compaction folds and faults. Deposition during the Jurassic was dominantly fluviatileand consisted of fining-upward megacycles, each more than 100 m thick. Volcanic debris sug­gests contemporaneous volcanism in both the Jurassic and the Early Cretaceous.

Sedimentation gave way to erosion during the Late Cretaceous and Early Tertiary, and therocks were deeply weathered. In the Oligocene and Miocene, basin volcanicity around themargins of the Basin accompanied epeirogenic basinward tilting; since then the basin has beenstable.

Petroleum reserves in the basin in 1974 were estimated as 51 billion m3 of gas and 31million m3 of oil. The Walloon Coal Measures hold considerable reserves of bituminous coaland some of oil shale.

Published for the Bureau of Mineral Resources, Geology and Geophysicsby The Australian Government Publishing Service

ISBN 0 642 01947 9

MANUSCRIPT RECEIVED: FEBRUARY, 1974

REVISED MANUSCRIPT RECEIVED: DECEMBER 1974

ISSUED: AUGUST 1976

Printed by Graphic Services Pty Ltd, 516-518 Grand Junction Road, Northfield S.A. 5085

CONTENTS

SUMMARYINTRODUCTION

PhysiographyGeological investigations

Surface geologyPalaeontologyPetroleum search

The present studyAcknowledgementsLithological nomenclature

STRUCTUREGEOLOGICAL EVOLUTION

Bowen BasinSurat Basin

PETROLEUM GEOLOGYSource rocksMigration and entrapmentRoma Shelf accumulationsMoonie Oil FieldAlton Oil FieldThe Bollon area ...Conclusions

ECONOMIC GEOLOGY (excluding petroleum)GroundwaterSurface waterCoalBentoniteIron oreRoad metal and aggregateClayMiscellaneous minerals

ROCK UNITS OLDER THAN THE SURAT BASINPre-Bowen Basin basement

Timbury Hills Formation'Kuttung Formation' and equivalentsRoma granitesAuburn ComplexYarraman ComplexTexas High granitesOther igneous bodies .

Bowen Basin rocksPermian sequence north of Surat BasinPermian sequence on Roma Shelf

Reids Dome BedsBack Creek GroupBlackwater Group

Permian sequence in Taroom Trough beneath Surat BasinBack Creek GroupBlackwater Group

Lower Triassic Bowen Basin sequenceRewan GroupCabawin Formation

Middle Triassic Bowen Basin sequenceClematis GroupMoolayember FormationWandoan Formation

Triassic and Jurassic Rocks confined to Ipswich-Moreton BasinRegional settingTriassic volcanics

iii

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1010121414142525384345475254555758

595961616263636465

6666666666666669696969737374747474757575777878787980

..8080

CONTENTS

SUMMARYINTRODUCTION

PhysiographyGeological investigations

Surface geologyPalaeontologyPetroleum search

The present studyAcknowledgementsLithological nomenclature

STRUCTUREGEOLOGICAL EVOLUTION

Bowen BasinSurat Basin

PETROLEUM GEOLOGYSource rocksMigration and entrapmentRoma Shelf accumulationsMoonie Oil FieldAlton Oil FieldThe Bollon area ...Conclusions

ECONOMIC GEOLOGY (excluding petroleum)GroundwaterSurface waterCoalBentoniteIron oreRoad metal and aggregateClayMiscellaneous minerals

ROCK UNITS OLDER THAN THE SURAT BASINPre-Bowen Basin basement

Timbury Hills Formation'Kuttung Formation' and equivalentsRoma granitesAuburn ComplexYarraman ComplexTexas High granitesOther igneous bodies .

Bowen Basin rocksPermian sequence north of Surat BasinPermian sequence on Roma Shelf

Reids Dome BedsBack Creek GroupBlackwater Group

Permian sequence in Taroom Trough beneath Surat BasinBack Creek GroupBlackwater Group

Lower Triassic Bowen Basin sequenceRewan GroupCabawin Formation

Middle Triassic Bowen Basin sequenceClematis GroupMoolayember FormationWandoan Formation

Triassic and Jurassic Rocks confined to Ipswich-Moreton BasinRegional settingTriassic volcanics

iii

Page13699

1010121414142525384345475254555758

595961616263636465

6666666666666669696969737374747474757575777878787980

..8080

iv

PageAberdare Conglomerate 80Raceview Formation 82Helidon Sandstone 82Marburg Sandstone 83

SURAT BASIN ROCK UNITS 85Dominantly non-marine Jurassic to lowermost Cretaceous sequence 85

Precipice Sandstone 85Evergreen Formation 90Hutton Sandstone 92Injune Creek Group 93Eurombah Formation 93Walloon Coal Measures 94Birkhead Formation 95Springbok Sandstone 95Adori Sandstone 97Westbourne Formation 97PilIiga Sandstone 98Gubberamunda Sandstone 99Orallo Formation 102Mooga Sandstone 105Hooray Sandstone 106Kumbarilla Beds 110

Dominantly Marine Lower Cretaceous Sequence 110Bungil Formation 110Doncaster Member (Wallumbilla Formation) 115Coreena Member (Wallumbilla Formation) 119Surat Siltstone 120Griman Creek Formation 121

CAINOZOIC ROCKS 122Gabbro 122Basalt 124Cainozoic sediments 124

WEATHERING PHENOMENA 127Tertiary deep weathering 128Silcrete 129Recent weathering 130

REFERENCES 131

APPENDICES1. Aptian and Albian macrofossils from the Mitchell and Roma 1:250000 Sheet

areas, by R. W. Day 1372. Notes on the vertebrate fauna of the Chinchilla Sand, by A. Bartholomai and

J. T. Woods 1513. Notes on the fossiliferous Pleistocene f1uviatile deposits of the eastern Darling

Downs, by A. Bartholomai 1534. Clay minerals of the Middle Jurassic to Lower Cretaceous sequence, by N. F. Exon 1555. BMR Record 1974/113-Wireline-logging of water-bores in the Surat Basin, 1960

to 1974, by N. F. Exon and J. Mbrrissey (in pocket at back of Bulletin)

TABLES1. Relevant Petroleum Search Subsidy Acts Publications 112. Relevant Union Oil Development Corporation unpublished geological reports 123. Source of geophysical data used for structure contour maps .... 134. General stratigraphy data used for structure contour maps . 245. Proved gas reserves, Surat Basin 446. Proved oil reserves, Surat Basin 457. Geothermal gradients and depth of potential hydrocarbon production 468. Gas shows in Permian sequence south of latitude 24° 30'S . 589. Oil shows in Permian sequence south of latitude 24°30'S 58

10. Chemistry of major aquifers 6111. Pre-Bowen Basin stratigraphy 67

J

iv

PageAberdare Conglomerate 80Raceview Formation 82Helidon Sandstone 82Marburg Sandstone 83

SURAT BASIN ROCK UNITS 85Dominantly non-marine Jurassic to lowermost Cretaceous sequence 85

Precipice Sandstone 85Evergreen Formation 90Hutton Sandstone 92Injune Creek Group 93Eurombah Formation 93Walloon Coal Measures 94Birkhead Formation 95Springbok Sandstone 95Adori Sandstone 97Westbourne Formation 97PilIiga Sandstone 98Gubberamunda Sandstone 99Orallo Formation 102Mooga Sandstone 105Hooray Sandstone 106Kumbarilla Beds 110

Dominantly Marine Lower Cretaceous Sequence 110Bungil Formation 110Doncaster Member (Wallumbilla Formation) 115Coreena Member (Wallumbilla Formation) 119Surat Siltstone 120Griman Creek Formation 121

CAINOZOIC ROCKS 122Gabbro 122Basalt 124Cainozoic sediments 124

WEATHERING PHENOMENA 127Tertiary deep weathering 128Silcrete 129Recent weathering 130

REFERENCES 131

APPENDICES1. Aptian and Albian macrofossils from the Mitchell and Roma 1:250000 Sheet

areas, by R. W. Day 1372. Notes on the vertebrate fauna of the Chinchilla Sand, by A. Bartholomai and

J. T. Woods 1513. Notes on the fossiliferous Pleistocene f1uviatile deposits of the eastern Darling

Downs, by A. Bartholomai 1534. Clay minerals of the Middle Jurassic to Lower Cretaceous sequence, by N. F. Exon 1555. BMR Record 1974/113-Wireline-logging of water-bores in the Surat Basin, 1960

to 1974, by N. F. Exon and J. Mbrrissey (in pocket at back of Bulletin)

TABLES1. Relevant Petroleum Search Subsidy Acts Publications 112. Relevant Union Oil Development Corporation unpublished geological reports 123. Source of geophysical data used for structure contour maps .... 134. General stratigraphy data used for structure contour maps . 245. Proved gas reserves, Surat Basin 446. Proved oil reserves, Surat Basin 457. Geothermal gradients and depth of potential hydrocarbon production 468. Gas shows in Permian sequence south of latitude 24° 30'S . 589. Oil shows in Permian sequence south of latitude 24°30'S 58

10. Chemistry of major aquifers 6111. Pre-Bowen Basin stratigraphy 67

J

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123

v

12. Pre-Bowen Basin igneous and metamorphic rocks13. Nomenclature and correlates, southern part of Bowen Basin14. Permian stratigraphy, Bowen Basin15. Maximum rates of sediment accumulation for various stratigraphic intervals16. Permian stratigraphy, Roma Shelf17. Triassic stratigraphy, Bowen and Ipswich-Moreton Basins18. Jurassic-Cretaceous nomenclature in Surat and adjacent basins19. Dominantly non-marine Jurassic to Lower Cretaceous sequence20. Marine Cretaceous stratigraphy21. Cainozoic igneous rocks and sediments

ILLUSTRAnONSFIGURES

I. Regional setting 3,42. Towns and access 53. Topography and drainage 74. Physiographic units 85. Solid geology 156. Structural elements 167. Structure contours, top of basement 188. Structure contours, top of Permian sequence 199. Structure contours, top of Evergreen Formation 20

10. Structure contours, top of Walloon Coal Measures 2111. Structure contours, top of Mooga and Hooray Sandstones 2212. Structure contours, top of Doncaster Member 2313. Thickness of Permian sequence 2614. Thickness of Blackwater Group 2715. Thickness of Rewan Group and Cabawin Formation 2816. Thickness of Wandoan Formation 2917. Units immediately below the Surat Basin 3118. Units immediately above the pre-Jurassic unconformity 3219. Thickness of Precipice Sandstone and Evergreen Formation 3320. Thickness of lower part of Precipice Sandstone 3421. Thickness of Hutton Sandstone and Walloon Coal Measures 3522. Thickness of Westbourne Formation and Springbok Sandstone 3623. Thickness of Gubberamunda Sandstone/Mooga Sandstone interval 3724. Cross-sections showing evolution of Bowen and Surat Basins 3825. Thickness of Bungil Formation and Doncaster Member 3926. Thickness of marine Cretaceous sequence 4027. Petroleum migration routes 4828. Petroleum fields on Roma Shelf 5129. Structure map of Moonie Oil Field 5330. Cross-section through Moonie Oil Field 5431. Structure of Alton Oil Field 5632. Distribution of aquifers ... 6033. Thick bed of bentonite in Orallo Formation .,. 6334. Close-up photograph of bentonite in OralIo Formation 6435. Cross-bedding in Springbok Sandstone 9636. Interbedded sandstone and siltstone of Gubberamunda Sandstone 10037. Gubberamunda Sandstone unconformably overlying Westbourne Formation 10138. Trough cross-bedding in sandstone of Orallo Formation 10239. Calcareous concretions in sandstone of Orallo Formation 10340. Fossil tree stump in Orallo Formation 10441. Planar cross-bedding in Mooga Sandstone 10542. Trough cross-bedding in Kingull Member III43. Well bedded sandstone in an equivalent of KingulI Member 11244. Ripple marks, cross-lamination, and carbonaceous partings in an equivalent of

Kingull Member 11345. Infilled desiccation cracks in Nullawurt Sandstone Member. 11446. Distribution of Cretaceous foraminifera 11847. Columnar basalt of Tertiary age near Jimbour 12548. Distribution and thickness of Cainozoic sequence 12649. Deep-weathering profile developed on Coreena Member 128

Page68707172737681

86-89108-109

123

v

12. Pre-Bowen Basin igneous and metamorphic rocks13. Nomenclature and correlates, southern part of Bowen Basin14. Permian stratigraphy, Bowen Basin15. Maximum rates of sediment accumulation for various stratigraphic intervals16. Permian stratigraphy, Roma Shelf17. Triassic stratigraphy, Bowen and Ipswich-Moreton Basins18. Jurassic-Cretaceous nomenclature in Surat and adjacent basins19. Dominantly non-marine Jurassic to Lower Cretaceous sequence20. Marine Cretaceous stratigraphy21. Cainozoic igneous rocks and sediments

ILLUSTRAnONSFIGURES

I. Regional setting 3,42. Towns and access 53. Topography and drainage 74. Physiographic units 85. Solid geology 156. Structural elements 167. Structure contours, top of basement 188. Structure contours, top of Permian sequence 199. Structure contours, top of Evergreen Formation 20

10. Structure contours, top of Walloon Coal Measures 2111. Structure contours, top of Mooga and Hooray Sandstones 2212. Structure contours, top of Doncaster Member 2313. Thickness of Permian sequence 2614. Thickness of Blackwater Group 2715. Thickness of Rewan Group and Cabawin Formation 2816. Thickness of Wandoan Formation 2917. Units immediately below the Surat Basin 3118. Units immediately above the pre-Jurassic unconformity 3219. Thickness of Precipice Sandstone and Evergreen Formation 3320. Thickness of lower part of Precipice Sandstone 3421. Thickness of Hutton Sandstone and Walloon Coal Measures 3522. Thickness of Westbourne Formation and Springbok Sandstone 3623. Thickness of Gubberamunda Sandstone/Mooga Sandstone interval 3724. Cross-sections showing evolution of Bowen and Surat Basins 3825. Thickness of Bungil Formation and Doncaster Member 3926. Thickness of marine Cretaceous sequence 4027. Petroleum migration routes 4828. Petroleum fields on Roma Shelf 5129. Structure map of Moonie Oil Field 5330. Cross-section through Moonie Oil Field 5431. Structure of Alton Oil Field 5632. Distribution of aquifers ... 6033. Thick bed of bentonite in Orallo Formation .,. 6334. Close-up photograph of bentonite in OralIo Formation 6435. Cross-bedding in Springbok Sandstone 9636. Interbedded sandstone and siltstone of Gubberamunda Sandstone 10037. Gubberamunda Sandstone unconformably overlying Westbourne Formation 10138. Trough cross-bedding in sandstone of Orallo Formation 10239. Calcareous concretions in sandstone of Orallo Formation 10340. Fossil tree stump in Orallo Formation 10441. Planar cross-bedding in Mooga Sandstone 10542. Trough cross-bedding in Kingull Member III43. Well bedded sandstone in an equivalent of KingulI Member 11244. Ripple marks, cross-lamination, and carbonaceous partings in an equivalent of

Kingull Member 11345. Infilled desiccation cracks in Nullawurt Sandstone Member. 11446. Distribution of Cretaceous foraminifera 11847. Columnar basalt of Tertiary age near Jimbour 12548. Distribution and thickness of Cainozoic sequence 12649. Deep-weathering profile developed on Coreena Member 128

vi

PLATES1A. Geology of the northern part of the Surat Basin (1: 1 000000)lB. Petroleum exploration wells and wireline-Iogged water-bores in the northern part

of the Surat Basin used as data points (I: 1 000 000)2. Well correlation diagram: Morven to Miles3. Well correlation diagram: Morven to Cecil Plains4. Well correlation diagram: Gunnewin to Boomi 15. Well correlation diagram: Wandoan to Boomi 16. Well correlation diagram: Wunger 1 to Whyenbirra 17. Well correlation diagram: Kinnimo 1 to Sand Camp I8. Correlation diagram of gamma-logged water bores: Roma to Moonie9. Structure contours, top of basement and basement rock types (I: 1 000 000)

10. Structure contours, top of Perrnian sequence (1: 1 000 000)11. Structure contours, top of Triassic sequence (1: 1 000000)12. Structure contours, top of Evergreen Formation (I: 1 000000)13. Structure contours, top of WalIoon Coal Measures (I: 1 000000)14. Structure contours, top of Mooga and Hooray Sandstones (I: 1 000000)15. Structure contours, top of Doncaster Member (I: 1 000000)16. Thickness of Precipice Sandstone and Evergreen Formation (I: 1000000)17. Thickness of Hutton Sandstone and Walloon Coal Measures (1:1000000)18. Thickness of Westbourne Formation and Springbok Sandstone (I: 1 000000)19. Thickness of Gubberamunda Sandstone/Mooga Sandstone interval (1: I 000000)20. Thickness of non-marine part of Surat Basin sequence (I: I 000000)21. Thickness of marine part of Surat Basin sequence (1: 1 000000)

I

I

II

J

vi

PLATES1A. Geology of the northern part of the Surat Basin (1: 1 000000)lB. Petroleum exploration wells and wireline-Iogged water-bores in the northern part

of the Surat Basin used as data points (I: 1 000 000)2. Well correlation diagram: Morven to Miles3. Well correlation diagram: Morven to Cecil Plains4. Well correlation diagram: Gunnewin to Boomi 15. Well correlation diagram: Wandoan to Boomi 16. Well correlation diagram: Wunger 1 to Whyenbirra 17. Well correlation diagram: Kinnimo 1 to Sand Camp I8. Correlation diagram of gamma-logged water bores: Roma to Moonie9. Structure contours, top of basement and basement rock types (I: 1 000 000)

10. Structure contours, top of Perrnian sequence (1: 1 000 000)11. Structure contours, top of Triassic sequence (1: 1 000000)12. Structure contours, top of Evergreen Formation (I: 1 000000)13. Structure contours, top of WalIoon Coal Measures (I: 1 000000)14. Structure contours, top of Mooga and Hooray Sandstones (I: 1 000000)15. Structure contours, top of Doncaster Member (I: 1 000000)16. Thickness of Precipice Sandstone and Evergreen Formation (I: 1000000)17. Thickness of Hutton Sandstone and Walloon Coal Measures (1:1000000)18. Thickness of Westbourne Formation and Springbok Sandstone (I: 1 000000)19. Thickness of Gubberamunda Sandstone/Mooga Sandstone interval (1: I 000000)20. Thickness of non-marine part of Surat Basin sequence (I: I 000000)21. Thickness of marine part of Surat Basin sequence (1: 1 000000)

I

I

II

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1

SUMMARYThe Jurassic-Cretaceous Surat Basin, which is elongated meridionally. covers 300000 km2 in eastern

Australia, mostly in Queensland. It contains up to 2500 m of virtually flat-lying sedimentary rocks andinterfingers westward across the Nebine Ridge with the Eromanga Basin, and eastward across the Kum­barilla Ridge with the Moreton Basin. Basement blocks consisting of the Central West Fold Belt and theNew England Fold Belt limit the basin to the south, and the South Coastal Structural High limits it tothe northeast. To the north the basin has been eroded. Dips seldom exceed 2 0

, and fault displacements ofmore than 200 m are rare.

The main part of the Permo-Triassic Bowen Basin, which covers in total an area of 200000 km2,

lies to the north of the Surat Basin, but a southerly extension, the southern part of the Taroom Trough,unconformably underlies the Surat Basin. The southern part of the trough has an area of 50000 km2 ,

and contains up to 9000 m of sedimentary rocks. The Taroom Trough is a meridional half-graben,bounded to the east by a line of faults along the margins of basement blocks. Dips seldom exceed 15 0

,

but fault displacements are as much as 2000 m. The structures in the Bowen Basin are generallyreflected in the overlying Surat Basin sequence.

In Early Permian time the marine Back Creek Group was laid down over most of the area, whichwas fairly flat except in the southwest, where basement was exposed until the Jurassic. In the Late Per­mian the sea withdrew and the coal measures of the Blackwater Group were deposited. The Permiansequence is over 3500 m thick in places.

In the Early Triassic the redbeds of the Rewan Group were laid down over much of the area. Inthe southeast the faults bounding the Taroom Trough had started to develop and the conglomeraticCabawin Formation was deposited nearby.

Late in the Early Triassic and in the Middle Triassic normal stream sediments accumulated in theTaroom Trough. Initially they were also laid down in the northeast, but the faults bounding the troughin the north developed during this period. The Triassic sequence (Rewan and Clematis Groups andMoolayember Formation in the north, Rewan Group and Wandoan Formation in the south) is up to5000 m thick.

Late Triassic erosion removed all the Triassic and most of the Permian sequence east of the faultzone. Important tectonic movements had ceased by the Jurassic, and most structures in the Surat Basinsequence are drapes over basement rises, and depressions due to the compaction of thick sedimentarysequences.

Deposition in the Surat Basin gradually extended, and even the basal sands extend beyond theTaroom Trough. The Jurassic to lowermost Cretaceous sediments are essentially terrestrial and cyclic;the sequence is up to 1700 m thick, and each of the five cycles is hundreds of metres thick. Each cyclegenerally began with the deposition of fairly coarse mature sand, which graded up into finer and morelabile sand and silt, and ended with the deposition of labile sand, silt, mud, and coal. The cycles repre­sent deposition by braided streams, followed by meandering streams, and finally by deposition in swamps,lakes, deltas and, in places, shallow seas. Andesitic volcanic debris is common in the Middle and UpperJurassic sequence; it represents, in part at least, contemporaneous volcanism. Late Jurassic epeirogenicuplift gave the basin its present general configurat ion.

The sea entered the area in the Neocomian, probably initially from the east and later across theNebine Ridge, and muds were being laid down below wave base by the late Aptian. There followed a.regression during which sand, silt, and mud were deposited, another transgression marked by silt andmud, and a final regression during which sand and silt were deposited. The two transgressive muddy unitsand two regressive sandy units together form the Rolling Downs Group, whose deposition ceased in thelate Albian. Andesitic debris derived from Early Cretaceous volcanism to the east is a major componentof the sequence. The combined thickness of the Rolling Downs Group and the previous paralic unit(Bungil Formation) is up to 1200 m.

Steady erosion and pediplanation took place during the Late Cretaceous and Early Tertiary, and adeep-weathering profile was developed. In Oligocene-Miocene time basic volcanics were poured outaround the Surat Basin and epeirogenic movements increased the basinward tilt. Thereafter the basinremained stable and its northern margin was extensively eroded.

By 1974 over 350 petroleum exploration wells had been drilled and over 30 gas fields and 2 signi­ficant oil fields discovered: the initial total reserves were estimated at 5463 million m3 of gas and3.608 million 013 of oil. Production is mainly from the basal Jurassic Precipice Sandstone. Gas and oilpipelines have been laid to Brisbane and the oil reserves have already been heavily depleted. Futureexploration will probably be concentrated on the Precipice Sandstone and the Permian sequence on andnear the Roma Shelf. Another target warranting consideration is the Jurassic Hutton Sandstone in theBollon area.

The Middle Jurassic Walloon Coal Measures could be open-cut for power generation and severalprospects are currently being assessed.

1

SUMMARYThe Jurassic-Cretaceous Surat Basin, which is elongated meridionally. covers 300000 km2 in eastern

Australia, mostly in Queensland. It contains up to 2500 m of virtually flat-lying sedimentary rocks andinterfingers westward across the Nebine Ridge with the Eromanga Basin, and eastward across the Kum­barilla Ridge with the Moreton Basin. Basement blocks consisting of the Central West Fold Belt and theNew England Fold Belt limit the basin to the south, and the South Coastal Structural High limits it tothe northeast. To the north the basin has been eroded. Dips seldom exceed 2 0

, and fault displacements ofmore than 200 m are rare.

The main part of the Permo-Triassic Bowen Basin, which covers in total an area of 200000 km2,

lies to the north of the Surat Basin, but a southerly extension, the southern part of the Taroom Trough,unconformably underlies the Surat Basin. The southern part of the trough has an area of 50000 km2 ,

and contains up to 9000 m of sedimentary rocks. The Taroom Trough is a meridional half-graben,bounded to the east by a line of faults along the margins of basement blocks. Dips seldom exceed 15 0

,

but fault displacements are as much as 2000 m. The structures in the Bowen Basin are generallyreflected in the overlying Surat Basin sequence.

In Early Permian time the marine Back Creek Group was laid down over most of the area, whichwas fairly flat except in the southwest, where basement was exposed until the Jurassic. In the Late Per­mian the sea withdrew and the coal measures of the Blackwater Group were deposited. The Permiansequence is over 3500 m thick in places.

In the Early Triassic the redbeds of the Rewan Group were laid down over much of the area. Inthe southeast the faults bounding the Taroom Trough had started to develop and the conglomeraticCabawin Formation was deposited nearby.

Late in the Early Triassic and in the Middle Triassic normal stream sediments accumulated in theTaroom Trough. Initially they were also laid down in the northeast, but the faults bounding the troughin the north developed during this period. The Triassic sequence (Rewan and Clematis Groups andMoolayember Formation in the north, Rewan Group and Wandoan Formation in the south) is up to5000 m thick.

Late Triassic erosion removed all the Triassic and most of the Permian sequence east of the faultzone. Important tectonic movements had ceased by the Jurassic, and most structures in the Surat Basinsequence are drapes over basement rises, and depressions due to the compaction of thick sedimentarysequences.

Deposition in the Surat Basin gradually extended, and even the basal sands extend beyond theTaroom Trough. The Jurassic to lowermost Cretaceous sediments are essentially terrestrial and cyclic;the sequence is up to 1700 m thick, and each of the five cycles is hundreds of metres thick. Each cyclegenerally began with the deposition of fairly coarse mature sand, which graded up into finer and morelabile sand and silt, and ended with the deposition of labile sand, silt, mud, and coal. The cycles repre­sent deposition by braided streams, followed by meandering streams, and finally by deposition in swamps,lakes, deltas and, in places, shallow seas. Andesitic volcanic debris is common in the Middle and UpperJurassic sequence; it represents, in part at least, contemporaneous volcanism. Late Jurassic epeirogenicuplift gave the basin its present general configurat ion.

The sea entered the area in the Neocomian, probably initially from the east and later across theNebine Ridge, and muds were being laid down below wave base by the late Aptian. There followed a.regression during which sand, silt, and mud were deposited, another transgression marked by silt andmud, and a final regression during which sand and silt were deposited. The two transgressive muddy unitsand two regressive sandy units together form the Rolling Downs Group, whose deposition ceased in thelate Albian. Andesitic debris derived from Early Cretaceous volcanism to the east is a major componentof the sequence. The combined thickness of the Rolling Downs Group and the previous paralic unit(Bungil Formation) is up to 1200 m.

Steady erosion and pediplanation took place during the Late Cretaceous and Early Tertiary, and adeep-weathering profile was developed. In Oligocene-Miocene time basic volcanics were poured outaround the Surat Basin and epeirogenic movements increased the basinward tilt. Thereafter the basinremained stable and its northern margin was extensively eroded.

By 1974 over 350 petroleum exploration wells had been drilled and over 30 gas fields and 2 signi­ficant oil fields discovered: the initial total reserves were estimated at 5463 million m3 of gas and3.608 million 013 of oil. Production is mainly from the basal Jurassic Precipice Sandstone. Gas and oilpipelines have been laid to Brisbane and the oil reserves have already been heavily depleted. Futureexploration will probably be concentrated on the Precipice Sandstone and the Permian sequence on andnear the Roma Shelf. Another target warranting consideration is the Jurassic Hutton Sandstone in theBollon area.

The Middle Jurassic Walloon Coal Measures could be open-cut for power generation and severalprospects are currently being assessed.

3

INTRODUCTIONThe Surat Basin is about 300 000 km 2 in

area (Fig. 1); over half of it lies in Queens­land, the remainder in New South Wales. Itcontains up to 2500 m of mainly Jurassicclastic continental sedimentary rocks andLower Cretaceous marine beds. Dips aregenerally centripetal but low; the rocks inthe central part of the basin are extensivelyobscured by Cainozoic alluvium. Hydrocar-

bons are being produced from a number ofsmall fields, generally from reservoirs inLower Jurassic sandstones.

The main roads, railways, and centres ofpopulation in the area studied are shown inFigure 2, and the general topography andthe main drainage systems are outlined inFigure 3. The highest country is in the northand east (1000-300 m) and the lowest in

146°

- -- -: z- . iij- --

- -~.-. -. CD:· .. - -

.' ............. ....

......... " ...... . . .. .... ,',' ,', : ',' ...-:.: e-':-:---:-:

.................~·...·.. r··...·.·....

Great Artesian Basin(Jurassic- Cretaceous)

146° 152°

24°

26°

32°

O!A!564

Geological boundary

Fault

Gunnedah_ Bowen andGalilee Basins (Permo-Triassic)

J( lII: J\ If:ol )( 'Il; )(

)C )l ..)( Basement)( j( It lII.

)l.)C )()l

200

Basement ridge

30Glm

Fig. la. Regional setting.

3

INTRODUCTIONThe Surat Basin is about 300 000 km 2 in

area (Fig. 1); over half of it lies in Queens­land, the remainder in New South Wales. Itcontains up to 2500 m of mainly Jurassicclastic continental sedimentary rocks andLower Cretaceous marine beds. Dips aregenerally centripetal but low; the rocks inthe central part of the basin are extensivelyobscured by Cainozoic alluvium. Hydrocar-

bons are being produced from a number ofsmall fields, generally from reservoirs inLower Jurassic sandstones.

The main roads, railways, and centres ofpopulation in the area studied are shown inFigure 2, and the general topography andthe main drainage systems are outlined inFigure 3. The highest country is in the northand east (1000-300 m) and the lowest in

146°

- -- -: z- . iij- --

- -~.-. -. CD:· .. - -

.' ............. ....

......... " ...... . . .. .... ,',' ,', : ',' ...-:.: e-':-:---:-:

.................~·...·.. r··...·.·....

Great Artesian Basin(Jurassic- Cretaceous)

146° 152°

24°

26°

32°

O!A!564

Geological boundary

Fault

Gunnedah_ Bowen andGalilee Basins (Permo-Triassic)

J( lII: J\ If:ol )( 'Il; )(

)C )l ..)( Basement)( j( It lII.

)l.)C )()l

200

Basement ridge

30Glm

Fig. la. Regional setting.

32°

O/A!565

TAMWORTH•300 ~m

I200100

4

146" 148 0 1520

24"

---1I :<?;

I "":

I '"-l

I u

I I 0

I II II I qI I • GI BfllSBANE

I I 18°

IIL _____

NARRABRI

Gunnedah, Bowen andGalilee Basins (Permo-Triassic)

_ __ Boundary between outcropp;ng and

subcropping Permo- Triass;c sequence

Basement ~ Fault

Fig. lb. Regional setting.

the southwest (less than 200 m). Theeastern edge of the basin lies less than 200km from the Pacific coast, whereas the west­ern edge is 500 km inland. The climatethroughout the basin is subtropical, but thehigher country nearer the coast is muchcooler and wetter than the inland areas.

The annual average temperature variesacross the area from 15 °e to 21 °e and thenormal annual range is ooe to 35°C. Tem­peratures higher than 45°e and lower than

_5°e are uncommon. Frosts are commonduring winter nights. The annual rainfallranges from 800 mm in the east to 350 mmin the southwest and the average annualrunoff varies accordingly from 120 to lessthan 12.5 mm.

Drainage through virtually the entire area(Fig. 3) is to the southwest, joining the Dar­ling system, which debouches eventually intothe Southern Ocean. Gradients are initiallyhigh, but diminish rapidly to the southwest,

I

J

32°

O/A!565

TAMWORTH•300 ~m

I200100

4

146" 148 0 1520

24"

---1I :<?;

I "":

I '"-l

I u

I I 0

I II II I qI I • GI BfllSBANE

I I 18°

IIL _____

NARRABRI

Gunnedah, Bowen andGalilee Basins (Permo-Triassic)

_ __ Boundary between outcropp;ng and

subcropping Permo- Triass;c sequence

Basement ~ Fault

Fig. lb. Regional setting.

the southwest (less than 200 m). Theeastern edge of the basin lies less than 200km from the Pacific coast, whereas the west­ern edge is 500 km inland. The climatethroughout the basin is subtropical, but thehigher country nearer the coast is muchcooler and wetter than the inland areas.

The annual average temperature variesacross the area from 15 °e to 21 °e and thenormal annual range is ooe to 35°C. Tem­peratures higher than 45°e and lower than

_5°e are uncommon. Frosts are commonduring winter nights. The annual rainfallranges from 800 mm in the east to 350 mmin the southwest and the average annualrunoff varies accordingly from 120 to lessthan 12.5 mm.

Drainage through virtually the entire area(Fig. 3) is to the southwest, joining the Dar­ling system, which debouches eventually intothe Southern Ocean. Gradients are initiallyhigh, but diminish rapidly to the southwest,

I

J

5

50 100 km! I

•o

Towns and townships withscheduled air services

Other towns and townships

Main access roads

Fig. 2. Towns and access.

Railway

Railway and main road

Edge of Surat Basin

5

50 100 km! I

•o

Towns and townships withscheduled air services

Other towns and townships

Main access roads

Fig. 2. Towns and access.

Railway

Railway and main road

Edge of Surat Basin

6

and are minimal on the alluvial tracts thatmake up one-third of the area (Fig. 4).There are no perennial streams in this areaof little runoff and high summer tempera­tures.

The area is almost entirely devoted toagriculture, particularly on the good soils inthe east, and the pastoral industry. The maincentres of population are concentrated on thegood clayey soils of the Injune Creek andRolling Downs Groups and on Cainozoicalluvium (see Fig. 4); they include Dalby(pop. 9000), Roma (6000), Goondiwindi(3500), Chinchilla (3300), St George(2250), and Miles (l500). The total popu­lation of the area is about 50 000.

Cash crops such as wheat, oats and sorg­hum are concentrated east of Meandarra,particularly on the alluvial plains of theCondamine River, although cotton is grownon a large irrigated area near St George.Beef cattle are concentrated in the rougheror drier country in the north, centre, andeast, and sheep are raised for wool in thesouthwest. Forestry is important on thesandy country north of Chinchilla, west ofCecil Plains and Millmerran, and aroundInglewood.

Scheduled air services call at many of thelarger centres (Fig. 2), and east-west raillinks connect Brisbane with Charleville(west of Morven), Glenmorgan, and Dirran­bandi. A well developed network of roadslinks all the major population centres andimportant farming areas. Sealed roads ex­tend for some distance north and south ofthe Warrego Highway, which connects Bris­bane and Charleville, but elsewhere arecommon only in the more densely popu­lated eastern third of the area. Unsealedroads are generally passable in sandy coun­try, but are impassable in clayey countryafter rain.

PhysiographyCainozoic stream systems have cut back

into the sediments of the Bowen and SuratBasins from the north and the southwest,leaving the Great Dividing Range as a majorerosional remnant (Fig. 3). The northerly­flowing streams have cut large drainagebasins and it is estimated that the Comet

River system, for example, has removed athickness of about 1000 m of Mesozoic sedi­mentary rocks and Tertiary basalt, assumingthat the early Cainozoic surface was rela­tively even.

In the Surat Basin proper, where the rain­fall is smaller and where gradients of thestreams are lower, the southwesterly-flowingstreams have been less effective erosiveagents than the northerly-flowing streams inthe Bowen Basin. Regarding the Tertiary(Oligocene or older) land surface as adatum (Fig. 4), it is apparent that thesoutherly-flowing streams have seldom cutdown more than 200 m. In wide areas, theold valleys have been filled with 100 m andmore (cross-section of Fig. 4; Fig. 48) ofCainozoic sediments, and the present allu­vial surface is only just below, or in placesactually above, the remnants of the Tertiarysurface. Much of the Cainozoic fill may beless than 15 000 years old and was depo­sited when run-off diminished after the lastglacial epoch.

The physiographic units are shown inFigure 4.

The basalt-capped mesas, which range inelevation from 450 to 1200 m, are the rem­nants of formerly widespread flows that filleddepressions in mid-Tertiary time. Their pres­ence shows that the topography has beencompletely inverted in the last 25 millionyears in many areas.

The dissected sandstone country withcuestas and mesas has formed where resist­ant sandstone and less resistant interbedscrop out, and have been incised by activestreams with considerable gradients. Theunit is confined to the Lower Jurassic andthe Upper Jurassic to Lower Cretaceoussandy sequences. In most of the basin, dipsrange from -! 0 to 2 0 and southerly-dippingcuestas have been formed, but in the eastdips are even lower and mesas have beenformed.

The dissected tablelands, representing theEarly Tertiary land surface, are confined tothe lower areas within the basin. The ferru­ginized and silicified land surface was moreresistant to erosion than the unalteredMesozoic rocks and is still being dissected.

J

6

and are minimal on the alluvial tracts thatmake up one-third of the area (Fig. 4).There are no perennial streams in this areaof little runoff and high summer tempera­tures.

The area is almost entirely devoted toagriculture, particularly on the good soils inthe east, and the pastoral industry. The maincentres of population are concentrated on thegood clayey soils of the Injune Creek andRolling Downs Groups and on Cainozoicalluvium (see Fig. 4); they include Dalby(pop. 9000), Roma (6000), Goondiwindi(3500), Chinchilla (3300), St George(2250), and Miles (l500). The total popu­lation of the area is about 50 000.

Cash crops such as wheat, oats and sorg­hum are concentrated east of Meandarra,particularly on the alluvial plains of theCondamine River, although cotton is grownon a large irrigated area near St George.Beef cattle are concentrated in the rougheror drier country in the north, centre, andeast, and sheep are raised for wool in thesouthwest. Forestry is important on thesandy country north of Chinchilla, west ofCecil Plains and Millmerran, and aroundInglewood.

Scheduled air services call at many of thelarger centres (Fig. 2), and east-west raillinks connect Brisbane with Charleville(west of Morven), Glenmorgan, and Dirran­bandi. A well developed network of roadslinks all the major population centres andimportant farming areas. Sealed roads ex­tend for some distance north and south ofthe Warrego Highway, which connects Bris­bane and Charleville, but elsewhere arecommon only in the more densely popu­lated eastern third of the area. Unsealedroads are generally passable in sandy coun­try, but are impassable in clayey countryafter rain.

PhysiographyCainozoic stream systems have cut back

into the sediments of the Bowen and SuratBasins from the north and the southwest,leaving the Great Dividing Range as a majorerosional remnant (Fig. 3). The northerly­flowing streams have cut large drainagebasins and it is estimated that the Comet

River system, for example, has removed athickness of about 1000 m of Mesozoic sedi­mentary rocks and Tertiary basalt, assumingthat the early Cainozoic surface was rela­tively even.

In the Surat Basin proper, where the rain­fall is smaller and where gradients of thestreams are lower, the southwesterly-flowingstreams have been less effective erosiveagents than the northerly-flowing streams inthe Bowen Basin. Regarding the Tertiary(Oligocene or older) land surface as adatum (Fig. 4), it is apparent that thesoutherly-flowing streams have seldom cutdown more than 200 m. In wide areas, theold valleys have been filled with 100 m andmore (cross-section of Fig. 4; Fig. 48) ofCainozoic sediments, and the present allu­vial surface is only just below, or in placesactually above, the remnants of the Tertiarysurface. Much of the Cainozoic fill may beless than 15 000 years old and was depo­sited when run-off diminished after the lastglacial epoch.

The physiographic units are shown inFigure 4.

The basalt-capped mesas, which range inelevation from 450 to 1200 m, are the rem­nants of formerly widespread flows that filleddepressions in mid-Tertiary time. Their pres­ence shows that the topography has beencompletely inverted in the last 25 millionyears in many areas.

The dissected sandstone country withcuestas and mesas has formed where resist­ant sandstone and less resistant interbedscrop out, and have been incised by activestreams with considerable gradients. Theunit is confined to the Lower Jurassic andthe Upper Jurassic to Lower Cretaceoussandy sequences. In most of the basin, dipsrange from -! 0 to 2 0 and southerly-dippingcuestas have been formed, but in the eastdips are even lower and mesas have beenformed.

The dissected tablelands, representing theEarly Tertiary land surface, are confined tothe lower areas within the basin. The ferru­ginized and silicified land surface was moreresistant to erosion than the unalteredMesozoic rocks and is still being dissected.

J

'Bollon.

~~'f(~! > 900 m

::";:.:.;':' 600-900 m... 300-600 m

<: 300m

km

Divide

900 '11 contour

600 m contour

300 m contour

Q/A /567

7

Fig. 3. Topography and drainage.

'Bollon.

~~'f(~! > 900 m

::";:.:.;':' 600-900 m... 300-600 m

<: 300m

km

Divide

900 '11 contour

600 m contour

300 m contour

Q/A /567

7

Fig. 3. Topography and drainage.

8

8LZJ~F3~

Alluvium

U"dulating clayey countrywith some outcrop

Undulating sandy countrywith some outcrop (UC)

Dissected tablelands representingTertiary land surface

Dissected sandstone countrywith cuestas and mesas (S)

.. Basalt capped mesas (B)

Bowen Basin and basement

Edge of Surat Basin

.u...w.... Escarpment forming edgeof Surat Basin

Major stream

(rn)600

Fig. 4. Physiographic units. B

B (rn)

'" 600UC

C:J

S C-

300

C

J

8

8LZJ~F3~

Alluvium

U"dulating clayey countrywith some outcrop

Undulating sandy countrywith some outcrop (UC)

Dissected tablelands representingTertiary land surface

Dissected sandstone countrywith cuestas and mesas (S)

.. Basalt capped mesas (B)

Bowen Basin and basement

Edge of Surat Basin

.u...w.... Escarpment forming edgeof Surat Basin

Major stream

(rn)600

Fig. 4. Physiographic units. B

B (rn)

'" 600UC

C:J

S C-

300

C

J

Much of thc basin was probably oncecapped by this surface, but it has beenalmost completely eroded in the higherareas. In places the surface is buried underCainozoic alluvium.

Undulating sandy country, with some out­crop, has formed on the upper part of theHutton Sandstone and on the sandstonesflanking the Texas High in the northern partof the New England Fold Belt. Stream gra­dients are low and incision slight, and cues­tas or mesas are only poorly developed.

Undulating clayey country, with someoutcrop, has been developed on the unresist­ant mudstones, siltstones, and labile sand­stones of the Injune Creek and RollingDowns Groups, where the Tertiary surfacehas been stripped. Stream gradients are gen­erally fairly low in these belts.

A lluvium, deposited by the major streamsystems, has reduced the pre-existing reliefin much of the basin. The history of thisalluvium, which forms broad clayey plainswhose gradient fits the streams, is complexand largely unknown.

Geological investigationsGeologists have worked in the Surat Basin

for more than a century. The general geologyis reviewed in the Explanatory Notes on thevarious 1:250 000 Sheet areas and in Day( 1964); Day (1969) has summarized thehistory of palaeontological research; and thehistory of the search for petroleum is re­viewed in Raggatt (1968). Since the early1960s, intensive mapping programs by theBureau of Mineral Resources (BMR) andGeological Survey of Queensland, and petro­leum search activities by company geolo­gists have completely revised our knowledgeof the basin. Geologists who contributedsubstantially to the mapping programs in­cluded N. F. Exon, E. N. MiUigan, B. R.Senior, B. M. Thomas, A. Mond, D. Burger,Danielle Senior, and Barbara Graham fromBMR, and D. J. Casey and R. F. Reiserfrom the Geological Survey of Queensland.Surface geology

Jack & Maitland (1895) mapped the in­take areas of the Great Artesian Basin andfrom this work the 'Blythesdale Braystone'was recognized (Jack, 1895a, b). Reeves

9

( 1947) discussed the petroleum potential ofthe Roma area and produced the firstdetailed geological map; much of his nomen­clature is still in use. Whitehouse (1954)made the first regional survey of the GreatArtesian Basin and produced a map at ascale of 40 miles to an inch of the Mesozoicand Cainozoic rocks of Queensland, whichwas incorporated in the geological map ofQueensland (Hill, 1953). Mack (1963) re­viewed the surface and subsurface geologyof the southern part of the Surat Basin, andpresented a regional map of the area. Day(1964) mapped the Roma-Wallumbilla areain detail, and attempted to resolve the con­fused stratigraphic nomenclature current atthat time.

The outcrop geology of the Surat Basinis now much better known because of thejoint regional mapping program of BMRand the Geological Survey of Queensland(1965 to 1969; see map). This has beenreported in detail in unpublished Records byExon, Milligan, Casey, & Galloway (1967),Exon, Reiser, Jensen, Burger, & Thomas( 1968), Thomas & Reiser (1968), andExon, Mond, Reiser, & Burger (1972). Allthe 1:250 000 maps and Explanatory Notescovering the area have been published.

Senior (1971) has discussed the historyof the Nebine Ridge, which bounds theSurat Basin to the west, and Exon, Lang­ford-Smith, & McDougall (1970) have dis­cussed the Early Tertiary period of deepweathering.

New nomenclature for the Jurassic InjuneCreek Group was proposed by Exon (1966)and the Springbok Sandstone Lens withinthe group was elevated to formation statusby Power & Devine (1968). New nomen­clature for the marine Cretaceous was estab­lished by Vine, Day, Milligan, Casey, Gallo­way, & Exon (1967), who restricted White­house's (1954) terms 'Roma' and 'Tambo'to the faunas alone. The Blythesdale Forma­tion of Day (1964) has been replaced by theMooga Sandstone and Bungil Formation ofExon & Vine (1970). Reiser (1970) pro­posed new nomenclature for the upper partof the Rolling Downs Group (marinc Cre­taceous) in the Surat area. Further subdivi-

Much of thc basin was probably oncecapped by this surface, but it has beenalmost completely eroded in the higherareas. In places the surface is buried underCainozoic alluvium.

Undulating sandy country, with some out­crop, has formed on the upper part of theHutton Sandstone and on the sandstonesflanking the Texas High in the northern partof the New England Fold Belt. Stream gra­dients are low and incision slight, and cues­tas or mesas are only poorly developed.

Undulating clayey country, with someoutcrop, has been developed on the unresist­ant mudstones, siltstones, and labile sand­stones of the Injune Creek and RollingDowns Groups, where the Tertiary surfacehas been stripped. Stream gradients are gen­erally fairly low in these belts.

A lluvium, deposited by the major streamsystems, has reduced the pre-existing reliefin much of the basin. The history of thisalluvium, which forms broad clayey plainswhose gradient fits the streams, is complexand largely unknown.

Geological investigationsGeologists have worked in the Surat Basin

for more than a century. The general geologyis reviewed in the Explanatory Notes on thevarious 1:250 000 Sheet areas and in Day( 1964); Day (1969) has summarized thehistory of palaeontological research; and thehistory of the search for petroleum is re­viewed in Raggatt (1968). Since the early1960s, intensive mapping programs by theBureau of Mineral Resources (BMR) andGeological Survey of Queensland, and petro­leum search activities by company geolo­gists have completely revised our knowledgeof the basin. Geologists who contributedsubstantially to the mapping programs in­cluded N. F. Exon, E. N. MiUigan, B. R.Senior, B. M. Thomas, A. Mond, D. Burger,Danielle Senior, and Barbara Graham fromBMR, and D. J. Casey and R. F. Reiserfrom the Geological Survey of Queensland.Surface geology

Jack & Maitland (1895) mapped the in­take areas of the Great Artesian Basin andfrom this work the 'Blythesdale Braystone'was recognized (Jack, 1895a, b). Reeves

9

( 1947) discussed the petroleum potential ofthe Roma area and produced the firstdetailed geological map; much of his nomen­clature is still in use. Whitehouse (1954)made the first regional survey of the GreatArtesian Basin and produced a map at ascale of 40 miles to an inch of the Mesozoicand Cainozoic rocks of Queensland, whichwas incorporated in the geological map ofQueensland (Hill, 1953). Mack (1963) re­viewed the surface and subsurface geologyof the southern part of the Surat Basin, andpresented a regional map of the area. Day(1964) mapped the Roma-Wallumbilla areain detail, and attempted to resolve the con­fused stratigraphic nomenclature current atthat time.

The outcrop geology of the Surat Basinis now much better known because of thejoint regional mapping program of BMRand the Geological Survey of Queensland(1965 to 1969; see map). This has beenreported in detail in unpublished Records byExon, Milligan, Casey, & Galloway (1967),Exon, Reiser, Jensen, Burger, & Thomas( 1968), Thomas & Reiser (1968), andExon, Mond, Reiser, & Burger (1972). Allthe 1:250 000 maps and Explanatory Notescovering the area have been published.

Senior (1971) has discussed the historyof the Nebine Ridge, which bounds theSurat Basin to the west, and Exon, Lang­ford-Smith, & McDougall (1970) have dis­cussed the Early Tertiary period of deepweathering.

New nomenclature for the Jurassic InjuneCreek Group was proposed by Exon (1966)and the Springbok Sandstone Lens withinthe group was elevated to formation statusby Power & Devine (1968). New nomen­clature for the marine Cretaceous was estab­lished by Vine, Day, Milligan, Casey, Gallo­way, & Exon (1967), who restricted White­house's (1954) terms 'Roma' and 'Tambo'to the faunas alone. The Blythesdale Forma­tion of Day (1964) has been replaced by theMooga Sandstone and Bungil Formation ofExon & Vine (1970). Reiser (1970) pro­posed new nomenclature for the upper partof the Rolling Downs Group (marinc Cre­taceous) in the Surat area. Further subdivi-

10

sions of the Injune Creek Group were madeby Swarbrick, Gray, & Exon (1973). Theoutcrop nomenclature now in use, and itsrelation to older schemes are shown inTable 18.

A general review of the macrofauna andpalaeogeography of the marine Cretaceoussequence in the Surat Basin is included inDay (1969).

Largely as a result of the surface map­ping and because of the need to relate it tothe subsurface geology, both BMR and theGeological Survey of Queensland carried outprograms of stratigraphic drilling in the area.

The BMR drilling was carried out in con­junction with the mapping; the holes wereup to 200 m deep, and cores were taken atselected intervals. The results have beenreported in various BMR Records and alsoby Mond & Senior (1970) for the south­western part of the basin and by Exon(1972a) for the northern and eastern partsof the basin.

The stratigraphic holes drilled by the Geo­logical Survey of Queensland were up to450 m deep, with a high proportion of cor­ing. One project (see also AlIen, 1971) wasto provide representative material for theentire Surat Basin sequence; the results havebeen recorded by Gray (1968, 1972).Another project (Swarbrick, 1973) was toinvestigate the stratigraphy and economicpotential of the Injune Creek Group.

PalaeontologyPalynology has proved to be the most

useful stratigraphic tool for the basin as awhole. The Jurassic sequence was studied byde Jersey & Paten (1964), Paten (1967),and Reiser & Williams (1969). The LowerCretaceous sequence has been intensivelystudied by Burger (1972, 1973, 1974, inprep.). Evans (1966) published a generalreview of Australian Mesozoic microfloras,including those from the Surat Basin.Lonergan ( 1973) reviewed the Triassic­Jurassic boundary in petroleum explorationwells in the southern part of the basin.Gould ( 1973) described fossil wood(Osmundacaulis hoskingii) from the upperpart of the Injune Creek Group, and he also

(Gould, 1974a) reviewed the entire fossilflora of the Walloon Coal Measures.

The study of marine Cretaceous shellymacrofossils has been outlined by Day (1964,1969). Whitehouse (e.g. 1954) collectedfrom the Roma area and established theexistence of the characteristic Roma fauna.Day (1964) collected extensively from theMinmi Member of his 'Blythesdale Forma­tion' and from the overlying Doncaster Mem­ber (his 'Roma Formation') and recognizedsimilarities and differences between the twoAptian faunas. Day (1968) has describedthe Minmi fauna in considerable detail. Day( 1969) presented faunal lists for four majorfaunas in the Surat Basin: the Nullawurtfauna of probable Neocomian age, the earlyAptian Minmi fauna, the late Aptian Don­caster (=Roma) fauna, and the earlyAlbian Coreena (=early Tambo) fauna.Day (1974) described most of the sparseAptian ammonite fauna found in the Don­caster Member in the Surat Basin.

Haig (1973) produced the first broadlybased study of the Early Cretaceous fora­minifera of the Surat Basin.

Petroleum searchThe search for petroleum is here divided

into geophysical surveys, which were usedto define most of the targets, and the subse­quent drilling to assess the potential of thesetargets. Reports 011 selected geophysical sur­veys and petroleum exploration wells havebeen published (see Table 1).

BMR has carried out gravity surveys inthe area since 1947, and the gravity con­tours are overprinted on the 1: 1 000 000scale geological map. The gravity contoursare of considerable assistance in interpretingthe distribution of the basement rocks.

Following early work by BMR (Dooley,1950), which proved the value of themethod, Union Oil Development Corp.made aeromagnetic surveys in the easternpart of the basin. The results were reportedby Union & Adastra (1960), Kahanoff( 1962), and Aero Service Corporation( 1963). Our knowledge of the depth tobasement in the deeper parts of the BowenBasin depends entirely on these aeromag­netic data.

J

10

sions of the Injune Creek Group were madeby Swarbrick, Gray, & Exon (1973). Theoutcrop nomenclature now in use, and itsrelation to older schemes are shown inTable 18.

A general review of the macrofauna andpalaeogeography of the marine Cretaceoussequence in the Surat Basin is included inDay (1969).

Largely as a result of the surface map­ping and because of the need to relate it tothe subsurface geology, both BMR and theGeological Survey of Queensland carried outprograms of stratigraphic drilling in the area.

The BMR drilling was carried out in con­junction with the mapping; the holes wereup to 200 m deep, and cores were taken atselected intervals. The results have beenreported in various BMR Records and alsoby Mond & Senior (1970) for the south­western part of the basin and by Exon(1972a) for the northern and eastern partsof the basin.

The stratigraphic holes drilled by the Geo­logical Survey of Queensland were up to450 m deep, with a high proportion of cor­ing. One project (see also AlIen, 1971) wasto provide representative material for theentire Surat Basin sequence; the results havebeen recorded by Gray (1968, 1972).Another project (Swarbrick, 1973) was toinvestigate the stratigraphy and economicpotential of the Injune Creek Group.

PalaeontologyPalynology has proved to be the most

useful stratigraphic tool for the basin as awhole. The Jurassic sequence was studied byde Jersey & Paten (1964), Paten (1967),and Reiser & Williams (1969). The LowerCretaceous sequence has been intensivelystudied by Burger (1972, 1973, 1974, inprep.). Evans (1966) published a generalreview of Australian Mesozoic microfloras,including those from the Surat Basin.Lonergan ( 1973) reviewed the Triassic­Jurassic boundary in petroleum explorationwells in the southern part of the basin.Gould ( 1973) described fossil wood(Osmundacaulis hoskingii) from the upperpart of the Injune Creek Group, and he also

(Gould, 1974a) reviewed the entire fossilflora of the Walloon Coal Measures.

The study of marine Cretaceous shellymacrofossils has been outlined by Day (1964,1969). Whitehouse (e.g. 1954) collectedfrom the Roma area and established theexistence of the characteristic Roma fauna.Day (1964) collected extensively from theMinmi Member of his 'Blythesdale Forma­tion' and from the overlying Doncaster Mem­ber (his 'Roma Formation') and recognizedsimilarities and differences between the twoAptian faunas. Day (1968) has describedthe Minmi fauna in considerable detail. Day( 1969) presented faunal lists for four majorfaunas in the Surat Basin: the Nullawurtfauna of probable Neocomian age, the earlyAptian Minmi fauna, the late Aptian Don­caster (=Roma) fauna, and the earlyAlbian Coreena (=early Tambo) fauna.Day (1974) described most of the sparseAptian ammonite fauna found in the Don­caster Member in the Surat Basin.

Haig (1973) produced the first broadlybased study of the Early Cretaceous fora­minifera of the Surat Basin.

Petroleum searchThe search for petroleum is here divided

into geophysical surveys, which were usedto define most of the targets, and the subse­quent drilling to assess the potential of thesetargets. Reports 011 selected geophysical sur­veys and petroleum exploration wells havebeen published (see Table 1).

BMR has carried out gravity surveys inthe area since 1947, and the gravity con­tours are overprinted on the 1: 1 000 000scale geological map. The gravity contoursare of considerable assistance in interpretingthe distribution of the basement rocks.

Following early work by BMR (Dooley,1950), which proved the value of themethod, Union Oil Development Corp.made aeromagnetic surveys in the easternpart of the basin. The results were reportedby Union & Adastra (1960), Kahanoff( 1962), and Aero Service Corporation( 1963). Our knowledge of the depth tobasement in the deeper parts of the BowenBasin depends entirely on these aeromag­netic data.

J

11

TABLE 1. RELEVANT PETROLEUM SEARCH SUBSIDY ACTS PUBLICATIONS

No. 22. Associated Australian Oilfields N.L., 1964-AAO Pickanjinnie No. 1, Queensland, 36 pp.No. 27. Associated Australian Oilfields N.L., 1961-Eumamurrin (North Roma) seismic survey, 20 pp.No. 34. Associated Australian Oilfields N.L., 1962-South Roma seismic survey, Queensland, 1959,

12 pp.No. 35. Associated Australian Oilfields N.L., 1962-East Roma seismic survey, Queensland, 1959­

1960, 18 pp.No. 40. J. E. Mack, Jr, Union Oil Development Corporation 1963-Reconnaissance geology of the

Surat Basin, Queensland and New South Wales, 36 pp.No. 43. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, 1964-UKA Cabawin No. 1, Queensland, 178 pp.No.44 Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, 1964-UKA Cabwin East No. 1, Queensland, 56 pp.No. 45. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation, 1964-UKA Moonie No. 1, Queensland, 94 pp.No. 46. Associated Australian Oilfields N.L., 1966-Summary of data and results, Surat Basin,

Queensland: AAO Winnathoola No. I, AAO Kooringa No. 1, AAO Pleasant Hills No.I, 24 pp.

No.51. Associated Australian Oilfields N.L., 1964-AAO Combarngo No. I, Queensland, 50 pp.No. 53. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, I964-Summary of data and results: Surat Basin, Queensland:UKA Wandoan No. I, UKA Burunga No. 1, 20 pp.

No. 57. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, I965-Summary of data and results: Surat Basin, Queensland:UKA Middle Creek No. I, UKA Southwood No. I, 18 pp.

No. 58. Phillips Petroleum Company, Sunray DX Oil Company, and Queensland American Oil Com­pany, 1965-Summary of data and results: Surat Basin, Queensland: PSQA Durabilla No.I, PSQA Kogan No. I, PSQA Kogan South No. I, 30 pp.

No. 59. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, 1965-UKA Wandoan No. I, Queensland, 58 pp.

No.61. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, 1965-Summary of data and results: Surat Basin, Queensland:UKA Flinton No. I, UKA Coomrith No. 1, UKA Wunger No. 1, 26 pp.

The effectiveness of the seismic explora­tion method in this area was first shown byBMR surveys in the period of 1954 to 1960.Since then a great deal of reconnaissanceand detailed seismic work has been done forthe Associated Group in the Roma area, forPhillips Petroleum Co. in the Kogan-CecilPlains area, and for Union Oil DevelopmentCorp. elsewhere in the basin (see relevantExplanatory Notes). Seismic surveys arenow a normal prerequisite for all wildcatwells in the basin, and up to six persistentreflectors are present.

Successful exploration in the Surat Basinhas been virtually confined to the RomaShelf and to the Moonie and Alton areas. Ageneral review of the main reservoirs in theSurat Basin is given by Hogetoorn (1968).

Various papers dealing with the RomaShelf have been published by geologists ofMines Administration Pty Ltd; they include

a review of exploration methods by Swindon( 1965), a case history of fields and reser­voirs by Swindon (1968), and a discussionof stratigraphic traps by Traves (1971 ) .Sell, Brown, & Groves (1972) made a de­tailed study of hydrocarbon-producing LowerJurassic sandstones, including their strati­graphy, lithology, and depositional environ­ment. Detailed studies of selected gas fieldshave been carried out by Mines Administra­tion and the Geological Survey of Queens­land: the Bony Creek field by Power(1966), Pickanjinnie by Gray (1969), andPine Ridge and Raslie by Hogetoorn(1970).

Similar studies of the Moonie and Altonareas were made by geologists of Union OilDevelopment Corp.; they include earlyreports on the Moonie oil strike by Graves( 1963) and Moran & Gussow (1963), areport on the development of the field by

11

TABLE 1. RELEVANT PETROLEUM SEARCH SUBSIDY ACTS PUBLICATIONS

No. 22. Associated Australian Oilfields N.L., 1964-AAO Pickanjinnie No. 1, Queensland, 36 pp.No. 27. Associated Australian Oilfields N.L., 1961-Eumamurrin (North Roma) seismic survey, 20 pp.No. 34. Associated Australian Oilfields N.L., 1962-South Roma seismic survey, Queensland, 1959,

12 pp.No. 35. Associated Australian Oilfields N.L., 1962-East Roma seismic survey, Queensland, 1959­

1960, 18 pp.No. 40. J. E. Mack, Jr, Union Oil Development Corporation 1963-Reconnaissance geology of the

Surat Basin, Queensland and New South Wales, 36 pp.No. 43. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, 1964-UKA Cabawin No. 1, Queensland, 178 pp.No.44 Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, 1964-UKA Cabwin East No. 1, Queensland, 56 pp.No. 45. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation, 1964-UKA Moonie No. 1, Queensland, 94 pp.No. 46. Associated Australian Oilfields N.L., 1966-Summary of data and results, Surat Basin,

Queensland: AAO Winnathoola No. I, AAO Kooringa No. 1, AAO Pleasant Hills No.I, 24 pp.

No.51. Associated Australian Oilfields N.L., 1964-AAO Combarngo No. I, Queensland, 50 pp.No. 53. Union Oil Development Corporation, Kern County Land Company, and Australian Oil and

Gas Corporation Limited, I964-Summary of data and results: Surat Basin, Queensland:UKA Wandoan No. I, UKA Burunga No. 1, 20 pp.

No. 57. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, I965-Summary of data and results: Surat Basin, Queensland:UKA Middle Creek No. I, UKA Southwood No. I, 18 pp.

No. 58. Phillips Petroleum Company, Sunray DX Oil Company, and Queensland American Oil Com­pany, 1965-Summary of data and results: Surat Basin, Queensland: PSQA Durabilla No.I, PSQA Kogan No. I, PSQA Kogan South No. I, 30 pp.

No. 59. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, 1965-UKA Wandoan No. I, Queensland, 58 pp.

No.61. Union Oil Development Corporation, Kern County Land Company, and Australian Oil andGas Corporation Limited, 1965-Summary of data and results: Surat Basin, Queensland:UKA Flinton No. I, UKA Coomrith No. 1, UKA Wunger No. 1, 26 pp.

The effectiveness of the seismic explora­tion method in this area was first shown byBMR surveys in the period of 1954 to 1960.Since then a great deal of reconnaissanceand detailed seismic work has been done forthe Associated Group in the Roma area, forPhillips Petroleum Co. in the Kogan-CecilPlains area, and for Union Oil DevelopmentCorp. elsewhere in the basin (see relevantExplanatory Notes). Seismic surveys arenow a normal prerequisite for all wildcatwells in the basin, and up to six persistentreflectors are present.

Successful exploration in the Surat Basinhas been virtually confined to the RomaShelf and to the Moonie and Alton areas. Ageneral review of the main reservoirs in theSurat Basin is given by Hogetoorn (1968).

Various papers dealing with the RomaShelf have been published by geologists ofMines Administration Pty Ltd; they include

a review of exploration methods by Swindon( 1965), a case history of fields and reser­voirs by Swindon (1968), and a discussionof stratigraphic traps by Traves (1971 ) .Sell, Brown, & Groves (1972) made a de­tailed study of hydrocarbon-producing LowerJurassic sandstones, including their strati­graphy, lithology, and depositional environ­ment. Detailed studies of selected gas fieldshave been carried out by Mines Administra­tion and the Geological Survey of Queens­land: the Bony Creek field by Power(1966), Pickanjinnie by Gray (1969), andPine Ridge and Raslie by Hogetoorn(1970).

Similar studies of the Moonie and Altonareas were made by geologists of Union OilDevelopment Corp.; they include earlyreports on the Moonie oil strike by Graves( 1963) and Moran & Gussow (1963), areport on the development of the field by

12

TABLE 2. RELEVANT UNION OIL DEVELOPMENT CORPORATION UNPUBLISHEDGEOLOGICAL REPORTS

(Available in Geological Survey of Queensland library)

No. 2. KELLER, A. S., 1960-Geology of the Cabawin Trend, Queensland, Australia.No. 3. McGARRY, D. 1., 1960-Review of Mesozoic and Permian stratigraphy, related to the Bowen

and Artesian Basin.No. 5. MACK, J. E., 1961-The geology of the Bowen and Surat Basins, Queensland.No. 6. WORIES, H., 196I-Subsurface correlations in Springsure-Roma area, and Bowen Basin,

Queensland, Australia.No. 7. MACK, J. E., 1961-The geology of the southern part of the Surat Basin, Queensland and

New South Wales.No. 8. MACK, J. E., 1962-Reconnaissance geology of the Surat Basin, Queensland and New South

Wales, Australia.*No.9A. KELLER, A. S., and WORIES, H., 1963-Relinquishment of a portion of Authority to

Prospect 57P.No. I!. MACK, J. E., 1964-Subsurface geology of the Moonie Trend, ATP 57P, Queensland,

Australia.No. 13. MACK, J. E., 1964-Subsurface geology of the Crowder-Weir Trend, ATP 57P, Queensland.No. 16. MACK, J. E., 1964-Subsurface geology of the UnduIla Nose, ATP 57P, Queensland.No. 17. MACK,1. E., 1965-Geologic report on subsidised drilling operations: UKA Giligulgul No. I,

UKA Gurulmundi No. I, UKA Weringa No. 1, Miles-Wandoan district, Bowen-Surat Basin.No. 19. KELLER, A. S., and BURROUGH, H., 1965-ReIinquishment of a portion of Authority to

Prospect 57P, Queensland, Australia.No. 22. HERRMANN, F. A., and KELLER, A. S., 1966-Relinquishment of a portion of Authority

to Prospect 57P, Queensland, Australia.No. 25. CAREY, A. R, and KURASH, G. E., 1969-Relinquishment of a portion of Authority to

Prospect 145P, Queensland, Australia.

* Published as Petroleum Search Subsidy Acts (PSSA) volume No. 40.

Pyle & Buckley (1965), and a discussion ofreservoir conditions by Pyle (1967). Buck­ley, Bradley, & Zehnder (1969) have givencase histories of the Moonie and Alton OilFields. .Important unpublished geologicalreports by company geologists, which havebeen released, are listed in Table 2.

Possible oil migration paths in the SuratBasin have been discussed by Erickson(1965), Conybeare (1970), and Senior(1970. A study of correlations and litho­facies of the Jurassic sediments in the CecilPlains/Ipswich area was carried out byMeyers (1970). Power & Devine (1970)have published the results of an importantstudy of the subsurface stratigraphy, geo­logical history, and petroleum accumulationsin the Surat Basin, illustrated by a series ofisopach maps. Exon (1974) has done thesame for the Permo-Triassic sequence belowthe Surat Basin and the overlying LowerJurassic sequence.

The present studyThis study is an attempt to synthesize

knowledge gained over the years during thesurface mapping program with the greatamount of information available from com­pany geophysical and drilling activities.Several regional gravity and aeromagneticsurveys and scores of regional and detailedseismic surveys have been carried out, andalmost 500 wells have been drilled since thelate 1950s.

Many of these operations have been sub­sidized under the Commonwealth PetroleumSearch Subsidy Acts, and the results arepublic. Many more were carried out in areaswhich have since been relinquished, andfinal reports are now obtainable from theQueensland Department of Mines. Someexploration companies have generouslymade available unsubsidized and confiden­tial material for this study.

The petroleum exploration wells are con­centrated in areas where success has been

J

12

TABLE 2. RELEVANT UNION OIL DEVELOPMENT CORPORATION UNPUBLISHEDGEOLOGICAL REPORTS

(Available in Geological Survey of Queensland library)

No. 2. KELLER, A. S., 1960-Geology of the Cabawin Trend, Queensland, Australia.No. 3. McGARRY, D. 1., 1960-Review of Mesozoic and Permian stratigraphy, related to the Bowen

and Artesian Basin.No. 5. MACK, J. E., 1961-The geology of the Bowen and Surat Basins, Queensland.No. 6. WORIES, H., 196I-Subsurface correlations in Springsure-Roma area, and Bowen Basin,

Queensland, Australia.No. 7. MACK, J. E., 1961-The geology of the southern part of the Surat Basin, Queensland and

New South Wales.No. 8. MACK, J. E., 1962-Reconnaissance geology of the Surat Basin, Queensland and New South

Wales, Australia.*No.9A. KELLER, A. S., and WORIES, H., 1963-Relinquishment of a portion of Authority to

Prospect 57P.No. I!. MACK, J. E., 1964-Subsurface geology of the Moonie Trend, ATP 57P, Queensland,

Australia.No. 13. MACK, J. E., 1964-Subsurface geology of the Crowder-Weir Trend, ATP 57P, Queensland.No. 16. MACK, J. E., 1964-Subsurface geology of the UnduIla Nose, ATP 57P, Queensland.No. 17. MACK,1. E., 1965-Geologic report on subsidised drilling operations: UKA Giligulgul No. I,

UKA Gurulmundi No. I, UKA Weringa No. 1, Miles-Wandoan district, Bowen-Surat Basin.No. 19. KELLER, A. S., and BURROUGH, H., 1965-ReIinquishment of a portion of Authority to

Prospect 57P, Queensland, Australia.No. 22. HERRMANN, F. A., and KELLER, A. S., 1966-Relinquishment of a portion of Authority

to Prospect 57P, Queensland, Australia.No. 25. CAREY, A. R, and KURASH, G. E., 1969-Relinquishment of a portion of Authority to

Prospect 145P, Queensland, Australia.

* Published as Petroleum Search Subsidy Acts (PSSA) volume No. 40.

Pyle & Buckley (1965), and a discussion ofreservoir conditions by Pyle (1967). Buck­ley, Bradley, & Zehnder (1969) have givencase histories of the Moonie and Alton OilFields. .Important unpublished geologicalreports by company geologists, which havebeen released, are listed in Table 2.

Possible oil migration paths in the SuratBasin have been discussed by Erickson(1965), Conybeare (1970), and Senior(1970. A study of correlations and litho­facies of the Jurassic sediments in the CecilPlains/Ipswich area was carried out byMeyers (1970). Power & Devine (1970)have published the results of an importantstudy of the subsurface stratigraphy, geo­logical history, and petroleum accumulationsin the Surat Basin, illustrated by a series ofisopach maps. Exon (1974) has done thesame for the Permo-Triassic sequence belowthe Surat Basin and the overlying LowerJurassic sequence.

The present studyThis study is an attempt to synthesize

knowledge gained over the years during thesurface mapping program with the greatamount of information available from com­pany geophysical and drilling activities.Several regional gravity and aeromagneticsurveys and scores of regional and detailedseismic surveys have been carried out, andalmost 500 wells have been drilled since thelate 1950s.

Many of these operations have been sub­sidized under the Commonwealth PetroleumSearch Subsidy Acts, and the results arepublic. Many more were carried out in areaswhich have since been relinquished, andfinal reports are now obtainable from theQueensland Department of Mines. Someexploration companies have generouslymade available unsubsidized and confiden­tial material for this study.

The petroleum exploration wells are con­centrated in areas where success has been

J

13

TABLE 3. SOURCE OF GEOPHYSICAL DATA USED FOR STRUCTURE CONTOUR MAPS

Horizon

Basement

Permian 's'Permian'L'

Evergreen 'G' andrelated horizons

Walloon 'F'

Company Report Area

UKA Kahanoff* (1962) Mimosa SynclineUKA GR 19 SouthwestUKA GR 22 SouthwestUKA GR 25 Mimosa SynclineMinad Not released Roma ShelfUKA GR 25 Mimosa SynclineUKA GR 19 Northernmost part of

Mimosa SynclineUKA GR 22 Northern part of

Mimosa SynclineUKA GR 25 Mimosa SynclineMinad Not released North, including Mimosa

SynclineUKA GR 25 Mimosa Syncline and

southwestMinad Not released NorthPhillips Fjelstul & Beck East

(1963 )UKA United Geophysical Southwest

Corp. (1963)Minad Not releasad North

* This is an aeromagnetic survey, all others are seismic.Note: GR = Union Oil Company geological report. These are relinquishment reports listed in Table 2.

achieved, particularly on the Roma Shelfand along the eastern hinge-line, but thereare few wells in the middle of the MimosaSyncline and in the western part of thebasin. Fortunately, over 250 water boreshave been wireline-Iogged in recent years aspart of a continuing BMR program to pro­vide hydrological and stratigraphic data inthe Great Artesian Basin (see Appendix 5).These logs have been of great use, especiallyin areas where there are few petroleumexploration wells.

As a first step in this study, the best avail­able seismic data for various horizonsthroughout the basin (Table 3) were re­duced and generalized to provide structurecontour maps; the main horizons involvedwere basement, the top of the Permiansequence, the Evergreen Formation Resis­tivity Marker, and the top of the WalloonCoal Measures.

Then several well correlation diagrams(PIs 2-8) were drawn up for the Jurassic­Cretaceous sequence and correlations weregradually established and modified until acoherent picture was obtained. Basically thecorrelation was lithological, with littleemphasis on time-lines. Once these correla-

tion lines had been established, other wellswere correlated with those on the correlationlines, until some 260 wells had been cor­related, giving as dense a coverage as wasconsidered necessary. Then similar correla­tions were carried out using the wireline logs(gamma, neutron when available, and litho­logical) of 170 water-bores, and these weretied in with nearby petroleum explorationwells where possible.

This work has made use of additional(especially water-bore) data to that ofPower & Devine (1970) and the intervalsstudied and conclusions arrived at vary sig­nificantly for parts of the sequence. Fewerdata were available for the Permo-Triassicsequence and the correlations were mostlybased on the checking of company picks,making use of the petrographic work and thecorrelations of the Institute Fran~aise duPetrole (Tissot, 1963; Fehr, 1965) and ofBMR co-workers. Thus much less originalwork was involved than was the case withthe Jurassic-Cretaceous sequence. It is con­sidered that a full-scale study of the Permo­Triassic sequence would be very worthwhile.

Once well correlations and picks had beenfirmly established, seven structural maps at

13

TABLE 3. SOURCE OF GEOPHYSICAL DATA USED FOR STRUCTURE CONTOUR MAPS

Horizon

Basement

Permian 's'Permian'L'

Evergreen 'G' andrelated horizons

Walloon 'F'

Company Report Area

UKA Kahanoff* (1962) Mimosa SynclineUKA GR 19 SouthwestUKA GR 22 SouthwestUKA GR 25 Mimosa SynclineMinad Not released Roma ShelfUKA GR 25 Mimosa SynclineUKA GR 19 Northernmost part of

Mimosa SynclineUKA GR 22 Northern part of

Mimosa SynclineUKA GR 25 Mimosa SynclineMinad Not released North, including Mimosa

SynclineUKA GR 25 Mimosa Syncline and

southwestMinad Not released NorthPhillips Fjelstul & Beck East

(1963 )UKA United Geophysical Southwest

Corp. (1963)Minad Not releasad North

* This is an aeromagnetic survey, all others are seismic.Note: GR = Union Oil Company geological report. These are relinquishment reports listed in Table 2.

achieved, particularly on the Roma Shelfand along the eastern hinge-line, but thereare few wells in the middle of the MimosaSyncline and in the western part of thebasin. Fortunately, over 250 water boreshave been wireline-Iogged in recent years aspart of a continuing BMR program to pro­vide hydrological and stratigraphic data inthe Great Artesian Basin (see Appendix 5).These logs have been of great use, especiallyin areas where there are few petroleumexploration wells.

As a first step in this study, the best avail­able seismic data for various horizonsthroughout the basin (Table 3) were re­duced and generalized to provide structurecontour maps; the main horizons involvedwere basement, the top of the Permiansequence, the Evergreen Formation Resis­tivity Marker, and the top of the WalloonCoal Measures.

Then several well correlation diagrams(PIs 2-8) were drawn up for the Jurassic­Cretaceous sequence and correlations weregradually established and modified until acoherent picture was obtained. Basically thecorrelation was lithological, with littleemphasis on time-lines. Once these correla-

tion lines had been established, other wellswere correlated with those on the correlationlines, until some 260 wells had been cor­related, giving as dense a coverage as wasconsidered necessary. Then similar correla­tions were carried out using the wireline logs(gamma, neutron when available, and litho­logical) of 170 water-bores, and these weretied in with nearby petroleum explorationwells where possible.

This work has made use of additional(especially water-bore) data to that ofPower & Devine (1970) and the intervalsstudied and conclusions arrived at vary sig­nificantly for parts of the sequence. Fewerdata were available for the Permo-Triassicsequence and the correlations were mostlybased on the checking of company picks,making use of the petrographic work and thecorrelations of the Institute Fran~aise duPetrole (Tissot, 1963; Fehr, 1965) and ofBMR co-workers. Thus much less originalwork was involved than was the case withthe Jurassic-Cretaceous sequence. It is con­sidered that a full-scale study of the Permo­Triassic sequence would be very worthwhile.

Once well correlations and picks had beenfirmly established, seven structural maps at

14

a scale of 1: 1 000 000 were drawn (PIs9-15), making use of the seismic compila­tions and the well and water-bore data. Iso­pach maps (e.g. PIs 16-2 I) were then drawnfor selected intervals bounded by relativelydistinctive horizons which could be tracedbasinwide and which were believed to berelatively time-synchronous. Finally, twopalaeographic maps (Figs 17, 18) weredrawn to show the sequence immediatelyabove and below the pre-Jurassic uncon­formity, and the present structure of thatunconformity.

The various correlation diagrams andmaps form the basis for much of this Bul­letin. The maps are not claimed to be accur­ate in detail, but are believed to present acoherent regional picture which was notpreviously available.

Acknowledgments1 most gratefully acknowledge my debt to

the geologists of various companies for thegreat deal of help they have given me overthe years-especially those of Mines Ad­ministration Pty Ltd, Union Oil Develop­ment Corp., PhilIips Petroleum Co., andAmerican Overseas Petroleum Pty Ltd. Aclose working relationship with the geolo­gists of the Petroleum Section of the Geo­logical Survey of Queensland has been ofimmense benefit.

Lithological nomenclatureCrook's (1960) classification of arenites

is followed with slight modification. 'Arenite'is used as the generalized non-genetic termfor sand-size clastic material. The generallyaccepted arbitrary figure of 75 percentmatrix is taken as the division between are­nite and mudstone. All the arenites des­cribed fall into Crook's genetic subdivisionof 'sandstone'-traction current deposits.Sandstones in which quartz forms more than90 percent of the clasts are called'quartzose'; 75 to 90 percent, 'sublabile';less than 75 percent, 'labile'; and less than30 percent, 'very labile'. If the feldspar:lithic ratio is greater than 3: I, or less than1:3 respectively, the qualifying terms 'feld-

spathic' or 'lithic' can be used with 'sublabilesandstone'; 'labile sandstone' can be 'feld­spathic sandstone' or 'lithic sandstone'; andvery labile sandstone can be 'very feldspa­thic' or 'very lithic'.

'Siltstone' is used as a grainsize term(1/16-1/56 mm). 'Mudstone' is used as ageneral term for non-fissile sediments of thelutite class, and 'shale' is defined as a fissilemudstone. 'C1aystone' is used for sedimentconsisting dominantly of clay minerals.

The Wentworth Scale has been followedfor grainsize terminology (Pettijohn, 1957).

STRUCTUREThe relation of the Bowen and Surat

Basins to the surrounding structures isshown in Figure 1; the solid geology of thearea studied is outlined in Figure 5 and themain structural units in Figure 6.

The meridional Bowen Basin is boundedin the east by the line of thrust faults alongthe western edge of the South Coastal Struc­tural High (Auburn Arch) and the NewEngland Fold Belt, and in the southwest bythe St George/Bollon Slope. It intertongueswith the Galilee Basin across the NebineRidge and with the Gunnedah Basin acrossthe Narrabri Structural High.

The Surat Basin is bounded in the eastby the Auburn Arch and the New EnglandFold Belt; between these two basementblocks it intertongues with the MoretonBasin across the KumbarilIa Ridge. To thewest it intertongues with the EromangaBasin across the Nebine Ridge and its broadsoutherly extension, the Cunnamulla Shelf.In the south it is bounded by the CentralWest Folded Belt, and in the north it hasbeen eroded.

By comparing Figures 6 and 7, the basisof the subdivision into structural units withinthe Surat Basin becomes apparent. Thedominant feature of the structure contoursof the basement surface'" (Fig. 7) is themeridional Taroom Trough, bounded in theeast by the Burunga-Leichhardt Fault Zoneand the Goondiwindi-Moonie Fault Zone,both of which are thrusts, and in the west by

* 'Basement' is here regarded as the rocks which were present before Bowen Basin sedimentation began,together with Permo-Triassic batholiths.

14

a scale of 1: 1 000 000 were drawn (PIs9-15), making use of the seismic compila­tions and the well and water-bore data. Iso­pach maps (e.g. PIs 16-2 I) were then drawnfor selected intervals bounded by relativelydistinctive horizons which could be tracedbasinwide and which were believed to berelatively time-synchronous. Finally, twopalaeographic maps (Figs 17, 18) weredrawn to show the sequence immediatelyabove and below the pre-Jurassic uncon­formity, and the present structure of thatunconformity.

The various correlation diagrams andmaps form the basis for much of this Bul­letin. The maps are not claimed to be accur­ate in detail, but are believed to present acoherent regional picture which was notpreviously available.

Acknowledgments1 most gratefully acknowledge my debt to

the geologists of various companies for thegreat deal of help they have given me overthe years-especially those of Mines Ad­ministration Pty Ltd, Union Oil Develop­ment Corp., PhilIips Petroleum Co., andAmerican Overseas Petroleum Pty Ltd. Aclose working relationship with the geolo­gists of the Petroleum Section of the Geo­logical Survey of Queensland has been ofimmense benefit.

Lithological nomenclatureCrook's (1960) classification of arenites

is followed with slight modification. 'Arenite'is used as the generalized non-genetic termfor sand-size clastic material. The generallyaccepted arbitrary figure of 75 percentmatrix is taken as the division between are­nite and mudstone. All the arenites des­cribed fall into Crook's genetic subdivisionof 'sandstone'-traction current deposits.Sandstones in which quartz forms more than90 percent of the clasts are called'quartzose'; 75 to 90 percent, 'sublabile';less than 75 percent, 'labile'; and less than30 percent, 'very labile'. If the feldspar:lithic ratio is greater than 3: I, or less than1:3 respectively, the qualifying terms 'feld-

spathic' or 'lithic' can be used with 'sublabilesandstone'; 'labile sandstone' can be 'feld­spathic sandstone' or 'lithic sandstone'; andvery labile sandstone can be 'very feldspa­thic' or 'very lithic'.

'Siltstone' is used as a grainsize term(1/16-1/56 mm). 'Mudstone' is used as ageneral term for non-fissile sediments of thelutite class, and 'shale' is defined as a fissilemudstone. 'C1aystone' is used for sedimentconsisting dominantly of clay minerals.

The Wentworth Scale has been followedfor grainsize terminology (Pettijohn, 1957).

STRUCTUREThe relation of the Bowen and Surat

Basins to the surrounding structures isshown in Figure 1; the solid geology of thearea studied is outlined in Figure 5 and themain structural units in Figure 6.

The meridional Bowen Basin is boundedin the east by the line of thrust faults alongthe western edge of the South Coastal Struc­tural High (Auburn Arch) and the NewEngland Fold Belt, and in the southwest bythe St George/Bollon Slope. It intertongueswith the Galilee Basin across the NebineRidge and with the Gunnedah Basin acrossthe Narrabri Structural High.

The Surat Basin is bounded in the eastby the Auburn Arch and the New EnglandFold Belt; between these two basementblocks it intertongues with the MoretonBasin across the KumbarilIa Ridge. To thewest it intertongues with the EromangaBasin across the Nebine Ridge and its broadsoutherly extension, the Cunnamulla Shelf.In the south it is bounded by the CentralWest Folded Belt, and in the north it hasbeen eroded.

By comparing Figures 6 and 7, the basisof the subdivision into structural units withinthe Surat Basin becomes apparent. Thedominant feature of the structure contoursof the basement surface'" (Fig. 7) is themeridional Taroom Trough, bounded in theeast by the Burunga-Leichhardt Fault Zoneand the Goondiwindi-Moonie Fault Zone,both of which are thrusts, and in the west by

* 'Basement' is here regarded as the rocks which were present before Bowen Basin sedimentation began,together with Permo-Triassic batholiths.

St George

A1acintyre

15

p,

~~

~

"A 100 km1 !

Boundary of isop~ched intervals

Other geological houndaries

Cainozoic Alluvium

Rolling Downs Gp (younger than Kid)

Doncaster Mbr (Kid) and Bungil Fm (Kly)

Hooray Sst (J-Kh), Mooga Sst (Klm), Orallo Fm (Juo),Gubberamunda Sst (Jug)Westbourne Fm (Juw), Adori Sst (Ja), Springbok Sst (Js),Pilliga Sst (Jp)

Walloon Coal Meas (Jw), Hutton Sst (Jlh), upper Marburg Sst (Jlm l) c:!JEvergreen Fm (JleJ, Precipice Sst (Jlp), lower Marburg Sst (Jlm 2),Mulgildie sequence (Jm)

Fig. 5. Solid geology.

Base of Surat Basin

Fault

Moolayember Fm,Clematis Gp

Rewan Gp

Blackwater Gp

Back Creek Gp

Palaeozoic volcanicsand sediments

Granite

Schist and gneiss

St George

A1acintyre

15

p,

~~

~

"A 100 km1 !

Boundary of isop~ched intervals

Other geological houndaries

Cainozoic Alluvium

Rolling Downs Gp (younger than Kid)

Doncaster Mbr (Kid) and Bungil Fm (Kly)

Hooray Sst (J-Kh), Mooga Sst (Klm), Orallo Fm (Juo),Gubberamunda Sst (Jug)Westbourne Fm (Juw), Adori Sst (Ja), Springbok Sst (Js),Pilliga Sst (Jp)

Walloon Coal Meas (Jw), Hutton Sst (Jlh), upper Marburg Sst (Jlm l) c:!JEvergreen Fm (JleJ, Precipice Sst (Jlp), lower Marburg Sst (Jlm 2),Mulgildie sequence (Jm)

Fig. 5. Solid geology.

Base of Surat Basin

Fault

Moolayember Fm,Clematis Gp

Rewan Gp

Blackwater Gp

Back Creek Gp

Palaeozoic volcanicsand sediments

Granite

Schist and gneiss

16

.Morven

$~QP(

:: :;c:···f·' ....

..\.:. ...

. . .~ . . .

150°

HIGH

a/A/570

26°

28°

50 100 km'-----'------,

Regional dip of basement surface

Outcrop boundary of structural unit

Subsurface boundary of structural unit

~ Fault (teeth on downthrow side)

1 Merivale Fault zone

2 Abroath Fault zone

3 Hutton-Wallumbilla Fault zone

4 Burunga Fault zone

5 Leichhardt Fault

6 Undulla Fault

7 Moonie Fault

8 Goondiwindi Fault

9 Dirranbandi SynclineFig. 6. Structural elements.

J

16

.Morven

$~QP(

:: :;c:···f·' ....

..\.:. ...

. . .~ . . .

150°

HIGH

a/A/570

26°

28°

50 100 km'-----'------,

Regional dip of basement surface

Outcrop boundary of structural unit

Subsurface boundary of structural unit

~ Fault (teeth on downthrow side)

1 Merivale Fault zone

2 Abroath Fault zone

3 Hutton-Wallumbilla Fault zone

4 Burunga Fault zone

5 Leichhardt Fault

6 Undulla Fault

7 Moonie Fault

8 Goondiwindi Fault

9 Dirranbandi SynclineFig. 6. Structural elements.

J

the Nebine Ridge, the Roma Shelf, and theSt George/Bollon Slope. From a study ofseismic and gravity data and ERTS ima­gery, Bourke (I974b) has concluded thatthe Goondiwindi Fault in the Warialdaarea of northern New South Wales is defi­nitely a thrust and suggests that it may becontinuous with the Hunter-Mooki Thrustsystem to the south. Between the Moonieand Undulla Faults is a northeasterly trend­ing graben which may be an extension of theMulgildie Rift, as suggested by Power &Devine (1970). Few data exist on the inter­vening region, although the Target Stock­yard Creek No. 1 well has shown that therecannot be a large connecting graben. Be­tween the Undulla and Macintyre Faults isthe south-southwesterly-plunging UndullaNose.

The Taroom Trough is 10 000 m deep inthe north, shallowing to about 1600 m in thesouth. The thrust faults on the eastern mar­gin give the trough the general appearanceof a half-graben; the displacement on thefaults decreases from over 2000 m in thenorth to less than 1000 m south of Moonie.The regional basement slope into the troughis about 15 0 in the northeast, but in thenorthwest the slope is more gradual exceptin the deeper part of the basin. In the souththe regional slope is variable, but seldomexceeds 50 except near faults.

The St George/Bollon Slope and theChinchilla-Goondiwindi Slope fall towardthe Taroom Trough at less than 10. A note­worthy feature of the St George/BollonSlope is the northeasterly-falling depressionthat coincides in part with the DirranbandiSyncline and is extensively faulted (UnitedGeophysical Corp., 1963).

Two major fault systems are associatedwith the Roma Shelf. The Hutton-Wallum­billa Fault trends north-northwest and has awesterly downthrow of up to 800 m in thenorth. The Merivale and Arbroath Faults,which form the western limit of the RomaShelf, may be separate structures on thesame line of weakness. The maximumwesterly downthrow on the northerly-trend­ing Merivale Fault, which is probably athrust, exceeds 1000 m; on the northwest-

17

erly-trending Arbroath Fault it is about 1200m. Both faults are bounded in the west bynarrow half-grabens filled with pre-Jurassicsediments-the Merivale and ArbroathTroughs.

The structure contours on the top of thePermian coal measures (Fig. 8) are sub­dued reflections of contours on the basementmap, with dips generally only half as steep.They show that the Permian sequence islargely confined to the Taroom and DenisonTroughs, although it is also present on theRoma Shelf and the northern part of theNebine Ridge. The deepest area, some 6000m below sea level, is near Taroom.

The structure contours on the top of theEvergreen Formation (Fig. 9), constructedon a Lower Jurassic (early Surat Basin)horizon, still show the marked influence ofthe basement topography. The axis of theMimosa Syncline faithfully follows that ofthe Taroom Trough, but the basin is muchbroader and shallower than the trough. Thedeepest part of the basin has migrated to thesouth of Taroom, to near Meandarra, whereit is 1800 m below sea level. Displacementon the major faults seldom exceeds 200 m.

The structure contours on the top of theWalloon Coal Measures (Fig. 10) at aboutthe top of the Middle Jurassic show thedeclining influence of the Bowen Basin onthe Surat Basin. Superimposed on the meri­dional structure of the Mimosa Syncline is asouthwesterly-trending depression through StGeorge and Dirranbandi that correspondswith a depression in the basement (Fig. 7).The deepest parts of the basin lie along thisdepression, and range from 1300 m belowsea level near Meandarra to 1100 m nearDirranbandi. Dips are generally very gentle,and fault displacements are slight.

The structure contours on the top of theMooga and Hooray Sandstones (Fig. 11)and the contours on the top of the DoncasterMember (Fig. 12) are essentially similarand not very different from the structure ofthe top of the Walloon Coal Measures (Fig.10). Figure 11 shows that the deepest partof the basin, between Meandarra andTalwood, is 650 m below sea level. Thesouthwesterly-trending depression through

the Nebine Ridge, the Roma Shelf, and theSt George/Bollon Slope. From a study ofseismic and gravity data and ERTS ima­gery, Bourke (I974b) has concluded thatthe Goondiwindi Fault in the Warialdaarea of northern New South Wales is defi­nitely a thrust and suggests that it may becontinuous with the Hunter-Mooki Thrustsystem to the south. Between the Moonieand Undulla Faults is a northeasterly trend­ing graben which may be an extension of theMulgildie Rift, as suggested by Power &Devine (1970). Few data exist on the inter­vening region, although the Target Stock­yard Creek No. 1 well has shown that therecannot be a large connecting graben. Be­tween the Undulla and Macintyre Faults isthe south-southwesterly-plunging UndullaNose.

The Taroom Trough is 10 000 m deep inthe north, shallowing to about 1600 m in thesouth. The thrust faults on the eastern mar­gin give the trough the general appearanceof a half-graben; the displacement on thefaults decreases from over 2000 m in thenorth to less than 1000 m south of Moonie.The regional basement slope into the troughis about 15 0 in the northeast, but in thenorthwest the slope is more gradual exceptin the deeper part of the basin. In the souththe regional slope is variable, but seldomexceeds 50 except near faults.

The St George/Bollon Slope and theChinchilla-Goondiwindi Slope fall towardthe Taroom Trough at less than 10. A note­worthy feature of the St George/BollonSlope is the northeasterly-falling depressionthat coincides in part with the DirranbandiSyncline and is extensively faulted (UnitedGeophysical Corp., 1963).

Two major fault systems are associatedwith the Roma Shelf. The Hutton-Wallum­billa Fault trends north-northwest and has awesterly downthrow of up to 800 m in thenorth. The Merivale and Arbroath Faults,which form the western limit of the RomaShelf, may be separate structures on thesame line of weakness. The maximumwesterly downthrow on the northerly-trend­ing Merivale Fault, which is probably athrust, exceeds 1000 m; on the northwest-

17

erly-trending Arbroath Fault it is about 1200m. Both faults are bounded in the west bynarrow half-grabens filled with pre-Jurassicsediments-the Merivale and ArbroathTroughs.

The structure contours on the top of thePermian coal measures (Fig. 8) are sub­dued reflections of contours on the basementmap, with dips generally only half as steep.They show that the Permian sequence islargely confined to the Taroom and DenisonTroughs, although it is also present on theRoma Shelf and the northern part of theNebine Ridge. The deepest area, some 6000m below sea level, is near Taroom.

The structure contours on the top of theEvergreen Formation (Fig. 9), constructedon a Lower Jurassic (early Surat Basin)horizon, still show the marked influence ofthe basement topography. The axis of theMimosa Syncline faithfully follows that ofthe Taroom Trough, but the basin is muchbroader and shallower than the trough. Thedeepest part of the basin has migrated to thesouth of Taroom, to near Meandarra, whereit is 1800 m below sea level. Displacementon the major faults seldom exceeds 200 m.

The structure contours on the top of theWalloon Coal Measures (Fig. 10) at aboutthe top of the Middle Jurassic show thedeclining influence of the Bowen Basin onthe Surat Basin. Superimposed on the meri­dional structure of the Mimosa Syncline is asouthwesterly-trending depression through StGeorge and Dirranbandi that correspondswith a depression in the basement (Fig. 7).The deepest parts of the basin lie along thisdepression, and range from 1300 m belowsea level near Meandarra to 1100 m nearDirranbandi. Dips are generally very gentle,and fault displacements are slight.

The structure contours on the top of theMooga and Hooray Sandstones (Fig. 11)and the contours on the top of the DoncasterMember (Fig. 12) are essentially similarand not very different from the structure ofthe top of the Walloon Coal Measures (Fig.10). Figure 11 shows that the deepest partof the basin, between Meandarra andTalwood, is 650 m below sea level. Thesouthwesterly-trending depression through

18

••

-,-,- Edge of basin

Fault

50 100 kmL- ..l' ,

Contour; interval 200 m

Data point (Seismic andaeromagnetic data incorporated)

Contour; interval TOOO m

Fig. 7. Structure contours. top of basement, and basement rock types.

18

••

-,-,- Edge of basin

Fault

50 100 kmL- ..l' ,

Contour; interval 200 m

Data point (Seismic andaeromagnetic data incorporated)

Contour; interval TOOO m

Fig. 7. Structure contours. top of basement, and basement rock types.

• • .

~OMA.. . .." .. .

Lower Perm/an"" •only

•

_ Dirranbandi

•

..

km

-

•

Dalby _

..

•

-Q/A/572

19

26°

..,....,... Limit of Upper Permian sequence

Fault

Data point (Seismic data incorporated)

Contour; interval TOOO m

Contour; interval 500 m

Fig. 8. Stnlcture contours, top of Permian sequence.

• • .

~OMA.. . .." .. .

Lower Perm/an"" •only

•

_ Dirranbandi

•

..

km

-

•

Dalby _

..

•

-Q/A/572

19

26°

..,....,... Limit of Upper Permian sequence

Fault

Data point (Seismic data incorporated)

Contour; interval TOOO m

Contour; interval 500 m

Fig. 8. Stnlcture contours, top of Permian sequence.

20

• Moura

•

• Dirranbandi

50 100 km'--------'-,------',

•

•Q/A/573

~ Outcrop of Evergreen Fm

...,...,. Limit of Evergreen Fm

Outcrop top of Evergreen Fm

Fault

Contour; interval 200 m

--- Contour; interval 1000 m

Data point (Seismic data incorporated)

Fig. 9. Structure contours, top of Evergreen Fonnation.

20

• Moura

•

• Dirranbandi

50 100 km'--------'-,------',

•

•Q/A/573

~ Outcrop of Evergreen Fm

...,...,. Limit of Evergreen Fm

Outcrop top of Evergreen Fm

Fault

Contour; interval 200 m

--- Contour; interval 1000 m

Data point (Seismic data incorporated)

Fig. 9. Structure contours, top of Evergreen Fonnation.

148 0

50 100 km'-- .].1 -'1

150 0

•Moura

Theodore

•

Cracow•

Monto•

Mundubbera

•

Texas

•a/A/574

21

28 0

Outcrop of WalloonCoal Measures

..,.. Limit of Walloon Coal Measures

Outcrop top of WalloonCoal Measures

Fault

Contour; interval TOOO m

Contour; interval 200 m

Data point (Some seismic data incorporated)

Fig. 10. Structure contours, top of Walloon Coal Measures.

148 0

50 100 km'-- .].1 -'1

150 0

•Moura

Theodore

•

Cracow•

Monto•

Mundubbera

•

Texas

•a/A/574

21

28 0

Outcrop of WalloonCoal Measures

..,.. Limit of Walloon Coal Measures

Outcrop top of WalloonCoal Measures

Fault

Contour; interval TOOO m

Contour; interval 200 m

Data point (Some seismic data incorporated)

Fig. 10. Structure contours, top of Walloon Coal Measures.

22

Moura

• Theodore

Inglewood.

.Chinchilla

Injune.

.Cracow

• Taroom

.Wandoan

Mundubbera _

Dalby.

Cecil Plains•

Millmerran.

~exasQ/A/S75

50 100 km'-------'-,--------',

llijr==::===l~

Outcrop of Mooga andHooray Sandstones

Hooray Sandstone replacesGubberamunda-Mooga sequence

Limit of Mooga andHooray Sandstones

Outcrop top of Mooga andHooray Sandstones

Geological boundary

Fault

='1/= Structure contours

• Data point

Fig. 11. Strocture contours, top of Mooga and Hooray Sandstones.

22

Moura

• Theodore

Inglewood.

.Chinchilla

Injune.

.Cracow

• Taroom

.Wandoan

Mundubbera _

Dalby.

Cecil Plains•

Millmerran.

~exasQ/A/S75

50 100 km'-------'-,--------',

llijr==::===l~

Outcrop of Mooga andHooray Sandstones

Hooray Sandstone replacesGubberamunda-Mooga sequence

Limit of Mooga andHooray Sandstones

Outcrop top of Mooga andHooray Sandstones

Geological boundary

Fault

='1/= Structure contours

• Data point

Fig. 11. Strocture contours, top of Mooga and Hooray Sandstones.

Moura

• Theodore

.Cracow

23

•Injune•

• Taroom

.Wandoan

Mundubbera •

Dalby.

Cecil Plains•

Millmerran.

Inglewood•

•Texas

O/A/576

Limit of DoncasterMember

Outcrop top ofDoncaster Member

f777J Outcrop of Doncaster

lLZ::J Member

50I

100 kmI

- Fault

-0- Structure contours

Data point

Fig. 12. Strocture contours, top of Doncaster Member.

Moura

• Theodore

.Cracow

23

•Injune•

• Taroom

.Wandoan

Mundubbera •

Dalby.

Cecil Plains•

Millmerran.

Inglewood•

•Texas

O/A/576

Limit of DoncasterMember

Outcrop top ofDoncaster Member

f777J Outcrop of Doncaster

lLZ::J Member

50I

100 kmI

- Fault

-0- Structure contours

Data point

Fig. 12. Strocture contours, top of Doncaster Member.

24

TABLE 4. GENERAL STRATIGRAPHY

Albian

U. Aptian

Neocomian toL. Aptian

Neocomian

U. Jurassic

M.-U. Jurassic

M. Jurassic

L. Jurassic

Unconformity

Youngest L.Tria~sic

-M. Triassic

L. Triassic

U. Permian

L.-U. Permian

L. Permian

Unit

Griman Creek Formation

Surat SiltstoneCoreena Member(Wallumbilla Formation)

Doncaster Mudstone(Wallumbilla Formation)

Bungil Formation

Mooga Sandstone

Orallo Formation

Gubberamunda Sand­stoneWestbourne Formation

Springbok Sandstone

Walloon Coal Measures

Eurombah Formation

Hutton Sandstone

Evergreen Formation

Precipice Sandstone

Wandoan Formation(= Clematis Gp +Moolaycmber Fm)

Rewan Group(= Cabawin Fm)

Blackwater Group

Back Creek Group

Reids Dome Beds

MaximumThickness

(m)

480

150210

270

270

300

270

300

200

250

650

100

250

260

150

1800

3500

700

3000

2500

Environment of Deposition and Lithology

Paralic and freshwater: sandstone, siltstone,mudstoneMarine: siltstone, mudstone, sandstoneParalic and freshwater: siltstone, mudstone,sandstone

Marine: mudstone, some siltstone

Freshwater and paralic: mudstone, siltstone,sandstone

Freshwater: sandstone, some siltstone andmudstone

Freshwater: labile sandstone, siltstone, mud­stone, coalFreshwater: sandstone, some silstone andconglomerateFreshwater and possibly paralic: siltstone,mudstone, sandstone

Freshwater: labile sandstone, siltstone, mud­stone

Coal measures: labile sandstone, siltstone,mudstone, coalFreshwater sandstone, some conglomerate,siltstone and mudstone

Freshwater: sandstone, some siltstone andmudstoneFreshwater and paralic: siltstone, mudstone,sandstoneFreshwater: quartzose sandstone, some silt­stone and mudstone

Freshwater: sandstone, siltstone, shale, con­glomerate

Redbeds: mudstone, siltstone, multicolouredsandstone

Coal measures: shale, siltstone, sandstone,coal

Marine and paralic: shale, siltstone, sand­stone, conglomerate

Freshwater: conglomerate, sandstone, silt­stone, shale, coal

Dirranbandi is a prominent feature and ameridional rise between Talwood and Mun­gindi is a new feature.

Figure 12 still shows the reflection of theold trends but the results of the Late Juras­sic and Tertiary epeirogenic movements arepredominant. There is a general southerlytilt in much of the basin, and the deepestareas, 300 m below sea level, are aroundDirranbandi and in a small depression north

of Talwood. The meridional rise west of Tal­wood is almost joined to a rise extendingsouth of Surat, giving the basin a bilobateappearance. Displacement on the Goondi­windi-Moonie Fault and the various faultsaround Roma does not exceed 100 m.

In general, tectonic movement in the areatook the form of thrusting and asymmetricalfolding in the Late Permian and Triassic andof normal faulting and related folding there-

24

TABLE 4. GENERAL STRATIGRAPHY

Albian

U. Aptian

Neocomian toL. Aptian

Neocomian

U. Jurassic

M.-U. Jurassic

M. Jurassic

L. Jurassic

Unconformity

Youngest L.Tria~sic

-M. Triassic

L. Triassic

U. Permian

L.-U. Permian

L. Permian

Unit

Griman Creek Formation

Surat SiltstoneCoreena Member(Wallumbilla Formation)

Doncaster Mudstone(Wallumbilla Formation)

Bungil Formation

Mooga Sandstone

Orallo Formation

Gubberamunda Sand­stoneWestbourne Formation

Springbok Sandstone

Walloon Coal Measures

Eurombah Formation

Hutton Sandstone

Evergreen Formation

Precipice Sandstone

Wandoan Formation(= Clematis Gp +Moolaycmber Fm)

Rewan Group(= Cabawin Fm)

Blackwater Group

Back Creek Group

Reids Dome Beds

MaximumThickness

(m)

480

150210

270

270

300

270

300

200

250

650

100

250

260

150

1800

3500

700

3000

2500

Environment of Deposition and Lithology

Paralic and freshwater: sandstone, siltstone,mudstoneMarine: siltstone, mudstone, sandstoneParalic and freshwater: siltstone, mudstone,sandstone

Marine: mudstone, some siltstone

Freshwater and paralic: mudstone, siltstone,sandstone

Freshwater: sandstone, some siltstone andmudstone

Freshwater: labile sandstone, siltstone, mud­stone, coalFreshwater: sandstone, some silstone andconglomerateFreshwater and possibly paralic: siltstone,mudstone, sandstone

Freshwater: labile sandstone, siltstone, mud­stone

Coal measures: labile sandstone, siltstone,mudstone, coalFreshwater sandstone, some conglomerate,siltstone and mudstone

Freshwater: sandstone, some siltstone andmudstoneFreshwater and paralic: siltstone, mudstone,sandstoneFreshwater: quartzose sandstone, some silt­stone and mudstone

Freshwater: sandstone, siltstone, shale, con­glomerate

Redbeds: mudstone, siltstone, multicolouredsandstone

Coal measures: shale, siltstone, sandstone,coal

Marine and paralic: shale, siltstone, sand­stone, conglomerate

Freshwater: conglomerate, sandstone, silt­stone, shale, coal

Dirranbandi is a prominent feature and ameridional rise between Talwood and Mun­gindi is a new feature.

Figure 12 still shows the reflection of theold trends but the results of the Late Juras­sic and Tertiary epeirogenic movements arepredominant. There is a general southerlytilt in much of the basin, and the deepestareas, 300 m below sea level, are aroundDirranbandi and in a small depression north

of Talwood. The meridional rise west of Tal­wood is almost joined to a rise extendingsouth of Surat, giving the basin a bilobateappearance. Displacement on the Goondi­windi-Moonie Fault and the various faultsaround Roma does not exceed 100 m.

In general, tectonic movement in the areatook the form of thrusting and asymmetricalfolding in the Late Permian and Triassic andof normal faulting and related folding there-

after. In Permo-Triassic time uplift andintrusion in the east combined with east-westcompression gave rise to the eastern zone ofthrust faulting. The Merivale Fault is pro­bably a thrust which developed in responseto the east-west compressive stress but incontrast, the Arbroath Fault is an older(Early Permian) normal fault that deve­loped before compression. Post-Triassicmovements seem to have been related to iso­static readjustment, with limited movementson old fault lines, downwarping in areas ofsediment accumulation, and draping overbasement rises.

The epeirogenic movements of the LateJurassic and mid-Tertiary led to broad tiltingto the south and west, and slight movementson the old faults. The Tertiary epeirogenicmovements were associated with widespreadintrusion and extrusion of basic rocks.Together the two periods of epeirogenicmovement led to uplift of over 1000 m in thenorth and somewhat less in the east.

GEOLOGICAL EVOLUTIONThe general stratigraphy of the area is

summarized in Table 4 and more detailedstratigraphic information is provided onpages 66 et seq. An outline of the evolutionof the stratigraphic nomenclature for theBowen Basin is given in Table 13 and forthe Surat Basin in Table 18.

The rocks which existed in this areabefore sedimentation began in the BowenBasin in the Early Permian, as well as thePermo-Triassic batholiths, are regarded asbasement. Their distribution is shown inFigure 7. The Devonian Timbury Hills For­mation, which consists of indurated anddeformed sediments and metasediments,underlies most of the western half of thearea, and the Carboniferous to Permian sedi­mentary rocks and vo1canics of the 'KuttungFormation' occupy most of the eastern half.

The Timbury Hills Formation is com­posed mainly of terrestrial rocks that weredeformed during the Carboniferous Kanim­blan Orogeny, when the Roma granites (andpossibly the granites near Talwood andsouth of Mungallala) were intruded. The

25

large area of schist and gneiss south ofMorven, and the smaller area near StGeorge may be related to this period ofintrusion, or could be older.

The 'Kuttung Formation' is marine in partand was laid down in Late Carboniferousand Early Permian time. It was folded andintruded by the Auburn granite during thesame general time span, and was furtherdeformed and intruded by the granites ofthe Yarraman Complex during the Permo­Triassic Hunter-Bowen Orogeny.

Bowen BasinBy Early Permian time, the area described

comprised an exposed stable western blockcomposed of sediments and metasedimentsof the Timbury Hills Formation buttressedby bodies of schist, gneiss, and granite anda less stable eastern area consisting of Car­boniferous and Permian vo1canics and sedi­ments, which formed the floor of a shal10wsea. As a result of subsidence during thePermian, as much as 4000 m of sedimentaccumulated (Fig. 13).

While the Lower Permian CamboonAndesite and its equivalents were beingextruded, and some of the Auburn graniteswere being intruded, the thick coal measuresof the Reids Dome Beds were laid down inthe newly formed half-graben west of theArbroath Fault, and farther north in theDenison Trough.

In Early Permian (Artinskian) time, vol­canism declined and the predominantlymarine sediments of the Back Creek Groupwere laid down north and east of the emer­gent basement block. This steady thickeningto the northeast, from a veneer near Romato 3000 m north of Taroom, suggests thatsubsidence took place to the east of a hinge­line along the western side of the present­day Taroom Trough. Marine micro-organ­isms and terrestrial plant debris are abund­ant in the sediments, which accumulated ata rate probably as high as 15 cm per 1000years*. Transgressions and regressions tookplace in some areas.

The sea withdrew in the Late Permian andthe basin was filled with sediment, which

* All rates of subsidence refer to compacted sediment.

after. In Permo-Triassic time uplift andintrusion in the east combined with east-westcompression gave rise to the eastern zone ofthrust faulting. The Merivale Fault is pro­bably a thrust which developed in responseto the east-west compressive stress but incontrast, the Arbroath Fault is an older(Early Permian) normal fault that deve­loped before compression. Post-Triassicmovements seem to have been related to iso­static readjustment, with limited movementson old fault lines, downwarping in areas ofsediment accumulation, and draping overbasement rises.

The epeirogenic movements of the LateJurassic and mid-Tertiary led to broad tiltingto the south and west, and slight movementson the old faults. The Tertiary epeirogenicmovements were associated with widespreadintrusion and extrusion of basic rocks.Together the two periods of epeirogenicmovement led to uplift of over 1000 m in thenorth and somewhat less in the east.

GEOLOGICAL EVOLUTIONThe general stratigraphy of the area is

summarized in Table 4 and more detailedstratigraphic information is provided onpages 66 et seq. An outline of the evolutionof the stratigraphic nomenclature for theBowen Basin is given in Table 13 and forthe Surat Basin in Table 18.

The rocks which existed in this areabefore sedimentation began in the BowenBasin in the Early Permian, as well as thePermo-Triassic batholiths, are regarded asbasement. Their distribution is shown inFigure 7. The Devonian Timbury Hills For­mation, which consists of indurated anddeformed sediments and metasediments,underlies most of the western half of thearea, and the Carboniferous to Permian sedi­mentary rocks and vo1canics of the 'KuttungFormation' occupy most of the eastern half.

The Timbury Hills Formation is com­posed mainly of terrestrial rocks that weredeformed during the Carboniferous Kanim­blan Orogeny, when the Roma granites (andpossibly the granites near Talwood andsouth of Mungallala) were intruded. The

25

large area of schist and gneiss south ofMorven, and the smaller area near StGeorge may be related to this period ofintrusion, or could be older.

The 'Kuttung Formation' is marine in partand was laid down in Late Carboniferousand Early Permian time. It was folded andintruded by the Auburn granite during thesame general time span, and was furtherdeformed and intruded by the granites ofthe Yarraman Complex during the Permo­Triassic Hunter-Bowen Orogeny.

Bowen BasinBy Early Permian time, the area described

comprised an exposed stable western blockcomposed of sediments and metasedimentsof the Timbury Hills Formation buttressedby bodies of schist, gneiss, and granite anda less stable eastern area consisting of Car­boniferous and Permian vo1canics and sedi­ments, which formed the floor of a shal10wsea. As a result of subsidence during thePermian, as much as 4000 m of sedimentaccumulated (Fig. 13).

While the Lower Permian CamboonAndesite and its equivalents were beingextruded, and some of the Auburn graniteswere being intruded, the thick coal measuresof the Reids Dome Beds were laid down inthe newly formed half-graben west of theArbroath Fault, and farther north in theDenison Trough.

In Early Permian (Artinskian) time, vol­canism declined and the predominantlymarine sediments of the Back Creek Groupwere laid down north and east of the emer­gent basement block. This steady thickeningto the northeast, from a veneer near Romato 3000 m north of Taroom, suggests thatsubsidence took place to the east of a hinge­line along the western side of the present­day Taroom Trough. Marine micro-organ­isms and terrestrial plant debris are abund­ant in the sediments, which accumulated ata rate probably as high as 15 cm per 1000years*. Transgressions and regressions tookplace in some areas.

The sea withdrew in the Late Permian andthe basin was filled with sediment, which

* All rates of subsidence refer to compacted sediment.

26

•

Morver1'• •

Bollo~

Hebel

~

BD'"....

148 0

• St George

• Dirranbandi

~hallon

Upper Permian outcrop

Upper Permian CoalMeasures alone present

Lower Permian alone present

Erosional margin of isopachedsequence

50!

150 0

onto

Mundubbera.

% • '~~IoanoJ f·:.

i'.'I'lJI~ilesr-:f .ChinchillaI· •I"

" ndamine

Dalby.

Cecil Plains•

Millmerran.

Inglewood•

~asQ/A/577

100 kmI

Depositional margin of~opachedsequence

Geological boundary

Fault

-200- Isopachs-7000-

• Data pointFig. 13. Thickness of Permian sequence.

26

•

Morverf• •

Bollo~

Hebel

~

BD'"....

148 0

• St George

• Dirranbandi

~hallon

Upper Permian outcrop

Upper Permian CoalMeasures alone present

Lower Permian alone present

Erosional margin of isopachedsequence

50!

150 0

onto

Mundubbera.

% • '~~IoanoJ f·:.

i'.'I'lJI~ilesr-:f .ChinchillaI· •I"

" ndamine

Dalby.

Cecil Plains•

Millmerran.

Inglewood•

~asQ/A/577

100 kmI

Depositional margin of~opachedsequence

Geological boundary

Fault

-200- Isopachs-7000-

• Data pointFig. 13. Thickness of Permian sequence.

•

•

• Dirranbandi

50 100 kmL- LI --ll

•

..

•

•

•

•Dalby

..

•Q/A/578

27

26°

28°

Back Creek Group(L to U Permian) only

Blackwater Group(U Permian) outcrop

.,...,- Erosional margin

Data point

Depositional margin

Other geological boundary

Fault

Isopach; interval 100 m

Isopach; interval 50 m

Fig. 14. Thickness of Blackwater Group.

•

•

• Dirranbandi

50 100 kmL- LI --ll

•

..

•

•

•

•Dalby

..

•Q/A/578

27

26°

28°

Back Creek Group(L to U Permian) only

Blackwater Group(U Permian) outcrop

.,...,- Erosional margin

Data point

Depositional margin

Other geological boundary

Fault

Isopach; interval 100 m

Isopach; interval 50 m

Fig. 14. Thickness of Blackwater Group.

28

• •ROMA.

•

_ Dirranbandi

•\ 0 0

0'"\

o \

\0

Io Io ~

o \

\\. \ )

\", "'0

• Cracow

•

-

•

Dalby -

•

-Q/A/579

26°

28

50 100kmL- 1L- ...J1

~ Rewan Gp outcrop

ro-ol Cabawin Fm replaces~ RewanGp

Depositional margin

'T" ..,.. Erosional margin

Data point

~ Facies change

Other geological boundary

Fault

Isopach; interval TOOO m

Isopach; interval 200 m

Fig. 15. Thickness of Rewan Group and Cabawin Fonnation.

28

• •ROMA.

•

_ Dirranbandi

•\ 0 0

0'"\

o \

\0

Io Io ~

o \

\\. \ )

\", "'0

• Cracow

•

-

•

Dalby -

•

-Q/A/579

26°

28

50 100kmL- 1L- ...J1

~ Rewan Gp outcrop

ro-ol Cabawin Fm replaces~ RewanGp

Depositional margin

'T" ..,.. Erosional margin

Data point

~ Facies change

Other geological boundary

Fault

Isopach; interval TOOO m

Isopach; interval 200 m

Fig. 15. Thickness of Rewan Group and Cabawin Fonnation.

29

26°

28°

•

•

•Q/A/580

•

Dalby.

•

• Cracow

.Dirranbandi

••

,,1OU--...., ,./ \" - \ ../ ..... \ \

/ // \"/ \ \

/ \' \

\ \. \ \, \'\. ,./" .......... .. (') .

,',-ROMA~'. '." . .-1IIt. • .,. e. • I •-<;-7. ....,.

~• "! •• • I'!"-"" •\ .,~ .\. \...\ . \.I .,

I I\ ,..

• • • I) .. / ..

(( .

'"\ .1 ,.' '"1 (....-.:. ~J •• .,

• c../) • {'"

. " . ';'"' \,. \\ ,.\ /I .,

I'\ \\ \

50 100kmL- -.1' ---l'

L?:'! Lower Triassic (Rewan Gp.:::: ," and Cabawin Fm) only

P/'//'::I Clematis Gp-Moolayember~ Fm outcrop

'T""'" Erosional margin

--- Other geological boundary

Depositional margin - Fault

• Data point Isopach; interval 200 m

, Palaeocurrent direction Isopach; interval 100 m

Fig, 16. Thickness of Wandoan 'Formation.

29

26°

28°

•

•

•Q/A/580

•

Dalby.

•

• Cracow

.Dirranbandi

••

,,1OU--...., ,./ \" - \ ../ ..... \ \

/ // \"/ \ \

/ \' \

\ \. \ \, \'\. ,./" .......... .. (') .

,',-ROMA~'. '." . .-1IIt. • .,. e. • I •-<;-7. ....,.

~• "! •• • I'!"-"" •\ .,~ .\. \...\ . \.I .,

I I\ ,..

• • • I) .. / ..

(( .

'"\ .1 ,.' '"1 (....-.:. ~J •• .,

• c../) • {'"

. " . ';'"' \,. \\ ,.\ /I .,

I'\ \\ \

50 100kmL- -.1' ---l'

L?:'! Lower Triassic (Rewan Gp.:::: ," and Cabawin Fm) only

P/'//'::I Clematis Gp-Moolayember~ Fm outcrop

'T""'" Erosional margin

--- Other geological boundary

Depositional margin - Fault

• Data point Isopach; interval 200 m

, Palaeocurrent direction Isopach; interval 100 m

Fig, 16. Thickness of Wandoan 'Formation.

30

lapped onto the southwestern block. Coalaccumulated in swamps on an extensivecoastal plain, but the rate of sedimentationwas lower, at about 7 cm per 1000 years.Toward the end of the Late Permian, wide­spread granite emplacement took place inthe east, and uplift of the Texas High beganin the southeast. These movements wereassociated with compression and overthrust­ing from the east. The basinward thickeningevident in the south in the Late Permian(see Fig. 14) suggests that the TaroomTrough was beginning to form. In the north,however, where the sequence thickens to theeast, it appears that the eastern side of thetrough had not yet been developed, or thatits axis lay farther east.

In Early Triassic time, the coal swampsdried up and the fine-grained terrestrial red­beds (derived from red soils on nearby up­lands) of the Rewan Group were laid downin a more restricted area than the coal mea­sures (Fig. 15). South of Miles, Triassicsediments lapped against the coal measureswhich were being tilted and uplifted to formthe present structural basin. The Goondi­windi-Moonie and Leichhardt Faults wereformed during the emplacement of the Trias­sic granites in the southeast. Along the mar­gins of the faults massive conglomerates ofthe Cabawin Formation, derived from thePermo-Carboniferous terrain, were depo­sited South of Goondiwindi redbeds areabsent.

North of Roma the Triassic sequence isgenerally conformable with the coal mea­sures, except where movements on the Hut­ton-Wallumbilla and Merivale Faults led tothe stripping of any coal measures on up­thrown blocks. The thickening of thesequence to the northeast from Roma tobeyond Taroom (Fig. 15) shows that therethe eastern margin of the Taroom Troughhad still not been formed, and the RewanGroup was laid down conformably ·:)n thecoal measures. In the northeast, the rate ofdeposition of the Rewan Group may haveexceeded 30 cm per 1000 years.

From the late Early Triassic onwardsother terrestrial sediments gradually re­placed the redbeds, and the Wandoan For-

mation (mainly Middle Triassic) was laiddown (Fig. 16). It lapped much farther ontothe southwesterly basement block than anyof the earlier units. The Wandoan Forma­tion is generally conformable on the RewanGroup and Cabawin Formation but in thesouth and on parts of the Wandoan Axis(the anticline on which UKA Wandoan No.1 was drilled) it is unconformable on thePermian coal measures. Further movementson the Hutton-Wallumbilla and MerivaleFaults meant that upthrown blocks coveredwith Permian and Rewan Group sedimentswere exposed during the deposition of theWandoan Formation. The thinning of thesequence towards the fault zone to the eastof Taroom (see Fig. 16) indicates that thethrust-faults bounding the Taroom Troughto the northeast, including the BurungaFault, had begun to develop. The maximumrate of deposition of about 20 cm per 1000years occurs along the axis of the troughnorth of Taroom.

At the close of the Middle Triassic thesouthwest basement block was still exposed,but extensive plains underlain by sedimentsof the Wandoan Formation extended acrossthe Taroom Trough between the basementblock and the uplifted block to the east ofthe Burunga - Moonie - Goondiwindi FaultZone.

In the Late Triassic the compressionalforces declined, and movement on the thrustfaults bounding the Taroom Trough ended,deposition ceased, and widespread erosiontook place. The sediment liberated duringthis period of erosion may have been depo­sited in and beyond the Moreton Basin, andmost of the intrusions, which are nowexposed in the basement, were exhumed dur­ing this erosional period.

Thus deposition in the Bowen Basin wasfairly rapid, with sedimentation rates aver­aging 20 cm per 1000 years. The grosssequence of events was: marine deposition,followed by the deposition of coal measures,redbeds, and other terrestrial beds, andfinally, erosion. The thrust-faulting asso­ciated with the development of the TaroomTrough began in the Early Triassic in thesouth and ended in the Middle or Late

J

30

lapped onto the southwestern block. Coalaccumulated in swamps on an extensivecoastal plain, but the rate of sedimentationwas lower, at about 7 cm per 1000 years.Toward the end of the Late Permian, wide­spread granite emplacement took place inthe east, and uplift of the Texas High beganin the southeast. These movements wereassociated with compression and overthrust­ing from the east. The basinward thickeningevident in the south in the Late Permian(see Fig. 14) suggests that the TaroomTrough was beginning to form. In the north,however, where the sequence thickens to theeast, it appears that the eastern side of thetrough had not yet been developed, or thatits axis lay farther east.

In Early Triassic time, the coal swampsdried up and the fine-grained terrestrial red­beds (derived from red soils on nearby up­lands) of the Rewan Group were laid downin a more restricted area than the coal mea­sures (Fig. 15). South of Miles, Triassicsediments lapped against the coal measureswhich were being tilted and uplifted to formthe present structural basin. The Goondi­windi-Moonie and Leichhardt Faults wereformed during the emplacement of the Trias­sic granites in the southeast. Along the mar­gins of the faults massive conglomerates ofthe Cabawin Formation, derived from thePermo-Carboniferous terrain, were depo­sited South of Goondiwindi redbeds areabsent.

North of Roma the Triassic sequence isgenerally conformable with the coal mea­sures, except where movements on the Hut­ton-Wallumbilla and Merivale Faults led tothe stripping of any coal measures on up­thrown blocks. The thickening of thesequence to the northeast from Roma tobeyond Taroom (Fig. 15) shows that therethe eastern margin of the Taroom Troughhad still not been formed, and the RewanGroup was laid down conformably ·:)n thecoal measures. In the northeast, the rate ofdeposition of the Rewan Group may haveexceeded 30 cm per 1000 years.

From the late Early Triassic onwardsother terrestrial sediments gradually re­placed the redbeds, and the Wandoan For-

mation (mainly Middle Triassic) was laiddown (Fig. 16). It lapped much farther ontothe southwesterly basement block than anyof the earlier units. The Wandoan Forma­tion is generally conformable on the RewanGroup and Cabawin Formation but in thesouth and on parts of the Wandoan Axis(the anticline on which UKA Wandoan No.1 was drilled) it is unconformable on thePermian coal measures. Further movementson the Hutton-Wallumbilla and MerivaleFaults meant that upthrown blocks coveredwith Permian and Rewan Group sedimentswere exposed during the deposition of theWandoan Formation. The thinning of thesequence towards the fault zone to the eastof Taroom (see Fig. 16) indicates that thethrust-faults bounding the Taroom Troughto the northeast, including the BurungaFault, had begun to develop. The maximumrate of deposition of about 20 cm per 1000years occurs along the axis of the troughnorth of Taroom.

At the close of the Middle Triassic thesouthwest basement block was still exposed,but extensive plains underlain by sedimentsof the Wandoan Formation extended acrossthe Taroom Trough between the basementblock and the uplifted block to the east ofthe Burunga - Moonie - Goondiwindi FaultZone.

In the Late Triassic the compressionalforces declined, and movement on the thrustfaults bounding the Taroom Trough ended,deposition ceased, and widespread erosiontook place. The sediment liberated duringthis period of erosion may have been depo­sited in and beyond the Moreton Basin, andmost of the intrusions, which are nowexposed in the basement, were exhumed dur­ing this erosional period.

Thus deposition in the Bowen Basin wasfairly rapid, with sedimentation rates aver­aging 20 cm per 1000 years. The grosssequence of events was: marine deposition,followed by the deposition of coal measures,redbeds, and other terrestrial beds, andfinally, erosion. The thrust-faulting asso­ciated with the development of the TaroomTrough began in the Early Triassic in thesouth and ended in the Middle or Late

J

Mr,ura.

31

Schist and gneiss (Palaeozoic)Volcanics(M Triassic)

Wandoan Fm\M Triassic) *

•

Permeable in places

y7

•

•

•O/A/581

ZEO

~ Rewan Gp (L Triassic)

Blackwater Gp (U Permian)

* E;~;I Back Creek Gp (L Permian)

~ Kuttung Fm (Palaeozoic)

Timbury Hills Fm (Palaeozoic)

Granite (Palaeozoic- Triassi::)

Outcrop margin of Surat Basin

Other geological boundary

Fault

Contour on pre-Jurassicunconformity, interval 500 m

Data point

Fig. 17. Units immediately below the Surat Basin.

Mr,ura.

31

Schist and gneiss (Palaeozoic)Volcanics(M Triassic)

Wandoan Fm\M Triassic) *

•

Permeable in places

y7

•

•

•O/A/581

ZEO

~ Rewan Gp (L Triassic)

Blackwater Gp (U Permian)

* E;~;I Back Creek Gp (L Permian)

~ Kuttung Fm (Palaeozoic)

Timbury Hills Fm (Palaeozoic)

Granite (Palaeozoic- Triassi::)

Outcrop margin of Surat Basin

Other geological boundary

Fault

Contour on pre-Jurassicunconformity, interval 500 m

Data point

Fig. 17. Units immediately below the Surat Basin.

32

148 0 150 0

•Maura

Hooray Sst

Westbourne Fm

Adori Sst

Pilliga Sst

Walloon Coal Meas

Hutton Sst

* ~:~;I Evergreen Fm

50I

100 kmI

* l:::::J Precipice Sst

* Good aquifes are present

...... Outcrop margin of Surat Basin

--- Other geological boundary

_ Fault

Contour on unconformity;interval 500 m

Data point

Fig. 18. Units immediately above the pre-Jurassic uDConformity.

32

148 0 150 0

•Maura

Hooray Sst

Westbourne Fm

Adori Sst

Pilliga Sst

Walloon Coal Meas

Hutton Sst

* ~:~;I Evergreen Fm

50I

100 kmI

* l:::::J Precipice Sst

* Good aquifes are present

...... Outcrop margin of Surat Basin

--- Other geological boundary

_ Fault

Contour on unconformity;interval 500 m

Data point

Fig. 18. Units immediately above the pre-Jurassic unconformity.

o

•Dirranbandi

rloura

Theodore•

50 100 kmI I

Monto•

Mundubbera

•

.Texas

Q/A/583

33

~ Precipice Sst-Evergreen Fm

.,..,.. Erosional margin

Depositional margin

Fault

Other geological boundary

Isopach; interval 50 m

• Well data point ....... Palaeocurrent direction

... Measured section

Fig. 19. Thickness of Precipice Sandstone and Evergreen Formation.

o

•Dirranbandi

rloura

Theodore•

50 100 kmI I

Monto•

Mundubbera

•

.Texas

Q/A/583

33

~ Precipice Sst-Evergreen Fm

.,..,.. Erosional margin

Depositional margin

Fault

Other geological boundary

Isopach; interval 50 m

• Well data point ....... Palaeocurrent direction

... Measured section

Fig. 19. Thickness of Precipice Sandstone and Evergreen Formation.

34

076

-0

Bollo~

......... \67

Dirranbandi,

Hebel

50I

Moura,

100 kmI

• Theodore

o

.Monto

Mundubbera _

Inglewood_

•Texas

Q/A/584

Erosional margin of isopachedsequence

Depositional margin ofisopached sequence

Fault

-50- Isopachs

Well data point withvalue in metres

Measured section

_ Palaeocurrent direction

Fig. 20. Thickness of lower part of Precipice Sandstone.

34

076

-0

Bollo~

......... \67

Dirranbandi,

Hebel

50I

Moura,

100 kmI

• Theodore

o

.Monto

Mundubbera _

Inglewood_

•Texas

Q/A/584

Erosional margin of isopachedsequence

Depositional margin ofisopached sequence

Fault

-50- Isopachs

Well data point withvalue in metres

Measured section

_ Palaeocurrent direction

Fig. 20. Thickness of lower part of Precipice Sandstone.

---------- ..._------

35

148 0

•Moura

50

Theodore•

Cracow•

100 km

Monto•

Mundubbera•

Texas•Q/A/sas

28 0

~ Hutton Sst-WalloontL:LLL1 Coal Meas outcrop

TTT Erosional margin

- - Depositional margin

Data point

Fault

Other geological boundary

Isopach; interval 50 m

Fig. 21. Thickness of Button Sandstone and Walloon Coal Measures.

---------- ..._------

35

148 0

•Moura

50

Theodore•

Cracow•

100 km

Monto•

Mundubbera•

Texas•Q/A/sas

28 0

~ Hutton Sst-WalloontL:LLL1 Coal Meas outcrop

TTT Erosional margin

- - Depositional margin

Data point

Fault

Other geological boundary

Isopach; interval 50 m

Fig. 21. Thickness of Button Sandstone and Walloon Coal Measures.

36

148 0

Moura •

• Theodore

26°

28°

Mundubbera •

.Cracow

• Taroom

•Texas

a/A/sa6

50 100 km1 1

~ Westbourne Fm alone present Outcrop top of isopachedsequence

~Area of outcrop of isopached

Geological boundaryinterval

D Pilliga Sst replaces all or part -100- Isopach; interval 50 m... of other sequences

Data point

u..u. Erosional margin of isopachedsequence - PaMeocu"entdffecUon

Fig. 22. Thickness of Westboume Formati{)n and Springbok Sandstone.

36

148 0

Moura •

• Theodore

26°

28°

Mundubbera •

.Cracow

• Taroom

•Texas

a/A/sa6

50 100 km1 1

~ Westbourne Fm alone present Outcrop top of isopachedsequence

~Area of outcrop of isopached

Geological boundaryinterval

D Pilliga Sst replaces all or part -100- Isopach; interval 50 m... of other sequences

Data point

u..u. Erosional margin of isopachedsequence - PaMeocu"entdffecUon

Fig. 22. Thickness of Westboume Formati{)n and Springbok Sandstone.

37

.Cracow

Taroom

Q!A/581

~L:.....:..J

Area of outcrop of isopached interval

Hooray Sst replaces Gubberamunda Sst­Mooga Sst sequence

50 100 kmI j

...L.J W Erosional margin of isopached sequenceOutcrop top of isopached sequenceGeological boundary

-200- Isopach; interval 50 mData point

_ Palaeocurrent direction

Fig. 23. Thickness of Gubberamunda SandstonejMooga Sandstone interval.

37

.Cracow

Taroom

Q!A/581

~L:.....:..J

Area of outcrop of isopached interval

Hooray Sst replaces Gubberamunda Sst­Mooga Sst sequence

50 100 kmI j

...L.J W Erosional margin of isopached sequenceOutcrop top of isopached sequenceGeological boundary

-200- Isopach; interval 50 mData point

_ Palaeocurrent direction

Fig. 23. Thickness of Gubberamunda SandstonejMooga Sandstone interval.

38

100l.rn

f---------

Cecil Plains township

W PRESENT CAY

lOWl!'1 PaJOWOloic

Cretaceous

Jurassic

Tnassic

Carboniferous

LATE JURASSIC

, . y_>o,_<~.,,-,-, _ ' , ,=:t.ifii,.- --r-- ._.>-.-.._ . ....,.....- :.--.--=- -....-.----T-. '-'--

------- ~++Tnasslc+ + + + +

MlD .. JURASSIC Walloon Coal MeasuresLower JUnlSS1C

-- =--'-

Triassic~----1

.--_LA_T_E_TA_IA_S_S_'C -=~__=§~w~'~nd~o~'n~Fm~§:;:~~~C'~b'~w~m,;;Fm~~~~-----.:::~:.---c,~ ·-J~J.."A

;:: : : +\

EARL Y TRIASSICMid-Triassic

~ \/olcanics

'Jt.'¥ V /'I

~1+ + +_ + ,,~

Permo- Tnasslcgranite

- Manna Peffl'llan

.-. Oil and gas accumulations(,l/A/588

Fig, 24. Cross-sections showing evolution of Bowen and Surat Basins.

Triassic in the north. Deposition east of thetrough ceased as faulting and uplift began.Intrusion occurred east of the TaroomTrough from Carboniferous to Early Triassictime, with the loci of intrusion movingslowly eastward.

Surat BasinThe Early Jurassic land surface (Fig. 17)

consisted of elevated basement blocks inthe southwest, northeast (Auburn Arch andYarraman Block·) , and southeast (TexasHigh). Relatively low-lying areas included

the central plains underlain by Triassic sedi­ments, and an area east of the TaroomTrough underlain by Permo-CarboniferousvoIcanics and sediments.

Most of the low-lying areas were erodedonly during the period immediately beforedeposition began in the Surat Basin, as theywere soon covered by sand (Precipice Sand­stone); thereafter deposition spread steadilyover widening areas (Fig. 18).

The main source areas in the Jurassicwere: the southwestern block, composed of

38

100l.rn

f---------

Cecil Plains township

W PRESENT CAY

lOWl!'1 PaJOWOloic

Cretaceous

Jurassic

Tnassic

Carboniferous

LATE JURASSIC

, . y_>o,_<~.,,-,-, _ ' , ,=:t.ifii,.- --r-- ._.>-.-.._ . ....,.....- :.--.--=- -....-.----T-. '-'--

------- ~++Tnasslc+ + + + +

MlD .. JURASSIC Walloon Coal MeasuresLower JUnlSS1C

-- =--'-

Triassic~----1

.--_LA_T_E_TA_IA_S_S_'C -=~__=§~w~'~nd~o~'n~Fm~§:;:~~~C'~b'~w~m,;;Fm~~~~-----.:::~:.---c,~ ·-J~J.."A

;:: : : +\

EARL Y TRIASSICMid-Triassic

~ \/olcanics

'Jt.,¥ V /'I

~1+ + +_ + ,,~

Permo- Tnasslcgranite

- Manna Peffl'llan

.-. Oil and gas accumulations(,l/A/588

Fig, 24. Cross-sections showing evolution of Bowen and Surat Basins.

Triassic in the north. Deposition east of thetrough ceased as faulting and uplift began.Intrusion occurred east of the TaroomTrough from Carboniferous to Early Triassictime, with the loci of intrusion movingslowly eastward.

Surat BasinThe Early Jurassic land surface (Fig. 17)

consisted of elevated basement blocks inthe southwest, northeast (Auburn Arch andYarraman Block·) , and southeast (TexasHigh). Relatively low-lying areas included

the central plains underlain by Triassic sedi­ments, and an area east of the TaroomTrough underlain by Permo-CarboniferousvoIcanics and sediments.

Most of the low-lying areas were erodedonly during the period immediately beforedeposition began in the Surat Basin, as theywere soon covered by sand (Precipice Sand­stone); thereafter deposition spread steadilyover widening areas (Fig. 18).

The main source areas in the Jurassicwere: the southwestern block, composed of

·Cracow

• Texas

Q/A/602

39

~ Area of outcrop of isopached sequence

I:.:.:.:;::~d Bungil Fm absent

D Bungil Fm equivalent largely included inCadna-owie Fm (facies change)

50I

100 kmI

L.L.J U Erosional margin of isopached sequence

Outcrop top of isopached sequence

Geological boundary

-200- Isopach; interval 50 m

Data point

Fault

~ Pa~eocu"entd"ecUon

Fig. 25. Thickness of Bungil Formation and Doncaster Member.

·Cracow

• Texas

Q/A/602

39

~ Area of outcrop of isopached sequence

I:.:.:.:;::~d Bungil Fm absent

D Bungil Fm equivalent largely included inCadna-owie Fm (facies change)

50I

100 kmI

L.L.J U Erosional margin of isopached sequence

Outcrop top of isopached sequence

Geological boundary

-200- Isopach; interval 50 m

Data point

Fault

~ Pa~eocu"entd"ecUon

Fig. 25. Thickness of Bungil Formation and Doncaster Member.

40

Moura.

•

.Cracow

.Taroom

•

•

•

.-Q/A/589

............ Erosional margin (generallywithin 20 km of depositionalmargin)

50!

100 km!

- Fault

-- Isopach: interval 100 m

Fig. 26. Thickness of marine Cretaceous sequence.

J

40

Moura.

•

.Cracow

.Taroom

•

•

•

.-Q/A/589

............ Erosional margin (generallywithin 20 km of depositionalmargin)

50!

100 km!

- Fault

-- Isopach: interval 100 m

Fig. 26. Thickness of marine Cretaceous sequence.

J

siliceous sedimentary rocks, metasediments,schists, gneisses, and granites; the AuburnArch and Yarraman Block, consistinglargely of granite and gneiss; and the NewEngland Fold Belt, composed mainly ofindurated fine-grained sediments. Thesource areas for the marine Cretaceous sedi­ments were different because the southwest­ern basement block was no longer exposed,although the eastern blocks were, andbecause all the basinal sediments north ofRoma were being eroded. During the Cre­taceous andesitic volcanism farther east pro­vided most of the sediment laid down.

Major faulting and folding had ceased byearliest Jurassic time and, apart from slightmovement on older faults, the developmentof structures in the Jurassic and Cretaceouswas largely caused by draping over basementrises, and sinking of areas overlying thickPermo-Triassic sequences as they com­pacted.

Jurassic sedimentation was essentiallycyclic. The cycIothems are hundreds a'fmetres thick, and typical cycles generallybegan with coarse quartzose to sublabilesand, grading upwards into finer-grainedmore labile sand and silt, and ended withlabile sand, silt, mud, and some coal. Eachcycle represented deposition in turn frombraided streams, from meandering streams,and finally from swamps, lakes, and deltas.Marine influence appears to have been con­fined to the later stages of each cycle. Thecyclic deposition was related to periodicchanges in climatic, tectonic, or eustatic con­ditions. The maximum rate of sedimentationfor the Jurassic sequence was only 4 cmper 1000 years.

During the first cycle the Lower JurassicPrecipice Sandstone and Evergreen Forma­tion (Fig. 19) were laid down. The sandsin the lower part of the Precipice Sandstonewere deposited by a braided stream flowingto the southeast in the north (Mollan,Forbes, Jensen, Exon, & Gregory, 1972),and to the northeast in the south (Sell et al.,1972). The outlet to the system may havebeen to the north in the Cracow-Moura area,or to the cast through the Moreton Basinarea.

41

The porous and permeable lower part ofthe Precipice Sandstone, which is the mainpetroleum producer in the Surat Basin, isthickest (Fig. 20) where the total EvergreenFormation/Precipice Sandstone sequence(Fig. 19) is thickest. It is over 50 m thick inthe northwest and in the Mimosa Synclinenorth of Goondiwindi, and exceeds 100 min the northern part of the Mimosa Synclinearound Taroom. The fine-grained upper part,which was laid down by meandering streams,is generally thinner than the lower part, andthe total thickness of the Precipice Sand­stone does not exceed 150 m.

The Evergreen Formation transgressedfarther onto the basement blocks than theupper part of the Precipice Sandstone, whichitself had transgressed farther than the lowerpart (Figs 19,20).

The lower part of the Evergreen Forma­tion consists of stream sediments, but theupper part was partly marine. Thus the Box­vale Sandstone Member (Table 19), whichis underlain and overlain in places by bedscontaining swarms of acritarchs, may wellcontain marine beds. The finer-grained sand­stone facies of the Boxvale Sandstone Mem­ber probably represents beach sands. Theoverlying oolitic ironstone beds, which arcconfined to the northern part of the basinand which have counterparts in the MoretonBasin (Alien, 1971), have long beenregarded as marine.

In the second cycle of sedimentation, theLower Jurassic Hutton Sandstone and theMiddle Jurassic Walloon Coal Measureswere deposited. Depositional conditionswere less energetic than during the PrecipiceSandstone/Evergreen Formation cycle, withbraided streams relatively unimportant andcoal swamps much more important. TheHutton Sandstone, which contains excellentaquifers, transgressed far over the south­western basement block (Fig. 21) and wasoverlapped by the Walloon Coal Measuresboth in the southwest and southeast. Likcthe Precipice Sandstone/Evergreen Forma­tion interval, the sequence attains its maxi­mum thickness (Fig. 21) in the TaroomTrough and in the Moreton Basin. Most ofthe pre-Precipice Sandstone topographic

siliceous sedimentary rocks, metasediments,schists, gneisses, and granites; the AuburnArch and Yarraman Block, consistinglargely of granite and gneiss; and the NewEngland Fold Belt, composed mainly ofindurated fine-grained sediments. Thesource areas for the marine Cretaceous sedi­ments were different because the southwest­ern basement block was no longer exposed,although the eastern blocks were, andbecause all the basinal sediments north ofRoma were being eroded. During the Cre­taceous andesitic volcanism farther east pro­vided most of the sediment laid down.

Major faulting and folding had ceased byearliest Jurassic time and, apart from slightmovement on older faults, the developmentof structures in the Jurassic and Cretaceouswas largely caused by draping over basementrises, and sinking of areas overlying thickPermo-Triassic sequences as they com­pacted.

Jurassic sedimentation was essentiallycyclic. The cycIothems are hundreds a'fmetres thick, and typical cycles generallybegan with coarse quartzose to sublabilesand, grading upwards into finer-grainedmore labile sand and silt, and ended withlabile sand, silt, mud, and some coal. Eachcycle represented deposition in turn frombraided streams, from meandering streams,and finally from swamps, lakes, and deltas.Marine influence appears to have been con­fined to the later stages of each cycle. Thecyclic deposition was related to periodicchanges in climatic, tectonic, or eustatic con­ditions. The maximum rate of sedimentationfor the Jurassic sequence was only 4 cmper 1000 years.

During the first cycle the Lower JurassicPrecipice Sandstone and Evergreen Forma­tion (Fig. 19) were laid down. The sandsin the lower part of the Precipice Sandstonewere deposited by a braided stream flowingto the southeast in the north (Mollan,Forbes, Jensen, Exon, & Gregory, 1972),and to the northeast in the south (Sell et al.,1972). The outlet to the system may havebeen to the north in the Cracow-Moura area,or to the cast through the Moreton Basinarea.

41

The porous and permeable lower part ofthe Precipice Sandstone, which is the mainpetroleum producer in the Surat Basin, isthickest (Fig. 20) where the total EvergreenFormation/Precipice Sandstone sequence(Fig. 19) is thickest. It is over 50 m thick inthe northwest and in the Mimosa Synclinenorth of Goondiwindi, and exceeds 100 min the northern part of the Mimosa Synclinearound Taroom. The fine-grained upper part,which was laid down by meandering streams,is generally thinner than the lower part, andthe total thickness of the Precipice Sand­stone does not exceed 150 m.

The Evergreen Formation transgressedfarther onto the basement blocks than theupper part of the Precipice Sandstone, whichitself had transgressed farther than the lowerpart (Figs 19,20).

The lower part of the Evergreen Forma­tion consists of stream sediments, but theupper part was partly marine. Thus the Box­vale Sandstone Member (Table 19), whichis underlain and overlain in places by bedscontaining swarms of acritarchs, may wellcontain marine beds. The finer-grained sand­stone facies of the Boxvale Sandstone Mem­ber probably represents beach sands. Theoverlying oolitic ironstone beds, which arcconfined to the northern part of the basinand which have counterparts in the MoretonBasin (Alien, 1971), have long beenregarded as marine.

In the second cycle of sedimentation, theLower Jurassic Hutton Sandstone and theMiddle Jurassic Walloon Coal Measureswere deposited. Depositional conditionswere less energetic than during the PrecipiceSandstone/Evergreen Formation cycle, withbraided streams relatively unimportant andcoal swamps much more important. TheHutton Sandstone, which contains excellentaquifers, transgressed far over the south­western basement block (Fig. 21) and wasoverlapped by the Walloon Coal Measuresboth in the southwest and southeast. Likcthe Precipice Sandstone/Evergreen Forma­tion interval, the sequence attains its maxi­mum thickness (Fig. 21) in the TaroomTrough and in the Moreton Basin. Most ofthe pre-Precipice Sandstone topographic

42

irregularities had been smoothed out beforedeposition of the Hutton Sandstone began,and local variations in thickness arc there­fore smaller. The Walloon Coal Measuresvary much more in thickness than the Hut­ton Sandstone. The gradual uplift of theNebine Ridge is shown by the thinning ofthe Evergreen Formation, Hutton Sand­stone, and Walloon Coal Measures over it,in contrast to the Precipice Sandstone pat­tern.

The third cycle of sedimentation consistsof the Middle to Upper Jurassic SpringbokSandstone and Westbourne Formation,which intertongue with the Pilliga Sandstonein the south. The presence of considerableandesitic debris and bentonitic tuff in theSpringbok Sandstone and Westbourne For­mation, presumably derived from the northand east, indicates contemporaneous vol­canism. The Springbok Sandstone was depo­sited by meandering streams on coastalplains, and the Westbourne Formation waslaid down in backswamps, lakes, and deltas.The well sorted Pilliga Sandstone on theother hand was deposited by northerly-flow­ing braided streams. Although the variationin thickness of the sequence tends to parallelthat of the Hutton Sandstone/Walloon CoalMeasures interval, the range is much less(Fig. 22). The thinning towards the northand northwest indicates that uplift hadbegun in these areas. The Nebine Ridge per­sisted. The Dirranbandi Syncline had deve­loped into a prominent feature and was vir­tually cut off from the Mimosa Syncline by aridge between Roma and St George.

During the next sedimentary cycle theUpper Jurassic Gubberamunda Sandstoneand Orallo Formation were laid down to theeast of the Nebine Ridge. The Gubbera­munda Sandstone consists mainly of sanlsdeposited by braided and meanderingstreams, but the Orallo Formation consistsprincipally of finer-grained overbank andswamp deposits. Andesitic volcanismappears to have provided much of the debrisin the Orallo Formation, and bentonitic tuffis common.

The Orallo F0fmation is not present onthe Nebine Ridge, where the Mooga Sand-

stone rests directly on the GubberamundaSandstone. On the ridge it is not possible todistinguish between the Mooga and Gub­beramunda Sandstones, and the term HooraySandstone is used for the entire sequence.The thinning of the sequence to the northand east in Late Jurassic time (see Fig. 23)indicates epeirogenic uplift in these areas;the KumbariIla Ridge was an important fea­ture from then onward. The DirranbandiSyncline area remained a centre of deposi­tion.

The final cycle of deposition involved theLower Cretaceous Mooga Sandstone andBungil Formation. The Mooga Sandstonewas laid down by meandering streams andgrades upward into the Bungil Formation,which consists of fine-grained coastal plainand marginal marine deposits. The incomingof the sea in Neocomian and early Aptiantime ended the era of fluvial cycles.

To summarize the tectonic events (seeFig. 24), the decrease in the rate of subsi­dence of the Mimosa Syncline, the corres­ponding increase in importance of theDirranbandi Syncline, and the uplift of theNebine Ridge occurred in Middle Jurassictime, whereas uplift of the northern area andof the KumbariIla Ridge took place in LateJurassic time, mainly during the depositionof the Westbourne Formation. The wide­spread distribution of bentonitic tuffs in theMiddle and Upper Jurassic sequences of theSurat Basin (e.g. Exon, 1971; Swarbrick,1973) shows that this epeirogenic periodcoincided with a period of volcanism.

The general shape of the Surat Basin inthe Late Jurassic (Fig. 23) was similar tothat of the present-day basin (e.g. Fig. 10)with the southwesterly-trending depressionof the Dirranbandi Syncline superimposedon the meridional depression of the MimosaSyncline.

The Early Cretaceous marine transgres­sion, which began in the Neocomian with thedeposition of the Bungil Formation andended in the Albian with the Griman CreekFormation, was the last great sedimentaryepisode in the basin. The maximum rate ofdeposition for the entire period of 15 cm per1000 years was much higher than during

42

irregularities had been smoothed out beforedeposition of the Hutton Sandstone began,and local variations in thickness arc there­fore smaller. The Walloon Coal Measuresvary much more in thickness than the Hut­ton Sandstone. The gradual uplift of theNebine Ridge is shown by the thinning ofthe Evergreen Formation, Hutton Sand­stone, and Walloon Coal Measures over it,in contrast to the Precipice Sandstone pat­tern.

The third cycle of sedimentation consistsof the Middle to Upper Jurassic SpringbokSandstone and Westbourne Formation,which intertongue with the Pilliga Sandstonein the south. The presence of considerableandesitic debris and bentonitic tuff in theSpringbok Sandstone and Westbourne For­mation, presumably derived from the northand east, indicates contemporaneous vol­canism. The Springbok Sandstone was depo­sited by meandering streams on coastalplains, and the Westbourne Formation waslaid down in backswamps, lakes, and deltas.The well sorted Pilliga Sandstone on theother hand was deposited by northerly-flow­ing braided streams. Although the variationin thickness of the sequence tends to parallelthat of the Hutton Sandstone/Walloon CoalMeasures interval, the range is much less(Fig. 22). The thinning towards the northand northwest indicates that uplift hadbegun in these areas. The Nebine Ridge per­sisted. The Dirranbandi Syncline had deve­loped into a prominent feature and was vir­tually cut off from the Mimosa Syncline by aridge between Roma and St George.

During the next sedimentary cycle theUpper Jurassic Gubberamunda Sandstoneand Orallo Formation were laid down to theeast of the Nebine Ridge. The Gubbera­munda Sandstone consists mainly of sanlsdeposited by braided and meanderingstreams, but the Orallo Formation consistsprincipally of finer-grained overbank andswamp deposits. Andesitic volcanismappears to have provided much of the debrisin the Orallo Formation, and bentonitic tuffis common.

The Orallo F0fmation is not present onthe Nebine Ridge, where the Mooga Sand-

stone rests directly on the GubberamundaSandstone. On the ridge it is not possible todistinguish between the Mooga and Gub­beramunda Sandstones, and the term HooraySandstone is used for the entire sequence.The thinning of the sequence to the northand east in Late Jurassic time (see Fig. 23)indicates epeirogenic uplift in these areas;the KumbariIla Ridge was an important fea­ture from then onward. The DirranbandiSyncline area remained a centre of deposi­tion.

The final cycle of deposition involved theLower Cretaceous Mooga Sandstone andBungil Formation. The Mooga Sandstonewas laid down by meandering streams andgrades upward into the Bungil Formation,which consists of fine-grained coastal plainand marginal marine deposits. The incomingof the sea in Neocomian and early Aptiantime ended the era of fluvial cycles.

To summarize the tectonic events (seeFig. 24), the decrease in the rate of subsi­dence of the Mimosa Syncline, the corres­ponding increase in importance of theDirranbandi Syncline, and the uplift of theNebine Ridge occurred in Middle Jurassictime, whereas uplift of the northern area andof the KumbariIla Ridge took place in LateJurassic time, mainly during the depositionof the Westbourne Formation. The wide­spread distribution of bentonitic tuffs in theMiddle and Upper Jurassic sequences of theSurat Basin (e.g. Exon, 1971; Swarbrick,1973) shows that this epeirogenic periodcoincided with a period of volcanism.

The general shape of the Surat Basin inthe Late Jurassic (Fig. 23) was similar tothat of the present-day basin (e.g. Fig. 10)with the southwesterly-trending depressionof the Dirranbandi Syncline superimposedon the meridional depression of the MimosaSyncline.

The Early Cretaceous marine transgres­sion, which began in the Neocomian with thedeposition of the Bungil Formation andended in the Albian with the Griman CreekFormation, was the last great sedimentaryepisode in the basin. The maximum rate ofdeposition for the entire period of 15 cm per1000 years was much higher than during

the Jurassic. The accelerated deposition wasprobably due partly to active coastal ero­sion, but was due mainly to the vast increaseof stream-borne detritus derived from ande­sitic volcanic outbursts along the presenteast coast of Queensland.

The Cretaceous sea first entered the basinin late Neocomian time, when the paralicsediments of the Bungil Formation were laiddown. The sea deepened during depositionof the Aptian Doncaster Member, and theisopach map of the Bungil Formation/Don­caster Member interval (Fig. 25) shows thatthe greatest thickness of sediment accumu­lated in the southeast, and continued to doso throughout the whole period of marineCretaceous deposition (see Fig. 26). Thesea may have entered from the west over theNebine' Ridge, in which case the depressionto the east was rapidly inundated and deep­water marine muds were deposited almostdirectly on the freshwater sediments, exceptaround the margins of the basin. More pro­bably, the sea came first from the east viathe Moreton Basin, which was later uplifted;a seaway to the Gulf of Carpentaria wasformed in the Aptian.

In early Albian time there was a regres­sion (Coreena Member) foIlowed by an­other transgression (Surat Siltstone ). Thechange from a littoral to freshwater environ­ment in the Griman Creek Formation marksthe withdrawal of the sea in the middleAlbian.

During the Late Cretaceous and EarlyTertiary there was steady erosion and pedi­planation, and the development of a deep­weathering profile. In Oligocene-Miocenetimes basic volcanics were poured out to thenorth and east of the Surat Basin. The vol­canism was associated with epeirogenicmovements which increased the basinwardtilt first developed in the Late Jurassic.Thereafter, and until the present day, thebasin has been very stable, although as muchas 200 m of Cainozoic sediment is presentin places.

PETROLEUM GEOLOGYPetroleum exploration in the Surat Basin,

and the underlying Bowen Basin has a com­paratively long history and has been moder-

43

ately successful. An account of the earlyexploration, well histories, and drilling hasbeen compiled by the Geological Survey ofQueensland (1960), and later informationis available from a variety of sources as out­lined below.

Petroliferous gas was struck in aRomatown water bore in 1900-the first recordedhydrocarbon show in the basin. The Queens­land Government No. 2 water bore pro­duced gas for several years, and in 1906 agasometer was erected to supply Roma withgas; after 10 days the flow of gas suddenlystopped because of a blockage, and thescheme was abandoned. The srnall supplies,flooding and formation damage by water, andvarious technical difficulties hindered earlyexploration,

By 1960 44 exploration weIls had beendrilled in the Surat Basin, and 5 in theBowen Basin, but despite encouraging oiland gas shows, none was commercially im­portant; AAa No. 4 (Hospital Hill) struckgas in 1954, but this was not utilized until1961. Exploration had virtuaIly ceased by1960, but was renewed when Common­wealth assistance was introduced under thePetroleum Search Subsidy Act. The develop­ment of new geophysical techniques, in thisbasin where lack of outcrop had long beena problem for weIl-siting, also causedrenewed interest. The discovery of commer­cial gas at Pickanjinnie southeast of Roma,and subcommercial oil at Cabawin in theeastern part of the basin, both in 1961,further intensified exploration, and by 1965numerous srnall gas fields in the Roma areaand the Moonie and Alton Oil Fields hadbeen discovered. Thereafter new gas fieldswere found in the Roma area, but explorationelsewhere was generaIly unsuccessful. TheMoonie-Brisbane oil pipeline was completedfor Union-Kern-AOG in 1964, and theRoma-Brisbane gas pipeline for the Asso­ciated Group in 1969; in 1972 the capacityof the gas pipeline was increased to 34MMcf/d by the installation of a compressorat the start of the main transmission line.

By the end of 1973 some 375 explorationweIls had been drilled in the Surat Basin and32 in the Bowen Basin. For the Bowen and

the Jurassic. The accelerated deposition wasprobably due partly to active coastal ero­sion, but was due mainly to the vast increaseof stream-borne detritus derived from ande­sitic volcanic outbursts along the presenteast coast of Queensland.

The Cretaceous sea first entered the basinin late Neocomian time, when the paralicsediments of the Bungil Formation were laiddown. The sea deepened during depositionof the Aptian Doncaster Member, and theisopach map of the Bungil Formation/Don­caster Member interval (Fig. 25) shows thatthe greatest thickness of sediment accumu­lated in the southeast, and continued to doso throughout the whole period of marineCretaceous deposition (see Fig. 26). Thesea may have entered from the west over theNebine' Ridge, in which case the depressionto the east was rapidly inundated and deep­water marine muds were deposited almostdirectly on the freshwater sediments, exceptaround the margins of the basin. More pro­bably, the sea came first from the east viathe Moreton Basin, which was later uplifted;a seaway to the Gulf of Carpentaria wasformed in the Aptian.

In early Albian time there was a regres­sion (Coreena Member) foIlowed by an­other transgression (Surat Siltstone ). Thechange from a littoral to freshwater environ­ment in the Griman Creek Formation marksthe withdrawal of the sea in the middleAlbian.

During the Late Cretaceous and EarlyTertiary there was steady erosion and pedi­planation, and the development of a deep­weathering profile. In Oligocene-Miocenetimes basic volcanics were poured out to thenorth and east of the Surat Basin. The vol­canism was associated with epeirogenicmovements which increased the basinwardtilt first developed in the Late Jurassic.Thereafter, and until the present day, thebasin has been very stable, although as muchas 200 m of Cainozoic sediment is presentin places.

PETROLEUM GEOLOGYPetroleum exploration in the Surat Basin,

and the underlying Bowen Basin has a com­paratively long history and has been moder-

43

ately successful. An account of the earlyexploration, well histories, and drilling hasbeen compiled by the Geological Survey ofQueensland (1960), and later informationis available from a variety of sources as out­lined below.

Petroliferous gas was struck in aRomatown water bore in 1900-the first recordedhydrocarbon show in the basin. The Queens­land Government No. 2 water bore pro­duced gas for several years, and in 1906 agasometer was erected to supply Roma withgas; after 10 days the flow of gas suddenlystopped because of a blockage, and thescheme was abandoned. The srnall supplies,flooding and formation damage by water, andvarious technical difficulties hindered earlyexploration,

By 1960 44 exploration weIls had beendrilled in the Surat Basin, and 5 in theBowen Basin, but despite encouraging oiland gas shows, none was commercially im­portant; AAa No. 4 (Hospital Hill) struckgas in 1954, but this was not utilized until1961. Exploration had virtuaIly ceased by1960, but was renewed when Common­wealth assistance was introduced under thePetroleum Search Subsidy Act. The develop­ment of new geophysical techniques, in thisbasin where lack of outcrop had long beena problem for weIl-siting, also causedrenewed interest. The discovery of commer­cial gas at Pickanjinnie southeast of Roma,and subcommercial oil at Cabawin in theeastern part of the basin, both in 1961,further intensified exploration, and by 1965numerous srnall gas fields in the Roma areaand the Moonie and Alton Oil Fields hadbeen discovered. Thereafter new gas fieldswere found in the Roma area, but explorationelsewhere was generaIly unsuccessful. TheMoonie-Brisbane oil pipeline was completedfor Union-Kern-AOG in 1964, and theRoma-Brisbane gas pipeline for the Asso­ciated Group in 1969; in 1972 the capacityof the gas pipeline was increased to 34MMcf/d by the installation of a compressorat the start of the main transmission line.

By the end of 1973 some 375 explorationweIls had been drilled in the Surat Basin and32 in the Bowen Basin. For the Bowen and

44

TABLE 5. PROVED GAS RESERVES, SURAT BASIN(At end of 1973)

Initial RemainingYear Reservoir Recoverable Cumulative Recoverable

Field Discovered Reserves Production Reserves(millions m3 ) (millions m~) (millions m:l)

Hospital Hill 1954 Precipice Sst 3 I 2Timbury Hills 1960 Precipice Sst 105 34 71Pickanjinnie 1961 Precipice Sst & 1 337 176 161Showgrounds Sst \Bony Creek 1963 Precipice Sst 798 261 537Richmond 1963 Precipice Sst 385 176 209Back Creek 1964 Precipice Sst 11 1 10Beaufort 1964 Precipice Sst 116 1 115Blyth Creek 1964 Precipice Sst 52 52Duarran 1964 Precipice Sst 29 10 19Lamen 1964 Precipice Sst 44 44Raslie 1964 Precipice Sst 89 27 62Snake Creek 1964 Showgrounds Sst 57 37 20Yanalah 1964 Precipice Sst 169 9 160Maffra 1965 Precipice Sst 79 79

*Major 1965 Wandoan Fm 89 89Oberina 1965 Precipice Sst 54 54Pine Ridge 1965 Precipice Sst 181 35 146

Moolayember Fm 47 47Tarrawonga 1965 Precipice Sst & ) 137 75 62Showgrounds Sst \Lyndon Caves 1966 Precipice Sst 55 55Hope Creek 1967 Precipice Sst 67 67Pringle Downs 1967 Precipice Sst 17 2 15WaIlumbilla S 1967 Back Creek Gp 110 41 69Pleasant Hills 1968 Evergreen Fm.

Precipice Sst & f 941 153 788Showgrounds Sst JWestbourne Fm 14 14

Grafton Range 1969 Evergreen Fm & ) 354 58 296Precipice Sst J*Kincora 1969 Evergreen Fm & I 532 532Wandoan Fm \Mooga 1969 Precipice Sst 147 147

*Boxleigh 1970 Wandoan Fm 150 150EuthulIa 1970 Precipice Sst 156 156

*Noorindoo 1970 Blackwater Gp 111 111Westlartds 1970 Precipice Sst 27 27

Totals 5463 1097 4366

Note: All fields were discovered by Associated Group or Amalgamated Petroleum except those marked * whichwere discovered by Union Oil and associated companies south of Roma; the latter are a considerabledistance from the Roma-Brisbane pipeline.

Surat Basins initial reserves of oil (essen­tially the Alton and Moonie fields) were3.608 million ma, which had been depletedby 84 percent (3.026 million ma) by theend of 1973, and initial reserves of gas were5463 million ma, which have been depletedby 20 percent (l097 million ma) (seeTables 5, 6). Oil production at Moonie wasat the rate of 254 m 3 a day and at Alton44 m 3 a day, and gas production from theRoma fields was at the rate of 7.35 millionm 3 a day (,Petroleum Search in Australia'figures). More detailed statistics for the vari-

ous Surat Basin fields up to the end of 1973,taken from the records of the Department ofMines, Queensland (DMQ, 1973), are givenin Tables 5 and 6.

Table 5 shows the gas fields discoveredbetween 1954 and 1970, and that the bulkof the gas has yet to be exploited. Kincorais the only major field not held by theAsociated Group, but it is reasonably neartheir pipeline network.

Union Oil and its associates discoveredboth the Moonie and Alton Oil Fields, bothof which are nearing the ends of their com-

44

TABLE 5. PROVED GAS RESERVES, SURAT BASIN(At end of 1973)

Initial RemainingYear Reservoir Recoverable Cumulative Recoverable

Field Discovered Reserves Production Reserves(millions m3 ) (millions m~) (millions m:l)

Hospital Hill 1954 Precipice Sst 3 I 2Timbury Hills 1960 Precipice Sst 105 34 71Pickanjinnie 1961 Precipice Sst & 1 337 176 161Showgrounds Sst \Bony Creek 1963 Precipice Sst 798 261 537Richmond 1963 Precipice Sst 385 176 209Back Creek 1964 Precipice Sst 11 1 10Beaufort 1964 Precipice Sst 116 1 115Blyth Creek 1964 Precipice Sst 52 52Duarran 1964 Precipice Sst 29 10 19Lamen 1964 Precipice Sst 44 44Raslie 1964 Precipice Sst 89 27 62Snake Creek 1964 Showgrounds Sst 57 37 20Yanalah 1964 Precipice Sst 169 9 160Maffra 1965 Precipice Sst 79 79

*Major 1965 Wandoan Fm 89 89Oberina 1965 Precipice Sst 54 54Pine Ridge 1965 Precipice Sst 181 35 146

Moolayember Fm 47 47Tarrawonga 1965 Precipice Sst & ) 137 75 62Showgrounds Sst \Lyndon Caves 1966 Precipice Sst 55 55Hope Creek 1967 Precipice Sst 67 67Pringle Downs 1967 Precipice Sst 17 2 15WaIlumbilla S 1967 Back Creek Gp 110 41 69Pleasant Hills 1968 Evergreen Fm.

Precipice Sst & f 941 153 788Showgrounds Sst JWestbourne Fm 14 14

Grafton Range 1969 Evergreen Fm & ) 354 58 296Precipice Sst J*Kincora 1969 Evergreen Fm & I 532 532Wandoan Fm \Mooga 1969 Precipice Sst 147 147

*Boxleigh 1970 Wandoan Fm 150 150EuthulIa 1970 Precipice Sst 156 156

*Noorindoo 1970 Blackwater Gp 111 111Westlartds 1970 Precipice Sst 27 27

Totals 5463 1097 4366

Note: All fields were discovered by Associated Group or Amalgamated Petroleum except those marked * whichwere discovered by Union Oil and associated companies south of Roma; the latter are a considerabledistance from the Roma-Brisbane pipeline.

Surat Basins initial reserves of oil (essen­tially the Alton and Moonie fields) were3.608 million ma, which had been depletedby 84 percent (3.026 million ma) by theend of 1973, and initial reserves of gas were5463 million ma, which have been depletedby 20 percent (l097 million ma) (seeTables 5, 6). Oil production at Moonie wasat the rate of 254 m 3 a day and at Alton44 m 3 a day, and gas production from theRoma fields was at the rate of 7.35 millionm 3 a day (,Petroleum Search in Australia'figures). More detailed statistics for the vari-

ous Surat Basin fields up to the end of 1973,taken from the records of the Department ofMines, Queensland (DMQ, 1973), are givenin Tables 5 and 6.

Table 5 shows the gas fields discoveredbetween 1954 and 1970, and that the bulkof the gas has yet to be exploited. Kincorais the only major field not held by theAsociated Group, but it is reasonably neartheir pipeline network.

Union Oil and its associates discoveredboth the Moonie and Alton Oil Fields, bothof which are nearing the ends of their com-

45

TABLE 6. PROVED OIL RESERVES, SURAT BASIN(At end of 1973)

Initial Remaining

YearRecoverable Cumulative Recoverable

Field Discovered Reservoir Reserves Production Reserves(lOOOs m:J) (lOOOsm:J) (lOOOs m:J)

*Cabawin 1961 Blackwater Gp 115 115*Moonie 1961 Precipice Sst 2957 2746 211tRichmond 1963 Precipice Sst 14 2 12*Alton 1964 Evergreen Fm 305 259 46*Bennett 1965 Precipice Sst 105 13 92tTrinidad 1965 Precipice Sst 17 2 15*Boxleigh 1970 Wandoan Fm 52 52Other Roma fields* Various 43 4 40

Total 3608 3026 582

* Discovered by Union Oil and associated companies outside the Roma area.t Discovered by Associated Group or Amalgamated. Petroleum in the Roma area.

Note: Boxleigh is a condensate field.

mercial lives (Table 6). No substantial oilreserves have been discovered since 1965. In1972 International Oils Exploration N.L.acquired Union Oil's share of the Union­Kern-AOG consortium's interests in thearea.

By late 1974 the only area in the SuratBasin where major exploration was continu­ing was the Roma Shelf. Here the AssociatedGroup* was unsuccessfully drilling Permiantargets in the hope of finding major new gasreserves, as most of the obvious Jurassic tar­gets had already been drilled. The ratio ofsuccess on the Roma Shelf has been about20 percent for wildcat wells, and 40 percentfor development wells. Success ratios else­where have been very much lower.

Lists of exploration wells, with basicstatistics, are available in the publishedExplanatory Notes accompanying the1:250 000 Sheet areas. Annual lists are pro­vided by the Geological Survey of Queens­land (GSQ, 1960-64) and the Departmentof Mines, Queensland (DMQ, 1965-74).

Source rocksPossible petroleum source rocks include

the marine Carboniferous and Permiansequences, the Permian coal measures, theJurassic Evergreen Formation, and themarine Cretaceous sequence. The marine

Carboniferous sequence (distribution shownin Fig. 17) underlies the Bowen and SuratBasin sequences near all the eastern pet­roleum discoveries but had been folded, up­lifted, and eroded before deposition began inthe Bowen Basin. Any petroleum generatedwould have been carbonized or would haveescaped to the surface at that stage. Themarine Cretaceous sequence has yieldedtraces of petroleum (e.g. Galloway & Duff,1966), but generally insufficient depth ofburial to generate hydrocarbons (every­where less than 2000 m), and uncompli­cated up-dip connexion of the possible reser­voir sandstones to outcrop militate againstthe formation and trapping of oil. In anycase Cretaceous oil could not have con­tributed to the accumulations in the LowerJurassic and older rocks. Oil and gas wereprobably generated in both the Permiansequence and the Evergreen Formation, butthe relative importance of their contributionsto present-day accumulations is uncertain.

Several authors have considered themarine Permian sequence to be a potentialsource for petroleum in both the Permiansandstones and in younger reservoirs wherethey rest on the Permian. Recent papers sup­porting this view are those of Erickson(1965), Traves (1966), and Power (1967).

* The Associated Group consists of Associated Australian Resources NL (85%) and Interstate Oil Ltd(15%); the operational company is Mines Administration Pty Ltd.

45

TABLE 6. PROVED OIL RESERVES, SURAT BASIN(At end of 1973)

Initial Remaining

YearRecoverable Cumulative Recoverable

Field Discovered Reservoir Reserves Production Reserves(lOOOs m:J) (lOOOsm:J) (lOOOs m:J)

*Cabawin 1961 Blackwater Gp 115 115*Moonie 1961 Precipice Sst 2957 2746 211tRichmond 1963 Precipice Sst 14 2 12*Alton 1964 Evergreen Fm 305 259 46*Bennett 1965 Precipice Sst 105 13 92tTrinidad 1965 Precipice Sst 17 2 15*Boxleigh 1970 Wandoan Fm 52 52Other Roma fields* Various 43 4 40

Total 3608 3026 582

* Discovered by Union Oil and associated companies outside the Roma area.t Discovered by Associated Group or Amalgamated. Petroleum in the Roma area.

Note: Boxleigh is a condensate field.

mercial lives (Table 6). No substantial oilreserves have been discovered since 1965. In1972 International Oils Exploration N.L.acquired Union Oil's share of the Union­Kern-AOG consortium's interests in thearea.

By late 1974 the only area in the SuratBasin where major exploration was continu­ing was the Roma Shelf. Here the AssociatedGroup* was unsuccessfully drilling Permiantargets in the hope of finding major new gasreserves, as most of the obvious Jurassic tar­gets had already been drilled. The ratio ofsuccess on the Roma Shelf has been about20 percent for wildcat wells, and 40 percentfor development wells. Success ratios else­where have been very much lower.

Lists of exploration wells, with basicstatistics, are available in the publishedExplanatory Notes accompanying the1:250 000 Sheet areas. Annual lists are pro­vided by the Geological Survey of Queens­land (GSQ, 1960-64) and the Departmentof Mines, Queensland (DMQ, 1965-74).

Source rocksPossible petroleum source rocks include

the marine Carboniferous and Permiansequences, the Permian coal measures, theJurassic Evergreen Formation, and themarine Cretaceous sequence. The marine

Carboniferous sequence (distribution shownin Fig. 17) underlies the Bowen and SuratBasin sequences near all the eastern pet­roleum discoveries but had been folded, up­lifted, and eroded before deposition began inthe Bowen Basin. Any petroleum generatedwould have been carbonized or would haveescaped to the surface at that stage. Themarine Cretaceous sequence has yieldedtraces of petroleum (e.g. Galloway & Duff,1966), but generally insufficient depth ofburial to generate hydrocarbons (every­where less than 2000 m), and uncompli­cated up-dip connexion of the possible reser­voir sandstones to outcrop militate againstthe formation and trapping of oil. In anycase Cretaceous oil could not have con­tributed to the accumulations in the LowerJurassic and older rocks. Oil and gas wereprobably generated in both the Permiansequence and the Evergreen Formation, butthe relative importance of their contributionsto present-day accumulations is uncertain.

Several authors have considered themarine Permian sequence to be a potentialsource for petroleum in both the Permiansandstones and in younger reservoirs wherethey rest on the Permian. Recent papers sup­porting this view are those of Erickson(1965), Traves (1966), and Power (1967).

* The Associated Group consists of Associated Australian Resources NL (85%) and Interstate Oil Ltd(15%); the operational company is Mines Administration Pty Ltd.

46

TABLE 7. GEOTHERMAL GRADIENTS AND DEPTH OF POTENTIAL HYDROCARBONPRODUCTION

NumbnofDepth of Onset Depth of Onset

of Oil Production of Gas ProductionArea Water Bore Heat Flow in lnefres in metres

Readings (mrC) (95°C) (135°C)

Nebine Ridge 6 15-20 1200-1500 1800-2400Roma Shelf, andSt George-Bollon 30 20-30 1500-2300 2400-3500SlopeCentre andeastern margin of 6 30-40 2300-3100 3500-4700basin

Assumptions: (1) Mean surface air temperature = 20°C; (2) Mean surface rock temperature = 20°-3°C17°C; (3) Oil is produced predominantly in the range 95°-135°C, gas in the range 135°-150°C.

Certainly the organic-rich marine muds inthe Back Creek Group are suitable sourcerocks if historical factors were favourable.

Moran & Gussow (1963) have suggestedthat the Evergreen Formation, which is nowwidely regarded as partly marine, was asource of petroleum, because of the wide­spread shows within it, and because bubble­point pressures indicated Middle Jurassicaccumulation. De Jersey & AlIen (1966)have recorded Jurassic spores in oil from theJurassic, Triassic, and Permian reservoirs,and concluded that the Jurassic sequence wasthe only significant source of oil discoveredin the Surat and Bowen basins, although thePermian had yielded gas.

Recent geochemical studies have providednew data about the source of the petroleum.Mathews, Burns, & Johns (1971) studiedthe distribution of hydrocarbons in ninecrude oils from the Precipice Sandstone andthe Evergreen Formation in the Surat Basin,and also the distribution of hydrocarbons insolvent extracts from eight shale cores takenfrom strata adjacent to three of the oil reser­voirs. The distribution of n-alkanes in theshales (dominantly long-chain alkanes) weretypical of oils derived from land plants, butdiffered from the distribution in the oil reser­voirs (dominantly short-chain alkanes). Theauthors suggested that at least oils in theEvergreen Formation were derived from theformation itself, and that the differences indistributions of n-alkanes were due to dif­ferential adsorption on silicates (e.g. clays)during migration.

Powell & McKirdy (1972) studieCl the

chemistry of ten oils from the Bowen andSurat Basins. The samples were taken fromreservoirs ranging from Devonian to Jurassicin age, and in location from the Roma Shelfto Alton, Moonie, and Conloi. With theexception of the oil from UKA Conloi No.1, all the samples showed similarities incomposition in the fractions boiling above275°C, although the lower-boiling fractionsshowed considerable variation. The similar­ity in composition of the higher-boiling frac­tions suggests that they may have had asimilar source and that the differences incomposition of the lighter fractions were dueto alteration during migration. The Conloioil, which comes from within the EvergreenFormation, either had a different origin, orhad been extensively altered during migra­tion and incorporation in the reservoir.

Powell & McKirdy (1972, 1973) andothers have shown that the ratio of thestraight-chained alkanes, pristane and phy­tane, may indicate the origin of oils. Highpristane/phytane ratios are believed to indi­cate derivation from land plants becausehigh pristane values are favoured by aerobicdecomposition of plant material, which ismore likely on land. Partly decomposedmaterial would then be swept into a reduc­ing environment before oxidation was com­pleted and eventually give rise to hydrocar­bons. The rocks in which the organicmaterial was entombed could be non-marineor marine themselves.

The pristane/phytane ratios of the oilsfrom the Bowen and Surat Basins (generally5.6-8.2, Conloi 3.2; Powell & McKirdy,

46

TABLE 7. GEOTHERMAL GRADIENTS AND DEPTH OF POTENTIAL HYDROCARBONPRODUCTION

NumbnofDepth of Onset Depth of Onset

of Oil Production of Gas ProductionArea Water Bore Heat Flow in lnefres in metres

Readings (mrC) (95°C) (135°C)

Nebine Ridge 6 15-20 1200-1500 1800-2400Roma Shelf, andSt George-Bollon 30 20-30 1500-2300 2400-3500SlopeCentre andeastern margin of 6 30-40 2300-3100 3500-4700basin

Assumptions: (1) Mean surface air temperature = 20°C; (2) Mean surface rock temperature = 20°-3°C17°C; (3) Oil is produced predominantly in the range 95°-135°C, gas in the range 135°-150°C.

Certainly the organic-rich marine muds inthe Back Creek Group are suitable sourcerocks if historical factors were favourable.

Moran & Gussow (1963) have suggestedthat the Evergreen Formation, which is nowwidely regarded as partly marine, was asource of petroleum, because of the wide­spread shows within it, and because bubble­point pressures indicated Middle Jurassicaccumulation. De Jersey & AlIen (1966)have recorded Jurassic spores in oil from theJurassic, Triassic, and Permian reservoirs,and concluded that the Jurassic sequence wasthe only significant source of oil discoveredin the Surat and Bowen basins, although thePermian had yielded gas.

Recent geochemical studies have providednew data about the source of the petroleum.Mathews, Burns, & Johns (1971) studiedthe distribution of hydrocarbons in ninecrude oils from the Precipice Sandstone andthe Evergreen Formation in the Surat Basin,and also the distribution of hydrocarbons insolvent extracts from eight shale cores takenfrom strata adjacent to three of the oil reser­voirs. The distribution of n-alkanes in theshales (dominantly long-chain alkanes) weretypical of oils derived from land plants, butdiffered from the distribution in the oil reser­voirs (dominantly short-chain alkanes). Theauthors suggested that at least oils in theEvergreen Formation were derived from theformation itself, and that the differences indistributions of n-alkanes were due to dif­ferential adsorption on silicates (e.g. clays)during migration.

Powell & McKirdy (1972) studieCl the

chemistry of ten oils from the Bowen andSurat Basins. The samples were taken fromreservoirs ranging from Devonian to Jurassicin age, and in location from the Roma Shelfto Alton, Moonie, and Conloi. With theexception of the oil from UKA Conloi No.1, all the samples showed similarities incomposition in the fractions boiling above275°C, although the lower-boiling fractionsshowed considerable variation. The similar­ity in composition of the higher-boiling frac­tions suggests that they may have had asimilar source and that the differences incomposition of the lighter fractions were dueto alteration during migration. The Conloioil, which comes from within the EvergreenFormation, either had a different origin, orhad been extensively altered during migra­tion and incorporation in the reservoir.

Powell & McKirdy (1972, 1973) andothers have shown that the ratio of thestraight-chained alkanes, pristane and phy­tane, may indicate the origin of oils. Highpristane/phytane ratios are believed to indi­cate derivation from land plants becausehigh pristane values are favoured by aerobicdecomposition of plant material, which ismore likely on land. Partly decomposedmaterial would then be swept into a reduc­ing environment before oxidation was com­pleted and eventually give rise to hydrocar­bons. The rocks in which the organicmaterial was entombed could be non-marineor marine themselves.

The pristane/phytane ratios of the oilsfrom the Bowen and Surat Basins (generally5.6-8.2, Conloi 3.2; Powell & McKirdy,

1972) are much higher than those recordedin a number of overseas oils which areregarded as marine (Powell & McKirdy,1973). This strongly suggests that they arederived from land plants. Abundant plantmaterial is preserved in the fine-grainedrocks in both the Permian sequence and theEvergreen Formation (which include bothnon-marine and marine sediments), so theoil could have been derived from either.

Present-day geothermal gradients in 42subartesian water bores in the Surat Basinhave been calculated by Dr E. Polak (pers.comm. ). The results are summarized inTable 7, which shows high gradients on theNebine Ridge, moderate gradients on theRoma Shelf and the St George/BollonSlope, and low gradients in the central andeastern parts of the basin.

Using certain widely accepted assumptions(Table 7), the depth of onset of oil produc­tion in these areas at present would liebetween 1200 m on parts of the NebineRidge, and 3100 m in parts of the easternside of the basin. As the area has been tec­tonically stable since the Triassic, thesefigures may well have applied since then, andpossibly indicate the amount of cover neces­sary to develop oil and gas in the EvergreenFormation. In combination with the variousisopach maps they suggest that developmentand migration of petroleum from the Ever­green Formation was unlikely until Creta­ceous time in most of the basin.

Migration and entrapmentThe regional directions of lateral migra­

tion of hydrocarbons at different periods inthe history of the basin were outlined byErickson (1965), and the present discus­sion and results, based on more detailedmaps, are broadly similar. Erickson believedthat major eastward migration could havestarted in the Early Triassic, whereas thepresent study suggests that it began in theMiddle Triassic. He assumed that there werehydrocarbons and that 'they would migratein an updip direction for some distance,often in spite of a very low dip'. He did notdeal with 'less tangible factors such as thenature of migration, the time of lithification,the tendency of porosity to decrease basin-

47

wards, the timing of the earliest compactionand flushing of clays, etc.' It has here beenassumed that a depth of cover of 2000 m issufficient to generate hydrocarbons and starttheir migration.

The present study makes the sameassumptions and uses the same methods asErickson, who stated that 'the direction ofregional migration is traced through geo­logical time by making use of a series of iso­pach maps. If the upper marker bed isregarded as an approximate datum plane,the isopach contours become a structuralmap of the lower marker bed at the time theupper one was deposited. The degree ofstructural flexing of sedimentary bedsbetween the marker beds increases graduallyfrom the top to the bottom of the section in­volved. The direction of hydrocarbon migra­tion is towards the thin areas shown on theisopach maps. The chosen direction ofmigration can be no better than the maps,and these in turn are no better than themarkers themselves, which, of course,seldom formed a horizontal datum, or mayhave been subsequently subjected to ero­sion.'

Isopachs of the intervals of most interestare presented in Figure 27. The oldest sedi­ments belong to the mainly Lower PermianBack Creek Group, and include a number offossiliferous limestones, sandstones, silt­stones, and mudstones. Regressive sandbodies such as the Catherine Sandstone,which yielded gas at Rolleston, are the onlylikely reservoir rocks. The isopachs (Fig.27a) show that the sequence near Taroomis about 4000 m thick, and that it thinssteadily to the west and south. The westernlimit is considered to be a depositionaledge, and the eastern limit is erosionaland faulted. The main directions of lateralmigration are shown in Figure 27a. At theend of deposition of the group the dominantdirection was southwesterlv; the base of thegroup rose at about 40 ~ per km in thenorth, and at about 15 m per km in thesouth. Mack (1963) reported depositionalthinning over the Cabawin Anticline, whichwould ~have directed local migration intothat area.

1972) are much higher than those recordedin a number of overseas oils which areregarded as marine (Powell & McKirdy,1973). This strongly suggests that they arederived from land plants. Abundant plantmaterial is preserved in the fine-grainedrocks in both the Permian sequence and theEvergreen Formation (which include bothnon-marine and marine sediments), so theoil could have been derived from either.

Present-day geothermal gradients in 42subartesian water bores in the Surat Basinhave been calculated by Dr E. Polak (pers.comm. ). The results are summarized inTable 7, which shows high gradients on theNebine Ridge, moderate gradients on theRoma Shelf and the St George/BollonSlope, and low gradients in the central andeastern parts of the basin.

Using certain widely accepted assumptions(Table 7), the depth of onset of oil produc­tion in these areas at present would liebetween 1200 m on parts of the NebineRidge, and 3100 m in parts of the easternside of the basin. As the area has been tec­tonically stable since the Triassic, thesefigures may well have applied since then, andpossibly indicate the amount of cover neces­sary to develop oil and gas in the EvergreenFormation. In combination with the variousisopach maps they suggest that developmentand migration of petroleum from the Ever­green Formation was unlikely until Creta­ceous time in most of the basin.

Migration and entrapmentThe regional directions of lateral migra­

tion of hydrocarbons at different periods inthe history of the basin were outlined byErickson (1965), and the present discus­sion and results, based on more detailedmaps, are broadly similar. Erickson believedthat major eastward migration could havestarted in the Early Triassic, whereas thepresent study suggests that it began in theMiddle Triassic. He assumed that there werehydrocarbons and that 'they would migratein an updip direction for some distance,often in spite of a very low dip'. He did notdeal with 'less tangible factors such as thenature of migration, the time of lithification,the tendency of porosity to decrease basin-

47

wards, the timing of the earliest compactionand flushing of clays, etc.' It has here beenassumed that a depth of cover of 2000 m issufficient to generate hydrocarbons and starttheir migration.

The present study makes the sameassumptions and uses the same methods asErickson, who stated that 'the direction ofregional migration is traced through geo­logical time by making use of a series of iso­pach maps. If the upper marker bed isregarded as an approximate datum plane,the isopach contours become a structuralmap of the lower marker bed at the time theupper one was deposited. The degree ofstructural flexing of sedimentary bedsbetween the marker beds increases graduallyfrom the top to the bottom of the section in­volved. The direction of hydrocarbon migra­tion is towards the thin areas shown on theisopach maps. The chosen direction ofmigration can be no better than the maps,and these in turn are no better than themarkers themselves, which, of course,seldom formed a horizontal datum, or mayhave been subsequently subjected to ero­sion.'

Isopachs of the intervals of most interestare presented in Figure 27. The oldest sedi­ments belong to the mainly Lower PermianBack Creek Group, and include a number offossiliferous limestones, sandstones, silt­stones, and mudstones. Regressive sandbodies such as the Catherine Sandstone,which yielded gas at Rolleston, are the onlylikely reservoir rocks. The isopachs (Fig.27a) show that the sequence near Taroomis about 4000 m thick, and that it thinssteadily to the west and south. The westernlimit is considered to be a depositionaledge, and the eastern limit is erosionaland faulted. The main directions of lateralmigration are shown in Figure 27a. At theend of deposition of the group the dominantdirection was southwesterlv; the base of thegroup rose at about 40 ~ per km in thenorth, and at about 15 m per km in thesouth. Mack (1963) reported depositionalthinning over the Cabawin Anticline, whichwould ~have directed local migration intothat area.

;\0 100 150 200 km

(d)

(b)

WANOOAN ISOPACHS

BLACKWATER ISOPACHS

PRESENT-OAY STRUCTURE ON TOP OF THE WAllOON

(c)

(a)

,.\I\\

\\\II\I....,

\\I,\BACK CREEK ISOPACHS

48

Fig. 27. Petroleum migration routes.

~.:::.. ::~

~

Extent of the Precipice andHelidon Sandstone

Outcrop of sequence considered

Possible migration direction withslope in metres per kilometre

Petroleum fields

;\0 100 150 200 km

(d)

(b)

WANOOAN ISOPACHS

BLACKWATER ISOPACHS

PRESENT-OAY STRUCTURE ON TOP OF THE WAllOON

(c)

(a)

,.\I\\

\\\II\I....,

\\I,\BACK CREEK ISOPACHS

48

Fig. 27. Petroleum migration routes.

~.:::.. ::~

~

Extent of the Precipice andHelidon Sandstone

Outcrop of sequence considered

Possible migration direction withslope in metres per kilometre

Petroleum fields

The Upper Permian Blackwater Groupconsists of non-marine lithic sandstone, silt­stone, mudstone, and coal. No reservoirrocks are known within the group. The iso­pachs (Fig. 27b) show that the depositionaland migrational patterns were similar tothose of the Back Creek Group. Afterdeposition of the Blackwater Group the baseof the group rose at 3 to 6 m per km,generally to the west-southwest. Althoughhydrocarbons in the Blackwater Groupwould not have migrated at that stage,because the maximum thickness of the groupis 700 m, any hydrocarbons in the middle ofthe Back Creek Group would probablyhave started to migrate.

The Lower Triassic Rewan Group, whichis up to 4000 m thick (Fig. 27c) is a redbedsequence consisting of mudstone, lithic sand­stone, and some conglomerate, especially inthe Cabawin Formation. It contains noknown source rocks or reservoirs. Duringthe Early Triassic the eastern margin of thepresent-day Taroom Trough developed inthe south with uplift of basement blocksalong meridional faults; the Cabawin Forma­tion consists of coarse detritus laid down inthe newly formed basin. Changes in theshape of the basin led to some changes indirection of migration. When deposition ofthe Rewan Group had been completed thebase of the group rose to the west-southwestat 50 m per km in the north and at 25 mper km in the south, and to the southeast at15 m per km in the south; in the northeastan easterly component of migration mayhave started to develop. Most of the hydro­carbons from the Permian strata would havebegun to migrate by the end of RewanGroup time. Some would have been trappedin Permian reservoirs, some would havebeen hindered in their migration by thenumerous impermeable beds, and somewould have escaped at the surface.

The mainly Middle Triassic WandoanFormation, which is up to 2000 m thick(Fig. 27d), consists mainly of labile sand­stone, siltstone, and mudstone, but the lowerpart contains quartzose sandstones whichform reservoirs and potential reservoirs(Showgrounds and Clematis Sandstones ).

49

During the Middle Triassic the eastern mar­gin of the Taroom Trough took up itsmodern configuration when uplift of thebasement in the northeast was completed. Bythe time deposition of the Wandoan Forma­tion had been completed, an easterly migra­tion direction was firmly established in theeast, where the base of the formation roseat 13 to 20 m per km. After deposition ofthe Wandoan Formation there was a longperiod of erosion and peneplanation.

By the Late Triassic the maximum load­ing on the potential source rocks of the Per­mian sequenee was over 5000 m in thenorth, but less than 200 m west of Moonie.The sequence had been compressed and sub­jected to most of the tectonic movementwhich has occurred in the basin. Migrationmust have occurred from source rocks inmost of the basin, but perhaps not in thesouth. Hydrocarbons were probably trappedin sandstones in the Back Creek Group atRolleston and possibly in the ShowgroundsSandstone on the Roma Shelf. Considerablequantities of hydrocarbons must haveescaped to the surface, especially along theeastern margin where the upturned Permianbeds crop out extensively.

The main producer of hydrocarbons in thebasin, the Lower Jurassic Precipice Sand­stone, was now laid down unconformably onthe older sediments. The porous and per­meable lower part of the quartzose PrecipiceSandstone is thickest in the north and east,but its distribution in the south and west ispatchy (Fig. 20). The inter-relationship ofthe underlying units and the units resting onthe unconformity surface (of which the mostimportant is the Precipice Sandstone) isshown by the palaeogeological maps (Figs17, 18). The Precipice Sandstone restsdirectly on all the older units along theeastern margin of the basin, and on theBack Creek Group in the southern part ofthe Comet Platform, but elsewhere itgenerally overlies the Wandoan Formation.To be found anywhere in the Jurassicsequence, hydrocarbons from Permian sourcerocks would, in almost all areas, have hadfirst to make their way into the PrecipiceSandstone.

The Upper Permian Blackwater Groupconsists of non-marine lithic sandstone, silt­stone, mudstone, and coal. No reservoirrocks are known within the group. The iso­pachs (Fig. 27b) show that the depositionaland migrational patterns were similar tothose of the Back Creek Group. Afterdeposition of the Blackwater Group the baseof the group rose at 3 to 6 m per km,generally to the west-southwest. Althoughhydrocarbons in the Blackwater Groupwould not have migrated at that stage,because the maximum thickness of the groupis 700 m, any hydrocarbons in the middle ofthe Back Creek Group would probablyhave started to migrate.

The Lower Triassic Rewan Group, whichis up to 4000 m thick (Fig. 27c) is a redbedsequence consisting of mudstone, lithic sand­stone, and some conglomerate, especially inthe Cabawin Formation. It contains noknown source rocks or reservoirs. Duringthe Early Triassic the eastern margin of thepresent-day Taroom Trough developed inthe south with uplift of basement blocksalong meridional faults; the Cabawin Forma­tion consists of coarse detritus laid down inthe newly formed basin. Changes in theshape of the basin led to some changes indirection of migration. When deposition ofthe Rewan Group had been completed thebase of the group rose to the west-southwestat 50 m per km in the north and at 25 mper km in the south, and to the southeast at15 m per km in the south; in the northeastan easterly component of migration mayhave started to develop. Most of the hydro­carbons from the Permian strata would havebegun to migrate by the end of RewanGroup time. Some would have been trappedin Permian reservoirs, some would havebeen hindered in their migration by thenumerous impermeable beds, and somewould have escaped at the surface.

The mainly Middle Triassic WandoanFormation, which is up to 2000 m thick(Fig. 27d), consists mainly of labile sand­stone, siltstone, and mudstone, but the lowerpart contains quartzose sandstones whichform reservoirs and potential reservoirs(Showgrounds and Clematis Sandstones ).

49

During the Middle Triassic the eastern mar­gin of the Taroom Trough took up itsmodern configuration when uplift of thebasement in the northeast was completed. Bythe time deposition of the Wandoan Forma­tion had been completed, an easterly migra­tion direction was firmly established in theeast, where the base of the formation roseat 13 to 20 m per km. After deposition ofthe Wandoan Formation there was a longperiod of erosion and peneplanation.

By the Late Triassic the maximum load­ing on the potential source rocks of the Per­mian sequenee was over 5000 m in thenorth, but less than 200 m west of Moonie.The sequence had been compressed and sub­jected to most of the tectonic movementwhich has occurred in the basin. Migrationmust have occurred from source rocks inmost of the basin, but perhaps not in thesouth. Hydrocarbons were probably trappedin sandstones in the Back Creek Group atRolleston and possibly in the ShowgroundsSandstone on the Roma Shelf. Considerablequantities of hydrocarbons must haveescaped to the surface, especially along theeastern margin where the upturned Permianbeds crop out extensively.

The main producer of hydrocarbons in thebasin, the Lower Jurassic Precipice Sand­stone, was now laid down unconformably onthe older sediments. The porous and per­meable lower part of the quartzose PrecipiceSandstone is thickest in the north and east,but its distribution in the south and west ispatchy (Fig. 20). The inter-relationship ofthe underlying units and the units resting onthe unconformity surface (of which the mostimportant is the Precipice Sandstone) isshown by the palaeogeological maps (Figs17, 18). The Precipice Sandstone restsdirectly on all the older units along theeastern margin of the basin, and on theBack Creek Group in the southern part ofthe Comet Platform, but elsewhere itgenerally overlies the Wandoan Formation.To be found anywhere in the Jurassicsequence, hydrocarbons from Permian sourcerocks would, in almost all areas, have hadfirst to make their way into the PrecipiceSandstone.

50

During the Jurassic the basin was com­paratively stable and each unit generallylapped over the previous one onto basement.Overlying the Precipice Sandstone is theEvergreen Formation, which consists mainlyof mudstone, siltstone, and labile sandstone,but which also contains the quartzose Box­vale Sandstone that is a reservoir in somefields. The quartzose Hutton Sandstoneabove the Evergreen Formation is anotherpotential reservoir. The Middle JurassicWalloon Coal Measures, which consist ofmudstone, siltstone, labile sandstone, andcoal, overlapped the Hutton Sandstone inmost of the basin, and formed an effectivecap that would have prevented the escape ofhydrocarbons from the older units in mostareas. The Evergreen Formation is theyoungest probable source rock for thehydrocarbons in the basin, so in most areasrocks younger than the Hutton Sandstoneare unlikely to contain economic accumula­tions and they are therefore not discussedhere.

By the end of the Walloon Coal Measurestime, as much as 1000 m of Jurassic sedi­ment had accumulated, not enough to freehydrocarbons in the Evergreen Formation,but enough to promote further migration ofhydrocarbons in the pre-Jurassic rocks.Hydrocarbons could have moved into thePrecipice Sandstone directly from the Per­mian and Triassic sequences along theeastern side of the basin, and on the southernpart of the Comet Platform. Along thewestern margin of the basin, hydrocarbonscould have migrated along the basal sandsat the contact between the generally tightWandoan Formation and the basementrocks, and up into the Precipice Sandstone.

After deposition of the Walloon CoalMeasures had been completed, the slope onthe lower Precipice Sandstone was still onlybetween 4 and 8 m per km (Fig. 27e).Hydrocarbons escaping into the PrecipiceSandstone along the eastern margin of theTaroom Trough would have either madetheir way southeastward in the south, wherethe Walloon Coal Measures seal wasprobably incomplete and they may haveescaped to the surface, or have remained

more or less in place in the north. Hydro­carbons escaping from the Permian rocks inthe southern part of the Comet Platformwould have migrated southwestward acrossthe Roma Shelf. Hydrocarbons escapingalong the southwestern edge of the WandoanFormation would have entered either thefringe of the Precipice Sandstone, or theEvergreen Formation and, by movingthrough the sands resting on basement,could have moved up into the Hutton Sand­stone and thence southwestward into theBollon area, where they would have beentrapped against the basement rise by theoverlapping Walloon Coal Measures.

Structural and porosity/permeability trapsin the Precipice Sandstone would have pre­vented extensive lateral migration of largequantities of hydrocarbons in many areas­especially along the eastern faulted zone,and on the Roma Shelf.

In summary, the only hydrocarbons likelyto have been migrating until the MiddleJurassic would have been from the Permiansequence. Until the Middle Triassic migra­tion would have been dominantly to thesoutheast and southwest and west. There­after migration would have been to thesoutheast and southwest towards the sidesof the basin. The bulk of the hydro­carbons would have started to migrate in theEarly Triassic and would thereafter havebeen committed to a southwesterly course.Most of the hydrocarbons which did migrateto the east in the Late Triassic would haveescaped at the surface. Thus in the MiddleJurassic hydrocarbons would have been con­centrated in Permian, Triassic, and LowerJurassic reservoirs, mainly on the westernside of the basin.

Later in the Jurassic, epeirogenic uplift inthe north and east gave the basin its modernshape, and the migration directions shown inFigure 27f were established. Tertiary epeiro­genic uplift in the same areas resulted in anincrease in the tilt along the migration direc­tions, which are now 3 to 15 m per km onthe top of the Walloon Coal Measures, andsomewhat more on the Precipice Sandstone.

The isopach map of the total Jurassicsequence (PI. 21) suggests that it was not

50

During the Jurassic the basin was com­paratively stable and each unit generallylapped over the previous one onto basement.Overlying the Precipice Sandstone is theEvergreen Formation, which consists mainlyof mudstone, siltstone, and labile sandstone,but which also contains the quartzose Box­vale Sandstone that is a reservoir in somefields. The quartzose Hutton Sandstoneabove the Evergreen Formation is anotherpotential reservoir. The Middle JurassicWalloon Coal Measures, which consist ofmudstone, siltstone, labile sandstone, andcoal, overlapped the Hutton Sandstone inmost of the basin, and formed an effectivecap that would have prevented the escape ofhydrocarbons from the older units in mostareas. The Evergreen Formation is theyoungest probable source rock for thehydrocarbons in the basin, so in most areasrocks younger than the Hutton Sandstoneare unlikely to contain economic accumula­tions and they are therefore not discussedhere.

By the end of the Walloon Coal Measurestime, as much as 1000 m of Jurassic sedi­ment had accumulated, not enough to freehydrocarbons in the Evergreen Formation,but enough to promote further migration ofhydrocarbons in the pre-Jurassic rocks.Hydrocarbons could have moved into thePrecipice Sandstone directly from the Per­mian and Triassic sequences along theeastern side of the basin, and on the southernpart of the Comet Platform. Along thewestern margin of the basin, hydrocarbonscould have migrated along the basal sandsat the contact between the generally tightWandoan Formation and the basementrocks, and up into the Precipice Sandstone.

After deposition of the Walloon CoalMeasures had been completed, the slope onthe lower Precipice Sandstone was still onlybetween 4 and 8 m per km (Fig. 27e).Hydrocarbons escaping into the PrecipiceSandstone along the eastern margin of theTaroom Trough would have either madetheir way southeastward in the south, wherethe Walloon Coal Measures seal wasprobably incomplete and they may haveescaped to the surface, or have remained

more or less in place in the north. Hydro­carbons escaping from the Permian rocks inthe southern part of the Comet Platformwould have migrated southwestward acrossthe Roma Shelf. Hydrocarbons escapingalong the southwestern edge of the WandoanFormation would have entered either thefringe of the Precipice Sandstone, or theEvergreen Formation and, by movingthrough the sands resting on basement,could have moved up into the Hutton Sand­stone and thence southwestward into theBollon area, where they would have beentrapped against the basement rise by theoverlapping Walloon Coal Measures.

Structural and porosity/permeability trapsin the Precipice Sandstone would have pre­vented extensive lateral migration of largequantities of hydrocarbons in many areas­especially along the eastern faulted zone,and on the Roma Shelf.

In summary, the only hydrocarbons likelyto have been migrating until the MiddleJurassic would have been from the Permiansequence. Until the Middle Triassic migra­tion would have been dominantly to thesoutheast and southwest and west. There­after migration would have been to thesoutheast and southwest towards the sidesof the basin. The bulk of the hydro­carbons would have started to migrate in theEarly Triassic and would thereafter havebeen committed to a southwesterly course.Most of the hydrocarbons which did migrateto the east in the Late Triassic would haveescaped at the surface. Thus in the MiddleJurassic hydrocarbons would have been con­centrated in Permian, Triassic, and LowerJurassic reservoirs, mainly on the westernside of the basin.

Later in the Jurassic, epeirogenic uplift inthe north and east gave the basin its modernshape, and the migration directions shown inFigure 27f were established. Tertiary epeiro­genic uplift in the same areas resulted in anincrease in the tilt along the migration direc­tions, which are now 3 to 15 m per km onthe top of the Walloon Coal Measures, andsomewhat more on the Precipice Sandstone.

The isopach map of the total Jurassicsequence (PI. 21) suggests that it was not

51

149°15'149"00'

500

400

800-__...-'\

SUE Ni.II. North w..t 1p ;:f/ARO 7' I~ / I ",-./ /p

( -:-:-:: " \ t<' -,....... End GI.nora 1

o'AAO Mt B.agl. 1 AAO N"II. 1/$ ~ "" I j~

AAO NI.II. Ia J ": l\ //'\ \0'17 13 1~ 4 I

/'160', 1!l.. 10, /" 4", 16 1 / IAAO Tab.rs l:t AAO Ourb;;; 1 (I;l:~ 5 P 18 ..... ~.>' ' P End GI.na... 1;:.'A~ /-p4 AAO 1~8/$1~1B'" 4 ~~ 17.er AAOMtHop.-SOO //(

,,~ ....p'3 141, l' 1 11) \3~~ ~ 'of I ( /AAO'~I /$3 AAO~GRI\ 9~N~a/B'IO"1~Jb!~O ~O'd'I';U"1 \f;dJavoll /

WESTlANDS /$4 MOOGA ..:ifl At?1 \5p':~ GAlS" 5r dB \" J '" I/ i;l'RANG 6 PlEASA~T-!illlS \

AAO OUlb" I"" ( ~131 '" \ AAO SI..,y Cre.k I / --..~ I~AR011 3 Y ,_" " P7 13P: f~ I 1,,'P;':"'). J14 ~ /$AAO Wy... 1

/. 4p I~1, /$AAO HaVlnoton 1 ,,- ":1.4 /. AAO RASlIE I IAAO \A~03 pRBO 2 \ gl~ .... -LJ'!r:t 4:)" /

EUTHUllA'&, \gg228~ .1-", AV~lp'1 f 11d/O 1 '$ ,~!$ /AR013 \ (? RB04 .erRBO 3 AAO Wrn"on I ;:; 30 Ps ( AAO Sawpl! er.. 1

r _ AAO Mrnh 1.er \ AAO Mrnml lp' P'AAO Yan.l.h 1 \ p' ~Ro14 P.l.er / - 'v/ ....... ,/ / ",:--, --__ ~- / 1,0 ,,/SUE Wanoary North lp' /-' ~ T r""'l \ 0 Yonalah 1 -.-/ -..~ /,0 :\'Y ,/

I d AAO Inun ) \ Jf ~ AAO St8keyard 1 /......\ AAO W..oary 1 / It, _ AO y..~I.h 3 AAO Blythesdal.~rth)'<~ \..J t:! _/%'./

-'AO \ / AA06\ROM oTimburyHiII,2. ~AAO,Wa1t ..ooka J '"/AI HOdolon~ ,~_ .•dOSl1 AR08/ .r- P __./Jf AAO \ ' :to 4 ...AOli 'J ~- R?C4~R05 AAO Bore Vi.w 1 5 r£J1 ~

1~~ ROg.3.4 f> '" A -l.~~ (~iR04 r-- 4___ 9 DD/ lAOl4 'j:f- EA FOR :,iI'AJlOll AAO lat.more 1 :I'< '1 1/$-9

/ ,A Rom. South 1 --.. AAIl.Worooby South 1 -CJ:;' 1* 1R019. __ ...... - ~ar'l'l ~P4 ~ I AAOl.t.moreE~t7' AAO

AAO M"Oiny~/ Jf ~1i/;--- '"-'lAO, Buck..on oOr" ",AA03~1BlYTttCREEK 1t:! -'~ICKANJINNIE'- AAO lochi.ll AR015~ ~~!1 -'~ o'AAo'Bind"oo J:0 Y.rr~wono.l r

A~binbilla 2 t:! AAO Alice ~nI 1--- _ AAO lam~.mAAlJ. L.n;;~ Y ii.J!--- .JBOOJAAO Chinchinbill••l /$ AAfcoOlib~ ~~ InOI. l/$AAO TInoun1-- ~ _ - / AAO latomore S:.th 1 AAO w~~tt~~llA

AAO Bobodill. 1 (AAO Coolib.h lA'S-- AAO B~nOil AAO Appl.gro•• 1 ./ t. I I /1fSOUTHrr "'3 \ AA06P"~'" IlL r:-::-". ------ t,.AAO Trolford Park 1 2 3>-,A~Bonh...n 1 1 -'"'i,1 DUARRA '201;;;J, 1AAO RiCHMOND .... , / /

/ --"-13t:!"':~'/''4\g 2P: 'p'~-P 2 AAO Coonardoo 1/$ ...... ./ PIPELINE ( AAO B"O·II.1.<1A DIR~DA Cf I 1 1~ 21~ 1~6" ,,">

',/ 11.- AA05 \AAO 19 11 3D2 / \ r-"./ \~ AAO Bund.II.)AAO Oirind. South 1 PRINGlE Hop.Cre.k 17 1 P14 :.t.: 1 -..,1:-J r ...... ./

'-,9" D"S 6 '~ P 1Jt! ~6 .. 9 1~AOBa'dlomin9 (<::'<7"-../ I 4 V:J{f:' AAO Blyth,wood 1 AAO)\.'!!·i;l' .7 \ -, AAO \

......- ---\ AAO Bmonsfi.ld 11'\AAO MAFFRA BON~V.~ ~O .....-tWInn.8ltlOO~~;:f~5P BACK CREEK__ --.. ~ 1 "" P P ( CREEK AD Ifordlommg 3~ lo; )

,-'/ \ 5/i1 3 AAO Glenco. 1 1\ \ South 1 /"'.. '1~ 1 /," __

O~ \ 1 _ ,.-./ 6t:!,11 !!1( \ 4j? / P'AP W.llab.lla 1100 AAOHoIIyfood P1 /" ,/,'\.} ~ IPSTerrawong.1 /

__ - .... ~\ / '" 4;'t.-..AAO",- \ ,.-..... p' 1 \ '~o' AAO f."f"ld WestiP.er :l:f >;E;:.lTARRAWONGA '1>"-I I \ / AAO Coo".la 1 '!) .~O lyndon e....AAO fairfi.ld 1 P .0'5 I. !,,\" \../ AAO Anab"nchP~ 1 ~ 4 ~113

\ APO IC~1AP""""I '1 /' /6 ....AAOCombamool\ uncan rea p ""DOWn" AAO l ..do, 1t:! AP SNAKE CREEKp' ,~{ p' I\ \ f1 ):118 r /' I l /' 1 ,1 AAO Combarnoo Ealt 1

\ \ AP B.loowni. West 1 ~.J",,\1.9 ,...",,/ I / ./~ ) // )AP Sp,inob..k l.er \ r ..... ""'" r"" '3'!&tljA! TRINIDAD I

\ \ \ AP Inn~f8lg W..t 1.d / f1 \ V'l -' AAO T.unton b I 1~~-'}.P RO~kYb ..k1~' AP Inniseraio 1 l;11P y.l.bono C".k 1 p'AAO Boonda",l }

I o'~O Br_r.d• I• 1 /' r-' ,,-.J1!!'O B..~o.. lAP Ob"i..~ Jf {aAAO Bruced.l. la" 1 \ L /' n SUE Banoono South 1

I AP YibOno 1 v-~ AAO Sunnyb..k W.ltl p I 5 4

\\~ "" ..../ AAO SUNNYBANK3~ 11

a/A/591

~ Richmond-Bony Creek axisContours on seismic reffectorin U Evergreen Fm (ERM)

-500- Contour; interval 100 m

Contour; interval 50 m 10 15 'm

Fig. 28. Petroleum fields on Roma Shelf.

until well into the Early Cretaceous thatthe load on the Evergreen Formationapproached that needed to mobilize hydro~

carbons (cL Table 7). By then the migration

paths shown in Figure 27f were firmlyestablished. Hydrocarbons from the Ever­green Formation would have moved radialIy,mainly to the north and the east. Because of

51

149°15'149"00'

500

400

800-__...-'\

SUE Ni.II. North w..t 1p ;:f/ARO 7' I~ / I ",-./ /p

( -:-:-:: " \ t<' -,....... End GI.nora 1

o'AAO Mt B.agl. 1 AAO N"II. 1/$ ~ "" I j~

AAO NI.II. Ia J ": l\ //'\ \0'17 13 1~ 4 I

/'160', 1!l.. 10, /" 4", 16 1 / IAAO Tab.rs l:t AAO Ourb;;; 1 (I;l:~ 5 P 18 ..... ~.>' ' P End GI.na... 1;:.'A~ /-p4 AAO 1~8/$1~1B'" 4 ~~ 17.er AAOMtHop.-SOO //(

,,~ ....p'3 141, l' 1 11) \3~~ ~ 'of I ( /AAO'~I /$3 AAO~GRI\ 9~N~a/B'IO"1~Jb!~O ~O'd'I';U"1 \f;dJavoll /

WESTlANDS /$4 MOOGA ..:ifl At?1 \5p':~ GAlS" 5r dB \" J '" I/ i;l'RANG 6 PlEASA~T-!illlS \

AAO OUlb" I"" ( ~131 '" \ AAO SI..,y Cre.k I / --..~ I~AR011 3 Y ,_" " P7 13P: f~ I 1,,'P;':"'). J14 ~ /$AAO Wy... 1

/. 4p I~1, /$AAO HaVlnoton 1 ,,- ":1.4 /. AAO RASlIE I IAAO \A~03 pRBO 2 \ gl~ .... -LJ'!r:t 4:)" /

EUTHUllA'&, \gg228~ .1-", AV~lp'1 f 11d/O 1 '$ ,~!$ /AR013 \ (? RB04 .erRBO 3 AAO Wrn"on I ;:; 30 Ps ( AAO Sawpl! er.. 1

r _ AAO Mrnh 1.er \ AAO Mrnml lp' P'AAO Yan.l.h 1 \ p' ~Ro14 P.l.er / - 'v/ ....... ,/ / ",:--, --__ ~- / 1,0 ,,/SUE Wanoary North lp' /-' ~ T r""'l \ 0 Yonalah 1 -.-/ -..~ /,0 :\'Y ,/

I d AAO Inun ) \ Jf ~ AAO St8keyard 1 /......\ AAO W..oary 1 / It, _ AO y..~I.h 3 AAO Blythesdal.~rth)'<~ \..J t:! _/%'./

-'AO \ / AA06\ROM oTimburyHiII,2. ~AAO,Wa1t ..ooka J '"/AI HOdolon~ ,~_ .•dOSl1 AR08/ .r- P __./Jf AAO \ ' :to 4 ...AOli 'J ~- R?C4~R05 AAO Bore Vi.w 1 5 r£J1 ~

1~~ ROg.3.4 f> '" A -l.~~ (~iR04 r-- 4___ 9 DD/ lAOl4 'j:f- EA FOR :,iI'AJlOll AAO lat.more 1 :I'< '1 1/$-9

/ ,A Rom. South 1 --.. AAIl.Worooby South 1 -CJ:;' 1* 1R019. __ ...... - ~ar'l'l ~P4 ~ I AAOl.t.moreE~t7' AAO

AAO M"Oiny~/ Jf ~1i/;--- '"-'lAO, Buck..on oOr" ",AA03~1BlYTttCREEK 1t:! -'~ICKANJINNIE'- AAO lochi.ll AR015~ ~~!1 -'~ o'AAo'Bind"oo J:0 Y.rr~wono.l r

A~binbilla 2 t:! AAO Alice ~nI 1--- _ AAO lam~.mAAlJ. L.n;;~ Y ii.J!--- .JBOOJAAO Chinchinbill••l /$ AAfcoOlib~ ~~ InOI. l/$AAO TInoun1-- ~ _ - / AAO latomore S:.th 1 AAO w~~tt~~llA

AAO Bobodill. 1 (AAO Coolib.h lA'S-- AAO B~nOil AAO Appl.gro•• 1 ./ t. I I /1fSOUTHrr "'3 \ AA06P"~'" IlL r:-::-". ------ t,.AAO Trolford Park 1 2 3>-,A~Bonh...n 1 1 -'"'i,1 DUARRA '201;;;J, 1AAO RiCHMOND .... , / /

/ --"-13t:!"':~'/''4\g 2P: 'p'~-p 2 AAO Coonardoo 1/$ ...... ./ PIPELINE ( AAO B"O·II.1.<1A DIR~DA Cf I 1 1~ 21~ 1~6" ,,">

',/ 11.- AA05 \AAO 19 11 3D2 / \ r-"./ \~ AAO Bund.II.)AAO Oirind. South 1 PRINGlE Hop.Cre.k 17 1 P14 :.t.: 1 -..,1:-J r ...... ./

'-,9" D"S 6 '~ P 1Jt! ~6 .. 9 1~AOBa'dlomin9 (<::'<7"-../ I 4 V:J{f:' AAO Blyth,wood 1 AAO)\.'!!·i;l' .7 \ -, AAO \

......- ---\ AAO Bmonsfi.ld 11'\AAO MAFFRA BON~V.~ ~O .....-tWInn.8ltlOO~~;:f~5P BACK CREEK__ --.. ~ 1 "" P p ( CREEK AD Ifordlommg 3~ lo; )

,-'/ \ 5/i1 3 AAO Glenco. 1 1\ \ South 1 /"'.. '1~ 1 /," __

O~ \ 1 _ ,.-./ 6t:!,11 !!1( \ 4j? / P'AP W.llab.lla 1100 AAOHoIIyfood P1 /" ,/,'\.} ~ IPSTerrawong.1 /

__ - .... ~\ / '" 4;'t.-..AAO",- \ ,.-..... p' 1 \ '~o' AAO f."f"ld WestiP.er :l:f >;E;:.lTARRAWONGA '1>"-I I \ / AAO Coo".la 1 '!) .~O lyndon e....AAO fairfi.ld 1 P .0'5 I. !,,\" \../ AAO Anab"nchp~ 1 ~ 4 ~113

\ APO IC~1AP""""I '1 /' /6 ....AAOCombamool\ uncan rea p ""DOWn" AAO l ..do, 1t:! AP SNAKE CREEKp' ,~{ p' I\ \ f1 ):118 r /' I l /' 1 ,1 AAO Combarnoo Ealt 1

\ \ AP B.loowni. West 1 ~.J",,\1.9 ,...",,/ I / ./~ ) // )AP Sp,inob..k l.er \ r ..... ""'" r"" '3'!&tljA! TRINIDAD I

\ \ \ AP Inn~f8lg W..t 1.d / f1 \ V'l -' AAO T.unton b I 1~~-'}.P RO~kYb ..k1~' AP Inniseraio 1 l;11P y.l.bono C".k 1 p'AAO Boonda",l }

I o'~O Br_r.d• I• 1 /' r-' ,,-.J1!!'O B..~o.. lAP Ob"i..~ Jf {aAAO Bruced.l. la" 1 \ L /' n SUE Banoono South 1

I AP YibOno 1 v-~ AAO Sunnyb..k W.ltl p I 5 4

\\~ "" ..../ AAO SUNNYBANK3~ 11

a/A/591

~ Richmond-Bony Creek axisContours on seismic reffectorin U Evergreen Fm (ERM)

-500- Contour; interval 100 m

Contour; interval 50 m 10 15 'm

Fig. 28. Petroleum fields on Roma Shelf.

until well into the Early Cretaceous thatthe load on the Evergreen Formationapproached that needed to mobilize hydro~

carbons (cL Table 7). By then the migration

paths shown in Figure 27f were firmlyestablished. Hydrocarbons from the Ever­green Formation would have moved radialIy,mainly to the north and the east. Because of

52

the prevailing dip, they could have movedupward into the Hutton Sandstone, or later­ally into the Precipice Sandstone. Lateralmovements into still older units would havebeen possible where the structure was suit­able. By the end of the Early Cretaceous theadditional loading of generally more than500 m of sediment (Fig. 26) would haveensured widespread migration of hydrocar­bons out of the Evergreen Formation.

Thus in the Middle and Late Jurassic theonly hydrocarbons capable of migrating werethose from the Permian sequence. Thosewhich escaped from the Permo-Triassicsequence would have migrated to the south­west and southeast in the Early Jurassic,mainly in the Precipice Sandstone, but quiteprobably also in the Hutton Sandstone. Bythe Middle Jurassic some would haveentered stratigraphic and structural traps,but some would still be migrating. In theLate Jurassic, when the direction of migra­tion changed, some of the old traps becameineffectual, and new traps developed. In theEarly Cretaceous, hydrocarbons from theEvergreen Formation would have started tomigrate to the north and east, that is, in thesame direction as the older oil. From thenon, the same directions of migration pre­vailed, and hydrocarbons from either sourcecould have been moved vertically intoyounger units, or laterally through the unitthey were in, or into older units. The load­ing of sedimentary cover rocks reached amaximum in the late Early Cretaceous, andthereafter declined as erosion predominated.In the mid-Tertiary increases in dip mayhave led to further migration.

ROMA SHELF ACCUMULATIONS

Several papers have been published bygeologists of Mines Administration Pty Ltdon various aspects of the Roma Shelf depo­sits; among the more important are a reviewof petroleum in the Roma-Springsure area(Traves, 1966), a case history of fields andreservoirs by Swindon (1968), a discussionof stratigraphic traps by Traves (1971), andan environmental study of hydrocarbon-pro­ducing Lower Jurassic sandstones by Sellet al. (1972). A brief description of theJurassic reservoirs was given by Hogetoorn

( 1968), and outlines of the Bony Creek gasfield by Power (1966), of the Pickanjinniegas field by Gray (1969), and of the PineRidge and Raslie gas fields by Hogetoorn(1970).

On the Roma Shelf there are a number ofrelatively small fields producing gas or oil,or both, from a variety of reservoirs (Tables5, 6; Fig. 28). By far the most importantproduct is gas, which is piped to Brisbane.Most of the gas produced is from the LowerJurassic Precipice Sandstone, but it has alsobeen recovered from the Permian BackCreek and Blackwater Groups, the MiddleTriassic Showgrounds Sandstone andMoolayember Formation, and the LowerJurassic Evergreen Formation. The twolargest fields are Bony Creek and PleasantHills, in which the initial recoverablereserves were around 800 and 950 millionm:l respectively.

Commercial oil has been found only inthe Precipice Sandstone, with the Trinidadfield the largest (initial recoverable reserves17 000 m:l), and it has been trucked to theMoonie oil pipeline. Other significant oil­bearing horizons include the Upper PermianBandanna Formation, the Middle TriassicShowgrounds Sandstone and MoolayemberFormation, and the Lower Jurassic Ever­green Formation.

Traps are generalIy stratigraphic, al­though structure is an important subsidiaryfactor in many fields. The following discus­sion of traps is drawn from Traves (1971)and Sell et al. (1972). The WallumbillaSouth field produces at a depth of about1750 m from a thin sand in the PermianMuggleton Formation, which may be abeach sand, and whose permeability is ashigh as 36 millidarcys. The ShowgroundsSandstone is an important producer in anumber of fields. It is a sand deposited onthe eastern part of the Roma Shelf by aseries of southeasterly-flowing streams, andhas porosity as high as 19 percent and per­meability as high as 4 darcys. In most placesthe trapping mechanism is an up-dip pinch­out of the sand, which is seldom more than10 m thick.

Twenty-four gas fields have been discov-

J

52

the prevailing dip, they could have movedupward into the Hutton Sandstone, or later­ally into the Precipice Sandstone. Lateralmovements into still older units would havebeen possible where the structure was suit­able. By the end of the Early Cretaceous theadditional loading of generally more than500 m of sediment (Fig. 26) would haveensured widespread migration of hydrocar­bons out of the Evergreen Formation.

Thus in the Middle and Late Jurassic theonly hydrocarbons capable of migrating werethose from the Permian sequence. Thosewhich escaped from the Permo-Triassicsequence would have migrated to the south­west and southeast in the Early Jurassic,mainly in the Precipice Sandstone, but quiteprobably also in the Hutton Sandstone. Bythe Middle Jurassic some would haveentered stratigraphic and structural traps,but some would still be migrating. In theLate Jurassic, when the direction of migra­tion changed, some of the old traps becameineffectual, and new traps developed. In theEarly Cretaceous, hydrocarbons from theEvergreen Formation would have started tomigrate to the north and east, that is, in thesame direction as the older oil. From thenon, the same directions of migration pre­vailed, and hydrocarbons from either sourcecould have been moved vertically intoyounger units, or laterally through the unitthey were in, or into older units. The load­ing of sedimentary cover rocks reached amaximum in the late Early Cretaceous, andthereafter declined as erosion predominated.In the mid-Tertiary increases in dip mayhave led to further migration.

ROMA SHELF ACCUMULATIONS

Several papers have been published bygeologists of Mines Administration Pty Ltdon various aspects of the Roma Shelf depo­sits; among the more important are a reviewof petroleum in the Roma-Springsure area(Traves, 1966), a case history of fields andreservoirs by Swindon (1968), a discussionof stratigraphic traps by Traves (1971), andan environmental study of hydrocarbon-pro­ducing Lower Jurassic sandstones by Sellet al. (1972). A brief description of theJurassic reservoirs was given by Hogetoorn

( 1968), and outlines of the Bony Creek gasfield by Power (1966), of the Pickanjinniegas field by Gray (1969), and of the PineRidge and Raslie gas fields by Hogetoorn(1970).

On the Roma Shelf there are a number ofrelatively small fields producing gas or oil,or both, from a variety of reservoirs (Tables5, 6; Fig. 28). By far the most importantproduct is gas, which is piped to Brisbane.Most of the gas produced is from the LowerJurassic Precipice Sandstone, but it has alsobeen recovered from the Permian BackCreek and Blackwater Groups, the MiddleTriassic Showgrounds Sandstone andMoolayember Formation, and the LowerJurassic Evergreen Formation. The twolargest fields are Bony Creek and PleasantHills, in which the initial recoverablereserves were around 800 and 950 millionm:l respectively.

Commercial oil has been found only inthe Precipice Sandstone, with the Trinidadfield the largest (initial recoverable reserves17 000 m:l), and it has been trucked to theMoonie oil pipeline. Other significant oil­bearing horizons include the Upper PermianBandanna Formation, the Middle TriassicShowgrounds Sandstone and MoolayemberFormation, and the Lower Jurassic Ever­green Formation.

Traps are generalIy stratigraphic, al­though structure is an important subsidiaryfactor in many fields. The following discus­sion of traps is drawn from Traves (1971)and Sell et al. (1972). The WallumbillaSouth field produces at a depth of about1750 m from a thin sand in the PermianMuggleton Formation, which may be abeach sand, and whose permeability is ashigh as 36 millidarcys. The ShowgroundsSandstone is an important producer in anumber of fields. It is a sand deposited onthe eastern part of the Roma Shelf by aseries of southeasterly-flowing streams, andhas porosity as high as 19 percent and per­meability as high as 4 darcys. In most placesthe trapping mechanism is an up-dip pinch­out of the sand, which is seldom more than10 m thick.

Twenty-four gas fields have been discov-

J

53

Producing well

P Dry hole

? Dry hole, show ofoi/and gas

Contour; interval 20 mDatum Sea Level

Q/A/592

Fig. 29. Structure map of Moonie Oil Field.

ered in the Precipice Sandstone at depthsranging from 850 to 1350 m. The formationwas deposited by streams flowing generallynorth-northeast. Sinuous bodies of poroussand, with an average porosity of 20 per­cent, and generally less than 5 km wide and

10 m thick, appear to have been originallydeposited in shallow valleys where the ini­tially clayey sands were extensively reworkedby streams. Permeability in the channelsands is as high as 2 darcys, and most ofthe petroleum accumulations occur where

53

Producing well

P Dry hole

? Dry hole, show ofoi/and gas

Contour; interval 20 mDatum Sea Level

Q/A/592

Fig. 29. Structure map of Moonie Oil Field.

ered in the Precipice Sandstone at depthsranging from 850 to 1350 m. The formationwas deposited by streams flowing generallynorth-northeast. Sinuous bodies of poroussand, with an average porosity of 20 per­cent, and generally less than 5 km wide and

10 m thick, appear to have been originallydeposited in shallow valleys where the ini­tially clayey sands were extensively reworkedby streams. Permeability in the channelsands is as high as 2 darcys, and most ofthe petroleum accumulations occur where

54

MoonieFault

Fig. 30. Cross-section through Moonie Oil Field.

Irnl1200

1300

1400

these northeasterly-trending belts of channelsands cross positive axes trending north­west. Some traps may consist of up-dip per­meability barriers within belts of channelsands.

Several gas accumulations in the lowerpart of the Evergreen Formation are believedto be in shoreline sands enclosed in imper­meable sandstone and shale. They normallyoccur on the flanks of basement ridges.

The general pattern of migration in thebasin (see pp. 47-52) suggests that thehydrocarbons in the Jurassic sequence mayhave been derived from Permian sources inthe Early and Middle Jurassic, when migra­tion was to the west, or later, when migra­tion was to the north. Hydrocarbons fromthe Evergreen Formation can only havemoved in Early Cretaceous or later times,when migration was to the north. The trap­ping mechanism in the Precipice Sandstonewould have worked equally well from theEarly Jurassic to the Holocene, although thenorthwesterly-trending positive axes wouldhave been subhorizontal in Early and MiddleJurassic times (their present southeasterlyplunge was developed later).

There are great difficulties in predictingthe occurrence of such stratigraphic traps,as the seismic tool does not have sufficientresolving power to differentiate porous sand­stone belts from non-porous belts. By 1973most of the more easily identifiable targetson structural highs had been drilled, and thesearch was concentrated on the Permian

sequence.Moonie Oil Field

The Union-Kern-AOG Moonie No. 1 wellflowed oil at 220 m 3 a day through a I-inchchoke in December 1961, but it was notuntil September 1962 that the Moonie fieldwas declared commercial. This, the firstcommercial oil field in Australia, stimulatedwidespread exploration in the Surat Basin.Production reached a peak of 1600 m3 perday in 1966 and had declined to less than240 m3 per day by 1974. The oil is water­driven, and water began to invade the peri­pheral wells in 1966. Thirty-four wells havebeen drilled, of which all but five were pro­ducers.

Union Oil Co. geologists have publishedpapers on various aspects of the field, mostof which have been summarized by Buckleyet al. (1969), from whom most of the fol­lowing discussion is drawn. The history ofexploration in the Surat Basin and the geo­logy of the Moonie field were outlined byMoran & Gussow (1963). There followed adiscussion of production facilities andmethods by Pyle & Buckley (1965) and ofsubsurface and reservoir conditions in thefield by Pyle (1967).

The field is an anticline on a horst blockand is about 7 km long by 2 km wide (Figs29, 30); its initial recoverable reserves wereestimated at 3 000 000 m3 which had beendepleted by 93 percent late in 1973. Themain producing horizon is the basal sand­stone member of the Lower Jurassic Preci-

54

MoonieFault

Fig. 30. Cross-section through Moonie Oil Field.

Irnl1200

1300

1400

these northeasterly-trending belts of channelsands cross positive axes trending north­west. Some traps may consist of up-dip per­meability barriers within belts of channelsands.

Several gas accumulations in the lowerpart of the Evergreen Formation are believedto be in shoreline sands enclosed in imper­meable sandstone and shale. They normallyoccur on the flanks of basement ridges.

The general pattern of migration in thebasin (see pp. 47-52) suggests that thehydrocarbons in the Jurassic sequence mayhave been derived from Permian sources inthe Early and Middle Jurassic, when migra­tion was to the west, or later, when migra­tion was to the north. Hydrocarbons fromthe Evergreen Formation can only havemoved in Early Cretaceous or later times,when migration was to the north. The trap­ping mechanism in the Precipice Sandstonewould have worked equally well from theEarly Jurassic to the Holocene, although thenorthwesterly-trending positive axes wouldhave been subhorizontal in Early and MiddleJurassic times (their present southeasterlyplunge was developed later).

There are great difficulties in predictingthe occurrence of such stratigraphic traps,as the seismic tool does not have sufficientresolving power to differentiate porous sand­stone belts from non-porous belts. By 1973most of the more easily identifiable targetson structural highs had been drilled, and thesearch was concentrated on the Permian

sequence.Moonie Oil Field

The Union-Kern-AOG Moonie No. 1 wellflowed oil at 220 m 3 a day through a I-inchchoke in December 1961, but it was notuntil September 1962 that the Moonie fieldwas declared commercial. This, the firstcommercial oil field in Australia, stimulatedwidespread exploration in the Surat Basin.Production reached a peak of 1600 m3 perday in 1966 and had declined to less than240 m3 per day by 1974. The oil is water­driven, and water began to invade the peri­pheral wells in 1966. Thirty-four wells havebeen drilled, of which all but five were pro­ducers.

Union Oil Co. geologists have publishedpapers on various aspects of the field, mostof which have been summarized by Buckleyet al. (1969), from whom most of the fol­lowing discussion is drawn. The history ofexploration in the Surat Basin and the geo­logy of the Moonie field were outlined byMoran & Gussow (1963). There followed adiscussion of production facilities andmethods by Pyle & Buckley (1965) and ofsubsurface and reservoir conditions in thefield by Pyle (1967).

The field is an anticline on a horst blockand is about 7 km long by 2 km wide (Figs29, 30); its initial recoverable reserves wereestimated at 3 000 000 m3 which had beendepleted by 93 percent late in 1973. Themain producing horizon is the basal sand­stone member of the Lower Jurassic Preci-

pice Sandstone, the '58-0 sand', which is 20to 60 m thick and about 1800 m below sur­face. The productive limits of this reservoirare controlled by an oil/water interface. Anupper sandstone member, the '56-4 sand', isseparated from the main sand by 30 m oftight sand and silt and, although always pre­sent, is productive only in certain wells. Itsproductive limits are controlled by perme­ability barriers and an oil/water interface.

The '58-0 sand' is generally quartzose andconsists of a number of lenticular sandbodies. The grainsize ranges from very fineto conglomeratic, but most of the sand ismedium to very coarse-grained. Carbona­ceous laminae and high-angled cross-bed­ding are common. The lower part of thesand body is generally less clayey andslightly coarser than the upper part. Theaverage horizontal permeability is about 300millidarcys, but the effective vertical perme­ability is zero in anyone core because of thenumerous tight streaks. Average porosity is18 percent, and the initial water saturationwas 47 percent. The reservoir fluid is con­siderably undersaturated with gas, and thereare differences in the solution gas: oil ratioacross the main producing horizon. Thehighest gas: oil ratio was 56: 1, correspond­ing to a bubble point pressure of 1680 psig,and the average is 45: 1.

Geologically this area is fairly typical ofthe Chinchilla-Goondiwindi Slope. By LateTriassic time the area, which lies on an up­thrown block immediately east of theMoonie Fault on the eastern hinge-line ofthe basin, had been eroded to give a rangeof hills of the 'Kuttung Formation' flankedwest of the fault by a low plain of Triassicsediments, and to the east by a plain of Per­mian sediments and tuffs. There was a gen­eral tilt to the north and, in the Early Juras­sic, the '58-0 sand' was spread across theold surface by northerly and northeasterlyflowing braided streams to form an extensivealluvial plain. The sand overlying the Per­mian sequence is more clayey and less per­meable than that overlying the 'Kuttung For­mation', and it appears that the coarsersediment was deposited on the slopes andthe finer on the plains.

55

The history of entrapment of the oil hasbeen outlined by Buckley et al. (1969).Between the deposition of the PrecipiceSandstone and the close of Walloon CoalMeasures (Middle Jurassic) time, oil enteredthe Precipice Sandstone, migrated to thesouthwest up the regional slope, and wastrapped south of the present Moonie field bypermeability barriers and areas of no sanddeposition corresponding to basement highs.Soon after (Middle or Late Jurassic) theregional tilt was reversed. The plunge on theMoonie structure, which is a drape over abasement ridge, was also reversed and oilmigrated northwestward until it reached thepresent closure, which was then at the lowerend of a southwesterly-plunging regionalnose. Movement on the faults bounding theanticline to the northwest and southeast in­creased the relief during the tilting episode.There was sufficient northeasterly closure totrap the oil migrating back up the nose.

If this reconstruction is correct, the oil atMoonie must have originated in the Permiansequence, as oil in the Evergreen Formationwould not have been expelled until the load­ing upon it became adequate in the EarlyCretaceous (see also pp. 45-52). ThatPermian oil was present in the vicinity issuggested by the nearby UKA Cabawin No.1 accumulation in Permian sediments. Thealternative that the oil migrated from theEvergreen Formation as suggested by Moran& Gussow (1963) remains viable, but theaccumulation would have occurred laterthan is generally suggested. The mid-Ter­tiary epeirogenic movements increased theregional tilt, and may have caused renewedmovement on the old fault lines, and perhapsrenewed migration.

Alton Oil FieldThe Alton field, which lies near the

eastern edge of the St George/Bollon Slope(Fig. 6), was described by Buckley et al.( 1969), and the following discussion ismainly based on this paper.

The Union-Kern-AOG Alton No. 1 wellwas drilled in 1964 on a seismically deter­mined structure on the basin side of the StGeorge/Bollon Slope, to test closure ofEvergreen Formation/Precipice Sandstone

pice Sandstone, the '58-0 sand', which is 20to 60 m thick and about 1800 m below sur­face. The productive limits of this reservoirare controlled by an oil/water interface. Anupper sandstone member, the '56-4 sand', isseparated from the main sand by 30 m oftight sand and silt and, although always pre­sent, is productive only in certain wells. Itsproductive limits are controlled by perme­ability barriers and an oil/water interface.

The '58-0 sand' is generally quartzose andconsists of a number of lenticular sandbodies. The grainsize ranges from very fineto conglomeratic, but most of the sand ismedium to very coarse-grained. Carbona­ceous laminae and high-angled cross-bed­ding are common. The lower part of thesand body is generally less clayey andslightly coarser than the upper part. Theaverage horizontal permeability is about 300millidarcys, but the effective vertical perme­ability is zero in anyone core because of thenumerous tight streaks. Average porosity is18 percent, and the initial water saturationwas 47 percent. The reservoir fluid is con­siderably undersaturated with gas, and thereare differences in the solution gas: oil ratioacross the main producing horizon. Thehighest gas: oil ratio was 56: 1, correspond­ing to a bubble point pressure of 1680 psig,and the average is 45: 1.

Geologically this area is fairly typical ofthe Chinchilla-Goondiwindi Slope. By LateTriassic time the area, which lies on an up­thrown block immediately east of theMoonie Fault on the eastern hinge-line ofthe basin, had been eroded to give a rangeof hills of the 'Kuttung Formation' flankedwest of the fault by a low plain of Triassicsediments, and to the east by a plain of Per­mian sediments and tuffs. There was a gen­eral tilt to the north and, in the Early Juras­sic, the '58-0 sand' was spread across theold surface by northerly and northeasterlyflowing braided streams to form an extensivealluvial plain. The sand overlying the Per­mian sequence is more clayey and less per­meable than that overlying the 'Kuttung For­mation', and it appears that the coarsersediment was deposited on the slopes andthe finer on the plains.

55

The history of entrapment of the oil hasbeen outlined by Buckley et al. (1969).Between the deposition of the PrecipiceSandstone and the close of Walloon CoalMeasures (Middle Jurassic) time, oil enteredthe Precipice Sandstone, migrated to thesouthwest up the regional slope, and wastrapped south of the present Moonie field bypermeability barriers and areas of no sanddeposition corresponding to basement highs.Soon after (Middle or Late Jurassic) theregional tilt was reversed. The plunge on theMoonie structure, which is a drape over abasement ridge, was also reversed and oilmigrated northwestward until it reached thepresent closure, which was then at the lowerend of a southwesterly-plunging regionalnose. Movement on the faults bounding theanticline to the northwest and southeast in­creased the relief during the tilting episode.There was sufficient northeasterly closure totrap the oil migrating back up the nose.

If this reconstruction is correct, the oil atMoonie must have originated in the Permiansequence, as oil in the Evergreen Formationwould not have been expelled until the load­ing upon it became adequate in the EarlyCretaceous (see also pp. 45-52). ThatPermian oil was present in the vicinity issuggested by the nearby UKA Cabawin No.1 accumulation in Permian sediments. Thealternative that the oil migrated from theEvergreen Formation as suggested by Moran& Gussow (1963) remains viable, but theaccumulation would have occurred laterthan is generally suggested. The mid-Ter­tiary epeirogenic movements increased theregional tilt, and may have caused renewedmovement on the old fault lines, and perhapsrenewed migration.

Alton Oil FieldThe Alton field, which lies near the

eastern edge of the St George/Bollon Slope(Fig. 6), was described by Buckley et al.( 1969), and the following discussion ismainly based on this paper.

The Union-Kern-AOG Alton No. 1 wellwas drilled in 1964 on a seismically deter­mined structure on the basin side of the StGeorge/Bollon Slope, to test closure ofEvergreen Formation/Precipice Sandstone

56

(a)1500 m

~ ~r- 1600m

r--:PreCifJ'

'Ce 1700 mS8,

f<" 1800mdOs"Wandoan;~ s"1,-

I'.!.)"/!" t- f:", 1901lm\'y\_\'~~ --s"'~/:'':;.')-_ -"'" ~el11'\ _ - ~ __

... -I (, ....l/\... ~-l/I..... (\Y... l.... /.\...:: I :M 1000.,\~\,-I " .... ,....... ' .... h,A '-...'Basement "J\-' 1--~L\ I ....T;Y~~~ ....,,~~,/ ........ t":'"'- ..../.'J\..\I '- ,-, ",J -! _\;\~- ~I:::l-

3km'--_-'-__'--_~I

(b)

117

THICKNESS 'B' SAND

• Well number- Isopach lines of total permeable sand (m)

• UKA Alton 1

1585 ..

6

-~-'-----.16'1,," /", 4

"''''_5

STRUCTURE MAPTOP EVERGREEN FORMATION

Fig. 31. Stucture of Alton Oil Field.

p7

THICKNESS '0' SAND

8 Well numberIsopach lines of rotal permeable sand (m)

O/A/594

sands known to occur in the area. It pro­duced 180 m3 a day through a i-inch bot­tom hole choke from the interval 6060 to6120 feet (1847-1865 m). Six more pro­ducing wells were drilled, and by January1966 oil was being trucked to the Mooniepipeline. Production never exceeded 160 m3

a day, and by 1968 all the wells had to bepumped, with production around 110 m3 aday; by late 1973 production had declinedto around 44 m3 a day. The producing hori­zons are about 1850 m below ground leveL

Alton oil is of 54 0 API gravity, and hasan average solution gas: oil ratio of 73: 1,and bubble point pressure of 917 psig.Average reservoir porosity is 17 percent andpermeability is 240 millidarcys. Initial watersaturation was 45 percent. Although littlewater was produced until 1969, Buckley etai, have suggested that the producingmechanism was ay partial water drive andfluid expulsion.

In the Alton field the traps are partlystratigraphic and partly structural (see Fig.31 b). The field is situated on a small anti­cline, and measures about 2,5 km by 1 km.Production is obtained from five separatesands designated A, B, C, D, and E withina sequence of shale, siltstone, and sandstone,80 m thick, called the 'Evergreen-Precipiceunit' by the Company. The sequence is pro­bably equivalent to the Lower Jurassic Ever­green Formation, and directly overlies theTriassic Wandoan Formation which rests ona Permian sequence (Fig. 31). The wellswere completed in different sands, but the A,C, and E sands are of very limited extentand most of the oil is contained in the BandD sands, neither of which exceeds 4 m inthickness (Fig, 31).

The Alton sands appear to be sinuouschannel-like bodies that cross the easternside of the structure, They represent onlybrief surges of current restricted to narrow

56

(a)1500 m

~ ~r- 1600m

r--:PreCifJ'

'Ce 1700 mS8,

f<" 1800mdOs"Wandoan;~ s"1,-

I'.!.)"/!" t- f:", 1901lm\'y\_\'~~ --s"'~/:'':;.')-_ -"'" ~el11'\ _ - ~ __

... -I (, ....l/\... ~-l/I..... (\Y... l.... /.\...:: I :M 1000.,\~\,-I " .... ,....... ' .... h,A '-...'Basement "J\.' 1--~L\ I ....T;Y~~~ ....,,~~,/ ........ t":'"'- ..../.'J\..\I '- ,-, ",J -! _\;\~- ~I:::l-

3km'--_-'-__'--_~I

(b)

117

THICKNESS 'B' SAND

• Well number- Isopach lines of total permeable sand (m)

• UKA Alton 1

1585 ..

6

-~-'-----.16'1,," /", 4

"''''_5

STRUCTURE MAPTOP EVERGREEN FORMATION

Fig. 31. Stucture of Alton Oil Field.

p7

THICKNESS '0' SAND

8 Well numberIsopach lines of rotal permeable sand (m)

O/A/594

sands known to occur in the area. It pro­duced 180 m3 a day through a i-inch bot­tom hole choke from the interval 6060 to6120 feet (1847-1865 m). Six more pro­ducing wells were drilled, and by January1966 oil was being trucked to the Mooniepipeline. Production never exceeded 160 m3

a day, and by 1968 all the wells had to bepumped, with production around 110 m3 aday; by late 1973 production had declinedto around 44 m3 a day. The producing hori­zons are about 1850 m below ground leveL

Alton oil is of 54 0 API gravity, and hasan average solution gas: oil ratio of 73: 1,and bubble point pressure of 917 psig.Average reservoir porosity is 17 percent andpermeability is 240 millidarcys. Initial watersaturation was 45 percent. Although littlewater was produced until 1969, Buckley etai, have suggested that the producingmechanism was ay partial water drive andfluid expulsion.

In the Alton field the traps are partlystratigraphic and partly structural (see Fig.31 b). The field is situated on a small anti­cline, and measures about 2,5 km by 1 km.Production is obtained from five separatesands designated A, B, C, D, and E withina sequence of shale, siltstone, and sandstone,80 m thick, called the 'Evergreen-Precipiceunit' by the Company. The sequence is pro­bably equivalent to the Lower Jurassic Ever­green Formation, and directly overlies theTriassic Wandoan Formation which rests ona Permian sequence (Fig. 31). The wellswere completed in different sands, but the A,C, and E sands are of very limited extentand most of the oil is contained in the BandD sands, neither of which exceeds 4 m inthickness (Fig, 31).

The Alton sands appear to be sinuouschannel-like bodies that cross the easternside of the structure, They represent onlybrief surges of current restricted to narrow

channels. Probably because relief was lowerand runotI was less, blanket sands like thoseof the Moonie area did not develop. TheAlton sandstones are thicker to the southand east, where no suitable structural trapsexist.

The available oil in each sand is limitedby zero permeability lines, and an indivi­dual oil/water interface for each sand. An­other factor is the thickness of sand, whichis greatest near the centres of the channels.

The Alton structure is a drape over afaulted basement block. Oil entering thesands probably originated in the surroundingEvergreen Formation; it was expelled duringthe Early Cretaceous (see pp. 47-52),migrated up-dip, and was trapped within thechannels on the anticline.

The Bollon areaOne area which has been little explored,

but which Exon (1974) has pointed outpossibly has some economic potential, is anarea around Bollon in the southwestern partof the basin. His maps were based on seis­mic maps compiled by United GeophysicalCorp. (1963), and on well data and wire­line-logged water-bores; most of them arereproduced here at a larger scale.

Basement in this area (Fig. 7) lies muchhigher than it does below the Mimosa Syn­cline, and parts of it were exposed through­out the whole of the Permo-Triassic. Juras­sic sediments gradually lapped up onto theelevated basement blocks, and the LowerJurassic stream sands of the Hutton Sand­stone were deposited directly on basementover a wide area (Fig. 18). The WalloonCoal Measures are believed to overlap theHutton Sandstone to the west, sealing itagainst the basement rise.

In the Early and Middle Jurassic (Fig.27) the migration paths for most of anyhydrocarbons from the Permian sequence inthe Taroom Trough that had made their wayinto the J urassic sequence led directly intothis area. Such hydrocarbons would gener­ally have migrated up-dip in the PrecipiceSandstone until it pinched out against base­ment. They would then either have beentrapped or have made their way via the basalsands of the Evergreen Formation up the

57

basement surface and into the Hutton Sand­stone. Onee in the Hutton Sandstone, assum­ing it to have been already sealed by theWalloon Coal Measures, they would havemade their way up-dip towards the thinnersediments shown by the isopach map of theHutton Sandstone and Walloon Coal Mea-

. sures (Fig. 2 I). West of Dirranbandi thiswould have been to the west, and south ofDirranbandi to the south, that is, out of theDirranbandi Syncline. To the west anyhydrocarbons would have been stopped bythe Walloon Coal Measures seal against base­ment in the Bollon area, but to the souththey would have migrated out of the areaconsidered, unless trapped by permeabilityor structural barriers within the HuttonSandstone.

In Late Jurassie and later times (Fig.270, when the regional dip changed in theBollon area, the direction of migration wasto the north, although it remained unchangedsouth of Dirranbandi. Hydrocarbons for­merly trapped against basement would havetended to migrate northward, and somehydrocarbons in other traps could also havebeen freed.

The reconnaissance seismic surveys byUnited Geophysical Corp. ( 1963) usedsimple techniques and very widely spacedtraverses. The complex structure outlined onthe basement surface suggested that thestructures in the overlying Hutton Sandstonewould also be complex. Thus it is possiblethat some of the hydrocarbons that migratedinto the area in the Early and Middle Juras­sic were permanently trapped and could notmigrate out of the area when the directionof migration changed to the north. Perme­ability traps elongated across the directionof migration probably developed in the flu­vial sands that had been laid down byeasterly-flowing streams on an irregular sur­face at the edge of the basin.

No wells have been drilled in the HuttonSandstone in this area, which would appearto merit further examination. Although someof the faulting in the area is probably Caino­zoic (Senior, 1970), by analogy with the restof the basin it is likely that much of thebasement relief is original (as is also sug-

channels. Probably because relief was lowerand runotI was less, blanket sands like thoseof the Moonie area did not develop. TheAlton sandstones are thicker to the southand east, where no suitable structural trapsexist.

The available oil in each sand is limitedby zero permeability lines, and an indivi­dual oil/water interface for each sand. An­other factor is the thickness of sand, whichis greatest near the centres of the channels.

The Alton structure is a drape over afaulted basement block. Oil entering thesands probably originated in the surroundingEvergreen Formation; it was expelled duringthe Early Cretaceous (see pp. 47-52),migrated up-dip, and was trapped within thechannels on the anticline.

The Bollon areaOne area which has been little explored,

but which Exon (1974) has pointed outpossibly has some economic potential, is anarea around Bollon in the southwestern partof the basin. His maps were based on seis­mic maps compiled by United GeophysicalCorp. (1963), and on well data and wire­line-logged water-bores; most of them arereproduced here at a larger scale.

Basement in this area (Fig. 7) lies muchhigher than it does below the Mimosa Syn­cline, and parts of it were exposed through­out the whole of the Permo-Triassic. Juras­sic sediments gradually lapped up onto theelevated basement blocks, and the LowerJurassic stream sands of the Hutton Sand­stone were deposited directly on basementover a wide area (Fig. 18). The WalloonCoal Measures are believed to overlap theHutton Sandstone to the west, sealing itagainst the basement rise.

In the Early and Middle Jurassic (Fig.27) the migration paths for most of anyhydrocarbons from the Permian sequence inthe Taroom Trough that had made their wayinto the J urassic sequence led directly intothis area. Such hydrocarbons would gener­ally have migrated up-dip in the PrecipiceSandstone until it pinched out against base­ment. They would then either have beentrapped or have made their way via the basalsands of the Evergreen Formation up the

57

basement surface and into the Hutton Sand­stone. Onee in the Hutton Sandstone, assum­ing it to have been already sealed by theWalloon Coal Measures, they would havemade their way up-dip towards the thinnersediments shown by the isopach map of theHutton Sandstone and Walloon Coal Mea-

. sures (Fig. 2 I). West of Dirranbandi thiswould have been to the west, and south ofDirranbandi to the south, that is, out of theDirranbandi Syncline. To the west anyhydrocarbons would have been stopped bythe Walloon Coal Measures seal against base­ment in the Bollon area, but to the souththey would have migrated out of the areaconsidered, unless trapped by permeabilityor structural barriers within the HuttonSandstone.

In Late Jurassie and later times (Fig.270, when the regional dip changed in theBollon area, the direction of migration wasto the north, although it remained unchangedsouth of Dirranbandi. Hydrocarbons for­merly trapped against basement would havetended to migrate northward, and somehydrocarbons in other traps could also havebeen freed.

The reconnaissance seismic surveys byUnited Geophysical Corp. ( 1963) usedsimple techniques and very widely spacedtraverses. The complex structure outlined onthe basement surface suggested that thestructures in the overlying Hutton Sandstonewould also be complex. Thus it is possiblethat some of the hydrocarbons that migratedinto the area in the Early and Middle Juras­sic were permanently trapped and could notmigrate out of the area when the directionof migration changed to the north. Perme­ability traps elongated across the directionof migration probably developed in the flu­vial sands that had been laid down byeasterly-flowing streams on an irregular sur­face at the edge of the basin.

No wells have been drilled in the HuttonSandstone in this area, which would appearto merit further examination. Although someof the faulting in the area is probably Caino­zoic (Senior, 1970), by analogy with the restof the basin it is likely that much of thebasement relief is original (as is also sug-

58

TABLE 8. GAS SHOWS IN PERMIAN SEQUENCE SOUTH OF LATITUDE 24°30'S(To late 1973)

Traps Potential andShows Percentage Producing Percentage

Area Unit Drilled Shows Fields Fields

West Blackwater Group 64 8 12 2 4Back Creek Group 44 14 27 4 9Reids Dome Beds 15 4 27 0 0

East Blackwater Group 16 2 12 0 0Back Creek Group 31 4 13 0 0

Total 96 23 24 6 6

TABLE 9. OIL SHOWS IN PERMIAN SEQUENCE SOUTH OF LATITUDE 24°30'S(To late 1973)

Traps Percentage PotentialArea Unit Drilled Shows Shows Fields

West Blackwater Group 64 2 3 0Back Creek Group 44 3 7 0Reids Dome Beds 15 2 13 0

East Blackwater Group 16 1 6 0Back Creek Group 31 0 0 0

Total 96 7 7 0

gested by the isopachs of the Hutton Sand­stone and Walloon Coal Measures), and thatfurther movement on basement faults wasassociated with Middle and Late Jurassicepeirogenic movement.

In conclusion, it is probable that hydro­carbons migrated into this area in the Earlyand Middle Jurassic and were trapped. Thelater regional tilt to the north probablyspilled many of these concentrations, but thearea is complex and suitable stratigraphicand structural traps are probably present. Am6re intensive modern seismic survey mightdelineate targets which could be tested bydrilling to depths of 1000 to 1500 m.

ConclusionsThere is no doubt that substantial quan­

tities of gas, and perhaps oil, will continueto be found in the Surat Basin. Major newfinds are most likely to be found in the twosequences generally recognized as being themost prospective-the Permian beds and thebasal part of the Jurassic Precipice Sand­stone. Another unexplored possibility is theLower Jurassic Hutton Sandstone in thesouthwestern part of the basin.

The Permian sequence remains prospect­ive although, until the end of 1973, the

results of drilling were rather disappointing,with some gas but no oil production (Tables5, 6, 8, 9). There is no doubt that hydro­carbons were generated within the sequence,and any porous and pearmeable sand bodieswould be possible reservoirs. To date thePermian sequence has been remarkablytight. The most prospective area around themargin of the Roma Shelf is up-dip of thelikely source beds in the Taroom Trough,and has been throughout the history of thebasin. Beach sands in the marine Permiansequence, sealed up-dip by fine-grainedswamp sediments or pinching out againstbasement, are the most probable potentialreservoirs (see Traves, 1971). Hydrocar­bons have been recorded in a number ofwells, but good reservoirs have yet to befound, despite the use of high-resolutionsebmic methods and considerable drilling inthe Wallumbilla area.

Tables 8 and 9 show that gas has beenrecorded in the Permian sequence in some25 percent of the wells which penetrated it,but oil in only 7 percent. They suggest thatthe Back Creek Group is the most prospec­tive part of the Permian sequence, and thatthe western side of the basin is more pros­pective than the eastern side.

58

TABLE 8. GAS SHOWS IN PERMIAN SEQUENCE SOUTH OF LATITUDE 24°30'S(To late 1973)

Traps Potential andShows Percentage Producing Percentage

Area Unit Drilled Shows Fields Fields

West Blackwater Group 64 8 12 2 4Back Creek Group 44 14 27 4 9Reids Dome Beds 15 4 27 0 0

East Blackwater Group 16 2 12 0 0Back Creek Group 31 4 13 0 0

Total 96 23 24 6 6

TABLE 9. OIL SHOWS IN PERMIAN SEQUENCE SOUTH OF LATITUDE 24°30'S(To late 1973)

Traps Percentage PotentialArea Unit Drilled Shows Shows Fields

West Blackwater Group 64 2 3 0Back Creek Group 44 3 7 0Reids Dome Beds 15 2 13 0

East Blackwater Group 16 1 6 0Back Creek Group 31 0 0 0

Total 96 7 7 0

gested by the isopachs of the Hutton Sand­stone and Walloon Coal Measures), and thatfurther movement on basement faults wasassociated with Middle and Late Jurassicepeirogenic movement.

In conclusion, it is probable that hydro­carbons migrated into this area in the Earlyand Middle Jurassic and were trapped. Thelater regional tilt to the north probablyspilled many of these concentrations, but thearea is complex and suitable stratigraphicand structural traps are probably present. Am6re intensive modern seismic survey mightdelineate targets which could be tested bydrilling to depths of 1000 to 1500 m.

ConclusionsThere is no doubt that substantial quan­

tities of gas, and perhaps oil, will continueto be found in the Surat Basin. Major newfinds are most likely to be found in the twosequences generally recognized as being themost prospective-the Permian beds and thebasal part of the Jurassic Precipice Sand­stone. Another unexplored possibility is theLower Jurassic Hutton Sandstone in thesouthwestern part of the basin.

The Permian sequence remains prospect­ive although, until the end of 1973, the

results of drilling were rather disappointing,with some gas but no oil production (Tables5, 6, 8, 9). There is no doubt that hydro­carbons were generated within the sequence,and any porous and pearmeable sand bodieswould be possible reservoirs. To date thePermian sequence has been remarkablytight. The most prospective area around themargin of the Roma Shelf is up-dip of thelikely source beds in the Taroom Trough,and has been throughout the history of thebasin. Beach sands in the marine Permiansequence, sealed up-dip by fine-grainedswamp sediments or pinching out againstbasement, are the most probable potentialreservoirs (see Traves, 1971). Hydrocar­bons have been recorded in a number ofwells, but good reservoirs have yet to befound, despite the use of high-resolutionsebmic methods and considerable drilling inthe Wallumbilla area.

Tables 8 and 9 show that gas has beenrecorded in the Permian sequence in some25 percent of the wells which penetrated it,but oil in only 7 percent. They suggest thatthe Back Creek Group is the most prospec­tive part of the Permian sequence, and thatthe western side of the basin is more pros­pective than the eastern side.

The Precipice Sandstone has been the tar­get for most of the drilling in the basin andhas produced both gas and oil. Where itforms a thick porous blanket sand the con­tained hydrocarbons have generally migratedlaterally up-dip to escape at outcrop, or havebeen flushed out by water moving throughthis excellent aquifer. Only where suchblanket sands are folded into a large anti­cline, as at Moonie, or where fault-traps areinvolved, is there much chance that hydro­carbons have escaped flushing. The mostobvious structural traps have been drilled,and the eastern and southern parts of thebasin must now be regarded as unprospec­tive.

On the Roma Shelf, on the other hand,the widespread gas finds in the PrecipiceSandstone have generally involved lateralporosity-permeability barriers within a rela­tively thin sandstone sequence. Sinuousbodies of permeable sand, which are inter­preted as old channel-sand complexes, arelimited laterally by impermeable sands. Mostof the gas fields have been found where anti­clines complete the trapping mechanism, andmost of these anticlinal traps have beendrilled.

Assuming that belts of permeable sandare surrounded by impermeable beds, it ispossible that purely stratigraphic traps mayexist well down the flanks of the anticlines,or in the synclines. Refined seismic tech­niques may help to define such targets, anda second phase of petroleum search on theRoma Shelf seems inevitable.

On the southwestern side of the basinfurther traps of the Alton type almost cer­tainly exist-isolated thin sandstone reser­voirs that represent stream channels withinthe impermeable Lower Jurassic EvergreenFormation. Small fields of this type mayexist in any structural setting, but their pre­diction is difficult.

In the Bollon area, and indeed elsewerein the southwestern part of the basin, theLower Jurassic Hutton Sandstone is virtuallyuntested. Some of the sands in pinch-outsagainst basement highs, and permeablechannel sands in impermeable sedimentsnear the basement source areas may still

59

contain some hydrocarbons, in spite of thefact that artesian water has probably flushedout any hydrocarbons from most of the Hut­ton Sandstone.

To summarize, the best prospects are thePrecipice Sandstone on the Roma Shelf andthe marine Permian sequence where it abutson the Roma Shelf; the Hutton Sandstone inthe southwest is less promising. Furthersmall gas fields may be found in the Preci­pice Sandstone at a depth of about 1500 m.The Permian sandstones are thicker thanthose of the Precipice Sandstone, and if theywere permeable they could yield muchgreater supplies of petroleum. Most of thewells would be less than 2000 m deep.Exploration of the Hutton Sandstone in theBollon area would require good-quality seis­mic work to define targets, most of whichwould be less than 1000 m deep.

ECONOMIC GEOLOGY(Excluding Petroleum)

GroundwaterThe Surat Basin contains several pressure

aquifers which flow to the surface in thedeeper parts of the basin; water is drawnfrom numerous bores for stock and domesticuse. Most of the aquifers lie in the Precipice,Hutton, Pilliga, Gubberamunda, and HooraySandstones, but less important aquifers occurwithin the Injune Creek Group, the BungilFormation, and the Rolling Downs Group.The rates of flow have diminished over theyears and many of the artesian bores haveceased to flow. Flows of over 4000 m 3 perday, which were once commonplace, arenow rare.

The shallowest major aquifers in differentareas are plotted in Figure 32; the oldest arenearest the margin of the basin, and showclearly the effect of the basinward dip. Thedepth to economic supplies of water seldomexceeds 300 m, except in the central part ofthe basin (see Fig. 32). In the central partof the basin, where abundant supplies ofgood water could be obtained at consider­able depth from the Hooray Sandstone,water is pumped from the overlying RollingDowns Group because it is so muchshallower, although supplies are small andsaline. Within the Rolling Downs Group the

The Precipice Sandstone has been the tar­get for most of the drilling in the basin andhas produced both gas and oil. Where itforms a thick porous blanket sand the con­tained hydrocarbons have generally migratedlaterally up-dip to escape at outcrop, or havebeen flushed out by water moving throughthis excellent aquifer. Only where suchblanket sands are folded into a large anti­cline, as at Moonie, or where fault-traps areinvolved, is there much chance that hydro­carbons have escaped flushing. The mostobvious structural traps have been drilled,and the eastern and southern parts of thebasin must now be regarded as unprospec­tive.

On the Roma Shelf, on the other hand,the widespread gas finds in the PrecipiceSandstone have generally involved lateralporosity-permeability barriers within a rela­tively thin sandstone sequence. Sinuousbodies of permeable sand, which are inter­preted as old channel-sand complexes, arelimited laterally by impermeable sands. Mostof the gas fields have been found where anti­clines complete the trapping mechanism, andmost of these anticlinal traps have beendrilled.

Assuming that belts of permeable sandare surrounded by impermeable beds, it ispossible that purely stratigraphic traps mayexist well down the flanks of the anticlines,or in the synclines. Refined seismic tech­niques may help to define such targets, anda second phase of petroleum search on theRoma Shelf seems inevitable.

On the southwestern side of the basinfurther traps of the Alton type almost cer­tainly exist-isolated thin sandstone reser­voirs that represent stream channels withinthe impermeable Lower Jurassic EvergreenFormation. Small fields of this type mayexist in any structural setting, but their pre­diction is difficult.

In the Bollon area, and indeed elsewerein the southwestern part of the basin, theLower Jurassic Hutton Sandstone is virtuallyuntested. Some of the sands in pinch-outsagainst basement highs, and permeablechannel sands in impermeable sedimentsnear the basement source areas may still

59

contain some hydrocarbons, in spite of thefact that artesian water has probably flushedout any hydrocarbons from most of the Hut­ton Sandstone.

To summarize, the best prospects are thePrecipice Sandstone on the Roma Shelf andthe marine Permian sequence where it abutson the Roma Shelf; the Hutton Sandstone inthe southwest is less promising. Furthersmall gas fields may be found in the Preci­pice Sandstone at a depth of about 1500 m.The Permian sandstones are thicker thanthose of the Precipice Sandstone, and if theywere permeable they could yield muchgreater supplies of petroleum. Most of thewells would be less than 2000 m deep.Exploration of the Hutton Sandstone in theBollon area would require good-quality seis­mic work to define targets, most of whichwould be less than 1000 m deep.

ECONOMIC GEOLOGY(Excluding Petroleum)

GroundwaterThe Surat Basin contains several pressure

aquifers which flow to the surface in thedeeper parts of the basin; water is drawnfrom numerous bores for stock and domesticuse. Most of the aquifers lie in the Precipice,Hutton, Pilliga, Gubberamunda, and HooraySandstones, but less important aquifers occurwithin the Injune Creek Group, the BungilFormation, and the Rolling Downs Group.The rates of flow have diminished over theyears and many of the artesian bores haveceased to flow. Flows of over 4000 m 3 perday, which were once commonplace, arenow rare.

The shallowest major aquifers in differentareas are plotted in Figure 32; the oldest arenearest the margin of the basin, and showclearly the effect of the basinward dip. Thedepth to economic supplies of water seldomexceeds 300 m, except in the central part ofthe basin (see Fig. 32). In the central partof the basin, where abundant supplies ofgood water could be obtained at consider­able depth from the Hooray Sandstone,water is pumped from the overlying RollingDowns Group because it is so muchshallower, although supplies are small andsaline. Within the Rolling Downs Group the

60

148°

50 100 km'- ...l' --',

Mundubbera

26°

Hooray Sst-Mooga Sst

Gubberamunda Sst-Pilliga Sst

Adori Sst

Hutton Sst

Marburg Sst

Precipice Sst

-300- Depth below ground level ofHooray Sst-Mooga Sst aquifers (m)

L..l.-1 Edge of Surat Basin

----l- General limit of flowing bores

Fig. 32. Distribution of aquifers.

60

148°

50 100 km'- ...l' --',

Mundubbera

26°

Hooray Sst-Mooga Sst

Gubberamunda Sst-Pilliga Sst

Adori Sst

Hutton Sst

Marburg Sst

Precipice Sst

-300- Depth below ground level ofHooray Sst-Mooga Sst aquifers (m)

L..l.-1 Edge of Surat Basin

----l- General limit of flowing bores

Fig. 32. Distribution of aquifers.

61

TABLE 10. CHEMISTRY OF MAJOR AQUIFERS

Number 01West 01 149 0 E East of 149 0 E

Total l1C03 /Cl Number 01 Total l1C03 /ClAquifer Bores Dissolved Ratio Bores Dissolved RatioSampled Solids (ppm) (equivalents) Sampled Solids (ppm) (equivalents)

Hooray 19 600-1650 0.05-5.3Sandstone (av. 1100) (av.2.5)

Mooga 600-1570 1.4-4.9 23 1350-2200 0.8-17.6Sandstone (av. 1100) (av.2) (av.1800) (av.4)Gubberamunda 650-900 1.4-3.5 17 850-2100 0.6-11Sandstone (av. 8(0) (av.2) (av. 1300) (av. 3)Pilliga 11 750-1750 2.7-4.4Sandstone (av.900) (av.3.5)

major aquifers are the Coreena Memberand the lower part of the Griman Creek For­mation.

In all the aquifers most of the water isstored in the pore spaces between sandgrains in sandstone. Fracture porosity isgenerally unimportant. There are rechargeareas around the northern and eastern mar­gins of the basin, and the water moves in ageneral southerly direction (Ogilvie, 1954).Recharge probably takes place from belts ofalluvium and sandy soil overlying the aqui­fers, and also through joints in the sandstoneoutcrops.

The main aquifers generally contain bicar­bonate water that is suitable for stock andin places for domestic use. According to theGroundwater Map of Australia (1972) themain aquifers west of an arc throughTaroom, Roma, Surat, Talwood, andGoondiwindi contain an average of less than1000 ppm total dissolved solids, whereas inmost of the area to the east of the arc thevalues are between 1000 and 3000 ppm;values of less than 1000 ppm are alsorecorded in the Goondiwindi-Inglewood­Millmerran area around the Texas High.The salinity of the Precipice Sandstonevaries in a complex manner from less than1000 to over 4000 ppm (see, e.g., Cony­beare,1970).

Table 10 shows the results of analyses ofwater from major aquifers carried out by theGovernment Chemical Laboratories, Bris­bane, for the BMR (see Appendix 5). Thequality of the water is generally better onthe western side of the basin than in the east,with total dissolved solids averaging 1000ppm as against 1500 ppm. However, thePilIiga Sandstone in the east averages only

900 ppm total dissolved solids. The pre­dominance of bicarbonate over chloride (themajor ions present) is quite marked.

The aquifers in the Rolling Downs Groupcontain chloride water, some of which issuitable for stock, but little for human use.The salinity is nearly always greater than1000 ppm, and exceeds 3000 ppm in thearea to the west and south of Sural. The In­june Creek Group also contains highly salinechloride water in the Injune-Taroom area,with salinities ranging from 1000 to over3000 ppm.

Many of the Cainozoic sands and sand­stones contain subartesian water that rangesfrom fresh to saline, but the only suppliesof importance are those obtained from thealluvium along the Condamine River systemand in the area of the Dirranbandi Syncline.Lumsden (1966) has reported that thequality of the water in the alluvium alongthe Condamine River ranged from poor toexcellent, and that supplies are adequate forsmall irrigation schemes near the river.

Surface waterAlthough the major rivers and streams

flow only intermittently they contain per­manent and semi-permanent waterholes. Inthe north and east, where there is some reliefand where the annual rainfall is over 500mm, large earth tanks and dams can be con­structed on the clayey soils in and nearcreeks, gullies, and depressions. They aregenerally only used for watering stock, buta few of the larger dams have been used forirrigation of small areas.

CoalThe coals in the Walloon Coal Measures

have been mined near Injune and Warra for

61

TABLE 10. CHEMISTRY OF MAJOR AQUIFERS

Number 01West 01 149 0 E East of 149 0 E

Total l1C03 /Cl Number 01 Total l1C03 /ClAquifer Bores Dissolved Ratio Bores Dissolved RatioSampled Solids (ppm) (equivalents) Sampled Solids (ppm) (equivalents)

Hooray 19 600-1650 0.05-5.3Sandstone (av. 1100) (av.2.5)

Mooga 600-1570 1.4-4.9 23 1350-2200 0.8-17.6Sandstone (av. 1100) (av.2) (av.1800) (av.4)Gubberamunda 650-900 1.4-3.5 17 850-2100 0.6-11Sandstone (av. 8(0) (av.2) (av. 1300) (av. 3)Pilliga 11 750-1750 2.7-4.4Sandstone (av.900) (av.3.5)

major aquifers are the Coreena Memberand the lower part of the Griman Creek For­mation.

In all the aquifers most of the water isstored in the pore spaces between sandgrains in sandstone. Fracture porosity isgenerally unimportant. There are rechargeareas around the northern and eastern mar­gins of the basin, and the water moves in ageneral southerly direction (Ogilvie, 1954).Recharge probably takes place from belts ofalluvium and sandy soil overlying the aqui­fers, and also through joints in the sandstoneoutcrops.

The main aquifers generally contain bicar­bonate water that is suitable for stock andin places for domestic use. According to theGroundwater Map of Australia (1972) themain aquifers west of an arc throughTaroom, Roma, Surat, Talwood, andGoondiwindi contain an average of less than1000 ppm total dissolved solids, whereas inmost of the area to the east of the arc thevalues are between 1000 and 3000 ppm;values of less than 1000 ppm are alsorecorded in the Goondiwindi-Inglewood­Millmerran area around the Texas High.The salinity of the Precipice Sandstonevaries in a complex manner from less than1000 to over 4000 ppm (see, e.g., Cony­beare,1970).

Table 10 shows the results of analyses ofwater from major aquifers carried out by theGovernment Chemical Laboratories, Bris­bane, for the BMR (see Appendix 5). Thequality of the water is generally better onthe western side of the basin than in the east,with total dissolved solids averaging 1000ppm as against 1500 ppm. However, thePilIiga Sandstone in the east averages only

900 ppm total dissolved solids. The pre­dominance of bicarbonate over chloride (themajor ions present) is quite marked.

The aquifers in the Rolling Downs Groupcontain chloride water, some of which issuitable for stock, but little for human use.The salinity is nearly always greater than1000 ppm, and exceeds 3000 ppm in thearea to the west and south of Sural. The In­june Creek Group also contains highly salinechloride water in the Injune-Taroom area,with salinities ranging from 1000 to over3000 ppm.

Many of the Cainozoic sands and sand­stones contain subartesian water that rangesfrom fresh to saline, but the only suppliesof importance are those obtained from thealluvium along the Condamine River systemand in the area of the Dirranbandi Syncline.Lumsden (1966) has reported that thequality of the water in the alluvium alongthe Condamine River ranged from poor toexcellent, and that supplies are adequate forsmall irrigation schemes near the river.

Surface waterAlthough the major rivers and streams

flow only intermittently they contain per­manent and semi-permanent waterholes. Inthe north and east, where there is some reliefand where the annual rainfall is over 500mm, large earth tanks and dams can be con­structed on the clayey soils in and nearcreeks, gullies, and depressions. They aregenerally only used for watering stock, buta few of the larger dams have been used forirrigation of small areas.

CoalThe coals in the Walloon Coal Measures

have been mined near Injune and Warra for

62

use on the railways,but after the conversionto diesel locomotives in the 1960s the mineswere closed. The coals are suitable for usein powerhouses, and for the production ofpetrochemicals and synthetic gas.

At the Maranoa Colliery near Injune (seeMollan et aI., 1972, pp. 89-90) 540000tonnes of coal were produced between 1933and 1963. The main seam was up to 1.4 mthick and consisted of high-volatile weaklycoking bituminous coal. W. Hawthorne*gave the following data for the main seam:fixed carbon, 42.6 to 51.1 percent; calorificvalue, 7528 to 8133 kcal per kg; and ashcontent, 13.1 to 22.3 percent.

Several holes drilled by the QueenslandDepartment of Mines in the Injune CreekGroup intersected coal in the Walloon CoalMeasures between the Eurombah Anticlineand Taroom (Swarbrick, 1973). Seams ofperhydrous coal up to 3.6 m thick wereintersected at various levels. The coal isblack, has a greasy lustre, a conchoidal orsubconchoidal fracture, and a poorlydeveloped cleat. A typical proximate analysis(air-dried basis) is as follows: inherentmoisture, 4.0 percent; volatile matter, 38.8percent; fixed carbon, 35.2 percent; andash, 22.0 percent. The calorific valueranged from 5500 to 6700 kcal per kg, andthe sulphur content from 0.3 to 0.8 percent.Analyses of other coals from the WalloonCoal Measures show that high volumetricyields of fairly high calorific value gas, hightar yields, and low coke yields can beobtained.

Recently drilling has been carried out byprivate companies in the Millmerran, Wan­doan, and Chinchilla areas to locate coal foron-field power stations. Lone Star Explora­tion NL in a press statement on 8 May 1973announced that the Chinchilla area 'appearsto have ... two potential open cut areas withinferred reserves in excess of 100 millionlong tons of raw coal'. In the same statementthe company announced that its Wandoanprospect has at least two areas of interest,one with inferred reserves of about 15 mil­lion tons of raw coal, and the other with in­ferred reserves of about 97 million tons.

Following the decline in production of theIpswich fields because of damage caused bythe 1974 floods, the management of theSwanbank powerhouse was considering theuse of coal from the Millmerran area, whereMillmerran Coal Pty Ltd has evaluated opencut and underground prospects, the best ofwhich (Commodore prospect) has provenreserves of 126 million tonnes, of which 90million tonnes could be open-cut (The Aus­tralian Financial Review, 14 Feb. 1974).

The Permian coal measures are outsidethe scope of this Bulletin (see Dickins &Malone, 1973, for general discussion). Thethin coal seams in the Springbok Sandstoneand Norwood Mudstone Member of theWestbourne Formation (Swarbrick, 1973),and in the Orallo Formation and RollingDowns Group, are not of economic signifi­cance.

BentoniteBentonite is widespread in the Orallo

Formation (Duff & Milligan, 1967; Exon &Duff, 1968) between Roma and Miles, andthin beds have also been reported in theInjune Creek Group (e.g. Swarbrick, 1973).

Duff & Milligan (1967) have reported thediscovery of bentonite and bentonitic clay inbeds up to I m thick in the Orallo Forma­tion north of Yuleba. The surface and drillsamples analysed show that the bentonitedoes not meet the API specifications for usein drilling muds, but that it could possiblybe used, after alkaline treatment, for iron orepelletizing.

A similar deposit (Figs 33, 34) wasreported by Exon & Duff (1968) north ofMiles, where beds up to 1.5 m thick cropout, and thinner beds of bentonite wereintersected in shallow drill holes. Analyseshave shown that this bentonite is sodiummontmorillonite and has potential as a basefor drilling mud, and possibly for iron orepelletizing.

No attempt has been made by BMR toevaluate these deposits fully, but it is en­couraging to note that the beds dip at a lowangle, and that they could probably beworked by open-cut. The Miles deposit lies

* Geological Survey of Queensland file note-Maranoa mine area, Injune, 16/7/56.

62

use on the railways,but after the conversionto diesel locomotives in the 1960s the mineswere closed. The coals are suitable for usein powerhouses, and for the production ofpetrochemicals and synthetic gas.

At the Maranoa Colliery near Injune (seeMollan et aI., 1972, pp. 89-90) 540000tonnes of coal were produced between 1933and 1963. The main seam was up to 1.4 mthick and consisted of high-volatile weaklycoking bituminous coal. W. Hawthorne*gave the following data for the main seam:fixed carbon, 42.6 to 51.1 percent; calorificvalue, 7528 to 8133 kcal per kg; and ashcontent, 13.1 to 22.3 percent.

Several holes drilled by the QueenslandDepartment of Mines in the Injune CreekGroup intersected coal in the Walloon CoalMeasures between the Eurombah Anticlineand Taroom (Swarbrick, 1973). Seams ofperhydrous coal up to 3.6 m thick wereintersected at various levels. The coal isblack, has a greasy lustre, a conchoidal orsubconchoidal fracture, and a poorlydeveloped cleat. A typical proximate analysis(air-dried basis) is as follows: inherentmoisture, 4.0 percent; volatile matter, 38.8percent; fixed carbon, 35.2 percent; andash, 22.0 percent. The calorific valueranged from 5500 to 6700 kcal per kg, andthe sulphur content from 0.3 to 0.8 percent.Analyses of other coals from the WalloonCoal Measures show that high volumetricyields of fairly high calorific value gas, hightar yields, and low coke yields can beobtained.

Recently drilling has been carried out byprivate companies in the Millmerran, Wan­doan, and Chinchilla areas to locate coal foron-field power stations. Lone Star Explora­tion NL in a press statement on 8 May 1973announced that the Chinchilla area 'appearsto have ... two potential open cut areas withinferred reserves in excess of 100 millionlong tons of raw coal'. In the same statementthe company announced that its Wandoanprospect has at least two areas of interest,one with inferred reserves of about 15 mil­lion tons of raw coal, and the other with in­ferred reserves of about 97 million tons.

Following the decline in production of theIpswich fields because of damage caused bythe 1974 floods, the management of theSwanbank powerhouse was considering theuse of coal from the Millmerran area, whereMillmerran Coal Pty Ltd has evaluated opencut and underground prospects, the best ofwhich (Commodore prospect) has provenreserves of 126 million tonnes, of which 90million tonnes could be open-cut (The Aus­tralian Financial Review, 14 Feb. 1974).

The Permian coal measures are outsidethe scope of this Bulletin (see Dickins &Malone, 1973, for general discussion). Thethin coal seams in the Springbok Sandstoneand Norwood Mudstone Member of theWestbourne Formation (Swarbrick, 1973),and in the Orallo Formation and RollingDowns Group, are not of economic signifi­cance.

BentoniteBentonite is widespread in the Orallo

Formation (Duff & Milligan, 1967; Exon &Duff, 1968) between Roma and Miles, andthin beds have also been reported in theInjune Creek Group (e.g. Swarbrick, 1973).

Duff & Milligan (1967) have reported thediscovery of bentonite and bentonitic clay inbeds up to I m thick in the Orallo Forma­tion north of Yuleba. The surface and drillsamples analysed show that the bentonitedoes not meet the API specifications for usein drilling muds, but that it could possiblybe used, after alkaline treatment, for iron orepelletizing.

A similar deposit (Figs 33, 34) wasreported by Exon & Duff (1968) north ofMiles, where beds up to 1.5 m thick cropout, and thinner beds of bentonite wereintersected in shallow drill holes. Analyseshave shown that this bentonite is sodiummontmorillonite and has potential as a basefor drilling mud, and possibly for iron orepelletizing.

No attempt has been made by BMR toevaluate these deposits fully, but it is en­couraging to note that the beds dip at a lowangle, and that they could probably beworked by open-cut. The Miles deposit lies

* Geological Survey of Queensland file note-Maranoa mine area, Injune, 16/7/56.

63

Fig. 33. Thick bed of bentonite overlying coal in the lowermost part of the Orallo Formation. Five bedscrop out in a scarp immediately north of BMR Chinchilla Nos. 1 & 2 on the Miles-Wandoan road,

3 km north-northwest of Miles.

on the Miles-Wandoan railway, and IS lessthan 350 km west of Brisbane.

Iron oreBeds of oolitic limonite are present in the

Westgrove Ironstone Member and an un­named oolite member of the Evergreen For­mation (Mollan et al., 1972, p. 91). Alimonite bed up to 3 m thick crops out in theoolite member in the Cockatoo Creek areaeast of Taroom, where ore reserves havebeen estimated at 140 million tonnes. Thethickness of the ore averages lA m, theoverburden 1.8 m, and the average grade is37.5 percent iron (Urquhart, 1962). Fur­ther deposits are present under thicker over­burden, both in the Dawsonvale/CockatooCreek area and in the Pontypool-Geddes­vale-Kilbeggan area.

The Westgrove Ironstone Member is gen­erally thinner than the oolite member andcontains less ironstone, but up to 3 m ofoolitic ironstone is present in places in theEddystone Sheet area (Mollan et al., 1972).

Road metal and aggregateThe Tertiary basalts in the northern and

eastern parts of the basin are quarried forroad metal and aggregate. In the south andwest, however, the only road metal andaggregate available are Cainozoic gravels,and toughened beds in the deep-weatheringprofile that are only marginally suitable.

The major basalt quarries near Amby andnorth of Roma and Dalby supply most ofthe needs in the north. Other quarries couldbe developed in any of the extensive basaltsas the need arises. At the Amby quarry

63

Fig. 33. Thick bed of bentonite overlying coal in the lowermost part of the Orallo Formation. Five bedscrop out in a scarp immediately north of BMR Chinchilla Nos. 1 & 2 on the Miles-Wandoan road,

3 km north-northwest of Miles.

on the Miles-Wandoan railway, and IS lessthan 350 km west of Brisbane.

Iron oreBeds of oolitic limonite are present in the

Westgrove Ironstone Member and an un­named oolite member of the Evergreen For­mation (Mollan et al., 1972, p. 91). Alimonite bed up to 3 m thick crops out in theoolite member in the Cockatoo Creek areaeast of Taroom, where ore reserves havebeen estimated at 140 million tonnes. Thethickness of the ore averages lA m, theoverburden 1.8 m, and the average grade is37.5 percent iron (Urquhart, 1962). Fur­ther deposits are present under thicker over­burden, both in the Dawsonvale/CockatooCreek area and in the Pontypool-Geddes­vale-Kilbeggan area.

The Westgrove Ironstone Member is gen­erally thinner than the oolite member andcontains less ironstone, but up to 3 m ofoolitic ironstone is present in places in theEddystone Sheet area (Mollan et al., 1972).

Road metal and aggregateThe Tertiary basalts in the northern and

eastern parts of the basin are quarried forroad metal and aggregate. In the south andwest, however, the only road metal andaggregate available are Cainozoic gravels,and toughened beds in the deep-weatheringprofile that are only marginally suitable.

The major basalt quarries near Amby andnorth of Roma and Dalby supply most ofthe needs in the north. Other quarries couldbe developed in any of the extensive basaltsas the need arises. At the Amby quarry

64

Fig. 34. Close-up photograph of bentonite in Figure 33. The bentonite has been formed by the altera­tion of volcanic ash, which contains numerous glass shards.

54000 m" of aggregate had been producedup to 1962 (Shipway, 1962), and goodreserves exist to the north and south of thequarry. The intrusive basalt 30 km northof Roma has also been quarried for someyears. Other quarries farther east includeKings Pit north of Bell, the Malakoff Quarryeast of limbour, and several used and dis­used quarries north and east of Dalby. Thebasalts southwest of Millmerran and southof Goondiwindi have been used locally forroad metal.

In the lightly populated areas of the southand west few of the roads are surfaced.Local deposits of Cainozoic gravel and sandand ferruginous layers in the deep-weather­ing profile are used for surfacing parts of the

more important roads, and Cainozoic gravelis used for bitumen aggregate in the StGeorge area.

ClayA brickworks at Chinchilla uses clay from

deeply weathered lurassic sediments.Hueber & Holland (1952) * have reportedthat the clays are suitable for bricks, agri­cultural pipes, and pottery. Analyses ofmudstones in the Doncaster Member nearRoma (Allen, 1961) have shown that theyare suitable for brickmaking. A 10-m bedof kaolinitic claystone in the Hooray Sand­stone is exposed 32 km south of Mungallalaon the Mount Elliott Homestead road(Exon et al., 1967), and other clay pros­pects are discussed by Mollan et al. (1972).

* CSIRO report on clays in the Chinchilla area filed at the Geological Survey of Queensland, Brisbane.

64

Fig. 34. Close-up photograph of bentonite in Figure 33. The bentonite has been formed by the altera­tion of volcanic ash, which contains numerous glass shards.

54000 m" of aggregate had been producedup to 1962 (Shipway, 1962), and goodreserves exist to the north and south of thequarry. The intrusive basalt 30 km northof Roma has also been quarried for someyears. Other quarries farther east includeKings Pit north of Bell, the Malakoff Quarryeast of limbour, and several used and dis­used quarries north and east of Dalby. Thebasalts southwest of Millmerran and southof Goondiwindi have been used locally forroad metal.

In the lightly populated areas of the southand west few of the roads are surfaced.Local deposits of Cainozoic gravel and sandand ferruginous layers in the deep-weather­ing profile are used for surfacing parts of the

more important roads, and Cainozoic gravelis used for bitumen aggregate in the StGeorge area.

ClayA brickworks at Chinchilla uses clay from

deeply weathered lurassic sediments.Hueber & Holland (1952) * have reportedthat the clays are suitable for bricks, agri­cultural pipes, and pottery. Analyses ofmudstones in the Doncaster Member nearRoma (Allen, 1961) have shown that theyare suitable for brickmaking. A 10-m bedof kaolinitic claystone in the Hooray Sand­stone is exposed 32 km south of Mungallalaon the Mount Elliott Homestead road(Exon et al., 1967), and other clay pros­pects are discussed by Mollan et al. (1972).

* CSIRO report on clays in the Chinchilla area filed at the Geological Survey of Queensland, Brisbane.

Miscellaneous mineralsOpal was mined on Mamaree and Beech­

wood stations, some 60 km southeast ofSurat, in the early years of the century. Allthe shafts are in the Griman Creek Forma­tion, in which the opal is concentrated nearthe base of the deep-weathering profile. Noofficial records are available, and it isdoubtful whether much commercial opal wasfound.

Oil shale and kerosene shale have beenreported from the Walloon Coal Measures inthe Injune area, and distillation tests have

65

yielded as much as 225 I of crude oil pertonne. The kerosene shale from the OralloFormation near OralIo (Jensen, 1926)yielded 200 I of crude oil per tonne.

Various mineral deposits occur in theolder rocks surrounding the Surat Basin. TheCracow Goldfield is discussed by Mollan etal. ( 1972), old copper and tin workingsnortheast of Chinchilla by Exon et al.(1968), and the tin, gold, copper, silver,lead, arsenic, manganese, molybdenite, lime­stone and gemstone occurrences of theTexas High by Olgers & Flood (1974).

Miscellaneous mineralsOpal was mined on Mamaree and Beech­

wood stations, some 60 km southeast ofSurat, in the early years of the century. Allthe shafts are in the Griman Creek Forma­tion, in which the opal is concentrated nearthe base of the deep-weathering profile. Noofficial records are available, and it isdoubtful whether much commercial opal wasfound.

Oil shale and kerosene shale have beenreported from the Walloon Coal Measures inthe Injune area, and distillation tests have

65

yielded as much as 225 I of crude oil pertonne. The kerosene shale from the OralloFormation near OralIo (Jensen, 1926)yielded 200 I of crude oil per tonne.

Various mineral deposits occur in theolder rocks surrounding the Surat Basin. TheCracow Goldfield is discussed by Mollan etal. ( 1972), old copper and tin workingsnortheast of Chinchilla by Exon et al.(1968), and the tin, gold, copper, silver,lead, arsenic, manganese, molybdenite, lime­stone and gemstone occurrences of theTexas High by Olgers & Flood (1974).

66

ROCK UNITS OLDER THAN THE SURAT BASIN

BASEMENT TO THE BOWEN BASIN

Basement in the area consists of induratedand deformed sediments, low-grade meta­sediments, acid igneous complexes, and vol­canics, whose distribution and present reliefare shown in Plate 9. In the deep parts ofthe Taroom Trough basement has not beenreached by exploratory wells. The sedi­ments, metasediments, and volcanics rangein age from Devonian to Early Permian, andare intruded by granites ranging from pos­sibly as old as Devonian to Early Triassic;the granites generally become younger tothe east, in harmony with the eastwardmigration of the Tasman Geosyncline. Themain basement rock units are summarized inTables 11 and 12.

Timbury Hills Formation (pzt)

The term 'Timbury Hills Formation' iscommonly used for all the indurated sedi­ments and metasediments that form thebasement to the west of the Mimosa Syn­cline. Late Devonian plants have beenrecovered from two wells, but as thesequence probably includes rock units of dif­ferent ages the validity of the name isdoubtful. The oldest sediments overlying thebasement are the Lower Permian ReidsDome Beds, which rest unconformably onthe Timbury Hills Formation in theArbroath Trough.

'Kuttung Formation' and equivalents (C-Pk)

All the volcanics and sediments of Car­boniferous to Early Permian age are hereincluded in the 'Kuttung Formation' ofMack (1963), despite the doubtful validityof the name. The age and relations ofthe rocks recovered in cores are uncertain,and it is not possible to identify separateunits such as the Camboon Andesite andCombarngo Volcanics.

The outcrop equivalents of the 'KuttungFormation' include the Camboon Andesiteto the west of the Auburn Complex, theYarrol Basin sequence east of the AuburnComplex, and the Texas Beds (Clt) in theTexas High.

Roma granites (Clg)'Roma granites' is the term used by

Houston (1964) for the granites penetratedby exploratory wells on the Roma Shelf.She maintained that they were probably partof the same intrusive body that underlies theother basement rocks ~n the shelf. TheRoma granites consist mainly of adamellite;they intrude the Timbury Hills Formation,which is hornfelsed in some wells (Houston,1964). The K-Ar ages obtained on samplesfrom five AAa wells range from 298 to 350m.y. (A. W. Webb, table 1 in Houston,1964 ). All the samples are weathered, so theaccuracy of the determinations is doubtful.The presence of arkosic sediments above thegranites indicates a period of subaerial ero­sion.

Auburn Complex (Cug & P-TRg)The Auburn Complex (see Mollan et al.,

1972) consists of granodiorite and minordiorite cut by dykes of dacite and andesite.The complex intrudes Palaeozoic metamor­phics and the Lower Permian CamboonAndesite; the isotopic ages obtained onsamples from the complex range from earlyLate Carboniferous to early Late Permian(311-240 m.y.). The results suggest thatthe complex consists of a western Carboni­ferous body (Cug) and an eastern UpperPermian to Triassic body (P-TRg) (Webb &McDougall, 1968) which were mapped byWhitaker, Murphy, & Rollason (1974). Thecomplex is unconformably overlain byLower Jurassic sediments.

Yarraman Complex (pzm & P-TRg)The Yarraman Complex (see Exon et al.,

1968) consists of foliated acid rocks (pzm)in the south, and massive granodiorite(P-TRg) in the north.

The grade of metamorphism of thefoliated acid rocks (pzm) increases to thenorth. The schists and phyllites in the southgive way to the north to banded gneisses andfoliated granodiorite, which farther northgrades into slightly banded biotite grano­diorite with elongate biotite clots, and theninto equigranular granodiorite (both of

66

ROCK UNITS OLDER THAN THE SURAT BASIN

BASEMENT TO THE BOWEN BASIN

Basement in the area consists of induratedand deformed sediments, low-grade meta­sediments, acid igneous complexes, and vol­canics, whose distribution and present reliefare shown in Plate 9. In the deep parts ofthe Taroom Trough basement has not beenreached by exploratory wells. The sedi­ments, metasediments, and volcanics rangein age from Devonian to Early Permian, andare intruded by granites ranging from pos­sibly as old as Devonian to Early Triassic;the granites generally become younger tothe east, in harmony with the eastwardmigration of the Tasman Geosyncline. Themain basement rock units are summarized inTables 11 and 12.

Timbury Hills Formation (pzt)

The term 'Timbury Hills Formation' iscommonly used for all the indurated sedi­ments and metasediments that form thebasement to the west of the Mimosa Syn­cline. Late Devonian plants have beenrecovered from two wells, but as thesequence probably includes rock units of dif­ferent ages the validity of the name isdoubtful. The oldest sediments overlying thebasement are the Lower Permian ReidsDome Beds, which rest unconformably onthe Timbury Hills Formation in theArbroath Trough.

'Kuttung Formation' and equivalents (C-Pk)

All the volcanics and sediments of Car­boniferous to Early Permian age are hereincluded in the 'Kuttung Formation' ofMack (1963), despite the doubtful validityof the name. The age and relations ofthe rocks recovered in cores are uncertain,and it is not possible to identify separateunits such as the Camboon Andesite andCombarngo Volcanics.

The outcrop equivalents of the 'KuttungFormation' include the Camboon Andesiteto the west of the Auburn Complex, theYarrol Basin sequence east of the AuburnComplex, and the Texas Beds (Clt) in theTexas High.

Roma granites (Clg)'Roma granites' is the term used by

Houston (1964) for the granites penetratedby exploratory wells on the Roma Shelf.She maintained that they were probably partof the same intrusive body that underlies theother basement rocks ~n the shelf. TheRoma granites consist mainly of adamellite;they intrude the Timbury Hills Formation,which is hornfelsed in some wells (Houston,1964). The K-Ar ages obtained on samplesfrom five AAa wells range from 298 to 350m.y. (A. W. Webb, table 1 in Houston,1964 ). All the samples are weathered, so theaccuracy of the determinations is doubtful.The presence of arkosic sediments above thegranites indicates a period of subaerial ero­sion.

Auburn Complex (Cug & P-TRg)The Auburn Complex (see Mollan et al.,

1972) consists of granodiorite and minordiorite cut by dykes of dacite and andesite.The complex intrudes Palaeozoic metamor­phics and the Lower Permian CamboonAndesite; the isotopic ages obtained onsamples from the complex range from earlyLate Carboniferous to early Late Permian(311-240 m.y.). The results suggest thatthe complex consists of a western Carboni­ferous body (Cug) and an eastern UpperPermian to Triassic body (P-TRg) (Webb &McDougall, 1968) which were mapped byWhitaker, Murphy, & Rollason (1974). Thecomplex is unconformably overlain byLower Jurassic sediments.

Yarraman Complex (pzm & P-TRg)The Yarraman Complex (see Exon et al.,

1968) consists of foliated acid rocks (pzm)in the south, and massive granodiorite(P-TRg) in the north.

The grade of metamorphism of thefoliated acid rocks (pzm) increases to thenorth. The schists and phyllites in the southgive way to the north to banded gneisses andfoliated granodiorite, which farther northgrades into slightly banded biotite grano­diorite with elongate biotite clots, and theninto equigranular granodiorite (both of

TABLE 11. PRE-BOWEN BASIN STRATIGRAPHY

Nwne(map symbol)

Thickness(m)

Lithology Fossils and Environ­ment of Deposition

Relations MainReferences

Lower Permian CamboonAndesite

(Pln)

3000± Andesitic and dacitic weldedtuff and flows; minor basalt,rhyolite and agglomerate

Plants. Terrestrial andshallow marine

Intruded by Auburn Granite; con­formably overlain by Permiansediments

Mollan et al. (1972,pp. 19-20),Whitaker et al.(1974, pp. 32-3)

Interbedded lithic sandstoneand mudstone, shale, minorchert, jasper, fossiliferouslimestone, andesite, intrafor­mational conglomerate

PyrocIastics, lavas, sandstone,sillstone, shale, oolitic sand­stone, calearenite, recrystal­lized limestone, massiveconglomerate

Tuff, andesite, dacite, silt­stone, sandstone, conglom­erate, shale

Mack (1963)

Derrington (1961 ) ,Traves (1966)

Maxwell in Hill &Denmead (1960, pp.160-2), Exan et al.(1968)

FloodOlgers &(1974 )

Intruded by Permo-Triassic gran­ites; unconformably overlie L.Devonian sequence; unconform­ably overlain by Permian andMesozoic sediments

Intruded by Triassic granites; un­conformably overlain by L. Juras­sic sediments

Blanket term embracing subsur­face Cracow Fm, Camboon An­desite, Combarngo Vole, TexasBeds, and Yarrol Basin sequence.Unconformably overlain by L.Jurassic sediments

Blanket term for all induratedsubsurface sediments and meta­sediments in basement. Intrudedby Roma granites; unconformablyoverlain by L. Permian andyounger sediments

Plants. Mainly terres­trial

Shelly fossils. Shallowmarine

Corals, brachiopods,bryozoans, crinoids.Shallow marine, be­low and above wavebase

Corals, bryozoans,brachiopods. Shallowmarine and possiblyterrestrial

sillstane, shalemetamorphosed

Sandstone,and theirequivalents

1000+

Probablythousandsof metres

Probablythousandsof metres

Probablythousandsof metres

TimburyHillsFormation

(Pzt)

Texas Beds(Cll)

'KullungFormation'

(C-Pk)

Yarrol Basinsequence

(D, Cl, Cu)

Lower Carbon­iferous (possiblyranges into U.Devonian and U.Carboniferous)

Devanian toCarboniferous

Devonian atleast

Carboniferousto LowerPermian

TABLE 11. PRE-BOWEN BASIN STRATIGRAPHY

Nwne(map symbol)

Thickness(m)

Lithology Fossils and Environ­ment of Deposition

Relations MainReferences

Lower Permian CamboonAndesite

(Pln)

3000± Andesitic and dacitic weldedtuff and flows; minor basalt,rhyolite and agglomerate

Plants. Terrestrial andshallow marine

Intruded by Auburn Granite; con­formably overlain by Permiansediments

Mollan et al. (1972,pp. 19-20),Whitaker et al.(1974, pp. 32-3)

Interbedded lithic sandstoneand mudstone, shale, minorchert, jasper, fossiliferouslimestone, andesite, intrafor­mational conglomerate

PyrocIastics, lavas, sandstone,sillstone, shale, oolitic sand­stone, calearenite, recrystal­lized limestone, massiveconglomerate

Tuff, andesite, dacite, silt­stone, sandstone, conglom­erate, shale

Mack (1963)

Derrington (1961 ) ,Traves (1966)

Maxwell in Hill &Denmead (1960, pp.160-2), Exan et al.(1968)

FloodOlgers &(1974 )

Intruded by Permo-Triassic gran­ites; unconformably overlie L.Devonian sequence; unconform­ably overlain by Permian andMesozoic sediments

Intruded by Triassic granites; un­conformably overlain by L. Juras­sic sediments

Blanket term embracing subsur­face Cracow Fm, Camboon An­desite, Combarngo Vole, TexasBeds, and Yarrol Basin sequence.Unconformably overlain by L.Jurassic sediments

Blanket term for all induratedsubsurface sediments and meta­sediments in basement. Intrudedby Roma granites; unconformablyoverlain by L. Permian andyounger sediments

Plants. Mainly terres­trial

Shelly fossils. Shallowmarine

Corals, brachiopods,bryozoans, crinoids.Shallow marine, be­low and above wavebase

Corals, bryozoans,brachiopods. Shallowmarine and possiblyterrestrial

sillstane, shalemetamorphosed

Sandstone,and theirequivalents

1000+

Probablythousandsof metres

Probablythousandsof metres

Probablythousandsof metres

TimburyHillsFormation

(Pzt)

Texas Beds(Cll)

'KullungFormation'

(C-Pk)

Yarrol Basinsequence

(D, Cl, Cu)

Lower Carbon­iferous (possiblyranges into U.Devonian and U.Carboniferous)

Devanian toCarboniferous

Devonian atleast

Carboniferousto LowerPermian

TABLE 12. PRE-BOWEN BASIN IGNEOUS AND METAMORPHIC ROCKS

Name(map symbol)

Upper Permian (P-TRg)to Lower Triassic(stratigraphicgrounds)

Upper Permian (P-TRg)(isotopicgrounds)

Upper Carbon- Auburniferous to Lower GranitePermian (isotopic (Cug,and stratigraphic P-TRg)grounds

Lower Carbon- Romaiferous (isotopic granitesgrounds) (Clg)

Devonian? (Dg)

Mid-Palaeozoic (Pzm)

Lower Palaeozoic (pzr)(stratigraphicgrounds)

Palaeozoic (pzs)

Location

Texas area (in SE partof map)

W of Proston (in Epart of map)

Between Cracow andEidsvold (in NE partof map)

Roma area (subsurface)

Talwood area (in Spart of map). (subsur­face)

SE of Durong (in Epart of map)

Asbestos Gully (in NWpart of map).

S of Morven (in W partof map) and near StGeorge (in SW part ofmap). (subsurface)

Lithology

Massive granite and grano­diorite

Massive hornblende-biotitegranite grading into grano­diorite; acid to basic dykes

Hornblende-biotite granitegrading into granodiorite;acid to basic dykes

Micaceous granite and ada­mellite in several discontinu­ous bodies

Granite, granodiorite, dolerite

Schist, gneiss, foliated grano­diorite; minor phyllite, acidto basic dykes; grade ofmetamorphism increases to N

Mainly sheared gabbro; somealtered ultrabasic rocks,chlorite rock, and tremoliteveins

Schist, gneiss

Relations

Intrudes Carboniferous Texas Beds;unconformably overlain by L.Jurassic strata

Part of Yarraman Block; geneticrelations with contiguous meta­morphic rocks (Pzm) unknown,although contact is generally grada­tional; intrudes Carboniferous rocks

Part of Auburn Complex; intrudesPalaeozoic metamorphics and L.Permian Camboon Andesite to N;unconformably overlain by L.Jurassic strata

Intrude and thermally metamor­phose L. Palaeozoic Timbury HillsFm; unconformably overlain by M.Triassic and younger strata

Unconformably overlain by L.Jurassic sequence

Part of Yarraman Block; generallygradational contact with P-TRg gran­ite; unconformably overlain by L.Jurasisc sequence

Unconformably overlain by Triassic(or older) rocks

Unconformably overlain by Jurassicsequence

MainReferences

'Ashford granite' of Lucasin Hill & Denmead eds(1960, p. 233)

Hill & Denmead eds (1960,pp. 245-9), Exon et aI.,(1968), Webb & McDougall(1968)

Mollan et al. (1972, pp.74-6), Webb & McDougall(1968)

Houston (1964)

Exon et al. (1968)

Mollan et al. (1972, p. 12)

TABLE 12. PRE-BOWEN BASIN IGNEOUS AND METAMORPHIC ROCKS

Name(map symbol)

Upper Permian (P-TRg)to Lower Triassic(stratigraphicgrounds)

Upper Permian (P-TRg)(isotopicgrounds)

Upper Carbon- Auburniferous to Lower GranitePermian (isotopic (Cug,and stratigraphic P-TRg)grounds

Lower Carbon- Romaiferous (isotopic granitesgrounds) (Clg)

Devonian? (Dg)

Mid-Palaeozoic (Pzm)

Lower Palaeozoic (pzr)(stratigraphicgrounds)

Palaeozoic (pzs)

Location

Texas area (in SE partof map)

W of Proston (in Epart of map)

Between Cracow andEidsvold (in NE partof map)

Roma area (subsurface)

Talwood area (in Spart of map). (subsur­face)

SE of Durong (in Epart of map)

Asbestos Gully (in NWpart of map).

S of Morven (in W partof map) and near StGeorge (in SW part ofmap). (subsurface)

Lithology

Massive granite and grano­diorite

Massive hornblende-biotitegranite grading into grano­diorite; acid to basic dykes

Hornblende-biotite granitegrading into granodiorite;acid to basic dykes

Micaceous granite and ada­mellite in several discontinu­ous bodies

Granite, granodiorite, dolerite

Schist, gneiss, foliated grano­diorite; minor phyllite, acidto basic dykes; grade ofmetamorphism increases to N

Mainly sheared gabbro; somealtered ultrabasic rocks,chlorite rock, and tremoliteveins

Schist, gneiss

Relations

Intrudes Carboniferous Texas Beds;unconformably overlain by L.Jurassic strata

Part of Yarraman Block; geneticrelations with contiguous meta­morphic rocks (Pzm) unknown,although contact is generally grada­tional; intrudes Carboniferous rocks

Part of Auburn Complex; intrudesPalaeozoic metamorphics and L.Permian Camboon Andesite to N;unconformably overlain by L.Jurassic strata

Intrude and thermally metamor­phose L. Palaeozoic Timbury HillsFm; unconformably overlain by M.Triassic and younger strata

Unconformably overlain by L.Jurassic sequence

Part of Yarraman Block; generallygradational contact with P-TRg gran­ite; unconformably overlain by L.Jurasisc sequence

Unconformably overlain by Triassic(or older) rocks

Unconformably overlain by Jurassicsequence

MainReferences

'Ashford granite' of Lucasin Hill & Denmead eds(1960, p. 233)

Hill & Denmead eds (1960,pp. 245-9), Exon et aI.,(1968), Webb & McDougall(1968)

Mollan et al. (1972, pp.74-6), Webb & McDougall(1968)

Houston (1964)

Exon et al. (1968)

Mollan et al. (1972, p. 12)

which are included in unit P-TRg). Thus theboundary between the units is gradational.

The granodiorites (P-TRg) intrude theCarboniferous volcanics and sediments ofthe Yarrol Basin sequence; copper mineral­ization is present near the contact. Acidigneous rocks belonging to the same suite ofintrusions farther east were dated as LatePermian by Webb &McDougall (1968).

The relations between the massive grano­diorites and the metamorphics is obscure.Although the contacts are generally gra­dational, some of the small granodioritebodies in the metamorphics (pzm) havesharp intrusive contacts. It is possible thatthe foliated acid rocks (pzm) representdownfolded Lower Palaeozoic or mid­Palaeozoic rocks that were granitized andpartly mobilized in the Permian to form theintrusives (P-TRg).

Texas High granite (P-TRg)The Upper Permian to Triassic granites

of the New England Batholith are intrusiveinto the Permo-Carboniferous sequence ofthe Texas High. The intrusives have beendescribed in some detail by Robertson(1974), who assigns the granite west ofTexas to the Late Permian or Early Triassic,and the granites south of Yuraraba to theEarly Triassic. The PS Millmerran No. 1well bottomed in granite that is alsoprobably a northerly offshoot of the NewEngland Batholith.

Other igneous intrusivesOther large bodies of granite (see Fig. 7)

of uncertain age, which are presumed to beintrusives into the Timbury Hills or 'KuttungFormation', or both, form the basement nearTalwood (Dg), south of Mungallala, andnorth of Mitchell. The Mungallala granite isflanked by schist and gneiss; schists andgneisses also form basement at St George.

A small body of sheared gabbro andpyroxenite (Pzr), which crops out at Asbes­tos Gully on the Nebine Ridge, may be in­trusive into the Timbury Hills Formation. Itis unconformably overlain by pre-Jurassicsediments, and plagioclase from the gabbrohas yielded an Early Palaeozoic K-Ar age(A. Webb, pers comm.). A zone of sharpmagnetic anomalies along the crest of the

69

Nebine Ridge is probably due to a continua­tion of these basic and ultrabasic rocks in thesubsurface (Magellan Petroleum Corp.,1963, p. 13).

BOWEN BASIN ROCKS

The Permian and Triassic rocks croppingout in the Bowen Basin have been describedby Mollan, Dickins, Exon, & Kirkegaard( 1969), Mollan et al. (1972), and Dickins& Malone ( 1973 ). A summary of thenomenclature used in various areas and thepreferred correlations from area to area aregiven in Table 13, and brief descriptions ofthe various units in Tables 14 and 17.

Four thousand metres of Permian sedi­ments (mainly marine) and 5500 ID ofTriassic rocks (mainly freshwater) werelaid down in the Taroom Trough, and athick sequence of Permian rocks was alsodeposited in the Denison Trough. The 4000m of Permian sediments and 5500 m ofTriassic sediments represent accumulationrates of 13 and 27 cm per 1000 yearsrespectively (Table 15), which indicatefairly rapid subsidence in these troughsthroughout the Permo-Triassic period.

PERMIAN SEQUENCE NORTH OF SURAT

BASIN

The Permian sequence in the DenisonTrough (Table 14) consists of 2500 m ofLower Permian (Sakmarian) stream andswamp deposits (Reids Dome Beds), up to2000 m of Lower to Upper Permian marinesediments (Back Creek Group), and 150 mof Upper Permian (Tartarian) coal measures(Blackwater Group). The Back CreekGroup has been subdivided into the Tiverton(750 m) and Gebbie (700 m) Sub-groupsand the relatively thin Blenheim Sub-group(300 m).

Farther east in the Taroom Trough nearCracow, over 1000 m of Sakmarian terres­tial volcanic rocks of the Camboon Andesiteare overlain by some 2000 m of Lower toUpper Permian marine sediments of theBack Creek Group and 800 m of the Tar­tarian Blackwater Group coal measures. TheTiverton and Gebbie Sub-groups of th~ BackCreek Group are relatively thin (200 m andnegligible) in the Cracow area, whereas the

which are included in unit P-TRg). Thus theboundary between the units is gradational.

The granodiorites (P-TRg) intrude theCarboniferous volcanics and sediments ofthe Yarrol Basin sequence; copper mineral­ization is present near the contact. Acidigneous rocks belonging to the same suite ofintrusions farther east were dated as LatePermian by Webb &McDougall (1968).

The relations between the massive grano­diorites and the metamorphics is obscure.Although the contacts are generally gra­dational, some of the small granodioritebodies in the metamorphics (pzm) havesharp intrusive contacts. It is possible thatthe foliated acid rocks (pzm) representdownfolded Lower Palaeozoic or mid­Palaeozoic rocks that were granitized andpartly mobilized in the Permian to form theintrusives (P-TRg).

Texas High granite (P-TRg)The Upper Permian to Triassic granites

of the New England Batholith are intrusiveinto the Permo-Carboniferous sequence ofthe Texas High. The intrusives have beendescribed in some detail by Robertson(1974), who assigns the granite west ofTexas to the Late Permian or Early Triassic,and the granites south of Yuraraba to theEarly Triassic. The PS Millmerran No. 1well bottomed in granite that is alsoprobably a northerly offshoot of the NewEngland Batholith.

Other igneous intrusivesOther large bodies of granite (see Fig. 7)

of uncertain age, which are presumed to beintrusives into the Timbury Hills or 'KuttungFormation', or both, form the basement nearTalwood (Dg), south of Mungallala, andnorth of Mitchell. The Mungallala granite isflanked by schist and gneiss; schists andgneisses also form basement at St George.

A small body of sheared gabbro andpyroxenite (Pzr), which crops out at Asbes­tos Gully on the Nebine Ridge, may be in­trusive into the Timbury Hills Formation. Itis unconformably overlain by pre-Jurassicsediments, and plagioclase from the gabbrohas yielded an Early Palaeozoic K-Ar age(A. Webb, pers comm.). A zone of sharpmagnetic anomalies along the crest of the

69

Nebine Ridge is probably due to a continua­tion of these basic and ultrabasic rocks in thesubsurface (Magellan Petroleum Corp.,1963, p. 13).

BOWEN BASIN ROCKS

The Permian and Triassic rocks croppingout in the Bowen Basin have been describedby Mollan, Dickins, Exon, & Kirkegaard( 1969), Mollan et al. (1972), and Dickins& Malone ( 1973 ). A summary of thenomenclature used in various areas and thepreferred correlations from area to area aregiven in Table 13, and brief descriptions ofthe various units in Tables 14 and 17.

Four thousand metres of Permian sedi­ments (mainly marine) and 5500 ID ofTriassic rocks (mainly freshwater) werelaid down in the Taroom Trough, and athick sequence of Permian rocks was alsodeposited in the Denison Trough. The 4000m of Permian sediments and 5500 m ofTriassic sediments represent accumulationrates of 13 and 27 cm per 1000 yearsrespectively (Table 15), which indicatefairly rapid subsidence in these troughsthroughout the Permo-Triassic period.

PERMIAN SEQUENCE NORTH OF SURAT

BASIN

The Permian sequence in the DenisonTrough (Table 14) consists of 2500 m ofLower Permian (Sakmarian) stream andswamp deposits (Reids Dome Beds), up to2000 m of Lower to Upper Permian marinesediments (Back Creek Group), and 150 mof Upper Permian (Tartarian) coal measures(Blackwater Group). The Back CreekGroup has been subdivided into the Tiverton(750 m) and Gebbie (700 m) Sub-groupsand the relatively thin Blenheim Sub-group(300 m).

Farther east in the Taroom Trough nearCracow, over 1000 m of Sakmarian terres­tial volcanic rocks of the Camboon Andesiteare overlain by some 2000 m of Lower toUpper Permian marine sediments of theBack Creek Group and 800 m of the Tar­tarian Blackwater Group coal measures. TheTiverton and Gebbie Sub-groups of th~ BackCreek Group are relatively thin (200 m andnegligible) in the Cracow area, whereas the

TABLE 13. NOMENCLATURE AND CORRELATES, SOUTHERN PART OF BOWEN BASIN

Union/ Kern!This Bulletin

Mollan et al. (1972) Jensen (in press) AOGSouthern part Mines

SE part of Bowen SE part of BowenSouthern part

of Taroom This Bulletin AdministrationMollan et al. (1972) SW part

Basin (e.g. Theodore- Basin (Theodore- of Tarooll1Trough Roma Shelf Pty Lld

of Bowen Basin

Cracow area) Cracow area) Trough (beneath RomaShelf(e.g. Denison Trough)

(beneathSurat Basin) Surat Basin)

Moolayember Moolayember Moolayember Moolayember Moolayember (j

'Formation Formation Formation Formation Formation .~

Wandaan Wandoan "'':;Clematis Expedi- Showgrounds Showgrounds ...Sandstone tion* Clematis Sandstone Sandstone Clematis .,

:aSandstone .",

--D--D Formation Formation -U-U-U-U-U-U-U-U-l -u-u-u-u-u-u-u-u-u-u ~Glenidal Group No deposits No deposits Sandstone I---

Rewan Formation (j

u-u-u-u-u-u-u-u-u-u p-u-u-u-u-u-u-u-u-u u-u-u-u-u-u-u-u-u- -u-u-u-u-u-u- D D D .~

"Arcadia Rewan Rewan '':;

Formation ...Cabawin Group Rewan Rewan Rewan ...

Formation Formation (=Cabawin Group Formation Formation .,Sagittarius ~

Group Formation) 0Sandstone ...l

-u-u-u-u-u-u-u-u -u-u-u-u-u-u

Baralaba Coal Kianga Blackwater Blackwater Bandana Blackwater cMeasures Formation Group Group Formation Group "'§Gyranda Formation .,

Black Alley Black AlleyQ.,

Back ...Shale Shale Blenheim .,

Cl.Cl.

Back Back Back Tinowon Peawaddy :>Creek Formation Formation Sub-Group

Creek Creek Creek Muggleton Catherine SstGroup -Ingelara GebbieFormation Formation c

Group Group Group "n-n-n-n-n-n-n-n-n -U-U-U-U-U-U-U-U-U-l ·sAldebaran SUb-Group ....,Sandstone Q.,

...Cattle Creek Tiverton ~Formation SUb-Group 0

...l

Reids Dome Beds

* In thiS area probably the Dawson Range Sandstone of Reld (1945).D = disconformityu = unconformity

TABLE 13. NOMENCLATURE AND CORRELATES, SOUTHERN PART OF BOWEN BASIN

Union/ Kern!This Bulletin

Mollan et al. (1972) Jensen (in press) AOGSouthern part Mines

SE part of Bowen SE part of BowenSouthern part

of Taroom This Bulletin AdministrationMollan et al. (1972) SW part

Basin (e.g. Theodore- Basin (Theodore- of Tarooll1Trough Roma Shelf Pty Lld

of Bowen Basin

Cracow area) Cracow area) Trough (beneath RomaShelf(e.g. Denison Trough)

(beneathSurat Basin) Surat Basin)

Moolayember Moolayember Moolayember Moolayember Moolayember (j

'Formation Formation Formation Formation Formation .~

Wandaan Wandoan "'':;Clematis Expedi- Showgrounds Showgrounds ...Sandstone tion* Clematis Sandstone Sandstone Clematis .,

:aSandstone .",

--D--D Formation Formation -U-U-U-U-U-U-U-U-l -u-u-u-u-u-u-u-u-u-u ~Glenidal Group No deposits No deposits Sandstone I---

Rewan Formation (j

u-u-u-u-u-u-u-u-u-u p-u-u-u-u-u-u-u-u-u u-u-u-u-u-u-u-u-u- -u-u-u-u-u-u- D D D .~

"Arcadia Rewan Rewan '':;

Formation ...Cabawin Group Rewan Rewan Rewan ...

Formation Formation (=Cabawin Group Formation Formation .,Sagittarius ~

Group Formation) 0Sandstone ...l

-u-u-u-u-u-u-u-u -u-u-u-u-u-u

Baralaba Coal Kianga Blackwater Blackwater Bandana Blackwater cMeasures Formation Group Group Formation Group "'§Gyranda Formation .,

Black Alley Black AlleyQ.,

Back ...Shale Shale Blenheim .,

Cl.Cl.

Back Back Back Tinowon Peawaddy :>Creek Formation Formation Sub-Group

Creek Creek Creek Muggleton Catherine SstGroup -Ingelara GebbieFormation Formation c

Group Group Group "n-n-n-n-n-n-n-n-n -U-U-U-U-U-U-U-U-U-l ·sAldebaran SUb-Group ....,Sandstone Q.,

...Cattle Creek Tiverton ~Formation SUb-Group 0

...l

Reids Dome Beds

* In thiS area probably the Dawson Range Sandstone of Reld (1945).D = disconformityu = unconformity

TABLE 14. PERMIAN STRATIGRAPHY, BOWEN BASIN

MaximumName Thickness Lithology Fossils Environment of

(map symbol! (m) Deposition

Upper Blackwater 800 in Taroom Carbonaceous shale, Glossopteris flora Mainly terrestrial :Permian Group Trough, 250 be- siltstone, lithic to and spores (acTi- streams, lakes, and

(Puw) neath Surat Basin, lithic sublabile sand- tarchs at base in coal swampsISO in Denison stone, coal; some same areas)Trough area tuff in S

Lower to Back Creek 2000 in Denison Shale, siltstone, Shelly faunas 11, Dominantly shal-Upper Group Trough, and be- sandstone, conglom- Ill, and IV, low marine, grad-Permian (Pb) neath N part of erate, coal; some Glossopteris flora, ing intO' coastal

Surat Basin tuff in S. Minor spores and acri- plain and deltaiclimestone tarchs

Upper B1enheim 1500 in Baralaba Shale, siltstone, Shelly fauna IV, Swamps, coastalPermian Sub-Group area, 300 in Deni- lithic sublabile sand- Glossopteris flora, plains, shallow

son Trough area stone; some clay, spores and acri- seas; marine in-bentonite, tuff, and tarchs, rare fish fluence diminishedcoquinite scales as time went on

Gebbie 700 in Denison Sandstone, siltstone, Shelly fauna 1II, Moderately deepSub-Group Trough. Absent in mudstone; some Glossopteris flora, marine to coastal

Cracow area tuff, coquinite, and spores plain; dominantlycoal shallow marine.

Cold water; someice rafting ofcobbles and boul-ders. Some explos-ive volcanism

LowerPermian Cattle 500 (Cattle Creek), Conglomeratic silt· Shelly fauna 11, Marine, somewhat

Creek 7S0 (Tiverton Sub- stone, sandy mud· characterized by restricted. VeryFormation Gp) in Denison stone, sandstone, Eurydesma; Glos- cold water; ice

Trough. 200 coquinitic limestone sopteris flora rafting of cobblesTiverton (Tiverton Sub-Gp) and boulders

Sub.Group) in Cracow area

Reids Dome 2S00 in Denison Polymictic eonglo- Glossopteris flora, Streams, lakes,Beds Trough, 1100 in merate, sandstone, spores and coal swamps

(Plj) Arbroath Trough siltstone, shale;some coal

Relations

Equivalent to Barralaba CoalMeas and Gyranda Fm in farN. Not readily divisible be­neath Sural Basin. Minad'sBandanna Fm of Roma Shelf.Union's Kianga Fm in S

Conformably overlies ReidsDome Beds in Dension andArbroath Troughs. Uncon­formably overlies older unitsbeneath Sural Basin, where itis not readily divisible

Uppermost sub-gp of BackCreek Gp. Split into BlackAlley Sh and Tinowan Fm onRoma Shelf by Minad. Con­formable on older Permiansediments

Middle sub-gp of Back CreekGp. Represented by Minad'sMuggleton Fm on RomaShelf. Conformable on olderPermian sediments, uncon­formable on basement

Only reptesentative of Tiver­ton Sub-Gp in this area (low­est sub-gp of Back CreekGroup). ConfIned to DenisonTrough. Conformable onReids Dome Beds

Virtually confined to' Denisonand Arbroath Troughs. Un­conformable on basementrocks

MainReferences

Malone, Olgers,& Kirkegaard(1969), Mollanel al. (1972),Dickins &Malone (1973)

Derrington,Glover, &Morgan (1959),Dickins &Malone (1973)

Dickins &Malone (1973)

Mollan et al.( 1969) , Dickins& Malone (1973)

Mollan et al.(1969)

Mollan et aI.(1969)

....

TABLE 14. PERMIAN STRATIGRAPHY, BOWEN BASIN

MaximumName Thickness Lithology Fossils Environment of

(map symbol! (m) Deposition

Upper Blackwater 800 in Taroom Carbonaceous shale, Glossopteris flora Mainly terrestrial :Permian Group Trough, 250 be- siltstone, lithic to and spores (acTi- streams, lakes, and

(Puw) neath Surat Basin, lithic sublabile sand- tarchs at base in coal swampsISO in Denison stone, coal; some same areas)Trough area tuff in S

Lower to Back Creek 2000 in Denison Shale, siltstone, Shelly faunas 11, Dominantly shal-Upper Group Trough, and be- sandstone, conglom- Ill, and IV, low marine, grad-Permian (Pb) neath N part of erate, coal; some Glossopteris flora, ing intO' coastal

Surat Basin tuff in S. Minor spores and acri- plain and deltaiclimestone tarchs

Upper B1enheim 1500 in Baralaba Shale, siltstone, Shelly fauna IV, Swamps, coastalPermian Sub-Group area, 300 in Deni- lithic sublabile sand- Glossopteris flora, plains, shallow

son Trough area stone; some clay, spores and acri- seas; marine in-bentonite, tuff, and tarchs, rare fish fluence diminishedcoquinite scales as time went on

Gebbie 700 in Denison Sandstone, siltstone, Shelly fauna 1II, Moderately deepSub-Group Trough. Absent in mudstone; some Glossopteris flora, marine to coastal

Cracow area tuff, coquinite, and spores plain; dominantlycoal shallow marine.

Cold water; someice rafting ofcobbles and boul-ders. Some explos-ive volcanism

LowerPermian Cattle 500 (Cattle Creek), Conglomeratic silt· Shelly fauna 11, Marine, somewhat

Creek 7S0 (Tiverton Sub- stone, sandy mud· characterized by restricted. VeryFormation Gp) in Denison stone, sandstone, Eurydesma; Glos- cold water; ice

Trough. 200 coquinitic limestone sopteris flora rafting of cobblesTiverton (Tiverton Sub-Gp) and boulders

Sub.Group) in Cracow area

Reids Dome 2S00 in Denison Polymictic eonglo- Glossopteris flora, Streams, lakes,Beds Trough, 1100 in merate, sandstone, spores and coal swamps

(Plj) Arbroath Trough siltstone, shale;some coal

Relations

Equivalent to Barralaba CoalMeas and Gyranda Fm in farN. Not readily divisible be­neath Sural Basin. Minad'sBandanna Fm of Roma Shelf.Union's Kianga Fm in S

Conformably overlies ReidsDome Beds in Dension andArbroath Troughs. Uncon­formably overlies older unitsbeneath Sural Basin, where itis not readily divisible

Uppermost sub-gp of BackCreek Gp. Split into BlackAlley Sh and Tinowan Fm onRoma Shelf by Minad. Con­formable on older Permiansediments

Middle sub-gp of Back CreekGp. Represented by Minad'sMuggleton Fm on RomaShelf. Conformable on olderPermian sediments, uncon­formable on basement

Only reptesentative of Tiver­ton Sub-Gp in this area (low­est sub-gp of Back CreekGroup). ConfIned to DenisonTrough. Conformable onReids Dome Beds

Virtually confined to' Denisonand Arbroath Troughs. Un­conformable on basementrocks

MainReferences

Malone, Olgers,& Kirkegaard(1969), Mollanel al. (1972),Dickins &Malone (1973)

Derrington,Glover, &Morgan (1959),Dickins &Malone (1973)

Dickins &Malone (1973)

Mollan et al.( 1969) , Dickins& Malone (1973)

Mollan et al.(1969)

Mollan et aI.(1969)

....

TABLE 15. MAXIMUM RATES OF SEDIMENT ACCUMULATION FOR VARIOUS STRATIGRAPHIC INTERVALS

Maximum Maximum Rate of AccumulationSequence Age Environment of Time Span Thickness of Consolidated sediment

Deposition (m.y.) (m) (m/ms.) (cm/lOOO y.)

Cainozoic sediments Cainozoic Streams 65? 250 4? 0.4?

No sediments preserved Late Cretaceous 38 0 0

Coreena Member and Griman Marine and streams 4 850 210 21Creek FmDoncaster Member Early Cretaceous Marine 4 270· 70 7Minmi Member Shallow marine 2? 80 40? 4?Mooga Sst and Nullawurt Sst Streams 24? 430 18? 1.8?

Springbrook Sst and Orallo Streams and swamps 24 lOOO 40 4FmWalloon Coal Measures Swamps and streams 10 650· 65 6.5U. part of Evergreen Fm, and Jurassic Streams and deltas lO 370 40 4Hutton SstPrecipe Sst and L. part of Streams and deltas 19 390 20 2Evergreen Fm

No sediments preserved Late Triassic 20 0 0

Clematis Gp and Moolayem- Streams and deltas lO 2000 200 20ber Fm E-M TriassicRewan Group Streams 10 3500 350 35

Blackwater Group Swamps and streams 10 700· 70 7Back Creek Group Permian Marine 20 3500? 170? 17?Reids Dome Beds Streams 5 2500 500 50

MAJOR SUBDIVISIONS

Cainozoic Streams 65? 250 4? 0.4?Marine Cretaceous Marine and streams 8 1200· 150 15Freshwater Cretaceous Streams 24? 430 18? 2?Jurassic Streams and deltas 60 2400 40 4

Total Surat Basin Jurassic- Varied 95 4000 40 4Cretaceous

Triassic Streams 20 5500 270 27post-volcanic Permian Marine and coal 30 40oo? 130? 13?

measures

Total Bowen Basin Permian-Triassic Varied 50 9500 190 19

* Compaction greater than normal.

TABLE 15. MAXIMUM RATES OF SEDIMENT ACCUMULATION FOR VARIOUS STRATIGRAPHIC INTERVALS

Maximum Maximum Rate of AccumulationSequence Age Environment of Time Span Thickness of Consolidated sediment

Deposition (m.y.) (m) (m/ms.) (cm/lOOO y.)

Cainozoic sediments Cainozoic Streams 65? 250 4? 0.4?

No sediments preserved Late Cretaceous 38 0 0

Coreena Member and Griman Marine and streams 4 850 210 21Creek FmDoncaster Member Early Cretaceous Marine 4 270· 70 7Minmi Member Shallow marine 2? 80 40? 4?Mooga Sst and Nullawurt Sst Streams 24? 430 18? 1.8?

Springbrook Sst and Orallo Streams and swamps 24 lOOO 40 4FmWalloon Coal Measures Swamps and streams 10 650· 65 6.5U. part of Evergreen Fm, and Jurassic Streams and deltas lO 370 40 4Hutton SstPrecipe Sst and L. part of Streams and deltas 19 390 20 2Evergreen Fm

No sediments preserved Late Triassic 20 0 0

Clematis Gp and Moolayem- Streams and deltas lO 2000 200 20ber Fm E-M TriassicRewan Group Streams 10 3500 350 35

Blackwater Group Swamps and streams 10 700· 70 7Back Creek Group Permian Marine 20 3500? 170? 17?Reids Dome Beds Streams 5 2500 500 50

MAJOR SUBDIVISIONS

Cainozoic Streams 65? 250 4? 0.4?Marine Cretaceous Marine and streams 8 1200· 150 15Freshwater Cretaceous Streams 24? 430 18? 2?Jurassic Streams and deltas 60 2400 40 4

Total Surat Basin Jurassic- Varied 95 4000 40 4Cretaceous

Triassic Streams 20 5500 270 27post-volcanic Permian Marine and coal 30 40oo? 130? 13?

measures

Total Bowen Basin Permian-Triassic Varied 50 9500 190 19

* Compaction greater than normal.

73

TABLE 16. PERMIAN BACK CREEK GROUP STRATIGRAPHY, ROMA SHELF.

Maximum DepositionalUnit observed Environment Lithology

Thickness (m)

BLACK ALLEY 60 LACUSTRINE DARK CARBONACEOUS AND TUFFACEOUSSHALE AND SILTSTONE

IWinnathoolaI TO IPaludal THIN~J:20 TUFF Black. and brown coal, carbonaceous shale

Coal Mbr BAND and stltstone

SHALE MARINE AND MINOR SANDSTONE

IMantuan I 30 IMarine ICOQUinitic shale, siltstone and sandstoneProductus Bed

GREY TUFFACEOUS SHALE AND SILT-TINOWON 124 PARALIC STONE, MINOR SANDSTONE, THIN TUFF

BANDS

IWallabella I 31 IPaludal 1~lack coal, carbonaceous shale and silt-Coal Mbr stone

FORMATION RARE COAL SEAMSMARINE FOSSILS COMMON

MUGGLETON 148 PARALIC GREY SHALE, SILTSTONE AND SAND-STONE, FEW COQUINITES,

ILorelle I 62 TO IMarine ~oarSe-grained quarlzose sandstoneSandstone Mbr

FORMATION MARINE TUFF BANDS, AND COAL SEAMS

Blenheim Sub-group is relatively thick (1700m).

These figures are based on the correlationsof Mollan et al. (1972) and Dickins &Malone (1973), which differ from those ofAnderson (1971), who maintains that theupper part of the Back Creek Group asdefined by the BMR in the Denison Troughis the lower part of the type BlackwaterGroup in the Taroom Trough. The standardBMR correlations are as shown in Table 10.

Comparison of the sequences in the twoareas shows that the area of maximum Per­mian deposition moved eastward from theDenison Trough in Blenheim Sub-grouptime.

Farther south, beneath the Surat Basin,the Permian sequence on the Roma Shelfand the Taroom Trough is thinner.

PERMIAN SEQUENCE ON ROMA SHELF

On the Roma Shelf, where the sequenceconsists of the Reids Dome Beds, the upperpart of the Back Creek Group, and the

Blackwater Group, the stratigraphy has beenstudied in detail by geologists of MinesAdministration Pty Ltd. The results havebeen published in summary form by Traves( 1966, 1971) and Swindon (1968), onwhich the following description is mainlybased.

Reids Dome BedsThe Lower Permian Reids Dome Beds

are preserved only in the half-graben of theArbroath Trough, where they are about1100 m thick. The Arbroath Fault does notcut the unconformably-overlying LowerJurassic sediments, and is therefore of pre­Jurassic age. The absence of Triassic andpost-Sakmarian Permian sediments in thetrough suggests that active movement on thefault and subsidence of the half-graben wererestricted to the Early Permian.

The Reids Dome Beds consist of coalmeasures that contain detrital sedimentsranging from polymictic conglomerate toshale. The measures were probably laid

73

TABLE 16. PERMIAN BACK CREEK GROUP STRATIGRAPHY, ROMA SHELF.

Maximum DepositionalUnit observed Environment Lithology

Thickness (m)

BLACK ALLEY 60 LACUSTRINE DARK CARBONACEOUS AND TUFFACEOUSSHALE AND SILTSTONE

IWinnathoolaI TO IPaludal THIN~J:20 TUFF Black. and brown coal, carbonaceous shale

Coal Mbr BAND and stltstone

SHALE MARINE AND MINOR SANDSTONE

IMantuan I 30 IMarine ICOQUinitic shale, siltstone and sandstoneProductus Bed

GREY TUFFACEOUS SHALE AND SILT-TINOWON 124 PARALIC STONE, MINOR SANDSTONE, THIN TUFF

BANDS

IWallabella I 31 IPaludal 1~lack coal, carbonaceous shale and silt-Coal Mbr stone

FORMATION RARE COAL SEAMSMARINE FOSSILS COMMON

MUGGLETON 148 PARALIC GREY SHALE, SILTSTONE AND SAND-STONE, FEW COQUINITES,

ILorelle I 62 TO IMarine ~oarSe-grained quartzose sandstoneSandstone Mbr

FORMATION MARINE TUFF BANDS, AND COAL SEAMS

Blenheim Sub-group is relatively thick (1700m).

These figures are based on the correlationsof Mollan et al. (1972) and Dickins &Malone (1973), which differ from those ofAnderson (1971), who maintains that theupper part of the Back Creek Group asdefined by the BMR in the Denison Troughis the lower part of the type BlackwaterGroup in the Taroom Trough. The standardBMR correlations are as shown in Table 10.

Comparison of the sequences in the twoareas shows that the area of maximum Per­mian deposition moved eastward from theDenison Trough in Blenheim Sub-grouptime.

Farther south, beneath the Surat Basin,the Permian sequence on the Roma Shelfand the Taroom Trough is thinner.

PERMIAN SEQUENCE ON ROMA SHELF

On the Roma Shelf, where the sequenceconsists of the Reids Dome Beds, the upperpart of the Back Creek Group, and the

Blackwater Group, the stratigraphy has beenstudied in detail by geologists of MinesAdministration Pty Ltd. The results havebeen published in summary form by Traves( 1966, 1971) and Swindon (1968), onwhich the following description is mainlybased.

Reids Dome BedsThe Lower Permian Reids Dome Beds

are preserved only in the half-graben of theArbroath Trough, where they are about1100 m thick. The Arbroath Fault does notcut the unconformably-overlying LowerJurassic sediments, and is therefore of pre­Jurassic age. The absence of Triassic andpost-Sakmarian Permian sediments in thetrough suggests that active movement on thefault and subsidence of the half-graben wererestricted to the Early Permian.

The Reids Dome Beds consist of coalmeasures that contain detrital sedimentsranging from polymictic conglomerate toshale. The measures were probably laid

74

down rapidly at the foot of a scarp wherethe velocity of the streams was suddenlyreduced as they debouched from highcountry onto a swampy plain. While move­ment continued on the Merivale-ArbroathFault to the east, the plain sank, and rapiddeposition continued. After movementstopped, a thin sequence of Permo-Triassicsediments may have been laid down, but ifso it was removed during the long period ofLate Triassic erosion.

Back Creek GroupA thin sequence of marine beds represent­

ing the Back Creek Group was laid downin drowned river channels cut in the pre­Permian metamorphics and granite along theeastern margin of the Roma Shelf, most ofwhich was well above sea level (e.g. Traves,1971 ). With time the sea transgressed far­ther onto the shelf, so that the younger unitsoverlap the older. The sub-divisions of theBack Creek Group on the Roma Shelf (afterPaten & Groves, 1974) are summarizedin Table 16.

Blackwater GroupThe Blackwater Group (called Bandanna

Formation by Mines Administration geolo­gists) consists of up to 150 m of lake andswamp deposits that filled broad valleys inthe basement and in the plains of older Per­mian sediments. It laps 5 to 15 km acrossthe basement west of the Back Creek Group,generally to the longitude of Roma town(Fig. 13). The group consists mainly ofbrown and black carbonaceous shale andsiltstone, with numerous thin coal seams anda little sandstone.

PERMIAN SEQUENCES IN T AROOM TROUGH

BENEATH SURAT BASIN

The Permian sequence in the Taro0mTrough has been extensively investigated byseismic surveys and drilling by the UnionOil Development Corp. and their associates,but no regional syntheses have been pub­lished by them. The following brief descrip­tion and the structural and isopach maps(Figs 8, 13, 14) are based on data suppliedto the Commonwealth Governmt':lt underthe terms of the Petroleum Search SubsidyActs, and to the Queensland Department of

Mines on relinquishment of various parts oftheir leases (see Tables I, 2, 3).

A twofold subdivision into the marineBack Creek Group and the non-marineBlackwater Group (Kianga Formation ofUnion Oil Development Corp.) is readilymade and sustained throughout the trough.Although it is probable that all three sub­groups of the Back Creek Group, as knownin outcrop, are present in this area, detailedstudies of cores and well data would beneeded to subdivide the sequence further.

The top of the Permian sequence is 4000m below sea level near Meandarra in the axisof the Taroom Trough (Fig. 8). The troughshallows steadily to the south, and southwestof Goondiwindi its axis is 1400 m below sealevel. The Permian sequence thins from1000 m near Meandarra to 200 m nearGoondiwindi, and the two groups within italso thin in the same direction.

Back Creek GroupThe Back Creek Group consists of up to

700 m of shallow-marine deposits, and lapsonto the basement west of the TaroomTrough. East of the fault zone along theeastern side of the trough it is preserved onlyin the depression east of Moonie; its equiva­lents (PIt) are preserved in small grabenson the Texas High. The original extent ofmarine Permian sedimentary rocks east ofthe fault zone is unknown, but on the westside of the trough their present extentprobably coincides roughly with the originalarea of deposition.

The sequence in UKA Cabawin No. I,where it is nearly 400 m thick, is probablyrepresentative for most of the area. Thelower part consists of dark grey pyritic car­bonaceous and silty shale, siltstone with car­bonaceous partings, and silicified lithic sand­stone. The upper part consists of interbeddedblue-grey calcareous siltstone and shale, andlithic sandstone.

The fauna consists mainly of brachiopodsand crinoids, and the environment of deposi­tion ranged from moderately deep marine(depth of water less than 100 m) to coastalswamps. The tuffaceous material in the rockmay have been derived from older volcanics,

74

down rapidly at the foot of a scarp wherethe velocity of the streams was suddenlyreduced as they debouched from highcountry onto a swampy plain. While move­ment continued on the Merivale-ArbroathFault to the east, the plain sank, and rapiddeposition continued. After movementstopped, a thin sequence of Permo-Triassicsediments may have been laid down, but ifso it was removed during the long period ofLate Triassic erosion.

Back Creek GroupA thin sequence of marine beds represent­

ing the Back Creek Group was laid downin drowned river channels cut in the pre­Permian metamorphics and granite along theeastern margin of the Roma Shelf, most ofwhich was well above sea level (e.g. Traves,1971 ). With time the sea transgressed far­ther onto the shelf, so that the younger unitsoverlap the older. The sub-divisions of theBack Creek Group on the Roma Shelf (afterPaten & Groves, 1974) are summarizedin Table 16.

Blackwater GroupThe Blackwater Group (called Bandanna

Formation by Mines Administration geolo­gists) consists of up to 150 m of lake andswamp deposits that filled broad valleys inthe basement and in the plains of older Per­mian sediments. It laps 5 to 15 km acrossthe basement west of the Back Creek Group,generally to the longitude of Roma town(Fig. 13). The group consists mainly ofbrown and black carbonaceous shale andsiltstone, with numerous thin coal seams anda little sandstone.

PERMIAN SEQUENCES IN T AROOM TROUGH

BENEATH SURAT BASIN

The Permian sequence in the Taro0mTrough has been extensively investigated byseismic surveys and drilling by the UnionOil Development Corp. and their associates,but no regional syntheses have been pub­lished by them. The following brief descrip­tion and the structural and isopach maps(Figs 8, 13, 14) are based on data suppliedto the Commonwealth Governmt':lt underthe terms of the Petroleum Search SubsidyActs, and to the Queensland Department of

Mines on relinquishment of various parts oftheir leases (see Tables I, 2, 3).

A twofold subdivision into the marineBack Creek Group and the non-marineBlackwater Group (Kianga Formation ofUnion Oil Development Corp.) is readilymade and sustained throughout the trough.Although it is probable that all three sub­groups of the Back Creek Group, as knownin outcrop, are present in this area, detailedstudies of cores and well data would beneeded to subdivide the sequence further.

The top of the Permian sequence is 4000m below sea level near Meandarra in the axisof the Taroom Trough (Fig. 8). The troughshallows steadily to the south, and southwestof Goondiwindi its axis is 1400 m below sealevel. The Permian sequence thins from1000 m near Meandarra to 200 m nearGoondiwindi, and the two groups within italso thin in the same direction.

Back Creek GroupThe Back Creek Group consists of up to

700 m of shallow-marine deposits, and lapsonto the basement west of the TaroomTrough. East of the fault zone along theeastern side of the trough it is preserved onlyin the depression east of Moonie; its equiva­lents (PIt) are preserved in small grabenson the Texas High. The original extent ofmarine Permian sedimentary rocks east ofthe fault zone is unknown, but on the westside of the trough their present extentprobably coincides roughly with the originalarea of deposition.

The sequence in UKA Cabawin No. I,where it is nearly 400 m thick, is probablyrepresentative for most of the area. Thelower part consists of dark grey pyritic car­bonaceous and silty shale, siltstone with car­bonaceous partings, and silicified lithic sand­stone. The upper part consists of interbeddedblue-grey calcareous siltstone and shale, andlithic sandstone.

The fauna consists mainly of brachiopodsand crinoids, and the environment of deposi­tion ranged from moderately deep marine(depth of water less than 100 m) to coastalswamps. The tuffaceous material in the rockmay have been derived from older volcanics,

or it may represent contemporaneous vol­camsm.

The shelly fossils, plants, and microfossilsall confirm the Permian age of the group.

Blackwater GroupThe Blackwater Group consists of 300 m

or less of coal measures. It overlaps theBack Creek Group on the west side of theTaroom Trough, where it rests directly onbasement rocks, by as much as 20 km (Fig.13 ). The present boundary of the group inthe west probably coincides roughly with thewestern limit of the depositional basin. Thegroup is not present to the east of the faultzone on the east side of the trough, and itsoriginal easterly extent is unknown. In thefar south, where the sequence consists ofinterbedded coal, shale, siltstone, sandstone,tuft, and conglomerate, the maximum thick­ness is less than 50 m. The tufts are mica­ceous and carbonaceous, and many of thecoaly beds contain some volcanic ash. Thesandstones range from lithic to quartzose.

The beds were deposited in swampy low­lands, and although they contain no marinemacrofossils, they do contain a Late Per­mian microflora (de Jersey and Evans inPSSA Publication 43, UKA Cabawin No. 1well completion report-see Table 1).

LOWER TRIASSIC BOWEN BASIN SEQUENCE

(Table 17)Tissot (1963) has pointed out that the

seismic and well data show that:(i) in the central part of the basin, theLower Triassic sequence is conformable onthe Upper Permian coal measures; (ii) onboth the eastern and western borders of thebasin north of 26°30'S, the Lower Triassicsequence is conformable with the coal meas­ures, both of which are truncated by theunconformably overlying Lower Jurassicsequence; and (iii) on both borders of thebasin south of 26° 30'S, the Lower Triassicsequence rests unconformably on the coalmeasures. The nearly horizontal LowerTriassic beds onlap against tilted coal meas­ures that were rising to form the presentstructural basin.

Thus (after Tissot, 1963) we can supposecontinuous subsidence and sedimentation inthe central part of the Triassic basin. In the

75

south both margins began to move, the west­ern by gentle folding and the eastern byfolding and faulting, in Late Permian toEarly Triassic time, when the basin began toassume its present shape. Later in the EarlyTriassic, sedimentation started to lap overthese border areas. In the north, on the otherhand, sedimentation was continuous even onthe present borders, and the folding andfaulting took place later.

In most of the basin a sequence of fluvialand lacustrine varicoloured mud, silt, andsand was laid down, but near the southerlyfault zone, and especially in the Moonie­Cabawin area, fluvial gravels predominated.The normal fades is assigned in this Bul­letin to the Rewan Group (Jensen, 1975),and the conglomerate fades to the CabawinFormation (Mack, 1963).

Rewan GroupThe Rewan Formation (Isbell, 1955) has

been upgraded to group status by Jensen(1975), who has divided the group into twoformations-the Sagittarius Sandstone over­lain by the Arcadia Formation-which havenot yet been widely identified in the sub­surface.

The type area of the Rewan Group(Isbell, 1955; Hill, 1957) is near Rewanhometsead in the Springsure Sheet area,where it is 500 m thick (Mollan et al.,1969). Its nature and relation to the Caba­win Formation have been investigated bydetailed petrological studies by Tissot(1963), Fehr (1965), and Bastian (1965a,c) .

In outcrop (Jensen, 1975), the Sagit­tarius Sandstone consists of interbeddedlithic sandstone, siltstone, and mudstone.The sandstone ranges from fine to coarse­grained, is calcareous in part, and containsscattered mud clasts and plant fragments.The siltstone and mudstone are green,brown, or grey, and in the subsurface aremottled in places. The contact with theunderlying coal measures of the BlackwaterGroup is taken at the top of the youngestcoal seam, and the same criterion is usedthroughout the basin in the subsurface.

The Arcadia Formation (Jensen, 1975)comprises all but the lowest 50 m of the

or it may represent contemporaneous vol­camsm.

The shelly fossils, plants, and microfossilsall confirm the Permian age of the group.

Blackwater GroupThe Blackwater Group consists of 300 m

or less of coal measures. It overlaps theBack Creek Group on the west side of theTaroom Trough, where it rests directly onbasement rocks, by as much as 20 km (Fig.13 ). The present boundary of the group inthe west probably coincides roughly with thewestern limit of the depositional basin. Thegroup is not present to the east of the faultzone on the east side of the trough, and itsoriginal easterly extent is unknown. In thefar south, where the sequence consists ofinterbedded coal, shale, siltstone, sandstone,tuft, and conglomerate, the maximum thick­ness is less than 50 m. The tufts are mica­ceous and carbonaceous, and many of thecoaly beds contain some volcanic ash. Thesandstones range from lithic to quartzose.

The beds were deposited in swampy low­lands, and although they contain no marinemacrofossils, they do contain a Late Per­mian microflora (de Jersey and Evans inPSSA Publication 43, UKA Cabawin No. 1well completion report-see Table 1).

LOWER TRIASSIC BOWEN BASIN SEQUENCE

(Table 17)Tissot (1963) has pointed out that the

seismic and well data show that:(i) in the central part of the basin, theLower Triassic sequence is conformable onthe Upper Permian coal measures; (ii) onboth the eastern and western borders of thebasin north of 26°30'S, the Lower Triassicsequence is conformable with the coal meas­ures, both of which are truncated by theunconformably overlying Lower Jurassicsequence; and (iii) on both borders of thebasin south of 26° 30'S, the Lower Triassicsequence rests unconformably on the coalmeasures. The nearly horizontal LowerTriassic beds onlap against tilted coal meas­ures that were rising to form the presentstructural basin.

Thus (after Tissot, 1963) we can supposecontinuous subsidence and sedimentation inthe central part of the Triassic basin. In the

75

south both margins began to move, the west­ern by gentle folding and the eastern byfolding and faulting, in Late Permian toEarly Triassic time, when the basin began toassume its present shape. Later in the EarlyTriassic, sedimentation started to lap overthese border areas. In the north, on the otherhand, sedimentation was continuous even onthe present borders, and the folding andfaulting took place later.

In most of the basin a sequence of fluvialand lacustrine varicoloured mud, silt, andsand was laid down, but near the southerlyfault zone, and especially in the Moonie­Cabawin area, fluvial gravels predominated.The normal fades is assigned in this Bul­letin to the Rewan Group (Jensen, 1975),and the conglomerate fades to the CabawinFormation (Mack, 1963).

Rewan GroupThe Rewan Formation (Isbell, 1955) has

been upgraded to group status by Jensen(1975), who has divided the group into twoformations-the Sagittarius Sandstone over­lain by the Arcadia Formation-which havenot yet been widely identified in the sub­surface.

The type area of the Rewan Group(Isbell, 1955; Hill, 1957) is near Rewanhometsead in the Springsure Sheet area,where it is 500 m thick (Mollan et al.,1969). Its nature and relation to the Caba­win Formation have been investigated bydetailed petrological studies by Tissot(1963), Fehr (1965), and Bastian (1965a,c) .

In outcrop (Jensen, 1975), the Sagit­tarius Sandstone consists of interbeddedlithic sandstone, siltstone, and mudstone.The sandstone ranges from fine to coarse­grained, is calcareous in part, and containsscattered mud clasts and plant fragments.The siltstone and mudstone are green,brown, or grey, and in the subsurface aremottled in places. The contact with theunderlying coal measures of the BlackwaterGroup is taken at the top of the youngestcoal seam, and the same criterion is usedthroughout the basin in the subsurface.

The Arcadia Formation (Jensen, 1975)comprises all but the lowest 50 m of the

TABLE 17. TRIASSIC STRATIGRAPHY, BOWEN AND IPSWICH-MORETON BASINS

Name(map symbol)

RaceviewFormation

(TRS)

UpperTriassic Aberdare

Conglomerate(TRS)

?Middle VolcanicsTriassic (TRS)

Middle MoolayemberTriasic 'Formation

(TRill)

MaximumThickness (m)

70

380

Drilled 260±;seismic, 750

1500

Lithology

Impermeable sand­stone, siltstone andshale, minor coal

Polymictic conglo­merate, grey, green, orred shale, minor coal

Interbedded gentlydipping acid lavas andtuffs; greenish, mas­sive, crystalline, sili­ceous, dense, hard

Siltstone, mudstone,lithic and lithic sub­labile sandstone; cal­careous in part

Fossils

Uppermost Trias­sic spores. Plantscomparable tothose 0 f IpswichCoal MeasUppermost Trias­sic spores

None

Plants, spores,acritarchs, ex-tremely rarefreshwater pele­cypods

Environment ofDeposition

Terrestrial: streams,swamps, lakes

Fluviatile: channeland overbank de­position

Terrestrial volcanics

Fluviatile channeland overbank de­position; deltaicgrading possibly in­to shallow marinein axis of TaroomTrough

Relations

Moreton Basin unit; conform­able on Aberdare Congl. Pinchesout to W against KumbarillaRidge

Basal Moreton Basin unit; un­conformable on older Triassicsequence. In this area confinedto deeper part of Cecil PlainsSyncline

Ipswich Basin unit; unconform­able on Palaeozoic sequence.Deeper part of Cecil PlainsSyncline. Probable equivalent ofNeara Volc

Bowen Basin unit; conformableon Clematis Gp in much ofbasin, but laps onto Permianand older rocks on W side

MainReferences

Staines (1964),de Jersey (1970a)

Staines (1964),de Jersey (1970a)

Mellins (1971)

Mollan et al.(1972), de Jersey& Hamilton(1967)

Clematis 300 Quartzose to sublabile Plants, sporesGroup sandstone, minor con-

Lower (TRe) glomerate, siltstone,to and shaleMiddle 'Wandoan 400 Quartzose to lithic Plants, sporesTriassic Formation' sandstone, conglo-

(TRW) merate, siltstone, shale

Fluviatile channeland overbank de­position

Fluviatile channeland overbank de­position; deltaicgrading possibly in­to shallow marinein axis of TaroomTrough

Bowen Basin unit; generallyconformable on Rewan Gp.Showgrounds Sst of Roma Shelfis upper part of Clematis GpSubsurface Bowen Basin unitequivalent to Clematis Gp andMoolayember Fm. Generallyconformable on Rewan Gp

Mollan et al.(1972), de Jersey(1968), Jensen(1975 )Union (1964), deJersey & Hamil­ton (1969)

Lower Rewan GroupTriassic (TRlr)

3500 Reddish brown andgreen mudstone, silt­stone, lithic to lithicsublabile sandstone,conglomerate

Rather rare plantdebris and spores

Terrestrial: fluvia­tile channel andoverbank deposition,soils. Possibly aeolianin part

Bowen Basin unit; conformableor disconformable on Permiansediments in much of basin, un­conformable around S margins.Union's subsurface 'CabawinFormation' in S

Mollan et al.(1972), de Jersey(1970b), Jensen(1975)

TABLE 17. TRIASSIC STRATIGRAPHY, BOWEN AND IPSWICH-MORETON BASINS

Name(map symbol)

RaceviewFormation

(TRS)

UpperTriassic Aberdare

Conglomerate(TRS)

?Middle VolcanicsTriassic (TRS)

Middle MoolayemberTriasic 'Formation

(TRill)

MaximumThickness (m)

70

380

Drilled 260±;seismic, 750

1500

Lithology

Impermeable sand­stone, siltstone andshale, minor coal

Polymictic conglo­merate, grey, green, orred shale, minor coal

Interbedded gentlydipping acid lavas andtuffs; greenish, mas­sive, crystalline, sili­ceous, dense, hard

Siltstone, mudstone,lithic and lithic sub­labile sandstone; cal­careous in part

Fossils

Uppermost Trias­sic spores. Plantscomparable tothose 0 f IpswichCoal MeasUppermost Trias­sic spores

None

Plants, spores,acritarchs, ex-tremely rarefreshwater pele­cypods

Environment ofDeposition

Terrestrial: streams,swamps, lakes

Fluviatile: channeland overbank de­position

Terrestrial volcanics

Fluviatile channeland overbank de­position; deltaicgrading possibly in­to shallow marinein axis of TaroomTrough

Relations

Moreton Basin unit; conform­able on Aberdare Congl. Pinchesout to W against KumbarillaRidge

Basal Moreton Basin unit; un­conformable on older Triassicsequence. In this area confinedto deeper part of Cecil PlainsSyncline

Ipswich Basin unit; unconform­able on Palaeozoic sequence.Deeper part of Cecil PlainsSyncline. Probable equivalent ofNeara Volc

Bowen Basin unit; conformableon Clematis Gp in much ofbasin, but laps onto Permianand older rocks on W side

MainReferences

Staines (1964),de Jersey (1970a)

Staines (1964),de Jersey (1970a)

Mellins (1971)

Mollan et al.(1972), de Jersey& Hamilton(1967)

Clematis 300 Quartzose to sublabile Plants, sporesGroup sandstone, minor con-

Lower (TRe) glomerate, siltstone,to and shaleMiddle 'Wandoan 400 Quartzose to lithic Plants, sporesTriassic Formation' sandstone, conglo-

(TRW) merate, siltstone, shale

Fluviatile channeland overbank de­position

Fluviatile channeland overbank de­position; deltaicgrading possibly in­to shallow marinein axis of TaroomTrough

Bowen Basin unit; generallyconformable on Rewan Gp.Showgrounds Sst of Roma Shelfis upper part of Clematis GpSubsurface Bowen Basin unitequivalent to Clematis Gp andMoolayember Fm. Generallyconformable on Rewan Gp

Mollan et al.(1972), de Jersey(1968), Jensen(1975 )Union (1964), deJersey & Hamil­ton (1969)

Lower Rewan GroupTriassic (TRlr)

3500 Reddish brown andgreen mudstone, silt­stone, lithic to lithicsublabile sandstone,conglomerate

Rather rare plantdebris and spores

Terrestrial: fluvia­tile channel andoverbank deposition,soils. Possibly aeolianin part

Bowen Basin unit; conformableor disconformable on Permiansediments in much of basin, un­conformable around S margins.Union's subsurface 'CabawinFormation' in S

Mollan et al.(1972), de Jersey(1970b), Jensen(1975)

type section of the Rewan Formation asmeasured by Mollan et al. (1969). TheArcadia Formation is characterized by thicksequences of red-brown mudstone, and isreadily eroded. Red-brown mudstone andsilty mudstone, with thin beds of green silt­stone and very fine sandstone, are inter­bedded with thick beds of fine to medium­grained cross-bedded green sandstone. Thesandstone is calcareous in places.

The thickness cropping out reaches amaximum of 3500 to 4000 m west of Theo­dore (Fig. 15). Jensen has shown that thebeds were laid down by a system of mean­dering and anastomosing channels, and thatthe red colour of the mudstone is due to thepresence of finely divided hematite derivedfrom red soils in the source area.

On the Roma Shelf, where the RewanGroup is generally less than 200 m thick,Fehr & Bastian (1963) and Bastian (1965a)have shown that sandstone and mudstonepredominate. The sandstone is mainly greenand lithic, and the mudstone red-brown andgreen.

Detailed petrological work by Fehr (seeTissot, 1963) has shown that deposition ofthe Rewan Group sequence began at differ­ent times, with different sediments, in differ­ent areas. Thus, in AAO Meeleebee No. I alower member (So), which seems to cor­relate with the lower part of the type sectionof the Cabawin Formation, is present. Thesequence consists of very thickly beddedconglomerate and sandstone, which containpebbles of tuff and some tuffaceous matrix.On most of the Roma Shelf, however, thefiner-grained sediments resting on the pre­Triassic rocks are presumed to be younger.They consist of fine-grained green sandstonegrading into green, grey, and brown silt­stone, and varicoloured mudstone.

In the subsurface on the eastern side ofthe basin, in the Miles-Taroom area, thegroup consists of a thick monotonoussequence of mudstone, siltstone, and sand­stone, containing a considerable proportionof tuffaceous debris. In UKA Wandoan No.I, for example (Union, 1965), the group is1379 m thick. The mlldstone and siltstoneare mottled green, red, and brown, with

77

streaks and laminae of macerated carbona­ceolls matter at some levels. The sandstoneis greenish white to green, lithic, and con­tains an abundant clay matrix. Conglomer­ate is generally rare in this area.

The palynological evidence outlined in thecompletion reports on the numerous petro­leum exploration wells in the Rewan Groupand the equivalent Cabawin Formationattests to the Early Triassic age of the group(see also de Jersey, 1970b).

Cabawin Formation

The Cabawin Formation was defined byMack (1963), with its type section between7640 and 9835 feet (2329-2998 m) in theUKA Cabawin No. I well. The sequenceconsists mainly of conglomeratic sandstoneand conglomerate, with some varicolouredmudstone. The conglomerate beds consist ofpebbles and cobbles of quartz, chert, quartz­ite, and tuff set in a clayey tuffaceous matrix.The mudstone is reddish brown, mustard­coloured, or grey, and grades into siltstone.

In the subsurface the distinctive conglo­meratic facies can be traced only as far northas UKA Davidson No. I and as far south asUKA Sussex Downs No. I. Thus the forma­tion is confined to the Taroom Trough,where it flanks the Moonie-Goondiwindifault system. It does not extend as far northas Miies, or as far south as Goondiwindi;nor does it occur west of the axis of thetrough (e.g. in UKA Kinkabilla No. I).

Thus the massive conglomerates can be re­lated to movements on the Moonie-Goondi­windi fault system in the southern part ofthe Taroom Trough; they were probablydeposited as fanglomerates near a faultscarp, and were mainly derived from Per­mian and Carboniferous volcanics on theupthrown eastern side of the fault system.To the west and north they interfinger withfiner-grained sediments of the Rewan Group,and to the south they were either not depo­sited or have been removed by erosion. Simi­lar conglomerates occur in the lower part ofthe Rewan Group in places, but they do notpredominate.

The maximum thickness of the CabawinFormation is probably about 1000 m nearMeandarra (Fig. 15). Part of the formation

type section of the Rewan Formation asmeasured by Mollan et al. (1969). TheArcadia Formation is characterized by thicksequences of red-brown mudstone, and isreadily eroded. Red-brown mudstone andsilty mudstone, with thin beds of green silt­stone and very fine sandstone, are inter­bedded with thick beds of fine to medium­grained cross-bedded green sandstone. Thesandstone is calcareous in places.

The thickness cropping out reaches amaximum of 3500 to 4000 m west of Theo­dore (Fig. 15). Jensen has shown that thebeds were laid down by a system of mean­dering and anastomosing channels, and thatthe red colour of the mudstone is due to thepresence of finely divided hematite derivedfrom red soils in the source area.

On the Roma Shelf, where the RewanGroup is generally less than 200 m thick,Fehr & Bastian (1963) and Bastian (1965a)have shown that sandstone and mudstonepredominate. The sandstone is mainly greenand lithic, and the mudstone red-brown andgreen.

Detailed petrological work by Fehr (seeTissot, 1963) has shown that deposition ofthe Rewan Group sequence began at differ­ent times, with different sediments, in differ­ent areas. Thus, in AAO Meeleebee No. I alower member (So), which seems to cor­relate with the lower part of the type sectionof the Cabawin Formation, is present. Thesequence consists of very thickly beddedconglomerate and sandstone, which containpebbles of tuff and some tuffaceous matrix.On most of the Roma Shelf, however, thefiner-grained sediments resting on the pre­Triassic rocks are presumed to be younger.They consist of fine-grained green sandstonegrading into green, grey, and brown silt­stone, and varicoloured mudstone.

In the subsurface on the eastern side ofthe basin, in the Miles-Taroom area, thegroup consists of a thick monotonoussequence of mudstone, siltstone, and sand­stone, containing a considerable proportionof tuffaceous debris. In UKA Wandoan No.I, for example (Union, 1965), the group is1379 m thick. The mlldstone and siltstoneare mottled green, red, and brown, with

77

streaks and laminae of macerated carbona­ceolls matter at some levels. The sandstoneis greenish white to green, lithic, and con­tains an abundant clay matrix. Conglomer­ate is generally rare in this area.

The palynological evidence outlined in thecompletion reports on the numerous petro­leum exploration wells in the Rewan Groupand the equivalent Cabawin Formationattests to the Early Triassic age of the group(see also de Jersey, 1970b).

Cabawin Formation

The Cabawin Formation was defined byMack (1963), with its type section between7640 and 9835 feet (2329-2998 m) in theUKA Cabawin No. I well. The sequenceconsists mainly of conglomeratic sandstoneand conglomerate, with some varicolouredmudstone. The conglomerate beds consist ofpebbles and cobbles of quartz, chert, quartz­ite, and tuff set in a clayey tuffaceous matrix.The mudstone is reddish brown, mustard­coloured, or grey, and grades into siltstone.

In the subsurface the distinctive conglo­meratic facies can be traced only as far northas UKA Davidson No. I and as far south asUKA Sussex Downs No. I. Thus the forma­tion is confined to the Taroom Trough,where it flanks the Moonie-Goondiwindifault system. It does not extend as far northas Miies, or as far south as Goondiwindi;nor does it occur west of the axis of thetrough (e.g. in UKA Kinkabilla No. I).

Thus the massive conglomerates can be re­lated to movements on the Moonie-Goondi­windi fault system in the southern part ofthe Taroom Trough; they were probablydeposited as fanglomerates near a faultscarp, and were mainly derived from Per­mian and Carboniferous volcanics on theupthrown eastern side of the fault system.To the west and north they interfinger withfiner-grained sediments of the Rewan Group,and to the south they were either not depo­sited or have been removed by erosion. Simi­lar conglomerates occur in the lower part ofthe Rewan Group in places, but they do notpredominate.

The maximum thickness of the CabawinFormation is probably about 1000 m nearMeandarra (Fig. 15). Part of the formation

78

may be older than the Rewan Group, al­though the pollens are indistinguishable fromthose in the Rewan Group.

MIDDLE TRIASSIC BOWEN BASIN SEQUENCE

In outcrop the Middle Triassic sequenceis represented by the Clematis Group andthe overlying Moolayember Formation(Table 17); the same units are recognizableon the Roma Shelf, although they are muchthinner. In most of the subsurface these sub­divisions are not easily recognizable, and theentire Middle Triassic sequence is hereassigned to the Wandoan Formation (seealso cross-sections on map).

Seismic and well data show that sedi­mentation and subsidence were continuousin the deepest part of the basin during theEarly and Middle Triassic (see also Tissot,1963). In a few areas along the northernmargin of the basin, such as on the Wan­doan axis on which the UKA Wandoan No.1 well lies, folding started in Middle Triassictime, with the result that the Middle Triassicbeds rest directly on the Upper Permian coalmeasures. In the western and southern partsof the basin the Middle Triassic beds lappedonto pre-Triassic rocks, but in the east theydo not appear to have transgressed beyondthe Burunga-Moonie-Goondiwindi zone offaulting.

In Middle Triassic time (Fig. 16) thebasin was a half-graben in which there wasrapid sinking and thick sedimentation in theeast. The maximum thickness of the succes­sion in the north, west of Theodore, is about2000 m, but it thins rapidly to the south toabout 300 m southwest of Wandoan. In adepression near Glenmorgan the sequence is600 m thick, but to the south the maximumthickness decreases steadily to about 200 mwest of Goondiwindi.

Clematis GroupThe Clematis Sandstone (Jensen, 1926)

was named after Clematis Creek in theExpedition Range, where it consists mainlyof quartzose sandstone with minor siltstonetowards the top. The unit has been upgradedby Jensen (1975) to group status, and nowcomprises the Glenidal Formation and Ex­pedition Sandstone.

The Glenidal Formation conformablyoverlies the Rewan Group, and consists ofmudstone, some of which is red, siltstone,and sandstone. The type section is in theCarnarvon Ranges (25°l1'S; l48'35'E).The lower boundary is taken at the changefrom labile sandstone to sublabile sandstone,which corresponds with a decrease in theamount of mudstone. The Expedition Sand­stone consists predominantly of quartzoseto sublabile sandstone, with some lenses ofgrey or red siltstone and muddy siltstone.The type section, which is about 145 mthick, is in the hills immediately east ofSerocold homestead in the Springsure Sheetarea (see Mollan et al., 1969, Sect. S29).The sandstone grades into pebbly sandstoneand conglomerate in places, and is cross­bedded.

In outcrop the Clematis Group thickensto the east from about 100 m on the Spring­sure Shelf west of the Denison Trough toseveral hundred metres in the ExpeditionRange and to about 800 m in the DawsonRange. A system of braided and meanderingchannels spread sand southward (Fig. 16),and in some areas, especially early in Cle­matis Group time, soils were developed.

The hydrocarbon-bearing ShowgroundsSandstone of the Roma Shelf was named byTraves & Thralls (1960), and has beenalluded to in many Mines AdministrationPty Ltd publications since. Swindon (1968)equated it with the upper part of the Clema­tis Sandstone. It is a white quartzose sand­stone that was derived from the quartz­veined Timbury Hills Formation and theRoma granite. It was deposited by streamseither unconformably on basement rocks orconformably on the Rewan Group. Traves( 1971) stated that it 'has medium porosity(14-19%) and high permeability (up to 4darcys). The sand is coarse-grained, sub­angular, with fair to good sorting.' Thethickness of the formation averages only5 m, but is over 15 m along the eastern sideof the Roma Shelf.

Moolayember FormationThe Moolayember Formation was first

named the Moolayember Shale by Reeves(1947) after Moolayember Creek in the

78

may be older than the Rewan Group, al­though the pollens are indistinguishable fromthose in the Rewan Group.

MIDDLE TRIASSIC BOWEN BASIN SEQUENCE

In outcrop the Middle Triassic sequenceis represented by the Clematis Group andthe overlying Moolayember Formation(Table 17); the same units are recognizableon the Roma Shelf, although they are muchthinner. In most of the subsurface these sub­divisions are not easily recognizable, and theentire Middle Triassic sequence is hereassigned to the Wandoan Formation (seealso cross-sections on map).

Seismic and well data show that sedi­mentation and subsidence were continuousin the deepest part of the basin during theEarly and Middle Triassic (see also Tissot,1963). In a few areas along the northernmargin of the basin, such as on the Wan­doan axis on which the UKA Wandoan No.1 well lies, folding started in Middle Triassictime, with the result that the Middle Triassicbeds rest directly on the Upper Permian coalmeasures. In the western and southern partsof the basin the Middle Triassic beds lappedonto pre-Triassic rocks, but in the east theydo not appear to have transgressed beyondthe Burunga-Moonie-Goondiwindi zone offaulting.

In Middle Triassic time (Fig. 16) thebasin was a half-graben in which there wasrapid sinking and thick sedimentation in theeast. The maximum thickness of the succes­sion in the north, west of Theodore, is about2000 m, but it thins rapidly to the south toabout 300 m southwest of Wandoan. In adepression near Glenmorgan the sequence is600 m thick, but to the south the maximumthickness decreases steadily to about 200 mwest of Goondiwindi.

Clematis GroupThe Clematis Sandstone (Jensen, 1926)

was named after Clematis Creek in theExpedition Range, where it consists mainlyof quartzose sandstone with minor siltstonetowards the top. The unit has been upgradedby Jensen (1975) to group status, and nowcomprises the Glenidal Formation and Ex­pedition Sandstone.

The Glenidal Formation conformablyoverlies the Rewan Group, and consists ofmudstone, some of which is red, siltstone,and sandstone. The type section is in theCarnarvon Ranges (25°l1'S; l48'35'E).The lower boundary is taken at the changefrom labile sandstone to sublabile sandstone,which corresponds with a decrease in theamount of mudstone. The Expedition Sand­stone consists predominantly of quartzoseto sublabile sandstone, with some lenses ofgrey or red siltstone and muddy siltstone.The type section, which is about 145 mthick, is in the hills immediately east ofSerocold homestead in the Springsure Sheetarea (see Mollan et al., 1969, Sect. S29).The sandstone grades into pebbly sandstoneand conglomerate in places, and is cross­bedded.

In outcrop the Clematis Group thickensto the east from about 100 m on the Spring­sure Shelf west of the Denison Trough toseveral hundred metres in the ExpeditionRange and to about 800 m in the DawsonRange. A system of braided and meanderingchannels spread sand southward (Fig. 16),and in some areas, especially early in Cle­matis Group time, soils were developed.

The hydrocarbon-bearing ShowgroundsSandstone of the Roma Shelf was named byTraves & Thralls (1960), and has beenalluded to in many Mines AdministrationPty Ltd publications since. Swindon (1968)equated it with the upper part of the Clema­tis Sandstone. It is a white quartzose sand­stone that was derived from the quartz­veined Timbury Hills Formation and theRoma granite. It was deposited by streamseither unconformably on basement rocks orconformably on the Rewan Group. Traves( 1971) stated that it 'has medium porosity(14-19%) and high permeability (up to 4darcys). The sand is coarse-grained, sub­angular, with fair to good sorting.' Thethickness of the formation averages only5 m, but is over 15 m along the eastern sideof the Roma Shelf.

Moolayember FormationThe Moolayember Formation was first

named the Moolayember Shale by Reeves(1947) after Moolayember Creek in the

Carnarvon Ranges. The name was amendedto Moolayember Formation by Mollan et al.(1972), who described the type section. Inthe type area the formation consists ofgreen-brown lithic sandstone interbeddedwith green-brown mudstone. In the Expedi­tion Range farther east, mudstone predomin­ates, and there is also a little conglomerate.In the Dawson Range in the east thesequence consists mainly of mudstone inter­bedded with conglomerate, tuff, and sand­stone.

The formation thickens from about 300 mon the Springsure Shelf to over 1500 m inthe middle of the Taroom Trough. On plantevidence its age is Triassic or Early Jurassic(M. White, appendix 3 in Mollan et al.,1972). The spores are of Middle Triassicage (de Jersey & Hamilton, 1967).

Mollan et al. (1972) stated that 'Theabundance of plant material and lack ofmarine fossils suggest that the MoolayemberFormation is mainly terrestrial. The abund­ance of conglomerate in the east and thepresence of trough cross-bedded sandstonethroughout the sequence point to a fluvialenvironment, although it is not impossiblethat some of the deposition took place inlakes. There are some indications, especiallyin the east, of contemporaneous vulcanism,and certainly the sediments in the east werelargely derived from a volcanic terrain.'

On the Roma Shelf the formation consistsof grey to brown carbonaceous shale, silt­stone, and grey lithic sandstone. It is gener­ally less than 100 m thick, but reaches300 m on the eastern edge of the shelf. Itoverlaps the Showgrounds Sandstone to thewest, where it rests directly on basementrocks.

Wandoan FormationThe section from 3530 to 4817 feet

(1076-1468 m) in the UKA Wandoan No 1well was defined as the type section of theWandoan Formation (Union, 1964). De­tailed petrological studies of outcrops, andof samples from UKA Wandoan No. 1and other wells by Fehr & Bastian (1963),Fehr (1965), Bastian (1965a), and Bastian& Arman (1965), have shown that theformation is equivalent to the Clematis

79

Group and Moolayember Formation. Thisinterpretation is supported by various palyno­logical studies (e.g. Evans, appendix 2 inUnion, 1965; de Jersey & Hamilton, 1969).In this Bulletin the term Wandoan Forma­tion is used for the Middle Triassic sequencebelow the Surat Basin, except on the RomaShelf.

In UKA Wandoan No. I the formationconsists of sandstone, carbonaceous shale,and siltstone. Bastian & Arman ( 1965)have described a twofold subdivision in thiswell:

(a) Between 1310 and 1468 m thesequence mainly consists of fine to medium­grained clayey sublabile to labile sandstonein which the grains are angular to subangularand of moderate sphericity. In most of thesandstones the quartz content ranges from50 to 80 percent, and there is up to 10 per­cent feldspar, 15 percent chert, and 15 per­cent mica and chlorite; tourmaline and zir­con are common accessories. The sandstonegrades into conglomerate in the upper 12 m,and brown to grey siltstone and shale arecommon below 1322 m (Union, 1965).

(b) Between 1076 and 1310 m the unitconsists of fine sandstone, siltstone, andshale, with siltstone and shale predominanttoward the base. The sandstones contain 10to 40 percent quartz, 10 to 15 percent feld­spar, up to 10 percent chert, 5 to 15 percentmica (predominantly biotite), and 15 to 30percent matrix. Calcite is rather rare in con­trast to the unit in outcrop. The upper partof this unit contains less quartz and morefeldspar than the lower part, and chamositepellets are fairly common in the upper part.

The white chert clasts in the formationappear to be devitrified tuff and were pre­sumably derived from the Permian and base­ment rocks east of the major fault zone.

Fehr (1965) recognized several wide­spread lithological subunits which 'are signi­ficantly thinner in marginal parts of thebasin' in the Surat Basin, and were definedby Fehr & Bastian (1963):

Subunit T5, the youngest subunit, is foundonly in the middle of the basin, and con­sists of two sandstone sequences separatedby a shaly sequence. It is 109 m thick inUKA Coomrith No. 1.

Carnarvon Ranges. The name was amendedto Moolayember Formation by Mollan et al.(1972), who described the type section. Inthe type area the formation consists ofgreen-brown lithic sandstone interbeddedwith green-brown mudstone. In the Expedi­tion Range farther east, mudstone predomin­ates, and there is also a little conglomerate.In the Dawson Range in the east thesequence consists mainly of mudstone inter­bedded with conglomerate, tuff, and sand­stone.

The formation thickens from about 300 mon the Springsure Shelf to over 1500 m inthe middle of the Taroom Trough. On plantevidence its age is Triassic or Early Jurassic(M. White, appendix 3 in Mollan et al.,1972). The spores are of Middle Triassicage (de Jersey & Hamilton, 1967).

Mollan et al. (1972) stated that 'Theabundance of plant material and lack ofmarine fossils suggest that the MoolayemberFormation is mainly terrestrial. The abund­ance of conglomerate in the east and thepresence of trough cross-bedded sandstonethroughout the sequence point to a fluvialenvironment, although it is not impossiblethat some of the deposition took place inlakes. There are some indications, especiallyin the east, of contemporaneous vulcanism,and certainly the sediments in the east werelargely derived from a volcanic terrain.'

On the Roma Shelf the formation consistsof grey to brown carbonaceous shale, silt­stone, and grey lithic sandstone. It is gener­ally less than 100 m thick, but reaches300 m on the eastern edge of the shelf. Itoverlaps the Showgrounds Sandstone to thewest, where it rests directly on basementrocks.

Wandoan FormationThe section from 3530 to 4817 feet

(1076-1468 m) in the UKA Wandoan No 1well was defined as the type section of theWandoan Formation (Union, 1964). De­tailed petrological studies of outcrops, andof samples from UKA Wandoan No. 1and other wells by Fehr & Bastian (1963),Fehr (1965), Bastian (1965a), and Bastian& Arman (1965), have shown that theformation is equivalent to the Clematis

79

Group and Moolayember Formation. Thisinterpretation is supported by various palyno­logical studies (e.g. Evans, appendix 2 inUnion, 1965; de Jersey & Hamilton, 1969).In this Bulletin the term Wandoan Forma­tion is used for the Middle Triassic sequencebelow the Surat Basin, except on the RomaShelf.

In UKA Wandoan No. I the formationconsists of sandstone, carbonaceous shale,and siltstone. Bastian & Arman ( 1965)have described a twofold subdivision in thiswell:

(a) Between 1310 and 1468 m thesequence mainly consists of fine to medium­grained clayey sublabile to labile sandstonein which the grains are angular to subangularand of moderate sphericity. In most of thesandstones the quartz content ranges from50 to 80 percent, and there is up to 10 per­cent feldspar, 15 percent chert, and 15 per­cent mica and chlorite; tourmaline and zir­con are common accessories. The sandstonegrades into conglomerate in the upper 12 m,and brown to grey siltstone and shale arecommon below 1322 m (Union, 1965).

(b) Between 1076 and 1310 m the unitconsists of fine sandstone, siltstone, andshale, with siltstone and shale predominanttoward the base. The sandstones contain 10to 40 percent quartz, 10 to 15 percent feld­spar, up to 10 percent chert, 5 to 15 percentmica (predominantly biotite), and 15 to 30percent matrix. Calcite is rather rare in con­trast to the unit in outcrop. The upper partof this unit contains less quartz and morefeldspar than the lower part, and chamositepellets are fairly common in the upper part.

The white chert clasts in the formationappear to be devitrified tuff and were pre­sumably derived from the Permian and base­ment rocks east of the major fault zone.

Fehr (1965) recognized several wide­spread lithological subunits which 'are signi­ficantly thinner in marginal parts of thebasin' in the Surat Basin, and were definedby Fehr & Bastian (1963):

Subunit T5, the youngest subunit, is foundonly in the middle of the basin, and con­sists of two sandstone sequences separatedby a shaly sequence. It is 109 m thick inUKA Coomrith No. 1.

80

Subunit T4 consists of alternating darkgrey shale and thin sandstone, and is upto 100 m thick.Subunit T3 consists of a lower porousgrey sandstone part and an upper tightershaly-silty-sandy part; it is up to 80 mthick.Subunit T2 consists of a lower part of veryfine to fine quartz sandstone and an uppermore shaly and tuffaceous part; it is up to60 m thick.Subunit T1, the lowest subunit, is com­posed of a lower sandy part and a veryconsistent shaly upper part; it is up to 100m thick.Fehr (1965) equated the lower sandy part

of subunit T1 with the Showgrounds Sand­stone; the upper shaly part, and the remain­ing T units would then equate with theMoolayember Formation, the ShowgroundsSandstone being regarded as the upper partof the Clematis Group. Fehr's upper shalypart of subunit T1 was named the SnakeCreek Mudstone Member of the Moolayem­ber Formation by Rogetoorn (1970), whostates that it is a widespread marker horizonin the southwestern and south-central partsof the Bowen Basin.

From the studies of Fehr & Bastian(1963) and Fehr (1965) it is apparent thatmost of the Wandoan Formation can becorrelated with the Moolayember Formation,with generally less than 100 m of thesequence correlating with the Clematis Sand­stone. Fehr (1965) considers that most ofthe sequence was laid down in fresh water,with local marine incursions in subunit T4.Subsidence was renewed during deposition ofsubunit T4, when polygenetic feldspathicand tuffaceous sands were laid down.

TRIASSIC AND JURASSIC ROCKS CONFINEDTO IpSWICH-MoRETON BASIN (Table 17)

Regional settingA Triassic sequence is present in the sub­

surface in the Cecil Plains Syncline (seecross-section EF on map), which lies east ofthe Kumbarilla Ridge and is an embaymentof the Ipswich-Moreton Basin. In this areathe Upper Triassic Raceview Formation(Staines, 1964) generally rests directiy on

the pre-Triassic basement rocks, but in asmall area east of Cecil Plains townshipthere is a depression containing faulted sedi­ments of the Upper Triassic Aberdare Con­glomerate (see Staines, 1964) and volcanicsthat may be equivalents of the Middle Trias­sic Neara Volcanics (Mellins, 1971). TheTriassic sequences penetrated were 380 mthick in Phillips Cecil Plains No. 1 and 257m thick in the A.P. Rorrane No. 1 well;neither of the wells reached basement. Seis­mic data (Mellins, 1971) suggest that morethan 900 m of Triassic rocks occurs in themiddle of the Cecil Plains Syncline. TheTriassic sequence is overlain by up to 600m of Lower Jurassic sediments-the Reli­don and Marburg Sandstones- which inter­tongue with Surat Basin formations in thevicinity of the Kumbarilla Ridge (see Table18 for correlations). These are overlain bythe Walloon Coal Measures, which are com­mon to the Ipswich-Moreton and SuratBasins, and are treated with the latter.

Triassic volcanicsThe oldest Triassic rocks yet penetrated in

the Cecil Plains syncline are the volcanics inA.P. Rorrane No. 1 (Mellins, 1971), whichare regarded as probable equivalents of theNeara Volcanics of the Esk Rift. They con­sist of a series of interbedded relatively flat­lying acid lavas and tuffs, which are greenish,massive, crystalline, siliceous, dense, andhard. The thickness penetrated in A.P. Ror­rane No. 1 was 257 m (3518-4362 ft), butseismic data (Mellins, 1971) suggest that inthe Rorrane area there is over 750 m ofTriassic volcanics resting unconformably onthe Permo-Carboniferous basement.

If these volcanics are equivalent to theNeara Volcanics, then they are older thanthe Ipswich Coal Measures and are ofMiddle Triassic age.

A berdare ConglomerateThe Aberdare Conglomerate is named

after Aberdare Colliery in the Ipswich Sheetarea (Staines, 1964), where it consistsmainly of polymictic cobble and pebble con­glomerates, sandstone, siltstone, and thinbeds of carbonaceous shale. Beds of ferru­ginous shale are a distinctive feature in thetype area.

80

Subunit T4 consists of alternating darkgrey shale and thin sandstone, and is upto 100 m thick.Subunit T3 consists of a lower porousgrey sandstone part and an upper tightershaly-silty-sandy part; it is up to 80 mthick.Subunit T2 consists of a lower part of veryfine to fine quartz sandstone and an uppermore shaly and tuffaceous part; it is up to60 m thick.Subunit T1, the lowest subunit, is com­posed of a lower sandy part and a veryconsistent shaly upper part; it is up to 100m thick.Fehr (1965) equated the lower sandy part

of subunit T1 with the Showgrounds Sand­stone; the upper shaly part, and the remain­ing T units would then equate with theMoolayember Formation, the ShowgroundsSandstone being regarded as the upper partof the Clematis Group. Fehr's upper shalypart of subunit T1 was named the SnakeCreek Mudstone Member of the Moolayem­ber Formation by Rogetoorn (1970), whostates that it is a widespread marker horizonin the southwestern and south-central partsof the Bowen Basin.

From the studies of Fehr & Bastian(1963) and Fehr (1965) it is apparent thatmost of the Wandoan Formation can becorrelated with the Moolayember Formation,with generally less than 100 m of thesequence correlating with the Clematis Sand­stone. Fehr (1965) considers that most ofthe sequence was laid down in fresh water,with local marine incursions in subunit T4.Subsidence was renewed during deposition ofsubunit T4, when polygenetic feldspathicand tuffaceous sands were laid down.

TRIASSIC AND JURASSIC ROCKS CONFINEDTO IpSWICH-MoRETON BASIN (Table 17)

Regional settingA Triassic sequence is present in the sub­

surface in the Cecil Plains Syncline (seecross-section EF on map), which lies east ofthe Kumbarilla Ridge and is an embaymentof the Ipswich-Moreton Basin. In this areathe Upper Triassic Raceview Formation(Staines, 1964) generally rests directiy on

the pre-Triassic basement rocks, but in asmall area east of Cecil Plains townshipthere is a depression containing faulted sedi­ments of the Upper Triassic Aberdare Con­glomerate (see Staines, 1964) and volcanicsthat may be equivalents of the Middle Trias­sic Neara Volcanics (Mellins, 1971). TheTriassic sequences penetrated were 380 mthick in Phillips Cecil Plains No. 1 and 257m thick in the A.P. Rorrane No. 1 well;neither of the wells reached basement. Seis­mic data (Mellins, 1971) suggest that morethan 900 m of Triassic rocks occurs in themiddle of the Cecil Plains Syncline. TheTriassic sequence is overlain by up to 600m of Lower Jurassic sediments-the Reli­don and Marburg Sandstones- which inter­tongue with Surat Basin formations in thevicinity of the Kumbarilla Ridge (see Table18 for correlations). These are overlain bythe Walloon Coal Measures, which are com­mon to the Ipswich-Moreton and SuratBasins, and are treated with the latter.

Triassic volcanicsThe oldest Triassic rocks yet penetrated in

the Cecil Plains syncline are the volcanics inA.P. Rorrane No. 1 (Mellins, 1971), whichare regarded as probable equivalents of theNeara Volcanics of the Esk Rift. They con­sist of a series of interbedded relatively flat­lying acid lavas and tuffs, which are greenish,massive, crystalline, siliceous, dense, andhard. The thickness penetrated in A.P. Ror­rane No. 1 was 257 m (3518-4362 ft), butseismic data (Mellins, 1971) suggest that inthe Rorrane area there is over 750 m ofTriassic volcanics resting unconformably onthe Permo-Carboniferous basement.

If these volcanics are equivalent to theNeara Volcanics, then they are older thanthe Ipswich Coal Measures and are ofMiddle Triassic age.

A berdare ConglomerateThe Aberdare Conglomerate is named

after Aberdare Colliery in the Ipswich Sheetarea (Staines, 1964), where it consistsmainly of polymictic cobble and pebble con­glomerates, sandstone, siltstone, and thinbeds of carbonaceous shale. Beds of ferru­ginous shale are a distinctive feature in thetype area.

TABLE 18. JURASSIC-CRETACEOUS NOMENCLATURE IN SURAT AND ADJACENT BASINS

Sural Basin FormalEromanga Basin Nomenclature (Surat Roma Area Sural Basin Roma Area Moreton Basin

Formal Nomenclature Rama area) (Day. 1964) (Whitehouse, 1954) (Reeves, 1947) (GSQ nomenclature)

Winton Formation

Cl, Mackunda FormationGriman" Allaru Mudstone2 ?-Creek--?--?-

0 Toolebuc Limestone Formationl':l~

Wallumbilla Surat Siltstone0 CoreenaCl.. Formation Member Coreenac Member Wallumbilla~l:<: Doncaster Doncaster Formation

Member Member Roma Formation Rama Formation Rolling Downs

MinmiFormation

MemberCadna-owie Nullawurt TransitionFormation Bungil Formtaion

Sst Member Transition StageBeds

Kingull Blythesdale

Member Formation Blythesdale

Mooga Sandstone Mooga Mooga Group Mooga SandstoneSSI Member Sandstone

Hooray OralIo Formation Orallo Formation Fossil Wood Fossil Wood StageSandstone Beds

Gubberamunda Gubberamunda Gubberamunda GubberamundaSandstone Sandstone Sandstone Sandstone

Cl, Westbourne Formation WestbourneCl,

" Formation :>2 20 Adori Sandstone Springbok 0 Injune WaUoon Lower... Sandstone ~ Walloon~ Creek CoalU WaUoon Coal 5 Coal -u-u-u-u-u-u-u-u-u-u-u-u-u

" Birkhead Measures " Beds Measures Measures WaUoon Coalc c Measures" Formation ":s IEurombah :sFormation

Marburg?--?--?-_?~

Hutton Sandstone Hullon Sandstone HuttOD SandstoneFormation

IBoxvalc "Marburg

Evergreen Formation Sandstone Boxvale Sandstones ego Boxvale Sandstone FormationCl,

Evergreen Member " 0 "'O~

Formation ;0 2Evergreen Shales a:l Shale 0

Precipice Sandstone Precipice Sandstone Precipice Bundamba Sandstone Helidon """Sandstone Sandstone S-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u_u_u_u_u-U-\ "-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-U-\l-U-U '0

"Raceview "Formation a:l

AberdareConglomerate

TABLE 18. JURASSIC-CRETACEOUS NOMENCLATURE IN SURAT AND ADJACENT BASINS

Sural Basin FormalEromanga Basin Nomenclature (Surat Roma Area Sural Basin Roma Area Moreton Basin

Formal Nomenclature Rama area) (Day. 1964) (Whitehouse, 1954) (Reeves, 1947) (GSQ nomenclature)

Winton Formation

Cl, Mackunda FormationGriman" Allaru Mudstone2 ?-Creek--?--?-

0 Toolebuc Limestone Formationl':l~

Wallumbilla Surat Siltstone0 CoreenaCl.. Formation Member Coreenac Member Wallumbilla~l:<: Doncaster Doncaster Formation

Member Member Roma Formation Rama Formation Rolling Downs

MinmiFormation

MemberCadna-owie Nullawurt TransitionFormation Bungil Formtaion

Sst Member Transition StageBeds

Kingull Blythesdale

Member Formation Blythesdale

Mooga Sandstone Mooga Mooga Group Mooga SandstoneSSI Member Sandstone

Hooray OralIo Formation Orallo Formation Fossil Wood Fossil Wood StageSandstone Beds

Gubberamunda Gubberamunda Gubberamunda GubberamundaSandstone Sandstone Sandstone Sandstone

Cl, Westbourne Formation WestbourneCl,

" Formation :>2 20 Adori Sandstone Springbok 0 Injune WaUoon Lower... Sandstone ~ Walloon~ Creek CoalU WaUoon Coal 5 Coal -u-u-u-u-u-u-u-u-u-u-u-u-u

" Birkhead Measures " Beds Measures Measures WaUoon Coalc c Measures" Formation ":s IEurombah :sFormation

Marburg?--?--?-_?~

Hutton Sandstone Hullon Sandstone HuttOD SandstoneFormation

IBoxvalc "Marburg

Evergreen Formation Sandstone Boxvale Sandstones ego Boxvale Sandstone FormationCl,

Evergreen Member " 0 "'O~

Formation ;0 2Evergreen Shales a:l Shale 0

Precipice Sandstone Precipice Sandstone Precipice Bundamba Sandstone Helidon """Sandstone Sandstone S-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u_u_u_u_u-U-\ "-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-u-U-\l-U-U '0

"Raceview "Formation a:l

AberdareConglomerate

82

The Triassic sequence in the Phillips CecilPlains No. 1 well was subdivided by Hoge­toorn (appendix 1 in Meyers, 1970) into49 m (4090-4252 ft) of Raceview Forma­tion overlying 380 m (4252-5501 ft) of pos­sible Ipswich Coal Measures. The lowersequence was regarded by Mellins (1971) asprobable Aberdare Conglomerate, and thisinterpretation is preferred here.

The Aberdare Conglomerate, which inthis area has so far been penetrated only inCecil Plains No. 1, consists mainly of con­glomerate with some shale. The conglo­merate contains pebbles of shale, siltstone,sandstone, quartz, and quartzite. The shaleis predominantly grey or green, but below1590 m reddish hematitic shale is alsopresent. Minor thin bands of coal are presentin places.

Seismic and other evidence (Mellins,1971) show that the formation is at leastpartly bounded by faults in this area, andthat it extends only a few kilometres in anydirection from Phillips Cecil Plains No. 1,except perhaps to the east. It probably restsdisconformably on the Triassic volcanics atdepth, as there is considerable time-breakbetween the two units if the preferred agerelations are correct. Its maximum thicknessin the Cecil Plains Syncline may be as muchas 1000 m.

The spores obtained from cores in thePhillips Cecil Plains well (de Jersey, Paten,& Hamilton, 1964) suggest an uppermostTriassic age, which makes it unlikely thatthis sequence equates with the Middle Trias­sic Ipswich Coal Measures.

Raceview FormationThe Raceview Formation (Staines, 1964)

is named after Raceview in the IpswichSheet area, where it consists of interbeddedsandstone, siltstone, shale (some carbon­aceous ), and a few thin seams of coal.

East of the Kumbarilla Ridge, a sequenceof relatively impermeable sandstone, silt­stone, and shale, which is commonly foundbelow the Helidon Sandstone, containsspore assemblages that are transitionalbetween typical Triassic and typical Juras­sic assemblages. Recent lithological correla­tion (Hogetoorn, in Meyers, 1970), and in-

creasing knowledge of the spore assemblagein the type area, has led various workers(e.g. Mellins, 1971) to call this sequence theRaceview Formation.

The Raceview Formation pinches outagainst the Kumbarilla Ridge in the west,and the Texas High in the south. It generallyoverlies the Permo-Carboniferous basementrocks unconformably, but in the central partof the Cecil Plains Syncline it rests con­formably on the Aberdare Conglomerate, ordisconformably on Triassic volcanics. It isapparently unaffected by the faulting whichhas displaced the underlying Triassicsequences.

The formation was deposited in still water,perhaps in lakes and backswamps. Its thick­ness reaches 67 m in ARO 20 (Dalby) and49 m in Phillips Cecil Plains No. 1. Sporedata suggest a Late Triassic, probablyuppermost Triassic, age (de Jersey, 1970a).

Helidon SandstoneIn the Moreton Basin the Helidon Sand­

stone is the equivalent of the Precipice Sand­stone, and is included within it in the iso­pach maps (e.g. Figs 19, 20). The namesHelidon Series and Helidon Sandstone wereused by Dunstan (1915 ) and Richards( 1918) in their descriptions of the buildingstones near Helidon, east of Toowoomba.McTaggart (1963) mapped and defined theformation in the type area. The HelidonSandstone is confined to the Moreton Basin,and crops out as far west as White Mountain(15 km north-northeast of Helidon) and asfar east as Lowood.

Near Helidon it consists of 250 m ofmedium to very thickly bedded cross-beddedwhite feldspathic sublabile sandstone, andlesser siltstone. The sandstone weathersbrown, and contains yellowish clayey rockfragments and considerable clay matrix.McTaggart (1963) reported the presence ofa persistent basal conglomerate, and notedthat the sandstone becomes finer-grained,more massive, and paler upwards.

The formation is present in the sub­surface east of the Kumbarilla Ridge andnorth of Millmerran, where the name Heli­don Sandstone is preferable to the namePrecipice Sandstone commonly used by oil

82

The Triassic sequence in the Phillips CecilPlains No. 1 well was subdivided by Hoge­toorn (appendix 1 in Meyers, 1970) into49 m (4090-4252 ft) of Raceview Forma­tion overlying 380 m (4252-5501 ft) of pos­sible Ipswich Coal Measures. The lowersequence was regarded by Mellins (1971) asprobable Aberdare Conglomerate, and thisinterpretation is preferred here.

The Aberdare Conglomerate, which inthis area has so far been penetrated only inCecil Plains No. 1, consists mainly of con­glomerate with some shale. The conglo­merate contains pebbles of shale, siltstone,sandstone, quartz, and quartzite. The shaleis predominantly grey or green, but below1590 m reddish hematitic shale is alsopresent. Minor thin bands of coal are presentin places.

Seismic and other evidence (Mellins,1971) show that the formation is at leastpartly bounded by faults in this area, andthat it extends only a few kilometres in anydirection from Phillips Cecil Plains No. 1,except perhaps to the east. It probably restsdisconformably on the Triassic volcanics atdepth, as there is considerable time-breakbetween the two units if the preferred agerelations are correct. Its maximum thicknessin the Cecil Plains Syncline may be as muchas 1000 m.

The spores obtained from cores in thePhillips Cecil Plains well (de Jersey, Paten,& Hamilton, 1964) suggest an uppermostTriassic age, which makes it unlikely thatthis sequence equates with the Middle Trias­sic Ipswich Coal Measures.

Raceview FormationThe Raceview Formation (Staines, 1964)

is named after Raceview in the IpswichSheet area, where it consists of interbeddedsandstone, siltstone, shale (some carbon­aceous ), and a few thin seams of coal.

East of the Kumbarilla Ridge, a sequenceof relatively impermeable sandstone, silt­stone, and shale, which is commonly foundbelow the Helidon Sandstone, containsspore assemblages that are transitionalbetween typical Triassic and typical Juras­sic assemblages. Recent lithological correla­tion (Hogetoorn, in Meyers, 1970), and in-

creasing knowledge of the spore assemblagein the type area, has led various workers(e.g. Mellins, 1971) to call this sequence theRaceview Formation.

The Raceview Formation pinches outagainst the Kumbarilla Ridge in the west,and the Texas High in the south. It generallyoverlies the Permo-Carboniferous basementrocks unconformably, but in the central partof the Cecil Plains Syncline it rests con­formably on the Aberdare Conglomerate, ordisconformably on Triassic volcanics. It isapparently unaffected by the faulting whichhas displaced the underlying Triassicsequences.

The formation was deposited in still water,perhaps in lakes and backswamps. Its thick­ness reaches 67 m in ARO 20 (Dalby) and49 m in Phillips Cecil Plains No. 1. Sporedata suggest a Late Triassic, probablyuppermost Triassic, age (de Jersey, 1970a).

Helidon SandstoneIn the Moreton Basin the Helidon Sand­

stone is the equivalent of the Precipice Sand­stone, and is included within it in the iso­pach maps (e.g. Figs 19, 20). The namesHelidon Series and Helidon Sandstone wereused by Dunstan (1915 ) and Richards( 1918) in their descriptions of the buildingstones near Helidon, east of Toowoomba.McTaggart (1963) mapped and defined theformation in the type area. The HelidonSandstone is confined to the Moreton Basin,and crops out as far west as White Mountain(15 km north-northeast of Helidon) and asfar east as Lowood.

Near Helidon it consists of 250 m ofmedium to very thickly bedded cross-beddedwhite feldspathic sublabile sandstone, andlesser siltstone. The sandstone weathersbrown, and contains yellowish clayey rockfragments and considerable clay matrix.McTaggart (1963) reported the presence ofa persistent basal conglomerate, and notedthat the sandstone becomes finer-grained,more massive, and paler upwards.

The formation is present in the sub­surface east of the Kumbarilla Ridge andnorth of Millmerran, where the name Heli­don Sandstone is preferable to the namePrecipice Sandstone commonly used by oil

exploration companies. Meyers (1970) hassuggested that the lower parts of the HelidonSandstone (most of Meyers' 'Lower Preci­pice') and Precipice Sandstone do not linkup across the Kumbarilla Ridge, and thatthe upper parts join only north of Kum­barilla.

According to Meyers (1970), who madea detailed study of well data, the formationis divisible into a lower shaly part, a middlesandstone part, and an upper sandstone­shale part. The lower shaly sequence is in­terpreted by Hogetoorn (in Meyers, 1970),and the author, as Raceview Formation. Thisinterpretation agrees with the spore evidence(e.g. de Jersey et aI., 1964) and means thatdeposition of the Helidon Sandstone beganwith sand, as in the type area.

Thus there is a lower sandstone sequenceand an upper sandstone-shale sequence inthis area. The lower sequence consists (seeMeyers, 1970) largely of porous coarse­grained quartzose to sublabile sandstone,with a few grey shaly interbeds. The sand­stone contains subangular quartz grains andsome quartz pebbles, and generally has asiliceous cement and a clay matrix. Theupper sequence consists of sandstone andshale in roughly equal proportions. Thesandstone is sublabile, light grey, andgenerally fine to medium-grained; the dastsconsist of sub-rounded quartz, minor lithicgrains and feldspar, and rare red garnet. Therock has a clay matrix and it is generallynon-porous, and is characterized (as in thetype area) by the presence of numerousorange to yellow weathered grains. The grey­ish shaly beds contain 'black oolites' in Phil­lips Wilkie No. I and Cecil Plains No. I.

The Helidon Sandstone rests disconform­ably on the Raceview Formation in muchof the area described in this Bulletin, andunconformably overlies the Permo-Carboni­ferous basement rocks on the KumbarillaRidge. To the west it gives way to the morequartzose Precipice Sandstone, and to theeast to the Ripley Road Sandstone at theWest Ipswich Disturbance.

The sequence is thickest in the CecilPlains Syncline, where 146 m is recordedin the Phillips Cecil Plains No. I well.

83

Meyers (1970) has suggested that the mainsource area was to the cast, and that it con­sisted of metamorphic and possibly igneousrocks. The beds were laid down mainly bystreams, and consist of point-bar and chan­nel sands grading up into overbank deposits.The presence of oolites high in the sequencesuggests shallow-marine incursions.

The miospore assemblages (de Jersey,1971) indicate that the Helidon Sandstoneis of Jurassic age, whereas the apparentlylaterally continuous Ripley Road Sandstoneis mainly Rhaetic (uppermost Triassic) age.Thus deposition of the Ripley Road Sand­stone in the east began before the Helidonand Precipice Sandstone were laid down inthe west.

Marburg SandstoneThe Marburg Sandstone has been studied

by numerous authors, many of whom pre­ferred the name Marburg Formation; thenomenclatural problem has yet to be re­solved.

Reid (1921) subdivided the WalloonCoal measures into the Marburg and Rose­wood Stages. In the type area near Marburgthe formation consists of torrentially cross­bedded calcareous sandstone with someshale, silty sandstone, grit, and conglomer­ate. Swindon (1960) used the term MarburgSandstone in his description of the sandstonein the type area. McTaggart (1963) dividedthe Marburg Formation in the Lockyer­Marburg area into two parts: a lowersequence consisting of calcareous lithicsandstone, siltstone, and mudstone, withlesser conglomerate, and an upper sequence(Heifer Creek Sandstone) composed of200 m of 'coarse ferruginous siliceous sand­stone with minor shale and flaggy sandstonebeds.' Casey, Gray, & Reiser (1968) havesuggested that the Marburg Sandstone can­not be subdivided on a regional basis, andrecent work in the Ipswich-Moreton Basinhas shown that even in the type area it isdifficult to distinguish individual members.

In the Surat Basin the Marburg Sandstonecrops out east of Chinchilla around theYarraman Block and to the north of Ingle­wood near the Texas High. East of Chin­chilla (Exon et al., 1968, pp. 48-51) the

exploration companies. Meyers (1970) hassuggested that the lower parts of the HelidonSandstone (most of Meyers' 'Lower Preci­pice') and Precipice Sandstone do not linkup across the Kumbarilla Ridge, and thatthe upper parts join only north of Kum­barilla.

According to Meyers (1970), who madea detailed study of well data, the formationis divisible into a lower shaly part, a middlesandstone part, and an upper sandstone­shale part. The lower shaly sequence is in­terpreted by Hogetoorn (in Meyers, 1970),and the author, as Raceview Formation. Thisinterpretation agrees with the spore evidence(e.g. de Jersey et aI., 1964) and means thatdeposition of the Helidon Sandstone beganwith sand, as in the type area.

Thus there is a lower sandstone sequenceand an upper sandstone-shale sequence inthis area. The lower sequence consists (seeMeyers, 1970) largely of porous coarse­grained quartzose to sublabile sandstone,with a few grey shaly interbeds. The sand­stone contains subangular quartz grains andsome quartz pebbles, and generally has asiliceous cement and a clay matrix. Theupper sequence consists of sandstone andshale in roughly equal proportions. Thesandstone is sublabile, light grey, andgenerally fine to medium-grained; the dastsconsist of sub-rounded quartz, minor lithicgrains and feldspar, and rare red garnet. Therock has a clay matrix and it is generallynon-porous, and is characterized (as in thetype area) by the presence of numerousorange to yellow weathered grains. The grey­ish shaly beds contain 'black oolites' in Phil­lips Wilkie No. I and Cecil Plains No. I.

The Helidon Sandstone rests disconform­ably on the Raceview Formation in muchof the area described in this Bulletin, andunconformably overlies the Permo-Carboni­ferous basement rocks on the KumbarillaRidge. To the west it gives way to the morequartzose Precipice Sandstone, and to theeast to the Ripley Road Sandstone at theWest Ipswich Disturbance.

The sequence is thickest in the CecilPlains Syncline, where 146 m is recordedin the Phillips Cecil Plains No. I well.

83

Meyers (1970) has suggested that the mainsource area was to the cast, and that it con­sisted of metamorphic and possibly igneousrocks. The beds were laid down mainly bystreams, and consist of point-bar and chan­nel sands grading up into overbank deposits.The presence of oolites high in the sequencesuggests shallow-marine incursions.

The miospore assemblages (de Jersey,1971) indicate that the Helidon Sandstoneis of Jurassic age, whereas the apparentlylaterally continuous Ripley Road Sandstoneis mainly Rhaetic (uppermost Triassic) age.Thus deposition of the Ripley Road Sand­stone in the east began before the Helidonand Precipice Sandstone were laid down inthe west.

Marburg SandstoneThe Marburg Sandstone has been studied

by numerous authors, many of whom pre­ferred the name Marburg Formation; thenomenclatural problem has yet to be re­solved.

Reid (1921) subdivided the WalloonCoal measures into the Marburg and Rose­wood Stages. In the type area near Marburgthe formation consists of torrentially cross­bedded calcareous sandstone with someshale, silty sandstone, grit, and conglomer­ate. Swindon (1960) used the term MarburgSandstone in his description of the sandstonein the type area. McTaggart (1963) dividedthe Marburg Formation in the Lockyer­Marburg area into two parts: a lowersequence consisting of calcareous lithicsandstone, siltstone, and mudstone, withlesser conglomerate, and an upper sequence(Heifer Creek Sandstone) composed of200 m of 'coarse ferruginous siliceous sand­stone with minor shale and flaggy sandstonebeds.' Casey, Gray, & Reiser (1968) havesuggested that the Marburg Sandstone can­not be subdivided on a regional basis, andrecent work in the Ipswich-Moreton Basinhas shown that even in the type area it isdifficult to distinguish individual members.

In the Surat Basin the Marburg Sandstonecrops out east of Chinchilla around theYarraman Block and to the north of Ingle­wood near the Texas High. East of Chin­chilla (Exon et al., 1968, pp. 48-51) the

84

formation consists of interbedded sandstoneand siltstone, with minor mudstone and locallenses of conglomerate. Most of the sand­stone is fine to medium-grained and, wherefresh, lithic to lithic sublabile, clayey, andcommonly calcareous; the weathered sand­stone appears to be porous and quartzose.The lithic grains consist mainly of chert andquartzite, with some feldspar, muscovite,biotite, and zircon. The sandstone is gener­ally well bedded and thin to medium­bedded; low-angled cross-bedding and ripplemarks are present in some beds. Thick­bedded, coarser-grained sandstone with high­angled cross-beds, which grades into gritand pebbly sandstone, is also common. Thesubordinate siltstone, which grades intosandstone, is grey, carbonaceous in somebeds, and generally laminated to thin­bedded.

North of Inglewood the outcrops consistexclusively of sandstone, conglomerate, andbreccia. The breccias rest on basement andconsist mainly of quartz fragments, but inplaces rock fragments from the underlyingcherty Palaeozoic rocks are abundant. Thesebasal breccias grade up into coarse andmedium - grained labile, sublabile, andquartzose sandstones. The sandstone ispoorly sorted and consists of angular to sub­rounded grains. It is composed predomin­antly of quartz and matrix, with subordinatefeldspar and rock fragments, and a littlemuscovite, biotite, zircon, and tourmaline.The sandstone cores from well below theweathering profile consist mainly of quartzand clay, and it appears that the labile con­stituents broke down to clay soon afterdeposition. The stratigraphic holes also showthat the sequence contains appreciableamounts of siltstone and mudstone, whichincrease in relative abundance upward.

The Marburg Sandstone in the MoretonBasin is the equivalent of the Evergreen For­mation and Hutton Sandstone in the SuratBasin. In the transitional area of the CecilPlains Syncline the equivalents of the twoSurat Basin units can be recognized in welllogs, but they are here assigned to the Mar­burg Sandstone. Around the margins of thebasin the typical Marburg Sandstone can betraced to the west of the Kumbarilla Ridge

for some distance into the Surat Basin.These marginal beds are the coarser andmore labile equivalents of the basinal Ever­green Formation and Hutton Sandstone.

The Marburg Sandstone conformablyoverlies the Helidon Sandstone in the CecilPlains Syncline, but overlaps it and restsunconformably on basement to the northand south.

The formation was deposited by fast-flow­ing streams draining the Texas High andYarraman Block. The coarse basal polymic­tic conglomerates near the Texas High wereprobably laid down during major floods, andmost of them probably occupy stream val­leys not far from the source areas. As thegradient decreased, progressively finer­grained sandstone and some siltstone weredeposited. The attitude of the cross-beddingindicates northerly to northwesterly-flowingstreams near the Texas High, and westerlyflowing streams near the Yarraman Block.The thickness of the formation ranges from200 to 300 m in the north and south to over500 m in the Cecil Plains Syncline.

Fossils are rare, except for plant impres­sions, most of which are unidentifiable. Reid( 1922) recorded the long-ranging plantsTaeniopteris spatulata and Cladophlebis aus­tralis in the type area, and also the fresh­water bivalves Unio and Unionella? Variouscollections from the Talgai, Thane, andDurikai areas northwest of Warwick haveyielded at least nine plant species that sug­gest an Early Jurassic age for the MarburgSandstone (Gould, 1974b).

The microflora and the conformable rela­tion with the overlying Walloon CoalMeasures (de Jersey, 1963) provide strongevidence that the whole of the MarburgSandstone is Jurassic. Classopollis occursdown to the lowest known outcrop of theformation at Lowood, and forms such aslschyosporites, Taurocusporites, Lycopo­diumsporites rosewoodensis, and Laricoid­ites turbatus are known from Jurassic sedi­ments elsewhere, but have not been foundin the Triassic. Comparison with Jurassicmicrofloras from Western Australia suggeststhat the formation is of Liassic age, but thatit possibly extends into the Bajocian (deJersey, 1963).

84

formation consists of interbedded sandstoneand siltstone, with minor mudstone and locallenses of conglomerate. Most of the sand­stone is fine to medium-grained and, wherefresh, lithic to lithic sublabile, clayey, andcommonly calcareous; the weathered sand­stone appears to be porous and quartzose.The lithic grains consist mainly of chert andquartzite, with some feldspar, muscovite,biotite, and zircon. The sandstone is gener­ally well bedded and thin to medium­bedded; low-angled cross-bedding and ripplemarks are present in some beds. Thick­bedded, coarser-grained sandstone with high­angled cross-beds, which grades into gritand pebbly sandstone, is also common. Thesubordinate siltstone, which grades intosandstone, is grey, carbonaceous in somebeds, and generally laminated to thin­bedded.

North of Inglewood the outcrops consistexclusively of sandstone, conglomerate, andbreccia. The breccias rest on basement andconsist mainly of quartz fragments, but inplaces rock fragments from the underlyingcherty Palaeozoic rocks are abundant. Thesebasal breccias grade up into coarse andmedium - grained labile, sublabile, andquartzose sandstones. The sandstone ispoorly sorted and consists of angular to sub­rounded grains. It is composed predomin­antly of quartz and matrix, with subordinatefeldspar and rock fragments, and a littlemuscovite, biotite, zircon, and tourmaline.The sandstone cores from well below theweathering profile consist mainly of quartzand clay, and it appears that the labile con­stituents broke down to clay soon afterdeposition. The stratigraphic holes also showthat the sequence contains appreciableamounts of siltstone and mudstone, whichincrease in relative abundance upward.

The Marburg Sandstone in the MoretonBasin is the equivalent of the Evergreen For­mation and Hutton Sandstone in the SuratBasin. In the transitional area of the CecilPlains Syncline the equivalents of the twoSurat Basin units can be recognized in welllogs, but they are here assigned to the Mar­burg Sandstone. Around the margins of thebasin the typical Marburg Sandstone can betraced to the west of the Kumbarilla Ridge

for some distance into the Surat Basin.These marginal beds are the coarser andmore labile equivalents of the basinal Ever­green Formation and Hutton Sandstone.

The Marburg Sandstone conformablyoverlies the Helidon Sandstone in the CecilPlains Syncline, but overlaps it and restsunconformably on basement to the northand south.

The formation was deposited by fast-flow­ing streams draining the Texas High andYarraman Block. The coarse basal polymic­tic conglomerates near the Texas High wereprobably laid down during major floods, andmost of them probably occupy stream val­leys not far from the source areas. As thegradient decreased, progressively finer­grained sandstone and some siltstone weredeposited. The attitude of the cross-beddingindicates northerly to northwesterly-flowingstreams near the Texas High, and westerlyflowing streams near the Yarraman Block.The thickness of the formation ranges from200 to 300 m in the north and south to over500 m in the Cecil Plains Syncline.

Fossils are rare, except for plant impres­sions, most of which are unidentifiable. Reid( 1922) recorded the long-ranging plantsTaeniopteris spatulata and Cladophlebis aus­tralis in the type area, and also the fresh­water bivalves Unio and Unionella? Variouscollections from the Talgai, Thane, andDurikai areas northwest of Warwick haveyielded at least nine plant species that sug­gest an Early Jurassic age for the MarburgSandstone (Gould, 1974b).

The microflora and the conformable rela­tion with the overlying Walloon CoalMeasures (de Jersey, 1963) provide strongevidence that the whole of the MarburgSandstone is Jurassic. Classopollis occursdown to the lowest known outcrop of theformation at Lowood, and forms such aslschyosporites, Taurocusporites, Lycopo­diumsporites rosewoodensis, and Laricoid­ites turbatus are known from Jurassic sedi­ments elsewhere, but have not been foundin the Triassic. Comparison with Jurassicmicrofloras from Western Australia suggeststhat the formation is of Liassic age, but thatit possibly extends into the Bajocian (deJersey, 1963).

SURAT BASIN ROCK UNITSOOMINANTLy NON-MARINE JURASSIC TO

LOWERMOST CRETACEOUS SEQUENCE

(Table 19)

Precipice SandstoneThe Precipice Sandstone, as the main pro­

ducer of hydrocarbons in the Surat Basin,is of considerable ecnomic importance. Itconsists mainly of quartzose sandstone, witha coarser lower part and a finer upper partthat contains some siltstone.

The name Precipice Sandstone was firstused by Whitehouse (1952), who definedthe type area (Whitehouse, 1954) as 'thesandstone cliffs in the gorge of PrecipiceCreek, a tributary of the Oawson River' inthe Taroom Sheet area. The type section,which is 45 m thick, was measured in 1964(Mollan, Exon, & Forbes, 1965) and is des­cribed and figured in Mollan et al. (1972).The section consists of fine to very coarse,thinly to very thickly bedded quartzose sand­stone; there is no finer-grained upper part.

The Precipice Sandstone crops out in asinuous east-west belt that terminates to theeast against the Auburn Complex anddefines the northern limit of the Surat Basin.The sandstone commonly crops out in aseries of prominent cliffs. In the subsurface(Fig. 19) it terminates to the northeastagainst the Auburn and Yarraman Highs(see Fig. 6), to the southeast against theTexas High, and to the southwest againstthe St George/Bollon Slope; in the east itgrades laterally into the Helidon Sandstoneof the Moreton Basin, and in the northwestit persists across the Nebine Ridge into theEromanga Basin.

The sandstone is generally white to greywhen fresh, and is mostly quartzose, withminor lithic grains, feldspar, muscovite,mica, and coaly fragments. Red garnet isabundant in some horizons. In places it ispebbly, and interbeds of conglomerate maybe present. The matrix consists of authigenicclay and silica, with a little calcite, siderite,or pyrite. The sandstone is generally thick­bedded and cross-stratified; the cross-bedsare generally planar, although trough cross­bedding also occurs.

85

The upper part of the formation containsthinly bedded sandstone and siltstone inwhich ripple marks, worm trails, and leafimpressions are common. The siltstone isgenerally laminated and micaceous, andcommonly carbonaceous. Thin seams of coaland carbonaceous shale are common, par­ticularly in the Cracow area.

The Precipice Sandstone heralded a wide­spread fluvial transgression. It generally restsunconformably on rocks ranging fromOevonian to Middle Triassic in age, but inthe centre of the basin, where there was littleTriassic movement, it disconformably over­lies the Middle Triassic sequence.

The lack of marine fossils, the abundanceof plant fossils, and the unidirectional cross­stratification indicate that the PrecipiceSandstone is a stream deposit. Whitehouse( ] 952, p. 9]) suggested that the sands weredeposited by streams in large basins, andthat the finer-grained sediment was trans­ported beyond the basins to the sea. Thepresence of large planar cross-beds and thelack of fine material suggest deposition in abraided channel system similar to that of the'channel-country' of central Australia, whereOr J. J. Veevers (pers. comm.) has foundthat sand greatly predominates, and notedthat the only mud deposited is an ephemeralcrust laid down during the waning stage ofeach flood; the mud crust is removed by thenext flood. The reduction in grainsize towardthe top of the formation may indicate adecrease in stream velocity as the gradientdecreased. The excellent subsurface study ofthe Roma Shelf sequence by Sell et al.( 1972) suggests that the Precipice Sand­stone on the shelf was deposited by north­northeasterly flowing streams.

The isopach maps and palaeocurrent data(Figs 19, 20) indicate that the coarseporous lower part of the Precipice Sandstonewas laid down by streams of! the high areas,which probably drained to the northeastthrough the Moura area. Local rises wereleft bare, but the depressions were filled withsediment up to 100 m thick. The thickestdeposits, which overlie the pre-JurassicTaroom Trough, exceed 100 m in theTaroom area. Thick deposits were also laid

SURAT BASIN ROCK UNITSOOMINANTLy NON-MARINE JURASSIC TO

LOWERMOST CRETACEOUS SEQUENCE

(Table 19)

Precipice SandstoneThe Precipice Sandstone, as the main pro­

ducer of hydrocarbons in the Surat Basin,is of considerable ecnomic importance. Itconsists mainly of quartzose sandstone, witha coarser lower part and a finer upper partthat contains some siltstone.

The name Precipice Sandstone was firstused by Whitehouse (1952), who definedthe type area (Whitehouse, 1954) as 'thesandstone cliffs in the gorge of PrecipiceCreek, a tributary of the Oawson River' inthe Taroom Sheet area. The type section,which is 45 m thick, was measured in 1964(Mollan, Exon, & Forbes, 1965) and is des­cribed and figured in Mollan et al. (1972).The section consists of fine to very coarse,thinly to very thickly bedded quartzose sand­stone; there is no finer-grained upper part.

The Precipice Sandstone crops out in asinuous east-west belt that terminates to theeast against the Auburn Complex anddefines the northern limit of the Surat Basin.The sandstone commonly crops out in aseries of prominent cliffs. In the subsurface(Fig. 19) it terminates to the northeastagainst the Auburn and Yarraman Highs(see Fig. 6), to the southeast against theTexas High, and to the southwest againstthe St George/Bollon Slope; in the east itgrades laterally into the Helidon Sandstoneof the Moreton Basin, and in the northwestit persists across the Nebine Ridge into theEromanga Basin.

The sandstone is generally white to greywhen fresh, and is mostly quartzose, withminor lithic grains, feldspar, muscovite,mica, and coaly fragments. Red garnet isabundant in some horizons. In places it ispebbly, and interbeds of conglomerate maybe present. The matrix consists of authigenicclay and silica, with a little calcite, siderite,or pyrite. The sandstone is generally thick­bedded and cross-stratified; the cross-bedsare generally planar, although trough cross­bedding also occurs.

85

The upper part of the formation containsthinly bedded sandstone and siltstone inwhich ripple marks, worm trails, and leafimpressions are common. The siltstone isgenerally laminated and micaceous, andcommonly carbonaceous. Thin seams of coaland carbonaceous shale are common, par­ticularly in the Cracow area.

The Precipice Sandstone heralded a wide­spread fluvial transgression. It generally restsunconformably on rocks ranging fromOevonian to Middle Triassic in age, but inthe centre of the basin, where there was littleTriassic movement, it disconformably over­lies the Middle Triassic sequence.

The lack of marine fossils, the abundanceof plant fossils, and the unidirectional cross­stratification indicate that the PrecipiceSandstone is a stream deposit. Whitehouse( ] 952, p. 9]) suggested that the sands weredeposited by streams in large basins, andthat the finer-grained sediment was trans­ported beyond the basins to the sea. Thepresence of large planar cross-beds and thelack of fine material suggest deposition in abraided channel system similar to that of the'channel-country' of central Australia, whereOr J. J. Veevers (pers. comm.) has foundthat sand greatly predominates, and notedthat the only mud deposited is an ephemeralcrust laid down during the waning stage ofeach flood; the mud crust is removed by thenext flood. The reduction in grainsize towardthe top of the formation may indicate adecrease in stream velocity as the gradientdecreased. The excellent subsurface study ofthe Roma Shelf sequence by Sell et al.( 1972) suggests that the Precipice Sand­stone on the shelf was deposited by north­northeasterly flowing streams.

The isopach maps and palaeocurrent data(Figs 19, 20) indicate that the coarseporous lower part of the Precipice Sandstonewas laid down by streams of! the high areas,which probably drained to the northeastthrough the Moura area. Local rises wereleft bare, but the depressions were filled withsediment up to 100 m thick. The thickestdeposits, which overlie the pre-JurassicTaroom Trough, exceed 100 m in theTaroom area. Thick deposits were also laid

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE

Name Maximum(map symbol) Thickness (m)

MainReferencesRelations

Overlies OralIo Fmwith regional conform­ity despite localscouring

Environment ofDeposition

--------------------Streams, includingbackswamps

Fossils

Spores and pol­len of Kla divi­sion, plants,Unio

Lithology

Well bedded to cross-beddedquartzose to lithic sandstone,in part clayey, calcareous, andpebbly; siltstone and mudstonecommon in outcrop, less com­mon farther into basin. Con­tains aquifers

Outcrop, 30;subsurface, 300

Lower MoogaCretaceous Sandstone(Neocomian) (Klm)

prallo Outcrop, 140;Formation subsurface, 270

(Juo)

UpperJurassic

Gubbera- Outcrop, 45;munda subsurface, 300Sandstone

(Jug)

Upper Hooray Outcrop, 120;Jurassic Sandstone subsurface, 400to Lower (J-Kh)Cretaceous

Fine to medium cross-beddedvery lithic to lithic sublabilesandstone, calcareous, clayey,and in places glauconitic?,grading into polymictic con­glomerate; siltstone and mud­stone, carbonaceous in part;coal; clay, some bentonitic

Cross-bedded quartzose toclayey lithic sandstone, someconglomerate siltstone andmudstone. Contains aquifers

Quartzose to clayey labilesandstone, pebbly in part; silt­stone and mudstone concen­trated largely in upper part;conglomerate. Glauconie atsome levels near Mungallala.Contains aquifers

Spores and pol­len of J6 divi­sion; abundantplant remains in­clude stumps,logs, roots, andleaves

Spores and pol­len of J5 divi­sion, unidentifi­able plant debris

Spores and pol­len of J5, J6,Kla, and Klbdivisions, acrit­archs, plant deb­ris

Streams, swamps,lakes, and possiblybrackish coastalenvironments

Streams

Streams, somebrackish and shal­low-marine en­vironments later

Conformable on OralloFm

Conformable on West­bourne Fm in most ofbasin, and on PilligaSst in S

Conformable on West­bourne Fm. W equiva­lent of GubberamundaSst, Orallo Fm, andBungil Fm

Day (1964),(Gray, 1972)

Reeves (1947),(Gray, 1972)

Exon (1966),Mollan et al.(1972)

marine,and

WestbourneFormation

(Juw)

Middle toUpperJurassic

NorwoodMudstoneMember

Outcrop, 100;subsurface, 200in MimosaSyncline

50

Siltstone and mudstone, car­bonaceous in part; very fineto fine quartzose to labilesandstone. Barite nodules inoutcrop; glauconie in subsur­face in the Wand pyrite in E

Carbonaceous mudstone, ben­tonitic in part; lithic to lithicsublabile sandstone; minorsiltstone and coal

Spores and pollenof J5 division,plant debris,acritarchs inplaces

Spores and pol­len, plants

Shallowshorelinecoastal plain

Swamps andstreams; contem-poraneous explo­sive volcanism

Part of Injune CreekGp. Conformable onSpringbok Sst andAdori Sst; laterallyequivalent to and in­tertongues with upperpart of Pilliga Sst in S

L. part of WestbourneFm E of Mitchell.Mappable in subsur­face only

Exon (1966),Mollan et al.(1972), Gray(1972),Swarbrick et al.(1973),Swarbrick (1973)

Swarbrick et al.(1973),Swarbrick (1973)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE

Name Maximum(map symbol) Thickness (m)

MainReferencesRelations

Overlies OralIo Fmwith regional conform­ity despite localscouring

Environment ofDeposition

--------------------Streams, includingbackswamps

Fossils

Spores and pol­len of Kla divi­sion, plants,Unio

Lithology

Well bedded to cross-beddedquartzose to lithic sandstone,in part clayey, calcareous, andpebbly; siltstone and mudstonecommon in outcrop, less com­mon farther into basin. Con­tains aquifers

Outcrop, 30;subsurface, 300

Lower MoogaCretaceous Sandstone(Neocomian) (Klm)

prallo Outcrop, 140;Formation subsurface, 270

(Juo)

UpperJurassic

Gubbera- Outcrop, 45;munda subsurface, 300Sandstone

(Jug)

Upper Hooray Outcrop, 120;Jurassic Sandstone subsurface, 400to Lower (J-Kh)Cretaceous

Fine to medium cross-beddedvery lithic to lithic sublabilesandstone, calcareous, clayey,and in places glauconitic?,grading into polymictic con­glomerate; siltstone and mud­stone, carbonaceous in part;coal; clay, some bentonitic

Cross-bedded quartzose toclayey lithic sandstone, someconglomerate siltstone andmudstone. Contains aquifers

Quartzose to clayey labilesandstone, pebbly in part; silt­stone and mudstone concen­trated largely in upper part;conglomerate. Glauconie atsome levels near Mungallala.Contains aquifers

Spores and pol­len of J6 divi­sion; abundantplant remains in­clude stumps,logs, roots, andleaves

Spores and pol­len of J5 divi­sion, unidentifi­able plant debris

Spores and pol­len of J5, J6,Kla, and Klbdivisions, acrit­archs, plant deb­ris

Streams, swamps,lakes, and possiblybrackish coastalenvironments

Streams

Streams, somebrackish and shal­low-marine en­vironments later

Conformable on OralloFm

Conformable on West­bourne Fm in most ofbasin, and on PilligaSst in S

Conformable on West­bourne Fm. W equiva­lent of GubberamundaSst, Orallo Fm, andBungil Fm

Day (1964),(Gray, 1972)

Reeves (1947),(Gray, 1972)

Exon (1966),Mollan et al.(1972)

marine,and

WestbourneFormation

(Juw)

Middle toUpperJurassic

NorwoodMudstoneMember

Outcrop, 100;subsurface, 200in MimosaSyncline

50

Siltstone and mudstone, car­bonaceous in part; very fineto fine quartzose to labilesandstone. Barite nodules inoutcrop; glauconie in subsur­face in the Wand pyrite in E

Carbonaceous mudstone, ben­tonitic in part; lithic to lithicsublabile sandstone; minorsiltstone and coal

Spores and pollenof J5 division,plant debris,acritarchs inplaces

Spores and pol­len, plants

Shallowshorelinecoastal plain

Swamps andstreams; contem-poraneous explo­sive volcanism

Part of Injune CreekGp. Conformable onSpringbok Sst andAdori Sst; laterallyequivalent to and in­tertongues with upperpart of Pilliga Sst in S

L. part of WestbourneFm E of Mitchell.Mappable in subsur­face only

Exon (1966),Mollan et al.(1972), Gray(1972),Swarbrick et al.(1973),Swarbrick (1973)

Swarbrick et al.(1973),Swarbrick (1973)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

Name Maximum Environment of(map symbol) Thickness (m) Lithology Fossils Deposition

Adori Outcrop, 60 Fine to medium clayey quart- Spores and pol- StreamsSandstone zose sandstone. Contains aqui- len, plant debris

(Ja) fers

Middle toUpperJurassic

Springbok Outcrop, 60; Fine to coarse labile sand- Spores and pol- Streams, swamps,Sandstone subsurface, 250 stone, calcareous in part, rare len, plants and brackish

(Js) in Mimosa glauconie; siltstone, mudstone, marine in deltasSyncline some coal etc

Relations

Part of Injune CreekGp. Conformable onBirliliead Fm. Equiva­lent, W of NebineRidge, of SpringbokSst, with which itmay intertongue insubsurface

Part of Injune CreekGp. Conformable onWalloon Coal Meas;laterally equivalent toand intertongues withlower part of PilligaSst in S

MainReferences

Exon (1966),Exon, Gallowayet al. (1972 )

Exon (1966),Power & Devine(1970), Mollanet at. (1972),Swarbrick (1973)

MiddleJurassicto UpperCretaceous

Middle toUpperJurassic

MiddleJurassic

KumbarillaBeds

(J-Kk)

PilIigaSandstone

(Jp)

BirkheadFonnation

600

250

100

Lithic to quartzose sandstone,clayey, calcareous in part,grading into conglomerate;siltstone and mudstone, car­bonaceous in part. Containsaquifers

Fine to coarse quartzose sand­stone grading into conglo­merate. Contains excellentaquifers

Mudstone, siltstone, labilesandstone; some calcareous,some carbonaceous. Minorcoal

Spores and pol­len, plant debrisincluding wood

Spores and pol·len, plant debris

Spores and pol­len of J4 and J5divisions, plants

Streams, swamps,and lakes

Streams

Lakes, swamps, andsluggish streams

Heavily weatheredoutcrop equivalent ofsubsurface SpringbokSst-Bungil Fm se­quence on E side ofbasin

Conformable on Wal­loon Coal Meas inthis area and Purla­waugh Fm farther S,equivalent of Spring­bok Sst and West­bourne Fm

Part of Injune CreekGp. Conformable onHutton Sst. NWequivalent of WalloonCoal Meas; confinedto area near and Wof Nebine Ridge

Exon & Vine(1970)

Hind & Helby(1969)

Exon (1966),Exon, Gallowayet al. (1972)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

Name Maximum Environment of(map symbol) Thickness (m) Lithology Fossils Deposition

Adori Outcrop, 60 Fine to medium clayey quart- Spores and pol- StreamsSandstone zose sandstone. Contains aqui- len, plant debris

(Ja) fers

Middle toUpperJurassic

Springbok Outcrop, 60; Fine to coarse labile sand- Spores and pol- Streams, swamps,Sandstone subsurface, 250 stone, calcareous in part, rare len, plants and brackish

(Js) in Mimosa glauconie; siltstone, mudstone, marine in deltasSyncline some coal etc

Relations

Part of Injune CreekGp. Conformable onBirliliead Fm. Equiva­lent, W of NebineRidge, of SpringbokSst, with which itmay intertongue insubsurface

Part of Injune CreekGp. Conformable onWalloon Coal Meas;laterally equivalent toand intertongues withlower part of PilligaSst in S

MainReferences

Exon (1966),Exon, Gallowayet al. (1972 )

Exon (1966),Power & Devine(1970), Mollanet at. (1972),Swarbrick (1973)

MiddleJurassicto UpperCretaceous

Middle toUpperJurassic

MiddleJurassic

KumbarillaBeds

(J-Kk)

PilIigaSandstone

(Jp)

BirkheadFonnation

600

250

100

Lithic to quartzose sandstone,clayey, calcareous in part,grading into conglomerate;siltstone and mudstone, car­bonaceous in part. Containsaquifers

Fine to coarse quartzose sand­stone grading into conglo­merate. Contains excellentaquifers

Mudstone, siltstone, labilesandstone; some calcareous,some carbonaceous. Minorcoal

Spores and pol­len, plant debrisincluding wood

Spores and pol·len, plant debris

Spores and pol­len of J4 and J5divisions, plants

Streams, swamps,and lakes

Streams

Lakes, swamps, andsluggish streams

Heavily weatheredoutcrop equivalent ofsubsurface SpringbokSst-Bungil Fm se­quence on E side ofbasin

Conformable on Wal­loon Coal Meas inthis area and Purla­waugh Fm farther S,equivalent of Spring­bok Sst and West­bourne Fm

Part of Injune CreekGp. Conformable onHutton Sst. NWequivalent of WalloonCoal Meas; confinedto area near and Wof Nebine Ridge

Exon & Vine(1970)

Hind & Helby(1969)

Exon (1966),Exon, Gallowayet al. (1972)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

0000

Name Maximum Environment of(map symbol) Thickness (m) Lithology Fossils Deposition

WaIloon 650 Lithic sublabile to very lithic Spores and pol- Swamps, lakes, andCoal sandstone, siltstone, carbona- len of J4 and J5 sluggish streamsMeasures ceous mudstone, coal. Com- divisions, plants

(Jw) monly calcareous and clayey(montmorillonite)

Middle

Jurassic Eurombah 100 Fine to coarse clayey sublabile Spores and pol- Sluggish streamsFormation sandstone; some polymictic len, plants and swamps

conglomerate, carbonaceoussiltstone, and mudstone

Relations

Part of Injune CreekGp. Conformable onEurombah Fm; whereEurombah Fm is ab­sent conformable onHutlon Sst or Mar­burg Ss!. Surat Basinequivalent of Birk­head Fm

Part of Injune CreekGp. Conformable onHutlon Sst; in N partof basin only. Litho­logy transitional be­tween Hutlon Sst andWalloon Coal Meas

MainReferences

Cameron (1907),Reid (l92l),Gould (1968),Gray (1972),Swarbrick (1973)

Gray (1972),Swarbrick et al.(1973),Swarbrick (1973)

Lower

Jurassic

HuttonSandstone

(JIh)

EvergreenFormation

WestgroveIronstoneMember westof MimosaSyncline axis,and OoliteMembereast of axis

250

260

25

Quartzose to sublabile sand­stone, some siltstone andmudstone, commonly carbona­ceous, minor conglomerate.Contains aquifers

Siltstone, mudstone or shale,carbonaceous in part, lithic toquartzose sandstone, minoroolitic ironstone and coal

Chamositic ironstone, ooliticor pelletal in part, mudstone

Spores and pol­len of 13 and J4divisions, plants

Spores and pol­len of 11 and J2divisions, acrit-archs, plants,rare freshwaterpelecypods

Spores and pol­len of 12 divi­sion, acritarchs,plants. rare fresh­water pelecypods,plant stems andlogs

Streams

Streams, lakes,deltas; partlymarine

Shallow-marine re­ducing environ­ment, with gentlewave or tidalaction

Conformable on Ever­green Fm. Lateralequivalent of upperpart of Marburg Sst

Conformable on Pre­cipice Ss!. Lateralequivalent of lowerpart of Marburg Sst

Within Evergreen Fm.Two oolitic horizonsin subsurface in Mi­mosa Syncline. U.horizon may representWestgrove Ironstone,lower, Oolite Mbr.Oolite Mbr overliesBoxvale Sst

Reeves (1947),Mollan et al.(1972)

Whitehouse(1952),Mollan et al.(1972)

Mollan et aI.(1972)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

0000

Name Maximum Environment of(map symbol) Thickness (m) Lithology Fossils Deposition

WaIloon 650 Lithic sublabile to very lithic Spores and pol- Swamps, lakes, andCoal sandstone, siltstone, carbona- len of J4 and J5 sluggish streamsMeasures ceous mudstone, coal. Com- divisions, plants

(Jw) monly calcareous and clayey(montmorillonite)

Middle

Jurassic Eurombah 100 Fine to coarse clayey sublabile Spores and pol- Sluggish streamsFormation sandstone; some polymictic len, plants and swamps

conglomerate, carbonaceoussiltstone, and mudstone

Relations

Part of Injune CreekGp. Conformable onEurombah Fm; whereEurombah Fm is ab­sent conformable onHutlon Sst or Mar­burg Ss!. Surat Basinequivalent of Birk­head Fm

Part of Injune CreekGp. Conformable onHutlon Sst; in N partof basin only. Litho­logy transitional be­tween Hutlon Sst andWalloon Coal Meas

MainReferences

Cameron (1907),Reid (l92l),Gould (1968),Gray (1972),Swarbrick (1973)

Gray (1972),Swarbrick et al.(1973),Swarbrick (1973)

Lower

Jurassic

HuttonSandstone

(JIh)

EvergreenFormation

WestgroveIronstoneMember westof MimosaSyncline axis,and OoliteMembereast of axis

250

260

25

Quartzose to sublabile sand­stone, some siltstone andmudstone, commonly carbona­ceous, minor conglomerate.Contains aquifers

Siltstone, mudstone or shale,carbonaceous in part, lithic toquartzose sandstone, minoroolitic ironstone and coal

Chamositic ironstone, ooliticor pelletal in part, mudstone

Spores and pol­len of 13 and J4divisions, plants

Spores and pol­len of 11 and J2divisions, acrit-archs, plants,rare freshwaterpelecypods

Spores and pol­len of 12 divi­sion, acritarchs,plants. rare fresh­water pelecypods,plant stems andlogs

Streams

Streams, lakes,deltas; partlymarine

Shallow-marine re­ducing environ­ment, with gentlewave or tidalaction

Conformable on Ever­green Fm. Lateralequivalent of upperpart of Marburg Sst

Conformable on Pre­cipice Ss!. Lateralequivalent of lowerpart of Marburg Sst

Within Evergreen Fm.Two oolitic horizonsin subsurface in Mi­mosa Syncline. U.horizon may representWestgrove Ironstone,lower, Oolite Mbr.Oolite Mbr overliesBoxvale Sst

Reeves (1947),Mollan et al.(1972)

Whitehouse(1952),Mollan et al.(1972)

Mollan et aI.(1972)

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

Name Maximum(map symbol) Thickness (m) Lithology Fossils

Environment ofDeposition Relations

MainReferences

LowerJurassic

BoxvaleSandstoneMember

MarburgSandstone

(Jlm)

HelidonSandstone

(J11)

PrecipiceSandstone

(lIp)

90

500

150

150

Quartzose sandstone, minorsiltstone and coal. Containsaquifers

Clayey feldspathic to sublabilesandstone grading into conglo­merate, siltstone, mudstone.Contains aquifers

Clayey quartzose to sublabilesandstone, pebbly in part,mudstone or shale with someoolites

Quartzose sandstone and peb­bly sandstone, some lithic sub­labile sandstone, siltstone

Spores and pol­len of J1 and 12divisions, plants

Spores and pol­len of J1 and 12divisions, plants

Spores and pol­len of J1 divi­sion, plants

Spores and pol­len of J1 divi­sion, plants

Streams, deltas,and lakes

Streams, deltas,and lakes

Streams, overbankdeposition increas­ed with time

Streams, overbankdeposition increas­ed with time

Within Evergreen Fm.Confined to area Wof axis of MimosaSyncline

Equivalent of HuttonSst and EvergreenFm. Conformable onHelidon Sst, but lapsonto basement

Equivalent of Precip­ice Sst. Disconform­able on Raceview Fm,but laps onto base­ment

Unconformable onolder units rangingfrom Devonian to M.Triassic

Reeves (l947),Mollan et al.(l972)

Reid (1921),Cameron et al.in Hill & Den­mead (1960, pp.288-291), deJersey (1963),Staines (1964)

Dunstan (l915),McTaggart(1963), Meyers(1970), deJersey (1971)

Whitehouse(1952), Mollanet aI. (l972)

MAJOR UNCONFORMITY

TABLE 19. DOMINANTLY NON-MARINE JURASSIC TO LOWER CRETACEOUS SEQUENCE-(cont.)

Name Maximum(map symbol) Thickness (m) Lithology Fossils

Environment ofDeposition Relations

MainReferences

LowerJurassic

BoxvaleSandstoneMember

MarburgSandstone

(Jlm)

HelidonSandstone

(J11)

PrecipiceSandstone

(lIp)

90

500

150

150

Quartzose sandstone, minorsiltstone and coal. Containsaquifers

Clayey feldspathic to sublabilesandstone grading into conglo­merate, siltstone, mudstone.Contains aquifers

Clayey quartzose to sublabilesandstone, pebbly in part,mudstone or shale with someoolites

Quartzose sandstone and peb­bly sandstone, some lithic sub­labile sandstone, siltstone

Spores and pol­len of J1 and 12divisions, plants

Spores and pol­len of J1 and 12divisions, plants

Spores and pol­len of J1 divi­sion, plants

Spores and pol­len of J1 divi­sion, plants

Streams, deltas,and lakes

Streams, deltas,and lakes

Streams, overbankdeposition increas­ed with time

Streams, overbankdeposition increas­ed with time

Within Evergreen Fm.Confined to area Wof axis of MimosaSyncline

Equivalent of HuttonSst and EvergreenFm. Conformable onHelidon Sst, but lapsonto basement

Equivalent of Precip­ice Sst. Disconform­able on Raceview Fm,but laps onto base­ment

Unconformable onolder units rangingfrom Devonian to M.Triassic

Reeves (l947),Mollan et al.(l972)

Reid (1921),Cameron et al.in Hill & Den­mead (1960, pp.288-291), deJersey (1963),Staines (1964)

Dunstan (l915),McTaggart(1963), Meyers(1970), deJersey (1971)

Whitehouse(1952), Mollanet aI. (l972)

MAJOR UNCONFORMITY

90

down in the northwest, where the NebineRidge did not exist during the period whenthe Precipice Sandstone was laid down, andin the Triassic Cecil Plains Syncline, wherethe Helidon Sandstone occurs in place ofthe Precipice Sandstone. The finer-grainedand thinner upper part of the PrecipiceSandstone transgressed farther than thelower part, and few local rises were exposedat the end of Precipice Sandstone time.

About 70 percent of the Roma gas (e.g.Traves, 1971) and all the Moonie oil (e.g.Buckley et al., 1969) occur within porousbeds in the lower part of the Precipice Sand­stone (see pp. 47-54). Along the northernmargin of the basin the Precipice Sandstoneis an important subartesian and artesianaquifer, but it is too deep to be of use else­where.

The total thickness of the formation variesin proportion to the thickness of the lowerpart (see Fig. 20), and is seldom more thanone-third as much again. In the MimosaSyncline and in the northwest the thicknessgenerally exceeds 50 m, whereas on theRoma Shelf and St George/Bollon Slope,and east of the Goondiwindi-Moonie­Burunga Fault Zone, the sequence is gener­ally thinner and decreases outwards.

The formation contains Mesozoic plantsshowing little evolutionary change, andaccurate dating depends solely on palyno­logy. Evans (1964) has reported EarlyJurassic (Liassic) spores from outcrop. andthere have been extensive reports of EarlyJurassic spores from the subsurface (e.g. deJersey & Paten, 1964; Reiser & Williams,1969). Reiser & Williams (1969) includethe Precipice Sandstone in their Classopollisclassoides Zone in which C. classoides is pre­dominant, although Perinopollenites ela­toides, A lisporites spp., and Osmundaciditesspp. are also common. Microplankton havenot been recorded.

Evergreen Formation

The Evergreen Formation, which containssome hydrocarbon reservoirs itself, is widelyregarded as the source rock for much of thehydrocarbons in .the Surat Basin (see pp.45-47). It consists mainly of siltstone, but

shale and sandstone predominate at somehorizons.

Whitehouse (1952, 1954) applied thename Evergreen Shales to the shaly sectionbelow the Boxvale Sandstone (Reeves, 1947)in the valley of the Dawson River imme­diately below Evergreen homestead. Laterstudies by Jensen, Gregory, & Forbes (1964)and Mollan et al. (1965), the results ofwhich were published by Mollan et al.( 1972 ), have shown that even in the typearea there is another shaly sequence, whichincludes the Westgrove Ironstone Memberand the upper part of the Evergreen Forma­tion, above the Boxvale Sandstone.

The type section of the lower part of theEvergreen Formation and the Boxvale Sand­stone has been described by Mollan et al.( 1972 ): the lower part is 100 m thick, andconsists mainly of fine to medium-grainedsublabile to labile sandstone and weatheredmudstone; the Boxvale Sandstone is 40 mthick, and consists, in contrast, of very fineto fine-grained quartzose sandstone.

The type sections of the Westgrove Iron­stone Member and the overlying uppermostshaly part of the Evergreen Formation arein stratigraphic holes Taroom BMR Nos. 46and 54 (Mollan et al.. 1972). The West­grove Ironstone Member is 5 m thick, andconsists of chamositic mudstone and pelletalironstone, and the upper shaly part of theEvergreen Formation consists of 12 m ofsiltstone and mudstone.

The composite type section of the forma­tion is about 160 m thick, and consistsmainly of sandstone (slightly over 50%)and mudstone.

The Evergreen Formation crops out southof the Precipice Sandstone, but overlaps itto the east where, in the vicinity of theYarraman Complex, it grades into the Mar­burg Sandstone; in the subsurface (Fig. 19)it extends farther southwest onto the StGeorge/Bollon Slope, and farther southeastonto the Texas High.

Excluding its two members, the EvergreenFormation is fairly consistent in lithology.The sandstone is mainly fine-grained andcontains abundant lithic and feldspar grains.some mica and carbonaceous grains, and

90

down in the northwest, where the NebineRidge did not exist during the period whenthe Precipice Sandstone was laid down, andin the Triassic Cecil Plains Syncline, wherethe Helidon Sandstone occurs in place ofthe Precipice Sandstone. The finer-grainedand thinner upper part of the PrecipiceSandstone transgressed farther than thelower part, and few local rises were exposedat the end of Precipice Sandstone time.

About 70 percent of the Roma gas (e.g.Traves, 1971) and all the Moonie oil (e.g.Buckley et al., 1969) occur within porousbeds in the lower part of the Precipice Sand­stone (see pp. 47-54). Along the northernmargin of the basin the Precipice Sandstoneis an important subartesian and artesianaquifer, but it is too deep to be of use else­where.

The total thickness of the formation variesin proportion to the thickness of the lowerpart (see Fig. 20), and is seldom more thanone-third as much again. In the MimosaSyncline and in the northwest the thicknessgenerally exceeds 50 m, whereas on theRoma Shelf and St George/Bollon Slope,and east of the Goondiwindi-Moonie­Burunga Fault Zone, the sequence is gener­ally thinner and decreases outwards.

The formation contains Mesozoic plantsshowing little evolutionary change, andaccurate dating depends solely on palyno­logy. Evans (1964) has reported EarlyJurassic (Liassic) spores from outcrop. andthere have been extensive reports of EarlyJurassic spores from the subsurface (e.g. deJersey & Paten, 1964; Reiser & Williams,1969). Reiser & Williams (1969) includethe Precipice Sandstone in their Classopollisclassoides Zone in which C. classoides is pre­dominant, although Perinopollenites ela­toides, A lisporites spp., and Osmundaciditesspp. are also common. Microplankton havenot been recorded.

Evergreen Formation

The Evergreen Formation, which containssome hydrocarbon reservoirs itself, is widelyregarded as the source rock for much of thehydrocarbons in .the Surat Basin (see pp.45-47). It consists mainly of siltstone, but

shale and sandstone predominate at somehorizons.

Whitehouse (1952, 1954) applied thename Evergreen Shales to the shaly sectionbelow the Boxvale Sandstone (Reeves, 1947)in the valley of the Dawson River imme­diately below Evergreen homestead. Laterstudies by Jensen, Gregory, & Forbes (1964)and Mollan et al. (1965), the results ofwhich were published by Mollan et al.( 1972 ), have shown that even in the typearea there is another shaly sequence, whichincludes the Westgrove Ironstone Memberand the upper part of the Evergreen Forma­tion, above the Boxvale Sandstone.

The type section of the lower part of theEvergreen Formation and the Boxvale Sand­stone has been described by Mollan et al.( 1972 ): the lower part is 100 m thick, andconsists mainly of fine to medium-grainedsublabile to labile sandstone and weatheredmudstone; the Boxvale Sandstone is 40 mthick, and consists, in contrast, of very fineto fine-grained quartzose sandstone.

The type sections of the Westgrove Iron­stone Member and the overlying uppermostshaly part of the Evergreen Formation arein stratigraphic holes Taroom BMR Nos. 46and 54 (Mollan et al.. 1972). The West­grove Ironstone Member is 5 m thick, andconsists of chamositic mudstone and pelletalironstone, and the upper shaly part of theEvergreen Formation consists of 12 m ofsiltstone and mudstone.

The composite type section of the forma­tion is about 160 m thick, and consistsmainly of sandstone (slightly over 50%)and mudstone.

The Evergreen Formation crops out southof the Precipice Sandstone, but overlaps itto the east where, in the vicinity of theYarraman Complex, it grades into the Mar­burg Sandstone; in the subsurface (Fig. 19)it extends farther southwest onto the StGeorge/Bollon Slope, and farther southeastonto the Texas High.

Excluding its two members, the EvergreenFormation is fairly consistent in lithology.The sandstone is mainly fine-grained andcontains abundant lithic and feldspar grains.some mica and carbonaceous grains, and

garnet in places. Most of the sandstones areimpermeable owing to the presence of anargillaceous matrix and the abundance ofcalcareous and ferruginous cements. Thesandstone is generally thinly to medium­bedded and well bedded, with some small­scale cross-bedding and ripple marks. Thesiltstone and mudstone are carbonaceousand range from greenish grey to dark grey.Thin seams of coal occur in places.

The Boxvale Sandstone Member, whichis confined to the northwestern part of thebasin, generally west of the axis of theMimosa Syncline, thickens rapidly to thewest of the type section (see pI. 2 in Mollanet aI., 1972). In the type section the topo­graphic relief is fairly subdued, but fartherwest the member consists of upper and lowerscarp-forming sandstones separated by apersistent poorly exposed soft sequence ofsiltstone, sandstone, coal, and ironstone. Themore resistant sandstones are of two types.The first is thickly bedded, cross-bedded,poorly sorted, medium to coarse-grained,and quartzose, and commonly contains anargillaceous matrix. The second is thinlybedded, ripple-marked, well sorted, evenlyand very fine-grained, and quartzose. It ismicaceous and is interbedded with mica­ceous siltstone. Worm tracks are common.

The Westgrove Ironstone Member, inwhich the oolite member of Jensen et al.( 1964) is here included, is more widespreadthan the Boxvale Sandstone Member, andextends right across the northern part of thebasin. It seems to disappear on the Kum­barilla Ridge, but equivalent pelletal iron­stones have been found in the MoretonBasin (Allen, 1971). The composition ofthe pellets and oolites is reported to rangefrom chamosite to siderite, and possibly toglauconite, in different parts of the basin. Inthe east there are commonly two pelletalhorizons separated by dark grey to purplishnon-pelletal mudstone.

The Evergreen Formation generally restsconformably on the Precipice Sandstone, butlaps onto older rocks near basement rises.In places the boundary between the Ever­green Formation and Precipice Sandstone isdifficult to define as the upper finer-grained

91

part of the Precipice Sandstone grades intothe lowermost part of the Evergreen Forma­tion in many wells. In practice the base ofthe lowest thick shaly sequence, which isgenerally over 5 m thick, is taken as the baseof the Evergreen Formation. To the east, inthe vicinity of the Kumbarilla Ridge, theEvergreen Formation grades into the lowerpart of the Marburg Sandstone, its equiva­lent in the MOl'eton Basin.

The degree of marine influence on theEvergreen Formation is uncertain. Thelower part of the formation was probablylaid down by meandering streams, mainly oncoastal plains but possibly also in deltas. Thecoarse, thickbedded, cross-stratified sand­stones within the lower part of the BoxvaleSandstone are stream deposits, but the verywell sorted fine-grained quartzose sandstonesin the upper part of the member may bebeach deposits. They are thinly bedded andcommonly laminated. The low-angle cross­bedding, asymmetrical ripple marks, andanimal tracks lend some support to a beachorigin, although no shelly marine fossils arepresent. Mollan et al. (1972) have sug­gested that the marked grain orientation,good primary porosity, and concentration ofheavy minerals indicate reworking in a lit­toral zone, and concluded that the beds werelaid down in lakes.

Mollan et al. (1972) state that 'thechamositic ironstone members seem to havebeen deposited on the bottom of a moder­ately shallow marine basin, in a reducingenvironment, remote from strong currentaction, but subjected to gentle wave or tidalaction.' A source area of low relief with amarked variation in rainfall seems mostlikely. Most of the evidence presented infavour of this interpretation came from theoolites and their chemistry. The abundanceof acritarchs in the Westgrove IronstoneMember (e.g. Evans, 1964; Reiser & Wil­liams, 1969), and also just below the Box­vale Sandstone in some areas, certainly sug­gests a marine influence.

The lower and uppermost parts of theEvergreen Formation were probably laiddown on a coastal plain, but the BoxvaleSandstone and Westgrove Ironstone Mem-

garnet in places. Most of the sandstones areimpermeable owing to the presence of anargillaceous matrix and the abundance ofcalcareous and ferruginous cements. Thesandstone is generally thinly to medium­bedded and well bedded, with some small­scale cross-bedding and ripple marks. Thesiltstone and mudstone are carbonaceousand range from greenish grey to dark grey.Thin seams of coal occur in places.

The Boxvale Sandstone Member, whichis confined to the northwestern part of thebasin, generally west of the axis of theMimosa Syncline, thickens rapidly to thewest of the type section (see pI. 2 in Mollanet aI., 1972). In the type section the topo­graphic relief is fairly subdued, but fartherwest the member consists of upper and lowerscarp-forming sandstones separated by apersistent poorly exposed soft sequence ofsiltstone, sandstone, coal, and ironstone. Themore resistant sandstones are of two types.The first is thickly bedded, cross-bedded,poorly sorted, medium to coarse-grained,and quartzose, and commonly contains anargillaceous matrix. The second is thinlybedded, ripple-marked, well sorted, evenlyand very fine-grained, and quartzose. It ismicaceous and is interbedded with mica­ceous siltstone. Worm tracks are common.

The Westgrove Ironstone Member, inwhich the oolite member of Jensen et al.( 1964) is here included, is more widespreadthan the Boxvale Sandstone Member, andextends right across the northern part of thebasin. It seems to disappear on the Kum­barilla Ridge, but equivalent pelletal iron­stones have been found in the MoretonBasin (Allen, 1971). The composition ofthe pellets and oolites is reported to rangefrom chamosite to siderite, and possibly toglauconite, in different parts of the basin. Inthe east there are commonly two pelletalhorizons separated by dark grey to purplishnon-pelletal mudstone.

The Evergreen Formation generally restsconformably on the Precipice Sandstone, butlaps onto older rocks near basement rises.In places the boundary between the Ever­green Formation and Precipice Sandstone isdifficult to define as the upper finer-grained

91

part of the Precipice Sandstone grades intothe lowermost part of the Evergreen Forma­tion in many wells. In practice the base ofthe lowest thick shaly sequence, which isgenerally over 5 m thick, is taken as the baseof the Evergreen Formation. To the east, inthe vicinity of the Kumbarilla Ridge, theEvergreen Formation grades into the lowerpart of the Marburg Sandstone, its equiva­lent in the MOl'eton Basin.

The degree of marine influence on theEvergreen Formation is uncertain. Thelower part of the formation was probablylaid down by meandering streams, mainly oncoastal plains but possibly also in deltas. Thecoarse, thickbedded, cross-stratified sand­stones within the lower part of the BoxvaleSandstone are stream deposits, but the verywell sorted fine-grained quartzose sandstonesin the upper part of the member may bebeach deposits. They are thinly bedded andcommonly laminated. The low-angle cross­bedding, asymmetrical ripple marks, andanimal tracks lend some support to a beachorigin, although no shelly marine fossils arepresent. Mollan et al. (1972) have sug­gested that the marked grain orientation,good primary porosity, and concentration ofheavy minerals indicate reworking in a lit­toral zone, and concluded that the beds werelaid down in lakes.

Mollan et al. (1972) state that 'thechamositic ironstone members seem to havebeen deposited on the bottom of a moder­ately shallow marine basin, in a reducingenvironment, remote from strong currentaction, but subjected to gentle wave or tidalaction.' A source area of low relief with amarked variation in rainfall seems mostlikely. Most of the evidence presented infavour of this interpretation came from theoolites and their chemistry. The abundanceof acritarchs in the Westgrove IronstoneMember (e.g. Evans, 1964; Reiser & Wil­liams, 1969), and also just below the Box­vale Sandstone in some areas, certainly sug­gests a marine influence.

The lower and uppermost parts of theEvergreen Formation were probably laiddown on a coastal plain, but the BoxvaleSandstone and Westgrove Ironstone Mem-

92

bers were deposited during a marine trans­gression.

Oil is produced from Evergreen Forma­tion sands in the Alton field (Buckley et al.,1969), and gas (e.g. Traves, 1971) fromsands on the Roma Shelf. Oil is also presentin the Evergreen Formation in UKA ConloiNo. 1 on the eastern side of the MimosaSyncline, west of Miles.

The formation attains its maximum thick­ness of 260 m in the northern and centralparts of the Mimosa Syncline, and in thesouth it is about 100 m thick. East of theGoondiwindi-Moonie-Burunga fault zone theformation thins only slightly away from thesyncline until the basement outcrops areapproached. On the Roma Shelf the thick­ness averages 100 m, but it decreases to thewest and southwest.

The macrofossils include abundant Juras­sic plants (e.g. White in Mollan et al.,1972), and rare pelecypods from the oolitemember, which Dr D. F. McMichael(Mollan et al.. 1972, p. 52) identified as afreshwater mussel, a unionid, and a marineor estuarine mytiloid.

Evans (1964) examined the pollens fromshallow stratigraphic holes, and assignedthe sequence below the oolite member to hisdivision J I, and the oolite member and theoverlying sequence to J2-both of which areof Early Jurassic age. Paten (1967) used thesame divisions. Reiser & Williams (1969)formalized division J] as the Classopolisclassoides Zone, and replaced division J2with an informal Tsugaepollenites segmen­tatus/T. dampieri 'Zone'. Classopollis is pre­dominant in the lower zone (see PrecipiceSandstone), but the more diverse assem­blage in the upper zone contains a decreas­ing proportion of Classopollis, more Lycopo­diumsporites spp. and Osmundacidites spp.,and considerable numbers of A raucaracitesspp., Perinopollenites elatoides, A lisporitesspp., StereisfJorites spp., Cyathidites spp.,and Baculatisporites spp. Acritarchs are ex­ceedingly abundant (over 50% of totalspore, pollen, and acritarch grains) imme­diately above and below the Boxvale Sand­stone in the north. Reiser & Williams (1969)have dated the upper part of the formation

as late Liassic, and state that although thelower part is also probably Liassic it maypossibly be as old as Rhaetic. The generallyaccepted age is Early Jurassic (Liassic).

liutton SandstoneThe name Hutton Sandstone was first used

by Reeves (1947) for sandstone near West­grove Station in the Eddystone Sheet area.The type section is near Hutton Creek east­northeast of Injune (Mollan et al., 1972).In the type area the formation is almostentirely composed of friable fine to medium­grained thick-bedded cross-bedded quartzoseto sublabile sandstone.

The Hutton Sandstone crops out verypoorly across the northern part of the area,and grades into the upper part of the Mar­burg Sandstone on the Kumbarilla Ridge.It is widespread subsurface, where it con­tains more siltstone and mudstone than isapparent in outcrop.

Detailed examination of the rock typescropping out was carried out by Mollan etal. (1972) and subsurface specimens wereexamined by Fehr (1965), Bastian (I 965a),and Houston (1972). The sandstone con­sists predominantly of quartz; the quartzgrains are more angular than those in thePrecipice Sandstone. Some fragments ofmetamorphic and volcanic rocks and feld­spar are also present. The sandstone is gen­erally porous, although kaolinite forms apartial pore-filling; chlorite is common insome beds. The presence of coarse flakes ofmuscovite, and in places biotite and minorgarnet, suggests a metamorphic source area.Calcite cement is fairly common in the sub­surface. The gritty and conglomeratic sand­stones contain large clasts of quartzite,milky quartz, and grey chert, and mud clastsare common in some beds.

The formation is predominantly thicklybedded, with both low and high-angledcross-bedding. Despite quartz overgrowths,and the presence of clay matrix and calcitein many beds, the formation is an importantaquifer.

The Hutton Sandstone conformably over­lies the less sandy more labile and tighterEvergreen Formation. To the east it be­comes steadily more feldspathic and labile

92

bers were deposited during a marine trans­gression.

Oil is produced from Evergreen Forma­tion sands in the Alton field (Buckley et al.,1969), and gas (e.g. Traves, 1971) fromsands on the Roma Shelf. Oil is also presentin the Evergreen Formation in UKA ConloiNo. 1 on the eastern side of the MimosaSyncline, west of Miles.

The formation attains its maximum thick­ness of 260 m in the northern and centralparts of the Mimosa Syncline, and in thesouth it is about 100 m thick. East of theGoondiwindi-Moonie-Burunga fault zone theformation thins only slightly away from thesyncline until the basement outcrops areapproached. On the Roma Shelf the thick­ness averages 100 m, but it decreases to thewest and southwest.

The macrofossils include abundant Juras­sic plants (e.g. White in Mollan et al.,1972), and rare pelecypods from the oolitemember, which Dr D. F. McMichael(Mollan et al.. 1972, p. 52) identified as afreshwater mussel, a unionid, and a marineor estuarine mytiloid.

Evans (1964) examined the pollens fromshallow stratigraphic holes, and assignedthe sequence below the oolite member to hisdivision J I, and the oolite member and theoverlying sequence to J2-both of which areof Early Jurassic age. Paten (1967) used thesame divisions. Reiser & Williams (1969)formalized division J] as the Classopolisclassoides Zone, and replaced division J2with an informal Tsugaepollenites segmen­tatus/T. dampieri 'Zone'. Classopollis is pre­dominant in the lower zone (see PrecipiceSandstone), but the more diverse assem­blage in the upper zone contains a decreas­ing proportion of Classopollis, more Lycopo­diumsporites spp. and Osmundacidites spp.,and considerable numbers of A raucaracitesspp., Perinopollenites elatoides, A lisporitesspp., StereisfJorites spp., Cyathidites spp.,and Baculatisporites spp. Acritarchs are ex­ceedingly abundant (over 50% of totalspore, pollen, and acritarch grains) imme­diately above and below the Boxvale Sand­stone in the north. Reiser & Williams (1969)have dated the upper part of the formation

as late Liassic, and state that although thelower part is also probably Liassic it maypossibly be as old as Rhaetic. The generallyaccepted age is Early Jurassic (Liassic).

liutton SandstoneThe name Hutton Sandstone was first used

by Reeves (1947) for sandstone near West­grove Station in the Eddystone Sheet area.The type section is near Hutton Creek east­northeast of Injune (Mollan et al., 1972).In the type area the formation is almostentirely composed of friable fine to medium­grained thick-bedded cross-bedded quartzoseto sublabile sandstone.

The Hutton Sandstone crops out verypoorly across the northern part of the area,and grades into the upper part of the Mar­burg Sandstone on the Kumbarilla Ridge.It is widespread subsurface, where it con­tains more siltstone and mudstone than isapparent in outcrop.

Detailed examination of the rock typescropping out was carried out by Mollan etal. (1972) and subsurface specimens wereexamined by Fehr (1965), Bastian (I 965a),and Houston (1972). The sandstone con­sists predominantly of quartz; the quartzgrains are more angular than those in thePrecipice Sandstone. Some fragments ofmetamorphic and volcanic rocks and feld­spar are also present. The sandstone is gen­erally porous, although kaolinite forms apartial pore-filling; chlorite is common insome beds. The presence of coarse flakes ofmuscovite, and in places biotite and minorgarnet, suggests a metamorphic source area.Calcite cement is fairly common in the sub­surface. The gritty and conglomeratic sand­stones contain large clasts of quartzite,milky quartz, and grey chert, and mud clastsare common in some beds.

The formation is predominantly thicklybedded, with both low and high-angledcross-bedding. Despite quartz overgrowths,and the presence of clay matrix and calcitein many beds, the formation is an importantaquifer.

The Hutton Sandstone conformably over­lies the less sandy more labile and tighterEvergreen Formation. To the east it be­comes steadily more feldspathic and labile

and grades imperceptibly into the upper partof the Marburg Sandstone of the MoretonBasin above the Kumbarilla Ridge.

The Hutton Sandstone was derived fromvaried, but generally quartz-rich, terrains tothe northeast, southeast, and southwest.Houston (1972) has shown that the sedi­ment varies considerably in composition:near Roma the sandstones contain around20 percent lithic fragments, with somepotash feldspar and varying amounts ofplagioclase; east of Taroom they containabout 50 percent lithic fragments and someplagioclase. The increased lithic content(largely volcanics) and the predominanceof plagioclase over potash feldspar suggestderivation from the Camboon Andesite inthe east. The formation was deposited bymeandering streams on a broad plain. Theisopach map (Fig. 21) indicates that thedrainage was mainly to the north or east.

The thickness of the Hutton Sandstonevaries considerably, but the great variationsin the thickness of the Hutton Sandstone/Walloon Coal Measures (Fig. 21) can beattributed mainly to the Walloon Coal Meas­ures. In most of the basin the Hutton Sand­stone is between 120 and 180 m thick; alongthe relatively active eastern margin it is morevariable, ranging for example from 75 m inUKA Moonie No. 1 to 240 m in UKAUndulla No. 1 60 km to the north.

Plant stems, logs, and small indeterminatepelecypods have been found in the HuttonSandstone (Mollan et al., 1972). Palyno­logical dating (de Jersey & Paten, 1964) sug­gests that most of the formation is EarlyJurassic, but that it probably extends intothe Middle Jurassic. Evans (1966) hasshown that it contains spores of his divisions13 and J4 of Early Jurassic age.

lnjune Creek GroupThe name Injune Creek Group was used

by Exon (1966) to replace the informalname Injune Creek Beds of Jensen (1921),and covers a number of Middle and UpperJurassic non-marine formations. The groupconsists predominantly of mudstone, silt­stone, and labile sandstone, with some cal­careous beds and coal. The group generally

93

crops out poorly in clayey plains that sup­port a calciphile vegetation.

In the Surat Basin the Group typicallycomprises (in ascending order) the Eurom­bah Formation, the Walloon Coal Measures,the Springbok Sandstone, and the West­bourne Formation, and is up to 1000 mthick. In the Eromanga Basin it consists ofthe Birkhead Formation, the Adori Sand­stone, and the Westbourne Formation, andis seldom more than 300 m thick. In thesouthern part of the Surat Basin the Spring­bok Sandstone and Westbourne Formationare replaced by the quartzose Pilliga Sand­stone, and the Eurombah Formation isabsent; although the Walloon Coal Measurespersist into this area the name Injune CreekGroup is no longer applicable.

On the accompanying geological map andcross-sections the various formations withinthe group are not always differentiated, al­though they can generally be identified onwell logs, and in some areas in outcrop.

Eurombah FormationExon (1971) used the name Eurombah

Beds for the sequence which crops out atand near the Eurombah Dome north ofRoma, between the Hutton Sandstone andBirkhead Formation. After the sequence hadbeen drilled by the Queensland Departmentof Mines the name was amended to Eurom­bah Formation by Swarbrick et al. (1973).The type section is in corehole DRD No. 22,near Eurombah homestead on the southwestflank of the Eurombah Dome.

In the type section the upper 50 m con­sists of poorly sorted greenish grey very fineto very coarse-grained labile sandstone andminor conglomerate. The lower 40 m con­sists of interbedded fine-grained greenishgrey labile sandstone and light grey, greenishgrey, or brown mudstone and siltstone;minor pebble bands are present.

On the geological map the EurombahFormation has been included in the un­divided Injune Creek Group, but it is knownto crop out in the north as far west as Injuneand as far east as Wandoan. Subsurface itcan be recognized around the northern mar­gin of the basin from the Nebine Ridge tothe eastern side of the Mimosa Syncline.

and grades imperceptibly into the upper partof the Marburg Sandstone of the MoretonBasin above the Kumbarilla Ridge.

The Hutton Sandstone was derived fromvaried, but generally quartz-rich, terrains tothe northeast, southeast, and southwest.Houston (1972) has shown that the sedi­ment varies considerably in composition:near Roma the sandstones contain around20 percent lithic fragments, with somepotash feldspar and varying amounts ofplagioclase; east of Taroom they containabout 50 percent lithic fragments and someplagioclase. The increased lithic content(largely volcanics) and the predominanceof plagioclase over potash feldspar suggestderivation from the Camboon Andesite inthe east. The formation was deposited bymeandering streams on a broad plain. Theisopach map (Fig. 21) indicates that thedrainage was mainly to the north or east.

The thickness of the Hutton Sandstonevaries considerably, but the great variationsin the thickness of the Hutton Sandstone/Walloon Coal Measures (Fig. 21) can beattributed mainly to the Walloon Coal Meas­ures. In most of the basin the Hutton Sand­stone is between 120 and 180 m thick; alongthe relatively active eastern margin it is morevariable, ranging for example from 75 m inUKA Moonie No. 1 to 240 m in UKAUndulla No. 1 60 km to the north.

Plant stems, logs, and small indeterminatepelecypods have been found in the HuttonSandstone (Mollan et al., 1972). Palyno­logical dating (de Jersey & Paten, 1964) sug­gests that most of the formation is EarlyJurassic, but that it probably extends intothe Middle Jurassic. Evans (1966) hasshown that it contains spores of his divisions13 and J4 of Early Jurassic age.

lnjune Creek GroupThe name Injune Creek Group was used

by Exon (1966) to replace the informalname Injune Creek Beds of Jensen (1921),and covers a number of Middle and UpperJurassic non-marine formations. The groupconsists predominantly of mudstone, silt­stone, and labile sandstone, with some cal­careous beds and coal. The group generally

93

crops out poorly in clayey plains that sup­port a calciphile vegetation.

In the Surat Basin the Group typicallycomprises (in ascending order) the Eurom­bah Formation, the Walloon Coal Measures,the Springbok Sandstone, and the West­bourne Formation, and is up to 1000 mthick. In the Eromanga Basin it consists ofthe Birkhead Formation, the Adori Sand­stone, and the Westbourne Formation, andis seldom more than 300 m thick. In thesouthern part of the Surat Basin the Spring­bok Sandstone and Westbourne Formationare replaced by the quartzose Pilliga Sand­stone, and the Eurombah Formation isabsent; although the Walloon Coal Measurespersist into this area the name Injune CreekGroup is no longer applicable.

On the accompanying geological map andcross-sections the various formations withinthe group are not always differentiated, al­though they can generally be identified onwell logs, and in some areas in outcrop.

Eurombah FormationExon (1971) used the name Eurombah

Beds for the sequence which crops out atand near the Eurombah Dome north ofRoma, between the Hutton Sandstone andBirkhead Formation. After the sequence hadbeen drilled by the Queensland Departmentof Mines the name was amended to Eurom­bah Formation by Swarbrick et al. (1973).The type section is in corehole DRD No. 22,near Eurombah homestead on the southwestflank of the Eurombah Dome.

In the type section the upper 50 m con­sists of poorly sorted greenish grey very fineto very coarse-grained labile sandstone andminor conglomerate. The lower 40 m con­sists of interbedded fine-grained greenishgrey labile sandstone and light grey, greenishgrey, or brown mudstone and siltstone;minor pebble bands are present.

On the geological map the EurombahFormation has been included in the un­divided Injune Creek Group, but it is knownto crop out in the north as far west as Injuneand as far east as Wandoan. Subsurface itcan be recognized around the northern mar­gin of the basin from the Nebine Ridge tothe eastern side of the Mimosa Syncline.

94

In outcrop it consists of thickly beddedcross-bedded fine to coarse-grained clayeylabile sandstone and polymictic conglomer­ate, and thinly bedded to laminated siltstoneand mudstone. In the subsurface (Houston,1972) the sandstones are very kaolinitic andlithic, with siderite a common constituent,and some calcite and chlorite cement. Poro­sity is low. The lithic grains consist predom­inantly of acid to intermediate volcanics.

The Eurombah Formation rests conform­ably between the Hutton Sandstone and theWalloon Coal Measures, but its lateral rela­tion to these units is not clear. Coarsesandstone, pebbly sandstone, and conglom­erate are much more common than in theenclosing formations. The sandstones aremore labile than those of the Hutton Sand­stone and less labile than those of the Wal­loon Coal Measures. Swarbrick et al. (1973)state that on wireline logs 'the base can betaken at the top of the highest resistivitypeak of Hutton Sandstone type, belowwhich the log does not return to the WalloonCoal Measurcs baseline for a considerabledepth.'

The Eurombah Formation was depositedby meandering streams on a broad plain. Incomparison with the Hutton Sandstone, thestreams were less vigorous and there was lessreworking of the sediment.

The formation is 100 m thick near Injune,but thins to the west, south, and cast. It con­tains plants of probable Jurassic age, andBurger (1968) has found spores belongingto Evans' (1966) division J4 of MiddleJurassic age in AAO No. I (Roma).

Walloon Coal MeasuresThe Walloon Beds were named by

Cameron (1907) in the Walloon-Rosewoodarea of the Moreton Basin. Reid (1921)renamed them Walloon Coal Measures andWhitehouse (1954) designated a type areanear Walloon township. Gould (1968)statcd 'the name is now applied to the coalmeasures conformably resting on the . . .Marburg Formation in the Clarence-More­ton Basin.' In the type area, where coalmeasures crop out poorly, the sequence isabout 200 m thick. Samples obtained bydrilling show that the coal measures consist

of light grey mudstone, siltstonl:, fine-grainedclayey lithic sandstone, and thin seams ofcoal. The sandstone has a montmorilloniticmatrix and disintegrates rapidly on expo­sure.

The Walloon Coal Measures crop outextensively in the Moreton Basin. In theSurat Basin they are widespread in the sub­surface, and crop out poorly across thenorthern part of the basin and near thenorthern tip of the Texas High.

Most of the outcrops consist of calcareoussandstone, which occurs mainly as concre­tions. The sandstone is fine to medium­grained, brown or grey, and labile. Beds ofsiltstone, mudstone, coal, and cone-in-conelimestone also crop out, but only wherethere has been rapid recent erosion. Mud­pebble conglomerate occurs at several hori­zons.

Extensive stratigraphic drilling (e.g. Gray,1972; Swarbrick, 1973) has provided muchinformation on the lithology in the northernpart of the basin. Swarbrick (1973) hasshown that a number of sub-units can betraced considerable distances, althoughfacics changes are common. Lithic sandstoneis predominant, but carbonaceous siltstoneand mudstone are common. Coal is rare inthc lower part of thc sequence, abundant inthe middle, and fairly common in the upperpart. The petrological work of Houston( 1972) has shown that the sandstones con­sist mainly of rock fragments and a claymatrix. They contain up to 40 percent quartzand feldspar, and some muscovite, biotite,and chlorite may be present. The rock frag­ments consist predominantly of intermediatevolcanics, but shale and quartzite are alsocommon (Exonetal., 1967).

Although some of the sandstone beds arefairly thick, the coal measures consist mainlyof laminated and thinly bedded sequenccs.The logs of petroleum exploration wells indi­cate that the lithology is fairly consistentthroughout the basin.

The coal measures conformably overliethe Eurombah Formation in the northernpart of the basin, the Hutton Sandstone inthe south, and the Marburg Formation inand near the Cecil Plains Syncline; the con-

94

In outcrop it consists of thickly beddedcross-bedded fine to coarse-grained clayeylabile sandstone and polymictic conglomer­ate, and thinly bedded to laminated siltstoneand mudstone. In the subsurface (Houston,1972) the sandstones are very kaolinitic andlithic, with siderite a common constituent,and some calcite and chlorite cement. Poro­sity is low. The lithic grains consist predom­inantly of acid to intermediate volcanics.

The Eurombah Formation rests conform­ably between the Hutton Sandstone and theWalloon Coal Measures, but its lateral rela­tion to these units is not clear. Coarsesandstone, pebbly sandstone, and conglom­erate are much more common than in theenclosing formations. The sandstones aremore labile than those of the Hutton Sand­stone and less labile than those of the Wal­loon Coal Measures. Swarbrick et al. (1973)state that on wireline logs 'the base can betaken at the top of the highest resistivitypeak of Hutton Sandstone type, belowwhich the log does not return to the WalloonCoal Measurcs baseline for a considerabledepth.'

The Eurombah Formation was depositedby meandering streams on a broad plain. Incomparison with the Hutton Sandstone, thestreams were less vigorous and there was lessreworking of the sediment.

The formation is 100 m thick near Injune,but thins to the west, south, and cast. It con­tains plants of probable Jurassic age, andBurger (1968) has found spores belongingto Evans' (1966) division J4 of MiddleJurassic age in AAO No. I (Roma).

Walloon Coal MeasuresThe Walloon Beds were named by

Cameron (1907) in the Walloon-Rosewoodarea of the Moreton Basin. Reid (1921)renamed them Walloon Coal Measures andWhitehouse (1954) designated a type areanear Walloon township. Gould (1968)statcd 'the name is now applied to the coalmeasures conformably resting on the . . .Marburg Formation in the Clarence-More­ton Basin.' In the type area, where coalmeasures crop out poorly, the sequence isabout 200 m thick. Samples obtained bydrilling show that the coal measures consist

of light grey mudstone, siltstonl:, fine-grainedclayey lithic sandstone, and thin seams ofcoal. The sandstone has a montmorilloniticmatrix and disintegrates rapidly on expo­sure.

The Walloon Coal Measures crop outextensively in the Moreton Basin. In theSurat Basin they are widespread in the sub­surface, and crop out poorly across thenorthern part of the basin and near thenorthern tip of the Texas High.

Most of the outcrops consist of calcareoussandstone, which occurs mainly as concre­tions. The sandstone is fine to medium­grained, brown or grey, and labile. Beds ofsiltstone, mudstone, coal, and cone-in-conelimestone also crop out, but only wherethere has been rapid recent erosion. Mud­pebble conglomerate occurs at several hori­zons.

Extensive stratigraphic drilling (e.g. Gray,1972; Swarbrick, 1973) has provided muchinformation on the lithology in the northernpart of the basin. Swarbrick (1973) hasshown that a number of sub-units can betraced considerable distances, althoughfacics changes are common. Lithic sandstoneis predominant, but carbonaceous siltstoneand mudstone are common. Coal is rare inthc lower part of thc sequence, abundant inthe middle, and fairly common in the upperpart. The petrological work of Houston( 1972) has shown that the sandstones con­sist mainly of rock fragments and a claymatrix. They contain up to 40 percent quartzand feldspar, and some muscovite, biotite,and chlorite may be present. The rock frag­ments consist predominantly of intermediatevolcanics, but shale and quartzite are alsocommon (Exonetal., 1967).

Although some of the sandstone beds arefairly thick, the coal measures consist mainlyof laminated and thinly bedded sequenccs.The logs of petroleum exploration wells indi­cate that the lithology is fairly consistentthroughout the basin.

The coal measures conformably overliethe Eurombah Formation in the northernpart of the basin, the Hutton Sandstone inthe south, and the Marburg Formation inand near the Cecil Plains Syncline; the con-

tacts are transitional. The coal measures arefiner-grained and more labile than the under­lying units. In the west near the NebineRidge, the coal measures grade into themore sandy and less coaly Birkhead Forma­tion of the Eromanga Basin. The sand/shaleratio map of Power & Devine (1970, fig. 10)suggests a meridional transition betweenInjune and Mitchell, where the sequencethins rapidly to the west. In the southwestand southeast the coal measures overlap theHutton Sandstone, and rest directly on base­ment rises.

Most of the sequence was laid down incoal swamps, although the lower part con­sists mainly of stream deposits, especiallyoverbank deposits. The abundance of mont­morillonite and intermediate volcanic debrissuggests contemporaneous volcanism farthereast. The isopach map of the Hutton Sand­stone/Walloon Coal Measures interval (Fig.21), which is dominated by the WalloonCoal Measures, shows that rapid subsidencetook place in the north and east, where thecoal measures are more than 400 m thick.As in Hutton Sandstone time, the drainagewas presumably either to the north or theeast.

The coal measures contain a rich andvaried flora which has been reviewedrecently by Gould (l974a). He reports 'atleast 33 species distributed among the Bryo­phyta, Arthrophyta, Pterophyta, and gymno­sperms. The Coniferophyta are dominant;Ginkgophyta are conspicuously absent.' Healso states that 'the Walloon megaflora con­tains many forms which occur in the Jurassicand Lower Cretaceous', and further that theoccurrence of Osmundacaulis gibbiana'appears to be good evidence in support of aMiddle Jurassic age.' De Jersey & Paten( 1964), who have examined the microflora,have assigned a Middle Jurassic age to thecoal measures in the type area.

Birkhead FormationThe Birkhead Formation (Exon, 1966) is

named after Birkhead Creek, 40 km northof Tambo in the Eromanga Basin, and itstype section is in the Amoseas WestbourneNo. I well. In the Eromanga Basin outcropsconsist mainly of fine-grained sandstone and

95

siltstone, but in the subsurface mudstone iscommon.

The formation crops out along the easternmargin of the Eromanga Basin, and extendsacross the Nebine Ridge into the SuratBasin. Subsurface, it is widespread in theEromanga Basin, and is recognizable in thewesternmost part of the Surat Basin.

In the Surat Basin the formation consistspredominantly of grey, carbonaceous, and inpart calcareous, mudstone and siltstone, butfine-grained labile sandstone with abundantintermediate volcanic fragments is common.Coal is widespread, but relatively unimport­ant.

The Birkhead Formation rests conform­ably on the Hutton Sandstone over mostof the Surat Basin, and is laterally continu­ous with the WalIoon Coal Measures. Thename Birkhead Formation was preferreduntil lateral continuity with the WalloonCoal Measures was proved during theregional mapping program by the BMR andGeological Survey of Queensland (e.g. Exon,1971), and the old name Walloon CoalMeasures can now be applied to the thickcoal-measure sequence that stretches acrossthe Moreton and Surat Basins almost to theNebine Ridge. The sand/shale ratio and iso­pach maps presented by Power & Devine(1970, fig. 10), and our work suggest thatthe two units may be separated by a boun­dary running north-south through Mitchell,to the west of which sand predominates.Furthermore, in the west the sequence isgenerally less than 120 m thick, comparedwith over 200 m in most of the Surat Basin.As only a small area of Birkhead Formationis present in the basin, it has been includedin the Walloon Coal Measures in the mapsand figures.

The Birkhead Formation is probablymainly lacustrine, and is generally less than150 m thick. Most of the abundant plantdebris has not been identified, but palyno­logical evidence points to a Middle Jurassicage (divisions J4 and J5 of Evans, 1966).

Springbok SandstoneThe Springbok Sandstone was named and

defined as the Springbok Sandstone Lens byExon (1966), after the Parish of Springbok

tacts are transitional. The coal measures arefiner-grained and more labile than the under­lying units. In the west near the NebineRidge, the coal measures grade into themore sandy and less coaly Birkhead Forma­tion of the Eromanga Basin. The sand/shaleratio map of Power & Devine (1970, fig. 10)suggests a meridional transition betweenInjune and Mitchell, where the sequencethins rapidly to the west. In the southwestand southeast the coal measures overlap theHutton Sandstone, and rest directly on base­ment rises.

Most of the sequence was laid down incoal swamps, although the lower part con­sists mainly of stream deposits, especiallyoverbank deposits. The abundance of mont­morillonite and intermediate volcanic debrissuggests contemporaneous volcanism farthereast. The isopach map of the Hutton Sand­stone/Walloon Coal Measures interval (Fig.21), which is dominated by the WalloonCoal Measures, shows that rapid subsidencetook place in the north and east, where thecoal measures are more than 400 m thick.As in Hutton Sandstone time, the drainagewas presumably either to the north or theeast.

The coal measures contain a rich andvaried flora which has been reviewedrecently by Gould (l974a). He reports 'atleast 33 species distributed among the Bryo­phyta, Arthrophyta, Pterophyta, and gymno­sperms. The Coniferophyta are dominant;Ginkgophyta are conspicuously absent.' Healso states that 'the Walloon megaflora con­tains many forms which occur in the Jurassicand Lower Cretaceous', and further that theoccurrence of Osmundacaulis gibbiana'appears to be good evidence in support of aMiddle Jurassic age.' De Jersey & Paten( 1964), who have examined the microflora,have assigned a Middle Jurassic age to thecoal measures in the type area.

Birkhead FormationThe Birkhead Formation (Exon, 1966) is

named after Birkhead Creek, 40 km northof Tambo in the Eromanga Basin, and itstype section is in the Amoseas WestbourneNo. I well. In the Eromanga Basin outcropsconsist mainly of fine-grained sandstone and

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siltstone, but in the subsurface mudstone iscommon.

The formation crops out along the easternmargin of the Eromanga Basin, and extendsacross the Nebine Ridge into the SuratBasin. Subsurface, it is widespread in theEromanga Basin, and is recognizable in thewesternmost part of the Surat Basin.

In the Surat Basin the formation consistspredominantly of grey, carbonaceous, and inpart calcareous, mudstone and siltstone, butfine-grained labile sandstone with abundantintermediate volcanic fragments is common.Coal is widespread, but relatively unimport­ant.

The Birkhead Formation rests conform­ably on the Hutton Sandstone over mostof the Surat Basin, and is laterally continu­ous with the WalIoon Coal Measures. Thename Birkhead Formation was preferreduntil lateral continuity with the WalloonCoal Measures was proved during theregional mapping program by the BMR andGeological Survey of Queensland (e.g. Exon,1971), and the old name Walloon CoalMeasures can now be applied to the thickcoal-measure sequence that stretches acrossthe Moreton and Surat Basins almost to theNebine Ridge. The sand/shale ratio and iso­pach maps presented by Power & Devine(1970, fig. 10), and our work suggest thatthe two units may be separated by a boun­dary running north-south through Mitchell,to the west of which sand predominates.Furthermore, in the west the sequence isgenerally less than 120 m thick, comparedwith over 200 m in most of the Surat Basin.As only a small area of Birkhead Formationis present in the basin, it has been includedin the Walloon Coal Measures in the mapsand figures.

The Birkhead Formation is probablymainly lacustrine, and is generally less than150 m thick. Most of the abundant plantdebris has not been identified, but palyno­logical evidence points to a Middle Jurassicage (divisions J4 and J5 of Evans, 1966).

Springbok SandstoneThe Springbok Sandstone was named and

defined as the Springbok Sandstone Lens byExon (1966), after the Parish of Springbok

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Fig. 35. Large-scale grouped cross-bedding in fine-grained snblabile sandstone of the Springbok Sand­stone. East bank of the Maranoa River, 5 km west-northwest of the Amoseas Donnybrook No. 1 well.

in the Roma Sheet area. When its full extentwas realized it was renamed the SpringbokSandstone Membcr (Exon et al., 1967), andlatcr the Springbok Sandstone (Powcr &Devine, 1968). In the type section in BMRMitchell No. 3 it consists of 12 m of feld­spathic sublabile to lithic sandstone.

The formation crops out around thenorthern and eastern sides of thc Surat Basin,but has not becn mapped separately in mostof the area because of the scarcity of goodoutcrop. It is widely recognizable in the sub­surface.

Throughout the basin the sequcnce con­sists mainly of sandstone. with some inter­bedded siltstone and mudstone and a fewthin seams of coal. In outcrop north andwest of Roma (Exon et al., 1967) the sand­stone is generally calcareous and labile. andrangcs from feldspathic to lithic. It is gener-

ally fine-grained, but coarser poorly sortedbeds also occur. Bedding ranges frommedium to vcry thick, and scour and planarcross-beds (Fig. 35) arc common. The cal­cite cement has becn dissolved and redepo­sited as largc ovoid concrctions in certainbeds during the recent weathering cycle.

Subsurface in the north (Exon et al.,1967; Gray. 1972; Swarbrick, 1973;Houston, 1972) the formation consistsmainly of lithic sandstone containing sub­ordinate quartz, abundant feldspar, and con­siderable clay matrix. A calcite cement iscommon in some beds. The minor constitu­ents include biotite. muscovite, magnetite,zircon, rutile, and tourmaline, and a littlegarnet in some beds. The rock fragmentsconsist mainly of green, purple, and blackintermediate volcanics. Swarbrick (1973)has reported that the sequence in GSQ

96

Fig. 35. Large-scale grouped cross-bedding in fine-grained snblabile sandstone of the Springbok Sand­stone. East bank of the Maranoa River, 5 km west-northwest of the Amoseas Donnybrook No. 1 well.

in the Roma Sheet area. When its full extentwas realized it was renamed the SpringbokSandstone Membcr (Exon et al., 1967), andlatcr the Springbok Sandstone (Powcr &Devine, 1968). In the type section in BMRMitchell No. 3 it consists of 12 m of feld­spathic sublabile to lithic sandstone.

The formation crops out around thenorthern and eastern sides of thc Surat Basin,but has not becn mapped separately in mostof the area because of the scarcity of goodoutcrop. It is widely recognizable in the sub­surface.

Throughout the basin the sequcnce con­sists mainly of sandstone. with some inter­bedded siltstone and mudstone and a fewthin seams of coal. In outcrop north andwest of Roma (Exon et al., 1967) the sand­stone is generally calcareous and labile. andrangcs from feldspathic to lithic. It is gener-

ally fine-grained, but coarser poorly sortedbeds also occur. Bedding ranges frommedium to vcry thick, and scour and planarcross-beds (Fig. 35) arc common. The cal­cite cement has becn dissolved and redepo­sited as largc ovoid concrctions in certainbeds during the recent weathering cycle.

Subsurface in the north (Exon et al.,1967; Gray. 1972; Swarbrick, 1973;Houston, 1972) the formation consistsmainly of lithic sandstone containing sub­ordinate quartz, abundant feldspar, and con­siderable clay matrix. A calcite cement iscommon in some beds. The minor constitu­ents include biotite. muscovite, magnetite,zircon, rutile, and tourmaline, and a littlegarnet in some beds. The rock fragmentsconsist mainly of green, purple, and blackintermediate volcanics. Swarbrick (1973)has reported that the sequence in GSQ

Roma Nos. 6 and 7 is characterized byporous, permeable and friable sandstone,especially towards the base. Mudstone is animportant constituent, and coal, mud-pebbleconglomerate, and bentonite are significantminor constituents.

In the Cecil Plains area in the east (Exon,Mond et al., 1972) the subsurface sequenceconsists of a monotonous succession ofclayey fine to medium-grained lithic sand­stones interbedded with carbonaceous andmicaceous siltstone and mudstone. Thesandstone contains up to 5 percent red gar­net.

The Springbok Sandstone rests conform­ably on the much finer-grained Walloon CoalMeasures, although there may be somescouring at the base (Swarbrick, 1973). Theundefined 'Proud Sandstone' in the Romaarea (Traves, 1962) appears to be thepermeable lower part of the SpringbokSandstone. In outcrop the formation pinchesout on the Nebine Ridge, but in the sub­surface it intertongues across the ridge withthe Adori Sandstone of the EromangaBasin. The Adori Sandstone is white, sub­labile, and non-calcareous, whereas theSpringbok Sandstone is green or grey, lithic,and commonly calcareous. In the south theSpringbok Sandstone interfingers with thelower part of the coarse quartzose and highlyporous Pilliga Sandstone (Fig. 22).

The Springbok Sandstone was depositedmainly by streams. The prevalence of over­bank and swamp deposits in the upper partof the sequence indicates that the streamsbecome less vigorous with time. DuringSpringbok Sandstone time the basin was tak­ing up its present configuration, and sedi­ment transport was largely centripetal. Thethickening of the sequence to the east (e.g.Fig. 22) suggests that there was an outletto the east through the Moreton Basin. Thelithic sands derived from the north and east,which contain much bentonite (SpringbokSandstone), indicate contemporaneous vol­canism, whereas the sands from the southwere quartzose (Pilliga Sandstone). TheSpringbok and Pilliga Sandstones inter­tongue in a zone to the north of St Georgeand Goondiwindi (Fig. 22).

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The thickness of the formation generallyranges from 100 to 200 m, with the thickestdeposits where the Springbok Sandstone!Westbourne Formation interval is thickest(Fig. 22). Correlations suggest that inplaces, where there is an increase in thethickness of the Springbok Sandstone, thereis a corresponding decrease in thickness ofthe Westbourne fades, and vice versa.

The plant remains have not been identi­fied, and no palynological results have yetbeen published. On stratigraphic grounds theformation is of late Middle Jurassic and pos­sibly early Late Jurassic age.

A dori SandstoneThe Adori Sandstone (Exon, 1966) is the

Eromanga Basin equivalent of the Spring­bok Sandstone, and is included in it in thesubsurface maps. In the type section north­east of Tambo it consists of 48 m of whiteclayey fine to medium-grained cross-beddedsublabiIe to labile sandstone; similar rocktypes interfinger with the Springbok Sand­stone across the Nebine Ridge. The AdoriSandstone is a stream deposit with a differ­ent (northerly) source area to the SpringbokSandstone.

Westbourne FormationThe Westbourne Formation (Exon, 1966)

is named after the Amoseas WestbourneNo. 1 well 40 km south of Tambo in theEromanga Basin. The type section in thewell consists of 113 m of interbedded mud­stone, siltstone, and very fine-grainedquartzose sandstone.

It crops out around the northern part ofthe Surat Basin, but has been mapped onlyas far east as Gunnewin. In the subsurfaceit is recognizable throughout much of thebasin, although the high-density gamma-raylog, which is a characteristic feature of theformation in the Eromanga Basin, obtainsonly in the northwest.

The outcrops in the Mitchell Sheet areain the northwest include two rock assem­blages in roughly equal proportions. Thefirst consists of grey carbonaceous mica­ceous well-bedded siltstone and mudstone,and the second of buff friable cross-beddedquartz-rich siltstone and very fine-grainedsandstone. The rock assemblages alternate

Roma Nos. 6 and 7 is characterized byporous, permeable and friable sandstone,especially towards the base. Mudstone is animportant constituent, and coal, mud-pebbleconglomerate, and bentonite are significantminor constituents.

In the Cecil Plains area in the east (Exon,Mond et al., 1972) the subsurface sequenceconsists of a monotonous succession ofclayey fine to medium-grained lithic sand­stones interbedded with carbonaceous andmicaceous siltstone and mudstone. Thesandstone contains up to 5 percent red gar­net.

The Springbok Sandstone rests conform­ably on the much finer-grained Walloon CoalMeasures, although there may be somescouring at the base (Swarbrick, 1973). Theundefined 'Proud Sandstone' in the Romaarea (Traves, 1962) appears to be thepermeable lower part of the SpringbokSandstone. In outcrop the formation pinchesout on the Nebine Ridge, but in the sub­surface it intertongues across the ridge withthe Adori Sandstone of the EromangaBasin. The Adori Sandstone is white, sub­labile, and non-calcareous, whereas theSpringbok Sandstone is green or grey, lithic,and commonly calcareous. In the south theSpringbok Sandstone interfingers with thelower part of the coarse quartzose and highlyporous Pilliga Sandstone (Fig. 22).

The Springbok Sandstone was depositedmainly by streams. The prevalence of over­bank and swamp deposits in the upper partof the sequence indicates that the streamsbecome less vigorous with time. DuringSpringbok Sandstone time the basin was tak­ing up its present configuration, and sedi­ment transport was largely centripetal. Thethickening of the sequence to the east (e.g.Fig. 22) suggests that there was an outletto the east through the Moreton Basin. Thelithic sands derived from the north and east,which contain much bentonite (SpringbokSandstone), indicate contemporaneous vol­canism, whereas the sands from the southwere quartzose (Pilliga Sandstone). TheSpringbok and Pilliga Sandstones inter­tongue in a zone to the north of St Georgeand Goondiwindi (Fig. 22).

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The thickness of the formation generallyranges from 100 to 200 m, with the thickestdeposits where the Springbok Sandstone!Westbourne Formation interval is thickest(Fig. 22). Correlations suggest that inplaces, where there is an increase in thethickness of the Springbok Sandstone, thereis a corresponding decrease in thickness ofthe Westbourne fades, and vice versa.

The plant remains have not been identi­fied, and no palynological results have yetbeen published. On stratigraphic grounds theformation is of late Middle Jurassic and pos­sibly early Late Jurassic age.

A dori SandstoneThe Adori Sandstone (Exon, 1966) is the

Eromanga Basin equivalent of the Spring­bok Sandstone, and is included in it in thesubsurface maps. In the type section north­east of Tambo it consists of 48 m of whiteclayey fine to medium-grained cross-beddedsublabiIe to labile sandstone; similar rocktypes interfinger with the Springbok Sand­stone across the Nebine Ridge. The AdoriSandstone is a stream deposit with a differ­ent (northerly) source area to the SpringbokSandstone.

Westbourne FormationThe Westbourne Formation (Exon, 1966)

is named after the Amoseas WestbourneNo. 1 well 40 km south of Tambo in theEromanga Basin. The type section in thewell consists of 113 m of interbedded mud­stone, siltstone, and very fine-grainedquartzose sandstone.

It crops out around the northern part ofthe Surat Basin, but has been mapped onlyas far east as Gunnewin. In the subsurfaceit is recognizable throughout much of thebasin, although the high-density gamma-raylog, which is a characteristic feature of theformation in the Eromanga Basin, obtainsonly in the northwest.

The outcrops in the Mitchell Sheet areain the northwest include two rock assem­blages in roughly equal proportions. Thefirst consists of grey carbonaceous mica­ceous well-bedded siltstone and mudstone,and the second of buff friable cross-beddedquartz-rich siltstone and very fine-grainedsandstone. The rock assemblages alternate

98

with each other in an apparently randommanner.

The weathered sandstones cropping outare quartz-rich, but in the subsurface theyare usually lithic or lithic sublabile andclayey. The clasts consist mainly of quartz,shale, quartzite, and feldspar; some biotiteand muscovite are also present. About 15percent of chlorite and glauconie* pelletswere recorded in a core from BMR MitchellNo. 5. In places the heavy minerals, ironoxides, tourmaline, zircon, and rutile areconcentrated in thin seams. Calcareous con­creations are common, and at one localitybarite nodules up to 5 cm in diameter arepresent. The numerous small-scale planarand scour cross-beds in the thinly tomedium-bedded sandstones have very vari­able azimuth directions.

In the subsurface in the northeast (Swar­brick, 1973; Swarbrick et al., 1973) the for­mation is about 100 m thick; the sequencecan be subdivided into a lower part consist­ing of alternating mudstone and lithic sand­stone with minor siltstone and coal (Nor­wood Mudstone Member), and an upperpart composed of thinly bedded to laminatedsiltstone and impermeable quartzose to sub­labile sandstone (see Fig. 37). The Nor­wood Mudstone contains some bentoniticbeds. Similar rock types are present through­out the basin, but their proportions and dis­tribution vary.

The Westbourne Formation rests con­formably on the Springbok Sandstone, andin much of the southern and eastern parts ofthe basin it is difficult to separate these twoformations. They probably represent differ­ent facies of the same fluvial cycle-theSpringbok Sandstone being laid down byvigorous streams and the Westbourne For­mation by sluggish streams. In the south(Fig. 22) both formations intertongue with,and grade into, the Pilliga Sandstone.

In the Surat Basin the formation consistsmainly of stream deposits laid down bymeandering streams in channels and back-

swamps. The presence of glauconie, heavymineral concentrations, barite nodules, andacritarchs in some beds suggests shallow­marine incursions, presumably in low-lyingareas. The fine-grained quartzose sandstonesof the northwest, which are characterized byhighly variable low-angled cross-bedding,could be beach deposits.

The isopach map of the Springbok Sand­stone/Westbourne Formation interval (Fig.22) suggests that drainage was to the north­east and east, where the thickest sedimentsaccumulated. The thickness of the West­bourne Formation ranges from less than100 m in the west to over 250 m in the east.

No marine macrofossils have been foundin the Westbourne Formation, and none ofthe poorly preserved plant remains havebeen identified. Evans (appendix 2 in Exonet al., 1967) and A. M. Williams (pers.comm.) have recorded Late Jurassic sporesin the samples from stratigraphic holes. Thestratigraphic evidence also indicates a LateJurassic age.

Pilliga SandstoneKenny (1928) named and briefly des­

cribed the Pilliga Series as 'coarse sandstoneand grit with some conglomerate, highly fer­ruginous in most places.' The type area isaround Pilliga township, near Coonabara­bran, after which the formation is named.Dulhunty (1939) used the names PilligaBeds and Pilliga Sandstone and describedthe sequence as 'coarse porous sandstone.'In his discussion of the Mesozoic strati­graphy of the Narrabri-Couradda districtDulhunty ( 1968) used the presentlyaccepted name of Pilliga Sandstone (see, forexample, Hind & Helby, 1969).

The Pilliga Sandstone and its equivalentscrop out for 400 km along the southeasternmargin of the Great Artesian Basin. Theyextend north-northeast from Dubbo in NewSouth Walcs to the Queensland border andbeyond as far as Inglewood. The formationis the main artesian aquifer in northwesternNew South Wales.

* 'Glauconie' is defined by Millot (1970, p. 205) as 'A variable mixture of minerals in which iIIite. mont­morillonite chlorite or various mixed layers can be identified. The total aspect remains that of greenclay miner~ls. but it'is not known whether one part or another yet merits the name "glauconite".' Allthe minerals called 'glauconite' in the Surat'Basin in the past, are better named 'glauconie'; the few thathave been analysed are not glauconite.

98

with each other in an apparently randommanner.

The weathered sandstones cropping outare quartz-rich, but in the subsurface theyare usually lithic or lithic sublabile andclayey. The clasts consist mainly of quartz,shale, quartzite, and feldspar; some biotiteand muscovite are also present. About 15percent of chlorite and glauconie* pelletswere recorded in a core from BMR MitchellNo. 5. In places the heavy minerals, ironoxides, tourmaline, zircon, and rutile areconcentrated in thin seams. Calcareous con­creations are common, and at one localitybarite nodules up to 5 cm in diameter arepresent. The numerous small-scale planarand scour cross-beds in the thinly tomedium-bedded sandstones have very vari­able azimuth directions.

In the subsurface in the northeast (Swar­brick, 1973; Swarbrick et al., 1973) the for­mation is about 100 m thick; the sequencecan be subdivided into a lower part consist­ing of alternating mudstone and lithic sand­stone with minor siltstone and coal (Nor­wood Mudstone Member), and an upperpart composed of thinly bedded to laminatedsiltstone and impermeable quartzose to sub­labile sandstone (see Fig. 37). The Nor­wood Mudstone contains some bentoniticbeds. Similar rock types are present through­out the basin, but their proportions and dis­tribution vary.

The Westbourne Formation rests con­formably on the Springbok Sandstone, andin much of the southern and eastern parts ofthe basin it is difficult to separate these twoformations. They probably represent differ­ent facies of the same fluvial cycle-theSpringbok Sandstone being laid down byvigorous streams and the Westbourne For­mation by sluggish streams. In the south(Fig. 22) both formations intertongue with,and grade into, the Pilliga Sandstone.

In the Surat Basin the formation consistsmainly of stream deposits laid down bymeandering streams in channels and back-

swamps. The presence of glauconie, heavymineral concentrations, barite nodules, andacritarchs in some beds suggests shallow­marine incursions, presumably in low-lyingareas. The fine-grained quartzose sandstonesof the northwest, which are characterized byhighly variable low-angled cross-bedding,could be beach deposits.

The isopach map of the Springbok Sand­stone/Westbourne Formation interval (Fig.22) suggests that drainage was to the north­east and east, where the thickest sedimentsaccumulated. The thickness of the West­bourne Formation ranges from less than100 m in the west to over 250 m in the east.

No marine macrofossils have been foundin the Westbourne Formation, and none ofthe poorly preserved plant remains havebeen identified. Evans (appendix 2 in Exonet al., 1967) and A. M. Williams (pers.comm.) have recorded Late Jurassic sporesin the samples from stratigraphic holes. Thestratigraphic evidence also indicates a LateJurassic age.

Pilliga SandstoneKenny (1928) named and briefly des­

cribed the Pilliga Series as 'coarse sandstoneand grit with some conglomerate, highly fer­ruginous in most places.' The type area isaround Pilliga township, near Coonabara­bran, after which the formation is named.Dulhunty (1939) used the names PilligaBeds and Pilliga Sandstone and describedthe sequence as 'coarse porous sandstone.'In his discussion of the Mesozoic strati­graphy of the Narrabri-Couradda districtDulhunty ( 1968) used the presentlyaccepted name of Pilliga Sandstone (see, forexample, Hind & Helby, 1969).

The Pilliga Sandstone and its equivalentscrop out for 400 km along the southeasternmargin of the Great Artesian Basin. Theyextend north-northeast from Dubbo in NewSouth Walcs to the Queensland border andbeyond as far as Inglewood. The formationis the main artesian aquifer in northwesternNew South Wales.

* 'Glauconie' is defined by Millot (1970, p. 205) as 'A variable mixture of minerals in which iIIite. mont­morillonite chlorite or various mixed layers can be identified. The total aspect remains that of greenclay miner~ls. but it'is not known whether one part or another yet merits the name "glauconite".' Allthe minerals called 'glauconite' in the Surat'Basin in the past, are better named 'glauconie'; the few thathave been analysed are not glauconite.

In New South Wales the formation con­sists mainly of fine to coarse-grained massivesandstone, with some grit, pebbly sandstone,and conglomerate, and minor shale and silt­stone. In outcrop it is commonly ferruginous;in places it is cliff-forming, but elsewhere, asfor example in the Pilliga Scrub country, itforms extensive sandy plains.

The outcrops extending northwards fromaround Yetman to Inglewood consist pre­dominantly of pale yellow to white porousquartzose to sublabile sandstone. The sand­stone is generally medium-grained, with sub­angular to angular grains, and in places con­tains small quartz pebbles and grains of gar­net and feldspar. Some white fine tomedium-grained silty and clayey sandstone,together with thinly bedded siltstone andmudstone containing plant debris, are pres­ent higher in the sequence. Thin beds ofconglomerate and breceia occur throughoutthe formation.

In the subsurface near the Queensland­N.s.W. border (e.g. in the AOG-Harbour­side Werrina No. 1 well) the sandstone isquartzose, but contains subordinate lithicgrains; it is light grey, fine to very coarse­grained, and occasionally pebbly. It containsangular to rounded grains, and is clean,friable, and porous. The logs of petroleumexploration wells (Pis 4, 5) and wireline­logged water-bores show that rare interbedsof shale and siltstone are present. Neareroutcrop, in the continuously cored DMRawdon No. 1 bore, 70 km south of Goondi­windi, the sequence is 100 m thick, and con­sists mainly of porous quartzose sandstone,but contains a considerable proportion ofclayey sandstone, labile sandstone, and silt­stone (Bourke, 1974a). The formation is anexcellent aquifer, and flows of 25 litres persecond are not uncommon.

The Pilliga Sandstone rests unconform­ably on a great variety of older rocks aroundthe margin of the basin and on local base­ment rises within the basin, including theCarboniferous Texas Beds and the Permiangranite outcrops near Yetman. Farther intothe basin it rests with apparent conformityon the Walloon Coal Measures and itssoutherly equivalent, the Purlawaugh For­mation. In the past (e.g. Gould, 1968) it

99

has been equated with the quartz-rich Gub­beramunda Sandstone in the northern partof the Surat Basin, but the present subsur­face studies show (e.g. PIs 4, 5) that itstrue correlates are the labile SpringbokSandstone and the Westbourne Formation,although the Pilliga and GubberamundaSandstone aquifers are in vertical contactbetween Goondiwindi and St George. Thegeneral position of the zone of intertonguingof the Pilliga Sandstone with the SpringbokSandstone and Westbourne Formation isindicated in Figure 22. The Injune CreekGroup is not recognized to the south of thiszone.

The Pilliga Sandstone was laid down bystreams draining to the north, northwest,and west from the Central Western and NewEngland Fold Belts (Fig. 1). The coarsegrainsize and the general lack of overbankdeposits suggest that braided stream systemswere predominant in most of the deposi­tional area; the fine material was presumablyincorporated in the Springbok Sandstone andWestbourne Formation.

The formation is generally about 200 mthick; it thickens to the north from about120 m in the type area to as much as 300 mwest of Moree, but thins towards theQueensland border. In general it is thickerin the centre of the Coonamble Lobe thanalong its eastern margin, but it is apparentthat its original extent to the east and southwas greater than its present extent. The iso­pach map (Fig. 22) shows that the forma­tion is about 230 m thick near Talwood andin the Dirranbandi Syncline, and that it thinsto less than 100 m over the small anticlinesnear St George.

The fossil plants in the formation havenot been identified and no palynological ageshave been published. The formation overliesthe Middle Jurassic Walloon Coal Measuresand Purlawaugh Beds, and is laterally equi­valent to the Upper Jurassic SpringbokSandstone and Westbourne Formation. Thusit is of Late Jurassic age, but possiblyextends slightly into the Middle Jurassic.

Gubberamunda SandstoneThe Gubberamunda Sandstone was

named and mapped by Reeves (1947). Day

In New South Wales the formation con­sists mainly of fine to coarse-grained massivesandstone, with some grit, pebbly sandstone,and conglomerate, and minor shale and silt­stone. In outcrop it is commonly ferruginous;in places it is cliff-forming, but elsewhere, asfor example in the Pilliga Scrub country, itforms extensive sandy plains.

The outcrops extending northwards fromaround Yetman to Inglewood consist pre­dominantly of pale yellow to white porousquartzose to sublabile sandstone. The sand­stone is generally medium-grained, with sub­angular to angular grains, and in places con­tains small quartz pebbles and grains of gar­net and feldspar. Some white fine tomedium-grained silty and clayey sandstone,together with thinly bedded siltstone andmudstone containing plant debris, are pres­ent higher in the sequence. Thin beds ofconglomerate and breceia occur throughoutthe formation.

In the subsurface near the Queensland­N.s.W. border (e.g. in the AOG-Harbour­side Werrina No. 1 well) the sandstone isquartzose, but contains subordinate lithicgrains; it is light grey, fine to very coarse­grained, and occasionally pebbly. It containsangular to rounded grains, and is clean,friable, and porous. The logs of petroleumexploration wells (Pis 4, 5) and wireline­logged water-bores show that rare interbedsof shale and siltstone are present. Neareroutcrop, in the continuously cored DMRawdon No. 1 bore, 70 km south of Goondi­windi, the sequence is 100 m thick, and con­sists mainly of porous quartzose sandstone,but contains a considerable proportion ofclayey sandstone, labile sandstone, and silt­stone (Bourke, 1974a). The formation is anexcellent aquifer, and flows of 25 litres persecond are not uncommon.

The Pilliga Sandstone rests unconform­ably on a great variety of older rocks aroundthe margin of the basin and on local base­ment rises within the basin, including theCarboniferous Texas Beds and the Permiangranite outcrops near Yetman. Farther intothe basin it rests with apparent conformityon the Walloon Coal Measures and itssoutherly equivalent, the Purlawaugh For­mation. In the past (e.g. Gould, 1968) it

99

has been equated with the quartz-rich Gub­beramunda Sandstone in the northern partof the Surat Basin, but the present subsur­face studies show (e.g. PIs 4, 5) that itstrue correlates are the labile SpringbokSandstone and the Westbourne Formation,although the Pilliga and GubberamundaSandstone aquifers are in vertical contactbetween Goondiwindi and St George. Thegeneral position of the zone of intertonguingof the Pilliga Sandstone with the SpringbokSandstone and Westbourne Formation isindicated in Figure 22. The Injune CreekGroup is not recognized to the south of thiszone.

The Pilliga Sandstone was laid down bystreams draining to the north, northwest,and west from the Central Western and NewEngland Fold Belts (Fig. 1). The coarsegrainsize and the general lack of overbankdeposits suggest that braided stream systemswere predominant in most of the deposi­tional area; the fine material was presumablyincorporated in the Springbok Sandstone andWestbourne Formation.

The formation is generally about 200 mthick; it thickens to the north from about120 m in the type area to as much as 300 mwest of Moree, but thins towards theQueensland border. In general it is thickerin the centre of the Coonamble Lobe thanalong its eastern margin, but it is apparentthat its original extent to the east and southwas greater than its present extent. The iso­pach map (Fig. 22) shows that the forma­tion is about 230 m thick near Talwood andin the Dirranbandi Syncline, and that it thinsto less than 100 m over the small anticlinesnear St George.

The fossil plants in the formation havenot been identified and no palynological ageshave been published. The formation overliesthe Middle Jurassic Walloon Coal Measuresand Purlawaugh Beds, and is laterally equi­valent to the Upper Jurassic SpringbokSandstone and Westbourne Formation. Thusit is of Late Jurassic age, but possiblyextends slightly into the Middle Jurassic.

Gubberamunda SandstoneThe Gubberamunda Sandstone was

named and mapped by Reeves (1947). Day

100

Fig. 36. Interbedded sandstone and siltstone of the Gubberamunda Sandstone; the beds probablyrepresent periodic chute-bar deposition in a cut-off meander. Looking east in roadcut 1 km north·west of BMR Roma No. 7, on the Roma.Injune road, 37 km north of Roma. The height of the outcrop

is 4 m.

( 1964) nominated the type area near BungilCreek north of Roma. where the formationconsists of medium to coarse-grained poorlycemented sandstone.

The formation has been mapped acrossthe northern part of the basin, and in theeast it is recognizable in places within theKumbarilla Beds. It is widespread in the sub­surface, but gives way to the Hooray Sand­stone in the west.

The outcrops in the Roma area consist ofquartzose and sublabile sandstone and sub­ordinate conglomerate, siltstone, mudstone,and c1aystone (Exon et al., 1967). Thesandstone beds are generally thick to mass­ive, with common planar and scour cross­bedding, and s01itary cross-bedding in places(Fig. 36). Tile sandstone outcrops have

generally been intensely leached and ferru­ginized, and the clay matrix removed. Thesandstone is composed mainly of quartz,feldspar, and fragments of siItstone, shale,and quartzite, with a little muscovite, biotite.iron oxide, and garnet. Abundant plantimpressions, clay clasts, and mud-balls arepresent in some beds.

The formation is generally coarser-grainedin the east than in the west, and containsextensive polymictic conglomerates, com­posed mainly of basaltic pebbles andcobbles, southwest of Wandoan.

Stratigraphic drilling near Roma (Gray,1972) has shown that in places the sequencecontains roughly equal proportions of sand­stone and thinly bedded laminated silts toneand ll1udstone. The cores contain minor

100

Fig. 36. Interbedded sandstone and siltstone of the Gubberamunda Sandstone; the beds probablyrepresent periodic chute-bar deposition in a cut-off meander. Looking east in roadcut 1 km north·west of BMR Roma No. 7, on the Roma.Injune road, 37 km north of Roma. The height of the outcrop

is 4 m.

( 1964) nominated the type area near BungilCreek north of Roma. where the formationconsists of medium to coarse-grained poorlycemented sandstone.

The formation has been mapped acrossthe northern part of the basin, and in theeast it is recognizable in places within theKumbarilla Beds. It is widespread in the sub­surface, but gives way to the Hooray Sand­stone in the west.

The outcrops in the Roma area consist ofquartzose and sublabile sandstone and sub­ordinate conglomerate, siltstone, mudstone,and c1aystone (Exon et al., 1967). Thesandstone beds are generally thick to mass­ive, with common planar and scour cross­bedding, and s01itary cross-bedding in places(Fig. 36). Tile sandstone outcrops have

generally been intensely leached and ferru­ginized, and the clay matrix removed. Thesandstone is composed mainly of quartz,feldspar, and fragments of siItstone, shale,and quartzite, with a little muscovite, biotite.iron oxide, and garnet. Abundant plantimpressions, clay dasts, and mud-balls arepresent in some beds.

The formation is generally coarser-grainedin the east than in the west, and containsextensive polymictic conglomerates, com­posed mainly of basaltic pebbles andcobbles, southwest of Wandoan.

Stratigraphic drilling near Roma (Gray,1972) has shown that in places the sequencecontains roughly equal proportions of sand­stone and thinly bedded laminated silts toneand ll1udstone. The cores contain minor

101

Fig. 37. Well bedded siltstone and fine sandstone of the Westbourne Formation unconformably over­lain by basal sandstone of the Gubberamunda Sandstone. Looking east in roadcut 2 km northeast ofARO No. 2 well on the Roma-Injune road, 33 km north of Roma. The height of the outcrop is 6 m.

nodular pyrite, and the sandstone generallyhas a high porosity. Houston (1972) hasshown by petrographic examination that thesandstone contains about 50 percent quartz,with abundant pore space, and that feldsparis predominant over lithic (mainly volcanic)grains. The sandstones are more labile thanthey appear in outcrop. Exon & Vine (1970)examined cores from the UKA Cabawin No.I well and reported that the common 'clayeyquartz sands tones' of the subsurface areweathered labile sandstones, which originallyconsisted mainly of quartz and volcanic :-ockfragments. Enough porous beds are presentto make the formation a major aquifer,which yields bicarbonate water.

The Gubberamunda Sandstone is region­ally conformable on the Westbourne Forma­tion but is locally disconformable and over­laps it around the margins of the basin. In

the basalt-cored anticline near Gubbera­munda homestead north of Roma the pres­ence of a local unconformity (Fig. 37) sug­gests that there was some movement in theJurassic. In the southern part of the basin itpersists as a thin sequence, and is recogniz­able in those bores in which it overlies thesilty upper sequence of the Pilliga Sandstone.In the west, on the eastern flank of theNebine Ridge and the St George/BollonSlope, it grades laterally into the lower partof the Hooray Sandstone. This is more achange of na~e than a change of facies, asthe Mooga and Gubberamunda Sandstonearc indistinguishable once the Orallo Forma­tion pinches out (see Fig. 23).

The Gubberamunda Sandstone was depo­sited by braided and meandering stream "sys­terns draining the surrounding highlands.The isopach map (Fig. 23) suggests that

101

Fig. 37. Well bedded siltstone and fine sandstone of the Westbourne Formation unconformably over­lain by basal sandstone of the Gubberamunda Sandstone. Looking east in roadcut 2 km northeast ofARO No. 2 well on the Roma-Injune road, 33 km north of Roma. The height of the outcrop is 6 m.

nodular pyrite, and the sandstone generallyhas a high porosity. Houston (1972) hasshown by petrographic examination that thesandstone contains about 50 percent quartz,with abundant pore space, and that feldsparis predominant over lithic (mainly volcanic)grains. The sandstones are more labile thanthey appear in outcrop. Exon & Vine (1970)examined cores from the UKA Cabawin No.I well and reported that the common 'clayeyquartz sands tones' of the subsurface areweathered labile sandstones, which originallyconsisted mainly of quartz and volcanic :-ockfragments. Enough porous beds are presentto make the formation a major aquifer,which yields bicarbonate water.

The Gubberamunda Sandstone is region­ally conformable on the Westbourne Forma­tion but is locally disconformable and over­laps it around the margins of the basin. In

the basalt-cored anticline near Gubbera­munda homestead north of Roma the pres­ence of a local unconformity (Fig. 37) sug­gests that there was some movement in theJurassic. In the southern part of the basin itpersists as a thin sequence, and is recogniz­able in those bores in which it overlies thesilty upper sequence of the Pilliga Sandstone.In the west, on the eastern flank of theNebine Ridge and the St George/BollonSlope, it grades laterally into the lower partof the Hooray Sandstone. This is more achange of na~e than a change of facies, asthe Mooga and Gubberamunda Sandstonearc indistinguishable once the Orallo Forma­tion pinches out (see Fig. 23).

The Gubberamunda Sandstone was depo­sited by braided and meandering stream "sys­terns draining the surrounding highlands.The isopach map (Fig. 23) suggests that

102

Fig. 38. Large-scale trougb cross-bedding in medium to coarse-grained labile sandstone of tbe OralloFormation at Jobnsons Crossing of Bungeworgorai Creek, on tbe Roma-Orallo road, 33 km nortbwestof Roma. The trougbs average 5 m across and contain clay clasts and pebbles (including silicified

pebbles of fossil wood) at base. The direction of tbe palaeocurrents was to the southeast.

their outlet may have been to the southwestalong the Dirranbandi Syncline.

The thickness is generally about 100 m,but is less around the margin of the basin,and as much as 200 m in the centre of thebasin northeast of St George. Thus thechanges in thickness are generally similar tothose in the entire Gubberamunda Sand­stone/Mooga Sandstone interval shown inFigure 23.

None of the plant remains in the forma­tion have been identified, but spores ofEvans' (1966) division J6, of Late Jurassicage, were reported from the Surat Sheet areaby Thomas & Reiser (1968). On strati­graphic grounds the Gubberamunda Sand­stone is of Late Jurassic age.

Orallo FormationDay (1964) used the name Orallo For­

mation in place of the aralIa Coal Measures

of Jensen (1926,1960), as the sequence hasno known workable coal. The Orallo Forma­tion is the Fossil Wood Stage of Reeves( 1947) and the Fossil Wood Beds of White­house (1954). Day (1964) designated thetype area near Bungeworgorai Creek in thevicinity of Orallo township.

The Orallo Formation has been mappedacross the northern part of the basin, and isrecognizable in places within the KumbarillaBeds in the east (Exon & Vine, 1970). It isgenerally unresistant and crops out poorly.It is widespread in the subsurface, but to thewest gives way to Hooray Sandstone (seeFig. 23).

In outcrop (Exon et al., 1967) thesequence consists of thin-bedded siltstoneand mudstone and thickly bedded cross-stra­tified friable fine to coarse-grained calca­reous lithic sandstone, with minor conglom-

102

Fig. 38. Large-scale trougb cross-bedding in medium to coarse-grained labile sandstone of tbe OralloFormation at Jobnsons Crossing of Bungeworgorai Creek, on tbe Roma-Orallo road, 33 km nortbwestof Roma. The trougbs average 5 m across and contain clay clasts and pebbles (including silicified

pebbles of fossil wood) at base. The direction of tbe palaeocurrents was to the southeast.

their outlet may have been to the southwestalong the Dirranbandi Syncline.

The thickness is generally about 100 m,but is less around the margin of the basin,and as much as 200 m in the centre of thebasin northeast of St George. Thus thechanges in thickness are generally similar tothose in the entire Gubberamunda Sand­stone/Mooga Sandstone interval shown inFigure 23.

None of the plant remains in the forma­tion have been identified, but spores ofEvans' (1966) division J6, of Late Jurassicage, were reported from the Surat Sheet areaby Thomas & Reiser (1968). On strati­graphic grounds the Gubberamunda Sand­stone is of Late Jurassic age.

Orallo FormationDay (1964) used the name Orallo For­

mation in place of the aralIa Coal Measures

of Jensen (1926,1960), as the sequence hasno known workable coal. The Orallo Forma­tion is the Fossil Wood Stage of Reeves( 1947) and the Fossil Wood Beds of White­house (1954). Day (1964) designated thetype area near Bungeworgorai Creek in thevicinity of Orallo township.

The Orallo Formation has been mappedacross the northern part of the basin, and isrecognizable in places within the KumbarillaBeds in the east (Exon & Vine, 1970). It isgenerally unresistant and crops out poorly.It is widespread in the subsurface, but to thewest gives way to Hooray Sandstone (seeFig. 23).

In outcrop (Exon et al., 1967) thesequence consists of thin-bedded siltstoneand mudstone and thickly bedded cross-stra­tified friable fine to coarse-grained calca­reous lithic sandstone, with minor conglom-

103

Fig. 39. Calcareous concentrations in labile sandstone of tbe Orallo Formation at Jobnsons Crossing.Most of tbe concretions lie along the junctions between 'Cross-bedding trougbs. Tbe average tbickness

of tbe concretions is 50 cm.

erate, bentonite, and coal; fossil wood rubbleis widespread. The formation becomes finer­grained upward. The cross-bedding in thecoarser units is dominantly large-scale andoccurs in troughs (Fig. 38).

The original composition varied consider­ably. The rock is leached to varying degrees,and carbonate is concentrated in large elon­gate concretions (Fig. 39) that were com­monly formed along the joints in the cross­bedding troughs. Day (1964), who exa­mined outcrop material, and Houston( 1972), who examined material from strati­graphic holes, have shown that lithic sand­stone predominates in unweathered samples.Houston has shown that in borehole ORDNo. 26 near Roma, the sands tones are con­sistently lithic; they contain about 40 per­cent lithic grains, 20 percent quartz, 20 per­cent feldspar, and considerable clay matrix

and pore space. The lithic grains are pre­dominantly andesitic and trachytic, butgrains of metamorphic rock are common;the feldspar grains consist mainly of plagio­c1ase. Muscovite, biotite, iron oxide, andcalcite or siderite cement are common minorconstituents.

Similar lithic sandstones containing lessthan 40 percent quartz predominatethroughout the basin. Red garnet is commonin the east.

Polymictic conglomerates are widespread,especially low in the sequence, and are par­ticularly abundant in the east (Exon et al.,1968). The clasts commonly consist ofquartz, quartzite, acid porphyry, induratedsediments, trachyte, andesite, basalt, granite,and fossil wood.

Bentonitic clays, and bentonite with goodrheological properties have been described

103

Fig. 39. Calcareous concentrations in labile sandstone of tbe Orallo Formation at Jobnsons Crossing.Most of tbe concretions lie along the junctions between 'Cross-bedding trougbs. Tbe average tbickness

of tbe concretions is 50 cm.

erate, bentonite, and coal; fossil wood rubbleis widespread. The formation becomes finer­grained upward. The cross-bedding in thecoarser units is dominantly large-scale andoccurs in troughs (Fig. 38).

The original composition varied consider­ably. The rock is leached to varying degrees,and carbonate is concentrated in large elon­gate concretions (Fig. 39) that were com­monly formed along the joints in the cross­bedding troughs. Day (1964), who exa­mined outcrop material, and Houston( 1972), who examined material from strati­graphic holes, have shown that lithic sand­stone predominates in unweathered samples.Houston has shown that in borehole ORDNo. 26 near Roma, the sands tones are con­sistently lithic; they contain about 40 per­cent lithic grains, 20 percent quartz, 20 per­cent feldspar, and considerable clay matrix

and pore space. The lithic grains are pre­dominantly andesitic and trachytic, butgrains of metamorphic rock are common;the feldspar grains consist mainly of plagio­c1ase. Muscovite, biotite, iron oxide, andcalcite or siderite cement are common minorconstituents.

Similar lithic sandstones containing lessthan 40 percent quartz predominatethroughout the basin. Red garnet is commonin the east.

Polymictic conglomerates are widespread,especially low in the sequence, and are par­ticularly abundant in the east (Exon et al.,1968). The clasts commonly consist ofquartz, quartzite, acid porphyry, induratedsediments, trachyte, andesite, basalt, granite,and fossil wood.

Bentonitic clays, and bentonite with goodrheological properties have been described

104

Fig. 40. Fossil tree stump in clayey siltstone and fine sandstone of tbe OralJo Formation. Note lateralroot running to the right. Well preserved fronds at tbis locality represent a Taeniopteroid, a conifer,and a fem. In unnamed tributary of Nine Mile Creek immediately north of junction and 11 km north-

west of Miles.

from outcrops and shallow holes betweenOrallo and Miles (Duff & Milligan. 1967;Exon & Duff, 1968 ; Gray. 1972). Beds areup to 2 m thick and have formed by theweathering of fine-grained tuff composed ofandesitic glass shards.

The Orallo Formation rests conformablyon the Gubberamunda Sandstone over mostof the basin. and on the PilIiga Sandstone inthe south. The contact is gradational in thecentral part of the basin. In the west theformation thins towards the Nebine Ridgeand up the St George/Bollon Slope, andeventually pinches out (PIs 2. 3). Wherethe Orallo Formation is absent. the Gub­beramunda and Mooga Sandstones can nolonger be distinguished separately and thecombined unit ,is mapped as the HooraySandstone.

The Orallo Formation was deposited bystreams that generally flowed toward thecentre of the Surat Basin. On the KumbarillaRidge the direction of flow was to the eastinto the Moreton Basin (Fig. 23). but thegeneral trends of the isopachs suggest thatthe main outlet of the basin was to thesouth, along the Dirranbandi Syncline. Alter­natively, the widespread distribution of car­bonate and thin coal seams suggests thatthe area may have been an internal drainagebasin. Coarser sand and gravel were depo­sited in stream channels. and fine sand. silt,and mud in overbank deposits. The sourcematerial was largely volcanic. and the ben­tonite beds indicate contemporaneous explo­sive volcanism. In some areas. where thesequence was weathered before burial. therock fragments were altered to clay. The

104

Fig. 40. Fossil tree stump in clayey siltstone and fine sandstone of tbe OralJo Formation. Note lateralroot running to the right. Well preserved fronds at tbis locality represent a Taeniopteroid, a conifer,and a fem. In unnamed tributary of Nine Mile Creek immediately north of junction and 11 km north-

west of Miles.

from outcrops and shallow holes betweenOrallo and Miles (Duff & Milligan. 1967;Exon & Duff, 1968 ; Gray. 1972). Beds areup to 2 m thick and have formed by theweathering of fine-grained tuff composed ofandesitic glass shards.

The Orallo Formation rests conformablyon the Gubberamunda Sandstone over mostof the basin. and on the PilIiga Sandstone inthe south. The contact is gradational in thecentral part of the basin. In the west theformation thins towards the Nebine Ridgeand up the St George/Bollon Slope, andeventually pinches out (PIs 2. 3). Wherethe Orallo Formation is absent. the Gub­beramunda and Mooga Sandstones can nolonger be distinguished separately and thecombined unit ,is mapped as the HooraySandstone.

The Orallo Formation was deposited bystreams that generally flowed toward thecentre of the Surat Basin. On the KumbarillaRidge the direction of flow was to the eastinto the Moreton Basin (Fig. 23). but thegeneral trends of the isopachs suggest thatthe main outlet of the basin was to thesouth, along the Dirranbandi Syncline. Alter­natively, the widespread distribution of car­bonate and thin coal seams suggests thatthe area may have been an internal drainagebasin. Coarser sand and gravel were depo­sited in stream channels. and fine sand. silt,and mud in overbank deposits. The sourcematerial was largely volcanic. and the ben­tonite beds indicate contemporaneous explo­sive volcanism. In some areas. where thesequence was weathered before burial. therock fragments were altered to clay. The

105

Fig. 41. Planar cross-bedding in fine to medium-grained sandstone in the basal part of the MoogaSandstone overlain by well bedded fine sandstone and siltstone. In bend of Bungeworgorai Creek, 4 kmeast of the ARO No. 10 well, immediately north of the Roma-orallo road, 29 km northwest of Roma.

presence of tree trunks in living positionnear Miles (Fig. 40) shows that after thesoils were formed they were rapidly coveredby sediment.

The variations in thickness are similar tothose of the Gubberamunda Sandstone!Mooga Sandstone interval. The formation isabout 150 m thick in the north, and up to250 m thick in the central and southernparts of the basin, but thins to zero to thewest.

Both fossil wood and leaves are abundant;8 species are listed by Day (1964) and dis­cussed by Gould (1974a), and 15 speciesare listed by White (1967b). The flora sug­gests a Jurassic or Early Cretaceous age.Spores of Evans' (1966) division J6 of LateJurassic age are present and, although theformation possibly ranges into the EarlyCretaceous, its age is generally accepted asLate Jurassic.

Mooga Sandstone

The Mooga Sandstone was named andmapped by Reeves (1947). Day (1964)included it as a member of his BythesdaleFormation, and nominated a type area. TheMooga Sandstone was re-established as aformation by Exon & Vine (1970), who alsoslightly modified the type area north ofRoma. In the type area, where the formationis 30 m thick, it consists mainly of quartzoseto sublabile sandstone.

The formation has been mapped acrossthe northern part of the basin, and is presentwithin the Kumbarilla Beds in the east. It iswidespread in the subsurface, but gives wayin the west to the Hooray Sandstone.

In the general outcrop area the lithologyis variable. but three major subunits arecommonly identifiable (Exon et al., 1967).The lower subunit is generally less than 5 m

105

Fig. 41. Planar cross-bedding in fine to medium-grained sandstone in the basal part of the MoogaSandstone overlain by well bedded fine sandstone and siltstone. In bend of Bungeworgorai Creek, 4 kmeast of the ARO No. 10 well, immediately north of the Roma-orallo road, 29 km northwest of Roma.

presence of tree trunks in living positionnear Miles (Fig. 40) shows that after thesoils were formed they were rapidly coveredby sediment.

The variations in thickness are similar tothose of the Gubberamunda Sandstone!Mooga Sandstone interval. The formation isabout 150 m thick in the north, and up to250 m thick in the central and southernparts of the basin, but thins to zero to thewest.

Both fossil wood and leaves are abundant;8 species are listed by Day (1964) and dis­cussed by Gould (1974a), and 15 speciesare listed by White (1967b). The flora sug­gests a Jurassic or Early Cretaceous age.Spores of Evans' (1966) division J6 of LateJurassic age are present and, although theformation possibly ranges into the EarlyCretaceous, its age is generally accepted asLate Jurassic.

Mooga Sandstone

The Mooga Sandstone was named andmapped by Reeves (1947). Day (1964)included it as a member of his BythesdaleFormation, and nominated a type area. TheMooga Sandstone was re-established as aformation by Exon & Vine (1970), who alsoslightly modified the type area north ofRoma. In the type area, where the formationis 30 m thick, it consists mainly of quartzoseto sublabile sandstone.

The formation has been mapped acrossthe northern part of the basin, and is presentwithin the Kumbarilla Beds in the east. It iswidespread in the subsurface, but gives wayin the west to the Hooray Sandstone.

In the general outcrop area the lithologyis variable. but three major subunits arecommonly identifiable (Exon et al., 1967).The lower subunit is generally less than 5 m

106

thick and consists of sublabile to quartzosesandstone, which is commonly conglomer­atic. The beds are generally massive, andhigh-angled cross-bedding is common (Fig.41 ). The middle subunit is of similar thick­ness and consists essentially of massive darkgrey mudstone, while the upper is generallythe thickest, and consists of thinly beddedfine to medium-grained sublabile sandstonewith some lenses of pebbles and thin shalysiltstone. In places the upper subunit alsocontains labile sandstone and calcareousconcretions.

In stratigraphic hole DRD No. 27 nearthe type area (Gray, 1972) thinly inter­bedded fine-grained sublabile sandstone andsiltstone predominate above the basal sand­stone sequence. The sandstone is commonlycalcareous. Houston (1972) examined theunweathered sandstones from this hole, andhas shown that they range from lithic sub­labile to lithic. The lithic fragments consistmainly of volcanic rocks and the feldspar ispredominantly plagioclase. The apparentporosity ranges up to 20 percent and thereis very little clay matrix and calcite.

Similar sandstones predominate in thesubsurface throughout the area, but siltstoneand mudstone are also common, and in thecentral part of the basin they form nearlyhalf the sequence.

The Mooga Sandstone is generally region­ally conformable on the arallo Formation,although local disconformities occur. In thewest, on the flank of the Nebine Ridge andthe St George/Goondiwindi Slope, it over­laps the arallo Formation and rests directlyon the Gubberamunda Sandstone. In theEromanga Basin the Mooga and Gubbera­munda Sandstones cannot be distinguishedseparately and the combined sequence ismapped as the Hooray Sandstone. TheMooga Sandstone consists of a number ofquartz-rich sand bodies and intervening finersediments, and it is the sand bodies whichdistinguish the formation from the under­lying arallo Formation or overlying BungilFormation (see well correlation diagrams).As the sand occurs as discontinuous lenses,the upper and lower boundaries of the for­mation tend to move up and down the strati­graphic column. The Mooga Sandstone can

generally be distinguished from the aralloand Bungil Formations by the comparativeabundance of porous aquifers containingbicarbonate water.

The Mooga Sandstone was deposited bystreams draining the surrounding higherareas; the streams flowed perhaps to thesouthwest along the depression occupied bythe Dirranbandi Syncline. The sands weremore strongly reworked than those of theunderlying arallo Formation, and hence arebetter sorted and less labile. Around themargins of the basin both braided (especiallyinitially) and meandering stream systemsdeveloped, but farther into the basin, wheregradients were lower, abundant overbankdeposits were laid down by meanderingstreams.

In the north, east, and south the MoogaSandstone is seldom over 100 m thick, butin the central area it thickens to as much as200 m. The variations in thickness aregenerally similar to those of the Gubbera­munda and Mooga Sandstones (Fig. 23).

The formation commonly contains plantremains; Day (1964) identified ten speciesin the Roma area, most of which are long­ranging Jurassic to Early Cretaceous forms.Marine macrofossils have not been found,but Day (1964) found Unio sp. at onelocality. The spores (e.g. Burger, 1972)belong to Evans' (1966) division K I a ofNeocomian age. The Mooga Sandstone isthus, and on stratigraphic grounds, ofearliest Cretaceous age.

Hooray SandstoneThe Hooray Sandstone was named by Hill

& Denmead (1960), and a formal definitionand type section were presented by Exon( 1966). The type section in Hooray Creek,10 km east-northeast of Tambo in the Ero­manga Basin, consists of 75 m of very fine­grained to pebbly white sublabile sandstoneand conglomerate.

The formation is widespread in the sub­surface in the Eromanga Basin and crops outaround the northeastern margin of the basin(Exon, Galloway et al., 1972). It crops outin the northwestern part of the Surat Basin(Mollan et al., 1972), and occurs in thesubsurface west of a meridional line extend-

106

thick and consists of sublabile to quartzosesandstone, which is commonly conglomer­atic. The beds are generally massive, andhigh-angled cross-bedding is common (Fig.41 ). The middle subunit is of similar thick­ness and consists essentially of massive darkgrey mudstone, while the upper is generallythe thickest, and consists of thinly beddedfine to medium-grained sublabile sandstonewith some lenses of pebbles and thin shalysiltstone. In places the upper subunit alsocontains labile sandstone and calcareousconcretions.

In stratigraphic hole DRD No. 27 nearthe type area (Gray, 1972) thinly inter­bedded fine-grained sublabile sandstone andsiltstone predominate above the basal sand­stone sequence. The sandstone is commonlycalcareous. Houston (1972) examined theunweathered sandstones from this hole, andhas shown that they range from lithic sub­labile to lithic. The lithic fragments consistmainly of volcanic rocks and the feldspar ispredominantly plagioclase. The apparentporosity ranges up to 20 percent and thereis very little clay matrix and calcite.

Similar sandstones predominate in thesubsurface throughout the area, but siltstoneand mudstone are also common, and in thecentral part of the basin they form nearlyhalf the sequence.

The Mooga Sandstone is generally region­ally conformable on the arallo Formation,although local disconformities occur. In thewest, on the flank of the Nebine Ridge andthe St George/Goondiwindi Slope, it over­laps the arallo Formation and rests directlyon the Gubberamunda Sandstone. In theEromanga Basin the Mooga and Gubbera­munda Sandstones cannot be distinguishedseparately and the combined sequence ismapped as the Hooray Sandstone. TheMooga Sandstone consists of a number ofquartz-rich sand bodies and intervening finersediments, and it is the sand bodies whichdistinguish the formation from the under­lying arallo Formation or overlying BungilFormation (see well correlation diagrams).As the sand occurs as discontinuous lenses,the upper and lower boundaries of the for­mation tend to move up and down the strati­graphic column. The Mooga Sandstone can

generally be distinguished from the aralloand Bungil Formations by the comparativeabundance of porous aquifers containingbicarbonate water.

The Mooga Sandstone was deposited bystreams draining the surrounding higherareas; the streams flowed perhaps to thesouthwest along the depression occupied bythe Dirranbandi Syncline. The sands weremore strongly reworked than those of theunderlying arallo Formation, and hence arebetter sorted and less labile. Around themargins of the basin both braided (especiallyinitially) and meandering stream systemsdeveloped, but farther into the basin, wheregradients were lower, abundant overbankdeposits were laid down by meanderingstreams.

In the north, east, and south the MoogaSandstone is seldom over 100 m thick, butin the central area it thickens to as much as200 m. The variations in thickness aregenerally similar to those of the Gubbera­munda and Mooga Sandstones (Fig. 23).

The formation commonly contains plantremains; Day (1964) identified ten speciesin the Roma area, most of which are long­ranging Jurassic to Early Cretaceous forms.Marine macrofossils have not been found,but Day (1964) found Unio sp. at onelocality. The spores (e.g. Burger, 1972)belong to Evans' (1966) division K I a ofNeocomian age. The Mooga Sandstone isthus, and on stratigraphic grounds, ofearliest Cretaceous age.

Hooray SandstoneThe Hooray Sandstone was named by Hill

& Denmead (1960), and a formal definitionand type section were presented by Exon( 1966). The type section in Hooray Creek,10 km east-northeast of Tambo in the Ero­manga Basin, consists of 75 m of very fine­grained to pebbly white sublabile sandstoneand conglomerate.

The formation is widespread in the sub­surface in the Eromanga Basin and crops outaround the northeastern margin of the basin(Exon, Galloway et al., 1972). It crops outin the northwestern part of the Surat Basin(Mollan et al., 1972), and occurs in thesubsurface west of a meridional line extend-

ing through Mitchell and Dirranbandi (Fig.23 ).

The sequence cropping out in the north­western part of the Surat Basin (Mollan etal., 1972) is about 120 m thick. It consistsmainly of sandstone, which ranges fromporous and quartzose to clayey and lithic;the main rock type is a white clayey eoarse­grained sublabile sandstone, containing scat­tered pebbles. The sandstone is generallymedium to thick-bedded, with abundanthigh-angled cross-bedding; some worm tubesare present. The sandstones are commonlyporous and consist of about 50 percentquartz, 15 percent fine-grained sediments.and 10 percent feldspar, set in a clay matrix.Some iron oxide, mica, zircon, and tour­maline may be present. Thick-bedded cross­stratified conglomerate is widespread. Itgenerally contains pebbles of quartz, acidvolcanies, chert, sediments and, less com­monly, fossil wood, set in a white sandstonematrix.

In the south near the Maranoa Anticline(Exon et al., 1967) the formation is finer­grained. Beds of white clayey siltstone andclaystone are common, especially in theupper part of the sequence. The uppersequence, which is about 50 m thick, con­sists essentially of thinly to thickly bedded,but rarely cross-bedded, very fine to fine­grained clayey sandstone, and laminated tothinly bedded white clayey siltstone. The silt­stone commonly contains plant remains andmicaceous partings. Below the upper se­quence is a poorly exposed siltstone se­quence, perhaps 30 m thick, consisting ofthinly bedded siltstone, fine-grained clayeysandstone, and white c1aystone. The lowerpart of the formation consists mainly of fine­grained sandstone.

Subsurface the Hooray Sandstone isthicker than in outcrop, and contains excel­lent aquifers that yield bicarbonate water.In the Amoseas Scalby No. I well (Hamilton.1966) the sequence consists chiefly of whiteto grey quartzose sandstone, of variablegrainsize, with a white clay matrix. Inter­beds of grey silty to sandy carbonaceousmudstone and grey argillaceous carbona­ceous siltstone are common, and there arealso few thin seams of coal.

IO?

The Hooray Sandstone generally overliesthe much finer-grained Westbourne Forma­tion with regional conformity, but local dis­conformities are not uncommon. In thesouth it overlaps the Westbourne Formationand rests directly on basement rocks. It isgenerally laterally equivalent to the Gub­beramunda Sandstone, Grallo Formation,and Mooga Sandstone; the outcroppingfiner-grained upper part is equivalent tomuch of the Bungil Formation in the Romaarea. The relation is complex and rathervariable (see PIs 2, 3). Where the GralloFormation pinches out the Gubberamundaand Mooga Sandstones cannot be differen­tiated, and together they make up most ofthe Hooray Sandstone. The outcroppingupper finer-grained part of the Hooray Sand­stone is approximately equivalent to theparalic Cadna-owie Formation which iswidespread subsurface in the EromangaBasin and extends for some distance sub­surface into the Surat Basin (see Exon &Senior, 1976).

The Hooray Sandstone was deposited bystreams which, on the evidence of isopachand limited palaeocurrent data, flowed to theeast and southeast. Sedimentation beganwith the deposition of coarse high-angled,cross-bedded sandstone, with little or nofines, probably by braided streams, but inthe north meandering streams predominatedlater and fine-grained overbank deposits arecommon. The detritus was probably derivedfrom both the south and north. In the souththe Cunnamulla Shelf was eroded in earlyHooray Sandstone time; after it was coveredthe sediment was derived solely from theCentral Western Fold Belt farther south. Thehigh content of recycled Late Permian andTriassic fossils in places (e.g. Evans, appen­dix 2 in Exon et al.. 1967) indicates thatsome of the sediment was derived from theolder Mesozoic and Palaeozoic sandstonesin the north. The presence of some glauconieand acritarchs in the outcropping upper partof the Hooray Sandstone suggests marineincursions, the effects of which are moreapparent in the Cadna-owie Formation.

Farther east into the basin larger quan­tities of fmes accumulated, and the largely

ing through Mitchell and Dirranbandi (Fig.23 ).

The sequence cropping out in the north­western part of the Surat Basin (Mollan etal., 1972) is about 120 m thick. It consistsmainly of sandstone, which ranges fromporous and quartzose to clayey and lithic;the main rock type is a white clayey eoarse­grained sublabile sandstone, containing scat­tered pebbles. The sandstone is generallymedium to thick-bedded, with abundanthigh-angled cross-bedding; some worm tubesare present. The sandstones are commonlyporous and consist of about 50 percentquartz, 15 percent fine-grained sediments.and 10 percent feldspar, set in a clay matrix.Some iron oxide, mica, zircon, and tour­maline may be present. Thick-bedded cross­stratified conglomerate is widespread. Itgenerally contains pebbles of quartz, acidvolcanies, chert, sediments and, less com­monly, fossil wood, set in a white sandstonematrix.

In the south near the Maranoa Anticline(Exon et al., 1967) the formation is finer­grained. Beds of white clayey siltstone andclaystone are common, especially in theupper part of the sequence. The uppersequence, which is about 50 m thick, con­sists essentially of thinly to thickly bedded,but rarely cross-bedded, very fine to fine­grained clayey sandstone, and laminated tothinly bedded white clayey siltstone. The silt­stone commonly contains plant remains andmicaceous partings. Below the upper se­quence is a poorly exposed siltstone se­quence, perhaps 30 m thick, consisting ofthinly bedded siltstone, fine-grained clayeysandstone, and white c1aystone. The lowerpart of the formation consists mainly of fine­grained sandstone.

Subsurface the Hooray Sandstone isthicker than in outcrop, and contains excel­lent aquifers that yield bicarbonate water.In the Amoseas Scalby No. I well (Hamilton.1966) the sequence consists chiefly of whiteto grey quartzose sandstone, of variablegrainsize, with a white clay matrix. Inter­beds of grey silty to sandy carbonaceousmudstone and grey argillaceous carbona­ceous siltstone are common, and there arealso few thin seams of coal.

IO?

The Hooray Sandstone generally overliesthe much finer-grained Westbourne Forma­tion with regional conformity, but local dis­conformities are not uncommon. In thesouth it overlaps the Westbourne Formationand rests directly on basement rocks. It isgenerally laterally equivalent to the Gub­beramunda Sandstone, Grallo Formation,and Mooga Sandstone; the outcroppingfiner-grained upper part is equivalent tomuch of the Bungil Formation in the Romaarea. The relation is complex and rathervariable (see PIs 2, 3). Where the GralloFormation pinches out the Gubberamundaand Mooga Sandstones cannot be differen­tiated, and together they make up most ofthe Hooray Sandstone. The outcroppingupper finer-grained part of the Hooray Sand­stone is approximately equivalent to theparalic Cadna-owie Formation which iswidespread subsurface in the EromangaBasin and extends for some distance sub­surface into the Surat Basin (see Exon &Senior, 1976).

The Hooray Sandstone was deposited bystreams which, on the evidence of isopachand limited palaeocurrent data, flowed to theeast and southeast. Sedimentation beganwith the deposition of coarse high-angled,cross-bedded sandstone, with little or nofines, probably by braided streams, but inthe north meandering streams predominatedlater and fine-grained overbank deposits arecommon. The detritus was probably derivedfrom both the south and north. In the souththe Cunnamulla Shelf was eroded in earlyHooray Sandstone time; after it was coveredthe sediment was derived solely from theCentral Western Fold Belt farther south. Thehigh content of recycled Late Permian andTriassic fossils in places (e.g. Evans, appen­dix 2 in Exon et al.. 1967) indicates thatsome of the sediment was derived from theolder Mesozoic and Palaeozoic sandstonesin the north. The presence of some glauconieand acritarchs in the outcropping upper partof the Hooray Sandstone suggests marineincursions, the effects of which are moreapparent in the Cadna-owie Formation.

Farther east into the basin larger quan­tities of fmes accumulated, and the largely

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TABLE 20. MARINE CRETACEOUS STRATIGRAPHYo00

MaximulIIName Thickness

(map symbol) (m)Lithology Fossils Environlllent of

DepositionRelations lvlajor

References

Middle toUpper(?)Albian

Lower toMiddleAlbian

UpperAptian

GrimanCreekFormation

(Klg)

SuralSiltstone

(IUs)

CoreenaMember(WallumbillaFm)

(Klc)

DoncasterMember(WallumbillaFm)

(KId)

480

150

210

270

Lithic sandstone thinlyinterbedded with siltstone,mudstone; same intrafor­mational conglomerateand coquinitic sandstone.Sandstone commonly cal­careous and glauconie­bearing

Lower part: thinly inter­bedded siltstone andmudstone with some thickmudstane beds; upperpart: thinly interbeddedsiltstone and fine sand­stone with some thicksandstone beds. Sandstonecommonly calcareous andglauconie-bearingSiltstone, mudstone, veryfine to fine labile andsublabilc sandstone,minor intraformationalconglomerate and co­quinite. Sandstone andsiltstone commonly cal­careous and glauconie­bearing

M udstone, carbonaceousin part, silts tone, tIne tovery fine labile to quart­zose sandstone. Calcar­eous concretions andglauconie at some levels

Marine and freshwater mol­luscs, plants, spores and pol­len of K2a division, somedinoflagellates

Marine mulluscs, benthonicforaminifera, spores and pol­len of Kld-K2a divisions,some dinoflagellates of lvl1lde­rongia tetracal1thalOdol1to­chitina operc1llata Zone, rareostracods

Marine molluscs, spores andpollen of Kld-K2a divisions,some benthonic foraminiferaand dinoflagellates, rareostracods

Marine molluscs, includingbelemnites, rare ammonites,and brachiopods, algal colon­ies, sponges, crinoids, ben­thonie foraminifera, sporeand pollen of Klb-c division,dinoflagellates of Dingodin­ium cerviculum Zone, rareostracods and fish teeth,wood

Marine regression:shallow marine, in­cluding beach de­position at first;terrestrial (stream)deposition later

Shallow marine:finer deposits laiddown below wavebase; coarser de­posits above wavebase

Marine regression:shallow marine in­cluding beaches, atfirst; coastal plaindeposition later

Shallow marine:above and belowwave base. Goodconnexion withopen sea at times

Conformably overliesSurat Sltst. Older inaxis of Mimosa Syn­cline than elsewhere,so Mimosa SynclineKlg is equivalent toKIg, Kls, and possiblypart of Klc on S partof Roma Shelf

Conformably overliesCoreena Mbr. Kls ofMimosa Syncline isequivalent to Kls andupper part of KIc onS part of Roma Shelf

Conformably overliesDoncaster Mbr. KIcof Mimosa Synclineis equivalent only tolower Klc on S partof Roma Shelf

Conformably overliesBungil Fm

Jenkins (1959,1960), Reiser(1970), Burger(1972 )

Reiser (1970),Burger (1972),Haig (1973)

Vine et a1.(1967), Day(1969), Burger(1972)

Vine & Day(1965), Day(1969), Burger(1972), Haig(1973 )

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TABLE 20. MARINE CRETACEOUS STRATIGRAPHYo00

MaximulIIName Thickness

(map symbol) (m)Lithology Fossils Environlllent of

DepositionRelations lvlajor

References

Middle toUpper(?)Albian

Lower toMiddleAlbian

UpperAptian

GrimanCreekFormation

(Klg)

SuralSiltstone

(IUs)

CoreenaMember(WallumbillaFm)

(Klc)

DoncasterMember(WallumbillaFm)

(KId)

480

150

210

270

Lithic sandstone thinlyinterbedded with siltstone,mudstone; same intrafor­mational conglomerateand coquinitic sandstone.Sandstone commonly cal­careous and glauconie­bearing

Lower part: thinly inter­bedded siltstone andmudstone with some thickmudstane beds; upperpart: thinly interbeddedsiltstone and fine sand­stone with some thicksandstone beds. Sandstonecommonly calcareous andglauconie-bearingSiltstone, mudstone, veryfine to fine labile andsublabilc sandstone,minor intraformationalconglomerate and co­quinite. Sandstone andsiltstone commonly cal­careous and glauconie­bearing

M udstone, carbonaceousin part, silts tone, tIne tovery fine labile to quart­zose sandstone. Calcar­eous concretions andglauconie at some levels

Marine and freshwater mol­luscs, plants, spores and pol­len of K2a division, somedinoflagellates

Marine mulluscs, benthonicforaminifera, spores and pol­len of Kld-K2a divisions,some dinoflagellates of lvl1lde­rongia tetracal1thalOdol1to­chitina operc1llata Zone, rareostracods

Marine molluscs, spores andpollen of Kld-K2a divisions,some benthonic foraminiferaand dinoflagellates, rareostracods

Marine molluscs, includingbelemnites, rare ammonites,and brachiopods, algal colon­ies, sponges, crinoids, ben­thonie foraminifera, sporeand pollen of Klb-c division,dinoflagellates of Dingodin­ium cerviculum Zone, rareostracods and fish teeth,wood

Marine regression:shallow marine, in­cluding beach de­position at first;terrestrial (stream)deposition later

Shallow marine:finer deposits laiddown below wavebase; coarser de­posits above wavebase

Marine regression:shallow marine in­cluding beaches, atfirst; coastal plaindeposition later

Shallow marine:above and belowwave base. Goodconnexion withopen sea at times

Conformably overliesSurat Sltst. Older inaxis of Mimosa Syn­cline than elsewhere,so Mimosa SynclineKlg is equivalent toKIg, Kls, and possiblypart of Klc on S partof Roma Shelf

Conformably overliesCoreena Mbr. Kls ofMimosa Syncline isequivalent to Kls andupper part of KIc onS part of Roma Shelf

Conformably overliesDoncaster Mbr. KIcof Mimosa Synclineis equivalent only tolower Klc on S partof Roma Shelf

Conformably overliesBungil Fm

Jenkins (1959,1960), Reiser(1970), Burger(1972 )

Reiser (1970),Burger (1972),Haig (1973)

Vine et a1.(1967), Day(1969), Burger(1972)

Vine & Day(1965), Day(1969), Burger(1972), Haig(1973 )

TABLE 20. MARINE CRETACEOUS STRATlGRAPHY-(cont.)

MaximumName Thickness

(map symbol) (m)Lithology Fossils Environment oj

DepositionRelations Major

Rejerences

Neocomianto LowerAptian

Bungil 270Formation

(Kly)

Labile to quartzose sand­stone. glauconie-bearingand calcareous in part,siltstone, mudstone, car­bonaceous in part, bio­turbidites

Marine and fresh-water mol­luscs, including belemnitesand brachiopods, arenaceousforaminifera, dinoflagellates,spores and pollen of Kla andKlb-c divisions, plants

Coastaltaic,shallowmarine

plain, del­shoreline.restricted

Conformably averliesMooga Ss!. Divisiblein Roma-Mitchell areainto four members

Exon & Vine(1970), Burger(1972, 1974)

LowerAptian

MinmiMember(BungilFm)

70 Fine to medium quart­zose to sublabile sand­stone, glauconie-bearingand calcareous in part,some siltstone, mUdstone,bioturbidites, and mudpebble conglomerate

Marine molluscs, includingbelemnites. freshwater mol­luscs, and brachiopods, aren­aceous foraminifera: raredinoflagellates but abundantother microplankton at somelevels, spores and pollen ofKla and Klb-c divisions,wood

Very shallowmarine and shore­line

Conformable withinBungil Fm; overliesNullawurt Sst Mbr

Day (1964;Appendix 1),Burger (1974)

Conformable withinBungil Fm; confinedto Merivale Synclinewhere it overlies Klkequivalents withinSouthlands FmConformable withinBungiJ Fm; conform­ably overlies MoogaSst in Roma area, in­cluded within South­lands Fm in MerivaleSyncline

Conformable

Neocomian

NullawurtSandstoneMember(Bungil Fm)

ClaravaleSandstoneMember(Bungil Fm)

KingullMember(Bungil Fm)

25

15

45

Well bedded very fine 10fine quartzose to sub­labile sandstone gradinginto siltstone. mUdstone,minor labile sandstoneand coarse quartzosesandstone. Glauconie to­wards top in MerivaleSyncline; equivalents inMimosa Syncline areglauconie-bearingCross-bedded fine tocoarse clayey quartzosesandstone, minor siltstoneand mudstane

Very fine to medium wellbedded clayey labile toquartzose sandstone, cal­careous and carbona­ceous in part, mudstone

Marine (in Merivale Synclineonly) and freshwater pele­cypods and gastropods, abun­dant microplankton at somelevels, worm burrows, ma­rine? plant roots, spores andpollen of Kla division, plantdebris

Wood and leaf remains,worm casts

Abundant microplankton atsome levels, spore and pollenof Kla division, plants, Unio

Shoreline andnear-shore non-marine

Stream depositionan coastal plain

Stream depositionon coastal plain;brackish lagoonal,estuarine, and del­taic environments

BungilKingullRoma,Mbr incline

withinFm; overlies

Mbr nearClaravale SstMerivaJe Syn-

Day (1964,1969), Burger(1974 )

Mollan et a1.(1972)

Day (1964),Burger (1974)

TABLE 20. MARINE CRETACEOUS STRATlGRAPHY-(cont.)

MaximumName Thickness

(map symbol) (m)Lithology Fossils Environment oj

DepositionRelations Major

Rejerences

Neocomianto LowerAptian

Bungil 270Formation

(Kly)

Labile to quartzose sand­stone. glauconie-bearingand calcareous in part,siltstone, mudstone, car­bonaceous in part, bio­turbidites

Marine and fresh-water mol­luscs, including belemnitesand brachiopods, arenaceousforaminifera, dinoflagellates,spores and pollen of Kla andKlb-c divisions, plants

Coastaltaic,shallowmarine

plain, del­shoreline.restricted

Conformably averliesMooga Ss!. Divisiblein Roma-Mitchell areainto four members

Exon & Vine(1970), Burger(1972, 1974)

LowerAptian

MinmiMember(BungilFm)

70 Fine to medium quart­zose to sublabile sand­stone, glauconie-bearingand calcareous in part,some siltstone, mudstone,bioturbidites, and mudpebble conglomerate

Marine molluscs, includingbelemnites. freshwater mol­luscs, and brachiopods, aren­aceous foraminifera: raredinoflagellates but abundantother microplankton at somelevels, spores and pollen ofKla and Klb-c divisions,wood

Very shallowmarine and shore­line

Conformable withinBungil Fm; overliesNullawurt Sst Mbr

Day (1964;Appendix 1),Burger (1974)

Conformable withinBungil Fm; confinedto Merivale Synclinewhere it overlies Klkequivalents withinSouthlands FmConformable withinBungiJ Fm; conform­ably overlies MoogaSst in Roma area, in­cluded within South­lands Fm in MerivaleSyncline

Conformable

Neocomian

NullawurtSandstoneMember(Bungil Fm)

ClaravaleSandstoneMember(Bungil Fm)

KingullMember(Bungil Fm)

25

15

45

Well bedded very fine 10fine quartzose to sub­labile sandstone gradinginto siltstone. mudstone,minor labile sandstoneand coarse quartzosesandstone. Glauconie to­wards top in MerivaleSyncline; equivalents inMimosa Syncline areglauconie-bearingCross-bedded fine tocoarse clayey quartzosesandstone, minor siltstoneand mudstane

Very fine to medium wellbedded clayey labile toquartzose sandstone, cal­careous and carbona­ceous in part, mudstone

Marine (in Merivale Synclineonly) and freshwater pele­cypods and gastropods, abun­dant microplankton at somelevels, worm burrows, ma­rine? plant roots, spores andpollen of Kla division, plantdebris

Wood and leaf remains,worm casts

Abundant microplankton atsome levels, spore and pollenof Kla division, plants, Unio

Shoreline andnear-shore non-marine

Stream depositionan coastal plain

Stream depositionon coastal plain;brackish lagoonal,estuarine, and del­taic environments

BungilKingullRoma,Mbr incline

withinFm; overlies

Mbr nearClaravale SstMerivaJe Syn-

Day (1964,1969), Burger(1974 )

Mollan et a1.(1972)

Day (1964),Burger (1974)

110

fine-grained Orallo Formation can be separ­ated, enabling subdivision of the equivalentsof the Hooray Sandstone into the typicalSurat Basin formations.

The thickness of the Hooray Sandstone isas shown in Figure 23. The thickness on theNebine Ridge is less than 150 m, but theformation thickens into the basin to as muchas 400 m in the Dirranbandi Syncline.

No plants have been identified, and nomarine macrofossils have been found. Evans(appendix 2 in Exon et al., 1967) has foundspores of Late Jurassic and Jurassic/Creta­ceous age in the formation. On stratigraphicgrounds its age is Late Jurassic to Early Cre­taceous-possibly as young as early Aptian.

Kumbarilla BedsThe Kumbarilla Beds were named and

defined by Exon & Vine (1970). The typearea is around Kumbarilla township, west ofDalby, where the outcrops consist of sand­stone, siltstone, and mudstone, with someconglomerate.

The beds crop out extensively in a meri­dional belt, extending from Miles to Yelar­bon in the eastern part of the basin. Theyare equivalent to the sequence from theSpringbok Sandstone to the Bungil Forma­tion, and these formations can still be recog­nized in the subsurface beneath and west ofthe Kumbarilla Beds.

White (1969) identified eight plant spe­cies from one locality, and three differentspecies 'from another locality in the upperpart of the Kumbarilla Beds.

Some of the equivalent formations arerecognizable in some of the outcrop areas.but the deep weathering and extensive soilcover made it impractieable to map thevarious formations separately.

Thus the Kumbarilla Beds are bestregarded as restricted to outcrop. They areshown on the surface geological map, but noton the various isopach maps, where the con­stituent formations have been identified.

DOMINANTLY MARINE LOWER CRETACEOUSSEQUENCE (Table 20)

Bungil FormationThe Bungil Formation was named and

defined by Exon & Vine (1970) and corres-

ponds to the Transition Beds of Whitehouse(1954). The type area is along BungilCreek north of Roma. It includes theKingull. Nullawurt Sandstone, and MinmiMembers of Day (1964), and the ClaravaleSandstone Member of Mollan et al. (1972).

In outcrop the Bungil Formation has beenmapped across the northern part of the basinand in the northeast; it has been included inthe Kumbarilla Beds in the southeast. Sub­surface it is widespread, but gives way in thewest to the Cadna-owie Formation of theEromanga Basin (see Exon & Senior, 1976).

The sequence consists mainly of fine­grained lithic sandstone, siltstone, and mud­stone, with subordinate sublabile andquartzose sandstones that grade into coarse­grained sandstone, especially in the typearea. Calcareous or glauconie-bearing bedsand concretions are common in the upperpart. The siltstone and mudstone are com­monly carbonaceous and contain plantremains. Bedding ranges from laminated inthe finer rock types to thickly cross-beddedin the coarser rocks. The formation yieldspoor supplies of fairly saline water in places.

Stratigraphic drilling (Gray, 1972; Exon,1972a) has shown that basin-wide it consistsof lithic sandstone, siltstone, and mudstonein about equal proportions; sub1abile andquartzose sandstones are present onlyaround the northern and eastern margins ofthe basin. The lithic sandstones from drillcores (Houston, 1972; Exon, 1972a) sel­dom contain over 40 percent quartz, andaround Surat 20 percent; other major con­stituents are feldspar, mainly potash feld­spar (10-20%), volcanic rock fragments(up to 70%), chlorite, glauconie pellets,calcite, and clay. The clay matrix and theglauconie have been shown by X-ray diffrac­tion to consist mainly of montmorillonite.Glauconie is concentrated in the upper halfof the formation.

In outcrop individual members can gener­ally be recognized, but widespread subsur­face correlations, although possible, are ofdubious validity. The members in the Romaarea have been discussed in detail by Day(1964) and Exon et al. (1967), and onlythe main features are discussed here.

110

fine-grained Orallo Formation can be separ­ated, enabling subdivision of the equivalentsof the Hooray Sandstone into the typicalSurat Basin formations.

The thickness of the Hooray Sandstone isas shown in Figure 23. The thickness on theNebine Ridge is less than 150 m, but theformation thickens into the basin to as muchas 400 m in the Dirranbandi Syncline.

No plants have been identified, and nomarine macrofossils have been found. Evans(appendix 2 in Exon et al., 1967) has foundspores of Late Jurassic and Jurassic/Creta­ceous age in the formation. On stratigraphicgrounds its age is Late Jurassic to Early Cre­taceous-possibly as young as early Aptian.

Kumbarilla BedsThe Kumbarilla Beds were named and

defined by Exon & Vine (1970). The typearea is around Kumbarilla township, west ofDalby, where the outcrops consist of sand­stone, siltstone, and mudstone, with someconglomerate.

The beds crop out extensively in a meri­dional belt, extending from Miles to Yelar­bon in the eastern part of the basin. Theyare equivalent to the sequence from theSpringbok Sandstone to the Bungil Forma­tion, and these formations can still be recog­nized in the subsurface beneath and west ofthe Kumbarilla Beds.

White (1969) identified eight plant spe­cies from one locality, and three differentspecies 'from another locality in the upperpart of the Kumbarilla Beds.

Some of the equivalent formations arerecognizable in some of the outcrop areas.but the deep weathering and extensive soilcover made it impractieable to map thevarious formations separately.

Thus the Kumbarilla Beds are bestregarded as restricted to outcrop. They areshown on the surface geological map, but noton the various isopach maps, where the con­stituent formations have been identified.

DOMINANTLY MARINE LOWER CRETACEOUSSEQUENCE (Table 20)

Bungil FormationThe Bungil Formation was named and

defined by Exon & Vine (1970) and corres-

ponds to the Transition Beds of Whitehouse(1954). The type area is along BungilCreek north of Roma. It includes theKingull. Nullawurt Sandstone, and MinmiMembers of Day (1964), and the ClaravaleSandstone Member of Mollan et al. (1972).

In outcrop the Bungil Formation has beenmapped across the northern part of the basinand in the northeast; it has been included inthe Kumbarilla Beds in the southeast. Sub­surface it is widespread, but gives way in thewest to the Cadna-owie Formation of theEromanga Basin (see Exon & Senior, 1976).

The sequence consists mainly of fine­grained lithic sandstone, siltstone, and mud­stone, with subordinate sublabile andquartzose sandstones that grade into coarse­grained sandstone, especially in the typearea. Calcareous or glauconie-bearing bedsand concretions are common in the upperpart. The siltstone and mudstone are com­monly carbonaceous and contain plantremains. Bedding ranges from laminated inthe finer rock types to thickly cross-beddedin the coarser rocks. The formation yieldspoor supplies of fairly saline water in places.

Stratigraphic drilling (Gray, 1972; Exon,1972a) has shown that basin-wide it consistsof lithic sandstone, siltstone, and mudstonein about equal proportions; sub1abile andquartzose sandstones are present onlyaround the northern and eastern margins ofthe basin. The lithic sandstones from drillcores (Houston, 1972; Exon, 1972a) sel­dom contain over 40 percent quartz, andaround Surat 20 percent; other major con­stituents are feldspar, mainly potash feld­spar (10-20%), volcanic rock fragments(up to 70%), chlorite, glauconie pellets,calcite, and clay. The clay matrix and theglauconie have been shown by X-ray diffrac­tion to consist mainly of montmorillonite.Glauconie is concentrated in the upper halfof the formation.

In outcrop individual members can gener­ally be recognized, but widespread subsur­face correlations, although possible, are ofdubious validity. The members in the Romaarea have been discussed in detail by Day(1964) and Exon et al. (1967), and onlythe main features are discussed here.

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Fig. 42. Well bedded trough cross-bedded calcareous labile sandstone (lower 7 m) and siltstone (upper3 m) of tbe Kingull Member overlain by 1 m of Nullawurt Sandstone. Immediately nortb of turn-off

to Nareeten from tbe Roma-Orallo road, 20 km northwest of Roma.

The Kingull Member, which crops outpoorly, consists of 30 to 50 m of carbona­ceous mudstone and muddy siltstone andsandstone. The sandstone ranges fromquartzose to labile and from fine to gritty,and is clayey or calcareous, or both. Wherenot calcareous it is very friable, probablyowing to leaching. It is characterized by theabundance of angular quartz grains, cross­bedding (Fig. 42), scour channels, lenseswith heavy-mineral accumulations, and con­centrations of calcium carbonate. In placesit is very well bedded (Figs 43, 44). Wellpreserved plant material is common in thefiner sediments. The member has beenmapped in a belt extending from south ofGunnewin to north of Yuleba.

The Claravale Sandstone Member is con­fined to the Mimosa Syncline, where it over-

lies the equivalent of the Kingull Member inthe Southlands Formation (Mollan et al.,1972). It consists of 10 to 30 m ofquartzose sandstone with a little siltstoneand mudstone. The sandstone ranges fromwhite to brown and is porous in outcrop. Inplaces it contains quartz pebbles and bandsof clay clasts. The rock is typically poorlybedded, and the thickness of the beds rangesfrom medium to very thick; small-scalecross-bedding is common. The sandstoneconsists mainly of quartz, a clay matrix, aconsiderable proportion of rock fragmentsand feldspar, and minor mica, iron oxide,tourmaline, rutile, and zircon. Wood impres­sions are common in the sandstone, and leaffragments in the finer beds.

The Nu/lawurt Sandstone Member is 20to 30 m thick, and generally overlies the

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Fig. 42. Well bedded trough cross-bedded calcareous labile sandstone (lower 7 m) and siltstone (upper3 m) of tbe Kingull Member overlain by 1 m of Nullawurt Sandstone. Immediately nortb of turn-off

to Nareeten from tbe Roma-Orallo road, 20 km northwest of Roma.

The Kingull Member, which crops outpoorly, consists of 30 to 50 m of carbona­ceous mudstone and muddy siltstone andsandstone. The sandstone ranges fromquartzose to labile and from fine to gritty,and is clayey or calcareous, or both. Wherenot calcareous it is very friable, probablyowing to leaching. It is characterized by theabundance of angular quartz grains, cross­bedding (Fig. 42), scour channels, lenseswith heavy-mineral accumulations, and con­centrations of calcium carbonate. In placesit is very well bedded (Figs 43, 44). Wellpreserved plant material is common in thefiner sediments. The member has beenmapped in a belt extending from south ofGunnewin to north of Yuleba.

The Claravale Sandstone Member is con­fined to the Mimosa Syncline, where it over-

lies the equivalent of the Kingull Member inthe Southlands Formation (Mollan et al.,1972). It consists of 10 to 30 m ofquartzose sandstone with a little siltstoneand mudstone. The sandstone ranges fromwhite to brown and is porous in outcrop. Inplaces it contains quartz pebbles and bandsof clay clasts. The rock is typically poorlybedded, and the thickness of the beds rangesfrom medium to very thick; small-scalecross-bedding is common. The sandstoneconsists mainly of quartz, a clay matrix, aconsiderable proportion of rock fragmentsand feldspar, and minor mica, iron oxide,tourmaline, rutile, and zircon. Wood impres­sions are common in the sandstone, and leaffragments in the finer beds.

The Nu/lawurt Sandstone Member is 20to 30 m thick, and generally overlies the

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Fig. 43. Well-bedded fine-grained sandstone in equivalent of the Kingull Member within the SouthlandsFormation. Cliff section north of 'Mountain View' track, 2 km east of where it joins the Mitchell­

Tooloombilla road, 47 km northeast of Mitchell.

KinguII Member, although in the MerivaleSyncline it rests on the Claravale SandstoneMember. The NulIawurt Sandstone Memberconsists mainly of white to buff, very wellsorted, very fine to fine-grained quartzose tosublabile sandstone, siltstone, and earbona­ceous mudstone, but both labile and coarselabile sandstone occur. Bedding is generalIythin to medium, and very regular with low­angled cross-bedding and ripple marks quitecommon. The sandstones consist mainly ofquartz and fragments of quartzite and fine­grained sedimentary rocks, with some claymatrix and a little feldspar, mica, and ironoxide, and rarc tourmaline, rutile, and zir­con. Plant roots occur at some localities andvertical worm burrows and tracks and trailsoccur at others. InfilIed desiccation crackshave also been observed (Fig. 45).

In the Merivale Syncline, where the litho­logyis similar, the sequence consists of weIIbedded fine-grained clayey quartzose sand­stone and siltstone, showing Iow-angledcross-bedding and ripple marks, but marinepelecypods and glauconie are abundant insome beds in the upper part.

The Nullawurt Sandstone Member hasbeen mapped westwards to the MaranoaRiver, and eastwards to north of WalIum­billa.

The Minmi Member consists of 20 to70 m of lithic to quartzose sandstone withsubordinate siltstone and mudstone. It restson the Nullawurt Sandstone Member. Thesandstone is in places calcareous and resist­ant, or leached and friable. It commonly con­tains glauconie, clayey rock fragments, fossilwood, and plagioclase, and a little mica and

112

Fig. 43. Well-bedded fine-grained sandstone in equivalent of the Kingull Member within the SouthlandsFormation. Cliff section north of 'Mountain View' track, 2 km east of where it joins the Mitchell­

Tooloombilla road, 47 km northeast of Mitchell.

KinguII Member, although in the MerivaleSyncline it rests on the Claravale SandstoneMember. The NulIawurt Sandstone Memberconsists mainly of white to buff, very wellsorted, very fine to fine-grained quartzose tosublabile sandstone, siltstone, and earbona­ceous mudstone, but both labile and coarselabile sandstone occur. Bedding is generalIythin to medium, and very regular with low­angled cross-bedding and ripple marks quitecommon. The sandstones consist mainly ofquartz and fragments of quartzite and fine­grained sedimentary rocks, with some claymatrix and a little feldspar, mica, and ironoxide, and rarc tourmaline, rutile, and zir­con. Plant roots occur at some localities andvertical worm burrows and tracks and trailsoccur at others. InfilIed desiccation crackshave also been observed (Fig. 45).

In the Merivale Syncline, where the litho­logyis similar, the sequence consists of weIIbedded fine-grained clayey quartzose sand­stone and siltstone, showing Iow-angledcross-bedding and ripple marks, but marinepelecypods and glauconie are abundant insome beds in the upper part.

The Nullawurt Sandstone Member hasbeen mapped westwards to the MaranoaRiver, and eastwards to north of WalIum­billa.

The Minmi Member consists of 20 to70 m of lithic to quartzose sandstone withsubordinate siltstone and mudstone. It restson the Nullawurt Sandstone Member. Thesandstone is in places calcareous and resist­ant, or leached and friable. It commonly con­tains glauconie, clayey rock fragments, fossilwood, and plagioclase, and a little mica and

113

Fig. 44. Ripple marks, cross-lamination, and carbonaceous partings in fine-grained labile sandstone ofthe equivalent of the Kingull Member. Same locality as Figure 43.

iron oxide in some beds. Sporadic pebblebands contain subangular pebbles of quartz,quartzite, cherty sediments, and acid andintermediate volcanics. Mud-pebble con­glomerates are characteristic in the Romaarea. The sandstone is thickly and poorlybedded, and strongly cross-stratified (bothlow and high-angled); interference and cur­rent ripple marks and worm burrows maybe present. The silts tone and mudstone arelaminated to thin-bedded, commonly car­bonaceous and micaceous, and in places richin glauconie. Stratigraphic drilling (Exon,1972a) has shown that extreme bioturbationwith intimate intermixing of siltstone andsandstone is a characteristic feature at somehorizons in places. Burrowing pclecypodsare common. and undoubtedlv caused muchof the bioturbation.

The Minmi Member has been mappedwestwards to the Maranoa River and east­wards to north of Yuleba.

The Bungil Formation rests conformablyon the Mooga Sandstone and SouthlandsFormation. In the western part of the basinit grades laterally into the upper part of theHooray Sandstone and the lower part of theDoncaster Member in outcrop, and theCadna-owie Formation in the subsurface. Inthe southeast the Bungil Formation is equi­valent to much of the Mooga Sandstone inthe centre of the basin (PIs 3, 5).

The formation consists of paralic sedi­ments with an increasing proportion ofmarine beds upwards. They are mainly cal­careous and lithic, but current and waveaclion resulted in the deposition of quartzosesand in places. Thc calcareous and poorly

113

Fig. 44. Ripple marks, cross-lamination, and carbonaceous partings in fine-grained labile sandstone ofthe equivalent of the Kingull Member. Same locality as Figure 43.

iron oxide in some beds. Sporadic pebblebands contain subangular pebbles of quartz,quartzite, cherty sediments, and acid andintermediate volcanics. Mud-pebble con­glomerates are characteristic in the Romaarea. The sandstone is thickly and poorlybedded, and strongly cross-stratified (bothlow and high-angled); interference and cur­rent ripple marks and worm burrows maybe present. The silts tone and mudstone arelaminated to thin-bedded, commonly car­bonaceous and micaceous, and in places richin glauconie. Stratigraphic drilling (Exon,1972a) has shown that extreme bioturbationwith intimate intermixing of siltstone andsandstone is a characteristic feature at somehorizons in places. Burrowing pclecypodsare common. and undoubtedlv caused muchof the bioturbation.

The Minmi Member has been mappedwestwards to the Maranoa River and east­wards to north of Yuleba.

The Bungil Formation rests conformablyon the Mooga Sandstone and SouthlandsFormation. In the western part of the basinit grades laterally into the upper part of theHooray Sandstone and the lower part of theDoncaster Member in outcrop, and theCadna-owie Formation in the subsurface. Inthe southeast the Bungil Formation is equi­valent to much of the Mooga Sandstone inthe centre of the basin (PIs 3, 5).

The formation consists of paralic sedi­ments with an increasing proportion ofmarine beds upwards. They are mainly cal­careous and lithic, but current and waveaclion resulted in the deposition of quartzosesand in places. Thc calcareous and poorly

114

Fig. 45. InfilIed desiccation cracks on underside of slab of very fine-grained basal NulIawurt Sandstone.The sandstone is quartzose, well sorted and medium-bedded. Ripple marks, vertical worm tubes and

animal tracks are associated features. Locality as for Figure 42.

sorted sediments of the Kingull Memberwere laid down by sluggish streams in andnear swamps, but the abundance of brackish­water microplankton in GSQ Roma No. 3(Burger, 1974) suggests close proximity tothe sea. The Claravale Sandstone was depo­sited by fairly fast-flowing streams that car­ried the fines farther south and east. Mostof the well sorted fine-grained sands tones inthe Nullawurt Sandstone Member, with theirgreat continuity and low-angled cross-bed­ding, are probably beach sands, although theycontain marine macrofossils only in the Meri­vale Syncline, where marine deposition pro­bably began. However, although all thequartzose sands were apparently sorted onand near beaches, some of them came to restin lagoons, bays, and estuaries. Some of thesands were vegetated and probably farmed

sheets of sand on land. The intervening cal­careous and labile sandstones and finer­grained sediments were probably lagoonal,and the vertical alternation of lithosomessuggests a fluctuating sea level. The macro­fauna in the Merivale Syncline consists ofboth marine and freshwater species, but inthe Roma area only freshwater species areknown (Day, 1969; Appendix I) . However,even in the Roma area Burger (1974) hasfound a large proportion of brackish micro­plankton in the Nullawurt Sandstone Mem­ber in BMR Roma No. 1 and DRD No. 27.

The Minmi Member contains abundantmarine macrofossils and has long beenregarded as shallow marine (see e.g. Day,1964). The quartzose sandstones with glau­conie probably represent beach sands orbars, and the bioturbated glauconie-rich

114

Fig. 45. InfilIed desiccation cracks on underside of slab of very fine-grained basal NulIawurt Sandstone.The sandstone is quartzose, well sorted and medium-bedded. Ripple marks, vertical worm tubes and

animal tracks are associated features. Locality as for Figure 42.

sorted sediments of the Kingull Memberwere laid down by sluggish streams in andnear swamps, but the abundance of brackish­water microplankton in GSQ Roma No. 3(Burger, 1974) suggests close proximity tothe sea. The Claravale Sandstone was depo­sited by fairly fast-flowing streams that car­ried the fines farther south and east. Mostof the well sorted fine-grained sands tones inthe Nullawurt Sandstone Member, with theirgreat continuity and low-angled cross-bed­ding, are probably beach sands, although theycontain marine macrofossils only in the Meri­vale Syncline, where marine deposition pro­bably began. However, although all thequartzose sands were apparently sorted onand near beaches, some of them came to restin lagoons, bays, and estuaries. Some of thesands were vegetated and probably farmed

sheets of sand on land. The intervening cal­careous and labile sandstones and finer­grained sediments were probably lagoonal,and the vertical alternation of lithosomessuggests a fluctuating sea level. The macro­fauna in the Merivale Syncline consists ofboth marine and freshwater species, but inthe Roma area only freshwater species areknown (Day, 1969; Appendix I) . However,even in the Roma area Burger (1974) hasfound a large proportion of brackish micro­plankton in the Nullawurt Sandstone Mem­ber in BMR Roma No. 1 and DRD No. 27.

The Minmi Member contains abundantmarine macrofossils and has long beenregarded as shallow marine (see e.g. Day,1964). The quartzose sandstones with glau­conie probably represent beach sands orbars, and the bioturbated glauconie-rich

sands, silts, and muds could have beenformed on mud flats, or in deeper water.Much of the member contains no macrofos­sils. Terpstra (1967) has identified a num­ber of arenaceous foraminifera in BMRMitchell No. 11. Burger (1974) has shownthat the proportion of brackish microplank­ton varies greatly, and that marine dino­flagellates are not very abundant, except inthe upper part of the member. Thus most ofthe sequence consists of brackish lagoonallithic sands and carbonaceous silts andmuds, over which the sea advanced andretreated from time to time. The macrofaunahas been transported and was probably'derived from a number of littoral and nearcoastal shallow water communities' (Day,Appendix 1).

Even where the members have not beenrecognized, similar transgressions and regres­sions must have taken place, giving rise to avaried suite of paralic sediments. Day( 1969) has noted the close similarity be­tween the Surat and Maryborough Basinfaunas in Bungil Formation time, and sug­gests that a seaway connected the two areas.Palaeotemperature data (Day, 1969) sug­gest a cool climate.

The thickness of the Bungil Formationranges from less than 100 m in the northand west to as much as 300 m in the south­east; this trend is even more marked than inthe thickness of the Bungil Formation/Don­caster Member interval as a whole (Fig.25).

Most of the plant species are long-ranging,but some of them have been assigned to theEarly Cretaceous (White, 1967a). TheNullawurt Sandstone Member contains atleast four species of marine macrofossils andis probably of Neocomian age (Day, 1969).The Minmi Member contains 20 species ofpelecypods (both burrowers and surfacedwellers), several gastropods, and onebelemnite, and is of early Aptian age (Day,1969; Appendix 1). The member also con­tains about 10 species of arenaceous fora­minifera (Crespin, 1960; Terpstra, 1967)of Early Cretaceous (probably Aptian) age.

The spores show that the lower part of theformation belongs to Evans' (1966) K 1a

-----------_....._- --~

115

division, and the upper part of the MinmiMember to his Kl b-c division, both of whichare of Early Cretaceous age (e.g. Burger,1974). Burger (1973) has formalized theK I a division as the M urospora {lorida Zone,which in the Roma area contains three sub­zones corresponding approximately to theMooga Sandstone, Kingull Member, andNullawurt Sandstone Member plus the lowerpart of the Minmi Member (Burger, 1974).

The age of the formation is thus, on fossilevidence, Neocomian to early Aptian.

Doncaster Member(WallumbiIla Formation)

The Doncaster Member of the WilgunyaFormation was named and defined by Vine& Day (1965), and was made a member ofthe Wallumbilla Formation by Vine et al.(1967). In the type area near Doncasterhomestead, 48 km north-northeast ofRichmond in the Eromanga Basin, it con­sists mainly of 'blue grey mudstone with sub­sidiary glauconitic mudstone and glauconiticsiltstone; the occurrence of beds rich in glau­conite is diagnostic of the unit' (Vine &Day, 1965). In the type area siltstone gradesinto very fine-grained sandstone.

The Doncaster Member crops out exten­sively across the northern part of the basinas far east as Miles. East and south of Milesoutcrops are rare and generally deeplyweathered. The member is everywhere iden­tifiable in the subsurface in the Surat Basin.

The best outcrops are in the Roma area,where they were studied by Day (1964),who followed Whitehouse's (1954) nomen­clature of 'Roma Formation'. Between Mor­ven and Jackson the member was mappedand described by Exon et al. (1967). Thefollowing description of the outcrops isbased mainly on the work of E. N. Milligan(Exonetal., 1967).

The lithology is similar to that in the typearea; the sequence consists mainly of mud­stone with subordinate siltstone and sand­stone. In outcrop in the Surat Basin themember is characterized by the interlamina­tion of fine and coarse mudstone. Glauconieis rarely seen in outcrop, but beds rich inglauconie occur sporadically in the shallowstratigraphic holes.

sands, silts, and muds could have beenformed on mud flats, or in deeper water.Much of the member contains no macrofos­sils. Terpstra (1967) has identified a num­ber of arenaceous foraminifera in BMRMitchell No. 11. Burger (1974) has shownthat the proportion of brackish microplank­ton varies greatly, and that marine dino­flagellates are not very abundant, except inthe upper part of the member. Thus most ofthe sequence consists of brackish lagoonallithic sands and carbonaceous silts andmuds, over which the sea advanced andretreated from time to time. The macrofaunahas been transported and was probably'derived from a number of littoral and nearcoastal shallow water communities' (Day,Appendix 1).

Even where the members have not beenrecognized, similar transgressions and regres­sions must have taken place, giving rise to avaried suite of paralic sediments. Day( 1969) has noted the close similarity be­tween the Surat and Maryborough Basinfaunas in Bungil Formation time, and sug­gests that a seaway connected the two areas.Palaeotemperature data (Day, 1969) sug­gest a cool climate.

The thickness of the Bungil Formationranges from less than 100 m in the northand west to as much as 300 m in the south­east; this trend is even more marked than inthe thickness of the Bungil Formation/Don­caster Member interval as a whole (Fig.25).

Most of the plant species are long-ranging,but some of them have been assigned to theEarly Cretaceous (White, 1967a). TheNullawurt Sandstone Member contains atleast four species of marine macrofossils andis probably of Neocomian age (Day, 1969).The Minmi Member contains 20 species ofpelecypods (both burrowers and surfacedwellers), several gastropods, and onebelemnite, and is of early Aptian age (Day,1969; Appendix 1). The member also con­tains about 10 species of arenaceous fora­minifera (Crespin, 1960; Terpstra, 1967)of Early Cretaceous (probably Aptian) age.

The spores show that the lower part of theformation belongs to Evans' (1966) K 1a

-----------_....._- --~

115

division, and the upper part of the MinmiMember to his Kl b-c division, both of whichare of Early Cretaceous age (e.g. Burger,1974). Burger (1973) has formalized theK I a division as the M urospora {lorida Zone,which in the Roma area contains three sub­zones corresponding approximately to theMooga Sandstone, Kingull Member, andNullawurt Sandstone Member plus the lowerpart of the Minmi Member (Burger, 1974).

The age of the formation is thus, on fossilevidence, Neocomian to early Aptian.

Doncaster Member(WallumbiIla Formation)

The Doncaster Member of the WilgunyaFormation was named and defined by Vine& Day (1965), and was made a member ofthe Wallumbilla Formation by Vine et al.(1967). In the type area near Doncasterhomestead, 48 km north-northeast ofRichmond in the Eromanga Basin, it con­sists mainly of 'blue grey mudstone with sub­sidiary glauconitic mudstone and glauconiticsiltstone; the occurrence of beds rich in glau­conite is diagnostic of the unit' (Vine &Day, 1965). In the type area siltstone gradesinto very fine-grained sandstone.

The Doncaster Member crops out exten­sively across the northern part of the basinas far east as Miles. East and south of Milesoutcrops are rare and generally deeplyweathered. The member is everywhere iden­tifiable in the subsurface in the Surat Basin.

The best outcrops are in the Roma area,where they were studied by Day (1964),who followed Whitehouse's (1954) nomen­clature of 'Roma Formation'. Between Mor­ven and Jackson the member was mappedand described by Exon et al. (1967). Thefollowing description of the outcrops isbased mainly on the work of E. N. Milligan(Exonetal., 1967).

The lithology is similar to that in the typearea; the sequence consists mainly of mud­stone with subordinate siltstone and sand­stone. In outcrop in the Surat Basin themember is characterized by the interlamina­tion of fine and coarse mudstone. Glauconieis rarely seen in outcrop, but beds rich inglauconie occur sporadically in the shallowstratigraphic holes.

116

The sequence also includes rare beds ofblack mudstone, fossiliferous and unfossili­ferous dark grey spherical limestone con­cretions, thin lenticular coquinite bands,algal stromatolites, lenses of coarse-grainedcalcareous quartzose sandstone, cone-in­cone limestone, gypsum, fibrous calcite, andsideritic calcite. The limestone concretionsand beds may be partly original and partlyweathering products, and the gypsum waspresumably formed as a result of theweathering of pyrite.

Information from wells shows that themember near outcrop is about 100 m thick.In outcrop it is difficult to establish a reliablecomposite because of poor exposures, lowregional dip, and minor faulting. However,the following three units (from top to bot­tom) have been recognized:

Unit 3. Mudstone interbedded with silt­stone beds up to 2 m thick. Thinly interbed­ded mudstone and siltstone/fine sandstonesequences are present in some areas (e.g.Clerk Creek at its junction with Bungewor­gorai Creek). The concretions are oblate­ovoid or coalesced to form distinct beds;they are rarely fossiliferous. Fossils are fewin number and type and include rare pelagicbelemnites. Small lenses of mudstonepebbles (and rarely fossils), woody material,fibrous calcite, and cone-in-cone limestoneare common.

Unit 2. A uniform succession of massivemudstone. Most of the concretions are darkgrey, spherical, and poorly fossiliferous. Thefossils consist mainly of Cyrenopsis sp. andburrowers (Panopea sp., etc.).

Unit 1. Mudstone with rare lenses of cal­careous quartzose sandstone. Thin lenses ofsiltstone and coquinite are common, andalgal colonies are present near the base ofthe sequence. The concretions are generallylarge and oblate, and incorporate lenses ofsiltstone and coquinite, and rarely fossil logs;some of the concretions are small and irre­gular. The rich fauna is characterized bysessile forms such as brachiopods, entirecrinoids, sponges, and oysters, and by apelagic element comprising belemnites andrare ammonites.

Unit 1 is roughly equivalent to the 'Puri­siphonia horizon' of Day (1964, p. 17). Ithas been traced in outcrop for 250 km fromnorth of Mitchell to north of Drillham. Unit2 is the probable equivalent of the 'abundantCyrenopsis horizon' of Day (1964, p. 17;appendix 1 in Exon et al., 1967).

Stratigraphic drilling (e.g. Exon et al.,1967; Gray, 1972) and petroleum explora­tion wells have shown that the member con­sists mainly of mudstone, with abundant silt­stone and relatively minor sandstone. Thestratigraphic drilling suggests that there aretwo sequences of basinwide extent: an uppermudstone-siltstone sequence correspondingto unit 3 in outcrop, and a lower mudstonesubdivision corresponding to unit 2.

The Doncaster Member conformablyoverlies the Bungil Formation in most of thebasin. In outcrop west of the Maranoa Anti­cline it is not seen in contact with an under­lying unit, but in BMR Mitchell No. 7 theDoncaster Member rests directly on yellow­brown weathered Hooray Sandstone. Farthersouth, in the SUbsurface, it overlies theCadna-owie Formation. The outcroppingDoncaster Member in the west containssome rock types typical of the Minmi Mem­ber, and it is possible that it grades graduallyeastward into the Bungil Formation. Thelower part of the Doncaster Member wouldthen be an offshore facies of the MinmiMember. The member weathers to soft greymudstone, then to a light grey clay, andfinally to a 'black soil' that distinguishes itfrom the overlying Coreena Member and theunderlying Minmi Member which weather tobrown soils.

The environment of deposition around themargin of the basin is revealed by the out­crop sequence. The presence of winnoweddeposits (coquinites, and coarse quartzosesandstone lenses) and scour-and-fill andcross-lamination structures indicates thatthere was periodic strong current or waveaction during the deposition of unit 1. How­ever, the supply of coarse sediment was lessthan when the Minmi Member was laiddown, and the main sediment being depo­sited was mud. Strong currents brought apelagic fauna into the area. The abundance

116

The sequence also includes rare beds ofblack mudstone, fossiliferous and unfossili­ferous dark grey spherical limestone con­cretions, thin lenticular coquinite bands,algal stromatolites, lenses of coarse-grainedcalcareous quartzose sandstone, cone-in­cone limestone, gypsum, fibrous calcite, andsideritic calcite. The limestone concretionsand beds may be partly original and partlyweathering products, and the gypsum waspresumably formed as a result of theweathering of pyrite.

Information from wells shows that themember near outcrop is about 100 m thick.In outcrop it is difficult to establish a reliablecomposite because of poor exposures, lowregional dip, and minor faulting. However,the following three units (from top to bot­tom) have been recognized:

Unit 3. Mudstone interbedded with silt­stone beds up to 2 m thick. Thinly interbed­ded mudstone and siltstone/fine sandstonesequences are present in some areas (e.g.Clerk Creek at its junction with Bungewor­gorai Creek). The concretions are oblate­ovoid or coalesced to form distinct beds;they are rarely fossiliferous. Fossils are fewin number and type and include rare pelagicbelemnites. Small lenses of mudstonepebbles (and rarely fossils), woody material,fibrous calcite, and cone-in-cone limestoneare common.

Unit 2. A uniform succession of massivemudstone. Most of the concretions are darkgrey, spherical, and poorly fossiliferous. Thefossils consist mainly of Cyrenopsis sp. andburrowers (Panopea sp., etc.).

Unit 1. Mudstone with rare lenses of cal­careous quartzose sandstone. Thin lenses ofsiltstone and coquinite are common, andalgal colonies are present near the base ofthe sequence. The concretions are generallylarge and oblate, and incorporate lenses ofsiltstone and coquinite, and rarely fossil logs;some of the concretions are small and irre­gular. The rich fauna is characterized bysessile forms such as brachiopods, entirecrinoids, sponges, and oysters, and by apelagic element comprising belemnites andrare ammonites.

Unit 1 is roughly equivalent to the 'Puri­siphonia horizon' of Day (1964, p. 17). Ithas been traced in outcrop for 250 km fromnorth of Mitchell to north of Drillham. Unit2 is the probable equivalent of the 'abundantCyrenopsis horizon' of Day (1964, p. 17;appendix 1 in Exon et al., 1967).

Stratigraphic drilling (e.g. Exon et al.,1967; Gray, 1972) and petroleum explora­tion wells have shown that the member con­sists mainly of mudstone, with abundant silt­stone and relatively minor sandstone. Thestratigraphic drilling suggests that there aretwo sequences of basinwide extent: an uppermudstone-siltstone sequence correspondingto unit 3 in outcrop, and a lower mudstonesubdivision corresponding to unit 2.

The Doncaster Member conformablyoverlies the Bungil Formation in most of thebasin. In outcrop west of the Maranoa Anti­cline it is not seen in contact with an under­lying unit, but in BMR Mitchell No. 7 theDoncaster Member rests directly on yellow­brown weathered Hooray Sandstone. Farthersouth, in the SUbsurface, it overlies theCadna-owie Formation. The outcroppingDoncaster Member in the west containssome rock types typical of the Minmi Mem­ber, and it is possible that it grades graduallyeastward into the Bungil Formation. Thelower part of the Doncaster Member wouldthen be an offshore facies of the MinmiMember. The member weathers to soft greymudstone, then to a light grey clay, andfinally to a 'black soil' that distinguishes itfrom the overlying Coreena Member and theunderlying Minmi Member which weather tobrown soils.

The environment of deposition around themargin of the basin is revealed by the out­crop sequence. The presence of winnoweddeposits (coquinites, and coarse quartzosesandstone lenses) and scour-and-fill andcross-lamination structures indicates thatthere was periodic strong current or waveaction during the deposition of unit 1. How­ever, the supply of coarse sediment was lessthan when the Minmi Member was laiddown, and the main sediment being depo­sited was mud. Strong currents brought apelagic fauna into the area. The abundance

of sessile forms indicates that a stable sub­strate existed nearby, perhaps as semi-con­solidated sands in the Minmi Member, or asaccumulations of bioclastic material toocoarse for the currents to shift. Some of thecalcareous concretions are encrusted by ser­pulid colonies, which suggests that theyformed during deposition, thus providinglocal hard bottom. Locally, littoral condi­tions allowed algal colonies to form, butmost of the sediments were probably depo­sited below normal wave base. Sand wascarried in during exceptional storms.

Unit 2 was apparently laid down in arestricted deeper-water environment, wheremud formed the substrate for a number ofburrowing pelecypods.

The conditions prevailing during the finalstage of deposition (unit 3) are transitionalto those of the Coreena Member. Currentaction was stronger and brought in coarsersediment and a significant pelagic element.Some of the regularly interbedded sedimentsmay well have been laid down in deltas withannual alternation of fine and coarse sedi­ment.

For the basin as a whole it seems that arapid transgression occurred and deeper­water muds (unit 2) were deposited directlyon the brackish-water sediments of the Bun­gil Formation farther into the basin, whereasaround the margin of the basin the transi­tional sediments of unit 1 were laid downfirst. The depression continued to fill rapidly(see Fig. 25) and when the sea level fellagain, shallow-water sediments (unit 3)were deposited across the whole basin.

Day (1964, p. 17) remarked that 'Thedetailed distribution of the fossils is ratherpuzzling; they are frequently abundant inonly one bed of an exposure, while adjacentlithologically identical beds are quite bar­ren.' This could be explained by the forma­tion of a periodic density barrier in thewaters of a restricted epicontinental sea,between an upper layer of relatively freshwater and a lower layer of relatively saltywater, similar to that found in the Baltic Sea(Exon, 1972b). Below such a barrier reduc­ing conditions prevail, and the calcareousfauna is dissolved in the bottom muds soon

117

after death; in the Baltic Sea only arena­ceous foraminifera are preserved under theseconditions. Periodic increases in the inflowof salt water, possibly as a result of storms,or of subsidence in the straits area, destroysthe density barrier and the reducing condi­tions, and in these circumstances the cal­careous organisms are preserved. Undersuch conditions there would be little differ­ence in the bulk lithology of the fossiliferousand non-fossiliferous sediments.

That reducing conditions prevailed duringthe deposition of the Doncaster Member isconfirmed by the abundance of carbona­ceous material and glauconie. Crespin(1960) and Haig (1973) have shown thatthe ratio of species of arenaceous fora­minifera to calcareous foraminifera variesconsiderably, and that arenaceous formsalone are present in some beds (see Fig.46). This suggests that the calcareous formswere dissolved when reducing conditionsprevailed.

The Doncaster Member is thickest in themiddle of the basin, but the variation inthickness only ranges from 100 to 150 m.The thinness of the sequence in north andsouth suggests that there may have beenseaways to the west and east. Day (1969)has suggested that the Surat Basin was con­nected to the open sea both to the west, viathe Eromanga and Carpentaria Basins, and tothe east, via the Maryborough Basin. Theeasterly connexion was possibly via the Mul­gildie Rift or the Moreton Basin. As inBungil Formation time the climate appearsto have been cool (Day, 1969).

The Doncaster Member contains theRoma shelly fauna (see Vine et al., 1967)that was first described by Whitehouse(1925), and which contains about 40 spe­cies (Day, 1969). It is dominated by pele­cypods, but gastropods, belemnites, brachia­pods, crinoids, and sponges are abundant atsome horizons, and ammonites have alsobeen found. The age of the fauna is lateAptian (Day, 1969).

Crespin (1960) and Terpstra (1969)recorded the presence of foraminifera in themember, and Haig (1973) has identifiedabout 40 species belonging to three faunas,which he regards as Aptian.

of sessile forms indicates that a stable sub­strate existed nearby, perhaps as semi-con­solidated sands in the Minmi Member, or asaccumulations of bioclastic material toocoarse for the currents to shift. Some of thecalcareous concretions are encrusted by ser­pulid colonies, which suggests that theyformed during deposition, thus providinglocal hard bottom. Locally, littoral condi­tions allowed algal colonies to form, butmost of the sediments were probably depo­sited below normal wave base. Sand wascarried in during exceptional storms.

Unit 2 was apparently laid down in arestricted deeper-water environment, wheremud formed the substrate for a number ofburrowing pelecypods.

The conditions prevailing during the finalstage of deposition (unit 3) are transitionalto those of the Coreena Member. Currentaction was stronger and brought in coarsersediment and a significant pelagic element.Some of the regularly interbedded sedimentsmay well have been laid down in deltas withannual alternation of fine and coarse sedi­ment.

For the basin as a whole it seems that arapid transgression occurred and deeper­water muds (unit 2) were deposited directlyon the brackish-water sediments of the Bun­gil Formation farther into the basin, whereasaround the margin of the basin the transi­tional sediments of unit 1 were laid downfirst. The depression continued to fill rapidly(see Fig. 25) and when the sea level fellagain, shallow-water sediments (unit 3)were deposited across the whole basin.

Day (1964, p. 17) remarked that 'Thedetailed distribution of the fossils is ratherpuzzling; they are frequently abundant inonly one bed of an exposure, while adjacentlithologically identical beds are quite bar­ren.' This could be explained by the forma­tion of a periodic density barrier in thewaters of a restricted epicontinental sea,between an upper layer of relatively freshwater and a lower layer of relatively saltywater, similar to that found in the Baltic Sea(Exon, 1972b). Below such a barrier reduc­ing conditions prevail, and the calcareousfauna is dissolved in the bottom muds soon

117

after death; in the Baltic Sea only arena­ceous foraminifera are preserved under theseconditions. Periodic increases in the inflowof salt water, possibly as a result of storms,or of subsidence in the straits area, destroysthe density barrier and the reducing condi­tions, and in these circumstances the cal­careous organisms are preserved. Undersuch conditions there would be little differ­ence in the bulk lithology of the fossiliferousand non-fossiliferous sediments.

That reducing conditions prevailed duringthe deposition of the Doncaster Member isconfirmed by the abundance of carbona­ceous material and glauconie. Crespin(1960) and Haig (1973) have shown thatthe ratio of species of arenaceous fora­minifera to calcareous foraminifera variesconsiderably, and that arenaceous formsalone are present in some beds (see Fig.46). This suggests that the calcareous formswere dissolved when reducing conditionsprevailed.

The Doncaster Member is thickest in themiddle of the basin, but the variation inthickness only ranges from 100 to 150 m.The thinness of the sequence in north andsouth suggests that there may have beenseaways to the west and east. Day (1969)has suggested that the Surat Basin was con­nected to the open sea both to the west, viathe Eromanga and Carpentaria Basins, and tothe east, via the Maryborough Basin. Theeasterly connexion was possibly via the Mul­gildie Rift or the Moreton Basin. As inBungil Formation time the climate appearsto have been cool (Day, 1969).

The Doncaster Member contains theRoma shelly fauna (see Vine et al., 1967)that was first described by Whitehouse(1925), and which contains about 40 spe­cies (Day, 1969). It is dominated by pele­cypods, but gastropods, belemnites, brachia­pods, crinoids, and sponges are abundant atsome horizons, and ammonites have alsobeen found. The age of the fauna is lateAptian (Day, 1969).

Crespin (1960) and Terpstra (1969)recorded the presence of foraminifera in themember, and Haig (1973) has identifiedabout 40 species belonging to three faunas,which he regards as Aptian.

\·-·~.Surat

/ Siltstone

....e

_.

+ •

+

DoncasterMember

CoreenaMember

Gsa Surat 1 after Terpsrra 119691

Ground level

1510

Calcareous

-.I

Number of species10 0 5

Arenaceous

4

GSQ Surat 3-Haig (1973)GSQ Surat 1-Haig (1973)Outcrop-Crespin (1960)DRD27-Haig (1973)GSQ Surat 1-Terpstra (1969)Strong evidence of solution of calcareousforms (arenaceous» calcareous)

•

Griman Creek Formation

Coreena Member (GSO Surat 1)Haig (1973)

Surat Siltstone (GSO Surat 3)Haig (1973)

Doncaster Member (GSO Surat 1)Haig (1973)

x

+ 0

• •+ 0+ •

~

118

Arenaceous Calcareous

Minmi Member (DRD 27)

TO

•I•

Crespin (1960)(outcrop)

5 0 5 10Number of species

Q/A/595

Fig. 46. Distribution of Cretaceous foraminifera.

\·-·~.Surat

/ Siltstone

....e

_.

+ •

+

DoncasterMember

CoreenaMember

Gsa Surat 1 after Terpsrra 119691

Ground level

1510

Calcareous

-.I

Number of species10 0 5

Arenaceous

4

GSQ Surat 3-Haig (1973)GSQ Surat 1-Haig (1973)Outcrop-Crespin (1960)DRD27-Haig (1973)GSQ Surat 1-Terpstra (1969)Strong evidence of solution of calcareousforms (arenaceous» calcareous)

•

Griman Creek Formation

Coreena Member (GSO Surat 1)Haig (1973)

Surat Siltstone (GSO Surat 3)Haig (1973)

Doncaster Member (GSO Surat 1)Haig (1973)

x

+ 0

• •+ 0+ •

~

118

Arenaceous Calcareous

Minmi Member (DRD 27)

TO

•I•

Crespin (1960)(outcrop)

5 0 5 10Number of species

Q/A/595

Fig. 46. Distribution of Cretaceous foraminifera.

Burger (1968, 1974) has studied thepalynology of the member, which belongs toEvans' (1966) spore division K1b-c ofAptian age. Acritarchs, and the dinoflagel­lates Odontochitina operculata, Muderongiatetracantha, and Dingodinium cerviculumare abundant at some horizons.

The late Aptian age of the memberdepends on the macrofossils, and in parti­cular on the ammonites, which Day (1969,p. 158) says 'offer good evidence for inter­continental correlation' despite some diffi­culties.

Coreena Member(Wallumbilla Formation)

The Coreena Member was named anddefined as a member of the WallurnbillaFormation by Vine et al. ( 1967). It isnamed after Coreena station, some 32 kmnortheast of Barcaldine in the EromangaBasin. In the type area it consists of inter­bedded siltstone, which grades into labileand sublabile sandstone, and mudstone.Some beds contain glauconie. Coquinitesand intraformational conglomerate arelocally important.

It crops out virtually continuously fromthe type area to the Surat Basin, where theoutcrops form a discontinuous zone acrossthe northern part of the basin from south ofMorven to Miles. Deep weathering is wide­spread, and the member commonly formsmesas. It is widespread in the subsurface inthe Eromanga and Surat Basins.

In outcrop in the Surat Basin (Exon etal., 1967) siltstone predominates over mud­stone, and as in the type area, calcareousconcretionary beds, glauconie, coquinites,intraformational conglomerates, and cross­lamination are common in places. Some ofthe intraformational conglomerates near thebase of the member contain reworkedAptian fossils as well as Albian fossils.

The shallow stratigraphic holes in variousparts of the sequence have shown that nearAmby (BMR Mitchell No. 10; Exon et al.,1967) it consists mainly of siltstone, southof Roma (BMR Roma No. 9; Exon, 1972a)of tough grey mudstone grading into silt­stone, and near Surat (GSQ Surat No. 1;Gray, 1972) of siltstone, labile sandstone,

119

intraformational conglomerate, and minorcoal. Throughout the basin the petroleumexploration wells penetrated a silty sequencethat commonly contains a little coal.

Examination of cores from the Surat area(Houston, 1972) has shown that the sand­stones are lithic; they contain about 30 per­cent volcanic lithic grains, 15 percent feld­spar, and 10 percent quartz, a clay matrix,cement, and pore space. Common cementsare calcite and siderite; chlorite, mica, andglauconie are also present. The porosity(Gray, 1972) averages 29 percent.

The Coreena Member overlies the Don­caster Member with regional conformity, butthe presence of reworked Doncaster fossilswithin the Coreena Member shows that thecontact is erosional in places.

The Coreena Member was laid down dur­ing a regression, and the presence of intra­formational conglomerate, coquinites, glau­conie-rich siltstone, carbonaceous mudstone,and coal attests to local variability in timeand space. The environment ranged fromshallow open marine to coastal mud flats,lagoons, and swamps. Day (1969) has sug­gested that the area was open to the sea inthe west, but that the eastern seaway hadbeen closed; he also gave evidence for a cooltemperate climate.

The member is generally about 100 mthick, but thins to less than 50 m in the west,and thickens to over 150 m in the east (PIs3, 5).

An impoverished Albian macrofauna hasbeen recorded in the Surat Basin. It con­sists of ten species of shelly macrofossils andincludes the two belemnites Peratobelus sel­heimi? and Dimitobellls diptychlls (Day,1969; Appendix 1). Peratobelus selheimi?is believed to be an Aptian form, and wasapparently derived from the DoncasterMember. Foraminifera are rare, althoughTerpstra (1969) identified three calcareousand one arenaceous species in BMR RomaNo. 9. The ostracods found in one core inBMR Surat No. 1 suggest a middle Albianage by correlation with Germany (Jones,1968) .

The plant remains present have nof beenidentified. Microplankton and dinoflagellates

Burger (1968, 1974) has studied thepalynology of the member, which belongs toEvans' (1966) spore division K1b-c ofAptian age. Acritarchs, and the dinoflagel­lates Odontochitina operculata, Muderongiatetracantha, and Dingodinium cerviculumare abundant at some horizons.

The late Aptian age of the memberdepends on the macrofossils, and in parti­cular on the ammonites, which Day (1969,p. 158) says 'offer good evidence for inter­continental correlation' despite some diffi­culties.

Coreena Member(Wallumbilla Formation)

The Coreena Member was named anddefined as a member of the WallurnbillaFormation by Vine et al. ( 1967). It isnamed after Coreena station, some 32 kmnortheast of Barcaldine in the EromangaBasin. In the type area it consists of inter­bedded siltstone, which grades into labileand sublabile sandstone, and mudstone.Some beds contain glauconie. Coquinitesand intraformational conglomerate arelocally important.

It crops out virtually continuously fromthe type area to the Surat Basin, where theoutcrops form a discontinuous zone acrossthe northern part of the basin from south ofMorven to Miles. Deep weathering is wide­spread, and the member commonly formsmesas. It is widespread in the subsurface inthe Eromanga and Surat Basins.

In outcrop in the Surat Basin (Exon etal., 1967) siltstone predominates over mud­stone, and as in the type area, calcareousconcretionary beds, glauconie, coquinites,intraformational conglomerates, and cross­lamination are common in places. Some ofthe intraformational conglomerates near thebase of the member contain reworkedAptian fossils as well as Albian fossils.

The shallow stratigraphic holes in variousparts of the sequence have shown that nearAmby (BMR Mitchell No. 10; Exon et al.,1967) it consists mainly of siltstone, southof Roma (BMR Roma No. 9; Exon, 1972a)of tough grey mudstone grading into silt­stone, and near Surat (GSQ Surat No. 1;Gray, 1972) of siltstone, labile sandstone,

119

intraformational conglomerate, and minorcoal. Throughout the basin the petroleumexploration wells penetrated a silty sequencethat commonly contains a little coal.

Examination of cores from the Surat area(Houston, 1972) has shown that the sand­stones are lithic; they contain about 30 per­cent volcanic lithic grains, 15 percent feld­spar, and 10 percent quartz, a clay matrix,cement, and pore space. Common cementsare calcite and siderite; chlorite, mica, andglauconie are also present. The porosity(Gray, 1972) averages 29 percent.

The Coreena Member overlies the Don­caster Member with regional conformity, butthe presence of reworked Doncaster fossilswithin the Coreena Member shows that thecontact is erosional in places.

The Coreena Member was laid down dur­ing a regression, and the presence of intra­formational conglomerate, coquinites, glau­conie-rich siltstone, carbonaceous mudstone,and coal attests to local variability in timeand space. The environment ranged fromshallow open marine to coastal mud flats,lagoons, and swamps. Day (1969) has sug­gested that the area was open to the sea inthe west, but that the eastern seaway hadbeen closed; he also gave evidence for a cooltemperate climate.

The member is generally about 100 mthick, but thins to less than 50 m in the west,and thickens to over 150 m in the east (PIs3, 5).

An impoverished Albian macrofauna hasbeen recorded in the Surat Basin. It con­sists of ten species of shelly macrofossils andincludes the two belemnites Peratobelus sel­heimi? and Dimitobellls diptychlls (Day,1969; Appendix 1). Peratobelus selheimi?is believed to be an Aptian form, and wasapparently derived from the DoncasterMember. Foraminifera are rare, althoughTerpstra (1969) identified three calcareousand one arenaceous species in BMR RomaNo. 9. The ostracods found in one core inBMR Surat No. 1 suggest a middle Albianage by correlation with Germany (Jones,1968) .

The plant remains present have nof beenidentified. Microplankton and dinoflagellates

120

are relatively uncommon (D. Burger, pers.comm.), and rare ostracods have beenreported (e.g. Terpstra, 1968). The sporesgenerally fall within Evans' (1966) divisionKId (e.g. Burger, 1972) which is of earlyAlbian age, but the occasional presence ofdivision K2a suggests that the memberranges into the Middle Albian.

Surat SiltstoneThe Surat SiItstone, named after Surat

township, and defined by Reiser (1970), isconfined to the Surat Basin. The type sectionis continuous core in GSQ Surat No. 1 in theinterval from 50 to 460 feet (15-140 m);it consists of interbedded siltstone and mud­stone.

The formation crops out very poorlyindeed, and has only been identified in scat­tered outcrops in the western part of thebasin. North of Surat its position is markedby a broad band of Cainozoic alluvium alongthe Balonne River. In the east it probablycrops out in a few places, but has not beenidentified. It is present in the subsurfacethroughout the central part of the basin andalmost all our knowledge is based on welland water-bore data.

The sequence consists mainly of thinlyinterbedded siltstone and mudstone, withnumerous sandstone lenses at some levels. Inthe type section the basal fifth consistsmainly of mudstone, and the remainder pre­dominantly of siltstone. The mudstone isgenerally carbonaceous and commonly pyri­dc; the siltstone is grey to black, and con­tains carbonaceous plant remains and mica;the sandstone is fine to very fine-grained,lithic, and commonly contains glauconie andrare red grains presumed to be garnet. Exa­mination of cores from near Surat (Houston,1972) has shown that the sandstone andsiltstone contain 30 to 60 percent lithicgrains, 10 to 20 percent quartz, 10 to 20percent feldspar, and abundant glauconie,chlorite, and calcite. In the eastern part ofthe basin lithic sandstone is more important,and forms half the upper 50 m of thesequence in BMR Dalby No. 2; it is generallyvery fine to fine-grained, but medium­grained beds occur. Exon (I 972a) recordedabout 30 percent clay matrix and up to 50

percent carbonaceous debris in the sand­stone in the east, where high-angled cross­bedding is fairly common.

The Surat Siltstone rests conformably onthe thicker-bedded and somewhat coarser­grained Coreena Member. This boundary iswell defined on the electrical logs of petro­leum exploration wells, but is difficult toidentify on the gamma-ray logs of water­bores. The member's relation to theEromanga Basin sequence, with which itmay not be in lateral continuity, is not clear.A natural lithological correlate is the upperAlbian Allaru Mudstone, but palaeonto­logical evidence suggests that the Surat Silt­stone is older, and a correlate of the upperpart of the Coreena Member and the Toole­buc Limestone in the Eromanga Basin.

The formation is predominantly shallowmarine, although plant roots occur high inthe sequence in BMR Dalby No. 2 (Exon,1972a). The presence of abundant foramini­fera (Haig, 1973) and small shelly fossils(e.g. Gray, 1972, p. 45) at some levels indi­cates full marine, or almost full marine, con­ditions; the scarcity of dinoflagellates andother microplankton (Burger, 1972; & pers.comm.) suggests a shallow-water environ­ment. Glauconie is also assumed to indicatemarine conditions. Thus the organisms andthe fine-grained thinly bedded nature of thesediments suggest that the beds were laiddown in a shallow sea, mainly on tidal flatsand in protected bays. The carbonaceousmudstones may have been laid down incoastal swamps, and the cross-bedded sand­stones in stream and tidal channels. Com­pared with the Coreena Member there is ahigher proportion of marine beds.

The thickness of the member ranges fromgenerally 100 to 130 m.

The plant remains and small shelly fossilshave not yet been identified. Benthonic fora­minifera are abundant in GSQ Surat Nos. 1and 3 (Haig, 1973) with up to 16 calcar­eous and 9 arenaceous species in a singlesample (see Fig. 46); the foraminifera sug­gest correlation with the lower to middleAlbian Coreena Member in the EromangaBasin. Spores of Evans' (1966) divisionsKId and K2a, of Albian age, are present in

120

are relatively uncommon (D. Burger, pers.comm.), and rare ostracods have beenreported (e.g. Terpstra, 1968). The sporesgenerally fall within Evans' (1966) divisionKId (e.g. Burger, 1972) which is of earlyAlbian age, but the occasional presence ofdivision K2a suggests that the memberranges into the Middle Albian.

Surat SiltstoneThe Surat SiItstone, named after Surat

township, and defined by Reiser (1970), isconfined to the Surat Basin. The type sectionis continuous core in GSQ Surat No. 1 in theinterval from 50 to 460 feet (15-140 m);it consists of interbedded siltstone and mud­stone.

The formation crops out very poorlyindeed, and has only been identified in scat­tered outcrops in the western part of thebasin. North of Surat its position is markedby a broad band of Cainozoic alluvium alongthe Balonne River. In the east it probablycrops out in a few places, but has not beenidentified. It is present in the subsurfacethroughout the central part of the basin andalmost all our knowledge is based on welland water-bore data.

The sequence consists mainly of thinlyinterbedded siltstone and mudstone, withnumerous sandstone lenses at some levels. Inthe type section the basal fifth consistsmainly of mudstone, and the remainder pre­dominantly of siltstone. The mudstone isgenerally carbonaceous and commonly pyri­dc; the siltstone is grey to black, and con­tains carbonaceous plant remains and mica;the sandstone is fine to very fine-grained,lithic, and commonly contains glauconie andrare red grains presumed to be garnet. Exa­mination of cores from near Surat (Houston,1972) has shown that the sandstone andsiltstone contain 30 to 60 percent lithicgrains, 10 to 20 percent quartz, 10 to 20percent feldspar, and abundant glauconie,chlorite, and calcite. In the eastern part ofthe basin lithic sandstone is more important,and forms half the upper 50 m of thesequence in BMR Dalby No. 2; it is generallyvery fine to fine-grained, but medium­grained beds occur. Exon (I 972a) recordedabout 30 percent clay matrix and up to 50

percent carbonaceous debris in the sand­stone in the east, where high-angled cross­bedding is fairly common.

The Surat Siltstone rests conformably onthe thicker-bedded and somewhat coarser­grained Coreena Member. This boundary iswell defined on the electrical logs of petro­leum exploration wells, but is difficult toidentify on the gamma-ray logs of water­bores. The member's relation to theEromanga Basin sequence, with which itmay not be in lateral continuity, is not clear.A natural lithological correlate is the upperAlbian Allaru Mudstone, but palaeonto­logical evidence suggests that the Surat Silt­stone is older, and a correlate of the upperpart of the Coreena Member and the Toole­buc Limestone in the Eromanga Basin.

The formation is predominantly shallowmarine, although plant roots occur high inthe sequence in BMR Dalby No. 2 (Exon,1972a). The presence of abundant foramini­fera (Haig, 1973) and small shelly fossils(e.g. Gray, 1972, p. 45) at some levels indi­cates full marine, or almost full marine, con­ditions; the scarcity of dinoflagellates andother microplankton (Burger, 1972; & pers.comm.) suggests a shallow-water environ­ment. Glauconie is also assumed to indicatemarine conditions. Thus the organisms andthe fine-grained thinly bedded nature of thesediments suggest that the beds were laiddown in a shallow sea, mainly on tidal flatsand in protected bays. The carbonaceousmudstones may have been laid down incoastal swamps, and the cross-bedded sand­stones in stream and tidal channels. Com­pared with the Coreena Member there is ahigher proportion of marine beds.

The thickness of the member ranges fromgenerally 100 to 130 m.

The plant remains and small shelly fossilshave not yet been identified. Benthonic fora­minifera are abundant in GSQ Surat Nos. 1and 3 (Haig, 1973) with up to 16 calcar­eous and 9 arenaceous species in a singlesample (see Fig. 46); the foraminifera sug­gest correlation with the lower to middleAlbian Coreena Member in the EromangaBasin. Spores of Evans' (1966) divisionsKId and K2a, of Albian age, are present in

the Surat Basin (Burger, 1972), along withthe dinoflagellates Odontochiina operculataand Muderongia tetracantha and othermicroplankton. Ostracods have been re­ported (Terpstra, 1968, 1969) but not spe­cifically identified.

The fossil evidence clearly indicates thatthe member is of Albian age. The fora­minifera and pollens suggest that, by cor­relation with the Eromanga Basin, whereages based on shelly macrofossils (Day,1969) are fairly secure, the member is noyounger than middle Albian. Thus, althoughthe lithology suggests correlation with theupper Albian Allaru Mudstone, the palae­ontological data indicates that an early tomiddle Albian age is more likely.

Griman Creek FormationThe Cretaceous sequence cropping out in

the Surat Inlier* was named the GrimanCreek Group, after Griman Creek, by Jen­kins (1959); later he amended the name toGriman Creek Formation (Jenkins, 1960).Reiser (1970) fully defined the formation,and modified its usage slightly. Jenkins(1959) had separated the deeply weatheredpart of the Griman Creek Group as the Tel­gazli Formation, thinking it to be a differentunit; Thomas & Reiser (1968) have shownthat it is part of the Griman Creek Forma­tion, so the area mapped by Jenkins as Tel­gazli Formation is now included in the Gri­man Creek Formation. Because the sectionalong Griman Creek, which was nominatedby Jenkins (1959) as the type section, isonly the lower part of the sequence, Reiser(1970) redefined the type section as theinterval from 25 to 1135 feet (8-346 m) inthe continuously cored GSQ Surat No. 3hole, where it consists predominantly ofsandstone and siltstone.

The Griman Creek Formation is confinedto the Surat Basin, where it crops out exten­sively in the Surat Inlier and in a beltbetween the Moonie and Weir Rivers as fareast as Moonie. Farther west it crops outonly sporadically. Most of the outcrops arein mesas capped by a deep weathering pro­file up to 45 m thick, with fresh rock con-

121

fined to the lower slopes. In the central partof the basin it can be identified on the wire­line logs of petroleum exploration wells and,with less certainty, on the gamma-ray logs ofwater-bores.

The formation crops out poorly, exceptnear its base around Surat (Thomas &Reiser, 1968), where the sequence consistsof fine-grained labile sandstone grading intosiltstone and mudstone; macrofossils arefairly abundant, and in places form coquin­ites. Elsewhere the formation is covered byblack soil, through which calcareous bedsand concretions protrude, or forms part oftiie deeply weathered profile in which theoriginal bedding and grainsize are recogniz­able, although the rock has been extensivelyaltered. In fresh outcrops rounded glauconiepellets are common and mica is generallypresent; carbonaceous plant fragments alsooccur.

The best subsurface section is in GSQSurat No. 3, which has been illustrated anddescribed by Gray (1972). The most com­mon sequence consists of thinly interbeddedsiltstone, fine-grained sandstone, and mud­stone, but fine to medium-grained sandstoneis common in places. Some beds of intra­formational conglomerate and coal are pres­ent, particularly in the upper part of the for­mation.

Houston (1972) examined the cores fromGSQ Surat No. 3, and has shown that thelower 60 m is different in composition tothe upper 280 m. The rocks in the lowersequence contain about 50 percent lithicgrains, 10 percent quartz, 15 percent feld­spar,S percent chlorite and glauconie, and atotal of 20 to 30 percent clay matrix, car­bonate cement and pore space; the rocks inthe upper sequence are composed of about60 percent lithic grains, 5 percent quartz, 5percent feldspar, 15 percent chlorite andglauconie, and about the same proportion ofclay matrix, carbonate cement, and porespace. Gray (1972, p. 63) has suggestedthat the lower sequence is probably marine,and that the upper part is transitional (165­287 m) and freshwater (7-165 m).

* The area of Cretaceous outcrop bounded by Cainozoic sediments of the Condamine, Balonne, andMoonie Rivers.

the Surat Basin (Burger, 1972), along withthe dinoflagellates Odontochiina operculataand Muderongia tetracantha and othermicroplankton. Ostracods have been re­ported (Terpstra, 1968, 1969) but not spe­cifically identified.

The fossil evidence clearly indicates thatthe member is of Albian age. The fora­minifera and pollens suggest that, by cor­relation with the Eromanga Basin, whereages based on shelly macrofossils (Day,1969) are fairly secure, the member is noyounger than middle Albian. Thus, althoughthe lithology suggests correlation with theupper Albian Allaru Mudstone, the palae­ontological data indicates that an early tomiddle Albian age is more likely.

Griman Creek FormationThe Cretaceous sequence cropping out in

the Surat Inlier* was named the GrimanCreek Group, after Griman Creek, by Jen­kins (1959); later he amended the name toGriman Creek Formation (Jenkins, 1960).Reiser (1970) fully defined the formation,and modified its usage slightly. Jenkins(1959) had separated the deeply weatheredpart of the Griman Creek Group as the Tel­gazli Formation, thinking it to be a differentunit; Thomas & Reiser (1968) have shownthat it is part of the Griman Creek Forma­tion, so the area mapped by Jenkins as Tel­gazli Formation is now included in the Gri­man Creek Formation. Because the sectionalong Griman Creek, which was nominatedby Jenkins (1959) as the type section, isonly the lower part of the sequence, Reiser(1970) redefined the type section as theinterval from 25 to 1135 feet (8-346 m) inthe continuously cored GSQ Surat No. 3hole, where it consists predominantly ofsandstone and siltstone.

The Griman Creek Formation is confinedto the Surat Basin, where it crops out exten­sively in the Surat Inlier and in a beltbetween the Moonie and Weir Rivers as fareast as Moonie. Farther west it crops outonly sporadically. Most of the outcrops arein mesas capped by a deep weathering pro­file up to 45 m thick, with fresh rock con-

121

fined to the lower slopes. In the central partof the basin it can be identified on the wire­line logs of petroleum exploration wells and,with less certainty, on the gamma-ray logs ofwater-bores.

The formation crops out poorly, exceptnear its base around Surat (Thomas &Reiser, 1968), where the sequence consistsof fine-grained labile sandstone grading intosiltstone and mudstone; macrofossils arefairly abundant, and in places form coquin­ites. Elsewhere the formation is covered byblack soil, through which calcareous bedsand concretions protrude, or forms part oftiie deeply weathered profile in which theoriginal bedding and grainsize are recogniz­able, although the rock has been extensivelyaltered. In fresh outcrops rounded glauconiepellets are common and mica is generallypresent; carbonaceous plant fragments alsooccur.

The best subsurface section is in GSQSurat No. 3, which has been illustrated anddescribed by Gray (1972). The most com­mon sequence consists of thinly interbeddedsiltstone, fine-grained sandstone, and mud­stone, but fine to medium-grained sandstoneis common in places. Some beds of intra­formational conglomerate and coal are pres­ent, particularly in the upper part of the for­mation.

Houston (1972) examined the cores fromGSQ Surat No. 3, and has shown that thelower 60 m is different in composition tothe upper 280 m. The rocks in the lowersequence contain about 50 percent lithicgrains, 10 percent quartz, 15 percent feld­spar,S percent chlorite and glauconie, and atotal of 20 to 30 percent clay matrix, car­bonate cement and pore space; the rocks inthe upper sequence are composed of about60 percent lithic grains, 5 percent quartz, 5percent feldspar, 15 percent chlorite andglauconie, and about the same proportion ofclay matrix, carbonate cement, and porespace. Gray (1972, p. 63) has suggestedthat the lower sequence is probably marine,and that the upper part is transitional (165­287 m) and freshwater (7-165 m).

* The area of Cretaceous outcrop bounded by Cainozoic sediments of the Condamine, Balonne, andMoonie Rivers.

122

The rock types cropping out outside theSurat Inlier are similar to those describedabove (e.g. Exon, Mond et al., 1972).

The formation conformably overlies themuch finer-grained Surat Siltstone, fromwhich it can be distinguished in petroleumexploration wells by strong deflections onthe electric logs caused by porous and per­meable sandstones. Unfortunately, the boun­dary is very difficult to identify on thegamma-ray logs of water-bores. The forma­tion contains aquifers which give small sup­plies of chloride water. The upper surface isgenerally erosional, and in places it is over­lain by Cainozoic sediments.

In the Surat Inlier, and probably else­where, the Griman Creek Formation wasdeposited during the final regressive stage ofthe Cretaceous sea. The lower sequence,with its shelly coquinas composed mainly ofbrackish or freshwater forms, or both, wormburrows, and rare dinoflagellates, was pro­bably laid down in shallow-marine, beach.and lagoonal environments. The type ofsediment laid down also suggests these typesof environment.

The upper sequence contains freshwaterpelecypods, but no dinoflagellates, and isprobably largely non-marine. The presenceof coal and the abundance of intraforma­tional conglomerate also indicate that thebeds are non-marine. It is surprising thatglauconie pellets, and the related non­pelletal chlorite blebs are more common inthe upper sequence than in the lower. Glau­conie is almost ubiquitous in the sandstonesof the Rolling Downs Group and BungilFormation, many of which contain marinefossils. The abundance of glauconiein theapparently non-marine upper part of theGriman Creek Formation suggests that thesequence is marine, but it seems more likelythat the glauconie was derived from oldermarginal sequences rich in glauconie.

The maximum preserved thickness is400 m in the Surat Inlier, but it is thinnertowards the margins of the basin.

Fossil collections made by Laing & Alien(1955) included· Peratobelus sp. (Romafauna) and Dimitobelus sp. (Tambo fauna).Jenkins (1960) recorded Peratobelus aus-

tralis , nine species of pelecypod, and onegastropod. Collections made by Thomas &Reiser (1968) were examined by R. W.Day, who has reported that most of themwere undescribed forms. Only the belem­nites (Day found only a single belemnitespecimen: Peratobelus sp.) are definitelymarine, and shells higher in the sequence inthe Surat and Dalby Sheet areas are almostcertainly freshwater forms, reminiscent ofthe faunas of the Winton Formation. Thepresence of Dimitobelus sp. indicates thatthe lower part of the formation is not olderthan Albian (e.g. Day, 1969). Foraminiferawere not found by Haig (1973).

The plant macrofossils have not beenidentified, but spores of Evans' (1966) divi­sion K2a (e.g. Burger, 1976) of middleAlbian age are present.

On stratigraphic and palaeontological evi­dence the formation is probably of middleAlbian age, but it possibly ranges into thelate Albian.

CAINOZOIC ROCKS(Table 21)

GabbroThe Tabor Gabbro in the northwest is

probably of Tertiary age and is believed tobe genetically related to the Oligocene andMiocene basalts in the north and east(Mollan et al., 1972). It consists of a basin­shaped sill and three stocks of olivine micro­teschenite that intrude the Hutton Sand­stone. The sill is elliptical, with a long axisof 8 km, and is about 45 m thick.

Two small bosses of gabbro have beenrecorded in the northeast (Mollan et al.,1972, p. 76); they are probably of Mesozoicage, but could be Tertiary.

The gabbroic rocks recorded south ofRoma in the AAO Brucedale No. 1 andnearby wells appear to transgress the sur­rounding Lower Jurassic sediments slightlyand are probably part of a large sill. Theyare assumed to correlate with the Oligocene­Miocene basalts cropping out to the north.

In the Coonamble Lobe of the SuratBasin, south of the area studied, gabbro sillsare present in anumber of wells (e.g. Amo­seas Bohena No. 1); they may also be ofmid-Tertiary age.

122

The rock types cropping out outside theSurat Inlier are similar to those describedabove (e.g. Exon, Mond et al., 1972).

The formation conformably overlies themuch finer-grained Surat Siltstone, fromwhich it can be distinguished in petroleumexploration wells by strong deflections onthe electric logs caused by porous and per­meable sandstones. Unfortunately, the boun­dary is very difficult to identify on thegamma-ray logs of water-bores. The forma­tion contains aquifers which give small sup­plies of chloride water. The upper surface isgenerally erosional, and in places it is over­lain by Cainozoic sediments.

In the Surat Inlier, and probably else­where, the Griman Creek Formation wasdeposited during the final regressive stage ofthe Cretaceous sea. The lower sequence,with its shelly coquinas composed mainly ofbrackish or freshwater forms, or both, wormburrows, and rare dinoflagellates, was pro­bably laid down in shallow-marine, beach.and lagoonal environments. The type ofsediment laid down also suggests these typesof environment.

The upper sequence contains freshwaterpelecypods, but no dinoflagellates, and isprobably largely non-marine. The presenceof coal and the abundance of intraforma­tional conglomerate also indicate that thebeds are non-marine. It is surprising thatglauconie pellets, and the related non­pelletal chlorite blebs are more common inthe upper sequence than in the lower. Glau­conie is almost ubiquitous in the sandstonesof the Rolling Downs Group and BungilFormation, many of which contain marinefossils. The abundance of glauconiein theapparently non-marine upper part of theGriman Creek Formation suggests that thesequence is marine, but it seems more likelythat the glauconie was derived from oldermarginal sequences rich in glauconie.

The maximum preserved thickness is400 m in the Surat Inlier, but it is thinnertowards the margins of the basin.

Fossil collections made by Laing & Alien(1955) included· Peratobelus sp. (Romafauna) and Dimitobelus sp. (Tambo fauna).Jenkins (1960) recorded Peratobelus aus-

tralis , nine species of pelecypod, and onegastropod. Collections made by Thomas &Reiser (1968) were examined by R. W.Day, who has reported that most of themwere undescribed forms. Only the belem­nites (Day found only a single belemnitespecimen: Peratobelus sp.) are definitelymarine, and shells higher in the sequence inthe Surat and Dalby Sheet areas are almostcertainly freshwater forms, reminiscent ofthe faunas of the Winton Formation. Thepresence of Dimitobelus sp. indicates thatthe lower part of the formation is not olderthan Albian (e.g. Day, 1969). Foraminiferawere not found by Haig (1973).

The plant macrofossils have not beenidentified, but spores of Evans' (1966) divi­sion K2a (e.g. Burger, 1976) of middleAlbian age are present.

On stratigraphic and palaeontological evi­dence the formation is probably of middleAlbian age, but it possibly ranges into thelate Albian.

CAINOZOIC ROCKS(Table 21)

GabbroThe Tabor Gabbro in the northwest is

probably of Tertiary age and is believed tobe genetically related to the Oligocene andMiocene basalts in the north and east(Mollan et al., 1972). It consists of a basin­shaped sill and three stocks of olivine micro­teschenite that intrude the Hutton Sand­stone. The sill is elliptical, with a long axisof 8 km, and is about 45 m thick.

Two small bosses of gabbro have beenrecorded in the northeast (Mollan et al.,1972, p. 76); they are probably of Mesozoicage, but could be Tertiary.

The gabbroic rocks recorded south ofRoma in the AAO Brucedale No. 1 andnearby wells appear to transgress the sur­rounding Lower Jurassic sediments slightlyand are probably part of a large sill. Theyare assumed to correlate with the Oligocene­Miocene basalts cropping out to the north.

In the Coonamble Lobe of the SuratBasin, south of the area studied, gabbro sillsare present in anumber of wells (e.g. Amo­seas Bohena No. 1); they may also be ofmid-Tertiary age.

-----------------------------------

TABLE 21. CAINOZOIC IGNEOUS ROCKS AND SEDlMENTS

Name(map symbol)

LithologyMaximumthickness

(m)Fossils and Environmel1/

of DepositionRelalions Main

References

Upper Oligocene Springsure Flood basalts, largely olivine 300+ Subaerial extrusion of lava on(23-27 m.y.) basalts basalt. Minor trachyte and uneven surface

(Tob) pyroclastics

Tertiary (Tb) Olivine basalt and pyroclas- Subaerial extrusion(probably ticsOligocene-Miocene)Tertiary (Tt) Gabbro intrusions: sills, 50 Intrusions(probably stocks, and plugs for sillsOligocene-Miocene)

Tertiary (T) Alluvium: weakly to well 30+ Deposition by streams ances-(largely older consolidated sandstone, con- tral to present onesTertiary) glomerate, siltstone; silicified

near Millmerran

Olivine basalt, some tuff andagglomerate

consolidated sand­conglomerate, silt­mudstone; residual

Pleistocene andHolocene

Mainly Pleistocene

Cainowic

Pliocene

Oligocene-Miocene(18-24 m.y.)

(Qa)

(Q)

(Czc)

(Czs)

ChinchillaSand

(Tc)

(Tmb)

Alluvium: unconsolidatedgravel, sand, silt, clay, soil

Alluvium as above on olderriver terraces and in valleys.Also general sand, gravel,and soil coverCollapsed sheets of TertiarybasaltWeaklystone,stone,soilWeakly consolidated labilesand, grading into grit andconglomerate, and also tosandy clay. Minor thin lithi­fied calcareous beds

100+

100+

100

5

30

120

Abundant vertebrate fossils inSE include Diprotodon andother mammals, birds, reptiles,and fish. Present-day streamsPleistocene streams, also col­luvial and aeolian

Subaerial collapse due to ero­sion of soft underlying unitsColluvium, alluvium

Abundant vertebrate fossils:Euryzygoma dunense and othermammals, crocodiles, tortoises,goannas, fishes, and birds. De­position by ancestral Conda­mine R.Subaerial extrusion of basalton uneven surface

Overlies or grades laterallyinto Qs. Unconformably over­lies older units

Disconformably overlies olderCainowic units. Unconform­ably overlies pre-CainozoicunitsUnconformably overlies severalU. Permian and Triassic unitsUnconformably overlies Juras­sic sediments

Unconformably overlies Juras­sic sediments

Include Main Range Volcanics,Amby basalts, and basalts ofNSW central volcanic pro­vince. Unconformable onMesozoic unitsUnconformable on Mesozoicand Permian sediments

Unconformable on older units

Intruded into Jurassic rocks inoutcrop (e.g. Tabor gabbro)and in subsurface. Intrusiveequivalents of Tmb, Tob, andTbLargely older than basalt. Un­conformable on Mesozoic andPalaeozoic rocks

Bartholomai(1972; Appendix3); Senior (1970)

Senior (1970)

Mollan et al.(1969)

Woods (1960),Bartholomai &Woods (Appen­dix 2)

Webb et al.(1967) ,McDougall &Wilkinson (1967)

Mollan et al.(1969, pp. 53-4),Webb &McDougall(1967)Hill & Denmead(1960, pp. 366-9)

Mollan et al.(1972, pp. 76-8)

-----------------------------------

TABLE 21. CAINOZOIC IGNEOUS ROCKS AND SEDlMENTS

Name(map symbol)

LithologyMaximumthickness

(m)Fossils and Environmel1/

of DepositionRelalions Main

References

Upper Oligocene Springsure Flood basalts, largely olivine 300+ Subaerial extrusion of lava on(23-27 m.y.) basalts basalt. Minor trachyte and uneven surface

(Tob) pyroclastics

Tertiary (Tb) Olivine basalt and pyroclas- Subaerial extrusion(probably ticsOligocene-Miocene)Tertiary (Tt) Gabbro intrusions: sills, 50 Intrusions(probably stocks, and plugs for sillsOligocene-Miocene)

Tertiary (T) Alluvium: weakly to well 30+ Deposition by streams ances-(largely older consolidated sandstone, con- tral to present onesTertiary) glomerate, siltstone; silicified

near Millmerran

Olivine basalt, some tuff andagglomerate

consolidated sand­conglomerate, silt­mudstone; residual

Pleistocene andHolocene

Mainly Pleistocene

Cainowic

Pliocene

Oligocene-Miocene(18-24 m.y.)

(Qa)

(Q)

(Czc)

(Czs)

ChinchillaSand

(Tc)

(Tmb)

Alluvium: unconsolidatedgravel, sand, silt, clay, soil

Alluvium as above on olderriver terraces and in valleys.Also general sand, gravel,and soil coverCollapsed sheets of TertiarybasaltWeaklystone,stone,soilWeakly consolidated labilesand, grading into grit andconglomerate, and also tosandy clay. Minor thin lithi­fied calcareous beds

100+

100+

100

5

30

120

Abundant vertebrate fossils inSE include Diprotodon andother mammals, birds, reptiles,and fish. Present-day streamsPleistocene streams, also col­luvial and aeolian

Subaerial collapse due to ero­sion of soft underlying unitsColluvium, alluvium

Abundant vertebrate fossils:Euryzygoma dunense and othermammals, crocodiles, tortoises,goannas, fishes, and birds. De­position by ancestral Conda­mine R.Subaerial extrusion of basalton uneven surface

Overlies or grades laterallyinto Qs. Unconformably over­lies older units

Disconformably overlies olderCainowic units. Unconform­ably overlies pre-CainozoicunitsUnconformably overlies severalU. Permian and Triassic unitsUnconformably overlies Juras­sic sediments

Unconformably overlies Juras­sic sediments

Include Main Range Volcanics,Amby basalts, and basalts ofNSW central volcanic pro­vince. Unconformable onMesozoic unitsUnconformable on Mesozoicand Permian sediments

Unconformable on older units

Intruded into Jurassic rocks inoutcrop (e.g. Tabor gabbro)and in subsurface. Intrusiveequivalents of Tmb, Tob, andTbLargely older than basalt. Un­conformable on Mesozoic andPalaeozoic rocks

Bartholomai(1972; Appendix3); Senior (1970)

Senior (1970)

Mollan et al.(1969)

Woods (1960),Bartholomai &Woods (Appen­dix 2)

Webb et al.(1967) ,McDougall &Wilkinson (1967)

Mollan et al.(1969, pp. 53-4),Webb &McDougall(1967)Hill & Denmead(1960, pp. 366-9)

Mollan et al.(1972, pp. 76-8)

124

BasaltRemnants of formerly extensive subhori­

zontal basalt flows are present in the north­ern part of the Surat Basin, and along theeastern margin. All are of Oligocene or Mio­cene age. Extrusion took place over a periodof about 10 million years, and the volcanismwas apparently related to a single longperiod of epeirogenic uplift. There is ageneral decrease in age of the basalts fromthe northwest to southeast.

Most of the northern basalts appear tohave been extruded along the fault zonesassociated with the Merivale Syncline andthe Springsure-Serocold Anticline.

The basalt... associated with the Spring­sure-Serocold Anticline have been describedby Mollan et al. (1969) and Mollan et al.(1972). Olivine basalt predominates, butfine-grained olivine-free basalt is common,and a few intermediate flows are present.Pyroclastic rocks are common around andnorth of Springsure. The volcanic sequenceis up to 250 m thick, and whole rock K-Ardating has shown that the lavas are of Oligo­cene age (Webb & McDougall, 1967).

The basalts in the Merivale Syncline(Exon et al., 1970) are thinner and lesswidespread. Several flows are present witha total maximum preserved thickness of80 m. They appear to have flowed down thesynclinal depression from the north. Thebasalts range from massive to slightly vesi­cular, and both tholeiitic olivine basalt andolivine basalt are represented. Despite exten­sive erosion, which has involved inversion ofrelief, the basalt bodies still extend for 100km down the synclinal axis. K-Ar dating ofwhole rock samples has shown that they areof late Oligocene to early Miocene age(Exon et al., 1970). The basalts north ofRoma are similar and of comparable age(Langford-Smith, Dury, & McDougall,1966), but were extruded from local vents.

The basalts north of Taroom in theMimosa Syncline (Mollan et al., 1972) arevesicular, amygdaloidal, and massive, andare interbedded with subordinate sandstone.They are up to 45 m thick.

The westerly outrunners of the MainRange Volcanics (Stevens, 1965; Webb,

Stevens, & McDougall, 1967) crop outalong the eastern margin of the basin (Exonet al., 1968; Exon, Mond et al., 1972). Theyconsist essentially of alkaline olivine basaltand most of them appear to have been erup­ted from fissures along the line of the pre­sent-day Main Range, and to have made theirway down-slope into this area, althoughlocal vents also play a part (Exon et al.,1968). Most of them have been extensivelyeroded and some have been covered by allu­vium. The sequence consists mainly of mas­sive and vesicular basalts with subordinateagglomerate and tuff, and minor whiteclayey tuff? and green clay. Most of thebasalts are very fine-grained, but some con­tain acicular feldspar, and a few are rich inolivine phenocrysts up to 3 cm across.Columnar basalt is locally common (Fig.47).

The maximum thickness cropping outprobably exceeds 120 m, and flows of basaltover 30 m thick have been recorded in water­bores below the alluvium along the Conda­mine River near Dalby. K-Ar dating (Webbet al., 1967) has shown that the MainRange Volcanics are of late Oligocene toearly Miocene age.

Outliers of fine-grained basalt of the Cen­tral Volcanics Province of New South Walesare present in the southeast. They crop outin small and low rises, but considerablymore basalt may be present under the Qua­ternary sediments. The volcanic provinceextends as far south as Armidale, and K-Ardating has yielded lowermost Miocene ages(McDougall & Wilkinson, 1967).

Cainozoic SedimentsIn Late Cretaceous time the southerly tilt

of the basin increased and the Cretaceousrocks were partly eroded. No Upper Creta­ceous sediments are preserved. By EarlyTertiary time the land surface had stabilized,and periodic variations in rainfall resulted ina strongly fluctuating water-table that gaverise to a deeply weathered profile on thebevelled Cretaceous rocks. Renewed tec­tonic movement, which was probably relatedto the Oligocene-Miocene volcanism andepeirogenic movements in the north andeast, led to subsidence of the central part of

124

BasaltRemnants of formerly extensive subhori­

zontal basalt flows are present in the north­ern part of the Surat Basin, and along theeastern margin. All are of Oligocene or Mio­cene age. Extrusion took place over a periodof about 10 million years, and the volcanismwas apparently related to a single longperiod of epeirogenic uplift. There is ageneral decrease in age of the basalts fromthe northwest to southeast.

Most of the northern basalts appear tohave been extruded along the fault zonesassociated with the Merivale Syncline andthe Springsure-Serocold Anticline.

The basalt... associated with the Spring­sure-Serocold Anticline have been describedby Mollan et al. (1969) and Mollan et al.(1972). Olivine basalt predominates, butfine-grained olivine-free basalt is common,and a few intermediate flows are present.Pyroclastic rocks are common around andnorth of Springsure. The volcanic sequenceis up to 250 m thick, and whole rock K-Ardating has shown that the lavas are of Oligo­cene age (Webb & McDougall, 1967).

The basalts in the Merivale Syncline(Exon et al., 1970) are thinner and lesswidespread. Several flows are present witha total maximum preserved thickness of80 m. They appear to have flowed down thesynclinal depression from the north. Thebasalts range from massive to slightly vesi­cular, and both tholeiitic olivine basalt andolivine basalt are represented. Despite exten­sive erosion, which has involved inversion ofrelief, the basalt bodies still extend for 100km down the synclinal axis. K-Ar dating ofwhole rock samples has shown that they areof late Oligocene to early Miocene age(Exon et al., 1970). The basalts north ofRoma are similar and of comparable age(Langford-Smith, Dury, & McDougall,1966), but were extruded from local vents.

The basalts north of Taroom in theMimosa Syncline (Mollan et al., 1972) arevesicular, amygdaloidal, and massive, andare interbedded with subordinate sandstone.They are up to 45 m thick.

The westerly outrunners of the MainRange Volcanics (Stevens, 1965; Webb,

Stevens, & McDougall, 1967) crop outalong the eastern margin of the basin (Exonet al., 1968; Exon, Mond et al., 1972). Theyconsist essentially of alkaline olivine basaltand most of them appear to have been erup­ted from fissures along the line of the pre­sent-day Main Range, and to have made theirway down-slope into this area, althoughlocal vents also play a part (Exon et al.,1968). Most of them have been extensivelyeroded and some have been covered by allu­vium. The sequence consists mainly of mas­sive and vesicular basalts with subordinateagglomerate and tuff, and minor whiteclayey tuff? and green clay. Most of thebasalts are very fine-grained, but some con­tain acicular feldspar, and a few are rich inolivine phenocrysts up to 3 cm across.Columnar basalt is locally common (Fig.47).

The maximum thickness cropping outprobably exceeds 120 m, and flows of basaltover 30 m thick have been recorded in water­bores below the alluvium along the Conda­mine River near Dalby. K-Ar dating (Webbet al., 1967) has shown that the MainRange Volcanics are of late Oligocene toearly Miocene age.

Outliers of fine-grained basalt of the Cen­tral Volcanics Province of New South Walesare present in the southeast. They crop outin small and low rises, but considerablymore basalt may be present under the Qua­ternary sediments. The volcanic provinceextends as far south as Armidale, and K-Ardating has yielded lowermost Miocene ages(McDougall & Wilkinson, 1967).

Cainozoic SedimentsIn Late Cretaceous time the southerly tilt

of the basin increased and the Cretaceousrocks were partly eroded. No Upper Creta­ceous sediments are preserved. By EarlyTertiary time the land surface had stabilized,and periodic variations in rainfall resulted ina strongly fluctuating water-table that gaverise to a deeply weathered profile on thebevelled Cretaceous rocks. Renewed tec­tonic movement, which was probably relatedto the Oligocene-Miocene volcanism andepeirogenic movements in the north andeast, led to subsidence of the central part of

125

Fig. 47. Columnar basalt of Tertiary age in Malaoff Quarry, 6 km east of Jimbour.

the basin and to extensive stream sedimenta­tion.

The thickest deposits (Fig. 48) were laiddown by the Condamine-Balonne andMacintyre-Weir River systems. About one­quarter of the present Surat Basin inQueensland is covered by Cainozoic sedi­ments over 20 m thick. In outcrop (see geo­logical map) they can be broadly subdividedinto: the Tertiary Chinchil1a Sand (Tc),general Tertiary sediments (T), alluvium ofold flood plains (Q), and al1uvium ofpresent-day flood plains (Qa). In the sub­surface these subdivisions are only locallyrecognizable, and all Cainozoic sedimentshave been grouped together (as Cz) inFigure 48.

The five major depositional systems are:the Condamine system southeast of Chin­chilla, the Condamine system between Caba­win and Surat, the Balonne system, the

Macintyre-Weir system, and the Mooniesystem east of the Alton Oil Field. All arepart of the drainage network flowing south­west into the Darling River. West of theKumbarilla Ridge: the alluvia of the Balonneand Macintyre systems rest on downfoldeddeeply weathered Cretaceous rocks (Senior,1970); this suggests that the Cainozoicbasins have been formed by sagging of theolder rocks. Abundant vertebrate faunashave been recovered east of the KumbarillaRidge, but none to the west; this may meanthat lush vegetation was confined to the east,with intermittent streams and drier countryin the west.

The Condamine System southeast ofChinchilla consists of Pliocene stream depo­sits of the Chinchilla Sand and its equiva­lents, Pleistocene stream and lake deposits,and Quaternary stream deposits (Lumsden,1966). Up to 100 m of sediment was laid

125

Fig. 47. Columnar basalt of Tertiary age in Malaoff Quarry, 6 km east of Jimbour.

the basin and to extensive stream sedimenta­tion.

The thickest deposits (Fig. 48) were laiddown by the Condamine-Balonne andMacintyre-Weir River systems. About one­quarter of the present Surat Basin inQueensland is covered by Cainozoic sedi­ments over 20 m thick. In outcrop (see geo­logical map) they can be broadly subdividedinto: the Tertiary Chinchil1a Sand (Tc),general Tertiary sediments (T), alluvium ofold flood plains (Q), and al1uvium ofpresent-day flood plains (Qa). In the sub­surface these subdivisions are only locallyrecognizable, and all Cainozoic sedimentshave been grouped together (as Cz) inFigure 48.

The five major depositional systems are:the Condamine system southeast of Chin­chilla, the Condamine system between Caba­win and Surat, the Balonne system, the

Macintyre-Weir system, and the Mooniesystem east of the Alton Oil Field. All arepart of the drainage network flowing south­west into the Darling River. West of theKumbarilla Ridge: the alluvia of the Balonneand Macintyre systems rest on downfoldeddeeply weathered Cretaceous rocks (Senior,1970); this suggests that the Cainozoicbasins have been formed by sagging of theolder rocks. Abundant vertebrate faunashave been recovered east of the KumbarillaRidge, but none to the west; this may meanthat lush vegetation was confined to the east,with intermittent streams and drier countryin the west.

The Condamine System southeast ofChinchilla consists of Pliocene stream depo­sits of the Chinchilla Sand and its equiva­lents, Pleistocene stream and lake deposits,and Quaternary stream deposits (Lumsden,1966). Up to 100 m of sediment was laid

126

D Cainozoic sedimentsthicker than 20 m

50I

100 km

Data points

1:·::-:::] Cainozoic sediments....... thinner than 20 m

F7/7J Deeply weatheredtLLL:J Mesozoic sediments

~ Fresh Mesozoic~ sediments

--:10-- Thickness of Cainozoicsequence (m)

(Balonne system contoursmodified after SMior, 1970)

Fig. 48. Distribution and thickness of Cainozoic sequence.

126

D Cainozoic sedimentsthicker than 20 m

50I

100 km

Data points

1:·::-:::] Cainozoic sediments....... thinner than 20 m

F7/7J Deeply weatheredtLLL:J Mesozoic sediments

~ Fresh Mesozoic~ sediments

--:10-- Thickness of Cainozoicsequence (m)

(Balonne system contoursmodified after SMior, 1970)

Fig. 48. Distribution and thickness of Cainozoic sequence.

down in a depression cut in the relativelyunresistant Walloon Coal Measures byvarious streams. The sequence forms abroad plain that falls to the northwest fromabout 380 m south of Millmerran to about300 m near Chinchilla.

The Chinchilla Sand (Woods, 1956; Bar­tholomai & Woods, Appendix 2), whichmay be 95 m thick near Dalby (Lumsden,1966), consists of variably consolidatedsandstone, grit, conglomerate, silt, and clay.The Kumbarilla Ridge possibly preventedoutlet to the west, and the general flow dur­ing deposition of this 'fan-type' alluvium(Lumsden, 1966) may have been to theeast, or to the northeast via the Durongplain and the Boyne River (G. G. Beck­mann, pers. comm.). In Pleistocene timethe area acted as an internal drainage basin,at least periodically, and lake and streammuds, silts, and sands were laid down(Lumsden, 1966); these are still generallyunconsolidated, although somewhat calcar­eous, and have a maximum thickness of upto 100 m in the southeast. The vertebratefauna (Bartholomai, 1972; Appendix 3) isdominated by marsupials. Bartholomai(1973) on fauna! evidence states that duringboth Pliocene and Pleistocene times theregion 'comprised well watered open sclero­phyll and open grassland areas ideally suitedto grazing and browsing macropodids.' Inlate Pleistocene and Holocene times theelevation of the alluvium has certainlyexceeded that of the Kumbarilla Ridge, andstream sands and silts (probably less than20 m thick) have been laid down by thenorthwesterly-flowing Condamine River andits tributaries.

The Condamine System between Cabawinand Surat consists essentially of the depositsof the westerly-flowing Condamine Riverand of a tributary lobe north of Cabawin(Fig. 48). Up to 50 m of mud, silt, sand,and gravel was deposited by westerly-flow­ing streams in a valley cut in and throughthe deep-weathering profile. Along the Con­damine River itself the restriction of theQuaternary alluvium to the present-dayflood plain, which lies to the south of exten­sive alluvial Tertiary deposits, suggests that

127

the river migrated laterally to the south intothe basin.

The Balonne System (see Senior, 1970)consists of up to 220 m (Fig. 48) of asequence of strongly cross-bedded uncon­solidated quartz-rich sands, gravel, silt and'ironstone', which was laid down by fast­flowing, though probably intermittent,streams. Because the Cainozoic sedimentsrest on deeply weathered Cretaceous sedi­ments, which he believes to have been down­warped after they had been weathered on anearly flat land surface, Senior (1970) con­siders that active tectonism occurred in theCainozoic. However, the thickening ofvarious Jurassic units into the depression(Figs 19-23) suggests that it is an ancientstructure in which tectonic movements andcompaction have played a part for over 170million years, and the downwarping of thedeeply weathered profile could be duemainly to compaction of the underlying sedi­ments.

The Macintyre-Weir System is generallysimilar to the Balonne System (Senior,1970) although the isopachs and structuralmaps show that it does not rest on a pre­Tertiary depression. The sediments consistof unconsolidated stream sands, clayeysands, and gravels, and are up to 95 m thick(Fig. 48). In Tertiary time, when gradientswere steeper, the ancestral streams probablycut a broad deep valley into the down­warped deeply weathered profile; the valleywas filled in as the gradient decreased.

The Moonie System contains up to 50 mof unconsolidated sandy sediment depositedby westerly-flowing streams (Fig. 48) thatcut into and through the deep-weatheringprofile. Consolidated Tertiary outcrops flankthe present stream along part of its course.

WEATHERING PHENOMENA

Weathering is widespread in the SuratBasin, where there has been remarkablylittle sedimentation since mid-Cretaceoustime. The Tertiary land surface was deeplyweathered and toughened, and the erodedremnants of this surface dominate the topo­graphy in the southern part of the basinwhere they obscure the older structural

down in a depression cut in the relativelyunresistant Walloon Coal Measures byvarious streams. The sequence forms abroad plain that falls to the northwest fromabout 380 m south of Millmerran to about300 m near Chinchilla.

The Chinchilla Sand (Woods, 1956; Bar­tholomai & Woods, Appendix 2), whichmay be 95 m thick near Dalby (Lumsden,1966), consists of variably consolidatedsandstone, grit, conglomerate, silt, and clay.The Kumbarilla Ridge possibly preventedoutlet to the west, and the general flow dur­ing deposition of this 'fan-type' alluvium(Lumsden, 1966) may have been to theeast, or to the northeast via the Durongplain and the Boyne River (G. G. Beck­mann, pers. comm.). In Pleistocene timethe area acted as an internal drainage basin,at least periodically, and lake and streammuds, silts, and sands were laid down(Lumsden, 1966); these are still generallyunconsolidated, although somewhat calcar­eous, and have a maximum thickness of upto 100 m in the southeast. The vertebratefauna (Bartholomai, 1972; Appendix 3) isdominated by marsupials. Bartholomai(1973) on fauna! evidence states that duringboth Pliocene and Pleistocene times theregion 'comprised well watered open sclero­phyll and open grassland areas ideally suitedto grazing and browsing macropodids.' Inlate Pleistocene and Holocene times theelevation of the alluvium has certainlyexceeded that of the Kumbarilla Ridge, andstream sands and silts (probably less than20 m thick) have been laid down by thenorthwesterly-flowing Condamine River andits tributaries.

The Condamine System between Cabawinand Surat consists essentially of the depositsof the westerly-flowing Condamine Riverand of a tributary lobe north of Cabawin(Fig. 48). Up to 50 m of mud, silt, sand,and gravel was deposited by westerly-flow­ing streams in a valley cut in and throughthe deep-weathering profile. Along the Con­damine River itself the restriction of theQuaternary alluvium to the present-dayflood plain, which lies to the south of exten­sive alluvial Tertiary deposits, suggests that

127

the river migrated laterally to the south intothe basin.

The Balonne System (see Senior, 1970)consists of up to 220 m (Fig. 48) of asequence of strongly cross-bedded uncon­solidated quartz-rich sands, gravel, silt and'ironstone', which was laid down by fast­flowing, though probably intermittent,streams. Because the Cainozoic sedimentsrest on deeply weathered Cretaceous sedi­ments, which he believes to have been down­warped after they had been weathered on anearly flat land surface, Senior (1970) con­siders that active tectonism occurred in theCainozoic. However, the thickening ofvarious Jurassic units into the depression(Figs 19-23) suggests that it is an ancientstructure in which tectonic movements andcompaction have played a part for over 170million years, and the downwarping of thedeeply weathered profile could be duemainly to compaction of the underlying sedi­ments.

The Macintyre-Weir System is generallysimilar to the Balonne System (Senior,1970) although the isopachs and structuralmaps show that it does not rest on a pre­Tertiary depression. The sediments consistof unconsolidated stream sands, clayeysands, and gravels, and are up to 95 m thick(Fig. 48). In Tertiary time, when gradientswere steeper, the ancestral streams probablycut a broad deep valley into the down­warped deeply weathered profile; the valleywas filled in as the gradient decreased.

The Moonie System contains up to 50 mof unconsolidated sandy sediment depositedby westerly-flowing streams (Fig. 48) thatcut into and through the deep-weatheringprofile. Consolidated Tertiary outcrops flankthe present stream along part of its course.

WEATHERING PHENOMENA

Weathering is widespread in the SuratBasin, where there has been remarkablylittle sedimentation since mid-Cretaceoustime. The Tertiary land surface was deeplyweathered and toughened, and the erodedremnants of this surface dominate the topo­graphy in the southern part of the basinwhere they obscure the older structural

128

Fig. 49. Leached, mottled and weakly silicified mudstone, with blocky weathering, in deep-weatheringprofile developed on the Coreena Member. Cut beside Warrego Highway, 18 km west of Miles. The

outcrop is 2 m high.

trends. Much of the area is blanketed byrecent soils.

Tertiary Deep WeatheringWoolnough (1927) coined the term 'duri­

crust' for the indurated capping on aweathering profile, and stated that the duri­crust was apparently of the same agethroughout Australia. He thought that theduricrust formed 'during a period of highlyperfect peneplanation, about Miocene inage, on a land surface almost devoid oftopographic relief, and in a climate markedby the dominantly seasonal character of therainfall.' He pointed out that the length ofthe 'seasons' was unimportant, and that theremay have been annual wet seasons or occa­sional wet periods alternating with years ofdrought.

In the Surat Basin the weathered profilesoccur as erosional remnants, and wereformed essentially as Woolnough suggested,but in pre-Miocene time. Such profiles arecommon, but Exon et al. (1970) havepointed out that 'the crust of the profile isseldom preserved and hence the term "deep­weathering profile" is preferred to "duricrustprofile" '.

Typical profiles have been described byExon et al. (1970) and Thomas & Reiser( 1968); they consist of 10 to 40 m ofweathered Cretaceous lithic sandstone, silt­stone, and mudstone. Both mottled andpallid zones exist, but cannot always bedifferentiated. In most places the upper partof the profile is tougher than the fresh rock.The morphology of the outcrops is quitevariable; homogeneous fine-grained rocks

128

Fig. 49. Leached, mottled and weakly silicified mudstone, with blocky weathering, in deep-weatheringprofile developed on the Coreena Member. Cut beside Warrego Highway, 18 km west of Miles. The

outcrop is 2 m high.

trends. Much of the area is blanketed byrecent soils.

Tertiary Deep WeatheringWoolnough (1927) coined the term 'duri­

crust' for the indurated capping on aweathering profile, and stated that the duri­crust was apparently of the same agethroughout Australia. He thought that theduricrust formed 'during a period of highlyperfect peneplanation, about Miocene inage, on a land surface almost devoid oftopographic relief, and in a climate markedby the dominantly seasonal character of therainfall.' He pointed out that the length ofthe 'seasons' was unimportant, and that theremay have been annual wet seasons or occa­sional wet periods alternating with years ofdrought.

In the Surat Basin the weathered profilesoccur as erosional remnants, and wereformed essentially as Woolnough suggested,but in pre-Miocene time. Such profiles arecommon, but Exon et al. (1970) havepointed out that 'the crust of the profile isseldom preserved and hence the term "deep­weathering profile" is preferred to "duricrustprofile" '.

Typical profiles have been described byExon et al. (1970) and Thomas & Reiser( 1968); they consist of 10 to 40 m ofweathered Cretaceous lithic sandstone, silt­stone, and mudstone. Both mottled andpallid zones exist, but cannot always bedifferentiated. In most places the upper partof the profile is tougher than the fresh rock.The morphology of the outcrops is quitevariable; homogeneous fine-grained rocks

tend to weather into blocks (Fig. 49), but inbedded rocks the bedding is accentuated.

The original grainsize, distribution of rocktypes, and bedding characteristics are identi­fiable despite the deep weathering. Withinthe profile calcite has been leached and feld­spar has broken down to kaolin that formsan interstitial matrix. Iron oxides have beenformed by the alteration of grains of otheriron and ferromagnesian minerals. Resistantlithic and quartz grains are relativelyunaffected.

During the long stable period that fol­lowed Cretaceous deposition in the GreatArtesian Basin (i.e. from Late Cretaceousonward) erosion led eventually to pedi­planation. The pediplaned surface was sub­jected to a long period of weathering underconditions characterized by variable rain­fall. Constant fluctuations of the water-tableresulted in leaching in the zone of fluctua­tion, and in the development of a weatheringprofile that was very deep and probably hada resistant ferruginous capping.

In Oligocene time epeirogenic movementsbegan. They resulted in an increase in thebasinward tilt and led to some erosion of thepediplaned surface before the Oligocene­Miocene basalts were poured out over largeareas (Exon et al., 1970); more erosion fol­lowed.

Headward erosion by northerly-flowingstreams has stripped most of the deep­weathering profile and basalts from thestrongly uplifted northern part of the areawhere the land surface has been lowered inplaces by 600 m since the Miocene.

In the south, where uplift was much less,headward erosion by southwesterly-flowingstreams has been relatively less effective. Asa result large areas of deeply weatheredmaterial form plateaux along the majordivides, and mesas and buttes elsewhere.More than half the area of Cretaceous rocksexposed in the Surat Basin is deeplyweathered. The relief attributable to theresistant deeply weathered surface is con­siderable, and in the Surat Inlier the surfacelies 100 m above the surrounding streams,which are virtually at base level.

129

Thomas & Rieser (1968, p. 45) have dis­cussed the occurrence of opal in the SuratInlier, where it occurs in the deep-weather­ing profile of the Griman Creek Formation,particularly near its base. Silica-rich solu­tions, the silica coming from higher in theprofile, apparently percolated downwarduntil they came to a permeability barrier,where opal solidified from a gel (see alsoIngram, 1968).

Silcrete

The term silcrete was coined byLamplugh (1902) for 'sporadic masses inloose material of the "greyweather" type,indurated by a siliceous cement'. The termis now generally used in Australia (see Exonet al., 1970; Senior & Senior, 1972) forextremely siliceous sediments that have beensilicified during weathering. Silcrete is anextremely hard greyish rock composed ofnumerous grains of quartz, and in placeschert, set in an amorphous siliceous matrix.It breaks through grains rather than aroundthem.

Throughout the Surat Basin (as in theRoma-Amby area: Exon et al., 1970) theformation of silcrete was not restricted toanyone period. Silcrete cobbles are presentin both silicified and unsilicified sandstones.In the Eromanga Basin (B. R. Senior, pers.comm.) silcrete is younger than the deep­weathering profile, and the same generallyapplies in the Surat Basin. At several locali­ties, however, the silcrete appears to rest onthe profile, and could possibly be relatedto it.

Silcrete has been formed in siliceous sand­stones by reaction with silica-bearinggroundwater. The silica in solution was pro­bably derived mainly as a result of decom­position of clay minerals. Where the ground­water was trapped above the water-table bypermeability barriers, such as clayey beds,either during normal percolation or whenthe water-table was falling, evaporationoccurred and silica was precipitated.

Senior & Senior (1972) have described aclassic example in the Tertiary GlendowerFormation of Innamincka Dome, where asmany as three silcrete horizons, each up to

tend to weather into blocks (Fig. 49), but inbedded rocks the bedding is accentuated.

The original grainsize, distribution of rocktypes, and bedding characteristics are identi­fiable despite the deep weathering. Withinthe profile calcite has been leached and feld­spar has broken down to kaolin that formsan interstitial matrix. Iron oxides have beenformed by the alteration of grains of otheriron and ferromagnesian minerals. Resistantlithic and quartz grains are relativelyunaffected.

During the long stable period that fol­lowed Cretaceous deposition in the GreatArtesian Basin (i.e. from Late Cretaceousonward) erosion led eventually to pedi­planation. The pediplaned surface was sub­jected to a long period of weathering underconditions characterized by variable rain­fall. Constant fluctuations of the water-tableresulted in leaching in the zone of fluctua­tion, and in the development of a weatheringprofile that was very deep and probably hada resistant ferruginous capping.

In Oligocene time epeirogenic movementsbegan. They resulted in an increase in thebasinward tilt and led to some erosion of thepediplaned surface before the Oligocene­Miocene basalts were poured out over largeareas (Exon et al., 1970); more erosion fol­lowed.

Headward erosion by northerly-flowingstreams has stripped most of the deep­weathering profile and basalts from thestrongly uplifted northern part of the areawhere the land surface has been lowered inplaces by 600 m since the Miocene.

In the south, where uplift was much less,headward erosion by southwesterly-flowingstreams has been relatively less effective. Asa result large areas of deeply weatheredmaterial form plateaux along the majordivides, and mesas and buttes elsewhere.More than half the area of Cretaceous rocksexposed in the Surat Basin is deeplyweathered. The relief attributable to theresistant deeply weathered surface is con­siderable, and in the Surat Inlier the surfacelies 100 m above the surrounding streams,which are virtually at base level.

129

Thomas & Rieser (1968, p. 45) have dis­cussed the occurrence of opal in the SuratInlier, where it occurs in the deep-weather­ing profile of the Griman Creek Formation,particularly near its base. Silica-rich solu­tions, the silica coming from higher in theprofile, apparently percolated downwarduntil they came to a permeability barrier,where opal solidified from a gel (see alsoIngram, 1968).

Silcrete

The term silcrete was coined byLamplugh (1902) for 'sporadic masses inloose material of the "greyweather" type,indurated by a siliceous cement'. The termis now generally used in Australia (see Exonet al., 1970; Senior & Senior, 1972) forextremely siliceous sediments that have beensilicified during weathering. Silcrete is anextremely hard greyish rock composed ofnumerous grains of quartz, and in placeschert, set in an amorphous siliceous matrix.It breaks through grains rather than aroundthem.

Throughout the Surat Basin (as in theRoma-Amby area: Exon et al., 1970) theformation of silcrete was not restricted toanyone period. Silcrete cobbles are presentin both silicified and unsilicified sandstones.In the Eromanga Basin (B. R. Senior, pers.comm.) silcrete is younger than the deep­weathering profile, and the same generallyapplies in the Surat Basin. At several locali­ties, however, the silcrete appears to rest onthe profile, and could possibly be relatedto it.

Silcrete has been formed in siliceous sand­stones by reaction with silica-bearinggroundwater. The silica in solution was pro­bably derived mainly as a result of decom­position of clay minerals. Where the ground­water was trapped above the water-table bypermeability barriers, such as clayey beds,either during normal percolation or whenthe water-table was falling, evaporationoccurred and silica was precipitated.

Senior & Senior (1972) have described aclassic example in the Tertiary GlendowerFormation of Innamincka Dome, where asmany as three silcrete horizons, each up to

130

2 m thick, have been formed in a sequenceof siliceous sandstone about 30 m thick.

Solid silcrete horizons are rare in theSurat Basin, but the aprons of boulders andcobbles of silcrete ('grey billy') surroundingmesas indicate that it was formerly wide­spread, especially in the north. It was pro­bably concentrated predominantly in thequartzose Tertiary sandstones, most ofwhich have since been eroded away. Sili­ceous beds are forming in modern streams inthe Surat Inlier (Thomas & Reiser, 1968),and elsewhere, but the main period of for­mation of silcrete was in the mid-Tertiary,when suitable host rocks (quartzose sand­stones) were abundant.

Silcrete could have been formed in muchof Australia, when suitable quartz-rich sand­stones were exposed, and when climatic con­ditions were suitable. Favourable climaticconditions were variable rainfall, whichresulted in substantial vertical movement ofthe water-table, and warm temperatures,which resulted in relatively rapid evapora­tion of the trapped water.

To sum up it may be said that similarclimatic conditions prevailed during the for­mation of silcrete and deep-weathering pro­files, and the main difference appears to havebeen the rock type. Thus in Early Tertiarytime, when slow erosion of labile Cretaceoussediments was taking place throughout theEromanga and Surat Basins, the develop­ment of soils with deep-weathering profileswas normal. In later Tertiary times, whenquartzose sandstones were widespread, sil­crete was commonly formed as a result ofweathering.

Recent Weathering

During the Holocene erosion generallyappears to have kept pace with weathering,

and thick deep-weathering profiles have notdeveloped.

The quartzose sandstones tend to disinte­grate under the influence of weathering, butmore notable changes have taken place inthe mixed mudstone/siltstone/labile sand­stone sequences. The mixed sequences havebroken down to brown soils on the plains,although they are only slightly altered wherethe relief is greater. Carbonate, which isgenerally widespread in low concentrationsin the subsurface, has been concentrated inthe relatively rare porous beds duringweathering, in places as concretions. In thefinal stage of weathering the carbonate hasbeen replaced by iron oxide in somesequences, presumably by the oxidation ofsideritic concretions and beds.

A feature of some low-lying areas of claysoils in the development of gilgais-depres­sions formed in heavy soils of the grey clayassociation, which alternate with mounds toform a more-or-Iess complete network; thedepressions are roughly circular, up to 5 min diameter, and some are more than a metredeep. They are particularly common in theSurat Sheet area where, for example, thesoils overlying the Griman Creek Formationaround Glenmorgan are extensively 'gilgaied'(Thomas & Reiser, 1968).

Thomas & Reiser (1968) found that thegilgais were invariably associated with mont­morillonitic clays, and that they were com­monly underlain by pure quartz sand of pos­sible aeolian origin. They state that 'Themost frequently advanced explanation ofgilgais invokes the tremendous expansionand contraction of montmorillonite withalternate wetting and drying. The form ofthe gilgais . . . suggests relief of pressurethrough upward buckling in a fairly uniformbody of expanding material.'

130

2 m thick, have been formed in a sequenceof siliceous sandstone about 30 m thick.

Solid silcrete horizons are rare in theSurat Basin, but the aprons of boulders andcobbles of silcrete ('grey billy') surroundingmesas indicate that it was formerly wide­spread, especially in the north. It was pro­bably concentrated predominantly in thequartzose Tertiary sandstones, most ofwhich have since been eroded away. Sili­ceous beds are forming in modern streams inthe Surat Inlier (Thomas & Reiser, 1968),and elsewhere, but the main period of for­mation of silcrete was in the mid-Tertiary,when suitable host rocks (quartzose sand­stones) were abundant.

Silcrete could have been formed in muchof Australia, when suitable quartz-rich sand­stones were exposed, and when climatic con­ditions were suitable. Favourable climaticconditions were variable rainfall, whichresulted in substantial vertical movement ofthe water-table, and warm temperatures,which resulted in relatively rapid evapora­tion of the trapped water.

To sum up it may be said that similarclimatic conditions prevailed during the for­mation of silcrete and deep-weathering pro­files, and the main difference appears to havebeen the rock type. Thus in Early Tertiarytime, when slow erosion of labile Cretaceoussediments was taking place throughout theEromanga and Surat Basins, the develop­ment of soils with deep-weathering profileswas normal. In later Tertiary times, whenquartzose sandstones were widespread, sil­crete was commonly formed as a result ofweathering.

Recent Weathering

During the Holocene erosion generallyappears to have kept pace with weathering,

and thick deep-weathering profiles have notdeveloped.

The quartzose sandstones tend to disinte­grate under the influence of weathering, butmore notable changes have taken place inthe mixed mudstone/siltstone/labile sand­stone sequences. The mixed sequences havebroken down to brown soils on the plains,although they are only slightly altered wherethe relief is greater. Carbonate, which isgenerally widespread in low concentrationsin the subsurface, has been concentrated inthe relatively rare porous beds duringweathering, in places as concretions. In thefinal stage of weathering the carbonate hasbeen replaced by iron oxide in somesequences, presumably by the oxidation ofsideritic concretions and beds.

A feature of some low-lying areas of claysoils in the development of gilgais-depres­sions formed in heavy soils of the grey clayassociation, which alternate with mounds toform a more-or-Iess complete network; thedepressions are roughly circular, up to 5 min diameter, and some are more than a metredeep. They are particularly common in theSurat Sheet area where, for example, thesoils overlying the Griman Creek Formationaround Glenmorgan are extensively 'gilgaied'(Thomas & Reiser, 1968).

Thomas & Reiser (1968) found that thegilgais were invariably associated with mont­morillonitic clays, arid that they were com­monly underlain by pure quartz sand of pos­sible aeolian origin. They state that 'Themost frequently advanced explanation ofgilgais invokes the tremendous expansionand contraction of montmorillonite withalternate wetting and drying. The form ofthe gilgais . . . suggests relief of pressurethrough upward buckling in a fairly uniformbody of expanding material.'

131

REFERENCES* Operation subsidized under the Petroleum Search Subsidy Acts; copies available for inspection and

copying at the Bureau of Mineral Resources, Canberra and the Geological Survey of Queensland,Brisbane.

t Unpublished internal company report. Only well completion reports mentioned in the text are listed.Summaries of all wells drilled to the end of 1964 are provided in GSQ (1960-65) and later wells arelisted in DMQ (1966-74).

*AERO SERVICE CoRPORATION, 1963-Interpreta­tion report on airborne magnetometer surveyof the Surat-Bowen area, eastern Australia,for Union Oil Development Corp. (unpubl.).

ALLEN, R. J., 1961-Clay resources near Roma.Qld Govt Min. 1.,62,613-5.

ALLEN, R. J., 1971-Deep stratigraphic core drill­ing as an aid to petroleum exploration.APEA J., 11(2), 80-4.

ANDERSON, J. C., 1971-Correlation of UpperPermian strata between the Springsure Anti­cline and the Blackwater areas. Qld GovtMin. J., 72, 393-6.

BARTHOLOMAI, A., 1972-Aspects of the evolutionof the Australian marsupials. Proc. Roy. Soc.Qld, 83, v-xviii.

BARTHOLOMAI, A., 1973-The genus ProtemnodonOwen (Marsupialia: Macropodidae) in theUpper Cainozoic deposits of Queensland.Mem. Qld Mus., 16(3),309-63.

BASTIAN, L. V., 1965a-Petrological report on thebasement to Lower Jurassic sections of somesubsidised wells in the Surat Basin. Bur.Miner. Resour. Aust. Rec. 1965/120 (un­publ.) .

BASTIAN, L. V., 1965b-Petrographic notes onthe Clematis Sandstone and the MoolayemberFormation, Bowen Basin, Queensland. Ibid.,19651240 (unpubl.).

BASTIAN, L. V., 1965c-Petrographic notes on theRewan Formation, southern Bowen Basin,Queensland. Ibid., 1965/260 (unpubl.).

BASTIAN, L. V., & ARMAN, M., 1965-Petrographicnotes on some Triassic sediments in UKAWandoan No. I well and in adjoining areas.Ibid., 19651227 (unpubl.).

BOURKE, D. 1., 1974a-Completion report ofstratigraphic bore holes DM Rawdon Nos 1and lA, Surat Basin. Geol. Surv. NSW Rep.GS 1974/008 (unpubl.).

BOURKE, D. 1., 1974b-A structural subdivision ofthe Surat Basin in the Warialda area. Quart.Notes geol. Surv. NSW, 16, 1-6.

BOURKE, D. J., HAWKE, J. M., & SCHEIBNER, E.,I 974--Structural subdivision of the GreatAustralian Basin in New South Wales. Ibid.,16, 10-16.

BUCKLEY, A. W., BRADLEY, K., & ZEHNDER, J. 0.,1969-Case histories of the Moonie andAlton oilfields, Surat Basin, Queensland,Australia. Econ. Comm. Asia Far East, 4thPetrol. Symp., Canberra, 1969.

BURGER, D., 1968-Relationship of palynology tostratigraphy in the Lower Cretaceous of theSurat Basin, Queensland. Bur. Miner. Resour.Aust. Rec. 1968/125 (unpubl.).

BURGER, D., 1972-Palynological observationsfrom the Surat 1:250 000 Sheet area, withreference to GSQ Surat 1, 2 and 3 bores.Appendix I in Geol. Surv. Qld Rep. 71, 68­88.

BURGER, D., 1973-Spore zonation and sedi­mentary history in the Neocomian and earlyAptian of the Great Artesian Basin, Queens­land. Geol. Soc. Aust. spec. Publ. 4, 87-118.

BURGER, D., 1974-Palynology of subsurfaceLower Cretaceous strata in the Surat Basin,Queensland. Bur. Miner. Resour. Aust. Bull.150.

BURGER, D., 1976-Palynological papers: Part 1­Some Early Cretaceous plant microfossilsfrom Queensland. Bur. Miner. Resour. Aust.Bull. 160.

CAMERON, W. E., 1907-The West Moreton Coal­fields, Queensland. Geol. Surv. Qld Publ.204, 1-37.

CASEY, D. J., GRAY, A. R. G., & REISER, R. F.,1968-Comparison of the Lower Jurassicstrata of the Surat and Moreton Basins. QldGovt Min. J., 69, 462-5.

CONYBEARE, C. E. B., I970-Solubility andmobility of petroleum under hydrodynamicconditions, Surat Basin, Queensland. J. geol.Soc. Aust. 16(2), 667-82.

CRESPIN, Irene, 1960-Micropalaeontology ofsamples of sediments from the Great Artes­ian Basin, Queensland. Bur. Miner. Resour.Aust. Rec. 1960/25 (unpubl.).

CROOK, K. A. W., 196O-Classification of arenites.Am. J. Sci., 258, 419-28.

DAY, R. W., 1964--Stratigraphy of the Roma­Wallumbilla area. Geol. Surv. Qld Publ. 318.

DAY, R. W., 1968-Marine Lower Cretaceous fos­sils from the Minmi Member, B1ythesdaleFormation, Roma-Wallumbilla area. Ibid.,335, palaeont. Pap. 9.

DAY, R. W., 1969-Marine Lower Cretaceous ofthe Great Artesian Basin; in K. S. W.CAMPBELL, ed. STRATIGRAPHY AND PALAEON­TOLOGY; essays in honour of Dorothy Hill.Aust. Nat. Univ. Press, 140-73.

DAY, R. W., 1974-Aptian ammonites from theEromanga and Surat Basins, Queensland.Geo!. Sur. Qld. Publ. 360, palaeont. Pap. 34.

DE JERSEY, N. J., 1963-Jurassic spores andpollen grains from the Marburg Sandstone.Geol. Surv. Qld Pub!. 313.

DE JERSEY, N. J., 1968-Triassic spores and pollengrains from the Clematis Sandstone. Ibid.,338, palaeont. Pap. 14.

DE JERSEY, N. J., 1970a-Triassic miospores fromthe Blackstone Formation, Aberdare Con­glomerate and Raceview Formation. Ibid.,348, palaeont. Pap. 22.

DE JERSEY, N. J., 1970b-Early Triassic miosporesfrom the Rewan Formation. Ibid., 345,palaeont. Pap. 19.

DE JERSEY, N. J., 1971-Early Jurassic miosporesfrom the Helidon Sandstone. Ibid., 351,palaeont. Pap. 25.

131

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copying at the Bureau of Mineral Resources, Canberra and the Geological Survey of Queensland,Brisbane.

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*AERO SERVICE CoRPORATION, 1963-Interpreta­tion report on airborne magnetometer surveyof the Surat-Bowen area, eastern Australia,for Union Oil Development Corp. (unpubl.).

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ALLEN, R. J., 1971-Deep stratigraphic core drill­ing as an aid to petroleum exploration.APEA J., 11(2), 80-4.

ANDERSON, J. C., 1971-Correlation of UpperPermian strata between the Springsure Anti­cline and the Blackwater areas. Qld GovtMin. J., 72, 393-6.

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BASTIAN, L. V., 1965a-Petrological report on thebasement to Lower Jurassic sections of somesubsidised wells in the Surat Basin. Bur.Miner. Resour. Aust. Rec. 1965/120 (un­publ.) .

BASTIAN, L. V., 1965b-Petrographic notes onthe Clematis Sandstone and the MoolayemberFormation, Bowen Basin, Queensland. Ibid.,19651240 (unpubl.).

BASTIAN, L. V., 1965c-Petrographic notes on theRewan Formation, southern Bowen Basin,Queensland. Ibid., 1965/260 (unpubl.).

BASTIAN, L. V., & ARMAN, M., 1965-Petrographicnotes on some Triassic sediments in UKAWandoan No. I well and in adjoining areas.Ibid., 19651227 (unpubl.).

BOURKE, D. 1., 1974a-Completion report ofstratigraphic bore holes DM Rawdon Nos 1and lA, Surat Basin. Geol. Surv. NSW Rep.GS 1974/008 (unpubl.).

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BOURKE, D. J., HAWKE, J. M., & SCHEIBNER, E.,I 974--Structural subdivision of the GreatAustralian Basin in New South Wales. Ibid.,16, 10-16.

BUCKLEY, A. W., BRADLEY, K., & ZEHNDER, J. 0.,1969-Case histories of the Moonie andAlton oilfields, Surat Basin, Queensland,Australia. Econ. Comm. Asia Far East, 4thPetrol. Symp., Canberra, 1969.

BURGER, D., 1968-Relationship of palynology tostratigraphy in the Lower Cretaceous of theSurat Basin, Queensland. Bur. Miner. Resour.Aust. Rec. 1968/125 (unpubl.).

BURGER, D., 1972-Palynological observationsfrom the Surat 1:250 000 Sheet area, withreference to GSQ Surat 1, 2 and 3 bores.Appendix I in Geol. Surv. Qld Rep. 71, 68­88.

BURGER, D., 1973-Spore zonation and sedi­mentary history in the Neocomian and earlyAptian of the Great Artesian Basin, Queens­land. Geol. Soc. Aust. spec. Publ. 4, 87-118.

BURGER, D., 1974-Palynology of subsurfaceLower Cretaceous strata in the Surat Basin,Queensland. Bur. Miner. Resour. Aust. Bull.150.

BURGER, D., 1976-Palynological papers: Part 1­Some Early Cretaceous plant microfossilsfrom Queensland. Bur. Miner. Resour. Aust.Bull. 160.

CAMERON, W. E., 1907-The West Moreton Coal­fields, Queensland. Geol. Surv. Qld Publ.204, 1-37.

CASEY, D. J., GRAY, A. R. G., & REISER, R. F.,1968-Comparison of the Lower Jurassicstrata of the Surat and Moreton Basins. QldGovt Min. J., 69, 462-5.

CONYBEARE, C. E. B., I970-Solubility andmobility of petroleum under hydrodynamicconditions, Surat Basin, Queensland. J. geol.Soc. Aust. 16(2), 667-82.

CRESPIN, Irene, 1960-Micropalaeontology ofsamples of sediments from the Great Artes­ian Basin, Queensland. Bur. Miner. Resour.Aust. Rec. 1960/25 (unpubl.).

CROOK, K. A. W., 196O-Classification of arenites.Am. J. Sci., 258, 419-28.

DAY, R. W., 1964--Stratigraphy of the Roma­Wallumbilla area. Geol. Surv. Qld Publ. 318.

DAY, R. W., 1968-Marine Lower Cretaceous fos­sils from the Minmi Member, B1ythesdaleFormation, Roma-Wallumbilla area. Ibid.,335, palaeont. Pap. 9.

DAY, R. W., 1969-Marine Lower Cretaceous ofthe Great Artesian Basin; in K. S. W.CAMPBELL, ed. STRATIGRAPHY AND PALAEON­TOLOGY; essays in honour of Dorothy Hill.Aust. Nat. Univ. Press, 140-73.

DAY, R. W., 1974-Aptian ammonites from theEromanga and Surat Basins, Queensland.Geo!. Sur. Qld. Publ. 360, palaeont. Pap. 34.

DE JERSEY, N. J., 1963-Jurassic spores andpollen grains from the Marburg Sandstone.Geol. Surv. Qld Pub!. 313.

DE JERSEY, N. J., 1968-Triassic spores and pollengrains from the Clematis Sandstone. Ibid.,338, palaeont. Pap. 14.

DE JERSEY, N. J., 1970a-Triassic miospores fromthe Blackstone Formation, Aberdare Con­glomerate and Raceview Formation. Ibid.,348, palaeont. Pap. 22.

DE JERSEY, N. J., 1970b-Early Triassic miosporesfrom the Rewan Formation. Ibid., 345,palaeont. Pap. 19.

DE JERSEY, N. J., 1971-Early Jurassic miosporesfrom the Helidon Sandstone. Ibid., 351,palaeont. Pap. 25.

132

DE JERSEY, N. J., & ALLEN, R. J., 1966-Jurassicsource for oil of Surat-Bowen Basin, Queens­land, Australia. Bull. Am. Ass. Petrol. Geol.,50(3), 2479-81.

DE JERSEY, N. J., & HAMILTON, M., I967-Trias­sic spores and pollen grains from the Moo­layember Formation. Geol. Surv. Qld. Pub/.336, palaeont. Pap. 10.

DE JERSEY, N. J., & HAMILTON, M., 1969-Trias­sic microfossils from the Wandoan Formation.Geol. Surv. Qld Rep. 81.

DE JERSEY, N. J., & PATEN, R. J., 1964-Juras­sic spores and pollen grains from the SuratBasin. Geo/. Surv. Qld Publ. 322.

DE JERSEY, N. J., PATEN, R. J., & HAMILTON,M. A., 1964-The palynology of samplesfrom Phillips-Sunray Cecil Plains No. 1 well.Geol. Surv. Qld Rec. 1964/2 (unpubl.).

DERRINGTON, S. S., 1961-Newly named strati­graphic units in Queensland-Timbury HillsFormation, Pickanjinnie Formation. Aust. OilGas J., 7(9), 27.

DERRINGTON, S. S., GLOVER, J. J. E., & MORGAN,K. H., 1959-New names in Queenslandstratigraphy. Permian of the southeasternpart of the Bowen Syncline. Ibid., 5(8), 27-8.

DICKINS, J. M., & MALONE, E. 1., 1973-Geologyof the Bowen Basin, Queensland. Bur. Miner.Resour. Aust. Bull. 130.

DMQ (DEPARTMENT OF MINES, QUEENSLAND),1966-74-0iI drilling in Queensland; in Ann.Rep. Mines Dep. Qld, 1965-73.

DooLEY, J. C., 1950-Gravity and magneticreconnaissance, Roma district, Queensland.Bur. Miner. Resour. Aust. Bull. 18.

DUFF, P. G., & MILLIGAN, E. N., 1967-UpperJurassic bentonite from Yuleba Creek, Romadistrict. Bur. Miner. Resour. Aust. Rec.1967/9 (unpubl.).

DULHUNTY, J. A., 1939-The Mesozoic strata ofthe Merriwa-Murrurundi district and south­eastern Liverpool Plains. J. Proc. Roy. Soc.NSW, 73, 29-40.

DULHUNTY, J. A., 1968-Mesozoic strata of theNarrabri-Couradda district. Ibid., 101, 179­82.

DUNSTAN, B., 1915-ln Walkom, A., 1915. Meso­zoic floras of Queensland. Pt 1. Geol. Surv.Qld Publ. 252.

ERICKSON, R. H., 1965-Surat Basin migrationalfactors. APEA J., 5, 22-6.

EVANS, P. R, 1964-The age of the PrecipiceSandstone. Aust. J. Sci., 26, 323.

EVANS, P. R, 1966-Mesozoic stratigraphy paly­nology in Australia. Aust. Oil Gas J., 12(6),58-63.

ExON, N. F., 1966-Revised Jurassic to LowerCretaceous stratigraphy in the south-eastEromanga Basin, Queensland. Qld Govt Min.J., 67, 232-8.

EXON, N. F., 1971-Roma, Queensland-I:250 000 Geological Series. Bur. Miner.Resour. Aust. explan. Notes SG/55-12.

EXON, N. F., 1972a-Shallow stratigraphic dril­ling in the eastern Surat Basin, Queensland,1966, 1967 and 1968. Bur. Miner. Resour.Aust. Rec. 1972/54 (unpubl.).

ExON, N. F., 1972b-Sedimentation in the outerFlensburg Fjord area (Baltic Sea) since thelast glaciation. Meyniana, 22, 5-62.

EXON, N. F., 1974-The geological evolution ofthe southern Taroom Trough and the over­lying Surat Basin. APEA J., 14( I), 50-8.

EXON, N. F., & DUFF, P. G., 1968-Jurassicbentonite from the Miles district, Queensland.Bur. Miner. Resour. Aust. Rec. 1968/49(unpubl.).

EXON, N. F., GALLOWAY, M. c., CASEY, D. J., &KIRKEGAARD, A. G., 1972-Geology of theTambo/Augathella area, Queensland. Bur.Miner. Resour. Aust. Rep. 143.

EXON, N. F., LANGFORD-SMITH, T., & McDoUGALL,I., 1970-The age and geomorphic correla­tions of deep-weathering profiles, silcrete andbasalt in the Roma-Amby region, Queens­land. J. geol. Soc. Aust., 17(1), 21-30.

ExON, N. F., MILLIGAN, E. N., CASEY, D. J., &GALLOWAY, M. C., 1967-The geology ofthe Roma and Mitchell 1:250 000 Sheetareas, Queensland. Bur. Miner. Resour. Aust.Rec. 1967/63 (unpubl.).

EXON, N. F., MOND, A., REISER, R. F., & BURGER,D., 1972-The post-Palaeozoic rocks of theDalby-Goondiwindi area, Queensland andNew South Wales. Ibid., 1972/53 (unpubl.).

EXON, N. F., & MORRISSEY, J., 1974-Wireline­logging of water-bores in the Surat Basin,1960 to 1974. Bur. Miner. Resour. A list. Rec.1974/113 (unpubl.).

EXON, N. F., REISER, R. F., JENSEN, A. R,BURGER, D., & THOMAS, B. M., 1968-Thegeology of the Chinchilla 1:250000 Sheetarea, southern Queensland. Ibid., 1968/53(unpubl.).

EXON, N. F., & SENIOR, B. R, 1976-The Creta­ceous sequence of the Eromanga and SuratBasins, Quensland. BMR J. A list. Geol. Geo­phys., 1(1), 33-50.

EXON, N. F., & VINE, R. R, 1970-Revisednomenclature of the 'Blythesdale' sequence.Qld Govt Min. J., 71, 48-52.

FEHR, A., 1965-Lithological correlation of Mid­dle-Upper Triassic and Lower Jurassic unitsin seven wells in the southern Bowen-SuratBasin, Queensland. Bur. Miner. Resour. Aust.Rec. 1965/175 (unpbul.).

FEHR, A., & BASTIAN, L. V., I963-Lithologicalcorrelations of the Triassic and Lower Juras­sic in the wells Pickanjinnie 1, WinnathoolaI, Combarngo I, Sunnybank I and CabawinI (Bowen-Surat Basin). I.F.P. Mission Aust.Rep. AUS/84 (unpubl.).

*FJELSTUL, C. R., & BECK, RE., I963-Geo­physical report-reconnaissance and detailseismograph survey of western ATP71P,Queensland, Australia. For Phillips Petrol­eum Co. (unpubl.).

GALLOWAY, M. C., & DUFF, P. G., 1966-0iltraces in Lower Cretaceous sediments nearMitchell, Queensland. Aust. Oil Gas J.,12(10), 60.

GOULD, RE., 1968-The Walloon coal measures:a compilation. Qld Govt Min. J., 69.

GOULD, R. E., 1973-A new species of Osmunda­cauUs from the Jurassic of Queensland. Proc.Linn. Soc. NSW, 98(2), 86-94.

GOULD, R. E., 1974a-The fossil flora of theWalloon Coal Measures: a survey. Proc. Roy.Soc. Qld, 85(3), 33-41.

132

DE JERSEY, N. J., & ALLEN, R. J., 1966-Jurassicsource for oil of Surat-Bowen Basin, Queens­land, Australia. Bull. Am. Ass. Petrol. Geol.,50(3), 2479-81.

DE JERSEY, N. J., & HAMILTON, M., I967-Trias­sic spores and pollen grains from the Moo­layember Formation. Geol. Surv. Qld. Pub/.336, palaeont. Pap. 10.

DE JERSEY, N. J., & HAMILTON, M., 1969-Trias­sic microfossils from the Wandoan Formation.Geol. Surv. Qld Rep. 81.

DE JERSEY, N. J., & PATEN, R. J., 1964-Juras­sic spores and pollen grains from the SuratBasin. Geo/. Surv. Qld Publ. 322.

DE JERSEY, N. J., PATEN, R. J., & HAMILTON,M. A., 1964-The palynology of samplesfrom Phillips-Sunray Cecil Plains No. 1 well.Geol. Surv. Qld Rec. 1964/2 (unpubl.).

DERRINGTON, S. S., 1961-Newly named strati­graphic units in Queensland-Timbury HillsFormation, Pickanjinnie Formation. Aust. OilGas J., 7(9), 27.

DERRINGTON, S. S., GLOVER, J. J. E., & MORGAN,K. H., 1959-New names in Queenslandstratigraphy. Permian of the southeasternpart of the Bowen Syncline. Ibid., 5(8), 27-8.

DICKINS, J. M., & MALONE, E. 1., 1973-Geologyof the Bowen Basin, Queensland. Bur. Miner.Resour. Aust. Bull. 130.

DMQ (DEPARTMENT OF MINES, QUEENSLAND),1966-74-0iI drilling in Queensland; in Ann.Rep. Mines Dep. Qld, 1965-73.

DooLEY, J. C., 1950-Gravity and magneticreconnaissance, Roma district, Queensland.Bur. Miner. Resour. Aust. Bull. 18.

DUFF, P. G., & MILLIGAN, E. N., 1967-UpperJurassic bentonite from Yuleba Creek, Romadistrict. Bur. Miner. Resour. Aust. Rec.1967/9 (unpubl.).

DULHUNTY, J. A., 1939-The Mesozoic strata ofthe Merriwa-Murrurundi district and south­eastern Liverpool Plains. J. Proc. Roy. Soc.NSW, 73, 29-40.

DULHUNTY, J. A., 1968-Mesozoic strata of theNarrabri-Couradda district. Ibid., 101, 179­82.

DUNSTAN, B., 1915-ln Walkom, A., 1915. Meso­zoic floras of Queensland. Pt 1. Geol. Surv.Qld Publ. 252.

ERICKSON, R. H., 1965-Surat Basin migrationalfactors. APEA J., 5, 22-6.

EVANS, P. R, 1964-The age of the PrecipiceSandstone. Aust. J. Sci., 26, 323.

EVANS, P. R, 1966-Mesozoic stratigraphy paly­nology in Australia. Aust. Oil Gas J., 12(6),58-63.

ExON, N. F., 1966-Revised Jurassic to LowerCretaceous stratigraphy in the south-eastEromanga Basin, Queensland. Qld Govt Min.J., 67, 232-8.

EXON, N. F., 1971-Roma, Queensland-I:250 000 Geological Series. Bur. Miner.Resour. Aust. explan. Notes SG/55-12.

EXON, N. F., 1972a-Shallow stratigraphic dril­ling in the eastern Surat Basin, Queensland,1966, 1967 and 1968. Bur. Miner. Resour.Aust. Rec. 1972/54 (unpubl.).

ExON, N. F., 1972b-Sedimentation in the outerFlensburg Fjord area (Baltic Sea) since thelast glaciation. Meyniana, 22, 5-62.

EXON, N. F., 1974-The geological evolution ofthe southern Taroom Trough and the over­lying Surat Basin. APEA J., 14( I), 50-8.

EXON, N. F., & DUFF, P. G., 1968-Jurassicbentonite from the Miles district, Queensland.Bur. Miner. Resour. Aust. Rec. 1968/49(unpubl.).

EXON, N. F., GALLOWAY, M. c., CASEY, D. J., &KIRKEGAARD, A. G., 1972-Geology of theTambo/Augathella area, Queensland. Bur.Miner. Resour. Aust. Rep. 143.

EXON, N. F., LANGFORD-SMITH, T., & McDoUGALL,I., 1970-The age and geomorphic correla­tions of deep-weathering profiles, silcrete andbasalt in the Roma-Amby region, Queens­land. J. geol. Soc. Aust., 17(1), 21-30.

ExON, N. F., MILLIGAN, E. N., CASEY, D. J., &GALLOWAY, M. C., 1967-The geology ofthe Roma and Mitchell 1:250 000 Sheetareas, Queensland. Bur. Miner. Resour. Aust.Rec. 1967/63 (unpubl.).

EXON, N. F., MOND, A., REISER, R. F., & BURGER,D., 1972-The post-Palaeozoic rocks of theDalby-Goondiwindi area, Queensland andNew South Wales. Ibid., 1972/53 (unpubl.).

EXON, N. F., & MORRISSEY, J., 1974-Wireline­logging of water-bores in the Surat Basin,1960 to 1974. Bur. Miner. Resour. A list. Rec.1974/113 (unpubl.).

EXON, N. F., REISER, R. F., JENSEN, A. R,BURGER, D., & THOMAS, B. M., 1968-Thegeology of the Chinchilla 1:250000 Sheetarea, southern Queensland. Ibid., 1968/53(unpubl.).

EXON, N. F., & SENIOR, B. R, 1976-The Creta­ceous sequence of the Eromanga and SuratBasins, Quensland. BMR J. A list. Geol. Geo­phys., 1(1), 33-50.

EXON, N. F., & VINE, R. R, 1970-Revisednomenclature of the 'Blythesdale' sequence.Qld Govt Min. J., 71, 48-52.

FEHR, A., 1965-Lithological correlation of Mid­dle-Upper Triassic and Lower Jurassic unitsin seven wells in the southern Bowen-SuratBasin, Queensland. Bur. Miner. Resour. Aust.Rec. 1965/175 (unpbul.).

FEHR, A., & BASTIAN, L. V., I963-Lithologicalcorrelations of the Triassic and Lower Juras­sic in the wells Pickanjinnie 1, WinnathoolaI, Combarngo I, Sunnybank I and CabawinI (Bowen-Surat Basin). I.F.P. Mission Aust.Rep. AUS/84 (unpubl.).

*FJELSTUL, C. R., & BECK, RE., I963-Geo­physical report-reconnaissance and detailseismograph survey of western ATP71P,Queensland, Australia. For Phillips Petrol­eum Co. (unpubl.).

GALLOWAY, M. C., & DUFF, P. G., 1966-0iltraces in Lower Cretaceous sediments nearMitchell, Queensland. Aust. Oil Gas J.,12(10), 60.

GOULD, RE., 1968-The Walloon coal measures:a compilation. Qld Govt Min. J., 69.

GOULD, R. E., 1973-A new species of Osmunda­cauUs from the Jurassic of Queensland. Proc.Linn. Soc. NSW, 98(2), 86-94.

GOULD, R. E., 1974a-The fossil flora of theWalloon Coal Measures: a survey. Proc. Roy.Soc. Qld, 85(3), 33-41.

GOULD, R. E., 1974b-Report on plant fossilsfrom Durikai, southeastern Queensland.Appendix 3 in Bur. Miner. Resour. Aust.Rep. 140.

GRAVES, D. T., 1963-Moonie's significance inoil search. Qld Govt Mill. J., 64, 558-9.

GRAY. A. R. G., 1968-Stratigraphic drilling inthe Surat and Bowen Basins, 1965-66. Geol.SurI'. Qld Rep. 22.

GRAY, A. R. G., 1969-Pickanjinnie gas field.Ibid., 33.

GRAY, A. R G., 1972-Stratigraphic drilling inthe Surat and Bowen Basins, 1967-70, Ibid.,7t.

GSQ (GEOLOGICAL SURVEY OF QUEENSLAND),1960-64-0ccurrence of petroleum andnatural gas in Queensland; and supplements1-4. Geol. SurI'. Qld Pub!. 299.

HAIG, D., 1973-Lower Cretaceous Foramini­ferida, Surat Basin, southern Queensland: apreliminary stratigraphic appraisal. Qld GovtMin. J., 74, 44-52.

*HAMILTON, N. W., 1966-Amoseas Scalby No.t. Well completion report (unpubl.).

HILL, Dorothy (Ed.), 1953-Geological map ofQueensland (scale 40 miles to an inch). QldDep. Mines Publ.

HILL, Dorothy, 1957-Explanatory notes on theSpringsure 4-mile geological Sheet. Bur.Miner. Resour. Aust. Note Ser. 5.

HILL, Dorothy, & DENMEAD, A. K. (Eds), 1960­The geology of Queensland. J. geo!. Soc.Aust., 7.

HIND, M. C., & HELBY, R. J., 1969-The GreatArtesian Basin in New South Wales; Part 7in The geology of New South Wales. J. geo!.Soc. Aust., 16(1), 481-511.

HOGETOORN, D. J., 1968-Jurassic reservoirs ofthe Surat Basin. Qld Govt Min. J., 69, 256­63.

HOGETOORN, D. 1., 1970-Pine Ridge and Rasliegas fields. Geol. SurI'. Qld Rep. 55.

HousToN, Beverley R, 1964-Petrology of intru­sives of the Roma Shelf. Geol, SurI', QldRep. 7.

HousToN, Beverley, R, 1972-Petrology of sub­surface samples of Mesozoic arenites of theBowen and Surat Basins. Appendix 2 in Geol.SurI'. Qld Rep. 71, 89-98.

INGRAM, J. A., 1968-Notes on opalization insouth-western Queensland. Bur. Miner.Resour. Aust. Rec. 1968/47 (unpubl.).

ISBELL, R. F., 1955-The geology of the northernsection of the Bowen Basin. Pap. Dep. Geol.Univ. Qld, 4(11).

JACK, R L., 1895a-Artesian water in the westerninterior of Queensland. Geol. SurI'. Qld Publ.101, 1-16.

JACK, R. L., 1895b-Report of the Governmentgeologist; in Annual progress report of theGeological Survey for the year 1894. Ibid.,103, 3-24.

JACK, R. L., & MAITLAND, A. G., 1895-A geo­logical sketch map of the eastern part of theartesian water district in Queensland. Ibid ..103 (map only).

JENKINS, T. B. H., 1959-Surat (Thallon) Basin;in New names in Queensland stratigraphy(Part 4). Aust. Oil Gas J., 5(11), 29-30.

133

JENSEN, A. R., GREGORY, C. M., & FORBES, V. R.,1964-The geology of the Taroom 1:250 000Sheet area. Bur. Miner. Resour. Aust. Rec.1964/61 (unpubl.).

JENSEN, H. I., 1nl-The geology of the countrynorth of Roma. Qld Govt Min. J., 22, 91-3.

JENSEN, H. I., 1926-Geological reconnaissancebetween Roma, Springsure, Tambo andTaroom. Geo!. SurI'. Qld Publ. 277, 215.

JENSEN, H. I., 1960-Geology and oil indicationsof the Roma district. Qld geogr. J., 60, 13-20.

JONES, P. R., 1968-Lower Cretaceous (Albian)Ostracoda in BMR scout bore No. I, Surat,Surat Basin, Queensland. Appendix 3 in Bur.Miner. Resour. Aust. Rec. 1968/56 (unpubl.).59-61.

*KAHANoFF, S., 1962-Preliminary final reporton the Moree-Miles aeromagnetic survey.United Geophys. Corp. for Union Oil Devel.

. Corp. (unpubl.).KENNY, E. 1., I 928-Geological survey of the

Coonabarabran-Gunnedah district withspecial reference to the occurrence of sub­surface water. Ann. Rep. Dep. Min. NSW(1927), 130-1.

LAING, A. C. M., & ALLEN, R. J., 1955-Geologyof the Surat Authority to Prospect. MinesAdmin. Pty Ltd Rep. (unpubl.).

LAMPLUGH, G. W, 1902-Correspondence. Geo!.Mag., 4, 575

LANGFORD-SMITH, T., DURY, G. H,. & McDouGALL,I., 1966-Dating the duricrust in southernQueensland. Aust. J. Sci., 29(3), 79-80.

LONERGAN, A. D., 1973-A palynological reap­praisal of the Triassic/Jurassic boundary inthe southern Surat Basin. Geo!. SurI'. NSWRep. GS 1973/237 (unpubl.).

LUMSDEN, A. C., 1966-Condamine valleygroundwater investigations. Rep. GSQ Pro­ject E69 (unpubl.).

McDouGALL, I., & WILKINSON, J. F. G., 1967­Potassium-argon dates on some Cainozoicvolcanic rocks from northeastern New SouthWales. J, geol. Soc. Aust., 14(2), 225-34.

MACK, 1. E., Jr, 1963-Reconnaissance geology ofthe Surat Basin, Queensland and New SouthWales, Bur. Miner. Resour. Aust. Petrol.Search Subs. Acts Pub!. 40.

McTAGGART, N R., 1963-The Mesozoic sequencein the Lockyer-Marburg area, southeastQueensland. Proc. Roy. Soc. Qld, 73(7), 93­104.

MAGELLAN PETROLEUM CORP., I 963-Tambo­Augathella aeromagnetic and gravity surveys,Queensland, 1959-1960. Bur. Miner. Resour.Aust. Petrol. Search Subs. Acts Publ. 31.

MALONE, E. J., OLGERS, F., & KIRKEGAARD, A. G.,1969-The geology of the Duaringa andSaint Lawrence 1:250 000 Sheet areas,Queensland. Bur. Miner. Resour. Aust. Rep.121.

MATHEWS, R T" BURNS, B. J., & JOHNS, R. B.,1971-An approach to identification ofsource rocks. APEA J., 11(2), 115-20.

*MELLINS, I., 1971-Horrane No. 1 well comple­tion report. Amalgamated Petroleum Expl.N.L. (unpubl.).

MEYERS, N. A., 1970-Correlations and litho­facies of Jurassic sediments: Cecil Plains­Ipswich. Geol. SurI'. Qld Rep. 40.

GOULD, R. E., 1974b-Report on plant fossilsfrom Durikai, southeastern Queensland.Appendix 3 in Bur. Miner. Resour. Aust.Rep. 140.

GRAVES, D. T., 1963-Moonie's significance inoil search. Qld Govt Mill. J., 64, 558-9.

GRAY. A. R. G., 1968-Stratigraphic drilling inthe Surat and Bowen Basins, 1965-66. Geol.SurI'. Qld Rep. 22.

GRAY, A. R. G., 1969-Pickanjinnie gas field.Ibid., 33.

GRAY, A. R G., 1972-Stratigraphic drilling inthe Surat and Bowen Basins, 1967-70, Ibid.,7t.

GSQ (GEOLOGICAL SURVEY OF QUEENSLAND),1960-64-0ccurrence of petroleum andnatural gas in Queensland; and supplements1-4. Geol. SurI'. Qld Pub!. 299.

HAIG, D., 1973-Lower Cretaceous Foramini­ferida, Surat Basin, southern Queensland: apreliminary stratigraphic appraisal. Qld GovtMin. J., 74, 44-52.

*HAMILTON, N. W., 1966-Amoseas Scalby No.t. Well completion report (unpubl.).

HILL, Dorothy (Ed.), 1953-Geological map ofQueensland (scale 40 miles to an inch). QldDep. Mines Publ.

HILL, Dorothy, 1957-Explanatory notes on theSpringsure 4-mile geological Sheet. Bur.Miner. Resour. Aust. Note Ser. 5.

HILL, Dorothy, & DENMEAD, A. K. (Eds), 1960­The geology of Queensland. J. geo!. Soc.Aust., 7.

HIND, M. C., & HELBY, R. J., 1969-The GreatArtesian Basin in New South Wales; Part 7in The geology of New South Wales. J. geo!.Soc. Aust., 16(1), 481-511.

HOGETOORN, D. J., 1968-Jurassic reservoirs ofthe Surat Basin. Qld Govt Min. J., 69, 256­63.

HOGETOORN, D. 1., 1970-Pine Ridge and Rasliegas fields. Geol. SurI'. Qld Rep. 55.

HousToN, Beverley R, 1964-Petrology of intru­sives of the Roma Shelf. Geol, SurI', QldRep. 7.

HousToN, Beverley, R, 1972-Petrology of sub­surface samples of Mesozoic arenites of theBowen and Surat Basins. Appendix 2 in Geol.SurI'. Qld Rep. 71, 89-98.

INGRAM, J. A., 1968-Notes on opalization insouth-western Queensland. Bur. Miner.Resour. Aust. Rec. 1968/47 (unpubl.).

ISBELL, R. F., 1955-The geology of the northernsection of the Bowen Basin. Pap. Dep. Geol.Univ. Qld, 4(11).

JACK, R L., 1895a-Artesian water in the westerninterior of Queensland. Geol. SurI'. Qld Publ.101, 1-16.

JACK, R. L., 1895b-Report of the Governmentgeologist; in Annual progress report of theGeological Survey for the year 1894. Ibid.,103, 3-24.

JACK, R. L., & MAITLAND, A. G., 1895-A geo­logical sketch map of the eastern part of theartesian water district in Queensland. Ibid ..103 (map only).

JENKINS, T. B. H., 1959-Surat (Thallon) Basin;in New names in Queensland stratigraphy(Part 4). Aust. Oil Gas J., 5(11), 29-30.

133

JENSEN, A. R., GREGORY, C. M., & FORBES, V. R.,1964-The geology of the Taroom 1:250 000Sheet area. Bur. Miner. Resour. Aust. Rec.1964/61 (unpubl.).

JENSEN, H. I., 1nl-The geology of the countrynorth of Roma. Qld Govt Min. J., 22, 91-3.

JENSEN, H. I., 1926-Geological reconnaissancebetween Roma, Springsure, Tambo andTaroom. Geo!. SurI'. Qld Publ. 277, 215.

JENSEN, H. I., 1960-Geology and oil indicationsof the Roma district. Qld geogr. J., 60, 13-20.

JONES, P. R., 1968-Lower Cretaceous (Albian)Ostracoda in BMR scout bore No. I, Surat,Surat Basin, Queensland. Appendix 3 in Bur.Miner. Resour. Aust. Rec. 1968/56 (unpubl.).59-61.

*KAHANoFF, S., 1962-Preliminary final reporton the Moree-Miles aeromagnetic survey.United Geophys. Corp. for Union Oil Devel.

. Corp. (unpubl.).KENNY, E. 1., I 928-Geological survey of the

Coonabarabran-Gunnedah district withspecial reference to the occurrence of sub­surface water. Ann. Rep. Dep. Min. NSW(1927), 130-1.

LAING, A. C. M., & ALLEN, R. J., 1955-Geologyof the Surat Authority to Prospect. MinesAdmin. Pty Ltd Rep. (unpubl.).

LAMPLUGH, G. W, 1902-Correspondence. Geo!.Mag., 4, 575

LANGFORD-SMITH, T., DURY, G. H,. & McDouGALL,I., 1966-Dating the duricrust in southernQueensland. Aust. J. Sci., 29(3), 79-80.

LONERGAN, A. D., 1973-A palynological reap­praisal of the Triassic/Jurassic boundary inthe southern Surat Basin. Geo!. SurI'. NSWRep. GS 1973/237 (unpubl.).

LUMSDEN, A. C., 1966-Condamine valleygroundwater investigations. Rep. GSQ Pro­ject E69 (unpubl.).

McDouGALL, I., & WILKINSON, J. F. G., 1967­Potassium-argon dates on some Cainozoicvolcanic rocks from northeastern New SouthWales. J, geol. Soc. Aust., 14(2), 225-34.

MACK, 1. E., Jr, 1963-Reconnaissance geology ofthe Surat Basin, Queensland and New SouthWales, Bur. Miner. Resour. Aust. Petrol.Search Subs. Acts Pub!. 40.

McTAGGART, N R., 1963-The Mesozoic sequencein the Lockyer-Marburg area, southeastQueensland. Proc. Roy. Soc. Qld, 73(7), 93­104.

MAGELLAN PETROLEUM CORP., I 963-Tambo­Augathella aeromagnetic and gravity surveys,Queensland, 1959-1960. Bur. Miner. Resour.Aust. Petrol. Search Subs. Acts Publ. 31.

MALONE, E. J., OLGERS, F., & KIRKEGAARD, A. G.,1969-The geology of the Duaringa andSaint Lawrence 1:250 000 Sheet areas,Queensland. Bur. Miner. Resour. Aust. Rep.121.

MATHEWS, R T" BURNS, B. J., & JOHNS, R. B.,1971-An approach to identification ofsource rocks. APEA J., 11(2), 115-20.

*MELLINS, I., 1971-Horrane No. 1 well comple­tion report. Amalgamated Petroleum Expl.N.L. (unpubl.).

MEYERS, N. A., 1970-Correlations and litho­facies of Jurassic sediments: Cecil Plains­Ipswich. Geol. SurI'. Qld Rep. 40.

134

lENKINS, T. B. H., 1960-The Surat Sub-basin; inThe Geology of Queensland. I. geol. Soc.Aust. 7,315-7.

lENSEN. A. R., 1975-Permo-Triassic stratigraphyand sedimentation in the Bowen Basin,Queensland. Bur. Miner. Resol/r. Aust. Bull.154.

MILLoT, G., 1970--GEOLOGY OF CLAYS. N. Y.,Springer Verlag.

MOLI.AN, R. G., DICKINS, l. M., ExoN, N. F,. &KIRKEGAARD, A. G., 1969-Gt:Ology of theSpringsure 1:250000 Sheet area, Queensland.Bur. Miner. Resollr. Aust. Rep. 123.

MOLLAN, R. G., ExoN, N. F., & FORBES, V. R.,1965-Notes on the geology of the Eddystone1.250000 Sheet area. Bllr. Miner. Resour.Aust. Rec. 1965/98 (unpubl.).

MOLLAN, R. G., FORBES, V. R., lENSEN, A. R.,ExoN, N. F., & GREGORY, CM., 1972­Geology of the Eddystone and Taroom 1:250 000 Sheet areas and the western part ofthe Mundubbera 1:250000 Sheet area. Bllr.Miner. Resour. Aust. Rep. 142.

MOND, A., & SENIOR, B. R., 1970- ShaIlow strati­graphic drilling in the Homeboin, St George,Dirranbandi and Eulo 1:250000 Sheet areas,Queensland. Bllr. Miner. Resour. Aust. ReI'.1970/82 (unpubl.).

MORAN, W. R., & Gussow, W. C, 1963-Thehistory of the discovery and the geology ofMoonie Oil Field, Queensland, Australia. 6thWorld Petrol. Cong., Proc. geophys. geol.Sec. I, 595-609.

OGILVIE, C, 1954-The hydrology of the Queens­land portion of the Great Australian ArtesianBasin; Appendix H in Artesian water suppliesin Queensland. Dep. Co-ord. Gen. PublicWorks, Qld pari. Pap. A, 56-1955.

OLGERS, F., & FLOOD, P. G., 1974-Palaeozoicgeology of the Warwick and Goondiwindi1:250000 Sheet areas, Queensland and NewSouth Wales. Bur. Miner. Resour. Aust. Rep.164.

PATEN, R. l., I 967-Microfloral distribution inthe Lower lurassic Evergreen Formation ofthe Boxvale area, Surat Basin, Queensland.Qld Govt Min. I., 68, 345-9.

PATEN, R. J., & GROVES, R. D., 1974-Permianstratigraphy and hydrocarbon prospects of theeastern Roma Shelf. Qld Govt Min. I., 75.344-54.

PETTIJOHN, F. 1., 1957-SEDIMENTARY ROCKS.N.Y., Harper.

POWELL, T. G., & McKIRDY, D. M., 1972-Thegeochemical characterization of 'Australiancrude oils. APEA I., 12(2), 125-31.

POWELL, T. G., & McKIRDY, D. M., 1973­Relationship between ratio of pristane tophytane, crude oil composition and geologicalenvironment in Australia. Natl/re phys. Sci.,243(124), 37-9.

POWER, P. E., 1966-Australian petroleum occur­rences. A descriptive summary of BonyCreek gas field. Aust. Oil Gas I., 13(1), 24­33.

POWER, P. E., 1967-Geo10gy and hydrocarbons,Denison Trough, Australia. BIIll. Am. Ass.Petrol. Geol., 51(7), 1320-45.

POWER, P. E., & DEVINE, S. B., 1968-Some sedi­ments of the lurassic stratigraphic nomen­clature in the Great Artesian Basin. Qld GovtMin. I., 69, 194-8.

POWER, P. E., & DEVINE, S. B., I970-SuratBasin, Australia-subsurface stratigraphy,history, and petroleum. Bull. Am. Ass. Petrol.Geol., 54(12), 2410-37.

PYLE, D. E., 1967-Subsurface and reservoir con­ditions in the Moonie Oilfield. APEA I., 7,134-6.

PYLE, D. E., & BUCKLEY, A. W., 1965-Develop­ment and exploitation of the Moonie Oilfield.8th C'wealth Min. Metall. Cong., 5, 271-6.

RAGGART, H. G., 1968-MOUNTAINS OF ORE. Mel­bourne, Lansdowne Press.

REEVES, F., 1947-Geology of Roma district,Queensland, Australia. Bull. Am. Ass. Petrol.Geol., 34, 1341-71.

RElD, J. H., 1921-Geology of the Walloon-Rose­wood Coalfield. Qld Govt Min. I., 22, 223-7,264-70,310-16,357-9.

REID, J. H., 1922-Geology of the Walloon-Rose­wood Coalfield. Geol. Surv. Qld Publ. 272.

REID, J. H., 1945-The Dawson River area. QldGovt Min. I. 46, 296-9.

REISER, R F., 1970-Stratigraphic nomenclatureof the upper part of the Rolling DownsGroup in the Surat area. Qld Govt Min. I.,71,301-3.

REISER, R F., & WILLlAMS, A. l., 1969-Pa1y­nology of the Lower Jurassic sediments ofthe northern Surat Basin, Queensland. Geol.Surv. Qld Publ. 399, palaeont. Pap 15.

RICHARDS, H. C., 1918-The building stones ofQueensland. ProI'. Roy. Soc. Qld, 30, 97-157.

ROBERTSON, A. D., 1974-Intrusives in Queens­land. Appendix 1 in OLGERS & FLOOD, 1974.

SELL, B. H., BROWN, L. N., & GROVES, R. D.,1972-Basal Jurassic sands of the Roma area.Qld Govt Min. I., 73, 309-21.

SENIOR, B. R., 1970-Cainozoic tectonics andpetroleum distribution in the St George area,southern Queensland. Qld Govt Min. I., 71,476-8.

SENIOR, B. R., 1971-Structural interpretation ofthe southern Nebine Ridge area, Queensland.Aust. Oil Gas Rev. (Feb. 1971).

SENIOR, B. R., in press-Notes on the geology ofthe central part of the Eromanga Basin,Queensland. Bur. Miner. Resour. A list. Bull.167B.

SENIOR, B. R, & SENIOR, Daniele A., 1972-Sil­crete in southwest Queensland. Ibid., 125,23-8.

SHIPWAY, C. H., 1962-Roma district inspectionof basalt deposits. Geol. Surv. Qld Rep.(unpubl.).

STAINES, H. R. E., 1964-Stratigraphic nomen­clature of Bundamba Group in the Ipswicharea. Qld Govt Min. l., 65 (747), 33-5.

STEVENS, N. C, 1965-The volcanic rocks of thesouthern part of the Main Range, southeastQueensland. ProI'. Ray. Soc. Qld, 77(4).

SWARBRICK, C F. 1., 1973-Stratigraphy andeconomic potential of the Injune CreekGroup in the Surat Basin. Geal. Surv. QldRep. 79.

134

lENKINS, T. B. H., 1960-The Surat Sub-basin; inThe Geology of Queensland. I. geol. Soc.Aust. 7,315-7.

lENSEN. A. R., 1975-Permo-Triassic stratigraphyand sedimentation in the Bowen Basin,Queensland. Bur. Miner. Resol/r. Aust. Bull.154.

MILLoT, G., 1970--GEOLOGY OF CLAYS. N. Y.,Springer Verlag.

MOLI.AN, R. G., DICKINS, l. M., ExoN, N. F,. &KIRKEGAARD, A. G., 1969-Gt:Ology of theSpringsure 1:250000 Sheet area, Queensland.Bur. Miner. Resollr. Aust. Rep. 123.

MOLLAN, R. G., ExoN, N. F., & FORBES, V. R.,1965-Notes on the geology of the Eddystone1.250000 Sheet area. Bllr. Miner. Resour.Aust. Rec. 1965/98 (unpubl.).

MOLLAN, R. G., FORBES, V. R., lENSEN, A. R.,ExoN, N. F., & GREGORY, CM., 1972­Geology of the Eddystone and Taroom 1:250 000 Sheet areas and the western part ofthe Mundubbera 1:250000 Sheet area. Bllr.Miner. Resour. Aust. Rep. 142.

MOND, A., & SENIOR, B. R., 1970- ShaIlow strati­graphic drilling in the Homeboin, St George,Dirranbandi and Eulo 1:250000 Sheet areas,Queensland. Bllr. Miner. Resour. Aust. ReI'.1970/82 (unpubl.).

MORAN, W. R., & Gussow, W. C, 1963-Thehistory of the discovery and the geology ofMoonie Oil Field, Queensland, Australia. 6thWorld Petrol. Cong., Proc. geophys. geol.Sec. I, 595-609.

OGILVIE, C, 1954-The hydrology of the Queens­land portion of the Great Australian ArtesianBasin; Appendix H in Artesian water suppliesin Queensland. Dep. Co-ord. Gen. PublicWorks, Qld pari. Pap. A, 56-1955.

OLGERS, F., & FLOOD, P. G., 1974-Palaeozoicgeology of the Warwick and Goondiwindi1:250000 Sheet areas, Queensland and NewSouth Wales. Bur. Miner. Resour. Aust. Rep.164.

PATEN, R. l., I 967-Microfloral distribution inthe Lower lurassic Evergreen Formation ofthe Boxvale area, Surat Basin, Queensland.Qld Govt Min. I., 68, 345-9.

PATEN, R. J., & GROVES, R. D., 1974-Permianstratigraphy and hydrocarbon prospects of theeastern Roma Shelf. Qld Govt Min. I., 75.344-54.

PETTIJOHN, F. 1., 1957-SEDIMENTARY ROCKS.N.Y., Harper.

POWELL, T. G., & McKIRDY, D. M., 1972-Thegeochemical characterization of 'Australiancrude oils. APEA I., 12(2), 125-31.

POWELL, T. G., & McKIRDY, D. M., 1973­Relationship between ratio of pristane tophytane, crude oil composition and geologicalenvironment in Australia. Natl/re phys. Sci.,243(124), 37-9.

POWER, P. E., 1966-Australian petroleum occur­rences. A descriptive summary of BonyCreek gas field. Aust. Oil Gas I., 13(1), 24­33.

POWER, P. E., 1967-Geo10gy and hydrocarbons,Denison Trough, Australia. BIIll. Am. Ass.Petrol. Geol., 51(7), 1320-45.

POWER, P. E., & DEVINE, S. B., 1968-Some sedi­ments of the lurassic stratigraphic nomen­clature in the Great Artesian Basin. Qld GovtMin. I., 69, 194-8.

POWER, P. E., & DEVINE, S. B., I970-SuratBasin, Australia-subsurface stratigraphy,history, and petroleum. Bull. Am. Ass. Petrol.Geol., 54(12), 2410-37.

PYLE, D. E., 1967-Subsurface and reservoir con­ditions in the Moonie Oilfield. APEA I., 7,134-6.

PYLE, D. E., & BUCKLEY, A. W., 1965-Develop­ment and exploitation of the Moonie Oilfield.8th C'wealth Min. Metall. Cong., 5, 271-6.

RAGGART, H. G., 1968-MOUNTAINS OF ORE. Mel­bourne, Lansdowne Press.

REEVES, F., 1947-Geology of Roma district,Queensland, Australia. Bull. Am. Ass. Petrol.Geol., 34, 1341-71.

RElD, J. H., 1921-Geology of the Walloon-Rose­wood Coalfield. Qld Govt Min. I., 22, 223-7,264-70,310-16,357-9.

REID, J. H., 1922-Geology of the Walloon-Rose­wood Coalfield. Geol. Surv. Qld Publ. 272.

REID, J. H., 1945-The Dawson River area. QldGovt Min. I. 46, 296-9.

REISER, R F., 1970-Stratigraphic nomenclatureof the upper part of the Rolling DownsGroup in the Surat area. Qld Govt Min. I.,71,301-3.

REISER, R F., & WILLlAMS, A. l., 1969-Pa1y­nology of the Lower Jurassic sediments ofthe northern Surat Basin, Queensland. Geol.Surv. Qld Publ. 399, palaeont. Pap 15.

RICHARDS, H. C., 1918-The building stones ofQueensland. ProI'. Roy. Soc. Qld, 30, 97-157.

ROBERTSON, A. D., 1974-Intrusives in Queens­land. Appendix 1 in OLGERS & FLOOD, 1974.

SELL, B. H., BROWN, L. N., & GROVES, R. D.,1972-Basal Jurassic sands of the Roma area.Qld Govt Min. I., 73, 309-21.

SENIOR, B. R., 1970-Cainozoic tectonics andpetroleum distribution in the St George area,southern Queensland. Qld Govt Min. I., 71,476-8.

SENIOR, B. R., 1971-Structural interpretation ofthe southern Nebine Ridge area, Queensland.Aust. Oil Gas Rev. (Feb. 1971).

SENIOR, B. R., in press-Notes on the geology ofthe central part of the Eromanga Basin,Queensland. Bur. Miner. Resour. A list. Bull.167B.

SENIOR, B. R, & SENIOR, Daniele A., 1972-Sil­crete in southwest Queensland. Ibid., 125,23-8.

SHIPWAY, C. H., 1962-Roma district inspectionof basalt deposits. Geol. Surv. Qld Rep.(unpubl.).

STAINES, H. R. E., 1964-Stratigraphic nomen­clature of Bundamba Group in the Ipswicharea. Qld Govt Min. l., 65 (747), 33-5.

STEVENS, N. C, 1965-The volcanic rocks of thesouthern part of the Main Range, southeastQueensland. ProI'. Ray. Soc. Qld, 77(4).

SWARBRICK, C F. 1., 1973-Stratigraphy andeconomic potential of the Injune CreekGroup in the Surat Basin. Geal. Surv. QldRep. 79.

SWARBRICK, C. F. l., GRAY, A. R. G., & EXON,N. F., 1973-Injune Creek Group-amend­ments and an addition to stratigraphic nomen­clature in the Surat Basin. Qld Govt Min. J.,74, 57-63.

SWINDON, V. G., 1960-Marburg Sandstone ofthe type area. J. geo/. Soc. Aust., 7, 288-91.

SWINDON, V. G., 1965-Exploration methods inthe Roma area. APEA J., 5, 133-8.

SWINDON, V. G., 1968-Case history-Roma area.Ibid., 8, 120-9.

TERPSTRA, G. R. J., 1967-Micropalaeontologicalexamination of core samples from BMRMitchell No. II (scout bore). Bur. Miner.Resour. Aust. Rec. 1967/62 (unpubl.).

TERPSTRA, G. R. l., I 968-Micropalaeontologicalexamination of samples from the Surat areasubmitted by B. M. Thomas; Appendix 5 inIbid., 1968/56 (unpubl.).

TERPSTRA, G. R. J., I 969-Micropalaeontologicalexamination of cores from the Rolling DownsGroup in GSQ boreholes Surat I, 2 and 3,Queensland. Ibid., 1969/114 (unpubl.).

THOMAS, B. M., & REISER, R. F., 1968-Thegeology of the Surat 1:250000 Sheet area.Bur. Miner. Resour_ Aust. Rec. 1968/56(unpubl.).

TISSOT, B, I963--Correlations of the Permo­Triassic in the Bowen-Surat Basin. I.F.P.Miss. Aust. prog. Rep. 8, Aus/80 (unpubl.).

TRAVES, D. M., I 962-Recent developments inRoma district. Aust. Oil Gas J., 8(4),20-5.

TRAVES, D. M., 1966-Petroleum in the Roma­Springsure area. Proc. 8th Cwealth Min.metall. Cong., 5, 147-56.

TRAVES, D. M., 1971--Stratigraphic traps in theRoma area, Queensland, Australia. Proc. 8thWorld Petrol. Cong., 5(2), 275-84.

TRAVES, D. M., & THRALLS, H. M., 1960-Thegas strike at Roma. Aust. Oil Gas J., 7(2),20-3.

UNION (OIL DEVELOPMENT CORP.), 1964--Sum­mary of data and resuts, UKA Wandoan No.I and UKA Burunga No. I. Bur. Miner.Resour. Aust. Petrol. Search Subs. Acts Pub/.53.

UNION, 1965-UKA Wandoan No. I, Queens­land Ibid., 59.

*UNION & ADASTRA, I960-Final report andinterpretation of airborne magnetometer sur­vey of Surat Basin, Queensland. Union OilDevel. Corp. & Adastra Airways Pty Lld(unpubl.).

*UNITED GEOPHYSICAL CORP., 1963--Goondi­windi-St George seismic survey. Part I: Bol­lon-Dirranbandi seismic survey. For UnionOil Devel. Corp. (unpubl.).

135

URQUHART, G., 1962-Report on low grade bed­ded ironstone deposits in the Marburg-Bun­damba strata of Queensland for COllsol. ZincPty Lld Geol. Surv. Qld Rep. 840 (unpubl).

VINE, R. R., & DAY, R. W., 1965-Nomenclatureof the Rolling Downs Group, northern Ero­manga Basin. Qld Govt Mill. J., 66,416-21.

VINE, R. R., DAY, R. W., MILLlGAN, E. N., CASEY,D. 1., GALLOWAY, M. c., & EXON, N. F.,1967-Revision of the nomenclature of theRolling Downs Group in the Eromanga andSurat Basins. Qld Govt Mill. J., 68. 144-51.

WEBB, A. W.• & McDouGALL, I., 1967-A com­parison of mineral and whole rock potassium­argon ages of Tertiary volcanics from centralQueensland. Australia. Earth Plallet Sci. Left.,3, 41-7.

WEBB. A. W., & McDoUGALL. I., 1968-The geo­chronology of the igneous rocks of easternQueensland. J. geol. Soc. AlISI., 15(2), 313­47.

WEBB, A. W., STEVENS, N. C., & McDouGALL. I.,1967-Isotopic age determinations on Ter­tiary volcanic rocks and intrusives of south­east Queensland. Proc. Roy. Soc. Qld, 79(7),79-92.

WHITAKER, W. G., MURPHY, P. R., & ROLLASON,R. G., 1974-Geology of the Mundubbera1:250 000 Sheet area. Geol. Surv. Qld Rep.84.

WHITE, Mary E., 1967a-Report on 1966 collec­tions of plant fossils from the Surat Basin;southwest Eromanga Basin; Delamere, N.T.;and Proserpine district of Queensland. Bur.Miner. Resour. A liSt. Rec. 1967/68 (un­publ.).

WHITE, Mary E., 1967b-Report on 1967 collec­tion of plant fossils from Surat Basin,Queensland. Ibid., 1967/162 (unpubl).

WHITE, Mary E., 19(iQ -Report on the 1968 col­lection of plant fossils from Surat and Clar­ence-Moreton Basins, Queensland. Ibid.,1969/57 (unpubl.).

WHITEHOUSE, F. W., 1925-0n Rolling Downsfossils collected by Prof. l. W. Gregory.TrailS. Roy. Soc., S. Aust., 49, 27-36.

WHITEHOUSE, F. W., 1952-The Mesozoic environ­ments of Queensland. AlISf Ass. Adv. Sci.Rep. 29, 83-106.

WHITEHOUSE, F. W., 1954-The geology of theQueensland portion of the Great ArtesianBasin; Appendix G in Artesian water suppliesin Queensland. Dep. Co-ord. Gen. PublicWorks, Qld, pari. Pap. A, 56-1955.

WOODS, l. T., 1956-The skull of Thylaealeocami/ex. Mem. Qld Mus., 13, 177-93.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave deposits; ill The geology of Queensland.J. geol. Soc. Ausl., 7, 393-403.

WooLNOUGH, W. G., I927-The duricrust ofAustralia. J. Proc. Roy. Soc. NSW, 61, 24-53.

SWARBRICK, C. F. l., GRAY, A. R. G., & EXON,N. F., 1973-Injune Creek Group-amend­ments and an addition to stratigraphic nomen­clature in the Surat Basin. Qld Govt Min. J.,74, 57-63.

SWINDON, V. G., 1960-Marburg Sandstone ofthe type area. J. geo/. Soc. Aust., 7, 288-91.

SWINDON, V. G., 1965-Exploration methods inthe Roma area. APEA J., 5, 133-8.

SWINDON, V. G., 1968-Case history-Roma area.Ibid., 8, 120-9.

TERPSTRA, G. R. J., 1967-Micropalaeontologicalexamination of core samples from BMRMitchell No. II (scout bore). Bur. Miner.Resour. Aust. Rec. 1967/62 (unpubl.).

TERPSTRA, G. R. l., I 968-Micropalaeontologicalexamination of samples from the Surat areasubmitted by B. M. Thomas; Appendix 5 inIbid., 1968/56 (unpubl.).

TERPSTRA, G. R. J., I 969-Micropalaeontologicalexamination of cores from the Rolling DownsGroup in GSQ boreholes Surat I, 2 and 3,Queensland. Ibid., 1969/114 (unpubl.).

THOMAS, B. M., & REISER, R. F., 1968-Thegeology of the Surat 1:250000 Sheet area.Bur. Miner. Resour_ Aust. Rec. 1968/56(unpubl.).

TISSOT, B, I963--Correlations of the Permo­Triassic in the Bowen-Surat Basin. I.F.P.Miss. Aust. prog. Rep. 8, Aus/80 (unpubl.).

TRAVES, D. M., I 962-Recent developments inRoma district. Aust. Oil Gas J., 8(4),20-5.

TRAVES, D. M., 1966-Petroleum in the Roma­Springsure area. Proc. 8th Cwealth Min.metall. Cong., 5, 147-56.

TRAVES, D. M., 1971--Stratigraphic traps in theRoma area, Queensland, Australia. Proc. 8thWorld Petrol. Cong., 5(2), 275-84.

TRAVES, D. M., & THRALLS, H. M., 1960-Thegas strike at Roma. Aust. Oil Gas J., 7(2),20-3.

UNION (OIL DEVELOPMENT CORP.), 1964--Sum­mary of data and resuts, UKA Wandoan No.I and UKA Burunga No. I. Bur. Miner.Resour. Aust. Petrol. Search Subs. Acts Pub/.53.

UNION, 1965-UKA Wandoan No. I, Queens­land Ibid., 59.

*UNION & ADASTRA, I960-Final report andinterpretation of airborne magnetometer sur­vey of Surat Basin, Queensland. Union OilDevel. Corp. & Adastra Airways Pty Lld(unpubl.).

*UNITED GEOPHYSICAL CORP., 1963--Goondi­windi-St George seismic survey. Part I: Bol­lon-Dirranbandi seismic survey. For UnionOil Devel. Corp. (unpubl.).

135

URQUHART, G., 1962-Report on low grade bed­ded ironstone deposits in the Marburg-Bun­damba strata of Queensland for COllsol. ZincPty Lld Geol. Surv. Qld Rep. 840 (unpubl).

VINE, R. R., & DAY, R. W., 1965-Nomenclatureof the Rolling Downs Group, northern Ero­manga Basin. Qld Govt Mill. J., 66,416-21.

VINE, R. R., DAY, R. W., MILLlGAN, E. N., CASEY,D. 1., GALLOWAY, M. c., & EXON, N. F.,1967-Revision of the nomenclature of theRolling Downs Group in the Eromanga andSurat Basins. Qld Govt Mill. J., 68. 144-51.

WEBB, A. W.• & McDouGALL, I., 1967-A com­parison of mineral and whole rock potassium­argon ages of Tertiary volcanics from centralQueensland. Australia. Earth Plallet Sci. Left.,3, 41-7.

WEBB. A. W., & McDoUGALL. I., 1968-The geo­chronology of the igneous rocks of easternQueensland. J. geol. Soc. AlISI., 15(2), 313­47.

WEBB, A. W., STEVENS, N. C., & McDouGALL. I.,1967-Isotopic age determinations on Ter­tiary volcanic rocks and intrusives of south­east Queensland. Proc. Roy. Soc. Qld, 79(7),79-92.

WHITAKER, W. G., MURPHY, P. R., & ROLLASON,R. G., 1974-Geology of the Mundubbera1:250 000 Sheet area. Geol. Surv. Qld Rep.84.

WHITE, Mary E., 1967a-Report on 1966 collec­tions of plant fossils from the Surat Basin;southwest Eromanga Basin; Delamere, N.T.;and Proserpine district of Queensland. Bur.Miner. Resour. A liSt. Rec. 1967/68 (un­publ.).

WHITE, Mary E., 1967b-Report on 1967 collec­tion of plant fossils from Surat Basin,Queensland. Ibid., 1967/162 (unpubl).

WHITE, Mary E., 19(iQ -Report on the 1968 col­lection of plant fossils from Surat and Clar­ence-Moreton Basins, Queensland. Ibid.,1969/57 (unpubl.).

WHITEHOUSE, F. W., 1925-0n Rolling Downsfossils collected by Prof. l. W. Gregory.TrailS. Roy. Soc., S. Aust., 49, 27-36.

WHITEHOUSE, F. W., 1952-The Mesozoic environ­ments of Queensland. AlISf Ass. Adv. Sci.Rep. 29, 83-106.

WHITEHOUSE, F. W., 1954-The geology of theQueensland portion of the Great ArtesianBasin; Appendix G in Artesian water suppliesin Queensland. Dep. Co-ord. Gen. PublicWorks, Qld, pari. Pap. A, 56-1955.

WOODS, l. T., 1956-The skull of Thylaealeocami/ex. Mem. Qld Mus., 13, 177-93.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave deposits; ill The geology of Queensland.J. geol. Soc. Ausl., 7, 393-403.

WooLNOUGH, W. G., I927-The duricrust ofAustralia. J. Proc. Roy. Soc. NSW, 61, 24-53.

137

APPENDIX 1APTIAN AND ALBIAN MACROFOSSILS FROM THE MITCHELL AND ROMA

1:250 000 SHEET AREAS

byR. W. DAY

Geological Survey of QueenslandThe following work was submitted to the

Bureau of Mineral Resources as a series ofpreliminary reports in 1966 and 1967.Papers by Day (1969, 1974) embody theconclusions of these reports, which havereceived only minor editing for this publica­tion.

Map references given below apply to the20 OOO-yard transverse mercator grid shownon the 1: 250 000 Sheets.

APTIAN MACROFOSSILS FROM THE

NORTHERN HALF OF THE MITCHELL SHEET

AREA; 1965 COLLECTIONS

Of 14 collections reported here, 3 (GAB1942, 1950, and 2168) are from the MinmiMember, the remainder are from the Don­caster Member. The collections from theDoncaster Member are reported in approxi­mate ascending stratigraphic order.

MINMI MEMBER

LOCALITY:GAB1942: Tributary of Pegleg Creek, east ofthe Mitchell/Forestvale Homestead road (gridref. 618725)

Collectors:D. J. Casey, R. W. Day, M. C. Galloway

Lithology:Fine-grained glauconitic calcareous sandstone

Determinations:Maccoyella barklyi (Moore)Fissilunula clarkei (Moore)Palaeomoera? sp.'Nuculana' sp. ind.?'Nucula' sp. ind.Indet. trigonidIndet. belemnitefossil wood

Age:Aptian

LOCALITY:GAB1950: Burgagay Creek. about 0.8 kmsoutheast of where the AmbyIWalhallowHomestead road crosses (grid. ref. 645720)

Collector:D. J. Casey

Lithology:Fine-grained calcareous sandstone

Determinations:Fissilunula clarkei (Moore)Tatella maranoana (Etheridge Jnr)Lingula cf. subovalis Davidson

Age:Aptian

LOCALITY:GAB2168: Eastern tributary of Amby Creek,about 4 km west-southwest of Echo Home­stead (grid. ref. 652717)

Collector:M. C. Galloway

Lithology:Fine-grained glauconitic calcareous sandstone

Determinations:Maccoyella bark/yi (Moore)fossil wood

Age:Aptian

DoNCASTER MEMBER

LOCALITY:GAB2162: East bank of the Maranoa River,about 9.5 km north-northwest of Mitchell(grid ref. 611720)

Collector:M. C. Galloway

Lithology:Calcareous mudstone, silty limestone concre­tions, and glauconitic siltstone

Determinations:Pseudavicula anomala (Moore)Camptonectes socialis (Moore)Cyrenopsis meeki (Etheridge Jnr)Mesosacella randsi (Etheridge Jnr)Leionucula quadrata (Etheridge Jnr)Maranoana etheridgei DayLaevidentalium sp.

Age:Aptian

LOCALITY:GAB2l63: 22 m northeast of GAB2162

Collector:M. C. Galloway

Lithology:Calcareous mudstone and glauconitic siltstone

Determinations:Tropaeum leptum (Etheridge Jnr)Maccoyella barklyi (Moore)Pseudavicula anomala? (Moore)Camptonectes socialis (Moore)Mesosacella randsi (Etheridge Jnr)?Cyrenopsis sp. ind.Euspira re{lecta? (Moore)Laevidentalium sp.crinoid pinnulesfossil wood

Age:Aptian (probably late Aptian)

LOCALITY:GAB2166: Near roadside about 4 km east­northeast of Gap Plains Homestead (grid.ref. 636727)

137

APPENDIX 1APTIAN AND ALBIAN MACROFOSSILS FROM THE MITCHELL AND ROMA

1:250 000 SHEET AREAS

byR. W. DAY

Geological Survey of QueenslandThe following work was submitted to the

Bureau of Mineral Resources as a series ofpreliminary reports in 1966 and 1967.Papers by Day (1969, 1974) embody theconclusions of these reports, which havereceived only minor editing for this publica­tion.

Map references given below apply to the20 OOO-yard transverse mercator grid shownon the 1: 250 000 Sheets.

APTIAN MACROFOSSILS FROM THE

NORTHERN HALF OF THE MITCHELL SHEET

AREA; 1965 COLLECTIONS

Of 14 collections reported here, 3 (GAB1942, 1950, and 2168) are from the MinmiMember, the remainder are from the Don­caster Member. The collections from theDoncaster Member are reported in approxi­mate ascending stratigraphic order.

MINMI MEMBER

LOCALITY:GAB1942: Tributary of Pegleg Creek, east ofthe Mitchell/Forestvale Homestead road (gridref. 618725)

Collectors:D. J. Casey, R. W. Day, M. C. Galloway

Lithology:Fine-grained glauconitic calcareous sandstone

Determinations:Maccoyella barklyi (Moore)Fissilunula clarkei (Moore)Palaeomoera? sp.'Nuculana' sp. ind.?'Nucula' sp. ind.Indet. trigonidIndet. belemnitefossil wood

Age:Aptian

LOCALITY:GAB1950: Burgagay Creek. about 0.8 kmsoutheast of where the AmbyIWalhallowHomestead road crosses (grid. ref. 645720)

Collector:D. J. Casey

Lithology:Fine-grained calcareous sandstone

Determinations:Fissilunula clarkei (Moore)Tatella maranoana (Etheridge Jnr)Lingula cf. subovalis Davidson

Age:Aptian

LOCALITY:GAB2168: Eastern tributary of Amby Creek,about 4 km west-southwest of Echo Home­stead (grid. ref. 652717)

Collector:M. C. Galloway

Lithology:Fine-grained glauconitic calcareous sandstone

Determinations:Maccoyella bark/yi (Moore)fossil wood

Age:Aptian

DoNCASTER MEMBER

LOCALITY:GAB2162: East bank of the Maranoa River,about 9.5 km north-northwest of Mitchell(grid ref. 611720)

Collector:M. C. Galloway

Lithology:Calcareous mudstone, silty limestone concre­tions, and glauconitic siltstone

Determinations:Pseudavicula anomala (Moore)Camptonectes socialis (Moore)Cyrenopsis meeki (Etheridge Jnr)Mesosacella randsi (Etheridge Jnr)Leionucula quadrata (Etheridge Jnr)Maranoana etheridgei DayLaevidentalium sp.

Age:Aptian

LOCALITY:GAB2l63: 22 m northeast of GAB2162

Collector:M. C. Galloway

Lithology:Calcareous mudstone and glauconitic siltstone

Determinations:Tropaeum leptum (Etheridge Jnr)Maccoyella barklyi (Moore)Pseudavicula anomala? (Moore)Camptonectes socialis (Moore)Mesosacella randsi (Etheridge Jnr)?Cyrenopsis sp. ind.Euspira re{lecta? (Moore)Laevidentalium sp.crinoid pinnulesfossil wood

Age:Aptian (probably late Aptian)

LOCALITY:GAB2166: Near roadside about 4 km east­northeast of Gap Plains Homestead (grid.ref. 636727)

138

Collector:M. C. Galloway

Lithology:Limestone concretions and glauconitic silt­stone

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Panopea maccoyi (Moore)Onestia aff. etheridgei (Etheridge Jnr)Pholadomya sp.'Nuculana' sp. ind.?Cucullaea sp.Peratobelus sp. ind.Purisiphonia clarkei BowerbankLingula cf. subovalis Davidsonlsocrinus sp. ind.Indet. rhynchonelloid brachiopodworms burrows

Age:Aptian

LOCALITY:GAB2169: Small creek about 5 km south ofEcho Homestead (grid ref. 656713)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Lingula cf. subovalis DavidsonIndet. belemnitecrinoid brachials

Age:Aptian

LOCALITY:GAB2167: Tributary of Five Mile Creek.about 5 km east-northeast of The PeaksHomestead (grid ref. 629717)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Tropaeum or Australiceras sp. ind.Pseudavicula anomala (Moore)Maccoyella corbiensis (Moore)Cyrenopsis sp. ind.Laevidentalium sp.Lingula cf. subovalis DavidsonIndet. naticoid gastropodworm burrows

Age:Aptian

LOCALITY:GAB2156: About 8 km east of BangorHomestead (grid ref. 575734)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Panopea mooret DayIndet. rnytilid

Lingula cf. subovalis Davidsoncalcareous tubes (annelid?)

Age:Aptian

LOCALITY:GAB2155: About 5 km north of MountLonsdale Homestead (grid ref. 574732)

Collector:M. C. Galloway

Lithology:Calcareous glauconitic mudstone and siltstonewith mud pebbles

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Cyrenopsis sp. ind.ganoid? fish scale

Age:Aptian

LOCALITY:GAB1887: Back Creek, about 5 km south­southwest of Bangor Homestead (grid ref.567729)

Collector:N. Exon

Lithology:Siltstone with mud pebbles

Determinations:Maccoyella barklyi (Moore)Camptonectes socialis (Moore)Panopea moorei Daycalcareous tubes (annelid?)

Age:Aptian

LOCALITY:GAB2159: Near earth tank about 9 kmnortheast of Dulbydilla Homestead (grid ref.555731)

Collector:M. C. Galloway

Lithology:Limestone concretions

Determinations:Maccoyella sp. ind.Leionucula sp. novofossil wood

Age:Aptian

LOCALITY:GAB2098: South bank of the Maranoa River,where the river curves from the southeast tothe east-northeast, about 4 km west of Mit­chell (grid ref. 611711)

Collectors:D.1. Casey, R. W. Day. M. C. Galloway

Lithology:Calcareous concretions and silty mudstone

Determinations:Tropaeum or Australiceras sp. ind.Purisiphonia clarkei BowerbankMaccoyella barklyi (Moore)Maccoyella corbiensis (Moore)Pseudavicula anomala (Moore)'Mytilus' rugocostatus (Moore)Tancretella plana (Moore)Panopea maccoyi (Moore)

138

Collector:M. C. Galloway

Lithology:Limestone concretions and glauconitic silt­stone

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Panopea maccoyi (Moore)Onestia aff. etheridgei (Etheridge Jnr)Pholadomya sp.'Nuculana' sp. ind.?Cucullaea sp.Peratobelus sp. ind.Purisiphonia clarkei BowerbankLingula cf. subovalis Davidsonlsocrinus sp. ind.Indet. rhynchonelloid brachiopodworms burrows

Age:Aptian

LOCALITY:GAB2169: Small creek about 5 km south ofEcho Homestead (grid ref. 656713)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Lingula cf. subovalis DavidsonIndet. belemnitecrinoid brachials

Age:Aptian

LOCALITY:GAB2167: Tributary of Five Mile Creek.about 5 km east-northeast of The PeaksHomestead (grid ref. 629717)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Tropaeum or Australiceras sp. ind.Pseudavicula anomala (Moore)Maccoyella corbiensis (Moore)Cyrenopsis sp. ind.Laevidentalium sp.Lingula cf. subovalis DavidsonIndet. naticoid gastropodworm burrows

Age:Aptian

LOCALITY:GAB2156: About 8 km east of BangorHomestead (grid ref. 575734)

Collector:M. C. Galloway

Lithology:Silty limestone concretions

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Panopea mooret DayIndet. rnytilid

Lingula cf. subovalis Davidsoncalcareous tubes (annelid?)

Age:Aptian

LOCALITY:GAB2155: About 5 km north of MountLonsdale Homestead (grid ref. 574732)

Collector:M. C. Galloway

Lithology:Calcareous glauconitic mudstone and siltstonewith mud pebbles

Determinations:Maccoyella barklyi (Moore)Pseudavicula anomala (Moore)Cyrenopsis sp. ind.ganoid? fish scale

Age:Aptian

LOCALITY:GAB1887: Back Creek, about 5 km south­southwest of Bangor Homestead (grid ref.567729)

Collector:N. Exon

Lithology:Siltstone with mud pebbles

Determinations:Maccoyella barklyi (Moore)Camptonectes socialis (Moore)Panopea moorei Daycalcareous tubes (annelid?)

Age:Aptian

LOCALITY:GAB2159: Near earth tank about 9 kmnortheast of Dulbydilla Homestead (grid ref.555731)

Collector:M. C. Galloway

Lithology:Limestone concretions

Determinations:Maccoyella sp. ind.Leionucula sp. novofossil wood

Age:Aptian

LOCALITY:GAB2098: South bank of the Maranoa River,where the river curves from the southeast tothe east-northeast, about 4 km west of Mit­chell (grid ref. 611711)

Collectors:D.1. Casey, R. W. Day. M. C. Galloway

Lithology:Calcareous concretions and silty mudstone

Determinations:Tropaeum or Australiceras sp. ind.Purisiphonia clarkei BowerbankMaccoyella barklyi (Moore)Maccoyella corbiensis (Moore)Pseudavicula anomala (Moore)'Mytilus' rugocostatus (Moore)Tancretella plana (Moore)Panopea maccoyi (Moore)

Tatella maranoana (Etheridge Jnr)Inoperna ensiformis (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)Onestia aff. etheridgei (Etheridge Jnr)?'Nucula sp. ind.Euspira reflecta (Moore)Laevidentalium sp.crinoid pinnulesfossil wood

Age:Aptian

LOCALITY:GAB2152: Earth tank about 5 km east-north­east of Brunei Downs Homestead (grid ref.516739)

Collector:M. C. Galloway

Lithology:Limestone concretions

Determinations:Pseudavicula anomala (Moore)Panopea moorei DayLima randsi (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)'Gari' elliptica WhitehouseEyrena linguloides (Hudleston)Mesosacella randsi (Etheridge Jnr)Actaeon hochstetteri? (Moore)Laevidentalium sp.Lingula cf. subovalis Davidsoncrinoid brachials

Age:Aptian

REMARKS

Fossils from the three localities in theMinmi Member (GABI942, 1950, and2168) are similar to those recently reportedfrom sandstones at the base of the DoncasterMember in the Tambo area. Similarities withfaunas of the overlying Doncaster Member inthe Mitchell area, and the Minmi Memberand Doncaster Member of the Roma area,are also apparent. The pelecypods Maccoy­ella barklyi, Fissilunula clarkei, and Tatellamaranoana are common to all units. Morespecies were listed by Day (1964a, table 3)from the Minmi Member of the Roma area,than are reported here. However, the Romaarea has been more intensely collected.

Palaeomoera? sp. and the single indeter­minate trigonid reported from GAB 1942have not been observed in collections fromthe Minmi Member of the Roma area.Palaeomoera? sp. is represented at GAB1942 by numerous specimens with closedvalves. The form has a deep pallial sinus,but it is proportionately higher than theholotoype of Gari elliptica Whitehouse fig­ured by Etheridge Jnr (1901, pI. 2, fig. 8)

139

(1902, pI. 2, fig. 25) from the Lake Eyrebasin of South Australia.

The occurrence of a large specimen iden­tified as Tropaeum leptum at GAB2l63,close to the base of the WalIumbilla Forma­tion, indicates a probable late Aptian age forthis horizon. The specimen is 450 mm indiameter and lacks the initial whorls and ashort portion behind the last septum. Theornament is non-tuberculate and the ribbingis relatively uniform throughout. Althoughthe specimen has been compressed to a cer­tain extent, the whorl section is elevated likethat of the type figured by Etheridge Jnr(1909, pI. 30, figs 1-3) from Lind RiverHomestead (Carpentaria Basin). The pre­sent specimen is larger and much more com­plete than the type.

Tropaeum or Australiceras sp. ind. fromGAB2098 and 2167 are septate fragmentswith quadrate whorl sections like those ofT. australe and T. arcticum.

Ammonites are comparatively rare in theSurat Basin. Tropaeum australe (Moore,1870, pI. 15, fig. 3) from the 'Upper Mara­noa', and T. arcticum (Stolley) from 'Roma'(figured by Etheridge Jnr, 1909, pI. 32, fig.2; pI. 34, fig. 1, as Crioceras jackii) havebeen described from this area. According toCasey (1960, p. 41) the latter is very likethe English species T. subarcticum, acharacteristic ammonite of the upper Aptiannutfieldensis Zone.

The fauna in all collections from theWallumbilla Formation in the Mitchell areacorresponds closely with that of the Puri­siphonia horizon reported from the Romaarea by Day (1964a, p. 17). The species incommon include Purisiphonia clarkei,Maccoyella barklyi, M. corbiensis, Pseuda­vicula anomala, Fissilunula clarkei, Tatellamaranoana, 'Gari' elliptica, Tancretellaplana, Camptonectes socialis, lnoperna enis­form is, Eyrena linguloides, Onestia aff.etheridgei, Cyrenopsis meeki, Maranoanaetheridgei, and Mesosaccella randsi.

The brachiopod Lingula cf. subovalisoccurs quite frequently in these collections,and is from GAB1950, 2152, 2156, 2166,2167, and 2169. Curiously in the Romaarea, it was noted at only one locality(RD78).

Tatella maranoana (Etheridge Jnr)Inoperna ensiformis (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)Onestia aff. etheridgei (Etheridge Jnr)?'Nucula sp. ind.Euspira reflecta (Moore)Laevidentalium sp.crinoid pinnulesfossil wood

Age:Aptian

LOCALITY:GAB2152: Earth tank about 5 km east-north­east of Brunei Downs Homestead (grid ref.516739)

Collector:M. C. Galloway

Lithology:Limestone concretions

Determinations:Pseudavicula anomala (Moore)Panopea moorei DayLima randsi (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)'Gari' elliptica WhitehouseEyrena linguloides (Hudleston)Mesosacella randsi (Etheridge Jnr)Actaeon hochstetteri? (Moore)Laevidentalium sp.Lingula cf. subovalis Davidsoncrinoid brachials

Age:Aptian

REMARKS

Fossils from the three localities in theMinmi Member (GABI942, 1950, and2168) are similar to those recently reportedfrom sandstones at the base of the DoncasterMember in the Tambo area. Similarities withfaunas of the overlying Doncaster Member inthe Mitchell area, and the Minmi Memberand Doncaster Member of the Roma area,are also apparent. The pelecypods Maccoy­ella barklyi, Fissilunula clarkei, and Tatellamaranoana are common to all units. Morespecies were listed by Day (1964a, table 3)from the Minmi Member of the Roma area,than are reported here. However, the Romaarea has been more intensely collected.

Palaeomoera? sp. and the single indeter­minate trigonid reported from GAB 1942have not been observed in collections fromthe Minmi Member of the Roma area.Palaeomoera? sp. is represented at GAB1942 by numerous specimens with closedvalves. The form has a deep pallial sinus,but it is proportionately higher than theholotoype of Gari elliptica Whitehouse fig­ured by Etheridge Jnr (1901, pI. 2, fig. 8)

139

(1902, pI. 2, fig. 25) from the Lake Eyrebasin of South Australia.

The occurrence of a large specimen iden­tified as Tropaeum leptum at GAB2l63,close to the base of the WalIumbilla Forma­tion, indicates a probable late Aptian age forthis horizon. The specimen is 450 mm indiameter and lacks the initial whorls and ashort portion behind the last septum. Theornament is non-tuberculate and the ribbingis relatively uniform throughout. Althoughthe specimen has been compressed to a cer­tain extent, the whorl section is elevated likethat of the type figured by Etheridge Jnr(1909, pI. 30, figs 1-3) from Lind RiverHomestead (Carpentaria Basin). The pre­sent specimen is larger and much more com­plete than the type.

Tropaeum or Australiceras sp. ind. fromGAB2098 and 2167 are septate fragmentswith quadrate whorl sections like those ofT. australe and T. arcticum.

Ammonites are comparatively rare in theSurat Basin. Tropaeum australe (Moore,1870, pI. 15, fig. 3) from the 'Upper Mara­noa', and T. arcticum (Stolley) from 'Roma'(figured by Etheridge Jnr, 1909, pI. 32, fig.2; pI. 34, fig. 1, as Crioceras jackii) havebeen described from this area. According toCasey (1960, p. 41) the latter is very likethe English species T. subarcticum, acharacteristic ammonite of the upper Aptiannutfieldensis Zone.

The fauna in all collections from theWallumbilla Formation in the Mitchell areacorresponds closely with that of the Puri­siphonia horizon reported from the Romaarea by Day (1964a, p. 17). The species incommon include Purisiphonia clarkei,Maccoyella barklyi, M. corbiensis, Pseuda­vicula anomala, Fissilunula clarkei, Tatellamaranoana, 'Gari' elliptica, Tancretellaplana, Camptonectes socialis, lnoperna enis­form is, Eyrena linguloides, Onestia aff.etheridgei, Cyrenopsis meeki, Maranoanaetheridgei, and Mesosaccella randsi.

The brachiopod Lingula cf. subovalisoccurs quite frequently in these collections,and is from GAB1950, 2152, 2156, 2166,2167, and 2169. Curiously in the Romaarea, it was noted at only one locality(RD78).

140

Pholadomya sp. is represented by a smallspecimen with closed valves. Radial ribbingis very prominent on the anterior parts ofthe shell.

The Maryborough species Lima randsiEtheridge Jnr (1892, pI. 21, fig. 13) has notbeen previously reported from the Surat orEromanga Basins. Five left valves fromGAB2152 closely approach the shape andribbing of the holotype.

A MARINE FAUNA OF POSSIBLE NEOCOMIANAGE FROM THE NULLAWURT SANDSTONEMEMBER IN THE MITCHELL SHEET AREA:

1966 COLLECTIONS

LOCALITY:SB21O: 5 km west-southwest of ClaravaleHomestead (grid ref. 626746)

Lithology:Fine-grained quartzose sandstone

Determinations:Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxUnionid pelecypodscf. Purpurina ? yanreyensis Coxfossil wood

Age:Probably Neocomian

LOCALITY:SB211: 5 km west-southwest of ClaravaleHomestead (grid ref. 626747)

Lithology:Fine-grained quartzose sandstone

Determinations:Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxUnionid pelecypodsIndet. naticoid gastropod

Age:Probably Neocomian

LOCALITY:SB221: About 8 km south of Katanga Home­stead (grid ref. 639740)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxMaranoana? sp.?Tancretella sp.Leionucula aff. quadrata (Etheridge Snr)?belemnite moulds?gastropod trails

Age:Probably Neocomian

LOCALITY:SB230: About 5 km southwest of KatangaHomestead (grid ref. 635740)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxMaranoana? sp.Modiolus sp.Leionucula aff. quadrata (Etheridge Snr)worm burrowsplant fragments

Age:Probably Neocomian

LOCALITY:SB233: Near Eastern Creek, about 2.5 kmnorth of SB232 (grid ref. 619738)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.

Age:Probably Neocomian

LOCALfTY:SB239: About 4 km north of WalhallowHomestead (grid ref. 651742)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.plant fragments

Age:Probably Neocomian

REMARKSThe six collections made by N. F. Exon

from the Nullawurt Sandstone Member inthe Mitchell Sheet area provide the firstrecord of marine macrofossils in this unit.In the Roma-Wallumbilla area to the east,where the unit was first defined, Day (l964a,p. 12) reported only freshwater pelecypods,coprolites?, worm tracks and burrows, andplant fossils. In that area, the lowest strati­graphic horizon yielding a marine macro­fauna was the Minmi Member, which imme­dately overlies the Nullawurt SandstoneMember. As there are at present no recordsof post-Permian marine macrofossils in theSurat Basin, other than those from theMinmi Member and from the WallumbillaFormation, the fossils reported herein prob­ably represent the oldest Mesozoic marinemacrofauna found in the Surat Basin to date.

Occurrences of a marine fauna as well asa freshwater one in the Nullawurt SandstoneMember suggest that the member was depo­sited in near-shore environments. Themarine influence apparently did not extendas far east as the Roma-Wallumbilla area,where at present only freshwater fossils areknown.

140

Pholadomya sp. is represented by a smallspecimen with closed valves. Radial ribbingis very prominent on the anterior parts ofthe shell.

The Maryborough species Lima randsiEtheridge Jnr (1892, pI. 21, fig. 13) has notbeen previously reported from the Surat orEromanga Basins. Five left valves fromGAB2152 closely approach the shape andribbing of the holotype.

A MARINE FAUNA OF POSSIBLE NEOCOMIANAGE FROM THE NULLAWURT SANDSTONEMEMBER IN THE MITCHELL SHEET AREA:

1966 COLLECTIONS

LOCALITY:SB21O: 5 km west-southwest of ClaravaleHomestead (grid ref. 626746)

Lithology:Fine-grained quartzose sandstone

Determinations:Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxUnionid pelecypodscf. Purpurina ? yanreyensis Coxfossil wood

Age:Probably Neocomian

LOCALITY:SB211: 5 km west-southwest of ClaravaleHomestead (grid ref. 626747)

Lithology:Fine-grained quartzose sandstone

Determinations:Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxUnionid pelecypodsIndet. naticoid gastropod

Age:Probably Neocomian

LOCALITY:SB221: About 8 km south of Katanga Home­stead (grid ref. 639740)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxMaranoana? sp.?Tancretella sp.Leionucula aff. quadrata (Etheridge Snr)?belemnite moulds?gastropod trails

Age:Probably Neocomian

LOCALITY:SB230: About 5 km southwest of KatangaHomestead (grid ref. 635740)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.Tancredia sp.cf. 'Corbicellopsis' nanutarraensis CoxMaranoana? sp.Modiolus sp.Leionucula aff. quadrata (Etheridge Snr)worm burrowsplant fragments

Age:Probably Neocomian

LOCALITY:SB233: Near Eastern Creek, about 2.5 kmnorth of SB232 (grid ref. 619738)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.

Age:Probably Neocomian

LOCALfTY:SB239: About 4 km north of WalhallowHomestead (grid ref. 651742)

Lithology:Fine-grained quartzose sandstone

Determinations:Meleagrinella sp.plant fragments

Age:Probably Neocomian

REMARKSThe six collections made by N. F. Exon

from the Nullawurt Sandstone Member inthe Mitchell Sheet area provide the firstrecord of marine macrofossils in this unit.In the Roma-Wallumbilla area to the east,where the unit was first defined, Day (l964a,p. 12) reported only freshwater pelecypods,coprolites?, worm tracks and burrows, andplant fossils. In that area, the lowest strati­graphic horizon yielding a marine macro­fauna was the Minmi Member, which imme­dately overlies the Nullawurt SandstoneMember. As there are at present no recordsof post-Permian marine macrofossils in theSurat Basin, other than those from theMinmi Member and from the WallumbillaFormation, the fossils reported herein prob­ably represent the oldest Mesozoic marinemacrofauna found in the Surat Basin to date.

Occurrences of a marine fauna as well asa freshwater one in the Nullawurt SandstoneMember suggest that the member was depo­sited in near-shore environments. Themarine influence apparently did not extendas far east as the Roma-Wallumbilla area,where at present only freshwater fossils areknown.

Unfortunately, the colIections contain noammonites and it is not possible to deter­mine the age of the NulIawurt fauna withconfidence. However, from the evidenceconsidered below it is suggested that thefauna is of Neocomian age.

Neocomian affinities are displayed by thespecies from SB22l , 230, 233, and 239,which is designated Meleagrinella sp. Thisform is represented by numerous internaland external moulds of left valves and a fewright valves. In ornament and outline theyshow a close resemblance to Pseudomono/issp. figured by Whitehouse (1946, pI. 1, figs7-8) from the Neocomian (Valanginian?)Stanwell Coal Measures. The species figuredby Brunnschweiler (1960, p. 20, text-fig.15a-d, pI. 1, figs 20, 22, 25) from the earlyNeocomian Jowlaenga Formation of theDampier Peninsula, Western Australia, asMeleagrinella cf. supers/es is also similar.In addition, the single specimen describedfrom the Minmi Member by Day (1967b)as Meleagrinella sp. is comparable with thepresent form. However, alI other Melea­grinella specimens known from the MinmiMember were referred by Day (1967b) to anew species which closely resembles Pseudo­monotis superstes Spitz (1914, pI. 18, figs6-7) from the Lower Cretaceous GuiemalSandstone of the Himalayas.

Tancredia sp. from SB210, 211, 221, and230 is more transversely elongated than thenew species of Tancredia described from theMinmi Member by Day (1967b). To dateno comparable species has been observed.

A few large specimens from SB221 aredoubtfully referred to the genus TancretellaLudbrook (1966), the type species of whichis the Aptian Myacites planus Moore (1870,p. 254, pI. 12, fig. 10). In shape and mus­culature they are not unlike large formsidentified by Woods (1963) from the LauraBasin at the 'crossing of Normanby River,1.5 miles northeast of Lakefield homestead'as 'Macrocallista' sp. novo At that locality'Macrocallista' sp. novo was associated withthe presumably Neocomian (Hauterivian?)ammonite Hatchericeras lakefieldense Woods(1962).

141

Specimens from SB221 and 230 desig­nated aff. Maranoana? sp. are possibly con­generic with the Aptian species figured byEtheridge Jnr (1892, pI. 28, figs 2-5) andreferred by Day (1967b, p. 12) to a newgenus and species, Maranoana etheridgei.The NulIawurt specimen may have someaffinity with the ?Tatella sp. novo recordedby Woods (1963) from the same locality as'Macrocallista' sp. novo

In shape and to a certain extent in denti­tion, several specimens from SB210, 211,and 230 resemble an anteriorly incompletespecimen described by Cox (1961, p. 24, pI.2, figs 1Oa-b) from the Nanutarra Forma­tion of Western Australia as 'Corbicellopsis'nanutarraensis. Species of the Aptian-Albiangenus Tatella are somewhat similar in out­line, but have less prominent umbones, arenot as inflated, and lack lateral teeth. Cox(1961) assigned the Nanutarra fauna ageneral Early Cretaceous age, although S. K.Skwarko (pers. comm.) regards the age ofthe fauna as Neocomian.

A further possible link with the Nanutarrafauna is provided by two gastropods fromSB210. In coiling and ornament these arequite like Purpurina ? yanreyensis Cox(1961, p. 33, pI. 7, figs 6a-b).

Modiolus sp. is represented by a singlecarinate nondescript internal and externalmould of a left valve from SB230.

A few internal moulds of left valves fromSB221 and 230 have taxodont dentition andinternal ligament pits. They are designatedLeionucula aff. quadra/a as they resemble inshape the Aptian and Abian species des­cribed by Etheridge Snr (1872, p. 341, pI.19, fig. 5; pI. 20, fig. 3) from Maryborough.

ColIections SB210 and 211 contain num­erous medium-sized strongly inflated internaland external moulds of pelecypods withclosed valves. The shape, ornament ofcoarse concentric ribs, and the eroded con­dition of the umbones recall features welldisplayed by freshwater unionid pelecypods.They may have some relationship to'Unionid gen. & sp. nov.' reported from theRoma-Wallumbilla area by Day (1964a, p.15,table4).

Unfortunately, the colIections contain noammonites and it is not possible to deter­mine the age of the NulIawurt fauna withconfidence. However, from the evidenceconsidered below it is suggested that thefauna is of Neocomian age.

Neocomian affinities are displayed by thespecies from SB22l , 230, 233, and 239,which is designated Meleagrinella sp. Thisform is represented by numerous internaland external moulds of left valves and a fewright valves. In ornament and outline theyshow a close resemblance to Pseudomono/issp. figured by Whitehouse (1946, pI. 1, figs7-8) from the Neocomian (Valanginian?)Stanwell Coal Measures. The species figuredby Brunnschweiler (1960, p. 20, text-fig.15a-d, pI. 1, figs 20, 22, 25) from the earlyNeocomian Jowlaenga Formation of theDampier Peninsula, Western Australia, asMeleagrinella cf. supers/es is also similar.In addition, the single specimen describedfrom the Minmi Member by Day (1967b)as Meleagrinella sp. is comparable with thepresent form. However, alI other Melea­grinella specimens known from the MinmiMember were referred by Day (1967b) to anew species which closely resembles Pseudo­monotis superstes Spitz (1914, pI. 18, figs6-7) from the Lower Cretaceous GuiemalSandstone of the Himalayas.

Tancredia sp. from SB210, 211, 221, and230 is more transversely elongated than thenew species of Tancredia described from theMinmi Member by Day (1967b). To dateno comparable species has been observed.

A few large specimens from SB221 aredoubtfully referred to the genus TancretellaLudbrook (1966), the type species of whichis the Aptian Myacites planus Moore (1870,p. 254, pI. 12, fig. 10). In shape and mus­culature they are not unlike large formsidentified by Woods (1963) from the LauraBasin at the 'crossing of Normanby River,1.5 miles northeast of Lakefield homestead'as 'Macrocallista' sp. novo At that locality'Macrocallista' sp. novo was associated withthe presumably Neocomian (Hauterivian?)ammonite Hatchericeras lakefieldense Woods(1962).

141

Specimens from SB221 and 230 desig­nated aff. Maranoana? sp. are possibly con­generic with the Aptian species figured byEtheridge Jnr (1892, pI. 28, figs 2-5) andreferred by Day (1967b, p. 12) to a newgenus and species, Maranoana etheridgei.The NulIawurt specimen may have someaffinity with the ?Tatella sp. novo recordedby Woods (1963) from the same locality as'Macrocallista' sp. novo

In shape and to a certain extent in denti­tion, several specimens from SB210, 211,and 230 resemble an anteriorly incompletespecimen described by Cox (1961, p. 24, pI.2, figs 1Oa-b) from the Nanutarra Forma­tion of Western Australia as 'Corbicellopsis'nanutarraensis. Species of the Aptian-Albiangenus Tatella are somewhat similar in out­line, but have less prominent umbones, arenot as inflated, and lack lateral teeth. Cox(1961) assigned the Nanutarra fauna ageneral Early Cretaceous age, although S. K.Skwarko (pers. comm.) regards the age ofthe fauna as Neocomian.

A further possible link with the Nanutarrafauna is provided by two gastropods fromSB210. In coiling and ornament these arequite like Purpurina ? yanreyensis Cox(1961, p. 33, pI. 7, figs 6a-b).

Modiolus sp. is represented by a singlecarinate nondescript internal and externalmould of a left valve from SB230.

A few internal moulds of left valves fromSB221 and 230 have taxodont dentition andinternal ligament pits. They are designatedLeionucula aff. quadra/a as they resemble inshape the Aptian and Abian species des­cribed by Etheridge Snr (1872, p. 341, pI.19, fig. 5; pI. 20, fig. 3) from Maryborough.

ColIections SB210 and 211 contain num­erous medium-sized strongly inflated internaland external moulds of pelecypods withclosed valves. The shape, ornament ofcoarse concentric ribs, and the eroded con­dition of the umbones recall features welldisplayed by freshwater unionid pelecypods.They may have some relationship to'Unionid gen. & sp. nov.' reported from theRoma-Wallumbilla area by Day (1964a, p.15,table4).

142

Various collections also contain plantfragments, worm burrows, gastropod? trails,and belemnite? moulds.

In view of the small number of speciesrepresented in the Nullawurt fauna, and theabsence of ammonite species therein, it isdifficult to determine the age of the faunaprecisely. The difficulty is compounded bythe lack of well-documented faunas of LateJurassic to Early Cretaceous age in Austra­lia. Probably the best evidence as to age isprovided by Meleagrinella sp., whichappears to be conspecific with an unnamedspecies of Meleagrinella in the Neocomianfauna from Stanwell. This form is quite dis­tinct from the Late Jurassic species ofMeleagrinella, which are markedly multi­costate and have emarginate posterior ears.Occurrences of ?Tancretella sp. and Mara­noana ? sp. may indicate links with the Neo­comian fauna of the Laura Basin, but thisline of evidence is rather tenuous. If thespecimens from the Nullawurt SandstoneMember compared with 'Corbicellopsis'nanlltarraensis and Pllrpllrina ? yanreyensisare conspecific with those Western Austra­lian species, there is the possibility of cor­relation with the Nanutarra Formation.However, the age of the Nanutarra Forma­tion is uncertain. Leionucula aff. qlladratasuggests affinities with younger fauna, butthe Nullawurt representatives are not con­specific with this Aptian-Albian species.

Except for similarities in Meleagrinellaspecies, the fauna described by Day (l967b)from the overlying Minmi Member is quitedistinct. The single specimen of Melea­grinella sp. found in the Minmi Membermight be regarded as a remanie fossil. Theother, more commonly occurring Melea­grinella species in the Minmi Member isspecifically different. More than half thespecies in the Minmi fauna also occur in theoverlying Doncaster Member, where theyare associated with ammonites of probablelate Aptian age. The remainder of the faunacomprises new species. Only Meleagrinellawoodsi has apparent Neocomian affinities.For this reason Day (1967b) preferred anearly Aptian age for the Minmi fauna. Nega­tive evidence, from the absence of Rama

(Aptian) species, and the stratigraphicoccurrence below the Minmi fauna, suggeststhat the Nullawurt fauna is somewhat older.

Considering the evidence available at pre­sent, a Neocomian age seems the most likelypossibility, although the Nullawurt faunacannot be regarded as securely dated. A well­dated marine horizon in the NullawurtSandstone Member would be of value inplacing the Jurassic-Cretaceous boundary inthis part of the Surat Basin.

APTIAN MARINE FOSSILS FROM THE MINMIMEMBER IN THE MITCHELL AND ROMA

SHEET AREAS: 1966 COLLECTIONS

MITCHELL SHEET AREA (Collector N. F. Exon)

LOCALITY:SB200: Near road about 2.5 km southwest ofEastern Creek Homestead (grid rei. 626739)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)fossil wood fragments

Age:Aptian

LOCALITY:SB203: About 5 km northwest of NadeHomestead (grid rei. 643735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tancretella plana (Moore)Tatella maranoana (Etheridge Inr)lnoperna ensi/ormis (Etheridge Inr)

Age:Aptian

LOCALITY:SB207: About 5 km northeast of EasternCreek Homestead (grid ref. 63 1743)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tancretella plana (Moore)Tatella maranoana (Etheridge Inr)

Age:Aptian

LOCALITY:SB209: About 3 km north of Heather DownsHomestead (grid ref. 638735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tatella maranoana (Etheridge Inr)Euspira ref/ecta (Moore)

Age:Aptian

142

Various collections also contain plantfragments, worm burrows, gastropod? trails,and belemnite? moulds.

In view of the small number of speciesrepresented in the Nullawurt fauna, and theabsence of ammonite species therein, it isdifficult to determine the age of the faunaprecisely. The difficulty is compounded bythe lack of well-documented faunas of LateJurassic to Early Cretaceous age in Austra­lia. Probably the best evidence as to age isprovided by Meleagrinella sp., whichappears to be conspecific with an unnamedspecies of Meleagrinella in the Neocomianfauna from Stanwell. This form is quite dis­tinct from the Late Jurassic species ofMeleagrinella, which are markedly multi­costate and have emarginate posterior ears.Occurrences of ?Tancretella sp. and Mara­noana ? sp. may indicate links with the Neo­comian fauna of the Laura Basin, but thisline of evidence is rather tenuous. If thespecimens from the Nullawurt SandstoneMember compared with 'Corbicellopsis'nanlltarraensis and Pllrpllrina ? yanreyensisare conspecific with those Western Austra­lian species, there is the possibility of cor­relation with the Nanutarra Formation.However, the age of the Nanutarra Forma­tion is uncertain. Leionucula aff. qlladratasuggests affinities with younger fauna, butthe Nullawurt representatives are not con­specific with this Aptian-Albian species.

Except for similarities in Meleagrinellaspecies, the fauna described by Day (l967b)from the overlying Minmi Member is quitedistinct. The single specimen of Melea­grinella sp. found in the Minmi Membermight be regarded as a remanie fossil. Theother, more commonly occurring Melea­grinella species in the Minmi Member isspecifically different. More than half thespecies in the Minmi fauna also occur in theoverlying Doncaster Member, where theyare associated with ammonites of probablelate Aptian age. The remainder of the faunacomprises new species. Only Meleagrinellawoodsi has apparent Neocomian affinities.For this reason Day (1967b) preferred anearly Aptian age for the Minmi fauna. Nega­tive evidence, from the absence of Rama

(Aptian) species, and the stratigraphicoccurrence below the Minmi fauna, suggeststhat the Nullawurt fauna is somewhat older.

Considering the evidence available at pre­sent, a Neocomian age seems the most likelypossibility, although the Nullawurt faunacannot be regarded as securely dated. A well­dated marine horizon in the NullawurtSandstone Member would be of value inplacing the Jurassic-Cretaceous boundary inthis part of the Surat Basin.

APTIAN MARINE FOSSILS FROM THE MINMIMEMBER IN THE MITCHELL AND ROMA

SHEET AREAS: 1966 COLLECTIONS

MITCHELL SHEET AREA (Collector N. F. Exon)

LOCALITY:SB200: Near road about 2.5 km southwest ofEastern Creek Homestead (grid rei. 626739)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)fossil wood fragments

Age:Aptian

LOCALITY:SB203: About 5 km northwest of NadeHomestead (grid rei. 643735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tancretella plana (Moore)Tatella maranoana (Etheridge Inr)lnoperna ensi/ormis (Etheridge Inr)

Age:Aptian

LOCALITY:SB207: About 5 km northeast of EasternCreek Homestead (grid ref. 63 1743)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tancretella plana (Moore)Tatella maranoana (Etheridge Inr)

Age:Aptian

LOCALITY:SB209: About 3 km north of Heather DownsHomestead (grid ref. 638735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)Tatella maranoana (Etheridge Inr)Euspira ref/ecta (Moore)

Age:Aptian

LOCALITY:SB226: About 0.5 km northwest of KilmoreyHomestead (grid reI. 635758)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)MeleagrinelIa woodsi DayMaccoyelIa subangularis Etheridge Jnrfish scaleworm tubes

Age:Aptian

LOCALITY:SB227: About I km west of Kilmorey Home­stead (grid ref. 633758)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)Cyrenopsis balli DayInoperna ensiformis (Etheridge Jnr)MeleagrinelIa woodsi DayIndet. trigoniidEuspira re/lecta (Moore)fossil woodfish scale

Age:Aptian

LOCALITY:SB228: About 3 km southeast of KilmoreyHomestead (grid ref. 633756)

Lithology:Medium-grained glauconitic sandstone

Determinations:TancretelIa plana (Moore)Cyrenopsis balli DayMeleagrinelIa woodsi DayMaccoyelIa subangularis Etheridge Jnr'Nuculana' minmiensis DayEuspira re/lecta (Moore)

Age:Aptian

LOCALITY:SB231: On a tributary of Eastern Creek,about 5 km southwest of Eastern CreekHomestead (grid ref. 623735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)Tancredia (CorburelIa) trigoniformis DayMeleagrinella woodsi Day

Age:Aptian

LOCALITY:SB232: About 7 km east of HomeleighHomestead (grid ref. 618736)

Lithology:MedIUm to coarse-grained glauconitic sand­stone

143

Determinations:TancretelIa plana (Moore)Cyrenopsis baW DayEuspira re/lecta (Moore)

Age:Aptian

LOCALITY:SB264: Burgagay Creek, about I km south­east of where the AmbylWalhallow Home­stead road crosses (grid ref. 645720) (nearlocality GAB1950)

Lithology:Fine and medium-grained glauconitic sand­stone

Determinations:TancretelIa plana (Moore)Tatella maranoana (Etheridge Jnr)Inoperna ensiformis (Etheridge Jnr)Eyrena linguloides (Hudleston)Eyrena tatei (Etheridge Jnr)Panopea maccoyi (Moore)fish scalesfossil wood

Age:Aptian

ROMA SHEET AREA (Collector E. N.MilIigan)

LOCALITY:SB I07: Sawpit Creek, about 9 km north­northwest of Bindango Homestead (grid ref.678710)

Lithology:Fine-grained calcareous glauconitic sandstone

Determinations:Tancretella plana (Moore)Tatella maranoana (Etheridge Jnr)Maccoyella barklyi (Moore)Panopea maccoyi (Moore)

Age:Aptian

LOCALITY:SB 118: Bungeworgorai Creek, about 2.5 kmsouth of Eumina Siding (grid ref. 147706)

Lithology:Coquina band in fine-grained calcareous glau­conitic sandstone

Determinations:Peratobelus australis (Phillips)Tatella maranoana (Etheridge Jnr)Maranoana etheridgei DayMaccoyelIa barklyi (Moore)calcareous annelid tubes

Age:Aptian

LOCALITY:SB 122: About 9 km south-southwest ofLucky Downs Homestead (grid ref. 248728)

Lithology:Leached fine and medium-grained sandstone

Determinations:Tatella maranoana (Etheridge Jnr)Maranoana etheridgei DayOnestia aff. etheridgei? (Etheridge Jnr)Meleagrinella woodsi Dayfossil wood

LOCALITY:SB226: About 0.5 km northwest of KilmoreyHomestead (grid reI. 635758)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)MeleagrinelIa woodsi DayMaccoyelIa subangularis Etheridge Jnrfish scaleworm tubes

Age:Aptian

LOCALITY:SB227: About I km west of Kilmorey Home­stead (grid ref. 633758)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)Cyrenopsis balli DayInoperna ensiformis (Etheridge Jnr)MeleagrinelIa woodsi DayIndet. trigoniidEuspira re/lecta (Moore)fossil woodfish scale

Age:Aptian

LOCALITY:SB228: About 3 km southeast of KilmoreyHomestead (grid ref. 633756)

Lithology:Medium-grained glauconitic sandstone

Determinations:TancretelIa plana (Moore)Cyrenopsis balli DayMeleagrinelIa woodsi DayMaccoyelIa subangularis Etheridge Jnr'Nuculana' minmiensis DayEuspira re/lecta (Moore)

Age:Aptian

LOCALITY:SB231: On a tributary of Eastern Creek,about 5 km southwest of Eastern CreekHomestead (grid ref. 623735)

Lithology:Medium-grained glauconitic sandstone

Determinations:Fissilunula clarkei (Moore)TancretelIa plana (Moore)Tancredia (CorburelIa) trigoniformis DayMeleagrinella woodsi Day

Age:Aptian

LOCALITY:SB232: About 7 km east of HomeleighHomestead (grid ref. 618736)

Lithology:MedIUm to coarse-grained glauconitic sand­stone

143

Determinations:TancretelIa plana (Moore)Cyrenopsis baW DayEuspira re/lecta (Moore)

Age:Aptian

LOCALITY:SB264: Burgagay Creek, about I km south­east of where the AmbylWalhallow Home­stead road crosses (grid ref. 645720) (nearlocality GAB1950)

Lithology:Fine and medium-grained glauconitic sand­stone

Determinations:TancretelIa plana (Moore)Tatella maranoana (Etheridge Jnr)Inoperna ensiformis (Etheridge Jnr)Eyrena linguloides (Hudleston)Eyrena tatei (Etheridge Jnr)Panopea maccoyi (Moore)fish scalesfossil wood

Age:Aptian

ROMA SHEET AREA (Collector E. N.MilIigan)

LOCALITY:SB I07: Sawpit Creek, about 9 km north­northwest of Bindango Homestead (grid ref.678710)

Lithology:Fine-grained calcareous glauconitic sandstone

Determinations:Tancretella plana (Moore)Tatella maranoana (Etheridge Jnr)Maccoyella barklyi (Moore)Panopea maccoyi (Moore)

Age:Aptian

LOCALITY:SB 118: Bungeworgorai Creek, about 2.5 kmsouth of Eumina Siding (grid ref. 147706)

Lithology:Coquina band in fine-grained calcareous glau­conitic sandstone

Determinations:Peratobelus australis (Phillips)Tatella maranoana (Etheridge Jnr)Maranoana etheridgei DayMaccoyelIa barklyi (Moore)calcareous annelid tubes

Age:Aptian

LOCALITY:SB 122: About 9 km south-southwest ofLucky Downs Homestead (grid ref. 248728)

Lithology:Leached fine and medium-grained sandstone

Determinations:Tatella maranoana (Etheridge Jnr)Maranoana etheridgei DayOnestia aff. etheridgei? (Etheridge Jnr)Meleagrinella woodsi Dayfossil wood

144

Age:Aptian

LOCALITY:SB 124: About 19 km northeast of BendemereHomestead (grid ref. 238723)

Lithology:Leached fine-grained sandstone

Determinations:Meleagrinella woodsi DayCyrenopsis baW Day

Age:Aptian

LOCALITY:SB127: About 8 km east of Muggleton Home­stead (grid ref. 216719)

Lithology:Leached fine-grained sandstone

Determinations:Palaeomoera? sp.Meleagrinella woodsi DayPanopea maccoyi (Moore)Goniasterid starfishplant fragments

Age:Aptian

LOCALITY:SB128: About 13.5 km north-northwest ofIackson (grid ref. 243705)

Lithology:Leached fine-grained sandstone

Determinations:Tatella maranoana (Etheridge Inr)Maranoana etheridgei DayMeleagrinella woodsi Day

Age:Aptian

REMARKS

The fauna represented in these collectionsfrom the Minmi Member in the Mitchell andRoma Sheet areas is virtually identical withthat described by Day (1967b) from theMinmi Member in the Roma-Wallumbillaarea.

Most of the species also occur in the over­lying Doncaster Member of the WaIlumbillaFormation. They include the belemnite Pera­tobelus australis, the gastropod Euspirare[lecta, and the pelecypods Tatella mara­noana, Maranoana etheridgei, Palaeomoera ?sp., Tancretella plana, Fissilunula clarkei,lnoperna ensitormis, Eyrena linguloides,Eyrena tatei, Maccoyella barklyi, Maccoyellasubangularis, and Panopea maccoyi. Onestiaaff. etheridgei is known from the DoncasterMember, but it is not certain whether theMinmi Member specimens from SB122 areconspecific. Thracia primula has not beenobserved in collections from the predomin-

antly mudstone Doncaster Member, but thespecies occurs in the sandy Coreena Mem­ber which overlies the Doncaster Member.The remaining identifiable species, 'Nucu­lana' minmiensis, Tancredia (Corburella) tri­gonitormis, Cyrenopsis baW, and Melea­grinella woodsi are at present known onlyfrom the Minmi Member. Meleagrinellawoodsi has Neocomian affinities, but in viewof the preponderance of associated Aptian(Roma) species, an early Aptian age is pre­ferred for the Minmi Member.

Meleagrinella woodsi is closely related toPseudomonotis superstes Spitz (1914, pI.18, figs 6-7) from the Guiemal Sandstone ofIndia. The species has not been observed incollections from marine sandstones that con­formably underlie mudstones of the Don­caster Member in the Tambo area in theEromanga Basin. This may be due to collec­tion failure. Alternatively its absence maysuggest that the basal marine Cretaceoussandstones in the Eromanga Basin areslightly younger than the sandstones of theMinmi Member in the Mitchell and Romaareas.

'Nuculana' minmiensis has more anteriorumbones than 'Nuculana elongata' (EtheridgeSnr, 1872, pI. 20, fig. 5) and Mesosaccellarandsi (Etheridge Jnr, 1892, pI. 26, fig. 10)from the Aptian Maryborough Formation.

Cyrenopsis baW is more elongate thanother described species of that genus.

Specimens of Fissilunula clarkei, Tancre­tella plana, Tatella maranoana, and lno­perna ensitormis found in medium-grainedsandstones, do not appear to differ fromspecimens of those species collected fromfiner-grained rocks.

A single left valve from SB 127 has thesame shape as specimens identified fromSB129 in the overlying Doncaster Memberas Palaeomoera? sp.

Several rather large internal and externalmoulds from SB 122 have equilateral shapeand concentric ornament. In these respectsthey resemble the Aptian Maryborough spe­cies Onestia etheridgei (Etheridge Jnr, 1892,pI. 27, fig. 1). However, the hinge is notvisible and the identification can only betentative.

144

Age:Aptian

LOCALITY:SB 124: About 19 km northeast of BendemereHomestead (grid ref. 238723)

Lithology:Leached fine-grained sandstone

Determinations:Meleagrinella woodsi DayCyrenopsis baW Day

Age:Aptian

LOCALITY:SB127: About 8 km east of Muggleton Home­stead (grid ref. 216719)

Lithology:Leached fine-grained sandstone

Determinations:Palaeomoera? sp.Meleagrinella woodsi DayPanopea maccoyi (Moore)Goniasterid starfishplant fragments

Age:Aptian

LOCALITY:SB128: About 13.5 km north-northwest ofIackson (grid ref. 243705)

Lithology:Leached fine-grained sandstone

Determinations:Tatella maranoana (Etheridge Inr)Maranoana etheridgei DayMeleagrinella woodsi Day

Age:Aptian

REMARKS

The fauna represented in these collectionsfrom the Minmi Member in the Mitchell andRoma Sheet areas is virtually identical withthat described by Day (1967b) from theMinmi Member in the Roma-Wallumbillaarea.

Most of the species also occur in the over­lying Doncaster Member of the WaIlumbillaFormation. They include the belemnite Pera­tobelus australis, the gastropod Euspirare[lecta, and the pelecypods Tatella mara­noana, Maranoana etheridgei, Palaeomoera ?sp., Tancretella plana, Fissilunula clarkei,lnoperna ensitormis, Eyrena linguloides,Eyrena tatei, Maccoyella barklyi, Maccoyellasubangularis, and Panopea maccoyi. Onestiaaff. etheridgei is known from the DoncasterMember, but it is not certain whether theMinmi Member specimens from SB122 areconspecific. Thracia primula has not beenobserved in collections from the predomin-

antly mudstone Doncaster Member, but thespecies occurs in the sandy Coreena Mem­ber which overlies the Doncaster Member.The remaining identifiable species, 'Nucu­lana' minmiensis, Tancredia (Corburella) tri­gonitormis, Cyrenopsis baW, and Melea­grinella woodsi are at present known onlyfrom the Minmi Member. Meleagrinellawoodsi has Neocomian affinities, but in viewof the preponderance of associated Aptian(Roma) species, an early Aptian age is pre­ferred for the Minmi Member.

Meleagrinella woodsi is closely related toPseudomonotis superstes Spitz (1914, pI.18, figs 6-7) from the Guiemal Sandstone ofIndia. The species has not been observed incollections from marine sandstones that con­formably underlie mudstones of the Don­caster Member in the Tambo area in theEromanga Basin. This may be due to collec­tion failure. Alternatively its absence maysuggest that the basal marine Cretaceoussandstones in the Eromanga Basin areslightly younger than the sandstones of theMinmi Member in the Mitchell and Romaareas.

'Nuculana' minmiensis has more anteriorumbones than 'Nuculana elongata' (EtheridgeSnr, 1872, pI. 20, fig. 5) and Mesosaccellarandsi (Etheridge Jnr, 1892, pI. 26, fig. 10)from the Aptian Maryborough Formation.

Cyrenopsis baW is more elongate thanother described species of that genus.

Specimens of Fissilunula clarkei, Tancre­tella plana, Tatella maranoana, and lno­perna ensitormis found in medium-grainedsandstones, do not appear to differ fromspecimens of those species collected fromfiner-grained rocks.

A single left valve from SB 127 has thesame shape as specimens identified fromSB129 in the overlying Doncaster Memberas Palaeomoera? sp.

Several rather large internal and externalmoulds from SB 122 have equilateral shapeand concentric ornament. In these respectsthey resemble the Aptian Maryborough spe­cies Onestia etheridgei (Etheridge Jnr, 1892,pI. 27, fig. 1). However, the hinge is notvisible and the identification can only betentative.

Collection SB 128 contains an asteroidstarfish which 1S probably referrable to thefamily Goniasteridae. The arms are shortand the inter-radials of the oral surface bearridges resembling the rod-shaped ossicles ofthe Indian Jurassic genus Indiaster Rao. Thematrix 1S too coarse for ready determinationof the nature of the plates. Fragments ofstarfish arms were reported from the MinmiMember by Day (l964a).

APTIAN MACROFOSSILS FROM THEDONCASTER MEMBER IN THE MITCHELL

AND ROMA SHEET AREAS:1966 COLLECTIONS

MITCHELL SHEET AREA (Collector E. N.MilIigan)

LOCALITY:SBI04: Near the Maranoa River about2.5 km northeast of Mulgavale Homestead(grid ref. 622695)

Lithology:Fine-grained calcareous sandstone with mudpebbles

Determinations:Panopea sp.ind.plant fragments

Age:Probably Aptian

LOCALITY:SBI05: Maranoa River, about 1.5 km down­stream from Mitchell (grid ref. 617708)

Lithology:Fine-grained glauconitic silty sandstone

Determinations:Maccoyella reflecta (Moore)Maccoyella corbiensis (Moore)Cyrenopsis meeki (Etheridge Jnr)Peratobelus oxys (Tenison-Woods)?Dimitobelus sp. ind.

Age:Aptian

LOCALITY:SBI06: Sawpit Creek, about 9 km east-south­east of Mount Bindango (grid ref. 670710)

Lithology:Concretionary limestone

Determinations:Maccoyella barklyi? (Moore)Camptonectes socialis? (Moore)Tancretella plana (Moore)Lima gordoni Moorelnoperna ensiformis (Etheridge Jnr)Euspira reflecta (Moore)Peratobelus sp. ind.Purisiphonia clarkei Bowerbanklsocrinus sp. ind.algal structuresworm burrows

Age:Aptian

145

LOCALITY:SB129: Maranoa River, about 9.5 km north­northwest of Mitchell (grid ref. 611720)(locality is close to GAB2162-2163)

LithologyConcretionary limestone with some coquinabands

Determinations:Peratobelus australis (Phillips)Maccoyella barklyi (Moore)Maccoyella subangularis Etheridge JnrCamptonectes socialis (Moore)Camptonectes aequilineatus (Moore)Pseudavicula anomala? (Moore)lnoceramus cf. neocomiensis d'Orbigny'Nuculana elollgata' (Etheridge Snr)Leiollucula cooperi (Moore)Leionucula quadrata (Etheridge Snr)lnopema ellsiformis (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)'Ostrea' sp.Pallopea moorei DayThracia wilsoni MoorePalaeomoera? sp.Laevidelltalium sp.Euspira reflecta (Moore)lsocrinus sp. ind.

Age:Aptian

LOCALITY:SB130: Maranoa River, about 1.5 km down­stream from SB129 (grid ref. 609720) andabout 1 km east-northeast of Brooklyn Home­stead

Lithology:Fine-grained silty sandstone

Determillations:Leiollucula cooperi (Moore)Thracia wilsolli? Moorecrinoid fragmentsplant fragments

Age:Aptian

ROMA SHEET AREA (Collector E. N.Milligan)

LOCALITY:SBllO: Near Muckaby Creek, about 6.5 kmnorth-northeast of Bindango Siding (grid ref.734703)

Lithology:Coquina band in calcareous mudstone

Determinations:Maccoyella barklyi (Moore)llloperna ensiformis Etheridge Jnr)Fissilullula darkei? (Moore)Laevidelltalium sp.Indet. naticoid gastropodcrinoid fragments

Age:Aptian

LOCALITY:SB112: Wallumbilla Creek, about 7 kmsoutheast of Wallumbilla (grid ref. 205689)

Lithology:Fine-grained friable sandstone

Determinations:Eyrena linguloides (Hudleston)

Collection SB 128 contains an asteroidstarfish which 1S probably referrable to thefamily Goniasteridae. The arms are shortand the inter-radials of the oral surface bearridges resembling the rod-shaped ossicles ofthe Indian Jurassic genus Indiaster Rao. Thematrix 1S too coarse for ready determinationof the nature of the plates. Fragments ofstarfish arms were reported from the MinmiMember by Day (l964a).

APTIAN MACROFOSSILS FROM THEDONCASTER MEMBER IN THE MITCHELL

AND ROMA SHEET AREAS:1966 COLLECTIONS

MITCHELL SHEET AREA (Collector E. N.MilIigan)

LOCALITY:SBI04: Near the Maranoa River about2.5 km northeast of Mulgavale Homestead(grid ref. 622695)

Lithology:Fine-grained calcareous sandstone with mudpebbles

Determinations:Panopea sp.ind.plant fragments

Age:Probably Aptian

LOCALITY:SBI05: Maranoa River, about 1.5 km down­stream from Mitchell (grid ref. 617708)

Lithology:Fine-grained glauconitic silty sandstone

Determinations:Maccoyella reflecta (Moore)Maccoyella corbiensis (Moore)Cyrenopsis meeki (Etheridge Jnr)Peratobelus oxys (Tenison-Woods)?Dimitobelus sp. ind.

Age:Aptian

LOCALITY:SBI06: Sawpit Creek, about 9 km east-south­east of Mount Bindango (grid ref. 670710)

Lithology:Concretionary limestone

Determinations:Maccoyella barklyi? (Moore)Camptonectes socialis? (Moore)Tancretella plana (Moore)Lima gordoni Moorelnoperna ensiformis (Etheridge Jnr)Euspira reflecta (Moore)Peratobelus sp. ind.Purisiphonia clarkei Bowerbanklsocrinus sp. ind.algal structuresworm burrows

Age:Aptian

145

LOCALITY:SB129: Maranoa River, about 9.5 km north­northwest of Mitchell (grid ref. 611720)(locality is close to GAB2162-2163)

LithologyConcretionary limestone with some coquinabands

Determinations:Peratobelus australis (Phillips)Maccoyella barklyi (Moore)Maccoyella subangularis Etheridge JnrCamptonectes socialis (Moore)Camptonectes aequilineatus (Moore)Pseudavicula anomala? (Moore)lnoceramus cf. neocomiensis d'Orbigny'Nuculana elongata' (Etheridge Snr)Leionucula cooperi (Moore)Leionucula quadrata (Etheridge Snr)lnopema ensiformis (Etheridge Jnr)Cyrenopsis meeki (Etheridge Jnr)'Ostrea' sp.Pallopea moorei DayThracia wilsoni MoorePalaeomoera? sp.Laevidelltalium sp.Euspira reflecta (Moore)lsocrinus sp. ind.

Age:Aptian

LOCALITY:SB130: Maranoa River, about 1.5 km down­stream from SB129 (grid ref. 609720) andabout 1 km east-northeast of Brooklyn Home­stead

Lithology:Fine-grained silty sandstone

Determillations:Leionucula cooperi (Moore)Thracia wilsoni? Moorecrinoid fragmentsplant fragments

Age:Aptian

ROMA SHEET AREA (Collector E. N.Milligan)

LOCALITY:SBllO: Near Muckaby Creek, about 6.5 kmnorth-northeast of Bindango Siding (grid ref.734703)

Lithology:Coquina band in calcareous mudstone

Determinations:Maccoyella barklyi (Moore)llloperna ensiformis Etheridge Jnr)Fissilullula darkei? (Moore)Laevidelltalium sp.Indet. naticoid gastropodcrinoid fragments

Age:Aptian

LOCALITY:SB112: Wallumbilla Creek, about 7 kmsoutheast of Wallumbilla (grid ref. 205689)

Lithology:Fine-grained friable sandstone

Determinations:Eyrena linguloides (Hudleston)

146

Cyrenopsis meeki (Etheridge Jnr)'Nueulana' sp. ind.Camptoneetes sp. ind.Laevidentalium sp.Euspira refleeta (Moore)plant fragments

Age:Aptian

LOCALITY:SB114: Wallumbilla Creek, near SB112

Lithology:Fine grained friable sandstone

Determinations:Peratobelus oxys (Tenison-Woods)Inoceramus cf. neoeomiensis d'Orbigny

Age:Aptian

LOCALITY:SB115: Wallumbilla Creek, about 6.5 kmsouth-southeast of Wallumbilla (grid ref.205688)

Lithology:Concretionary limestone

Determinations:Maeeoyella sp. ind.

Age:Probably Aptian

LOCALITY:SB116: West of Wallumbilla Creek, about6.5 km south-southeast of Wallumbilla (gridref. 205690)

Lithology:Limestone concretions

Determinations:Maeeoyella refleeta (Moore)Maeeoyella umbonalis (Moore)Fissilunula clarkei (Moore)Eyrena linguloides (Hudleston)Onestia aff. etheridgei (Etheridge Jnr)'Gari' elliptiea? WhitehouseThracia wilsoni MoorePanopea maeeoyi (Moore)

Age:Aptian

LOCALITY:SB117: Wallumbilla Creek, about 7 kmsouth-southeast of Wallumbilla (grid ref.206690)

Lithology:Limestone concretions

Determinations:Peratobelus australis (Phillips)Pseudavieula anomala (Moore)Camptoneetes socialis (Moore)'Mytilus' rugoeostatus MooreTatella maranoana (Etheridge Jnr)Onestia aff. etheridgei (Etheridge Jnr)Thracia wilsoni MooreEuspira refleeta (Moore)

Age:Aptian

LOCALITY:SB119: Roma-Orallo road, about 10 km fromRoma (grid ref. 155703)

Lithology:Limestone concretions

Determinations:Pinna sp. ind.Laevidentalium sp.

Age:Probably Aptian

LOCALITY:SB120: Wallumbilla Creek, 7 km east of Bun­dilla Homestead (grid ref. 205684)

Lithology:Silty sandstone

Determinations:Panopea maeeoyi (Moore)

Age:Aptian

LOCALITY:SB121: Near where the road from Wallum­billa to the Condamine Highway crossesPickanjinnie Creek (grid ref. 200677)

Lithology:Silty sandstone

Determinations:Maecoyella refleeta (Moore)

Age:Aptian

LOCALITY:SB 123: About 5.5 km west-northwest ofPickanjinnie (grid ref. 189770)

Lithology:Silty calcareous concretions

Determinations:Tropaeum undatum? WhitehouseMaeeoyella corbiensis (Moore)Onestia aff. etheridgei (Etheridge Jnr)Euspira refleeta (Moore)Indet. belemnites'Rhynehonella'rustiea (Moore)lsoerinus allstralis (Moore)Purisiphonia clarkei Bowerbankcalcareous annelid tubes

Age:Probably late AptianIsocrinus australis (Moore)SB125: About 9 km northwest of Drillham(grid ref. 284699)

Lithology:Coquinite band in calcareous silty limestone

Determinations:Maeeoyella barklyi (Moore)Maeeoyella corbiensis (Moore)Camptoneetes socialis (Moore)Inoeeramus cf. neoeomiensis d'OrbignyLeionueula sp. ind.Indet. trigoniidsIndet. mytilidLaevidentalium sp.Euspira refleeta (Moore)Purisiphonia clarkei Bowerbanklsoerinus sp. ind.Lingula cf. sllbovalis DavidsonIndet. belemnitescalcareous annelid tubesworm burrows

Age:Aptian

LOCALITY:SB126: Dulacca Creek, about 2.5 km southof Dulacca (grid ref. 265688)

146

Cyrenopsis meeki (Etheridge Jnr)'Nueulana' sp. ind.Camptoneetes sp. ind.Laevidentalium sp.Euspira refleeta (Moore)plant fragments

Age:Aptian

LOCALITY:SB114: Wallumbilla Creek, near SB112

Lithology:Fine grained friable sandstone

Determinations:Peratobelus oxys (Tenison-Woods)Inoceramus cf. neoeomiensis d'Orbigny

Age:Aptian

LOCALITY:SB115: Wallumbilla Creek, about 6.5 kmsouth-southeast of Wallumbilla (grid ref.205688)

Lithology:Concretionary limestone

Determinations:Maeeoyella sp. ind.

Age:Probably Aptian

LOCALITY:SB116: West of Wallumbilla Creek, about6.5 km south-southeast of Wallumbilla (gridref. 205690)

Lithology:Limestone concretions

Determinations:Maeeoyella refleeta (Moore)Maeeoyella umbonalis (Moore)Fissilunula c1arkei (Moore)Eyrena Iinguloides (Hudleston)Onestia aff. etheridgei (Etheridge Jnr)'Gari' elliptiea? WhitehouseThracia wilsoni MoorePanopea maeeoyi (Moore)

Age:Aptian

LOCALITY:SB117: Wallumbilla Creek, about 7 kmsouth-southeast of Wallumbilla (grid ref.206690)

Lithology:Limestone concretions

Determinations:Peratobelus australis (Phillips)Pseudavieula anomala (Moore)Camptoneetes socialis (Moore)'Mytilus' rugoeostatus MooreTatella maranoana (Etheridge Jnr)Onestia aff. etheridgei (Etheridge Jnr)Thracia wilsoni MooreEuspira refleeta (Moore)

Age:Aptian

LOCALITY:SB119: Roma-Orallo road, about 10 km fromRoma (grid ref. 155703)

Lithology:Limestone concretions

Determinations:Pinna sp. ind.Laevidentalium sp.

Age:Probably Aptian

LOCALITY:SB120: Wallumbilla Creek, 7 km east of Bun­dilla Homestead (grid ref. 205684)

Lithology:Silty sandstone

Determinations:Panopea maeeoyi (Moore)

Age:Aptian

LOCALITY:SB121: Near where the road from Wallum­billa to the Condamine Highway crossesPickanjinnie Creek (grid ref. 200677)

Lithology:Silty sandstone

Determinations:Maecoyella refleeta (Moore)

Age:Aptian

LOCALITY:SB 123: About 5.5 km west-northwest ofPickanjinnie (grid ref. 189770)

Lithology:Silty calcareous concretions

Determinations:Tropaeum undatum? WhitehouseMaeeoyella corbiensis (Moore)Onestia aff. etheridgei (Etheridge Jnr)Euspira refleeta (Moore)Indet. belemnites'Rhynehonella'rustiea (Moore)lsoerinus allstralis (Moore)Purisiphonia c1arkei Bowerbankcalcareous annelid tubes

Age:Probably late AptianIsocrinus australis (Moore)SB125: About 9 km northwest of Drillham(grid ref. 284699)

Lithology:Coquinite band in calcareous silty limestone

Determinations:Maeeoyella barklyi (Moore)Maeeoyella corbiensis (Moore)Camptoneetes socialis (Moore)Inoeeramus cf. neoeomiensis d'OrbignyLeionueula sp. ind.Indet. trigoniidsIndet. mytilidLaevidentalium sp.Euspira refleeta (Moore)Purisiphonia c1arkei Bowerbanklsoerinus sp. ind.Lingula cf. sllbovalis DavidsonIndet. belemnitescalcareous annelid tubesworm burrows

Age:Aptian

LOCALITY:SB126: Dulacca Creek, about 2.5 km southof Dulacca (grid ref. 265688)

Lithology:Fine-grained silty sandstone

Determinations:'Lucina' sp.Lingula cf. subovalis DavidsonIndet. shell fragments

Age:Aptian

REMARKS

The vast majority of the species identifiedin the present collections from the Mitchelland Roma Sheet areas were previouslyreported from those areas by Day (1964a,(1966a). The fauna is a typical Roma(Aptian) fauna, with one possible Tamboelement. This is a single very small belem­nite guard from SB105, which may be arepresentative of the Tambo genus Dimito­belus. However, the specimen is not wellpreserved and cannot be referred with con­fidence to that genus.

Collections SBI06, SBII0, SB119,SB123, SB125, SB129, and SB130 probablybelong to the Purisiphonia horizon as theirfauna corresponds closely to that reportedby Day (1964a) from this horizon in theRoma area. The remaining collections arefrom stratigraphically higher horizons. Someof these may correspond to 'the horizon withabundant Cyrenopsis', although Cyrenopsisis not abundant in the collections.

The new collections have shown that afew species range higher than was evident incollections from the limited area mapped byDay (1964a). Numerous specimens fromSB117 indicate that the pelecypod Pseuda­vicula anomala (Moore) ranges above thePurisiphonia horizon. Pseudavicula anomalawas reported from very near the top of theAptian sequence in the Hughenden area(Day, 1964b) and from similar levels inthe Tambo and Augathella areas (Day,1966b) . Likewise, the occurrence of thebelemnite Peratobelus australis (Phillips) atSB116 indicates the range of this speciesoverlaps that of P. oxys. Several guardsfound near the top of the Aptian sequencein the Tambo area were tentatively identifiedwith P. australis by Day (I 966b). Tatellamaranoana (Etheridge Jnr) also occursabove the Purisiphonia horizon, as formslisted by Day (1964a) as Tatella? aptiana

147

Whitehouse are now regarded as conspecificwith T. maranoana.

Maccoyella refiecta (Moore) appears tobe the most characteristic fossil of strataabove the Purisiphonia horizon. The relatedM. barklyi, which has shorter ears, seems tobe confined to the lower part of the Aptiansequence. This closely parallels the situationreported by Day (1964b) in the Hughendenarea where, however, the ranges of the twospecies overlap slightly.

The only ammonite observed in these col­lections occurred at SB123, and is doubt­fully identified as Tropaeum undatum White­house. It is represented by a large bodychamber fragment with a quadrate whorlsection, and external impressions of smallerwhorls.

An unusual feature of these collections isthe occurrence of Inoceramus at SB114,SB125, and SB129. Aptian records of Ino­ceramus are quite rare. The species is anerect one with ornament not unlike that ofthe species compared with I. anglicus Woodsand I. neocomiensis d'Orbigny by Brunn­schweiller (1960). Albian species are quitedistinct.

Pinna sp. ind. represented at SB 119 by asingle incomplete specimen with closedvalves is the first Pinna the writer hasobserved in collections from the Surat Basin.The genus has previously been reportedfrom the Australian Lower Cretaceous byHudleston (1890, pI. 9, fig. 16-Pinna aus­tralis from Primrose Springs in South Aus­tralia) and by Etheridge Jnr (1892, pI. 20,figs 16-17 - Pinna sp. ind. from WalshRiver, Carpentaria Basin).

The single specimen designated 'Ostrea'sp. is the first Aptian oyster noted by thewriter. Oysters have been reported pre­viously from the Mackunda Formation inthe Manuka and Muttaburra areas.

'Nuculana elongata', which is representedby several well-preserved left and rightvalves from SB 129, is conspecific with 'Ledaelongata' Etheridge Snr (1872, pI. 20, fig. 5)from the Maryborough Formation.

Two specimens from SB129 are doubt­fully referred to the tellinid genus Palaeo­moera Stocliczka. The species were reported

Lithology:Fine-grained silty sandstone

Determinations:'Lucina' sp.Lingula cf. subovalis DavidsonIndet. shell fragments

Age:Aptian

REMARKS

The vast majority of the species identifiedin the present collections from the Mitchelland Roma Sheet areas were previouslyreported from those areas by Day (1964a,(1966a). The fauna is a typical Roma(Aptian) fauna, with one possible Tamboelement. This is a single very small belem­nite guard from SB105, which may be arepresentative of the Tambo genus Dimito­belus. However, the specimen is not wellpreserved and cannot be referred with con­fidence to that genus.

Collections SBI06, SBII0, SB119,SB123, SB125, SB129, and SB130 probablybelong to the Purisiphonia horizon as theirfauna corresponds closely to that reportedby Day (1964a) from this horizon in theRoma area. The remaining collections arefrom stratigraphically higher horizons. Someof these may correspond to 'the horizon withabundant Cyrenopsis', although Cyrenopsisis not abundant in the collections.

The new collections have shown that afew species range higher than was evident incollections from the limited area mapped byDay (1964a). Numerous specimens fromSB117 indicate that the pelecypod Pseuda­vicula anomala (Moore) ranges above thePurisiphonia horizon. Pseudavicula anomalawas reported from very near the top of theAptian sequence in the Hughenden area(Day, 1964b) and from similar levels inthe Tambo and Augathella areas (Day,1966b) . Likewise, the occurrence of thebelemnite Peratobelus australis (Phillips) atSB116 indicates the range of this speciesoverlaps that of P. oxys. Several guardsfound near the top of the Aptian sequencein the Tambo area were tentatively identifiedwith P. australis by Day (I 966b). Tatellamaranoana (Etheridge Jnr) also occursabove the Purisiphonia horizon, as formslisted by Day (1964a) as Tatella? aptiana

147

Whitehouse are now regarded as conspecificwith T. maranoana.

Maccoyella refiecta (Moore) appears tobe the most characteristic fossil of strataabove the Purisiphonia horizon. The relatedM. barklyi, which has shorter ears, seems tobe confined to the lower part of the Aptiansequence. This closely parallels the situationreported by Day (1964b) in the Hughendenarea where, however, the ranges of the twospecies overlap slightly.

The only ammonite observed in these col­lections occurred at SB123, and is doubt­fully identified as Tropaeum undatum White­house. It is represented by a large bodychamber fragment with a quadrate whorlsection, and external impressions of smallerwhorls.

An unusual feature of these collections isthe occurrence of Inoceramus at SB114,SB125, and SB129. Aptian records of Ino­ceramus are quite rare. The species is anerect one with ornament not unlike that ofthe species compared with I. anglicus Woodsand I. neocomiensis d'Orbigny by Brunn­schweiller (1960). Albian species are quitedistinct.

Pinna sp. ind. represented at SB 119 by asingle incomplete specimen with closedvalves is the first Pinna the writer hasobserved in collections from the Surat Basin.The genus has previously been reportedfrom the Australian Lower Cretaceous byHudleston (1890, pI. 9, fig. 16-Pinna aus­tralis from Primrose Springs in South Aus­tralia) and by Etheridge Jnr (1892, pI. 20,figs 16-17 - Pinna sp. ind. from WalshRiver, Carpentaria Basin).

The single specimen designated 'Ostrea'sp. is the first Aptian oyster noted by thewriter. Oysters have been reported pre­viously from the Mackunda Formation inthe Manuka and Muttaburra areas.

'Nuculana elongata', which is representedby several well-preserved left and rightvalves from SB 129, is conspecific with 'Ledaelongata' Etheridge Snr (1872, pI. 20, fig. 5)from the Maryborough Formation.

Two specimens from SB129 are doubt­fully referred to the tellinid genus Palaeo­moera Stocliczka. The species were reported

148

from GAB 1942 in the Minmi Member ofthe Mitchell area and from GAB 1134 in theDoncaster Member of the Hughenden areaas Tatella aft. maranoana (Etheridge Jnr).In outline the species resembles 'Gari' ellip­tica, but the umbones are centrally placedand the species is proportionately higherthan 'G' elliptica. Tellina sp. figured byEtheridge Snr (1872, pI. 20, fig. 7) fromMaryborough may be related.

Collection SB 125 contains several speci­mens of the crinoid Isocrinus australis(Moore) and the sponge Purisiphoniaclarkei Bowerbank in positions of growth.Associated with these are the brachiopods'Rhynchonella' rustica Moore (1870, p. 245,pI. 10, figs 7-9) and 'A rgyope' wallumbil­laensis Moore (1870, p. 243, pI. 10, figs3-5). Brachiopods are not common in theAptian sequence and are even rarer in theAlbian.

ALBIAN FOSSILS FROM THE COREENA MEM­BER IN THE SURAT BASIN: 1966

COLLECTIONS

The seven collections reported below pro­vide the first record of Albian macrofossilsin the Surat Basin. Two of the collectionsare from the Roma Sheet area, the remain­der from the Mitchell Sheet area.

MITCHELL SHEET AREA (Collector E. N.MiIligan)

LOCALITY:SBIOO: Near tributary of Emu Creek, about5 km east of Mount Abundance (grid ref.668684)

Lithology:'Belemnite conglomerate' in cross-laminatedglauconitic siltstone

Determinations:Dimitobellls diptychlls (McCoy)Peratobellls sp. novoIndet. pelecypod

Age:Early Albian

LOCALITY:SB 101: Near tributary of Emu Creek, about3 km east of Mount Abundance (grid ref.667685)

Lithology:Coquina bands in calcareous siltstone

Determinations:AlIcellina hllghendenensis (Etheridge Snr)Barcoona trigonalis (Moore)Maccoyella corbiensis (Moore)Mesosaccella randsi (Etheridge Jnr)

'Yoldia' freytagi LudbrookElIspira reflecta (Moore)Indet. belemnite

Age:Probably early Albian

LOCALITY:SB 102: East of where road crosses BackCreek, about 6.5 km north of Amby (gridref. 638708)

Lithology:Siltstone

Determinations:Dimitobellls diptychus (McCoy)

Age:Albian

LOCALITY:SBI03: Northern end of the Maranoa Range,near the head of Stewart Creek, about 5 kmeast of Spreydon Homestead (grid ref.644679)

Lithology:Fine grained silty sandstone

Determinations:Barcoona trigonalis (Moore)Cyrenopsis meeki? (Etheridge Jnr)Tancretella secunda Ludbrook

Age:Albian

LOCALITY:SB I09: Near the headwaters of Paddy Creek,about 3 km south of One Tree Hill (grid ref.671671)

Lithology:Calcareous siltstone

Determinations:Dimitobelus diptychus (McCoy)Barcoona trigonalis (Moore)Camptonectes sp.

Age:Albian

ROMA SHEET AREA (Collector E. N.Milligan)

LOCALITY:SBI08: Middle Creek, where Mount Abun­dance road crosses (grid ref. 140688)

Lithology:Calcareous siltstone

Determinations:?Tatella aptiana Whitehouse

Age:Probably Albian

LOCALITY:SB Ill: Blyth Creek, near where the Carnar­von Highway crosses (grid ref. 173678)

Lithology:Calcareous siltstone

Determinations:Tatella aptiana WhitehouseIndet. pelecypodsworm burrowplant fragments

Age:Probably early Albian

148

from GAB 1942 in the Minmi Member ofthe Mitchell area and from GAB 1134 in theDoncaster Member of the Hughenden areaas Tatella aft. maranoana (Etheridge Jnr).In outline the species resembles 'Gari' ellip­tica, but the umbones are centrally placedand the species is proportionately higherthan 'G' elliptica. Tellina sp. figured byEtheridge Snr (1872, pI. 20, fig. 7) fromMaryborough may be related.

Collection SB 125 contains several speci­mens of the crinoid Isocrinus australis(Moore) and the sponge Purisiphoniaclarkei Bowerbank in positions of growth.Associated with these are the brachiopods'Rhynchonella' rustica Moore (1870, p. 245,pI. 10, figs 7-9) and 'A rgyope' wallumbil­laensis Moore (1870, p. 243, pI. 10, figs3-5). Brachiopods are not common in theAptian sequence and are even rarer in theAlbian.

ALBIAN FOSSILS FROM THE COREENA MEM­BER IN THE SURAT BASIN: 1966

COLLECTIONS

The seven collections reported below pro­vide the first record of Albian macrofossilsin the Surat Basin. Two of the collectionsare from the Roma Sheet area, the remain­der from the Mitchell Sheet area.

MITCHELL SHEET AREA (Collector E. N.MiIligan)

LOCALITY:SBIOO: Near tributary of Emu Creek, about5 km east of Mount Abundance (grid ref.668684)

Lithology:'Belemnite conglomerate' in cross-laminatedglauconitic siltstone

Determinations:Dimitobellls diptychlls (McCoy)Peratobellls sp. noy.Indet. pelecypod

Age:Early Albian

LOCALITY:SB 101: Near tributary of Emu Creek, about3 km east of Mount Abundance (grid ref.667685)

Lithology:Coquina bands in calcareous siltstone

Determinations:AlIcellina hllghendenensis (Etheridge Snr)Barcoona trigonalis (Moore)Maccoyella corbiensis (Moore)Mesosaccella randsi (Etheridge Jnr)

'Yoldia' !reytagi LudbrookElIspira reflecta (Moore)Indet. belemnite

Age:Probably early Albian

LOCALITY:SB 102: East of where road crosses BackCreek, about 6.5 km north of Amby (gridref. 638708)

Lithology:Siltstone

Determinations:Dimitobellls diptychus (McCoy)

Age:Albian

LOCALITY:SBI03: Northern end of the Maranoa Range,near the head of Stewart Creek, about 5 kmeast of Spreydon Homestead (grid ref.644679)

Lithology:Fine grained silty sandstone

Determinations:Barcoona trigonalis (Moore)Cyrenopsis meeki? (Etheridge Jnr)Tancretella secunda Ludbrook

Age:Albian

LOCALITY:SB I09: Near the headwaters of Paddy Creek,about 3 km south of One Tree Hill (grid ref.671671)

Lithology:Calcareous siltstone

Determinations:Dimitobelus diptychus (McCoy)Barcoona trigonalis (Moore)Camptonectes sp.

Age:Albian

ROMA SHEET AREA (Collector E. N.Milligan)

LOCALITY:SBI08: Middle Creek, where Mount Abun­dance road crosses (grid ref. 140688)

Lithology:Calcareous siltstone

Determinations:?Tatella aptiana Whitehouse

Age:Probably Albian

LOCALITY:SB Ill: Blyth Creek, near where the Carnar­yon Highway crosses (grid ref. 173678)

Lithology:Calcareous siltstone

Determinations:Tatella aptiana WhitehouseIndet. pelecypodsworm burrowplant fragments

Age:Probably early Albian

-------------

REMARKS

An Albian age for these collections isindicated by the presence of the belemniteDimitobelus diptychus at SB100, SB 102,and SB 109, and the pelecypod A ucellinahughendenensis at SB 101.

The fauna and its mode of preservationare remarkably similar to those reported byDay (1966b) from the lower part of theCoreena Member in the Augathella andTambo areas. Collection SB 100 is a 'belem­nite conglomerate' composed of large num­bers of Dimitobelus diptychus together withseveral guards of a new species of thetypically Aptian genus Peratobelus.

Identical 'belemnite conglomerates' witha mixture of Aptian and Albian species werereported by Day (1966b, 1967a) fromGAB 1933 in the Tambo area, and fromGAB2039, GAB2057, and GAB2059 in theAugathella area. Coquinas of the small pele­cypod Barcoona trigonalis occur at SB101and SB109. In the Coreena Member theseare strikingly developed, although the spe­cies is known to occur in the DoncasterMember of the Tambo area, and in theMackunda Formation of the Manuka area.Only A ucellina hughendenensis is not knownfrom the Coreena Member in the Augathellaand Tambo areas, but this species is com­mon in outcrops of the Coreena Membernear Barcaldine and Aramac.

The correspondence of faunas is closelyparalleled by lithological and stratigraphicalsimilarities. The silty sediments with thefauna reported herein are very like those ofthe Coreena Member. Further, they occupya similar stratigraphic position immediatelyabove the Aptian Doncaster Member.Clearly, these silty sediments cropping outsouth of Mitchell and Roma are to be cor­related with the Coreena Member of theAugathella and Tambo areas.

Dimitobelus diptychus is abundantly rep­resented at SB 100 by fairly large clavateforms, together with smaller spindle-shapedguards, which in reports on Coreena Mem­ber fossils from the Tambo and Augathellaareas were compared with Dimitobelusliversidgei. The latter may be young indivi­duals of D. diptychus. Several specimens

149

clearly exhibit the double lateral lines anddorsolateral and ventrolateral grooves whichtypify the genus. At SB102 and SBI09, D.diptychus is represented by fewer specimenswhich are less well preserved. Reasons forconsidering D. diptychus an early Albianspecies were elaborated in the reports on theCoreena Member fossils from the Tamboarea (Day, 1966b, 1967a).

There are several guards designated Pera­tobelus sp. novo in the 'belemnite conglomer­ate' at SB I00, but this species is not nearlyas abundant as D. diptychus.

The guards are large and cylindrical andshow the two simple ventrolateral groovescharacteristic of Peratobelus. The alveolusis very deep and is capable of accommo­dating a large phragmocone. Large phrag­mocones were described from the 'PalmerRiver' (Carpentaria Basin) by Tenison­Woods (1883, p. 150, pI. 7, fig. 1) asBelemnites selheimi. However, the writer hasobserved large phragmocones associated withquite small guards in Geological Survey ofQueensland collections from the 'WalshRiver'. Thus the present guards represent adifferent species. As remarked in earlierreports Peratobelus is a typically Aptiangenus and some of its occurrences with theAlbian Dimitobelus may be remanie ones.

Aucellina hughendenensis is representedat SBI0l by a few left and right valves. Theleft valves have the narrow umbones, pos­terior obliquity, and radial ornament charac­teristic of the early to late Albian species.

At SB101 there is a single well-preservedleft valve identified with the Aptian speciesMaccoyella corbiensis. This species wasreported from GAB 1933 in the CoreenaMember of the Tambo area, where it wasregarded as a derived species (Day, 1967b).This explanation may be invoked again here,although like Peratobelus sp. nov., the spe­cies may range into the early Albian.

The single left valve of Camptonectes sp.from SB I09 has strong radial ornament. Theform is conspecific with similarly designatedpectinids from the Coreena Member, AIIaruMudstone, and Mackunda Formation.

An internal mould of a left valve ofTatella from SBlll has the shape of theprobable Albian species Tatella aptiana

-------------

REMARKS

An Albian age for these collections isindicated by the presence of the belemniteDimitobelus diptychus at SB100, SB 102,and SB 109, and the pelecypod A ucellinahughendenensis at SB 101.

The fauna and its mode of preservationare remarkably similar to those reported byDay (1966b) from the lower part of theCoreena Member in the Augathella andTambo areas. Collection SB 100 is a 'belem­nite conglomerate' composed of large num­bers of Dimitobelus diptychus together withseveral guards of a new species of thetypically Aptian genus Peratobelus.

Identical 'belemnite conglomerates' witha mixture of Aptian and Albian species werereported by Day (1966b, 1967a) fromGAB 1933 in the Tambo area, and fromGAB2039, GAB2057, and GAB2059 in theAugathella area. Coquinas of the small pele­cypod Barcoona trigonalis occur at SB101and SB109. In the Coreena Member theseare strikingly developed, although the spe­cies is known to occur in the DoncasterMember of the Tambo area, and in theMackunda Formation of the Manuka area.Only A ucellina hughendenensis is not knownfrom the Coreena Member in the Augathellaand Tambo areas, but this species is com­mon in outcrops of the Coreena Membernear Barcaldine and Aramac.

The correspondence of faunas is closelyparalleled by lithological and stratigraphicalsimilarities. The silty sediments with thefauna reported herein are very like those ofthe Coreena Member. Further, they occupya similar stratigraphic position immediatelyabove the Aptian Doncaster Member.Clearly, these silty sediments cropping outsouth of Mitchell and Roma are to be cor­related with the Coreena Member of theAugathella and Tambo areas.

Dimitobelus diptychus is abundantly rep­resented at SB 100 by fairly large clavateforms, together with smaller spindle-shapedguards, which in reports on Coreena Mem­ber fossils from the Tambo and Augathellaareas were compared with Dimitobelusliversidgei. The latter may be young indivi­duals of D. diptychus. Several specimens

149

clearly exhibit the double lateral lines anddorsolateral and ventrolateral grooves whichtypify the genus. At SB102 and SBI09, D.diptychus is represented by fewer specimenswhich are less well preserved. Reasons forconsidering D. diptychus an early Albianspecies were elaborated in the reports on theCoreena Member fossils from the Tamboarea (Day, 1966b, 1967a).

There are several guards designated Pera­tobelus sp. novo in the 'belemnite conglomer­ate' at SB I00, but this species is not nearlyas abundant as D. diptychus.

The guards are large and cylindrical andshow the two simple ventrolateral groovescharacteristic of Peratobelus. The alveolusis very deep and is capable of accommo­dating a large phragmocone. Large phrag­mocones were described from the 'PalmerRiver' (Carpentaria Basin) by Tenison­Woods (1883, p. 150, pI. 7, fig. 1) asBelemnites selheimi. However, the writer hasobserved large phragmocones associated withquite small guards in Geological Survey ofQueensland collections from the 'WalshRiver'. Thus the present guards represent adifferent species. As remarked in earlierreports Peratobelus is a typically Aptiangenus and some of its occurrences with theAlbian Dimitobelus may be remanie ones.

Aucellina hughendenensis is representedat SBI0l by a few left and right valves. Theleft valves have the narrow umbones, pos­terior obliquity, and radial ornament charac­teristic of the early to late Albian species.

At SB101 there is a single well-preservedleft valve identified with the Aptian speciesMaccoyella corbiensis. This species wasreported from GAB 1933 in the CoreenaMember of the Tambo area, where it wasregarded as a derived species (Day, 1967b).This explanation may be invoked again here,although like Peratobelus sp. nov., the spe­cies may range into the early Albian.

The single left valve of Camptonectes sp.from SB I09 has strong radial ornament. Theform is conspecific with similarly designatedpectinids from the Coreena Member, AIIaruMudstone, and Mackunda Formation.

An internal mould of a left valve ofTatella from SBlll has the shape of theprobable Albian species Tatella aptiana

150

Whitehouse (1925) from the 'Lake EyreBasin'. The specimen from SB 109 is lesscomplete.

Left valves of posteriorly truncate nucu­lanids are referred to two species, Mesosa­cella randsi and 'Yoldia' freytagi. Theseforms have been reported from the CoreenaMember, Allaru Mudstone, and MackundaFormation.

The sole gastropod in these collections isthe naticid Euspira reflecta, which is repre­sented at SB 101 by several small specimens.In the Eromanga Basin this species rangesthrough the entire Aptian-Albian sequence.

In addition collection SB 111 containsnumerous plant fragments and worm bur­rows.

REFERENCES

BRUNNSCHWEILER, R. 0., 1960-Marine fossilsfrom the Upper Jurassic and the LowerCretaceous of Dampier Peninsula, WesternAustralia. Bur. Miner. Resour. Aust. Bull. 59,I-52, pis 1-3.

CASEY. R., 196O-A monograph of the Ammono­idea of the Lower Greensand. Palaeontogr.Soc. Monogr.• Pt I, i-xxxvi, 1-44, pis 1-10.

Cox. L. R., 1961-The molluscan fauna and pro­bable Lower Cretaceous age of the NanutarraFormation of Western Australia. Bur. Miner.Resour. Aust. Bull. 61, I-51, pis 1-7.

DAY. R. W., 1964a-Stratigraphy of the Roma­Wallumbilla area. Geo!' Surv. Qld Pub!. 318,1-23.

DAY, R. W., 1964b-Appendix D in VINE, R. R.,CASEY. D. J., and JOHNSON, N. E. A.,-Pro­gress report, 1963, on the geology of part ofthe northeastern Eromanga Basin. Bur. Miner.Resour. Aust. Rec. 1964/39 (unpubl.).

DAY. R. W., 1966a-Aptian macrofossils from thenorthern half of the MitchelI 1:250000 SheetArea; Appendix 2 in EXON, N. F., CASEY.D. J., and GALLOWAY. M. C.: The geology ofthe northern half of the Mitchell 1:250000Sheet area, Queensland. Ibid.. 1966/90 (un­publ.).

DAY. R. W., 1966b-Lower Cretaceous macro­fossils from the Tambo and Augathella1:250000 Sheet areas; Appendix I in EXON.N. F. GALLOWAY, M. c., CASEY, D. J., andKIRKEGAARD, A. G.: The geology of theTambo, Augathella and Blackall 1:250 000Sheet areas, Queensland. Ibid., 1966/89 (un­publ.).

DAY, R. W., 1967a-A mixed Roma-Tambo faunafrom the Tambo area. Qld Govt Min. J.• 68,10-12.

DAY, R. W., 1967b-Marine Lower Cretaceousfossils from the Minmi Member, BlythesdaleFormation, Roma-Wallumbilla area. Geol.Surv. Qld Publ, 335, palaeont. Pap. 9. 1-30,pIs 1-6.

DAY, R. W., 1969-The Lower Cretaceous of theGreat Artesian Basin; in Campbell, K. S. W.(Ed.): Stratigraphy and Palaeontology.Essays in Honour of Dorothy Hill. Canberra,ANU Press, 140-73.

DAY, R. W., 1974-Aptian ammonites from theEromanga and Surat Basins, Queensland.Geol. Surv. Qld Pub!. 360, palaeont. Pap. 34,1-9, pIs 1-8.

ETHERIDGE, R. Snr, 1872-Descriptions of thePalaeozoic and Mesozoic fossils of Queens­land; Appendix I in DAINTREE, R.: Notes onthe geology of the colony of Queensland.Quart. J. geol. Soc. Lond., 28, 317-50.

ETHERIDGE, R. Jnr, 1892-ln JACK, R. L., andETHERIDGE, R. Jnr: The geology and palaeon­tology of Queensland and New Guinea. Geo!'Surv. Qld Pub!. 92, 2 vols.

ETHERIlXiE, R. Jnr, 1901-Additional notes on thepalaeontology of Queensland (Pt 2). Ibid.,158, 5-37.

ETHERIlXiE, R. Jnr, 1902-The Cretaceous mol­lusca of South Australia and the NorthernTerritory. Mem. Roy. Soc. S. Aust., 2(1),1-54, pIs 1-7.

ETHERIDGE, R. Jnr, 1909-Lower Cretaceous fos­sils from the sources of the Barcoo, Wardand Nive Rivers, south central Queensland.Pt 2-Cephalopoda. Rec. Aust. Mus., 7, 135­65, 235-40, pIs 30-49, 65-68.

HUDLESTON, W. H., 1890-Further notes on somemollusca from South Australia. Geo!' Mag.,7(N.S.), 241-6, pI. 9.

LUDBRooK, Nelly H., 1966-Cretaceous biostrati­graphy of the Great Artesian Basin in SouthAustralia. Geo!' Surv. S. Aust. Bull. 40, 1-223,pIs 1-28.

MooRE. c., 1870-Australian Mesozoic geologyand palaeontology. Quart. J. geo!. Soc. Lond.,26, 226-61, pis 10-18.

SPITZ, A., 1914-A Lower Cretaceous fauna fromthe Himalayan Guiemal Sandstone togetherwith descriptions of a few fossils from theChikkim Series. Rec. Geol. Surv. India., 44,197-224.

TENISON-WooDS, 1. E., 1883-0n some Mesozoicfossils from the Palmer River, Queensland.J. Proc. Roy. Soc. N.S.W., 16, 147-54, pIs 7,8, 10.

WHITEHOUSE, F. W., 1925-0n RolIing Downsfossils collected by Prof. J. W. Gregory.Trans. Roy. Soc. S. Aust., 49, 27-36.

WHITEHOUSE, F. W., 1946-A marine early Creta­caceous fauna from Stanwell (Rockhamptondistrict). Proc. Roy. Soc. Qld., 57, 7-20, pI. 1.

WOODS, J. T., 1962-A new species of Hatcheri­ceras (Ammonoidea) from north Queensland.J. geol. Soc. Aust., 8, 239-43, pI. 1.

WOODS, J. T., 1963-Marine Cretaceous fossilsfrom the Cape Melville 4-mile sheet area.Rep. Geol. Surv. Qld (unpubl.).

150

Whitehouse (1925) from the 'Lake EyreBasin'. The specimen from SB 109 is lesscomplete.

Left valves of posteriorly truncate nucu­lanids are referred to two species, Mesosa­cella randsi and 'Yoldia' freytagi. Theseforms have been reported from the CoreenaMember, Allaru Mudstone, and MackundaFormation.

The sole gastropod in these collections isthe naticid Euspira reflecta, which is repre­sented at SB 101 by several small specimens.In the Eromanga Basin this species rangesthrough the entire Aptian-Albian sequence.

In addition collection SB 111 containsnumerous plant fragments and worm bur­rows.

REFERENCES

BRUNNSCHWEILER, R. 0., 1960-Marine fossilsfrom the Upper Jurassic and the LowerCretaceous of Dampier Peninsula, WesternAustralia. Bur. Miner. Resour. Aust. Bull. 59,I-52, pis 1-3.

CASEY. R., 196O-A monograph of the Ammono­idea of the Lower Greensand. Palaeontogr.Soc. Monogr.• Pt I, i-xxxvi, 1-44, pis 1-10.

Cox. L. R., 1961-The molluscan fauna and pro­bable Lower Cretaceous age of the NanutarraFormation of Western Australia. Bur. Miner.Resour. Aust. Bull. 61, I-51, pis 1-7.

DAY. R. W., 1964a-Stratigraphy of the Roma­Wallumbilla area. Geo/. Surv. Qld Publ. 318,1-23.

DAY, R. W., 1964b-Appendix D in VINE, R. R.,CASEY. D. J., and JOHNSON, N. E. A.,-Pro­gress report, 1963, on the geology of part ofthe northeastern Eromanga Basin. Bur. Miner.Resour. Aust. Rec. 1964/39 (unpubl.).

DAY. R. W., 1966a-Aptian macrofossils from thenorthern half of the MitchelI 1:250000 SheetArea; Appendix 2 in EXON, N. F., CASEY.D. J., and GALLOWAY. M. C.: The geology ofthe northern half of the Mitchell 1:250000Sheet area, Queensland. Ibid.. 1966/90 (un­publ.).

DAY. R. W., 1966b-Lower Cretaceous macro­fossils from the Tambo and Augathella1:250000 Sheet areas; Appendix I in EXON.N. F. GALLOWAY, M. c., CASEY, D. J., andKIRKEGAARD, A. G.: The geology of theTambo, Augathella and Blackall 1:250 000Sheet areas, Queensland. Ibid., 1966/89 (un­publ.).

DAY, R. W., 1967a-A mixed Roma-Tambo faunafrom the Tambo area. Qld Govt Min. J.• 68,10-12.

DAY, R. W., 1967b-Marine Lower Cretaceousfossils from the Minmi Member, BlythesdaleFormation, Roma-Wallumbilla area. Geol.Surv. Qld Publ, 335, palaeont. Pap. 9. 1-30,pIs 1-6.

DAY, R. W., 1969-The Lower Cretaceous of theGreat Artesian Basin; in Campbell, K. S. W.(Ed.): Stratigraphy and Palaeontology.Essays in Honour of Dorothy Hill. Canberra,ANU Press, 140-73.

DAY, R. W., 1974-Aptian ammonites from theEromanga and Surat Basins, Queensland.Geol. Surv. Qld Pub/. 360, palaeont. Pap. 34,1-9, pIs 1-8.

ETHERIDGE, R. Snr, 1872-Descriptions of thePalaeozoic and Mesozoic fossils of Queens­land; Appendix I in DAINTREE, R.: Notes onthe geology of the colony of Queensland.Quart. J. geol. Soc. Lond., 28, 317-50.

ETHERIDGE, R. Jnr, 1892-ln JACK, R. L., andETHERIDGE, R. Jnr: The geology and palaeon­tology of Queensland and New Guinea. Geol.Surv. Qld Publ. 92, 2 vols.

ETHERIlXiE, R. Jnr, 1901-Additional notes on thepalaeontology of Queensland (Pt 2). Ibid.,158, 5-37.

ETHERIlXiE, R. Jnr, 1902-The Cretaceous mol­lusca of South Australia and the NorthernTerritory. Mem. Roy. Soc. S. Aust., 2(1),1-54, pIs 1-7.

ETHERIDGE, R. Jnr, 1909-Lower Cretaceous fos­sils from the sources of the Barcoo, Wardand Nive Rivers, south central Queensland.Pt 2-Cephalopoda. Rec. Aust. Mus., 7, 135­65, 235-40, pIs 30-49, 65-68.

HUDLESTON, W. H., 1890-Further notes on somemollusca from South Australia. Geol. Mag.,7(N.S.), 241-6, pI. 9.

LUDBRooK, Nelly H., 1966-Cretaceous biostrati­graphy of the Great Artesian Basin in SouthAustralia. Geol. Surv. S. Aust. Bull. 40, 1-223,pIs 1-28.

MooRE. c., 1870-Australian Mesozoic geologyand palaeontology. Quart. J. geol. Soc. Lond.,26, 226-61, pis 10-18.

SPITZ, A., 1914-A Lower Cretaceous fauna fromthe Himalayan Guiemal Sandstone togetherwith descriptions of a few fossils from theChikkim Series. Rec. Geol. Surv. India., 44,197-224.

TENISON-WooDS, 1. E., 1883-0n some Mesozoicfossils from the Palmer River, Queensland.J. Proc. Roy. Soc. N.S.W., 16, 147-54, pIs 7,8, 10.

WHITEHOUSE, F. W., 1925-0n RolIing Downsfossils collected by Prof. J. W. Gregory.Trans. Roy. Soc. S. Aust., 49, 27-36.

WHITEHOUSE, F. W., 1946-A marine early Creta­caceous fauna from Stanwell (Rockhamptondistrict). Proc. Roy. Soc. Qld., 57, 7-20, pI. 1.

WOODS, J. T., 1962-A new species of Hatcheri­ceras (Ammonoidea) from north Queensland.J. geol. Soc. Aust., 8, 239-43, pI. 1.

WOODS, J. T., 1963-Marine Cretaceous fossilsfrom the Cape Melville 4-mile sheet area.Rep. Geol. Surv. Qld (unpubl.).

151

APPENDIX 2NOTES ON THE VERTEBRATE FAUNA OF THE CHINCHILLA SAND*

byA. BARTHOLOMAI (Queensland Museum) and J. T. WOODS (Geological Survey

of Queensland)

The name Chinchilla Sand was proposedby Woods (1960) for a predominantlysandy sequence of fluviatile sediments ex­posed mainly in the valley of the CondamineRiver for a distance of 65 km between Nan­gram Lagoon in the west and Warra in theeast. Previously Woods (1956) had used thename Chinchilla Formation for representa­tives of this sequence near Chinchilla.

The Chinchilla Conglomerate of Etheridge(1892) is a part of the formation, and thinbeds of well lithified calcareous sandstonegrading into grit and conglomerate are pro­minent in outcrop, including the type sectionalong the north bank of the CondamineRiver near the Chinchilla Rifle Range. Themain sediment is weakly consolidated greyto yellowish and light brown sand, whichgrades into grit and sandy clay. The pres­ence of quartzitic material, including silcreteand ferruginous sandstone, in the coarserclastics suggests that they were derived fromthe Orallo Formation and its lateritized pro­files. In places low down in the streams theChinchilla Sand can be seen to rest oneroded mottled surfaces of these Mesozoicrocks.

In the west the Chinchilla Sand appearsas outliers, but to the east it crops out ininliers before disappearing below the darkalluvial clays of Quaternary age. OtherQuaternary alluvia show a valley-in-valleyrelation with the Chnchilla Sand in thevicinity of the type section, and it appearsthat there is a small angular unconformitybetween the Chinchilla Sand and the Quater­nary alluvia, and that the regional dip of theformation is less than, or the reverse of, thepresent stream gradient.

The northern boundary of the sequenceis difficult to map because of the lack ofexposures and the similarity of the pedo­calcic clay soils developed both on the

Injune Creek Beds and many parts of theChinchilla Sand. The homogeneous orange­red sands so conspicuous in the town ofChinchilla are not part of the ChinchillaSand, and apparently represent a youngerterrace deposit along Charleys Creek.

The measured thickness in the type areais 20 m, while at least 32 ill is present inBrowns Bore at Brigalow (on the evidenceof samples preserved by the Geological Sur­vey of Queensland).

Vertebrate fossils and, in particular, rep­tilian remains, are common in the ChinchillaSand. They include teeth and dermal scutesof the large crocodile Pallimnarchus pollens,carapace fragments of the freshwater tor­toises Chelodina insculpta, Chelymys arata,C. uberima, C. antiqua, Pelocomastes ampla,and Trionyx australiensis, and teeth and ver­tebrae of the large goanna Varanus dirus.Fish remains include buccal plates of thelungfish Epiceratodus forsteri, while thelarge bird fauna includes fragmentaryremains of Anas elapsa, Biziura exhumata,Chosornis praeteritus, Dendrocygna valdi­pinnis, Fulica prior, Gallinula strenuipes,Nyroca reclusa, N. robusta, Plotus pan'us,Porphyrio? reperta, X enorhynchus nanus,Necraster alacer, Dromaius gracilis, D. patri­cius, and Platalea subtenuis.

The predominant marsupial is the dipro­todontid Euryzygoma dunense, which issufficiently abundant to be useful as a guidefossil for the sequence. Other diprotodontidsinclude Euowenia grata and Palorchestesparvus. Dasyurids are represented by Sarco­philus prior and Thylacinus rostralis, whilethe phalangerids include Pseudochirus? nota­bilis and the 'marsupial lion' Thylacoleocrassidentatus. Macropodids are moderatelyabundant, the most common being Sthenurusantiquus, S. notabilis, Troposodon minor,Macropus pan, Protemnodon anak, and'Halmaturus' indra.

* This Appendix was written for BMR Record 1968/53 in 1968 and has not been fully up-dated.

151

APPENDIX 2NOTES ON THE VERTEBRATE FAUNA OF THE CHINCHILLA SAND*

byA. BARTHOLOMAI (Queensland Museum) and J. T. WOODS (Geological Survey

of Queensland)

The name Chinchilla Sand was proposedby Woods (1960) for a predominantlysandy sequence of fluviatile sediments ex­posed mainly in the valley of the CondamineRiver for a distance of 65 km between Nan­gram Lagoon in the west and Warra in theeast. Previously Woods (1956) had used thename Chinchilla Formation for representa­tives of this sequence near Chinchilla.

The Chinchilla Conglomerate of Etheridge(1892) is a part of the formation, and thinbeds of well lithified calcareous sandstonegrading into grit and conglomerate are pro­minent in outcrop, including the type sectionalong the north bank of the CondamineRiver near the Chinchilla Rifle Range. Themain sediment is weakly consolidated greyto yellowish and light brown sand, whichgrades into grit and sandy clay. The pres­ence of quartzitic material, including silcreteand ferruginous sandstone, in the coarserclastics suggests that they were derived fromthe Orallo Formation and its lateritized pro­files. In places low down in the streams theChinchilla Sand can be seen to rest oneroded mottled surfaces of these Mesozoicrocks.

In the west the Chinchilla Sand appearsas outliers, but to the east it crops out ininliers before disappearing below the darkalluvial clays of Quaternary age. OtherQuaternary alluvia show a valley-in-valleyrelation with the Chnchilla Sand in thevicinity of the type section, and it appearsthat there is a small angular unconformitybetween the Chinchilla Sand and the Quater­nary alluvia, and that the regional dip of theformation is less than, or the reverse of, thepresent stream gradient.

The northern boundary of the sequenceis difficult to map because of the lack ofexposures and the similarity of the pedo­calcic clay soils developed both on the

Injune Creek Beds and many parts of theChinchilla Sand. The homogeneous orange­red sands so conspicuous in the town ofChinchilla are not part of the ChinchillaSand, and apparently represent a youngerterrace deposit along Charleys Creek.

The measured thickness in the type areais 20 m, while at least 32 ill is present inBrowns Bore at Brigalow (on the evidenceof samples preserved by the Geological Sur­vey of Queensland).

Vertebrate fossils and, in particular, rep­tilian remains, are common in the ChinchillaSand. They include teeth and dermal scutesof the large crocodile Pallimnarchus pollens,carapace fragments of the freshwater tor­toises Chelodina insculpta, Chelymys arata,C. uberima, C. antiqua, Pelocomastes ampla,and Trionyx australiensis, and teeth and ver­tebrae of the large goanna Varanus dirus.Fish remains include buccal plates of thelungfish Epiceratodus forsteri, while thelarge bird fauna includes fragmentaryremains of Anas elapsa, Biziura exhumata,Chosornis praeteritus, Dendrocygna valdi­pinnis, Fulica prior, Gallinula strenuipes,Nyroca reclusa, N. robusta, Plotus pan'us,Porphyrio? reperta, X enorhynchus nanus,Necraster alacer, Dromaius gracilis, D. patri­cius, and Platalea subtenuis.

The predominant marsupial is the dipro­todontid Euryzygoma dunense, which issufficiently abundant to be useful as a guidefossil for the sequence. Other diprotodontidsinclude Euowenia grata and Palorchestesparvus. Dasyurids are represented by Sarco­philus prior and Thylacinus rostralis, whilethe phalangerids include Pseudochirus? nota­bilis and the 'marsupial lion' Thylacoleocrassidentatus. Macropodids are moderatelyabundant, the most common being Sthenurusantiquus, S. notabilis, Troposodon minor,Macropus pan, Protemnodon anak, and'Halmaturus' indra.

* This Appendix was written for BMR Record 1968/53 in 1968 and has not been fully up-dated.

152

A tentative Pliocene age was assigned tothe Chinchilla Sand by Woods (1960),mainly on the faunal evidence. In 1920Sahni assigned a Tertiary age to three speci­mens of fossil wood from the CondamineRiver, near Fairymeadow, southwest ofChinchilla: they were the conifers Mesem­brioxylon {luviale and M. fusiforme and anindeterminable dicotyledon.

Recently, evidence of superposition of thePleistocene alluvia, characterized by theDiprotodon optatus fauna, on the ChinchillaSand in its subsurface extent has becomeavailable at Dalby. A tooth of Euryzygomadunense was recovered from sand at adepth of 26.5 to 27.4 m in the Dalby TownBore, adjacent to the existing ProductionBore No. 2, por. 16, Par. St Ruth.

REFERENCES

ETHERIDGE, R., Jnr-in JACK, R. L., & ErnERIDGE,R. Jnr, 1892: The geology and palaeontologyof Queensland and New Guinea. Geol. Surv.Qld Publ. 92, 2 vols.

WOODS, J. T., 1956-The skull of Thylaeoleoearnifex. Mem. Qld Mus. 13, 177-93.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave deposits; in Hill & Denmead (Eds):The geology of Queensland. J. geol. Soc.Aust., 7, 393-403.

SAHNI, R, 192O-Petrified plant remains from theQueensland Mesozoic and Tertiary forma­tions. Geol. Surv. Qld Publ. 267, 1-49.

152

A tentative Pliocene age was assigned tothe Chinchilla Sand by Woods (1960),mainly on the faunal evidence. In 1920Sahni assigned a Tertiary age to three speci­mens of fossil wood from the CondamineRiver, near Fairymeadow, southwest ofChinchilla: they were the conifers Mesem­brioxylon [luviale and M. fusiforme and anindeterminable dicotyledon.

Recently, evidence of superposition of thePleistocene alluvia, characterized by theDiprotodon optatus fauna, on the ChinchillaSand in its subsurface extent has becomeavailable at Dalby. A tooth of Euryzygomadunense was recovered from sand at adepth of 26.5 to 27.4 m in the Dalby TownBore, adjacent to the existing ProductionBore No. 2, por. 16, Par. St Ruth.

REFERENCES

ETHERIDGE, R., Jnr-in JACK, R. L., & ErnERIDGE,R. Jnr, 1892: The geology and palaeontologyof Queensland and New Guinea. Geol. Surv.Qld Publ. 92, 2 vols.

WOODS, J. T., 1956-The skull of Thylaeoleoearnifex. Mem. Qld Mus. 13, 177-93.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave deposits; in Hill & Denmead (Eds):The geology of Queensland. J. geol. Soc.Aust., 7, 393-403.

SAHNI, R, 192O-Petrified plant remains from theQueensland Mesozoic and Tertiary forma­tions. Geol. Surv. Qld Publ. 267, 1-49.

153

APPENDIX 3NOTES ON THE FOSSILIFEROUS PLEISTOCENE FLUVIATILE DEPOSITS

OF THE EASTERN DARLING DOWNS

byA. BARTHOLOMAI*

(Queensland Museum)

Widespread f1uviatile deposits contamtngabundant remains of Pleistocene vertebratesoccur in the eastern Darling Downs. Thedeposits lie to the east of Warra and areexposed mainly in the banks of the Con­damine River and its tributaries. The pres­ence of vertebrate remains has been knownsince the first settlement in the 1840s.

Leichhardt (1847), Stutchbury (1853,1854), Bennett ( 1872), and Gregory(1879) made notes on the geology of thedeposits. A full discussion, together withdescribed sections for King Creek and theCondamine River, is presented in Woods(1960). Most of the fossil vertebrates re­covered have come from poorly consolidatedblack and dark red-brown calcareous claysoils, but some come from coarse ferrugin­ous quartzose sands in the Dalby-Macalisterarea. The Pleistocene sediments were formedas a result of dissection of the widespreadweathered sediments of the pre-Miocene sur­face, and the basalts of the Great Divide.The Main Range, the Bunya Mountains, andattendant spurs and mesas represent theremnants of this major source. The sandsappear to have been derived from Mesozoicrocks.

Recent black surface soil, which does notappear to be much more than a metre deep,is widespread, and outcrops of the under­lying Pleistocene sediments are restricted tosporadic exposures in creeks and wells. Thedeposits generally stand at a higher topo­graphic level than the recent drainage sys­tem, but it is difficult to establish the detailedstratigraphy because of the lenticularity ofthe beds, the rapid lateral variations in litho­logy, and the discontinuity of outcrops.

Water-bores and wells have providedsome information on the distribution of thePleistocene sediments away from the river

sections. Bennett (1872) recorded a fossilkangaroo at a depth of 42 m at JimbourPlains, and Pleistocene species have beenrecorded from nearby surface exposuresalong Jimbour Creek. These facts give anindication of the possible minimum thicknessof Upper Cainozoic sediments in that area.Woods (1960) estimatcd that the thicknessof alluvium in the Dalby section of the Con­damine River ranges up to 49 m, althoughthe sequence may include some Pliocenesediments.

The Pleistocene f1uviatile deposits havebeen referred to as 'Older Alluvial or FossilDrift' by Gregory (1879), and Etheridge(Jack & Etheridge, 1892) applied the term'Fluviatile Deposits' to them. In the samepublication, Jack listed 'High-Level Riverand Lake Drifts' and 'Bone Drifts' in hispost-Pliocene deposits. The name 'Dipro­todon Beds' was proposed by Bryan (1928)for these fossiliferous alluvia. Macintosh( 1967) informally introduced several strati­graphic names for soil units in the Daly­rymple/King Creek area to the southwest,but recent CSIRO Soils Division coresretrieved from that area suggest a more com­plex stratigraphic relation than envisaged inthat paper.

Bartholomai & Woods (Appendix 2) haveshown that the Pleistocene alluvia are super­imposed on the Pliocene? Chinchilla Sandat Dalby at a depth of 26.5 to 27.4 m.

Among the fossil vertebrates recorded inthe Pleistocene fluviatile deposits, marsupialspredominate, but birds, reptiles, and fish arealso present. The monotreme Ornithorhyn­chlls agilis is rare. The large marsupial Dip­rotodon optatlls dominates the fauna, butother diprotodontids, including D. minor,Nototheriwn inerme, Zygomatllrlls triloblls,and Palorchestes azael, are also widely dis-

* This Appendix was written for BMR Record 1972/53 in 1969, and has not been fully up-dated.

153

APPENDIX 3NOTES ON THE FOSSILIFEROUS PLEISTOCENE FLUVIATILE DEPOSITS

OF THE EASTERN DARLING DOWNS

byA. BARTHOLOMAI*

(Queensland Museum)

Widespread f1uviatile deposits contamtngabundant remains of Pleistocene vertebratesoccur in the eastern Darling Downs. Thedeposits lie to the east of Warra and areexposed mainly in the banks of the Con­damine River and its tributaries. The pres­ence of vertebrate remains has been knownsince the first settlement in the 1840s.

Leichhardt (1847), Stutchbury (1853,1854), Bennett ( 1872), and Gregory(1879) made notes on the geology of thedeposits. A full discussion, together withdescribed sections for King Creek and theCondamine River, is presented in Woods(1960). Most of the fossil vertebrates re­covered have come from poorly consolidatedblack and dark red-brown calcareous claysoils, but some come from coarse ferrugin­ous quartzose sands in the Dalby-Macalisterarea. The Pleistocene sediments were formedas a result of dissection of the widespreadweathered sediments of the pre-Miocene sur­face, and the basalts of the Great Divide.The Main Range, the Bunya Mountains, andattendant spurs and mesas represent theremnants of this major source. The sandsappear to have been derived from Mesozoicrocks.

Recent black surface soil, which does notappear to be much more than a metre deep,is widespread, and outcrops of the under­lying Pleistocene sediments are restricted tosporadic exposures in creeks and wells. Thedeposits generally stand at a higher topo­graphic level than the recent drainage sys­tem, but it is difficult to establish the detailedstratigraphy because of the lenticularity ofthe beds, the rapid lateral variations in litho­logy, and the discontinuity of outcrops.

Water-bores and wells have providedsome information on the distribution of thePleistocene sediments away from the river

sections. Bennett (1872) recorded a fossilkangaroo at a depth of 42 m at JimbourPlains, and Pleistocene species have beenrecorded from nearby surface exposuresalong Jimbour Creek. These facts give anindication of the possible minimum thicknessof Upper Cainozoic sediments in that area.Woods (1960) estimatcd that the thicknessof alluvium in the Dalby section of the Con­damine River ranges up to 49 m, althoughthe sequence may include some Pliocenesediments.

The Pleistocene f1uviatile deposits havebeen referred to as 'Older Alluvial or FossilDrift' by Gregory (1879), and Etheridge(Jack & Etheridge, 1892) applied the term'Fluviatile Deposits' to them. In the samepublication, Jack listed 'High-Level Riverand Lake Drifts' and 'Bone Drifts' in hispost-Pliocene deposits. The name 'Dipro­todon Beds' was proposed by Bryan (1928)for these fossiliferous alluvia. Macintosh( 1967) informally introduced several strati­graphic names for soil units in the Daly­rymple/King Creek area to the southwest,but recent CSIRO Soils Division coresretrieved from that area suggest a more com­plex stratigraphic relation than envisaged inthat paper.

Bartholomai & Woods (Appendix 2) haveshown that the Pleistocene alluvia are super­imposed on the Pliocene? Chinchilla Sandat Dalby at a depth of 26.5 to 27.4 m.

Among the fossil vertebrates recorded inthe Pleistocene fluviatile deposits, marsupialspredominate, but birds, reptiles, and fish arealso present. The monotreme Ornithorhyn­chlls agilis is rare. The large marsupial Dip­rotodon optatlls dominates the fauna, butother diprotodontids, including D. minor,Nototheriwn inerme, Zygomatllrlls triloblls,and Palorchestes azael, are also widely dis-

* This Appendix was written for BMR Record 1972/53 in 1969, and has not been fully up-dated.

154

tributed. Dasyurids are represented by Thy­lacinus cynocephalus, Sarcophilus laniarius,and Dasyurus sp., and phalangerids includethe 'marsupial lion' Thylacoleo carnifex.Smaller marsupials, including peramelids,are poorly represented. The Macropodidaeis numerically the best represented family,with grazing forms more frequently encoun­tered than browsing types. Propleopus oscil­lans is recorded, but is rare. Macropus titanis particularly abundant, and other kanga­roos such as M. ferragus and M. altus arealso present. Extinct protemnodonts consti­tute a large proportion of the fossil sampleand include Protemnodon anak, P. brehus,and P. raechus. Troposodon minor is alsomoderately well represented, but potoroines,including Aepyprymnus, are less common.Wallabies such as 'Halmaturus' siva, 'H.'thor, and 'H.' indra are occasionally en­countered, as are the more specialized mac-

ropodids Sthenurus andersoni, S. oreas, S.pales, S. tindalei, Procoptodon goliaJz, P.rapha, and P. pusio. Vombatids present in­clude Phascolonus gigas, Phascolomysaugustidens, P. magnus, P. medius, P. mit­oheW, and Lasiorhinus latifrons.

Among the reptilian fossils are the largehorned tortoise Meiolania oweni and thegigantic goanna Megalania prisca. Croco­dilian and tortoise remains are rare.

A large bird fauna includes Tophaetusbrachialis, Pelecanus proavus, Lobivanellussp., Progura gaWnacea, Gallinula peralata,G. strenuipes, Lithophaps ulnaris, Metap­teryx bifrons, Platalea subtenuis, Dromaiuspatricius, Palaeopelargus nobilis, Nacrasteralacer, and Tribonyx effiuxus. The supposedQueensland Moa, Dinornis queenslandiae,has been shown by Scarlett (1969) to havebeen derived from a New Zealand Maorimidden site.

REFERENCES

BENNETI, G., 1872-A trip to Queensland insearch of fossils. Ann. Mag. nat. Hisl., Ser.4, 9, 314-21.

BRYAN, W. H., 1928-A glossary of Queenslandstratigraphy. Spec. Publ. Dep. Geol. Univ.Qld, 1-69.

GREGORY, A. C., 1879-0n the geological featuresof the south-eastern district of Queensland.V. & P. legisl. Assem. Qld, 1879(2), 365-74.

JACK, R. L., & ETHERIDGE, R. Jnr, 1892-Thegeology and palaeontology of Queensland andNew Guinea. Geol. Surv. Qld Publ. 92.

l.EICHHARDT, L., 1847-JOURNAL OF AN OVERLANDEXPEDITION IN AUSTRALIA. London, Boone.

MACINTOSH, N. W. G., 1967-Fossil man inAustralia. Aust. I. Sci., 30, 86-98.

SCARLETI, R., 1969-0n the alleged QueenslandMoa, Dinornis queenslandiae De Vis. Mem.Qld Mus., 15(3), 207-12.

STUTCHBURY, S., 1853-Eleventh tri-monthly re­port upon the geological and mineralogicalstructure of New South Wales. Sydney, Legisl.Coun. Pap., 1853.

STUTCHBURY, S., 1854--Twelfth tri-monthly reportupon the geological and mineralogical struc­ture of New South Wales. Ibid., 1854.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave depostis. I. geol. Soc. Aust.. 7, 393-403.

154

tributed. Dasyurids are represented by Thy­lacinus cynocephalus, Sarcophilus laniarius,and Dasyurus sp., and phalangerids includethe 'marsupial lion' Thylacoleo carnifex.Smaller marsupials, including peramelids,are poorly represented. The Macropodidaeis numerically the best represented family,with grazing forms more frequently encoun­tered than browsing types. Propleopus oscil­lans is recorded, but is rare. Macropus titanis particularly abundant, and other kanga­roos such as M. ferragus and M. altus arealso present. Extinct protemnodonts consti­tute a large proportion of the fossil sampleand include Protemnodon anak, P. brehus,and P. raechus. Troposodon minor is alsomoderately well represented, but potoroines,including Aepyprymnus, are less common.Wallabies such as 'Halmaturus' siva, 'H.'thor, and 'H.' indra are occasionally en­countered, as are the more specialized mac-

ropodids Sthenurus andersoni, S. oreas, S.pales, S. tindalei, Procoptodon goliaJz, P.rapha, and P. pusio. Vombatids present in­clude Phascolonus gigas, Phascolomysaugustidens, P. magnus, P. medius, P. mit­oheW, and Lasiorhinus latifrons.

Among the reptilian fossils are the largehorned tortoise Meiolania oweni and thegigantic goanna Megalania prisca. Croco­dilian and tortoise remains are rare.

A large bird fauna includes Tophaetusbrachialis, Pelecanus proavus, Lobivanellussp., Progura gaWnacea, Gallinula peralata,G. strenuipes, Lithophaps ulnaris, Metap­teryx bifrons, Platalea subtenuis, Dromaiuspatricius, Palaeopelargus nobilis, Nacrasteralacer, and Tribonyx effiuxus. The supposedQueensland Moa, Dinornis queenslandiae,has been shown by Scarlett (1969) to havebeen derived from a New Zealand Maorimidden site.

REFERENCES

BENNETI, G., 1872-A trip to Queensland insearch of fossils. Ann. Mag. nat. Hisl., Ser.4, 9, 314-21.

BRYAN, W. H., 1928-A glossary of Queenslandstratigraphy. Spec. Publ. Dep. Geol. Univ.Qld, 1-69.

GREGORY, A. C., 1879-0n the geological featuresof the south-eastern district of Queensland.V. & P. legisl. Assem. Qld, 1879(2), 365-74.

JACK, R. L., & ETHERIDGE, R. Jnr, 1892-Thegeology and palaeontology of Queensland andNew Guinea. Geol. Surv. Qld Publ. 92.

l.EICHHARDT, L., 1847-JOURNAL OF AN OVERLANDEXPEDITION IN AUSTRALIA. London, Boone.

MACINTOSH, N. W. G., 1967-Fossil man inAustralia. Aust. I. Sci., 30, 86-98.

SCARLETI, R., 1969-0n the alleged QueenslandMoa, Dinornis queenslandiae De Vis. Mem.Qld Mus., 15(3), 207-12.

STUTCHBURY, S., 1853-Eleventh tri-monthly re­port upon the geological and mineralogicalstructure of New South Wales. Sydney, Legisl.Coun. Pap., 1853.

STUTCHBURY, S., 1854--Twelfth tri-monthly reportupon the geological and mineralogical struc­ture of New South Wales. Ibid., 1854.

WOODS, J. T., 1960-Fossiliferous fluviatile andcave depostis. I. geol. Soc. Aust.. 7, 393-403.

155

APPENDIX 4CLAY MINERALS IN THE MID-JURASSIC TO LOWER CRETACEOUS

SEQUENCE

byN. F. ExoN

In mid- I972 18 core samples from BMRstratigraphic holes in the Surat Basin weresubmitted to the Australian Mineral Deve­lopment Laboratories (AMDEL) for semi­quantitative clay analysis. Standard AMDELmethods were used and a report on themethods and results was prepared by Brown( 1972). R. R. Vine in a BMR file note hadpointed out in 1969 that within the Ero­manga Basin 'individual members and for­mations have consistent distinguishing fea­tures in their clay mineralogy, even thoughabsolute differences are small'. The presentlyreported work was designed to see whattrends might emerge from clay mineral ana­lysis within the Surat Basin. The location ofthe holes is shown in the accompanying map(Fig. A) and their stratigraphy is discussedby Exon et al. (1967) and Exon (1972).The positions of the samples in each hole aregiven in Table A.

The sequences involved, from oldest toyoungest, are the fluvial Springbok Sand­stone, the lacustrine Westbourne Formation,the fluvial Gubberamunda Sandstone, thelacustrine Orallo Formation (all Jurassic),and the fluvial Mooga Sandstone and theparalic Coreena Member (both Early Cre­taceous). The Gubberamunda and MoogaSandstones are important aquifers.

The results are summarized in Table Aand Figures Band C and the main resultscan be outlined as follows:

(a) The assemblages are dominated bymontmoriIIonite or kaolinite, the pro­portions of which show a reciprocalrelation (Fig. B).

(b) The proportions of chlorite and ilIiteare directly related to the proportion ofkaolinite (Fig. B).

(c) MontmoriIIonite is predominant in mostof the samples. Only in the two porousaquifer sequences (the lower part ofthe Mooga Sandstone, and the Gub-

beramunda Sandstone) is kaolinite pre­dominant (Fig. B).

(d) The clay mineral assemblages do notshow any obvious relation to the grain­size of the sediment (Fig. B).

(e) Quartz and feldspar trends run parallel(Fig. C).

(f) Siderite is common in the CoreenaMember, Westbourne Formation, andin the Mooga and Springbok Sand­stones (Fig. C).

(g) Glauconite was nowhere identified,although round green grains of glau­conie were very abundant in sample 12.

DiscussionThe clay mineralogy distinguishes the two

aquifer sequences (the Gubberamunda andMooga Sandstones ) from the remainingsequences. These are the sequences in whosedeposition streams played the greatest part.The predominance of kaolinite in these twosequences compared with montmorillonite inthe other sequences could be due to anyone,or a combination, of three reasons:(a) The source material was different.(b) The source material (montmorilIonitic)

was similar, but the different weather­ing regime in the fluvial sands alteredthe clay minerals to kaolinite.

(c) The source material and the surfaceweathering regime were similar, butgroundwater moving through thecoarser fluvial aquifer sands graduallyaltered the montmorilIonitic matrix tokaolinite, ilIite, and chlorite.

There is little evidence to indicate whichof these possibilities is the more likely. Thereare no indications of major tectonic changesuntil post-Mooga Sandstone time, so it isunlikely that there was a change in sourcematerial in the older sequences owing to tec­tonic activity. Climatic changes giving riseto changes of source material cannot be dis­counted, but there is no relevant evidence.

155

APPENDIX 4CLAY MINERALS IN THE MID-JURASSIC TO LOWER CRETACEOUS

SEQUENCE

byN. F. ExoN

In mid- I972 18 core samples from BMRstratigraphic holes in the Surat Basin weresubmitted to the Australian Mineral Deve­lopment Laboratories (AMDEL) for semi­quantitative clay analysis. Standard AMDELmethods were used and a report on themethods and results was prepared by Brown( 1972). R. R. Vine in a BMR file note hadpointed out in 1969 that within the Ero­manga Basin 'individual members and for­mations have consistent distinguishing fea­tures in their clay mineralogy, even thoughabsolute differences are small'. The presentlyreported work was designed to see whattrends might emerge from clay mineral ana­lysis within the Surat Basin. The location ofthe holes is shown in the accompanying map(Fig. A) and their stratigraphy is discussedby Exon et al. (1967) and Exon (1972).The positions of the samples in each hole aregiven in Table A.

The sequences involved, from oldest toyoungest, are the fluvial Springbok Sand­stone, the lacustrine Westbourne Formation,the fluvial Gubberamunda Sandstone, thelacustrine Orallo Formation (all Jurassic),and the fluvial Mooga Sandstone and theparalic Coreena Member (both Early Cre­taceous). The Gubberamunda and MoogaSandstones are important aquifers.

The results are summarized in Table Aand Figures Band C and the main resultscan be outlined as follows:

(a) The assemblages are dominated bymontmoriIIonite or kaolinite, the pro­portions of which show a reciprocalrelation (Fig. B).

(b) The proportions of chlorite and ilIiteare directly related to the proportion ofkaolinite (Fig. B).

(c) MontmoriIIonite is predominant in mostof the samples. Only in the two porousaquifer sequences (the lower part ofthe Mooga Sandstone, and the Gub-

beramunda Sandstone) is kaolinite pre­dominant (Fig. B).

(d) The clay mineral assemblages do notshow any obvious relation to the grain­size of the sediment (Fig. B).

(e) Quartz and feldspar trends run parallel(Fig. C).

(f) Siderite is common in the CoreenaMember, Westbourne Formation, andin the Mooga and Springbok Sand­stones (Fig. C).

(g) Glauconite was nowhere identified,although round green grains of glau­conie were very abundant in sample 12.

DiscussionThe clay mineralogy distinguishes the two

aquifer sequences (the Gubberamunda andMooga Sandstones ) from the remainingsequences. These are the sequences in whosedeposition streams played the greatest part.The predominance of kaolinite in these twosequences compared with montmorillonite inthe other sequences could be due to anyone,or a combination, of three reasons:(a) The source material was different.(b) The source material (montmorilIonitic)

was similar, but the different weather­ing regime in the fluvial sands alteredthe clay minerals to kaolinite.

(c) The source material and the surfaceweathering regime were similar, butgroundwater moving through thecoarser fluvial aquifer sands graduallyaltered the montmorilIonitic matrix tokaolinite, ilIite, and chlorite.

There is little evidence to indicate whichof these possibilities is the more likely. Thereare no indications of major tectonic changesuntil post-Mooga Sandstone time, so it isunlikely that there was a change in sourcematerial in the older sequences owing to tec­tonic activity. Climatic changes giving riseto changes of source material cannot be dis­counted, but there is no relevant evidence.

TABLE A. GENERAL DETAILS OF SAMPLES SUBMITTED TO AMDEL FOR SEMI-QUANTITATIVE CLAY MINERAL ANALYSES

ApproximatePosition

Unit in Unit Clay Colouro! Illite:Sample BMR Depth Thickness (depth below Fraction Clay Kaolinite

No. Borehole (ft) Unit (ft) top) (ft) Lithology (%) Fraction Ratio

72580012 Roma 9 197' 0" Coreena 300 290 Sandstone 13 Greenish-grey 1:372580013 Roma 9 204' 2" Member 300 300 Mudstone 40 Dark brown I: I

72580016 Mitchell 11 347' 3" 100 45 Siltstone 43 Dark brown 1:572580001 Roma 1 378' 3" Mooga 100 20 Sandstone 28 Greyish-brown 1: 1072580002 Roma 1 392' 8" Sandstone 100 30 Sandstone 12 Grey 1:572580003 Roma 1 413' 2" 100 55 Sandstone 11 Light grey 1:10

72580004 Roma 2 36' 8" 400 40 Mudstone 56 Brown 1: 172580005 Roma 2 42' 10" Orallo 400 45 Sandstone 13 Grey 1:272580006 Roma 2 61' 2" 400 65 Siltstone 22 Greyish-brown 1:272580007 Roma 2 69' 8" Formation 400 70 Sandstone 12 Grey 1:172580014 Chinchilla 2A 148' 7" 400 200? Sandstone 33 Fawn

72580008 Roma 7 51' 3" Gubberamunda 100 70 Sandstone 13 Grey 1:472580009 Roma 7 52' 5" Sandstone 100 70 Siltstone 30 Grey 1: 3

72580010 Roma 7 104' 11" Westbourne 250 25 Siltstone 36 Dark brown 1:572580011 Roma 7 158' 0" Formation 250 80 Sandstone 18 Grey 1:5

72580017 Dalby 1 162' 9" Springbok 500 200 Sandstone 11 Grey 1:572580018 Dalby 1 243' 0" 500 280 Sandstone 13 Grey 1:572580015 Mitchell 3 127' 3" Sandstone 33 25 Sandstone 28 Brown

TABLE A. GENERAL DETAILS OF SAMPLES SUBMITTED TO AMDEL FOR SEMI-QUANTITATIVE CLAY MINERAL ANALYSES

ApproximatePosition

Unit in Unit Clay Colouro! Illite:Sample BMR Depth Thickness (depth below Fraction Clay Kaolinite

No. Borehole (ft) Unit (ft) top) (ft) Lithology (%) Fraction Ratio

72580012 Roma 9 197' 0" Coreena 300 290 Sandstone 13 Greenish-grey 1:372580013 Roma 9 204' 2" Member 300 300 Mudstone 40 Dark brown I: I

72580016 Mitchell 11 347' 3" 100 45 Siltstone 43 Dark brown 1:572580001 Roma 1 378' 3" Mooga 100 20 Sandstone 28 Greyish-brown 1: 1072580002 Roma 1 392' 8" Sandstone 100 30 Sandstone 12 Grey 1:572580003 Roma 1 413' 2" 100 55 Sandstone 11 Light grey 1:10

72580004 Roma 2 36' 8" 400 40 Mudstone 56 Brown 1: 172580005 Roma 2 42' 10" Orallo 400 45 Sandstone 13 Grey 1:272580006 Roma 2 61' 2" 400 65 Siltstone 22 Greyish-brown 1:272580007 Roma 2 69' 8" Formation 400 70 Sandstone 12 Grey 1:172580014 Chinchilla 2A 148' 7" 400 200? Sandstone 33 Fawn

72580008 Roma 7 51' 3" Gubberamunda 100 70 Sandstone 13 Grey 1:472580009 Roma 7 52' 5" Sandstone 100 70 Siltstone 30 Grey 1: 3

72580010 Roma 7 104' 11" Westbourne 250 25 Siltstone 36 Dark brown 1:572580011 Roma 7 158' 0" Formation 250 80 Sandstone 18 Grey 1:5

72580017 Dalby 1 162' 9" Springbok 500 200 Sandstone 11 Grey 1:572580018 Dalby 1 243' 0" 500 280 Sandstone 13 Grey 1:572580015 Mitchell 3 127' 3" Sandstone 33 25 Sandstone 28 Brown

• . .. •

50I

100 kmI

•••

157

26°

28°

G~~~L:-:-..:J

D

Rolling Downs Gp

Springbok Sst-Bungil Fm

Precipice Sst-Walloon Coal Meas

Pre-Jurassic sequence

JY BMR strlltigrllphic hole

o Town

Fig. A. Location of BMR stratigraphic holes.

• . .. •

50I

100 kmI

•••

157

26°

28°

G~~~L:-:-..:J

D

Rolling Downs Gp

Springbok Sst-Bungil Fm

Precipice Sst-Walloon Coal Meas

Pre-Jurassic sequence

JY BMR strlltigrllphic hole

o Town

Fig. A. Location of BMR stratigraphic holes.

-VIQC

Siltst SiltstI Sst 1sst

P Ss! I sst

P Sst f sst

Mudst MudstL Sst Sst

Siltst Siltst

L Sst c SstL Sst Sst

P Sst SstP Sst Siltst

Siltst S,ltst

Siltst Sst

L Sst Sst

L Sst Sst

L Sst Sst

Q/A/599LSst= lithic sandstoneI Sst= Non·porous sandstoneP Sst= Porous sandstone

% CLAY CHLORITE ILUTE KAOUNITE MONTMORILLONITE~ ~ 0Z Z w

FRACTION IN~ ~ ! ~

~

~ ~1:

~ ~ >< w w ~.~ ,~

~ ~ ..J ~ ~~WHOLE >- .5 ~ .: ~ ~ .5 ~

~ ~ ~~~ CL ~

~

~~ ::J Cl ~ 5:*g~ ] CL

=~ ~~ e -"- o-E_j

~ 0 In~

~

~~

1:~ ~ ~~

~ InSAMPLE 0

~ S2~~~ ~ 0

~0 ~ w weJ: .g2 ~ ~ ~ :i tl ~ "§~ ~ :l: ~ ~ (J) (J) ::J

~ .3 :t .:t~~~ .3 u , " .3 (J)0 50 100 :t ,:: « _ ~""4- '" ,:: ,:: c:(~(I)...L. u '" :t >- <t e (/}d-'"

L Sst SstMudst Mudst

w 0..J 000 Zoo::I: '"w ~~a: ~.

0E;;o~ "In cn~

Rom. 9. No 11

Rom. 9. No 13

Roma 7. N;;; 08

Roma 7, No 09

Roma 1. No 01

Roma 1. No 02

Roma 1. No 03

Roma 2. No 04Roma 2. No 05

Roma 2, No 06

Roma 2. No 07Chinchilla 2A, No 14

Roma 7. No 10Rem. 7, No 11

Oalby 1. No 17

Oalby 1. No 18

M'tehell3, No 15

UNIT

MOOGA

SANOSTONE

COREENA

FORMATION

ORALLO

FORMATION

SPRINGBOK

SANOSTONE

WESTBOURNE

FORMATION

GUBBERAMlINOA

SANOSTONE

Sst= Sandstone Sltst= Siltstone Mudst= Mudstone f= fine c= coarse

Fig. B. Relative abundance of clay minerals. (Based on BMR stratigraphic holes).

-VIQC

Siltst SiltstI Sst 1sst

P Ss! I sst

P Sst f sst

Mudst MudstL Sst Sst

Siltst Siltst

L Sst c SstL Sst Sst

P Sst SstP Sst Siltst

Siltst S,ltst

Siltst Sst

L Sst Sst

L Sst Sst

L Sst Sst

Q/A/599LSst= lithic sandstoneI Sst= Non·porous sandstoneP Sst= Porous sandstone

% CLAY CHLORITE ILUTE KAOUNITE MONTMORILLONITE~ ~ 0Z Z w

FRACTION IN~ ~ ! ~

~

~ ~1:

~ ~ >< w w ~.~ ,~

~ ~ ..J ~ ~~WHOLE >- .5 ~ .: ~ ~ .5 ~

~ ~ ~~~ CL ~

~

~~ ::J Cl ~ 5:*g~ ] CL

=~ ~~ e -"- o-E_j

~ 0 In~

~

~~

1:~ ~ ~~

~ InSAMPLE 0

~ S2~~~ ~ 0

~0 ~ w weJ: .g2 ~ ~ ~ :i tl ~ "§~ ~ :l: ~ ~ (J) (J) ::J

~ .3 :t .:t~~~ .3 u , " .3 (J)0 50 100 :t ,:: « _ ~""4- '" ,:: ,:: c:(~(I)...L. u '" :t >- <t e (/}d-'"

L Sst SstMudst Mudst

w 0..J 000 Zoo::I: '"w ~~a: ~.

0E;;o~ "In cn~

Rom. 9. No 11

Rom. 9. No 13

Roma 7. N;;; 08

Roma 7, No 09

Roma 1. No 01

Roma 1. No 02

Roma 1. No 03

Roma 2. No 04Roma 2. No 05

Roma 2, No 06

Roma 2. No 07Chinchilla 2A, No 14

Roma 7. No 10Rem. 7, No 11

Oalby 1. No 17

Oalby 1. No 18

M'tehell3, No 15

UNIT

MOOGA

SANOSTONE

COREENA

FORMATION

ORALLO

FORMATION

SPRINGBOK

SANOSTONE

WESTBOURNE

FORMATION

GUBBERAMlINOA

SANOSTONE

Sst= Sandstone Sltst= Siltstone Mudst= Mudstone f= fine c= coarse

Fig. B. Relative abundance of clay minerals. (Based on BMR stratigraphic holes).

alA/GOD

COMMENTS

+-- Non-clays dominant

...... Non-clays dominant

<iI- Non-clays dominant

FELDSPAR CALCITE DOLOMITE SIDERITE

% QUARTZ

J~

~!

i~

i~

~ ~ ~ ~ j c j ~~

10i = ~ " ~j " "c

~.c ~ III i! J ~.~

" J .c .~ J .~

10 20 30 : Jl Q : """ '" Q : .= Jl Q : .= Jl Q

Roma 7, No 10Roma 7, No 11

Roma 2, No 04Roma 2, No 05

Roma 2, No 06

Roma 1, No 07Chinchilla 1A, No 14

Roma 7, No 08

Roma 7, No 09

Mitchell 11, No 16Roma 1, No 01

Roma 1. No 02Roma 1, No 03

Oalby 1, No 17

Oalby 1, No 18

Mitchell, No 15

Roma 9, No 12

Roma 9, No 13

UJ..JoJ:UJa:oco

UNIT

SPRINGBOK

SANDSTONE

MOOGA

SANOSTONE

ORALLO

FORMATION

COREENA

FORMATION

WESTBOURNE

FORMATION

GUBBEAAMUNOASANOSTONE

Fig. C. Proportions of non-elay minerals in clay fraction.

alA/GOD

COMMENTS

+-- Non-clays dominant

...... Non-clays dominant

<iI- Non-clays dominant

FELDSPAR CALCITE DOLOMITE SIDERITE

% QUARTZ

J~

~!

i~

i~

~ ~ ~ ~ j c j ~~

10i = ~ " ~j " "c

~.c ~ III i! J ~.~

" J .c .~ J .~

10 20 30 : Jl Q : """ '" Q : .= Jl Q : .= Jl Q

Roma 7, No 10Roma 7, No 11

Roma 2, No 04Roma 2, No 05

Roma 2, No 06

Roma 1, No 07Chinchilla 1A, No 14

Roma 7, No 08

Roma 7, No 09

Mitchell 11, No 16Roma 1, No 01

Roma 1. No 02Roma 1, No 03

Oalby 1, No 17

Oalby 1, No 18

Mitchell, No 15

Roma 9, No 12

Roma 9, No 13

UJ..JoJ:UJa:oco

UNIT

SPRINGBOK

SANDSTONE

MOOGA

SANOSTONE

ORALLO

FORMATION

COREENA

FORMATION

WESTBOURNE

FORMATION

GUBBEAAMUNOASANOSTONE

Fig. C. Proportions of non-elay minerals in clay fraction.

160

There is evidence of volcanic activity (tuffa­ceous bentonites) in the Orallo and West­bourne Formations, and it could be arguedthat the montmorillonitic sequences werederived from contemporaneous volcanic ash,whereas the kaolinitic sequences werederived from basement rocks such as gran­ites, volcanics, and metasediments.

However, the simplest explanation is thatthere was little change in the source mater­ial, at least until Coreena Member time, andthat the differences are due to alteration dur­ing and after deposition. The original clayswould then have been largely montmoril­lonite, which Papadakis (1969) states canbe produced from almost any source rocksby leaching at a low temperature, or by slowleaching in a cold or dry climate, or both.

Stream deposits laid down on alluvialplains would be subject to repeated rework-

ing and weathering, and with a generalregime different to that in the hinterland,montmorillonite could alter to kaolinite. Thelacustrine and paralic sediments would beless reworked and more quickly buried, leav­ing the montmorillonite unchanged.

Alteration of the stream sediments bygroundwater after they were buried would bepossible if there was sufficient pore space toallow water to penetrate through sandstoneswith a montmorillonitic matrix, despite anyswelling of the montmorillonite. This couldcertainly occur in the common coarser sedi­ments, which may have contained littlematrix originally. Water flowing throughcoarser beds could gradually have alteredthe clays of adjacent finer-grained sedimentsto kaolinite, allowing even greater penetra­tion of the water into previously monmoril­lonitic beds.

REFERENCES

BROWN, R. N., 1972-Clay analysis of 18 bore- EXON, N. F., MILLlGAN, E. N., CASEY, D. J., &hole samples. AMDEL Report MP5659/72 GALLOWAY, M. C., 1967-The geology of the(unpubl.). Roma and Mitchell I: 250 000 Sheet areas,

ExON, N. F., 1972--Shallow stratigraphic drilling Queensland. Bur. Miner. Resour. Aust. Rec.in the eastern Surat Basin, Queensland, 1966, 1967/63 (unpubl.).1967 and 1968. Bur. Miner. Resour. Aust. PAPADAKIS, J., 1969-SOILS OF TIlE WORLD. Am-Rec. 1972/54 (unpubl.). sterdam, Elsevier.

R75/874

160

There is evidence of volcanic activity (tuffa­ceous bentonites) in the Orallo and West­bourne Formations, and it could be arguedthat the montmorillonitic sequences werederived from contemporaneous volcanic ash,whereas the kaolinitic sequences werederived from basement rocks such as gran­ites, volcanics, and metasediments.

However, the simplest explanation is thatthere was little change in the source mater­ial, at least until Coreena Member time, andthat the differences are due to alteration dur­ing and after deposition. The original clayswould then have been largely montmoril­lonite, which Papadakis (1969) states canbe produced from almost any source rocksby leaching at a low temperature, or by slowleaching in a cold or dry climate, or both.

Stream deposits laid down on alluvialplains would be subject to repeated rework-

ing and weathering, and with a generalregime different to that in the hinterland,montmorillonite could alter to kaolinite. Thelacustrine and paralic sediments would beless reworked and more quickly buried, leav­ing the montmorillonite unchanged.

Alteration of the stream sediments bygroundwater after they were buried would bepossible if there was sufficient pore space toallow water to penetrate through sandstoneswith a montmorillonitic matrix, despite anyswelling of the montmorillonite. This couldcertainly occur in the common coarser sedi­ments, which may have contained littlematrix originally. Water flowing throughcoarser beds could gradually have alteredthe clays of adjacent finer-grained sedimentsto kaolinite, allowing even greater penetra­tion of the water into previously monmoril­lonitic beds.

REFERENCES

BROWN, R. N., 1972-Clay analysis of 18 bore- EXON, N. F., MILLlGAN, E. N., CASEY, D. J., &hole samples. AMDEL Report MP5659/72 GALLOWAY, M. C., 1967-The geology of the(unpubl.). Roma and Mitchell I: 250 000 Sheet areas,

ExON, N. F., 1972--Shallow stratigraphic drilling Queensland. Bur. Miner. Resour. Aust. Rec.in the eastern Surat Basin, Queensland, 1966, 1967/63 (unpubl.).1967 and 1968. Bur. Miner. Resour. Aust. PAPADAKIS, J., 1969-SOILS OF TIlE WORLD. Am-Rec. 1972/54 (unpubl.). sterdam, Elsevier.

R75/874

APPENDIX 5

WIRELINE-LOGGING OF WATER-BORES IN THE SURAT BASIN,

1960 to 1974

by

N.F. EXON and JEAN MORRISSEY

CONTENTS

SUMfo.lARY

INTRODUCTION I

THE LOGS 2

STRATIGRAPIIY 4

THE Ti\13LES 5

TIlE AQUIFERS 8

REFr:RENCES 10

TABLES

1. Surat Basin: generalized stratigraphy

2. Consolidated aquifer statistics of all bores logged

3. Consolidated aquifer statistics for bores logged, by1:250 000 Sheet areas

4. Water properties of various aquifers

5. Bore nwnbers related to Sheet areas

6. Water-hares 1n the Eddystone Sheet area

7. Water-bores 1n the Taroom Sheet area

8. Water-bores 1n the Mundubbera Sheet area

9. Water-bores 1n the Mitchell Sheet area

10. Water-bores 1n the Roma Sheet area

11. Water-bores 1n the Chinchilla Sh~~t area

12. Water-bores In the Homeboin Sheet area

13. Water-bores 1n the Surat Sheet area

14. Water-bores 1n the Dalby Sheet area

15. Water-bores 1n the Dirranbandi Sheet area

1G. Water-Lares 1n the St George Sheet area

17. Water-bores 1n the Goondiwindi Sheet area

FIGURES

1. Regional geological setting

2. Conductivity of aqueous solutions of NaCI

3. Graphical presentation of water chemistry

4. Flow rates of flowing bores from var~ous aquifers

5. Cross-section across basin to show major aquifers

6. Map showing distribution of aquifers

11

13

14

16

17

19

20

21

22

23

25

26

27

28

30

31

32

(ii)

PLATES

}-.LocaLi ty map

Structure contours, top of IValloon Coal ~leasures

3. Gcullma-ray/neutron log: Reg. No. 11739

4. Differential temperature log: Reg. No. 11739

S. Correlation of water-bores: Roma to Moonie area

SUMMARY

Between 1960 and 1974, 264 \vat er-bores Clnd 20 petrol ewn exp lorat ion

wc 11 s convc rt ed to wat er-ha res were logged in the Surat Basin, predominant1y

in Queensland. Most logging was done by or for the eureau of i'-lineral

Resources to provide both stratigraphic and hydrological information. Both

flowing and non-flowing bores were logged; the basic scale used was

1" = 100 feet (1: 1200), and logs at a scale of 5" = 100 feet (1:240) were

also commonly run.

Gamma-ray logs are available for all the bores listed, illld neutron,

temperature, differential temperature, flowmeter, and casing collar locator

logs arc available for many. Typical logs are presented.

The bores are inde:\ed by thei I' Regis tered Numbers, as given by the

Queensland Irrigation and \'later Supply Commission and the NSW Water Conserva­

tion and Irrigation Commission. Their localities are plotted on a base map

at a scale of 1:1 000 000. A complete list In numerical order of all bores

logged, related to the 1:250 000 Sheet area In which they fall, is provided.

For each Sheet area the bores are listed in numerical order, with converted

petroleum wells separately listed in alphabetical order, and the following

statistics are tabulated where available: name, elevation, depth drilled,

depth logged, logs available, salinity, the unit the bore spudded in, the

deepest aquifer presently tapped, the water level for non-flowing bores, and

the flow rate for flowing bores. The aquifer statistics are consolidated for

each Sheet areq, and for the basin as a whole.

Water samples from many bores were chemically analysed by the

Government Chemical Laboratory in Brisbane, and the analysis sheets are held

at the Bureau of Mineral ReSOurces. Water quality for six major aquifers is

summarized graphically by plotting total dissolved solids against the

IICO;/Cl ratio for the western and eastern parts of the basin. This prelim­

inary work has shown the potential of chemic~l analysis to distinguish between

aquifers.

The logging has enabled reliable stratigraphic and aquifer correla­

tions to be made throughout the basin, in conjunction with information from

petroleum exploration wells. A gamma-ray correlation line is presented to

illustrate the stratigraphic use of the data, and the correlations have been

extensively used in a stratigraphic review of the basin.

-b-

The chemical data, in combination with estimates of flow rates,

have revealed the characteristics of l;:8 major aquifers of the eastern and

western sides of the basin. Flo\v I'ates arc higher and water quality is gen­

erally better In the west than IT. the cast, al though the Pill iga Sandstone in

the sout heast y i c Ids exce 11 ent wat er and is probab ly the most product i vc

aquifer. The depth to the ::;hallowest major aquifer never exceeds 900 Ili.

iNTRODUCTION

Bet\'Jeen E)()O and 1974, 26'1 wat~r-bores and 20 converted petrolewll

exploration wells in the :Jurat Bdsin (Fig. 1) were wireline-10ggeJ for the

Bureau of ['-lineral Re~,OUl"CCS (BMR) in co-operat ion \1/ i th the Queer:s LlIld

I rrigat ion and Wat Cl' Supp ly Commissi on and the Geo 1ogi cal Survey ,.)f Queens land

(GSQ). BMR officers c~rrip lout the early work, which proved the value of

the method, but later programs were carried out by private companies under

contract to BMR. The air.l of the proj e'.::t was to:

a) Provide stratigraphic information of benefit to BMR-GSQ geological

field parties and oil company geologists;

b) Provide hyclrological information of beneEi t to hydrologists and

engineers dealing with large-scale and small-scale problems \vithin

the Great Artesian Basin.

Pioneering work was carried out by BM~ in 1960 and 1962, USIng

gamma-ray and temperature tools. The 1960 program; during which 11 bores and

2 pet 1'01 eum well s \vere gamma-ray logged in the Surat Bas in, was report ed by

.lesson, Radeski, cr .lewell (1963). The 1962 program, when a further 16

water-bores were gamma-ray logged in the Surat Basin, was reported by .lesson

Cl Re.deski (1964). Thi s worK showed that correlat ior. of gamma-ray logs of

water-bores was fairly reliable when the bores were s?aced less than 25 km

apart. 1I0wever the 'temperature logs were of little practical value because

the bores were !lot in a static state while being logged' (.lesson & Radeski,

Ope cit.).

In late 1964, Schlumberger gamma-ray logged a number of water-bores

In the northwestern Surat Basin aDd eastern Eromanga Basin for American

Overseas Petrolelml Pty Ltu, and the results suggested that the conventional

correlation of the Hooray Sandstone/Upper Intermediate Series/Adori Sandstone

of the Tambo area v!ith the Mooga Sandstone/Grallo Formation/GubberamlITlda

Sandstone of the Roma area was probably incorrect. The correlation was later

confirmed by field work and palynological studies. Transparencies of the

Schlumberger logs were given to BMR, and copIes can be Jbtained from the

address given below.

-2-

In I9b7/bi) a nCI'; program of logging began in the Eromanga and Surat

Basins \vith Down Under Wcll :;ervices wot'king under contract to l3~m. Initially

the standard log~; run Iverc gamma-ray and casing colla:t locator, and electric

and flo\vJJleter-caliper logs in sui.table bores. During the contr3ct a

temperature-differential temperature log was addeJ, and proved to be a most

lIseful tool for aquifer studies. In the Surat Basin few logs \vere rLm in this

year, the bulk of the \vork being done in the Erom~U1ga Basin.

1963/69 the program continued using the S~UIlC cor:tractor, working

mainly i.n the lIomeboin, llirranbandi, and St Georgo 1:2.50 000 Sheet areas in

the southiVesten1 Surat Basin. In 1970/71 logging was extended into the

Goondiwincli, Dalby, Chinchilla, Surat, RomLl, and ~litchelJ Sheet areas. In

1969/70 and 1971/72 t he re \vas no logging in the Su rat Basin.

In 1972/73 Down Under Well Services logged 45 bores In the Dalby

and Goondiwindi Sheet areas in the southeastern Surat Basin. They used a

neutron log in addition to those used in the e,tr1ier work. In 1973/74 Down

Under Well Services completed coverage of t~:p. Queensland portion of the Surat

Basin by logging 54 bores in the Taroom, Mundubbera, Chinchilla, ~\l1d Roma

Sheet areas i.n the northeastern part of the basin. Prints of the rarious

logs are available from:

The Copy Service,

Government Printer (Production),

1'.0. Box 84,

CANBERRA. A.C.T. 2600.

THf LOGS

Typical g0J11ma- ray, neutron, temperat ure, di fferential ternperat ure,

and casing collar locator logs are shown in Plates 3 & 4, and a gamma-ray

correlat ion of \vater-bores between Rorna and Moonie IS shown In Plate 5. The

basic scale is I" = lOO' but for iIlany bores logs at a scale of 5" = 100' are

also available. The quality of the wireline logs is generally excellent.

Where drillers' logs of the bores exist these have been added to the ganuna­

ray log by the Queensland Irrigation and Water Supply Commission.

The gaJllllla-r:1)' tool measures the natural Lldiation of the strata

penetrated, and the apparatus produces a log showing the intensity of raJia­

tion in APl units at 0.11 depth~;. Clay minerals have relatively high radiation

I.,:hereas quartz and feldspar grains have low radiation. Thus quartzose s:1J1d­

stones give 101',1 values, whereas lithic sandstone, siltstone, and shale give

high values. The g<UJlllla-ray log is the best stratigraphic tool available for

holes which are cl-sed, and IIllist bores logged arc cased for most of their

depths.

1:1ectric logs are only valuable \;,Ilere there is no casing, and hence

Eel;' electric logs ha'/e b2cn run. The electric logs consist of a self-poten­

tial curve recorded in millivolts, anJ resistivity curves recorJed in ohmsI

m~· Im.

The neutron log is produced by a high-energy neutron source which

bombards the rocks penetrated, and a detector which captures :md records those

neutrons which have been sufficiently slowed (moderated) by collision with

other part ides. The most .~fficient moderator is hydrogen, which in the

sequences penet rat cd is common on ly in wat er. Thus n eut ran logs measure

mo is ture content above the war er-t ab 1e and tot 0.1 porosity be low the wat er­

table. Hence they are of both hydrological and stratigraphic use. Higher

values In API LL'1its indicate higher moisture content or greater porosity.

Flowmeter-caliper logs measure the revolutions per second of a

propeller and the diameter of the hole, from which the flow per second 1n the

bore can be calculated. With the tools employed Lmtil recently, the technique

was effective only in rapidly flowing bores as the rotor in the current meter

was unreliable at low rates. An improved tool now allows low flow rates to be

measured. The logs indicate the position of the maj or aquifers in lfficased

bores and allow their flows to be calculated. In cased tares they indicate

the position of perforations in the casing, and increase or decrease of flow

rates by ga1n or loss of water through the perforations.

TI1e temperature-differential temperature logs are valuable for

aquifer studies and have been run in most bore-holes. A sensor measures the

temperature (oC) as it is lowered into the borehole. This temperature is

marked directly onto the temperature log. It is also stored on the memory of

the ins tnunent and compared with the t emperat ure 15 cm deeper; the resultant

temperature differential is recorded continuously: giving the differential

temperature log, which is more sensitive than the normal temperature log.

-4-

When \vater entc's the hole at any level i': is normally cooler than \vater

l'iSlIlg lip the boreholcfroill below that level. In a few bores noted in the

Et'omanga Basin, hot \\later has m..I..:e its \vay into a higher aquifer, probably

along a fault, and anomalously Ill.gh values arc than reconled from the

aquifer. The differenti.al temperature log records the entry of water through

perforations in the casing (or directly from the sediment in w1caseu bores)

from the various aqui fers, and for larger flows the actual change of the

water temperature is recorded on the temperature log.

The casing collar locator is nm in conjunction with the other

logs. It provides a depth reference in the hole, enables the other logs to be

correctly interpreted, and gives direct information about the state, "md

presence or absence of the caSIng. We use the simplest type, which consists

of a permanent magnet wrapped In a cod of wire. Changes in the magnetic

flux cause a small current to flow in the wire, and the current:s re CO "!:'jed.

At the casing collars there is much more steel than elsewhere in the casing,

and the increase in magnetic flux is marked by peaks on the log. Where the

casing has parted, or in the cOlJunonly uncaseJ part of the hole in the lowest

aqui fer, no events are recorded. This informat ion is import ant in that the

presence or abs ence of cas ing affect s t he gamma-ray and n eut ron 10 gs.

Furthermore if a large part of the hole is uncased, electric logs can use­

fully be run. For the property owner the casing ~ollar locator log shO\\Is

the state of the casing, and whether repairs are needed.

STRATIGRAPHY

The Jurassic and Cretaceous Surat Basin (Fig. 1) fOTITIS most of the

(; as tern part of the hydnJlC)~ical Great Art es ian Bas in, and its sediments are

similar to those of the Eromanga Basin to the west, with which it inter­

tongues across the Nebine Ridge and its broad southerly extension the

Cunnamulla Shelf. It is bounded to the south by the Central West Folded

Belt, to the east by the New England Fold Belt, the Moreton Basin, and the

Auburn Arch, and to the north it has been eroded.

The basin is a simple depression with up to 1200 m of marlne and

paralic Lower Cretaceous sediments which are generally aquicludes, and up to

1700 m of freshwater Jurassic and lowermost Cretaceous sediments which con­

tain several excellent aquifers. The structure is illustrated by contours

on the top of the Walloon Coal Measures (PI. 2), which horizon lies about

-5-

ha! fway up the aqui f(:r sequence and covers lI1os1 of the ha~;in. The Surat Bilsin

sequence 1 ios on rocks ranging in age froll1 lJevunian to i'-Ilddlc Triassic, and ll1

composition froll1 ~ranite, schist, and gneis~; to undeformed sedill1ents. The

stratigraphy of the Surat Basln sequence LS SLUJllIIarL:ed in Table 1; nomen­

c 1 :lturc used 15 based on that of Exon (1971).

TI lE TABLES

Tables 6 to 17 detail information for bores from each 1:250 000

Sheet area; each bore is located in Plate 1. The various headings in the

tables are discussed below. Consolidated statistics for all bores cmd for

bores by Sheet areas arc presented in Tables 2 and 3.

1) Reg. No. The Registered ::ulIlber 1S the number issued for each bore, by

the Queensland Irrigation and Water Supply Commission in most cases. In cases

where Cl subheading 'NSW Bores' appears, the nLUnbers are those issued by the

New South Wales Water Conservation and Irrigation Commission. Considerable

data on th~ bores arc available from these organizations e.g. strata pene­

trated, water supplies at various levels, details of bore casings.

2) Name. Names are appliecl to the bores by their owners, and recorded by

the two water supply commissions.

3) Eleva.tion. The elevation above mean sea level of the ground surface at

the bore, measured in feet and converted by us to metres, is recorcled where

it is aVililable. In some cases this comes from original water-bore records,

In others frem the contractors who carried out the logging.

4) .Qepth dri lIed. The depth dri 11 ed in feet as measured by the dri 11 er was

recorcled by the two commissions, and we have converted this to metres.

5) Depth loggecl. This depth was recorded, i:l feet, by the wireline-logging

cont ractor for each log run. Under this heading we hA-ve noted the number of

metres logged with che gamma-ray tool, unless by some mischance this log was

not run, in i.;hich case th8 l1lunber of metres from the differential temperatu::.e

log is recorded. In many bores the depth logged IS considerably less than

the depth drilled; this generally means that there is an obstruction in the

hole. Commonly the holes were cased for only the upper part of their depth,

and have caved in below the casing. In some bores the clepth logged is

greater than the recorded clepth drilled; this generally means that the hole

has been cleepened since it was originally clrillcd, and commission records

have not been updated.

.. ()-

The 10(lS av,li tahle V,ll'y frOlIl hole to hole.'"

The symhols

used in this co lumn a rl~:

(; :::

N :::

Ut :::

T :::

I: :::

F ::

gamma ray log

/lCut ron log

Tcmperature-Lli fferent ial temperature log

tcmperature log ,11011C

electric log (below casing only)

flowmeter-caliper log

In almost all holes a caSing collar locator log was also run.

7) Salinity. For some bores the salinity of the water has been measured

electrically both in the field and in the laboratory, and conventional

chemical an,Llyses have also been carried out, mostly by the C;overnment

Chemical Labora to ry in Br isb ane.

The 'analysed T. D. S.' co 1wnn reco rds the total dis sol ved sol ids in

parts per million (ppm). In many cases this has b~en calculated by us,

simp ly by adding toget he r the val ues for all the ions ,mal ys cd in the

laborl1tory.

The 'conductivity', measured electricl111y in j1S/cm, of some seunples

has been recorded in the field, and of others in the laboratory. Field

recordings arc denoted by 'F', and laboratory recording by 'L'. As field

readings arc a better record of the water as it emerges from the bore, they

have been preferred wh0re two figures are available for one bore.

The 'field salinity' was measured by the contractor with an instru­

ment \\rhich converted the electrical data directly into its equivalent value

in terms of sodiwTI chloride (NaCI) salinity in parts per million. This

value does not imply that the NaCl content of the water is that recorded,

because other salts are always present and are commonly dominant. It merely

implies that an NaCl solution of this concentration would give the measured

electrical response. Thus the 'field salinity' bears a direct relation to

the conductivity (which can be determined graphically - Fig. 2). 1he temper­

ature is of great importance to these calculations, and values are normally

expressed at 25 0 C.

The IlCO:/Cl column records the ratio between the bicarbonate anc/..)

chloride ions in the water (in terms of chemical equivalents). These are the

dominant ions, and hence this ratio is important. Values less them one mean

-7-

that ch1ol'ide is dominant, h'hcrc:ls vallll's greater than onc IlIe:l/l that biGl/"-

honate is dominant. In the artesian aquifers ~:l!IC:O_ is dominant, \vhereas III,)

the relatively unproductive subartesiilI1 aquifer'S within the H,olling Downs

(;roup and the lnjune Ct'eek Croup l\JaCl is Jomin:lllt.

Total dissolved solids has been plotted against the IICO;/C1 ratio

for individual bores in Figure 3, yielding useful information abollt the

Vat'iOlls aquifers. From the chemical analyses held at 13MR much more could be

learnt. about water quality, but such a study is outside the scope of the

present report.

S) Spudded 111. The unit. III which the bore 'spudded' (i ,Co the lmit first

penetrated) is recorded in this collunn. Fat" bores in which substant.ial

<'ullounts of Tertiary (T), Caino:oic (Cz), or Quaternary (Q) sediments overlie

the ~lesozoic sediments, both groups are recorded. Post-Mesozoic sediments

arc as much as 200 In thick in places, and conmlOnly yield subi.lrtesi~m water.

The symbo 1s arc expl a ined in Table l.

9) Deepes t aqui fe r presen t.ly tapped. This co 1UTIln records t.he deepest impor­

tant aquifer which today yields water in each bore (symbols explained in

Table 1). In many bores this is the most important aquifer.

Many bores have caved in below the casing, or have been deliberc...tely

plugged below a cer!ain depth, so that deeper aquifers which were originally

penetr~ted no longer affect the bore. In genera.l we have a.ssumed that water

is not being derived from aquifers below the depth which was logged, on the

grounds that if the relatively ::>Jl\all logging tool could not penetrate any

deeper, the hole was blocked.

10) Water-level. 1he water-level has been recorded in metres below the

ground surface, whe re avai labl e. In bores where wat e r is flowing ou,,: at th,:;

surface the term 'flow' has been used. In cases where water has to be

pumped, but the wat er-l eve 1 has not been recorded, the t enn 'pump' has been

used.

Where the water is flowing out at the surface, estimated flow rates

(m 3/day) have been included (1000 gallons per day = 4.546 m3/day). In most

bores these estimates were made by the log operator or property owner at the

time the bore was logged, but sometimes they are the original estimates of

the drill er. In bo;~es where orig iIlal and recent es t imat e~ are avai lab1 e,

flow rates appear to have declined considerably with time. Although these

estimates arc not particularly accurat~, it is apparent from plotting them

(Pig. 4) that taken in lJillk they arc ~nformative.

TilE i\Qll I FI:I<S

The gcner;Ilizations in the following section ;il'e based on the a ss LUll"

ptioll that the deepest ;\quifcl' presently t'lppeu in each bore provides the

gr,:at hulk of the water in the bore. This is true in many but not all bores.

Some features of the water chemistry of the main ;Iquifers in the

Surat Basin arc plotted in l:igllre 3, and estimated flow rates ;\re plotted in

Figul'c ,~. Th.::;se data arc sLUJll1larized in Table 4. ACfuifc;'s \vest of 1490

have

been sepurated from those cast of 1490

to demonstrate the changes across the

b;lsin. The intC'rrelations of the aquifers arc shOlm in Figure j, and the

distribution of the m:ljor aquifers and the depth to the Ilooray cmd Mooga

Sandstoncs, which generally contain the shallmvest supplies, arc shown in

Figure 6.

The water chcmis::ry i<lS beell :iW!lJllarizeu by plotting totul dissolved

solids (ppm) against ~he IlCO:/CI- ratio. The ;malyses provided by the.)

Co"crnlllcnt Chemical Laberatory in Brisbane have shO\vn that the dominunt

cat; on is sodiLUIl (N,,/), emu that the dominant anions are chloride (Cl ) ;md

bicarbonate (I1CO;). In most aquifers i1CO~ predominates over C1-) and the

ratio can he informative. The Cl ion is dominant only in some of the

aqui fers of the Inj une Creek Group, and In ;Ill the aqui fers 111 the Rolling

Downs Croup. Thus low I1CO:/ C1- rat ios suggest that the bulk of the water is.)

coming fr'om an aqui fe r or aqui fers 1n thest. uni ts. Furthermore general

salinity is 11ighest in these units, and any inflow 1~:''l1 them into bores draw­~

lng mainly from other aquifers could be expected to increase the salinity.

Figure 3 suggests that it may te difficult to separate the various

major aquifers on the btsis of water chemistry. In the west the salinity in

terms of total dissol ved sol ids ranges from 500 to 1650 ppm, and the

IICO:/Cl ratio frolIl almost 0 to 6.5. Of the major aquifers the Gubberamund;.t,)

Sandst one appears to conta in \vat er of the least sal ini ty. The sal inity

values \vhere the lIooray Sandstone is assumed to be the maj or aqui fer show the

greatest variability, probably because aburldant highly saline water from the

Rolling Downs Group is making its way into some bores.

In the east the major aquifers tend to deliver water of greater

salinity,

700 ppm ­

richer in

,lI1d the I1CO:/C1 ratio is highly variable (total dissolved solids,)

2200 ppm; IICO:/C1 ratio 0.6 - 17.6). 111e weter is generally,)

bicarbonate in the east (average IICO:/C1 ratio about 4) than in~

-9-

the west (about 2). The least salin0 water comes from the oldest aquifer and

the most sal ine from the youngest (Pi 11 iga Sandstone av. 900 ppm, Gubberamunda

Sandstone 1200 ppm, ~Iooga Sandstone 1700 ppm).

The plot of estimated flow rates (Fig. 4) shows that ~ .eplies vary

from aquifer to aquifer, illld from west to east. TIle most prolific aquifers

are the Hooray Sandstone In the west, and the Pi11iga Sandstone in the south­

east, with maximwn supplies about 5000 m3/ day, and average supplies about

2500 m3/day. The percentage of flowing bor8s in these two aquifers (Table 2)

is also higher than average. The Gubberamunda and r.looga Sandstones are also

excellent aquifers with high flow rates in the west (Gubberamunda maximum

4000 m3/ day, average 2500; Mooga maximum 3000, aver'age 1500), but much

lower flow rates in the east where there are many bores with low flow rates

and many subartesian bores. In general these aquifers are deeper where they

are tapped in the west than in the cast, and the potentiometric surface is

higher, so the greater flow rates may depend solely on hydraulics. The older

Hutton and Precipice Sandstones are seldom tapped in the deeper part of the

basin, despite the high flow rates suggested by data from petroleum explora­

tion wells. The Adori Sandstone yields abundant good-quality wa~er, but is

confined to the far west of the basin.

To sWllmarize for the eastern side of the basin, the Mooga Sandstone

provides poor to satisfactory supplies of moderately good water at reasonable

depths. Similar supplies of better water can be obtained from the Gubbera­

munda Sandstone, which is normally 100 to 200 in deeper. The best supplies

and best water come from the Pilliga Sandstone, which is only slightly deeper

than the Gubberamunda Sillldstone but is confined to the area south of

Goondiwindi and Inglewood.

On the western side of the basin water quality is generally good,

and excellent supplies are available from the shallowest major aquifers, the

Hooray and Mooga Sandstones. Similar supplies are also available from the

deeper Gubberamunda Sandstone.

The generally higher salinity and bicarbonate content of the east:­

ern waters are probably related to higher carbonate concentrations in the

intake areas and the aquifer sandstones themselves. The eastern aquifers

derive their water fromlreas in the northeast and southeast where carbonate­

rich soils are common; in contrast, the western aquifers derive their water

from areas in the north where carbonate-poor soils predominate. Furthermore,

-10-

the sandstones of the eastern aquifers are generally less mature :..md contain

more lffistable 'minerals, including carbonates, than do those of the western

aquifers.

In many places in the deeper parts of the basin, costs prevent prop­

erty owners dri 11 ing as deep as the maj or aqui fers, and they make use of com­

paratively small saline supplies of subartesian water from the RaJ ling Downs

Group or Bungil Format ion. The depth to which they would have to drill to

reach the Mooga Sandstone is as much as 800 m north of Talwood (Fig. 6).

REFERENCES

DAVIS, S.N., El DE WIEST, R.J.rvl., 1966 - HYDROGEOLOGY. N.Y., Wiley.

EXON, N.F., 1971 - Rama, Qld - 1:250 000 Geological Series. Bur. Miner.

Resour. Aust. exp1an. Notes SG/55-12.

JESSON, LE., & RADESKI, A., 1964 - Great Artesian Basin bore logging,

Queensland, 1962. Bur. Miner. Resour. Aust. Rec. 1964/103 (unpubl.).

JESSON, E.E., RADESKI, A., &JEWELL, F., 1963 - Great Artesian Basin experi­

mental bore logging, saut hwes t Queens land, 1960. Bur. Miner. Res our.

Aust. Rec. 1963/103 (unpubl.).

-11-

TABLE 1. SURAT BASIN GENERALIZED STRATIGRAPHY

Age UnitMaximumthickness

(m)Environment and

lithologyGamma-ray log

characterWater Relations

Grirnan Creek Formation 480 Paralie and freshwater: Generally low values: Minor aquifers:KIg sandstone, siltstone, variable* sal ine

rnudstone

Surat Siltstone 150 Marine: siltstone, Fairly high val ues : AquicludePo< Kls mudstone, sandstone consistent;j

Early 0Coreena MenJber 210 Para1ic and freshwater: Moderate values: Minor aquifers:H

L9(Wallurnbilla Formation) siltstone, mudstone, variable saline

t/)

§ Klc sandstone0Cl

Cretaceousb.O

270 Marine: mudstone; High values: Aquiclude~ Doncaster Member'Mrl (Wallurnbilla Formation) some si ltstone consistentrl0 KId~

B . 1 F .ungl.!. ormatlonKly

Cadna-owie FOlwation Kle

Hooray Sandstone JKh

270

100

400

Freshwater and paralic:mudstone, siltstone,sandstone

Paralic: siltstone,sandstone

Freshwater: sandstone;some siltstone

Moderate values:variable

Moderate values:variable

Generally low values

Some aquifers

Some aquifers

Major aquifers

Eastern equi­valent of Kle

Wes tern equi­valent of Kly

Jurassic Mooga Sandstone 300 Freshwat er: sandstone; Variable values: Maj or aquifersKlm some siltstone, mudstone some very low

toaralIa Formation 270 Freshwater: labile sand- Variable values: some Minor aquifers

Juo stone, siltstone, rnud- very highearliest stone, coal

Gubberamunda Sandstone 300 Freshwater: sandstone; Low values: fairly Maj or aquifersCretc:lCeOLlS Jug some siltstone, cong- consistent

lomerate

Pilllga Sandstone Jp 300 Freshwater: sandstone,conglomerate

Low va.lues: consistent Ma.jor aquifers Southeasternequival ent 0 fJuw &Js

Age Unit

Westbourne FormationJuw

Springbok SandstoneJs

Maximumthickness

(m)

200

250

--12 -

Environment andlithology

Freshwater and possiblyparalic: si It stone,mudstone, sandstone

Freshwater: labilesanJstone, siltstone,mudstone

Gamma- ray 10gcharacter

High values: consis­tent

Generally low values

Water

Aquiclude

Minor aquifers

Relations

Eastern equi­valent of Ja

Generally high values: Aquicludevariable

Jura~;sic

to

earliest

Cretaceous

(1)

§'r-.~

H

Adori SandstoneJa

Walloon Coal MeasuresJw

Eurombah FormationJrne

100

650

100

Preshwater: quartzosesandstone, siltstone

Coal measures: labilesandstone, siltstone,mudstone, coal

Freshwater; sandstone;some conglomerate,siltstone, mudstone

Low values

Very variable values

Maj or aqui fers

Minor aquifers

Wes tern equi~

valent of Js

Maj or aquifersHutton SandstoneJlh

Evergreen FormationJle

250

260

Freshwater: sandstone;some siltstone, mudstone

Freshwater and paralic:siltstone, mudstone,sand~tone

Generally low values:variable

Generally high values: Some aquifersvariable

Precipice SandstoneJlp

150 Freshwater: quartzose Generally low valuessandstone; some siltstonemudstone

Maj or aquifers

* 'Variable' or 'consistent' refers to vertical variation ln anyone log.

-13-

TABLE 2. AQUIFER STATISTICS FOR ALL BORES (INCLUDING PETROLEUM EXPLORATIONWELLS) LOGGED

StatusDeepest aquifer presently tapped Number ofbores Flowing

boresPumpedbores

~o Flowingbores

Hooray Sandstone (JKh) 3S 29 A 83

~looga Sandstone (Klm) 73 60 13 82

Gubberamunda Sandstone (Jug) 62 32 30 S2

Pilliga Sandstone (Jp) 19 18 1 95

Hutton Sandstone (Jlh) 47 10 37 22

Precipice Sandstone (J Ip) 17 5 12 28

Other 31 7 24 23

TOTAL 284 161 123 56

1:250 000Sheetarea

-14-

TABLE 3. AQUIFER STATISTICS FOR BORES LOGGED, BY SHEET AREA

Deepest aquifer presently tapped Status

Hooray rvtooga Gubber- Pi1liga Hutton Precipice Other Flow Pump,UTIunda

(Jkh) (Klm) (Jug) (Jp) (Jlh) (Jlp)

Eddystone

'faroom

Mundubbera

Iv!i t che 11

Roma

Chinchilla

1

61

17

3

6

2

22

1

13

3

4

5

7

5

2

2

6

5

42

3

2

21

1412

2

12

183

14

41

111

3516

12415

Homeboin 16 15 11 1

3 33 1 2

8 4 4

Surat 76

11

531

23

1

-15-

TABLE 3 (contd)

1:250 000Sheetarea

Deepest aquifer presenLly tapped

lIoo ray Mooga Gubber- rill iga Button Precipiceumunda

(Jkh) (KID) (Jug) (Jp) (Jlh) (.lIp)

Other

Stat us

Flow Pump

Dalby

Dirranbandi

St George

2615

124

2

65

16

3

1

222

12421

65

15

413

3

1

Goondiwindi 8 7 17- 16 7.... .)

3 33 1 2

TABLE 4. WATER PROPERTIES OF VARIOUS AQUIFERS

AquiferMaxi~um supply

(m / day)west east

ToLl 1 dissol ved sol ids(ppm)

west east

11(0- /Cl­ra€io

west east

Griman Creek Low Low High High Chloride dominantFormation Klg

Corecna ~Iember Lmv Low High High Chloride dominantKlc

Bungil Format ion Kly Low Low Moderate Moderate Bicarbonat eand Cadna-owic dominantFormJ.tion Kle

Hooray Sandstone 5350 Absent 600-1600 Absent 0.54 AbsentJ-Kh

~looga Sandstone 3150 1350 600-1600 1350-2200 1.4-5.0 0.8-8.2IOm

Gubberamunda 4100 2300 650-900 850-2100 1. 4-3.6 0.6-11. 0Sandstone Jug

Adori Sandstone 2650 Absent Absent AbsentJa

Pilliga Sandstone 5000 Absent 750-1000 Absent 2.7-4.4Jp

Hutton Sandstone 500Jlh

Precipice Sandstone 500Jlp

High = 200 ppm

Moderate = 1500-2000 ppm

Absent = aquifer absent

- means no informat ion available

west = west of 1490

east = east of 149 0

-17-

TABLE S. BORE NU~lBERS RELATED TO 1: 250 OUO SIlt:ET AREAS

10 Surat 3477 Ilomcboin 11950 Goondiwindi

24 IIomeboin 3819 Dirranbandi 11954 IIomeboin37 Ilome bo in 3820 Di rranbancli 11995 Goondiwindi

39 IIomeboin 3850 Rorna 12088 Goondiwindi

40 IIomeboin 3851 Ronw 12106 Mi tchell

55 Dirranbandi 3852 Rorna 12136 Chinchilla

59 St George 3979 r.li t che 11 12158 Goondiwincli

62 Dirranbancli -I () 28 St George 12188 Chinchilla

64 Dirranbandi 4042 Dirranbandi 12190 Dal by

73 St George 4043 St George 12236 Taroom

89 IIomeboin 4044 St George 12278 Dalby97 Ilomeboin 4045 St Georgc 12421 Roma

106 St George 4051 Surat 12447 Dalby

127 Surat 4052 Surat 12565 Dalby

132 St GeorgL: ~053 S'lrat 12569 Dalby

133 St [--orgc 4135 bldys tone 12631 Goondiwindi

1.":)4 St Gcorge 4257 Roma 12633 Dalby147 Dirranbandi 4399 St George 12639 Goondiwindi

149 lIomeboin 4401 St George 12700 Roma150 lIomeboin 4585 Mitchell 12702 Goondiwindi

167 Dirranbandi 4587 Homeboin 12714 Goondiwindi

168 Homeboin 4687 f'.1it che1l 12741 Mi tchell

285 ~Ii tchell 4918 Dirranbandi 12814 Taroom

303 Roma 12883 Homeboin387 ~Ii tche 11 4920 Dirranbandi 13030 Dalby388 Mi tche 11 4921 Dirran bandi 13038 Roma

397 St George 4999 Homeboin 13139 Da1by1482 Homeboin 8551 Goondiwindi 13140 Dalby1483 lIomeboin 8654 Homeboin 13155 Roma

1485 Homeboin 10284 Goondiwindi 13180 Mundubbera

1599 r-.litchell 10479 Roma 13248 Roma1600 r-.litche11 10809 Chinchilla 13300 Goondiwindi

1601 Mi tche 11 10841 Roma 13471 Chinchilla

1603 r-.li tche 11 10984 Mit chell 13455 Da1by1604 Mitchell 11051 Homeboin 13518 Chinchi lla

1605 Mitchell 11287 Mitchell 13586 Dirranbandi

1609 Mitchell 11306 Mundubbera 13682 Da1by

1610 Mi tchell 11354 Eddystone 13710 Dalby

1773 Eddystone 11410 Surat 13744 Goondiwindi

2339 Roma 11421 Da1by 13757 ChL.... chi Ha

2340 Roma 11434 Taroom 13809 Da1by

2414 Dirranbandi 11492 Chinchilla 13820 St George

2621 Mitchell 11495 Surat 13878 Chinchi Ha

2622 Mitchell 11501 Taroom i3882 Mundubbera

2623 r-.li tchell 11523 Dal by 13936 r-.li tche112686 Di rranbandi 11555 Dalby 13951 Mi tche 11

2762 Homeboin 11560 Roma 13999 Goondiwindi

2770 IIomeboin 11645 Goondiwindi 14027 Roma2822 Goonc.liwindi 11701 Chinchilla 14141 Da1by2883 IIomeboin 11739 Taroom 14190 Taroom

2884 Homeboin 11740 Surat 14204 T2-room

2973 St George 11743 Goondiwindi 14307 Roma

2975 Homeboin 11754 r-.litchell 14388 Taroom

2976 lIomeboin 11758 Taroom 14506 Chinchi lla3475 lIomeboin 11857 Homeboin 14598 Mundubbera3476 lIomeboin 11866 Homeboin 14609 Taroom

-18-

'1'1\ BLE 5. (C 0 nt d • )

Converted petro lewn exp loration we lIs

Roma

DalbySuratDalbyDalbyGoondwindiDalby

DalbyDalbyChinchi 11aSt George

Chinchi llaDalbyDalbyDalbyDalby

SuratDalby

Davidson No. 11Dock eri 11 No. 1Dogwood No. 1Kent ucky No. 1Lat CIJIO re Eas t

No. 1 ROll1aU.K.I\. Mt Driven No. 1 St George1\. R. O. No. 19

(IV Cl 11 wnbill a)U. K.I\. ~Ioonie North

No. 1U.K.I\. Paloma No. 1U.K.I\. Retreat No. 1U. K.A. Tey No. 1U. LA. Tingan No. 1U.K.A. Widg2wa No. 1

U.K.I\.U.K.A.U.K.I\.U. K.A.1\.1\.0.

NSW Bores

U.K.A. Alton West No. 1U.K.A. Bennett No. 2M. O. C. No. 1 (Boyanda)U.K.I\. Burunga South No. 1U.K.I\. Cobbareena No. 1U.K.A. Currajong No. 1U.K.A. Crowder No. 1U.K.A. Crowder East No. 1

16 788 Di r ran ban cl i1683/ [)irranbancli16984 Dal by17070 Tar-oolll17191 ROllla17236 ROllla17385 Dal by174)5 Dal by17511 Dalby17689 Dal by17877 Goondiwincli117987 Dalby18083 Dalby22140 Goondiwindi30054 Ta1'0 0111

30316 Dalby30346 Dalby30535 Tarooll130788 Tarooll131127 Goondiwindi31293 Goondiwindi31371 Chinchilla31489 Chinchilla31860 Dalby32735 Taroom33283 Taroolll34768 Goondiwindi34814 Goondiwindi35251 Dalby35458 Taroom36075 GoondiwindiNew Bore Taroom

4024 St George4032 St George4099 St George4121 St George4132 St George4163 St George4185 St George4578 Goondiwindi4611 St George4685 St George

Tar-oolllSt GeorgcDalbyRomaChinchillaTaroolllSuratHomaSuratSuratDalbyTaroom1l0lJ1eboinGooncliwindiRomaGoondiwindiDirranbandit'-lundubberaChinchil~a

1I0mcboinTaroomHundubberaGooncliwindiGoondiwindiChinchi 11aRomaTaroomGoondiwindiTaroomSuratGoondiwindiMundubberaGoondiwindiRomaRomaTaroomDalbyRomaRomaGoondiwindiGoondiwindiGoondiwindiChinchillaDalbyDi rranbandjGoondiwindiGoondiwindiDalbyTaroomTaroomRomaSuratRomaMundubbcraDi rranbandiDi rranbandi

14680147121474214810H85714861149061493D1503615101151241517115183151801530215465154731548715508155231552515590156241566315670156961.57281597616000160291603916065161401617416204162251623416235162641627516281163541640016445164761650316524165001658916607166311665416684166861673516783

-19-

TABLE 6. WIJ{ELINE-LOGGED WATER-BORES IN 'THE EDDYSTONE 1:250 000 SIIEET i\I~Ei\

Reg. Depth Depth Logs i\nalysed Sal ini ty Deepest Water-levelNo. Name Eh~vation drilled logged available T.O.S. Conduct- Field

HC0 3Spudded aquifer

Cm) (m) Cm) G,N,Ot, (ppm) ivity salinity presently IIIlnEX -

T F ( S/crn) (ppm r:l (emp) tapped (fSows in, ,L ,. Na Cl) m / day)l',

1773 Wallace's 50S 244 233 G KId Jkh PUlnp

41S5 Woolshed No. 2* 539 274 208 G Jmb ,J1h rump

11354 Kari l'A- 561 245 239 G Jmb Jlh Pump

* Schlumberger logs run for A.merican Overseas Petroleum

X See text for explanation

..

-20-

TABLE 7. WIRELINE-LOGGED WATER-BORES IN rlHE TAROOM 1 :250 000 SHEET AREA

Reg. Depth Depth Logs Analysed Sal ini ty Deepest Water-levelNo. Name Elevation uri 11 ed logged available T.O.S. Conduct - Field

HCO;Spudded aquifer

(m) (m) (m) G,N,Dt~ (ppm) ivity salinity 111 presently mEX -T F, ( Si cm) (ppm Cl (emp) tapped (flows 1n,

L,F NaCl) 3m Iday)

11434 Roche Dale 305 234 G.N. Dt. 4,500 Jw Jlh 9

11501 Bangildoon 466 431 G.N. Dt. Jw Jlh 14

11739 Langdale 611 593 G.N. Jw Jlh 46

11758 Belle Eau 329 327 G.N. Dt. Jlh Jlp 34

12236 Broaumere No. 4 293 266 G.N. Dt. 350 Jw Jlh 9

12814 Moss Vale 365 513 G.N. Dt. Jw Jlh 7

14190 Alkoomie No. 2 312 309 G.N. Jw Jlh 52

14204 Wainui No. 2 373 362 G.N. Dt. 1,100 .Jw Jlh 30

14388 Bimbadeen 371 356 G.N.Dt. 500 Jw Jlh 43

14609 Rushian No. 2 350 168 G.N. Dt. Jlh Jlh 49

14680 Acacia Plateau 285 28 GN. Dt. Jw Jlh 40

14861 G 261 G. Js? Jlh Pump

15171 G 238 257 G. Jw Jlh Flow

15525 Robinson Creek 319 275 G.N. Dt. Jlh Jlh 80

15728 l~ayfield No. 3 338 235 G.N. Dt. 1,700 Jw Jlh 30

16000 Bridge Creek No. 3 274 549+ G.N. Dt. Jw Jlh 44

16225 Cudgee 767 744 G.N. Dt. Jw Jlp 39

16589 Carra 498 473 G.N. Dr .. 900 Jw Jlh IFlow

16607 Kinnoul G 596 596 G. .Jw Jlh Pump

17070 Mooriand No. 4 323 322 G. Dt. Jlh Jlp Flow (90)

30054 Yurnga 1 299 239 G. N. Dt.E. Jlh Jlh 52

30535 Illuka 579 493 G.N. Dt. Jw Jlh 62

30788 Verbena PJ.rk 305 304 G. N. Dt. 300 Jlh Jlh Flow

32735 Taroom Town G 685 685 Jw Jlp Pump

33282 305 297 G.N. Dt. 800 Jw Jlh Flow (13)

35458 463 459 G.N. Dt. Jw Jlh 17

New Bore New Bore 1052 G.N. Dt. 100 Jw Jlp Flow (455)

G = Logged by GSQ; logs available fr0m B:-isb ane

x = See text for explanation

-21-

TABLE 8. WIRELINE-LOGGED WATER-BORES IN THE MUNDUBERRA 1:250 000 SHEET AREA

Reg. Depth Depth Logs Analysed Sal ini ty Deepest Water-levelNo. Name Elevation drilled logged available T.O.S. Conduct - Field

HCO;Spudded aquifer

(m) (m) (m) G,N, Dt, (ppm) ivity salinity presently mInx -T, F, E ( Si cm) (ppm Cl (emp) tapp,'d (fJows in

L,F NaCl) 3m I day)

11306 Bentley Park 335 351 G.N. Dt. 150 Jlh Jlp Flow (33)

13180 Pontypool No. 2 395 392 G.N. Dt. Jlh Jlp 31

13882 Cluehead No. 2 235 372 227 G.N. Dt. Jle Jlp Flow (small)

14598 Knockbine No. 3 425 346 G.N. Dt. Jlh Jlp 78

15487 Daldownie 599 593 G.N. Dt. Jw Jlp 31

15590 Beaumont 274 271 G.N. Dt. 100 Jlh Jlp Flow (32)

16065 BungablID 258 390 291 G.N. Dt.E. Jlh .Jlh 7

16686 Knockbine No. 5 320 385 G.N. Dt. Jlh Jlp 60

x See text for exp lanation

-22-

TABLE 9. WIRELINE-LOGGED WATER-BORES IN THE MITCHELL 1:250 000 SHEET AREA

Reg. Depth Depth Logs Analysed Salini ty neepest Water-levelNo. Name Elevation dri 11 ed logged available T.D.S. Conduct- Field HC03

Spudded aquifer m(m) (m) (m) G,N,Dt, (ppm) ivity salinity j_ J.I presently

T F EX ( Si cm) (ppm Cl (erop) tapped (flows in, ,L,F NaClj 3

day)III I

285 Muckadilla 358 1147 109 G. Klc Klm? 3387 Mitchell Town Bore* 336 916 905 G. KId Jhl Pump

388 Morven Town Bore"k 429 807 810 G. KId Jlh Pump

1599 Pamassus* 394 1044 1020 G. Klc Jlh Pump

1600 Woolshed* 363 922 919 G. Klc Jlh Flow, ceased

1601 Bonus Downs* 363 923 922 G. Klc Jlh Flow, ceased

1603 Oolandilla Creek* 372 874 869 G. Klc Jlh Flow, ceased

1604 Annie Vale 356 977 179 G. Klc Jkh Pump

1609 Cytherea No. 1* 355 897 881 G. Klc Jlh Flow, ceased

1610 Cytherea No. 2 367 1039 937 G. T. Klc Jlh Pump

2622 Washpool Creek 351 835 833 G. Dt. 569 720L 340 2.11 Klc Js Flow (45)

2623 Washpool Creek 383 966 550 G. Dt. 573 720L 350 2.09 KId J ? 21s.

3979 Crochdantigh 354 891 890 G. Dt. Klc Jlh 4

4585 Leinster* 358 889 888 G. Klc Jlh Flow, ceased

4687 Woolshed No. 2 342 549 389 G. KId Jkh Pump

10984 Horse Creek* 347 216 171 G. Juw Jlh Pump

11287 Ourella 306 298 G. 1658 2800L .009 T/Kld Jkh Pump

11754 Ounkfeld 359 357 G. Ot. 750 Cz/Klc Jkh Flow (90)

12106 Leinster West 427 408 G. Klc Jkh Pump ?

13936 Bullagai 335 328 G. Ot. 1259 1675L 850 1. 19 Klc Jkh Flow (small)

13951 Mi tche 11 No. 2 890 887 G. T. KId Jlh Flow

2621 Eure1la Creek* 351 1151 1101 G. Klc Jlh Flow (small)

Schlumberger logs run for American Overseas Petroleum

X See text for explanation

-23-

TABLE 10. WIRELINE-LOGGED WATER-BORES IN THE ROMA 1:250 000 SHEET AREA

Reg.No. Name Elevation

(m)

Depthdrilled

(m)

Depthlogged

(m)

LogsavailableG,N,Dt,'[ F F

X, , ~

Ana lysedT.D.S.(ppm)

Conduct ­ivity

( S/ cm)L,F

Sal ini tyFieldsalinity(ppmNaCl)

HCO~.)

CI-(emp)

DeepestSpudded aquifer

in presentlytapped

Water-level

m

(flows In3

m / day)

303 Roma Railway 316

2339 Coinda 327

2340 Delmally No. 2 347

3850 Mt Abundance No. 1

3851 Mt Abundance

1129

666

823

497

393

638

173

729

G

G. Dt.

G. Dt.

G. Dt.

KId

KId

Klc

Klc

Jug'?

Js?

Kly?

Jug

Pump

37

58

4257 Roma Downs 320

10479 Wandoan Test No. 7 243

10841 Combarngo 267

No. 116A

3852 Lochiel

11560 Roundhole

12421 Taunton

12700 Wallabella No. 4

13038 Oakland No. 3

13155 Wandolin No. 2

13248 Rippon Lea

13816 Coolabong

14027 Dalkeith No. 2

14 307 ~Ioraby

365

297

295

294

282

280

285

308

1181

284

496

655

500

611

342

366+

497

348

570

358

482

520

494

94

361

334

492

604

329

318

486

329

523

357

466

518

G. Ot.

Dt.

G. N. Ot.

G. T.

G. T.

G.

G. T.

G. N. Dt.

G. Ot.

G. T.

G. T.

G. N. Ot.

G. Ot.

G. Ot. 1561 1790L 950 3.69

KId

KId

KId

Juw

T/Kls

Js

Klc

Klc

Js

Klc

T/Klc

Klc

KId

T/Klc

Jug?

Kly

Klm

Jlh

Klm

Jlh

Klm

Klm

Jlh

Klm

Klm

Klm

Jug

Klm

Flow

Flow

Pump

Flow

Flow

Flow

Flow

Flow

Flow

29

5

21

(9.1 )

36

30

(90)

14810 Forest Grove

No. 2 290

Dundonnell No. 4 281

Deep Water

Klc Klm?

Q/Klc Klm

T/Klc Klm

T/Klc Klm

Cz/Klc Klm

KId Klm

14930

15302

15696 .J ackbore No. 2

16174 Salisbury Creek

16204 Pine Hills

16235 Camelot

16264 Moira Runda

16631 Iona 294

568

640

405

621

564

477

518

612

366

426

329

400

264

562

474

497

603

360

G. N. Ot.

G. N. Dt.

G. Dt.

G. Ot. 1350

G. Ot. 1756

G. Ot. 1954

G. Dt.

G. Dt. 1535

G. N. Dt.

1650L

1870L

2670L

1740L

900

950

1400

870

850

1. 90

6. 70

0.92

3.34

Klc

Klc

T/Klc

Klm

Klm

Kly?

Flow (f)80)

11

18

Flow (small)

Flow (small)

Flow (90)

Flow (90)

Flow (90)

Flow (1365)

TABLE 10 (contd)

-24-

Reg. Depth Depth Logs Analysed Salinity Deepest Water-levelNo. Name Elevation drilled logged available LD.S. Conduct- Field

I-ICO;Spudded aquifer m

(m) (m) (m) G,N,Dt, (ppm) ivity salinity in presently-T F EX ( S/ cm) (ppm Cl (ernp) tapped (flows ln, ,L,F NaCl) 3

m / day)

16()84 Bardloming

No. 2 290 326 226 G.N. Dt. Klc Kly 4

17191 Maffra No. 1 275 591 567 C.N. Dt. Klc Jug Flow

17236 Maffra No. 2 281 587 534 G.N. Dt. Klc Jl'g 1

Petroleum Wells

405

14431

A.R.O. No. 19

A.A. O. Latemore

East

318

312

1511

457

559

341

G.

G. N. Dt.

Kly

KId

Js?

Klm

Pump

18

x See text for explanation

-25-

TAB LE 11. IV lIU:LI NE- LOCCU) WATEH- BO!{!:S AND CONVER'J'I:D PETROLFUM IV ELLS 1N TilE Clll NelIl LLA

1:250 000 SIIEET AREA

Hog. Depth Depth Logs Analysed Salinity Deepest Water-levelNo. Name Elevation drilled logged available T.D.S. Conduct - Field

IICO;Spudded aquife~

(m) (m) (m) G,N,Dt, (ppm) ivity salinity presently m1nT F r: x -( S/cm) (p pIll Cl (eIllp) tapped (flows 1n, , ."

L,F NaCl) 3 .rn /day)

10809 Staines Par 71 369 718 G. Dt. .J Kk .lIp 16

11492 Butter ractoryNo. 1 325 200 G. Dt. Jw Js 18

11701 Coolall\unda 218 198 G. Kly Juo Pump

12136 Binbian Plains 301 313 290 G.N. Dt. Kl c KIm 40

12188 Redbank 288 381 37() G.N. Dt. T KIm rlow (10)

13471 lIell Ilole 315 333 308 G.N. Dt. .Jlh JIh 61

13518 Glenolive 301 407 370 G.N. Dt. Klm Jug 9

13757 lVieambilla 303 317 279 G.N. Dt. Jug? Js 15

13878 Brigalow 315 397 385 G.N. Dt. T/.Jw JIm 12

14506 Bawnduggie 319 376 344 G.N. Dt. .lIe .lIe 102

14857 Dundee No. 2 303 439 401 G.N. Dt. T/KIc KIrn Flow (14)

15508 Glen LaurelNo. 5 544 S39 G. Dt. Jug JIh 34

15670 Ride c~ SonsBore 324 374 338 G.N. Dt. KIm Jug 42

16400 Golden Valley 329 457 465 G.N. Dt. Cz/.ls .lIh 35

31371 Tangy Park 920 918 G. Dt. E. 790 Js .lIp Pump

34227 Weringa 357 405 G.N. Dt. Jw .lIp 76

Petroleum Wells

8406 M.O.C. No. 1(Boyancla) 326 1439 730 G. Dt. Juo ,IIh 0

22541 U. K. A. BurungaSouth No. 1 318 2598 761 G.N. Dt. Jw .lIp 54

22395 U. K.A. DogwoodNo. 1 297 1261 1247 G. Dt. Juo .lIp 36

x Sce text for explanatiC'n

-26-

TABLE 12. IVIRELINE-LOGt;ED WATER-BOIU:S IN TilE HOtvlEBOlN 1:250 000 SIII:I:'1' AREA

168 Yunnerman

8654 Coolaman

2883 Grassmere No. 1

1482 Binda No. 1

1483 Binda No. 2

10

21

(227 )

21

30

(2545)

(3635)

(1590 )

(Large)

(2270 )

(1135 )

(1590)

( 455)

(2270 )

26

(2270 )

(1820)

(45 )

(small )

(4000)

Pwnp

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Pwnp

III

Pwnr

Pwnp

Flow

Water-l.evel

Flow

Flow

Flow

Flow

Flow

Flow

Flow

3In I day)

(flows in

De cpest<lquiferpresentlytapped

.1kh'?

Ja?

.Ja?

Ja?

Spudded111

CZ/ Klg Jug

Cz/KIg Jug

Czl Klg ,Jkh

Czl KIg ,Ja

cz/Klg .Jlh

CzI Klg .Jllg

CzIKlg .Jkh

CzI Klg ,Ja

Q/ Klg .Jkh

KIg? .Jkh

CzI Kls .Jkh

CzI Kls .1kh

.Jkh

Cz/KIg Klm

CzI Kls .1a

Cz/KIg .1kh

Cz/Kls .1kh

Klg? .1a

KIg? .Ja

Kle

Kle

Kle

Kle

Cz/Klc Jlh

Cz/ Klc .Jkh

Cz/Klc Jkh

Cz/ Klg Klm

Cz/Klc .Jkh

Cz/Klc .Jkh

Cz/Klg .Jkh

Cz/Klc Jkh

1.96

2.04

1. 37

2.09

3.05

1.44

2.94

1. 20

2.16

1. 70

0.22

0.97

0.07

1. 39

IICO;

CI-(emp)

2.29

360

500

350

370

470

500

430

340

580

400

350

400

550

750

700

800

Salinity

1250

Fieldsalinity(ppmNaCI)

631 F

880 F

825 F

720 F

870 L

1210 F

990 F

2850 L

1020 F

660 F

737F

770 F

1320 F

1540 F

600 F

885 L

2640 F

Conduct ­ivity

( S/cm)L,F

733

1063

1126

1284

AnalysedT.D.S.(ppm)

G. Ot. F.

G.

G. Ot.

G. Ot. F. 595

G. Ot. F.

G.

G. Ot. 1753

G. T.

G. Ot. 904

G. T.

G. Ot. F. 689

c. Ot. F. 889

G.

G. Ot. F. 604

G. Dt. F. 733

G. Dt. r. 686

G. Dt. F. 834

G. Ot. F. 795

G. Dt. F. 708

G. T.

G. Ot.

G. Ot.

G. Ot.

G. Ot.

G. Ot.

G. Ot.

G. Ot.

G. Ot.

G. T.

G. Ot. F.

G.

LogsavailableG,N,Dt,'1', F, EX

727

305

213

507

573

695

943

559

552

236

971

777

164

239

610

403

853

290

319

617

299

402

290

930

921

1066

1066

1364

955

605

1011

Depthlogged

(m)

303

792

920

939

853

856

549

708

991

536

847

305

946

321

608

931

408

346

369

1077

1068

1370

954

1016

777

680

490

595

563

951

989

Depthdrilled

(m)

224

246

2·14

230

7)7

213

197

335

7..27

210

237

231

211

210

320

309

290

247

260

244

290

279

194

259

Elevation(m)

Name

AbbiegIassie

Albany Downs

Tangy No. 1

3476

24 Chippe\\lay

37 Cypress

39 Powrunna

1485 Bindebango No. 2

2762 FoyIe View

2770 ~Iaranda Downs

40 Neabull

62 lIopelancl Trust

89 ~Iaroungle

97 Mona Trust

1.49 Weirbolla

150 Wild (lorse

2884 Grassmere No. 2

2975 Ilomeboin No. 2

2976 lIomeboin No. 3

3475 Abbieglassie

No. 1

3477

4587

4999

Ikg.No.

11051 lbomoo No. 4

11857 Begonia No. 2

11866 Gunnawarra

11954 l~lIochard

12883 LulIworth

15183 Tongy 4

15523 Chesterfield

No. 2 242 1437 1157 G. Ot. F. Cz/Klg JIh Ab<U1doned

x See text for explanation

-27-

TABLE 13. WIRELINE-LOGGED WATER-BORES AND CONVERTED PETROLEUM WELLS IN 1HE

SURAT 1:250 000 SHEET AREA

Reg. Depth Depth Logs Analysed Salinity Deepest Water-levelNo. Name Elevation drilled logged available LD.S. Conduct- Field

HC03Spudded aquifer

(m) (m) (m) G, N, Dt, (ppm) ivity salinity presently mIn, x - (flows in1, F, E ( Si cm) (ppm Cl (emp) tapped

L,F NaCl) 3m I day)

10 Borah 334 1476 1465 G. Dt. F 1080 1150 L 6.53 Klc JIh Flow (365)

127 Thomby 229 1213 1212 G. Dt. F. 600 Klg Jug Flow (2270)

4051 Noorindoo No. 1 1058 825 G. Dt. KIg KIm? 37

4052 Noorindoo No. ') 267 946 780 G. Dt. Klg 1(lm 3....

4053 Noorindoo No. 3 272 1049 1047 G. Dt. KIg Jug 5

11410 Canmaroo 777 664 G. Dt. 2202 2340 L 550 3.86 KIg KIm Flow (36)

11495 Kilburnie 440 418 G. Dt. T/Kls Kly 3

11740 Woodlands 277 599 566 G. Dt.Cal 1881 2000 L 1050 4.81 T/Kls Klm Flow (small)

14906 Corack 861 854 G. Dt. 2081 2150 L 5. 78 Klg Jug? Flow (small )

15036 Meandarra Town 282 1123 1121 G. Dt. 550 KIg Jug 15

15101 Pongi 725 717 G. Dt. 1766 2000 L 7.35 Klg K1m Flow (45)

16029 Stirling Park 610 588 G. Dt. F. 1979 2050 L 550 5.29 Klg Klm Flow (365)

16654 Innisvale 732 726 G. Dt. 500 KIg K.;m Flow (small )

Petroleum Wells

U.K.A. Alton

West No. 1

U.K.A. Paloma

No. 1

213

305

2097

2334

1255

1229

G. Dt.

G. Dt.

500 Klg

Klg

Jug

Jug

Flow (590)

19

x Sce text for explanation

-,c.o-

'fABLE 14. WIRELINE-LOGGEO WATER-BORES AND CONVERTED PETROLEUM WELLS IN 'HIE

OALBY 1:250 000 SHEET AREA

Reg.No. Name Elevation

(m)

Depthdri 11 ed

(m)

Depthlogged

(ill )

Logsavailable

G,N,Dt,T F EX, ,

AnalysedT.O.S.(ppm)

Conduct­ivity

( S/ cm)L,F

SalinityFieldsalinity(ppmNaCl)

BCO:.')

Cl-(emp)

SpuddedIn

Deepestaquiferpresentlytapped

Water-level

m

(flows Inm3/ day)

11421

11523

11555

12190

12278

12447

12565

12569

12633

13030

13139

13140

13455

13682

13710

13809

14141

14742

15124

16234

16445

16550

16984

17385

17435

17511

17689

17986

18083

30316

Lomond Downs

Bathampton

Wahroonga No. 1

Thuruna No. 2

Wahroonga No. 2

Warroon

Cabawin

Greenfield

Warroon No. 2

Strathalbyn

Bramston

Bellevue Park

Barramornie No. 3

Barramornie

The Oaks

Belara

Tara Town No. 2

Inverness

Moonie Weir

Warrowa

Coradon

Pippinford

Talinga

Ringwood Park

Curraj ong No. 3

Willara

Burnbrae

The Deep

Gilgi

273

290

290

282

312

325

518

342

368

427

610

393

602

549

644

339

458

541

567

535

524

611

456

334

762

408

674

607

544

869

466

655

743

375

643

322

507

330

369

407

565

370

598

540

630

373

439

533

534

527

496

555

438

308

760

726

635

584

4"/6

825

462

643

728

329

624

G. N. Ot.

G.N. Dt.

G. Dt.

G. N. Dt.

G. N. Dt.

G. Dt.

G. N. Dt.

G. N. Dt.

G. N. Dt.

G. T.

G. N. Dt.

G. T.

G. T.

G. N. Dt.

G. N. Dt.

G. N. Dt.

G. N. Dt.

G. N. Dt.

G. N. Dt.

G. Dt.

G. N. Dt.

G. Dt.

G.N. Dt.

G. Dt.

G. Dt.

G. Dt.

G. N. Dt.

G. N. Dt.

G. Dt.

G. N. Dt.

1691

2004

1585

2366

1877

2006

1912

1780

1980

2042

1812

2019

2032

1746

1977

1850

1423

5366

1321

1840 L

2820 L

1720 L

3680 L

1990 L

2160 L

2070 L

2140 L

2160 L

2100 L

2010 L

2160 L

1925 L

1820 L

2090 L

2725 L

1520 L

9500 L

1650 L

10S0

1700

2700

870

1250

1100

1250

1100

1100

1000

750

800

1050

920

900

1100

1700

950

6000

900

6.38

1.13

4.62

0.37

5.14

8.17

5. 72

3. 76

8.05

6.46

10.99

5.83

7.37

17.61

7.38

0.62

4.28

0.04

3.19

KId

Cz/Kls

Cz/Klc

Cz/Kld

Cz/Klc

Cz/ Klc

Cz/l<:lc

Cz/Klc

Cz/Klc

Cz/Klc

Cz/Kld

Cz/Klc

Cz/Kls

Cz/Kls

Cz/ Klc

Cz/Klc

KId

Cz/Klc

Cz/Klc

Cz/KIc

Cz/KIs

Cz/Kls

Cz/Kld

Cz/ Kl c

Cz/Kls

Cz/ Klc

Cz/Kld

Cz/KIc

Cz/KId

Cz/Klc

Klm

Kly

Kly

Klm

Klm

Klm

Klm

Klm

Klm

Klm

KIs

Klm

Klm

Klm

Klm

Klm

Jug

Klm

Kly

Jug?

Jug

Klm

Jug

Klm

KIlT.

Klm

Jug

Jug

Klm

Klm

Flow (small)

31

29

626

Flow (910)

Flow (?)

Flow (small)

Flow (small)

Flow

Flow (small)

Pump

Flow

Flow (36)

Flow (9)

Flow (90)

43

Pump

2

Flow (45)

41

Flow (70)

28

Flow (small)

Flow (23)

Flow (23)

3

35

17

Flow small

TABLE 14 (contd)

-29-

Reg. Depth Depth Logs Analysed Salinity Deepest Water-levelNo. Name Elevation drilled logged available T.D.S. Conduct- Field

HC0 3Spudded aquifer

(m) (m) (m) G, N, Dt, (ppm) ivity salinity presentlym

InT, F, EX -( Si cm) (ppm Cl (emp) tapped (flows in

L,F NaCl) m3I day)

30346 Duffields Bore 506 471 G.N. Dt. 1519 1570 L 1200 5. 71 Cz/Klc Klm Flow (4.5)31860 Tullaville 504 476 G.N. Dt. 1764 2300 L 1400 1.46 Cz/Klc Klm Flow (11)

35251 Biddybrook No. 2 645 629 G. Dt. 1438 1640 L 750 4.14 Cz/Klc Klm Flow (23)

Petroleum Wells

U. K.A. Bennett

No. 2 287 1728 628 G. Dt. Cz/Kld Jug 19

U. K.A. Cobbareena

No. 1 333 1576 422 G. Dt. Kly Jug 41

U.K.A. Crowder

No. 1 261 1787 771 G. Dt. Klc Jl.:.g 5

U. K.A. Crowder

East No. 1 262 1690 764 G. Dt. KId Jug 8

U. K.A. Currajong

No. 1 257 1872 855 G. KIc Jug 4

U.K.A. Davidson

No. 1 284 2293 471 G. Dt. 1200 Cz/KL: K1m Flow [9)

U.K.A. Dockerill

No .. 1 254 1832 497 G. Dt. 850 CzI Klc KIm Flow (45)

U.K.A. Moonie

North No. 1 270 1833 742 G. Dt. Cz/Klc Jug 13

U. K. A. Retreat

No. 1 278 1900 665 G. Dt. Czl Klc Jug 20

U.K.A. Tey No. 1 289 1638 508 G. Dt. 900 CzI KId Jug Flow [405)

U. K.A. Widgewa

No. 1 255 1885 834 G. Dt. KJ c Jug 9

x See text for explanation

-30-

TABLE 15. WIRI:LINE-LOCCr;D WATEI~-BORES IN TIll: IHRRANBANDI 1 :250 000 SHEET AI~EA

Reg.No. Name Elevation

(m)

DepthJrillecl

(m)

Depth10ggeJ

Cm)

Logsavailable

G,N,Dt,T F EX, ,

AnalyseclT.D.S.(ppm)

Conduct ­ivity

( 5/ cm)L,F

SulinityFieldsalinity(p pmNaCl)

HCO;

Cl-(emp)

DeepestSpudclecl aquifer

1n presentlytappecl

Water-level

III

(flows in

m3/elay)

55 Eugcn

64 Ingi e

147 IVhyenbah

1.67 Yanco North

2414 Yamburgan

2686 Queens Bir"'.:hday

3819 Dunbar

3820 Whitably

4042 Narine

4918 Wyenbah No. 1

4920 BUllindigie

4921 Cmvi 1eli

13586 Glendon

217

203

172

222

172

179

191

165

190

184

176

1046

~ 0 13

955

946

641

755

853

944

869

932

914

413

10 12

1013

944

728

921

629

673

651

944

866

913

908

399

G. Dt. F. 761

G• F. Dt • 92 1

G• Ot. F. 652

G. Dt. F. 710

G. Dt. F. 946

G. Ot. F. E. 653

G. Dt. F. 1445

G. Dt. F. 729

G. Dt. 1603

G. Ot. F. 943

G• Ot. F. 116 7

G. Dt. F. 124 1

G. Dt. 9878

770 F

935 F

660 F

715 F

803 F

60S F

1430 F

715 F

1650 F

880 F

1210 F

990 F

16,500 F

600

500

380

400

470

1000

720

410

820

600

600

640

8200

2.06

3.87

2.36

2.09

3.58

2.19

5.39

2.50

4.94

2.69

4.90

5.12

0.025

Cz/ K1g Jug

Cz/ K1g ,Jkh

Cz/KIg Klm

Cz/ KIg Jkh

Cz/ Klg Jug

Cz/KIg Jkh

Cz/KIg Jkh

Cz/Klg Jkh

Cz/KIg Klm

Cz/Klg Klm

Cz/KIg Jkh

Cz/K~g Jkh

CzI KIg Klc

Flow (3410)

Flow (5000)

Flow (2730)

Flow (5230)

Flow (2270)

Flow (5365)

Flow (135)

Flow (1820)

Flow (590)

Flow (1820)

Flow

Flow (730)

Small trickle

(2230 )

15473 Book Book No. 2

16476 Yart 00

880

752

881

751

G. Dt. F.

G. Dt. F.

916

807

803 F

990 F

480

780

3.34

2.84

Cz/KIg Jkh

Cz/KIg .Jkh

Flow

Flow (2760)

16735 Ballandool

No. 2

16783 Calooma

16788 Koomalah

16837 Oban

1036

1315

1097

914

492

1006

823

880

G. Dt. F.

G. Ot. F.

G. Dt. F.

G. Dt. F. 784

660 F

770 F

1430 F

825 F

480

750

400

400 3.03

Cz/Klg Jkh

T/Klg Jkh

KIg Klm

Cz/Klg Jkh

Flow

Flow

Flow

Flow

(1500)

(1~20)

(910)

(2455)

x See text for explanation

-31-

TABLE l(>. IIJrJ{ELrNE-LOGGED WA'J'EH.-BORES AND CONVERTED PETROLEUM WELLS IN Tlll~

ST GEORGE 1:250 000 SHEET AREA

Reg.No. Name Elevation

(J1] )

Depthdrilled

(m)

Depthlogged

(m)

Logsavailable

G,N, Ot ,T, F, EX

J\nalys edToD.S.(ppm)

Conduct ­ivity

( S/cm)L,F

SalinityFieldsalinity(ppmNaCl)

IICO;

Cl-(emp)

SpuddedIn

Deepestaquiferpresentlytapped

Water-level

m

(flows in3m I day)

59

73

106

132

133

134

397

2973

4028

4043

4044

4045

4399

4401

1:' 82 0

14712

Geralda

Kaywanna Trust

Mya11 Plains

Weengallon No. 1

Weengallon Nu. 2

Weenga110n No. 3

St George

lIollymount

Newingar

Noondoo

~laxl ands

Bullwarrie

Boombah

'Dwraggie

Noondoo Trust

Buckinbah No. 2

245

192

199

222

229

200

238

198

174

178

171

197

196

1208

1323

1083

1117

1146

1218

823

914

1100

1093

1087

1101

922

910

1178

932

1204

1320

876

1116

1146

1218

746

898

1098

1049

1077

1101

665

903

1178

925

G. Dt.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. F.

G.

G. Ot. F.

G. Ot. F.

G. Ot. F.

1100 F

1045 F

1210 F

920 F

902 F

7040 F

1100 F

1056 F

1869 F

1045 F

880 F

1320 F

770 F

990 F

500

700

490

640

550

390

500

600

500

600

640

600

550

600

12/ Klg

Klg

CzI Klg

QIKlg

QIKlg

Klg

Czl Klg

Klg

Q/Klg

Cz/Klg

QIKlg

QIKlg

CzI Klg

CzI Klg

Cz/Klg

CzI Klg

Jp

Jp

Klm?

Jp

Jp

Jp

Klm

Klrn

Jp

Jug

Jp

Jug

Klrn

Klrn

Jug

Klrn

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

13

(1635 )

(3180)

(4045)

(1545 )

(590)

(1365 )

(455)

(2730 )

(1635 )

(2455)

(2910)

(910)

(4090)

(1635 )

NSW Bores

4024

4032

4099

4121

4132

4163

4185

4611

4685

Boomi

Boronga No. 1

Careunga No. 1

Coubal

Dolge11y

Carcunga No. 2

Euraba

Wclbondongah

Boronga No. 2

177

198

201

174

194

195

191

182

1221

1322

1223

1216

1245

1223

1220

1138

1393

998

1157

1098

1213

1232

1016

1222

987

1295

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Ot. F.

G. Dt. Fe

G. Dt. F.

795

778

848

746

823

808

1012

757

819

825 F

792 F

836 F

770 F

814 F

792 F

902 F

792 F

825 F

450

400

450

410

430

450

530

400

420

3.48

2. 76

3.92

4.23

3.90

3.94

3.63

4.26

2.87

CzI Klg

CzI Klg

CzI Klg

CzI Klg

CzI Klg

CzI Klg

CzI Klg

Cz/Klg

CzI Klg

Jp

Jp

Jp

Jp

Jp

Jp

Jp

Jp

Jp

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

Flow

(3090

(2730)

(910)

(3090)

(1365 )

(4090)

(2385 )

(2865)

(3180)

Petrolewn Wells

U. K.A. KentuckyNo. 1 237

U.K.A. Mt DrivenNo. 1 205

x See text fur explanation

2146

1743

1105

1159

G. Dt.

G. Dt. F.

900

500

Klg

QIKlg

Jug

Jug

Flow (90)

Flow (2275)

-32 -

TABLE 17. WlIU:LrNE-LOCGEl', WATER-BORES AND CONVERTED PETROLHJM WELLS IN TilE

COOi\11 I \'tl NI) I 1: 250 000 SI/I:ET AHEA

Reg.0)o~ I'J i1/IJe Elevation

Cm)

Depthclri 11 ed

(m)

Depthlogged

Cm)

Logsavailable

G, :\ , Ut ,T, F, EX

AnalysedT.O.S.(ppm)

Conduct ­ivi y

( S/ cm)L,F

SalinityFieldsalinity(ppmNaCl)

IlCO;

Cl-(emp)

SpuddedIn

Deepestaquiferpresentlytapped

Water-level

m

(flows In3

m / day)

288

G. N. Ot.

G. N. Ot. E. -

G. Dt. F. 947

8

13

Flow (9)

Flow (9)

Flow

Flow

13

Pump

Flow (small)

Flow (2270)

Flow (36)

Flow (14)

Flow (23)

11

Cz/Klc Jug

Kly KIm

Cz/ Kly Jug

Cz/ Kly Klm

.Juo Jug

Kly Klm

Juo Jug

Kly Klm

Cz/Juo Jug

Cz/Juo Jug

Cz/Klm Klm

Cz Jug

Cz/Juo Jug

Cz/Klrn Jug

2.69

3.28

0.88

3.27

0.59

2.59

2.20850

600

1200

1100

840

1100

1200

750

800

1650 L

1700 L

1675 L

1950 L

1675 L

1175 L

1190 L851

1472

Ot.

G.

G. N. Ot.

G•N• Dt. 1206

G. Dt. 1469

G.N. 1264

G. T.

G. N. Dt.

G.N.Ot.

G.N. Ot. 1409

G.

943

300

250

285

216

302

265

176

297

596

278

252

315

373

320

309

305

307

616

340

301

357

366

341

341

960

299

11950 Wyaga No. 2

11743 Monte Cristo 232

11995 Aronui 257

12088 Farleigh No. 5

12158 Iona. No. ')

12631 Gillina No. 2

12639 Bent\\i'ood

12702 Wyaga No. 3

12714 Wyaga No. 4

13300 Springfield

2822 North Callandoon 209

8551 13illa-8i11a

10284 Yagaburne No. 3

11645 Euloma

1.3744 Murra CuI CuI

13909

15180

15465

15624

15663

15976

16039

16140

16275

16281

16354

16503

No. 2

Wondalli

Githawin NI,. f

Kildonnan No. 11

~Ie lness

Zilzie No. ')

Lapunyah

O.K. No. 2

Kulai

Zilzie No. 3

Undabri

Torridon No. 2

354

376

306

338

366

334

373

1006

648

338

369

682

305

293

377

206

262

374

326

372

975

643

.329

369

651

302

G. N. Ot.

G.N.Ot.

G. N. Ot.

G. N. Ot.

G. N. Ot.

G.:'J.Ot.

G.N. Ot.

G. Dt.

G. Ot.

G. Dt.

G. N. Ot.

G. Ot.

G.N.Ot.

1495

1085

1063

947

1092

1044

1686

1703

1129

1767

1122

1680 L

1325 L

1450 L

1240 L

1330 L

1260 L

1740 L

2030 L

1240 L

2070 L

1220 L

950

650

750

600

700

850

1300

1030

1000

900

1000

850

8.34

3.99

1.55

2.87

4.82

2.90

9.44

2.17

3.27

2.66

4.04

KId Klrn

Cz/Juo Jug

CzI Klrn Klrn

Klg Klc

KIm Jug

Cz/Juo Jug

Cz/Klm Jug

Klg KIrn

KId Jug

Cz/Kly Juo

Cz/Juo Jug

Cz/Juo Jp

Cz/Klm Jug

Flow (23)

Flow (90)

Flow (2.7)

91

Flow (68)

Flow (68)

Flow (90)

Flow (1135)

Flow (45)

Flow (45)

Flow (435)

Flow (45)

Flow (45)

TABLE J. 7 (contd)

-33-

Reg. Depth Depth Logs I\nulysec.1 Salinity Deepest Water-level~o. Name Elevation uri 11 cd logged available T.. V. s. Conduct - Field IICO;

Spudded aquifer m(m) (m) (m) G, N, Dt, (ppm) ivity salinity .in presently

T F EX ( 5/ cm) (ppm Cl (emp) tapped (flows 1.n, ,L,F NaCl) 3m/day)

17877 Merinda No. 2 299 367 177 G.N. Dt" Juo Jug Flow (4. 7)

22140 Arrowfield 482 408 G.N. Dt. 1246 1600 L 850 1. 54 Kly Juo 27

31127 Ninc.1alyup 273 197 G.N. Ut. Juo Jug 6

31293 181 G.N. Dt. Cz/Juo Jug 14

34768 310 312 G. N. Dt. 1139 1300 L 700 5.71 Cz/Klm Jug Flow (340)

34814 418 412 G. N. Dt. 1034 1300 L 700 5.38 Cz/Juo Jug Flow (68)

36075 352 210 G.N. Dt. Juo Jug 13

4578 Tulloona No. 2

(N.S. W• Bore) 208 1117 671 G. Dt. F. 834 1025 L 450 3.94 Cz/Klg Jp Flow (5000)

Petroleum Well

22181 U. K. A. Ting<U1

No. 1 208 1816 1004 G. Dt. F. 1000 Cz/Klg Jp

Flow (2045)

X See text for explanation

I

. ..,Roma

/ / // // ./

. .· .. . . . . . . . . . . . . . . . . .· " .· .· .· " ' .· . . . . .. . .

.' . . . . . .- ~ , . . . . . .· .. . . . , . . . . . . . . . .

· '. '.' .... .. ~ . .... . . . .. .....

· '. . .

· " ,., .

· . . . . . . . ..' , . , .

.' .: .< '. :: :".:.: :: .< :-> :.::.:-.:. ::'..'<.' .'. :.: :.: :.:::-: ::::'. ::.: :: '. '. .re m=-

.................................. : ... :....................... ....--..... ,

• •••••.•••••.•.••.•.••••• , 0 ~::::. >.::': ::: :.::':: :'::': >< :<:.'.:..-.:: ::.::: ~: <::.::! u•• " '0 H

::(/:••::·8·.:((/(>::>/.? i::>.-.:...::>.. ~ .. >.<...>..>:~>.:: ..»:::: n !

·.···.·.·.·.·.·.0·.·.·.·.·.·.·""""'.·.·.·:.·.·.0 tl.·.·.·.·.·.·.· .. ·.·.·.·.·.·.fn.·.·.··.·· tt ~

::'.:'.:: :::'.: :.': .'.0.:: :.': .'::: .;;;::: ::::: :'.:.: :::.: Cl=1 = ~~ Pl - ~:: :.:.:::: :: :: :.<:::.':::;:r, :::: >,:'.:: '.:~ AREA /::.'..::::.::.::.::.:..:.:::::::..::.::.::.~::~.~.~ ..~~MULLA COVEREO....................... ',' 0'···· ···SHELF . "

i(j:i\;::l\:\:i.;~~ \::\(!~:\::.:;QJ}i: : "·<:.·····:··"7~CENTRAL· WEST·'·

· . /' . .- .. !..... .· . . , . .' . '. . . . ~ . ,

........................ FOLDED·· . . . ... . . '" .

.......................... BELT'·· , .' . . . . . ..~ . . . . . .

'----..L L-----..l.--'--__....I.o...--._~_~_-L.- ---J

(" • • Ir ,-1

!. ..if_ .• ' ,. j

Surat Basin Limit of Great Artesian

Basin sediment

r: ':. :,:.]1., .!' .:L~:·.,

Other J uro ssi c - Creta c eousbasins Fault

. ,' __4 __ ._.\__...;_J

Permo - Triassic basins--000 Basement ridge

oI

100I

200I

300 kmI

Fig. 1. Regional geologica I setti ng.

<1>Cl.

;"<.o

Q.

lOOI I 1111500 1000

I 11 I I5')00 i(J (lOO :)0 000 I()() (JuO

Con:1ucllvily of aqueous s,;lutions of Noel ut variOuslerr,r.,,:'rIJtures (n(jopteil "')rJ' tlq j 10 In [)nvI') B de Wle~;tJ rCJf,(,)

AUSI/328

WEST OF 149 0

jOOO<lJ-0

Q.l C C CD 0 0 0- C .0 C0 0 -_. E u Ec 0 cD 0U D U

121/109

• Hooroy Sondstone+ Moogo Sandstone

x Cubberomunda Sandstone

v Spr Ingbok Sondstone

Hutlon Sandstone

:J 6 7

HCOi/ Cl-ratio

..o

+

..

Assumed mOJor ~C. fer

(= lowest Gyu,fer lapped)

43

....+.. .. x •

x

2

+

x..

.. +o

..

EQ.Q.

(f) 2000"'0

0 ..(f)

"'0(1)

>0 ..(f)

1000(f)

"'0

0

J0~

0

300D

EAST OF 149 0

Assumed mOJor aquifer {+ Moogo Sandstone

x GubDeromunda Sandstone

A PII i I go Sandstone

+x+ + + ++ +

+ x+ A + + + + 17· 6-x

++ + + +x + +x +

+

x x xxA X X

xxx A

A'X AAA A

EQ.Q.

C./l 2000"'0

0C./l

"'0(1)

>0C./lC./l 100J

"'0

0

0~

00

+x

xx x

2 3 4 5 6 7

H C0 3-/ C1- rat i 0

8 9 10 " /2

Fig.3 Graphical f..'resentation of 'Sater -.hemistryRecord 1974/113 AUS 1/329

x x xx

x

x

x

*x

x x

xxx

oo 0 0

xx

x

o

x

o 0

HO'JroyS:jlHjsl0ne

Jkh

MoogoSondstcne

Ki::,

D\JubberomundaQl

0.. Sandstone " 0.. ..

Cl.. Cl

~ Jug x~

x x x

>-..-CQJUlQJ P,ll'gae-

O. :~;(J n(j s! une .. ..0 • • • • • 0 0 .. o Cl 00 "Jp

e- XQJ..-:J0-

<1

Ul Hut tonQJet S.JndstoneQ'cv Jlh )( x

0

Pr~(lplce

SuneJstnne.lIp

••o o

x West of 1490

o East of 1490

..x x x

1000 2000 3000

Supply (m3 / day)

4000 5000 6000

Fig 4. Estimated flow rates of flOWing bores drawing from various aquifers.

Recure! !CF<I/ 11.2) AUS 1/330

Pre -JUroSSIC 'ocks

[ __~ jfl,fOiL)r aqu l, ; er" names and descriptIOns In Table /

East

cro~~s -serf"".IOn QC ross the Surat BaSlrl to ch_ ow m aJor aQ:Jifers.

27°

28°

[;l

Dalby

-r--1')1"

,/,/

,/,/

,/,/

"""".d'Chinchilla,/

Millmerran\. C

. ~ -U .

. ~ p..~ rn C

.':::0 GJ ..... ).:t:>

. ,. ' .. \

o GoondlWlndl',' J. ,,',

ISO"

east+IIII

I

I

wesr

//

s t cfeorge

/

liJMorvel1

148 0

,--------------r---.14., 0

29° L-__-L_J.. I£.- '-- • ...J-.ll..J....I..L-.~_'__ __'___=___L_ __1. J 290

147 0 149" 150°

Areas In which named aquifers ore shallowest major sources of ,·Ialer.

Hooray - Mooga :-,;. :. 'ortes

Gubberamunda - Pilhga ~:"J:;tones- 200 - Depth below t;]round of Hooray - Moogo aquifer (metres)

r I I Edge of Surat BOSln

.. '. Hutton SI]!) lslone

Marburg ::: ]·.Jslone

• • .' Precipice (".,Ycstone... ..Flowing bores are generally baSlnward of this line

Fault

F',g 6. Dlsfnblilion ;f aquifers."

Record 1974//13 AUS 1/332

Plate I147°00'24°30' ...---------------- -----

SPRINGSURE

148°30' 150000'----I------------~~~M~---------r------------------------IMC)Ni=O-----------__-------------- ~151030'

BARAlABA MONTO 24030'

....... -.,-.. .._ ..... ;.... ~1, r'.• , .•

OALBYo

o

CECIL PLAINSo

.\,l,-..... TEXAS

,0..........

""

INGLEWOODo

13471C(

CHINCHilLAo

,,16400.-

t l2158

t1650~

//

/1

//

11743 608551

.t. 16275o

(, Tlngon

12639 6 t 11645u

/6234 t

MOC 1 11492 MILES"no 15670, +'( ?

Dogwood'

....

"(1055~0"­

"-'11306 \c) /6686

14598 (S \t \

6~3882

//~'3/80

,/

// 'f16065

,?15487

OBurungQ 510809 1i t

034227l'

016039

~15465

~ 4578

,j 4099

15728~• 6

016589 15171ONew 80re

12814 If 0"739+~1I43i

64185

4163 0

MEANDARRA15036()nl'Palorna ~

016654

64611

014?04 _--_t /' --....

~ 12236 1630788 ......, I

914388 () /4190

91'\680 t /7070 t,01l50! \ 33283() TAROOM .t {)35458 0 14609n

t \ (',32735 +30535(' 16607 f

t er \III

16000 16225

?W/

//

'? 15525

<f 14861

0"410

14121v

04028

CAllon W

oKentucky

Cf59

02973

Scale I; I GOO 000

6 4045

64043

INJUNEo

0'3820

o2414

64918

DIRRANBANDIo

0 4921

64920

t 97

016735

63475

r 2770

63476

?2976

6"85715523

?,?2975

0149(;40 039

Cf4185

11354

'?

0"954

014826

1483

02883

'? 4587

613586

?4999 015183

1603

?

1599

11287 '(1601?

'?Cf4687

?1600

12106 C(4585 CflboJO ,?1610Cf

62884

388~DMORVEN

17"13

25°00' I-E-D-D-Y-S-TO-N-E----------------------------T------t;:TA~R~O~O~M~-------------_r"..~-------'-----:----~=:-----~M;UUJiN\iiDDiu::ii8:jj8:jjEr:;·R~A1----:-------------:--------___:_-___:_---:-__----------1250

00'

26°00' I-M-IT-C-H-E-L-L--------------?-;:ION

9;Q8A4--------------------T;R::O::M:7A:----------------------------1-:'- ---------;C(~1ii515i&60olt"trCH;:mINj(C;:Hmll:-jL--:A;:----------~~~-,,L----- ---__-.I- ~ 2600~'

1 \/ WANDOAN I

/ 104790['),

/ I1 I

/ /1 /

/ I1 I

/ //1 I

387 MITCHElL / IW--_ / I/613951 -....... 92623 / II ............ 303) ROMA ARO 19/

I '.2622 0285

lO 4257 Lotemore E '( / ,I"+0,9" 0 'I 6 ,,~ 0 3851 tt, 3852 t ? /

I "- t / 0/5696 \14027

62621"- 17236 14930 b166S, \ ?

\ \\ ~850 ~2339 If> --om9/"- -. _ :'-\(~66(.;' \

I \ // 1381~O \

I '" ~,/ 131550 olaoo \ ()121361604/ ...... './ f

If / -- - --- '012421 014810 616235 0'16264614307 -. -" /2188 913518

/ 16204 ~~013936 t 10841 , t /4851\1 0 616174 0 ~. 0 \ ()"701

/ 611754

015302 13248-' \ f

r::..:::....=------------------::-.".:./:..----·------------i;;:;;-;:;:-------:-::----------------------t-----~ii495-~~;;_-\---------------- 3137127°00' t- -. __ _ __./ SURAT 010 '. 11495 DALBY '?----- ~ 27000'

HOMEBOIN ------------- 0 3477 0"740 61629

t l3455 \

t 1105/ c\h682 \ r,Cobbor.eno68654

0 t62 \ ~2762 0, 0 SURAT t. 7ey

~ 0 ?405~ 13809;) l.: \

0'5101 \4052 0 4051 12569 t .!,OO'''d.'on? t Gl ENMORGAN ut 14906 O· c; Bennet! 2

O . •~'?'53,7/10 ';: t 1142/n' " \

1152 j n '''t 13030 ,tp565. 012/90 () 14141of ":2 .. .. - Cl ':i i' +

121:> 33 0 0 • 13138/7385 /3140 hl2278

11555~, ~ /6445. ~,\ )?

t,/2447 14742616550'- ; 'ii79":';

1III '(17689

I 15124 ()18083Moonie NO I \( ~.

• 10 MOONIE352516 / ttRet,eol

31860 t c; 30316'() .'30346 )16984o . (9~ockerll/ +

)"/0.1""1.11::1

/'+ '(C'owde, E

17435· I? Cunojong0,Widgewo

'- '? GOONDIWINDI"- 120886'- 22140? _ _ _ /7877

16140 -.?- - <!\ i2714613744 3112710 ?

t 10284 t'-' 11950 ?31293

\ ? 03607515180

6t

\ 0/27021652'; 0 \ ~

\\\

61'6354

• 34768 ,Io 12631 CJ615663

34814 • I 11995

GOONDIWINDI 15976 t. C 013999\ <+',-q u 016281\

,./--_/ .. 615624 \

- \ ./ t 13300 I, () I" '-'"-- ''-,-f' "1 "-

//

"

t 24

1- -~:_:_:_~-----------~O~---------_t__::_;:;;;_:~::_==-------6MI Driven28°od BOllON t 397 ST GEORGE

DIRRANBANDI 0 055 00 014712

t 26B6 t 147 ST GEORGE 6 to 03820 0 4399 04401

616783

29°00' L----------------------~J-----------1::4:80:0:0-;-,----------L....I.-------------------------;15;;;0~0~0::;;0'--------_-.1. --------------L .-J 29000

147°00 151030'

O/A/609

oI

20I

40I

601

80 KILOMETRESI

016735Wireline-Iogqed waler-bore wilh reqislered nl/mber Edge o( Swot BOf;,'in

Crowd", E . , , Io Wlrelme-Iogqed petrolel/m exploration we I converted 10

water-boreo Bore, flowinq when logged

? Bore, nan-(Iowlnq When logged

Appro.oinale outer limit of (,1owing bores

Slate boundory

Index 10 1:250000 Sheel areas

o Townsttip

Plate Wireline-Iogged water-bores in Northern Surat Basin

'S'~O~T. V I \ r'""" •

150 0 00'--------'-.~

Mou1ao,d

128°00'i

OMundubbera

~'

oManta

+

+

P

I

,~.-----:-::-:-::!:-I--:--------t90 00151°00' 151 0 30'

OCrocow

+ OT",,,,,,,

Jil026

Ji 1046

106S

p I125 1276P;C/163.0 o~302 . 1291

.0'1112 1219Ji P 1~76\. .o"285.d~1153p 1310~

Jill14 f1

117;-.0'1186

p'1165

••

•

oTal .... aod1270p

•

.0'1180

•

+

•

p'1052

p946 948 "1040p

Ji978 o'107~I087

p-i023 ~126 '/PIOOI I d l098

1I06pV pl1461195

•

P'

P

•

•

d

P

Munqlndlp _------·----------1-4~9°00'

+

/48°00'

• • II~O)

cP .0 1037• '<J ••

! pi030

••

•

•

•

•

•

•

•

•

•

•

143

28°00'

29- 00' L---,- ~_-'----L...J

147°00'

Scale I: 1000000Q/A506

20 10 o 20 40 60 80 100KILOMETRES

Contour interval lOO m

Fault

Outcrop of Wolloon Coal Iv/easures

Petroleum exploration well

Wireline logged water bore•

r

60 MILES40, iI I'

20i

o10

Limit of Wal loon Coal Measures (=Birkhead Formation)

Outcrop top of Walloon Coal Measures

I I I I I I I I I ti

Plate 2 Structure contours, top of Walloon Coal Measures

PL

AT

E4

I-I-

--f-

~.

I..~

~IJ

fI'I

...~I.J

~I

\I

I

HS

TR

AT

IGR

AP

HY

~,

rr-r--r-r"""T1~.-r-~-r-T"-r+.,...,-rH-,--r-T~-r-r-r-rW--rA-rL...,..L....O..--O-:-Nr-r-r-r-r,-,-C.,-O.,.....Ar1Lr;--r"-----r-r-r-M.-E,...,A--rS--rU.,...R-rE.,-8,.,..-,r-r-r-r-r..--r--r--r->~....,.--y--r+-E.,.....,Ur--lRr--r0-rM.,..BA,...H.,..-,-F--,O..-"R.....,.M-,-A........l'.'_O~N~-,-,..-,.-IL-,-~,....,-,--r-:-~..,..-~--,~-rH

-,-U...,-T.,-T_ONS

AN

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/611

Q/II/612

Orallo Formation

Gubberamunda Sandstone

Mooga Sandstone

Bungil Formafion

Doncaster Member

Litl1ological correlation

Alternative wireline-Iog correlation

100 API units for Binya No I

---_.....•._-------------

Depths on logs are in feet

~---)l)\ 100 API units for water-bores

Walloon Coal Measures

k

C= casi ng shoe

BORE16140

CORRELATION OF GAMMA-RAYLOGGED WATER-BORESBETWEEN ROMA AND MOONIE AREAS

Griman Creek Formation

2070

MOONIE AREA

Coreena Member

Surat Siltstone

kC--100~o

355

PLATE 5

1155

'-------,---------------

Pilliga Sandstone

1020

""""",""-

"""""-"-

"-

""

Dalby

•

,----------------------

1------------------..-------------'---

Contours on the top cf the

Moogo Sandstone (metresbelow seo level)

/

2620

BORE127

1390

900

--+200-­III Ra:no

lrL.----,-5~-OJ

SI. George •

km 100

,~----,-_.o;!-;I~ ,-L~LL--=--=--=--=--=--=--=--=-L=-----J--...J148" 1490 150" /1'",1° 290

BORE15523

1170

3705

500

2225-

2920-

1570

3370

3080

_---J_-- 'J

~

Cainozoicsediments

BORE62

~--IOO -)I

o75

1190---

BORE3850

!E--IOO -71o

370

1320

100

AAOBINYA

NO 1

1

485

1270

I­t

, 3905 {'

jc;

. {

·::6~ {

Orallo Formation

Mooga Sandstone

ROMA AREA

Bungil Formation

Coreena Member

Doncasfer Member

Evergreen Formation

Hutfon Sandstone

=-Pr~clplceS-andstone

Palaeozoic basement

o

100

146011

j~ f"'",,~]~"t ~1 1835 C

12110.?" ~~c

Gubberamunda Sandsfonp. £ L___________~2=.=2~6~O300 _I 2270

200

100

Walloon Coal Measures

3490

200

Westbourne Formation

Springbok Sandstone

2730

2540

400

700 -

700

600-

300

800

800- __

500

400

500

900

600

Metres900

SPRINGSURE 100 kmROLLESTON fI km !ill km BILOELA. 13 km

PLATE B

I

" (Gltnlrdtn I

JJ Glenou 1

1 :"if.. 0-:~. Bh>lHllh 111 ". .K·.~·~ JJBm4lfoo1 ttat~·~···

... ' LAMEN \ ~Ir,~ ;'Traffof4 Par. 1 {1 p WAllUM8Il~~

Sr. Mtl11 \ '.

\COO,..fdOO 1 ~1Iy WI~1 \. )

·,;.,-r·,··..jOONy CREEK '\pB.rdlomr",

ARO J,:J

Water bore

p{rtl~

~~GLf. 2. Ir

fl." .,~~~..:..P1:,SA.Trlll,,,....",,,(l- [1. . P -00: ~MIMOlI.I

: ..... b ~: I) p -0 : J1~~rr1

:" 1!;;j' .. .11') """,,JiI .: S.....y~·

Oulbll t' er 1 '.f1~.... ". PINE RID~ Wy.lII\ ~J JJ MI"'",lon 1 . ".B01~RB02 :' ~ .••••;i1f••••••

AA02 •... 0'. : f....-.Q:~, \4 JiI RBO 3 WmSlon' '. : :JZ'~.; RASIJE p's.w,rl 0( 1

)".. Rl ~RO·;1·J!..p.: .... ,l!-r1JJ ...~..YANALAH Blytlllult .• '

: pH1.' .

@ nM8Um:,~.Jl.lS (J~~AAO "'RD S

• ARO 411 latttnort 1

o

3 Stratigraphic drill hole

Railwa'(

,:J Abandoned well with show of oi/tmd gas

o G8S well

Scale 1 1 000000

Published by the .Bureau of Mineral Resources, Geology and Geophysics,D~J».artm8nt Of. Minerals and Energy. Issued under the authority of theMlnll~ter f~r MI~erals and Energy. Base map compiled by BMR from 1: 250,000PlanimetriC Series of the Division of National Mapping, Department of Mineralsandl Energy and the Royal Australian Survey CorpsCro.wn Copyright ReservedPrimted by: Mercury-Walch Ply Ltd., Hobart, Australia

Town

• Oil and gu well

BlylllWD~·

tI.tIlI :::jj(;1·...MAFFR

J1 : 'it' d GIeIll:Otfif ' .......'HoIlvrrootll

Clfftla 1 JJ jQi-.ANA8RANCH '..~;i;

Limit of group of wells with SlJme name

• _ • State boundary

• Oil well

-24 Water bore, gamma-ray logged: with IW$ registered numberin Queensland. wC!e registered number in NSW

f6- Abandoned well with show of gas

J1 Abandoned well with show of oil

Lambert Conformal Conic Projection

JJ Abtmdoned dry well

Highway

~ Abandoned ges well

r' - - -... Oil field--_/(CJ Gufield

-li Gu condensate well

300 Topographic contour in metres

Road

ARO 12 ,:JMrRkllP

148,~40~'rr:;;;;;;-;;:-_E_N_LA_R_G_E_M_E,NiiiTm"R_O----;;M,A-P-E-T-R-O_L_E'U-M-F-IE_L_D_S ~,~49 \5'26 IS· I SMHL I 26 15·

27 00' '::::- :-__.::..__-::,- -l.::JL /L--l ~ 27 00·

148 40·0, __.....JL-__'.L0__.....J__---'20 KILOMETRES 149 15·

2OL..__~'!LO__....10 ~20L- ~40L- ~"''--- ~''''-- .::1~ KILOMETRES

PETROLEUM EXPLORATION WELLS ANDWIRELlNE LOGGED WATER BORES IN THENORTHERN PART OF THE SURAT BASIN

--

25~ 00'

00'

28 00'

ooo

.!•

I

~/

V

GLEN INNES 110 kmWARIAlDA 10 kmMOREEllOkmCOLLARENE8RI95 km

o117!l4

,f

o

o

f~

--b_A"",,--JI\\~

J5473

oo 000

o

'"o 0o 0

o

..."27/0·

o

o

o

'49

o8MR~

2916 ~

3476

J

3819

o

297!1

\ ,

V

BREWARRINA 1$0 km LIGHTNING RIOGE Il5 km

1609 j,

(p-

I

\\

4')8')

o

II

J1 HAM Whl"flb,a 1

'./1!'""""o

16416-

119'34

;. ))

o

)

\

\

)y

/,

o

o

o

II

I

I

13')86 ~

• 011287

4681 ~

o

o

o

o

o

) \\

I dj,.J I /

( '.R~i'.( I

o

o

X\

o-2686

oI

o

o

o

o

o

o

oo

o

• 168

\

\

173'0

27 00'

26° 00'

25" 00'

SPRINGSURE 100 kmROLLESTON fI km !ill km BILOELA. 13 km

PLATE B

I

" (Gltnlrdtn I

JJ Glenou 1

1 :"if.. 0-:~. Bh>lHllh 111 ". .K·.~·~ JJBm4lfoo1 ttat~·~···

... ' LAMEN \ ~Ir,~ ;'Traffof4 Par. 1 {1 p WAllUM8Il~~

Sr. Mtl11 \ '.

\COO,..fdOO 1 ~1Iy WI~1 \. )

·,;.,-r·,··..jOONy CREEK '\pB.rdlomr",

ARO J,:J

Water bore

p{rtl~

~~GLf. 2. Ir

fl." .,~~~..:..P1:,SA.Trlll,,,....",,,(l- [1. . P -00: ~MIMOlI.I

: ..... b ~: I) p -0 : J1~~rr1

:" 1!;;j' .. .11') """,,JiI .: S.....y~·

Oulbll t' er 1 '.f1~.... ". PINE RID~ Wy.lII\ ~J JJ MI"'",lon 1 . ".B01~RB02 :' ~ .••••;i1f••••••

AA02 •... 0'. : f....-.Q:~, \4 JiI RBO 3 WmSlon' '. : :JZ'~.; RASIJE p's.w,rl 0( 1

)".. Rl ~RO·;1·J!..p.: .... ,l!-r1JJ ...~..YANALAH Blytlllult .• '

: pH1.' .

@ nM8Um:,~.Jl.lS (J~~AAO "'RD S

• ARO 411 latttnort 1

o

3 Stratigraphic drill hole

Railwa'(

,:J Abandoned well with show of oi/tmd gas

o G8S well

Scale 1 1 000000

Published by the .Bureau of Mineral Resources, Geology and Geophysics,D~J».artm8nt Of. Minerals and Energy. Issued under the authority of theMlnll~ter f~r MI~erals and Energy. Base map compiled by BMR from 1: 250,000PlanimetriC Series of the Division of National Mapping, Department of Mineralsandl Energy and the Royal Australian Survey CorpsCro.wn Copyright ReservedPrimted by: Mercury-Walch Ply Ltd., Hobart, Australia

Town

• Oil and gu well

BlylllWD~·

tI.tIlI :::jj(;1·...MAFFR

J1 : 'it' d GIeIll:Otfif ' .......'HoIlvrrootll

Clfftla 1 JJ jQi-.ANA8RANCH '..~;i;

Limit of group of wells with SlJme name

• _ • State boundary

• Oil well

-24 Water bore, gamma-ray logged: with IW$ registered numberin Queensland. wC!e registered number in NSW

f6- Abandoned well with show of gas

J1 Abandoned well with show of oil

Lambert Conformal Conic Projection

JJ Abtmdoned dry well

Highway

~ Abandoned ges well

r' - - -... Oil field--_/(CJ Gufield

-li Gu condensate well

300 Topographic contour in metres

Road

ARO 12 ,:JMrRkllP

148,~40~'rr:;;;;;;-;;:-_E_N_LA_R_G_E_M_E,NiiiTm"R_O----;;M,A-P-E-T-R-O_L_E'U-M-F-IE_L_D_S ~,~49 \5'26 IS· I SMHL I 26 15·

27 00' '::::- :-__.::..__-::,- -l.::JL /L--l ~ 27 00·

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2OL..__~'!LO__....10 ~20L- ~40L- ~"''--- ~''''-- .::1~ KILOMETRES

PETROLEUM EXPLORATION WELLS ANDWIRELlNE LOGGED WATER BORES IN THENORTHERN PART OF THE SURAT BASIN

--

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28 00'

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GLEN INNES 110 kmWARIAlDA 10 kmMOREEllOkmCOLLARENE8RI95 km

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PETROLEUM EXPLORATION WELLS AND WIRELlNE LOGGED WATER BORES USED AS DATA POINTS PLATE

147;0~0':;;:;;;-:;:;::;-;;:;; II -:-::=~:- :-:: --~14~B~·fs,~0·\RAL:Ai3A-----------r-------------------------------�~'~ol·~o~o~·lNTc)-------------------------------- ...::~240~ 1~lg30'

SPRINGSURE ( ) BARALABA MONTO 24·'0'AOE3 Consuelo rlJo.' (J AFO Rol1uton I

P AFO Pur brook

.s ~doJtrlllfl

(tl6)i.'.,~S

olEP Jondowo. S

olEP Jondowo. W

pTEP Stockyord Creek

t:fAPN Abereoro

(1 APN Bukol

JiCOL Sp'culotion

CHINCHILLAo

Cre.k

OCRACOW

JilKA Picurdo

PUKA Mockie

MILES,0' UTA Com.by

IJUKA Cockatoo Cr••k

UKA Dogwood

UKA Binky

']j~ ,O'UKA Bullock.~KATinHuf

UKA GurulmundlKACooloi

16204

o 00"24B CONDAMINE

UKA Weril'l9o.crWANDOAN

o

!f 'JJ UKA Auburn

UK' 0",= ~UKA Paddy CrUkp14027

o

TAROOM

~3Z735

UKA Wondoo"..cr

14307o

,O'UTE Woleebee

UKA Giligulgul,O'

UKA F.rre''p

UTE Glenouby";:r

696

016264

....cUTP Amoole.J'*' 16174

o 015302

014861

JfAAO Jenoyole

{JAAO Kooringo

J:fAO Rosewood

_AAO Kalimo

013038

.o'0SL 2 (Hullon Creek)

J:j A FO Purbrook S

INJUNEo

t:lEC Worrinllla NI

SOD Morello

AROf

2B'o

LAAO Mt Beagle~RO la P ;fAO Nlell0

\

pAAO GlenollonAAO We'tlond'p, AAO Pt Hll1'rl' ~

)-' --<AAO Dolmulr Jo-'EOC MuggletonAAa Slee£] Creekp )-J

AAO aUlbetY.\AAa Pine RldQ'! ;lAO Fgl'lie

AAO Hodg'l/' AAO T~en ~AO '(00010;;0' P AAO Sowpit Creek

ROM'A AAO Wotlonooko,p po AAO Beaufort pAAO PickonJinnlO

APJJ COOliboh{fAAtJ}rle \ fJAAO Slyln CreekAAO Bonnollen --< . ....AAO R1chmondr<AAO Trofford Pork

AAO Arbrooth.cr tJ >-'AAO Dirmdo P \ '" Prl .AAO Binyo AAa Blythewood AAO Bengollo

AAa lofne'"" .....- P AAO Bordloming,-3850 u 2339 ;J, - ~~AAO 80ny Creek

AAO Volley Downp: AAa Moffro j.1~o"PAPNWollobello

AAO Hotlyrood rf P 1~155 0 ----.0 2340 AAa Lyndon COlle"- APN Snoke Crpk AAa Lorelle

pAPN Bolgownie W 12"'21 P 016235I p AAa ComborngoAAO Bruc.dole.-: p.

p AAa Boondoro 108"'1

APN Ob.rino AAO SUnnybonP 0

AAO Glentulloch Ip

AAQ Kildare la

AAO BindonQap

2622o

AAQ We"orav, l.er

AAQ WeslQrove 3.0

AOE I (R.ids Dome)p

A/JI) KilloronfJ

AOP SttotnmOrll

~.AAO GI.nroy

MITCHELLo013951

pADP Donnybrook

1604o

tJ PEC Warron;

AAO Womblebonk JJ

PEC Crystal brook fJ

PEC Tooloombillo s:J

01603

01605

04185

4585

.. ADP Scolby

11354o

pUPR MUl19ollolo I

pAOP Dulbydillo

04687

MORVEN

Q,'2741

1773

ARO 9 (Gunnewin)p1--c::-c-::C'C-----------------;::-;o;iB<i------------------------i;;;:;;:;-;:: :;;;;;;;;-+;:;:;:;_UKA Buruooo I

26°00' t ~MITCHELL 0 ,09B4 ROM A 0'''60 CHINCHILLA

AOP AlbO.... , ,

AOP TreQale

Orion MarYllol.pOrion LowOOdp

MILLMERRANo

,O'PSO Millm.rran

fJPSO Tipton

p'PSO Yorrolo

10 {DolbytfAL8Y

;/'SO llg log

INGLEWOODo

pPSOWOglJObo

pPSO Tinker Cr..k

PSO Wllkl'p

Ppsa Stohon ereek

,O'PSO Kogons S

~SOKogon

JJ1UKA Bro.mar

p-WKA Uronilla

016354

12639 0 0 11645

J1UKA Tingon

347682822 0 0 156063o WPA Commoron,O' 34814

GOONDlWINDI 0 0'399'

./...~ f1WPA MoogolOn/----./ ...

\ QUEENSLANDP ,

UKA Goondiwindi ""- ... _-........_ ,-,---",,' -..... .. "'-

NEW SOUTH WALES

U A Minimo,.

UKA Booberonnop

,-',(

.. .." UKA Mottnlyre..- ',_r-- , ... .....-, 0 4032

o468~

04028

fiJKA Dolk.itn

0134

UKA Yorrondine,O'

133 590o

0132

PUTP Mourochon

0 4044

p-UTG Tolov.ro

UKA Goulomol'}j UKA Trol"p

127 UKA Moomboh• P

04045

04043

UKA Kotootop'

013820

J-lKA Moron

o2414

0.9

04042

04918

DIRRANBANDIo

016788

04921

2770 J)OA Neobul Creeko P """ 1100A Hooloh Creek

~OOA Nooglllo

OZ976

016831

0149

03476

016735

03819

0'00

11 NAM wnYlnbirro

01482

o1483

01485

013586

0169

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.. ) Euo KinnimJf 04611

... "

l ~OL':6i7:.:' -:::;::;:- -L--L tl 4_'6_'_0=----::0~4_0_9_9;;;;;;;;;:-----------------------L--------------- l' _29°00' 148000' / 150000' 29°00

147°00 l 151°30'

;esso Gil Gil,,,

..-AOP Boheno,

/_ADP Borodlne Wesl

• e;~"~:dY Comp

1 -=::"""~---------------------7L--t;:;;;:;_;::;--_------------.:""",,---------------------- "-i4!;,--r;;:;-;:;;:;- -+,{Ul!K>.!!.uMllJilill•..• o,'__"_7_' -1,,·od ~ SURAT 01149> DALRY P

HOMEBOIN 3477 UKA Kif'lCOftlp UTG '(ombUQlej1 011740 llKA CooIOOtnQI}t1UKA Conclomine05 0 UKA80inbillf ..UKA Myoll Cr"k 0 16029 UKACobboreeno UKA cf. . UKAWomboCreek

08654 011 I \ 013682 a Wieamblllo r:f

62 UKA COIgoonrr . I f:J• Jo-' SURAT 40~3 UKA Rog.raP' ...AIKATey UKA Lowson

DOA H I h 0 0 138090 j..r I11866 11954 3475 {J 000 015101 UKA D"d OUTA Myro

o 0 0 04052 04051 UTE M.ondorro 12569 rr 0111 ,on

\

GLENMORGAN J:1 0 ~ • UK' U""II,o '7!l1' J:1 Io 1303~KA L.ichnordt TARA((314J41

UIN Redcop MEANDARRA 0 j 13160 0 0 12190t1 ,..UKA W.rlboo. 1503600 13139

/

P 173L8~ llM6 ;JJKA Toro ff d SO Kumborillo EUTE Polomo 016654 0 .JJKAToraS UKARoek Creek

UINEcho~ll, 0 Pt1 ~ UKA Lynrock OJ24"'7 14742 J:fKA Mo..moduo rlPSO Kumborillo

.__--"7:;;:-;;::::::::; 01655

/ 0/7986

..LJKA Pogo, '"0

11410 •• rl"_-- ~KA Glen.orn UKA CObowin..._f:J - ;.JUK A Pi.bold

UKA Bolonn.... p-UKA Dongo \ UKA Cabowin E.JJKA Kinkobillo dJKA Toombillo E PSO Durobillo C~IL PLAINS

UKA Worroo rfUKA Moullit jfKA Bog;o Creek P ,O'UKA . PSO Ounmor. Creek .... a 0- PSO eec,1 PlainsP '" I P'UKA Bidgel . Toomblllo rr PSO c.eil Plain. W P APN Horron.

ure BoxIei9h UKA Brigolow CrHk p-UKA Lldd~+~89 ..... PSOOurobillo WUKA Elgin ff UKA Tortt\Otf \ ,0' 0 r:f PSO Cecil Plains S

a .Cl ....UKA Coomritn UKA Hoyes Creek....c ;JJKA Middl. Ct"~083UKA Wongonul ,.UKA Wung.r ~ UKA Moonie N 0

UKA Yooroogo JJUIB Mamoree \ 0 15124 JfUKA MuodogoiUK' S"'''wood >f Cl MOONIE

UKA MOOnie~52510 p-UKA Rlitr'ol

{1 31860 030316UKA Su'sex Downs J 031860 016984

UTA AlIonN UKA Killoloep' UKA DoclIerilt

;:rUKA Kooroo" J6234 0 I a J1. p UKA W.ir

UTG F,',.ol' JJK' Flinton UKA c..owclerD' rl UKA BooroondoorJ p - UKA Curro' • gf1 Jo-'UKA Crowder E

UKA Alt n W • UKA Alton 17435o tJ I ;::fUKA Alton E .P'UKA Worrigobbie

1 c7iT,,'Wi ~02::2_4 ~/1~.~U~K~.~S~t~G~o~.,;;o~;;;;;;_-----'U~K~.~M!C'~Dt~;'~O,__;;;;""7.fJ~U~K~.;::'.~I~to~'i"='~IO'--------------------t_---_-+__~ldlJewo28°od ~ 80LLON 397 ST GEORGE 'ff UKA Kenlucky,O' OJ6039 GOONDIWINDI

DIRRAN8ANDI 0 0~5 0{] ;1UKA re.lbo WPA Billo Bilta.O" 12088ST GtORGE 0 4399 02973 I ~ 22140 0 !JKA Yorrill Creek

OZ686 0 3820 0 147 04401 ,I1UKA Ulo Ulo 161400 P 12714

!fUKA Worrie 013744 0JJ73 10284

rlBridg. Nmgnom 11743 0 11950Jo-' 11 UKA Tolwood 0 B'" 0

pUKA Geroldo 0 a.".

WPA Nomby' .WPA Thompson"f:f fj 16~a.qO

o 20

SCALE

40

1:1000000

60

pUKATey Petroleum exploration well .'----. Line of correlation diagroms

... UKA Binky Petroleum e~ploration well usedfor correlation diagrams

Edge of Surat Basin

Wireline logged water borewith registered number

State boundary

Wire/ine logged water bore with registerednumber used for correlation diagrams

1ST GEORGE Index to / 250000 sheet areas

PETROLEUM EXPLORATION WELLS AND WIRELlNE LOGGED WATER BORES USED AS DATA POINTS PLATE

147;0~0':;;:;;;-:;:;::;-;;:;; II -:-::=~:- :-:: --~14~B~·fs,~0·\RAL:Ai3A-----------r-------------------------------�~'~ol·~o~o~·lNTc)-------------------------------- ...::~240~ 1~lg30'

SPRINGSURE ( ) BARALABA MONTO 24·'0'AOE3 Consuelo rlJo.' (J AFO Rol1uton I

P AFO Pur brook

.s ~doJtrlllfl

(tl6)i.'.,~S

olEP Jondowo. S

olEP Jondowo. W

pTEP Stockyord Creek

t:fAPN Abereoro

(1 APN Bukol

JiCOL Sp'culotion

CHINCHILLAo

Cre.k

OCRACOW

JilKA Picurdo

PUKA Mockie

MILES,0' UTA Com.by

IJUKA Cockatoo Cr••k

UKA Dogwood

UKA Binky

']j~ ,O'UKA Bullock.~KATinHuf

UKA GurulmundlKACooloi

16204

o 00"24B CONDAMINE

UKA Weril'l9o.crWANDOAN

o

!f 'JJ UKA Auburn

UK' 0",= ~UKA Paddy CrUkp14027

o

TAROOM

~3Z735

UKA Wondoo"..cr

14307o

,O'UTE Woleebee

UKA Giligulgul,O'

UKA F.rre''p

UTE Glenouby";:r

696

016264

....cUTP Amoole.J'*' 16174

o 015302

014861

JfAAO Jenoyole

{JAAO Kooringo

J:fAO Rosewood

_AAO Kalimo

013038

.o'0SL 2 (Hullon Creek)

J:j A FO Purbrook S

INJUNEo

t:lEC Worrinllla NI

SOD Morello

AROf

2B'o

LAAO Mt Beagle~RO la P ;fAO Nlell0

\

pAAO GlenollonAAO We'tlond'p, AAO Pt Hll1'rl' ~

)-' --<AAO Dolmulr Jo-'EOC MuggletonAAa Slee£] Creekp )-J

AAO aUlbetY.\AAa Pine RldQ'! ;lAO Fgl'lie

AAO Hodg'l/' AAO T~en ~AO '(00010;;0' P AAO Sowpit Creek

ROM'A AAO Wotlonooko,p po AAO Beaufort pAAO PickonJinnlO

APJJ COOliboh{fAAtJ}rle \ fJAAO Slyln CreekAAO Bonnollen --< . ....AAO R1chmondr<AAO Trofford Pork

AAO Arbrooth.cr tJ >-'AAO Dirmdo P \ '" Prl .AAO Binyo AAa Blythewood AAO Bengollo

AAa lofne'"" .....- P AAO Bordloming,-3850 u 2339 ;J, - ~~AAO 80ny Creek

AAO Volley Downp: AAa Moffro j.1~o"PAPNWollobello

AAO Hotlyrood rf P 1~155 0 ----.0 2340 AAa Lyndon COlle"- APN Snoke Crpk AAa Lorelle

pAPN Bolgownie W 12"'21 P 016235I p AAa ComborngoAAO Bruc.dole.-: p.

p AAa Boondoro 108"'1

APN Ob.rino AAO SUnnybonP 0

AAO Glentulloch Ip

AAQ Kildare la

AAO BindonQap

2622o

AAQ We"orav, l.er

AAQ WeslQrove 3.0

AOE I (R.ids Dome)p

A/JI) KilloronfJ

AOP SttotnmOrll

~.AAO GI.nroy

MITCHELLo013951

pADP Donnybrook

1604o

tJ PEC Warron;

AAO Womblebonk JJ

PEC Crystal brook fJ

PEC Tooloombillo s:J

01603

01605

04185

4585

.. ADP Scolby

11354o

pUPR MUl19ollolo I

pAOP Dulbydillo

04687

MORVEN

Q,'2741

1773

ARO 9 (Gunnewin)p1--c::-c-::C'C-----------------;::-;o;iB<i------------------------i;;;:;;:;-;:: :;;;;;;;;-+;:;:;:;_UKA Buruooo I

26°00' t ~MITCHELL 0 ,09B4 ROM A 0'''60 CHINCHILLA

AOP AlbO.... , ,

AOP TreQale

Orion MarYllol.pOrion LowOOdp

MILLMERRANo

,O'PSO Millm.rran

fJPSO Tipton

p'PSO Yorrolo

10 {DolbytfAL8Y

;/'SO llg log

INGLEWOODo

pPSOWOglJObo

pPSO Tinker Cr..k

PSO Wllkl'p

Ppsa Stohon ereek

,O'PSO Kogons S

~SOKogon

JJ1UKA Bro.mar

p-WKA Uronilla

016354

12639 0 0 11645

J1UKA Tingon

347682822 0 0 156063o WPA Commoron,O' 34814

GOONDlWINDI 0 0'399'

./...~ f1WPA MoogolOn/----./ ...

\ QUEENSLANDP ,

UKA Goondiwindi ""- ... _-........_ ,-,---",,' -..... .. "'-

NEW SOUTH WALES

U A Minimo,.

UKA Booberonnop

,-',(

.. .." UKA Mottnlyre..- ',_r-- , ... .....-, 0 4032

o468~

04028

fiJKA Dolk.itn

0134

UKA Yorrondine,O'

133 590o

0132

PUTP Mourochon

0 4044

p-UTG Tolov.ro

UKA Goulomol'}j UKA Trol"p

127 UKA Moomboh• P

04045

04043

UKA Kotootop'

013820

J-lKA Moron

o2414

0.9

04042

04918

DIRRANBANDIo

016788

04921

2770 J)OA Neobul Creeko P """ 1100A Hooloh Creek

~OOA Nooglllo

OZ976

016831

0149

03476

016735

03819

0'00

11 NAM wnYlnbirro

01482

o1483

01485

013586

0169

Hor W.rrl~IO .. 0"'024,,/ .o'UKA Booml 0 4185

,/,/ .~We<d"2 457BO pUKAL,mOb<r' \ •• _ TEXAS

I ~ ~132 , 0. 04121""-. '"",

.. ) Euo KinnimJf 04611

... "

l ~OL':6i7:.:' -:::;::;:- -L--L tl 4_'6_'_0=----::0~4_0_9_9;;;;;;;;;:-----------------------L--------------- l' _29°00' 148000' / 150000' 29°00

147°00 l 151°30'

;esso Gil Gil,,,

..-AOP Boheno,

/_ADP Borodlne Wesl

• e;~"~:dY Comp

1 -=::"""~---------------------7L--t;:;;;:;_;::;--_------------.:""",,---------------------- "-i4!;,--r;;:;-;:;;:;- -+,{Ul!K>.!!.uMllJilill•..• o,'__"_7_' -1,,·od ~ SURAT 01149> DALRY P

HOMEBOIN 3477 UKA Kif'lCOftlp UTG '(ombUQlej1 011740 llKA CooIOOtnQI}t1UKA Conclomine05 0 UKA80inbillf ..UKA Myoll Cr"k 0 16029 UKACobboreeno UKA cf. . UKAWomboCreek

08654 011 I \ 013682 a Wieamblllo r:f

62 UKA COIgoonrr . I f:J• Jo-' SURAT 40~3 UKA Rog.raP' ...AIKATey UKA Lowson

DOA H I h 0 0 138090 j..r I11866 11954 3475 {J 000 015101 UKA D"d OUTA Myro

o 0 0 04052 04051 UTE M.ondorro 12569 rr 0111 ,on

\

GLENMORGAN J:1 0 ~ • UK' U""II,o '7!l1' J:1 Io 1303~KA L.ichnordt TARA((314J41

UIN Redcop MEANDARRA 0 j 13160 0 0 12190t1 ,..UKA W.rlboo. 1503600 13139

/

P 173L8~ llM6 ;JJKA Toro ff d SO Kumborillo EUTE Polomo 016654 0 .JJKAToraS UKARoek Creek

UINEcho~ll, 0 Pt1 ~ UKA Lynrock OJ24"'7 14742 J:fKA Mo..moduo rlPSO Kumborillo

.__--"7:;;:-;;::::::::; 01655

/ 0/7986

..LJKA Pogo, '"0

11410 •• rl"_-- ~KA Glen.orn UKA CObowin..._f:J - ;.JUK A Pi.bold

UKA Bolonn.... p-UKA Dongo \ UKA Cabowin E.JJKA Kinkobillo dJKA Toombillo E PSO Durobillo C~IL PLAINS

UKA Worroo rfUKA Moullit jfKA Bog;o Creek P ,O'UKA . PSO Ounmor. Creek .... a 0- PSO eec,1 PlainsP '" I P'UKA Bidgel . Toomblllo rr PSO c.eil Plain. W P APN Horron.

ure BoxIei9h UKA Brigolow CrHk p-UKA Lldd~+~89 ..... PSOOurobillo WUKA Elgin ff UKA Tortt\Otf \ ,0' 0 r:f PSO Cecil Plains S

a .Cl ....UKA Coomritn UKA Hoyes Creek....c ;JJKA Middl. Ct"~083UKA Wongonul ,.UKA Wung.r ~ UKA Moonie N 0

UKA Yooroogo JJUIB Mamoree \ 0 15124 JfUKA MuodogoiUK' S"'''wood >f Cl MOONIE

UKA MOOnie~52510 p-UKA Rlitr'ol

{1 31860 030316UKA Su'sex Downs J 031860 016984

UTA AlIonN UKA Killoloep' UKA DoclIerilt

;:rUKA Kooroo" J6234 0 I a J1. p UKA W.ir

UTG F,',.ol' JJK' Flinton UKA c..owclerD' rl UKA BooroondoorJ p - UKA Curro' • gf1 Jo-'UKA Crowder E

UKA Alt n W • UKA Alton 17435o tJ I ;::fUKA Alton E .P'UKA Worrigobbie

1 c7iT,,'Wi ~02::2_4 ~/1~.~U~K~.~S~t~G~o~.,;;o~;;;;;;_-----'U~K~.~M!C'~Dt~;'~O,__;;;;""7.fJ~U~K~.;::'.~I~to~'i"='~IO'--------------------t_---_-+__~ldlJewo28°od ~ 80LLON 397 ST GEORGE 'ff UKA Kenlucky,O' OJ6039 GOONDIWINDI

DIRRAN8ANDI 0 0~5 0{] ;1UKA re.lbo WPA Billo Bilta.O" 12088ST GtORGE 0 4399 02973 I ~ 22140 0 !JKA Yorrill Creek

OZ686 0 3820 0 147 04401 ,I1UKA Ulo Ulo 161400 P 12714

!fUKA Worrie 013744 0JJ73 10284

rlBridg. Nmgnom 11743 0 11950Jo-' 11 UKA Tolwood 0 B'" 0

pUKA Geroldo 0 a.".

WPA Nomby' .WPA Thompson"f:f fj 16~a.qO

o 20

SCALE

40

1:1000000

60

pUKATey Petroleum exploration well .'----. Line of correlation diagroms

... UKA Binky Petroleum e~ploration well usedfor correlation diagrams

Edge of Surat Basin

Wireline logged water borewith registered number

State boundary

Wire/ine logged water bore with registerednumber used for correlation diagrams

1ST GEORGE Index to / 250000 sheet areas

AAO LORElLE NO 1PLATE 2

•. ~ 11f vI,;,) C:,c',S

EA S T

Hullon Sandstone

Euromboh Formation

Evergreen Formation

TO 1972'

0/,1,/616

PreCIpice Sandstone

Wondoon Formation

72.0'

UKA BINKY NO 1

1935'

1490'

Spnngbok Sandstone

Wolloon Cool Measures

870'-----

Westbourne Formotion

Gubberomundo Sandstone

UKA CONLOI NO 1

Orollo Formation

7115'

4940'

17115'

IO~

11590'

Moooo Sondston8

Concoster Member

Bungil Formation

830'

3270'

.s,.o'

AAO BONY CREEK NO 1

1990'

4348'

4493'

8715'

~

~2470'

f Wafloan Coo! MeasuresDatum - lop a

Basa! Jurassic uncanfarmity

22!Q.'

1270'

Aquifer sequences

Tr/assic sedimtlnts

3218'

2730'

~: Basemenl racksXx

4210' ,

4260'

-------16.s0'

1980'-----

910'

AAO BINYA NO 1

Concoster Member

TO 3929'

GLENROY NO 1 ~Coreeno Memb

4e;$

------

2 7015'

AAO

126 0'

24150'

100 km,'0

Slructurtl contour ontop of Wafloon,mtllrtls btltow stla /tllltI/

Oni/ ho/tI ustld f~r

corr,/allon; stlctlon//ntl

o

1$00

o~,

3892

\~~~,o,.>~'-!~ 3260'. ~

'~i -:=-.....'~

:: ~~690'TO 3221'

Precipice Sandstone

29154'

31415'

AOP STRATH MORE NO 1

_eo

1820'

3100'

LOCALITY DIAGRAM

/000

o•SI Geor~e 0

<~~ 2620'. --

1000

xXxXxXxXx

TO 28415'

o

o

Foul!

Lim't of Wal/oon

Outcrop of Wal/oon

Outcrop lop of Wo/!oon

148 0

o

~8INYA· RomaSTRATHMORE

BONY CGLEN OY~

600 0

2860'

o

Walch Pty Ltd" Hobart, AustraliaPrinted by: Mercury-

SCALBY

1000'

/

C LOG CORRELATIONELECTRI

OF PETROLEUM EXPLORATION

WELLS FROM WEST TO EAST

(MORVEN TO MILES)

AOP SCALBY NO 1

TO 2713'

740'

2430'

Scale

lOOm

o 0

200m

1500'

1000'

140'AOP ALBA NO 1_____

MemO" r"'{':

Bosement

Concoster

Hullon Sandstonfl!

Hooray Sandstone

1730'12150'

Westbourne Formation

1960'1470'

Adori Sandstone209$'1600'

Birkheod Formation

23e~1910

Precipice Sandstone27015'

Codno-owie Formation

Evergreen Formation215615

AAO LORElLE NO 1PLATE 2

•. ~ 11f vI,;,) C:,c',S

EA S T

Hullon Sandstone

Euromboh Formation

Evergreen Formation

TO 1972'

0/,1,/616

PreCIpice Sandstone

Wondoon Formation

72.0'

UKA BINKY NO 1

1935'

1490'

Spnngbok Sandstone

Wolloon Cool Measures

870'-----

Westbourne Formotion

Gubberomundo Sandstone

UKA CONLOI NO 1

Orollo Formation

7115'

4940'

17115'

IO~

11590'

Moooo Sondston8

Concoster Member

Bungil Formation

830'

3270'

.s,.o'

AAO BONY CREEK NO 1

1990'

4348'

4493'

8715'

~

~2470'

f Wafloan Coo! MeasuresDatum - lop a

Basa! Jurassic uncanfarmity

22!Q.'

1270'

Aquifer sequences

Tr/assic sedimtlnts

3218'

2730'

~: Basemenl racksXx

4210' ,

4260'

-------16.s0'

1980'-----

910'

AAO BINYA NO 1

Concoster Member

TO 3929'

GLENROY NO 1 ~Coreeno Memb

4e;$

------

2 7015'

AAO

126 0'

24150'

100 km,'0

Slructurtl contour ontop of Wafloon,mtllrtls btltow stla /tllltI/

Oni/ ho/tI ustld f~r

corr,/allon; stlctlon//ntl

o

1$00

o~,

3892

\~~~,o,.>~'-!~ 3260'. ~

'~i -:=-.....'~

:: ~~690'TO 3221'

Precipice Sandstone

29154'

31415'

AOP STRATH MORE NO 1

_eo

1820'

3100'

LOCALITY DIAGRAM

/000

o•SI Geor~e 0

<~~ 2620'. --

1000

xXxXxXxXx

TO 28415'

o

o

Foul!

Lim't of Wal/oon

Outcrop of Wal/oon

Outcrop lop of Wo/!oon

148 0

o

~8INYA· RomaSTRATHMORE

BONY CGLEN OY~

600 0

2860'

o

Walch Pty Ltd" Hobart, AustraliaPrinted by: Mercury-

SCALBY

1000'

/

C LOG CORRELATIONELECTRI

OF PETROLEUM EXPLORATION

WELLS FROM WEST TO EAST

(MORVEN TO MILES)

AOP SCALBY NO 1

TO 2713'

740'

2430'

Scale

lOOm

o 0

200m

1500'

1000'

140'AOP ALBA NO 1_____

MemO" r"'{':

Bosement

Concoster

Hullon Sandstonfl!

Hooray Sandstone

1730'12150'

Westbourne Formation

1960'1470'

Adori Sandstone209$'1600'

Birkheod Formation

23e~1910

Precipice Sandstone27015'

Codno-owie Formation

Evergreen Formation215615

UKA COQMRITH NO 1PLATE 3

WEST

ELECTRIC LOG CORRELATION

OF PETROLEUM EXPLORATION

WELLS FROM WEST TO EAST

(MORVEN TO CEelL PLAINS) UKA LYNROCK NO 1

>00

I;'Grimen Creek Formotlon

Surat Silts loneEA S T

Springbok Sandstone

Morbur9 Sandstone

Walloon Cool Measures

Gubberomundo Sandstone

HO-----i

psa CECIL PLAINS NO 1

Westbourne Formation

psa OURABlllA NO 1

'00

2520'

1280

Hutton

Sandstone

Orollo Formation

2:390

UKA PAGET NO 1

.eo·

1, Moogo Sandstone,, no'

,,

"

:noo'--

.;:~

;~ ~" ..~:I

UKA CABAWIN NO 1

Ooncoster Member

Bungil formotion

20S0

--.2 r660· I

'880-

--1180'

-

~ I=,

Wondoon ScoleHelidon Sandstone

formation 0 0

I .~'\Roef/view Formation

.250

lOOm

'00·

1200'"

, 300",

0/A/617

Careena

Member

....

:'.

lleo

29.!9

/

?

!

/

80so1 Jurossic /Inconformity

Aqudtlr st!quenCIJS

80semenl rocks

Triossic SlIdlfrltlnfs

Oolum z fop of Wo/loon Cool Mtlo$ur,s

/

:Jj

/'1

2325'

,<<

""{> \

<-rl~--("" - __~.~06~0··

TO 5004'

980'

'"UKA BALONNE NOl ~

"0 /6~

2950'

S/r/lcfur. con/our on

lop of Wo/loon,m81rlS b8!OW SlfO 1111111'

O~ '~?__....:'O",0 'm

.•.

Drill hol, uud for.----0-- con.tallon; s,et/on

J;n.

TO 394'"

l

o•Sf Geofge

HO

LOCALITY DIAGRAM

DOA NOOGILLA NO 1

Sural Siltstone

Limit of Wo/loon

Fau/l

Outcrop of Wo/loon

Outcrop fop of Wo/loon

Coreeno Member

'"

Gnmon Creek Formation

TO 2713

Printed by Mercury--Walch Pty Ltd., Hobart, Australia

ADP ALBA

2430

Hullon Sondstone

Ooncosler Member

'"

Basement

1910'

Hooray Sondstone

1250'

Everoreen formatIon2565

Adori Sandstone1600'

PreCIpIce Sandstone2105

Codno-owie Formation

Birkhead Formation

Westbourne Formation

_______1~·

UKA COQMRITH NO 1PLATE 3

WEST

ELECTRIC LOG CORRELATION

OF PETROLEUM EXPLORATION

WELLS FROM WEST TO EAST

(MORVEN TO CEelL PLAINS) UKA LYNROCK NO 1

>00

I;'Grimen Creek Formotlon

Surat Silts loneEA S T

Springbok Sandstone

Morbur9 Sandstone

Walloon Cool Measures

Gubberomundo Sandstone

HO-----i

psa CECIL PLAINS NO 1

Westbourne Formation

psa OURABlllA NO 1

'00

2520'

1280

Hutton

Sandstone

Orollo Formation

2:390

UKA PAGET NO 1

.eo·

1, Moogo Sandstone,, no'

,,

"

:noo'--

.;:~

;~ ~" ..~:I

UKA CABAWIN NO 1

Ooncoster Member

Bungil formotion

20S0

--.2 r660· I

'880-

--1180'

-

~ I=,

Wondoon ScoleHelidon Sandstone

formation 0 0

I .~'\Roef/view Formation

.250

lOOm

'00·

1200'"

, 300",

0/A/617

Careena

Member

....

:'.

lleo

29.!9

/

?

!

/

80so1 Jurossic /Inconformity

Aqudtlr st!quenCIJS

80semenl rocks

Triossic SlIdlfrltlnfs

Oolum z fop of Wo/loon Cool Mtlo$ur,s

/

:Jj

/'1

2325'

,<<

""{> \

<-rl~--("" - __~.~06~0··

TO 5004'

980'

'"UKA BALONNE NOl ~

"0 /6~

2950'

S/r/lcfur. con/our on

lop of Wo/loon,m81rlS b8!OW SlfO 1111111'

O~ '~?__....:'O",0 'm

.•.

Drill hol, uud for.----0-- con.tallon; s,et/on

J;n.

TO 394'"

l

o•Sf Geofge

HO

LOCALITY DIAGRAM

DOA NOOGILLA NO 1

Sural Siltstone

Limit of Wo/loon

Fau/l

Outcrop of Wo/loon

Outcrop fop of Wo/loon

Coreeno Member

'"

Gnmon Creek Formation

TO 2713

Printed by Mercury--Walch Pty Ltd., Hobart, Australia

ADP ALBA

2430

Hullon Sondstone

Ooncosler Member

'"

Basement

1910'

Hooray Sondstone

1250'

Everoreen formatIon2565

Adori Sandstone1600'

PreCIpIce Sandstone2105

Codno-owie Formation

Birkhead Formation

Westbourne Formation

_______1~·

SOUTH

Basement

Triassic .sedlments

Hufton Sondstone

Doncoster Member

Mooga Sandstone

Gubberomundo Sandstone

Bungil Formation

Pil1igo Sand tsane

Orollo Formol'"

Walloon Cool Meosures

0/A/618

TO SOUTH

BOOMI)

Coreena Member

428a'

5179'

ESSO KINNIMO NO 1

ELECTRIC LOG CORRELATION

OF PET ROLE UMWELLS F EXPLORATION

ROM NORTH

(GUNNEWIN TO

~~'

2440'

~ . 313805'

) - ",,'.i.

2410'

PLATE

4020' I

Mereurv-Walch Pty Ltd Hob" art, AustraliaPrinted by:

Grimon Creek Formotion

Surat Siltstone

1250

HARBOURSIDE

WERRINA NO 2

~.... I --<;{;-.:/ I"" I

'06110'

TALWOOD NO 1

820'

UKA

1125'

----

UKA ALTON NO 1

/

UKA WUNGER NO 1

!llO'

1560'

2000'------

UKA L'T'NROCK NO I

850'

1400'

1840'

3380'

4360'

4060'

/

/'

UKA WERIBONE NO 1

1440'

Surot Sillstone

Coreeno Member

M'T'ALL CR NO 1

3490'

2940'

3~'

UKA

2570'

80$01 Juross'le unconformtly

Dotum z fop fo Walloon Cool Meosures

Aquifer sequences

2970'

AAO BRUCEOALE NO 1

/

Triossic sir'"uffflllnfs

P(Jrm/(]n slrJ",fm/1nls

Basemenl rocks

~4500'

/

AAO

3961'

2410'

----);,)3'

~.

Doncoster Member540'

'0___~,~__ j~O .mo

I~O"

AAO YANAlAH

1795'

Moot1Q S... and stone

Weslbourne F .ormotlon

11$1

Dralla Formal''"

L

SprinQbok 5 1105'cndslone

Gubberamunda Sandstone

___________ '603'

AAQ KAUMA NO 1

____~B~"~o~n~;~'~~~~,o.. ormofion 410'

Limif of Wolloon

Du/crop of ,.,,.,olloon

Du/crop fop of Wo/loon

Fault

o

o

",

oo

NORTH

Scale

o 0

500'

lOOm

200m

1000' 300m

~~ ~":!':O L_OCALlTY DIAGRAM

2120'

Hullon Sond Is one

1996'

Triasslc sed Imen!s

1846'

Basement

1410'

890'

Eyeroreen Formotion

Precipice Sandstone

Eurombah Formotion

Walloon Cool Measures

.:;""-:', \ 94)tll ~ .)

COplJ S

SOUTH

Basement

Triassic .sedlments

Hufton Sondstone

Doncoster Member

Mooga Sandstone

Gubberomundo Sandstone

Bungil Formation

Pil1igo Sand tsane

Orollo Formol'"

Walloon Cool Meosures

0/A/618

TO SOUTH

BOOMI)

Coreena Member

428a'

5179'

ESSO KINNIMO NO 1

ELECTRIC LOG CORRELATION

OF PET ROLE UMWELLS F EXPLORATION

ROM NORTH

(GUNNEWIN TO

~~'

2440'

~ . 313805'

) - ",,'.i.

2410'

PLATE

4020' I

Mereurv-Walch Pty Ltd Hob" art, AustraliaPrinted by:

Grimon Creek Formotion

Surat Siltstone

1250

HARBOURSIDE

WERRINA NO 2

~.... I --<;{;-.:/ I"" I

'06110'

TALWOOD NO 1

820'

UKA

1125'

----

UKA ALTON NO 1

/

UKA WUNGER NO 1

!llO'

1560'

2000'------

UKA L'T'NROCK NO I

850'

1400'

1840'

3380'

4360'

4060'

/

/'

UKA WERIBONE NO 1

1440'

Surot Sillstone

Coreeno Member

M'T'ALL CR NO 1

3490'

2940'

3~'

UKA

2570'

80$01 Juross'le unconformtly

Dotum z fop fo Walloon Cool Meosures

Aquifer sequences

2970'

AAO BRUCEOALE NO 1

/

Triossic sir'"uffflllnfs

P(Jrm/(]n slrJ",fm/1nls

Basemenl rocks

~4500'

/

AAO

3961'

2410'

----);,)3'

~.

Doncoster Member540'

'0___~,~__ j~O .mo

I~O"

AAO YANAlAH

1795'

Moot1Q S... and stone

Weslbourne F .ormotlon

11$1

Dralla Formal''"

L

SprinQbok 5 1105'cndslone

Gubberamunda Sandstone

___________ '603'

AAQ KAUMA NO 1

____~B~"~o~n~;~'~~~~,o.. ormofion 410'

Limif of Wolloon

Du/crop of ,.,,.,olloon

Du/crop fop of Wo/loon

Fault

o

o

",

oo

NORTH

Scale

o 0

500'

lOOm

200m

1000' 300m

~~ ~":!':O L_OCALlTY DIAGRAM

2120'

Hullon Sond Is one

1996'

Triasslc sed Imen!s

1846'

Basement

1410'

890'

Eyeroreen Formotion

Precipice Sandstone

Eurombah Formotion

Walloon Cool Measures

.:;""-:', \ 94)tll ~ .)

COplJ S

ELECTRIC LOG CORRELATION OF PETROLEUM EXPLORATION WELLS FROM NORTH TO SOUTH PLATE 5

(WANDOAN TO BOOM!)

UKA MACINTYRE NO 1

Bungl! Formation

Coreena Member

Doncoster Member

ESSO KINNlMO NO 1

1565'

1210'

--------2:000'

300!!

--UKA MINIMA NO 1 '400

12:10'

UKA MOONIE NO 1

18eo'

2050'

180'

UKA CABAWI N NO 1

BunQil Formation

Coreena Member ).660 )

Doncasler Member

UKA UNDULLA NO 1

980'

1270'

Moogo Sandstone

BunQil Formation

300 ...

200 ...

>0_

Scaleo

"'0

1000'

2"

".

S/ruclur. conlour onlop of WaJloon,m,'rlS IJ.low 6.a l.v.1

!l0 00 ~ ...~~'-~'

Drill 1101. us.d for---e- cou.la/ion. Slcfion

lin.

o

/000

o•Sf George

LOCALITY DIAGRAM

o

Llml/ of Walloon

Faull

Oufcrop lop of Wolloon

Oulcrop of Wolloon

oo

Bosement

Triassle sediments

Wolloon Coal Measures

Pilliga Sandstone

Hutton Sandstone

Orallo Formallon

MooQa Sandstone

O!A/619

~TO 5195'

Z4_0

P.rmlan s.dlm.nls

8os.m.nt rocks

4080'

Oolum z lop of Wolloon Cool M.osur.s

5 C : Seal, change

Q Q 80so1 ';urossic unconformlly

Printed by: Mercury-Welch Pty Ltd., Hobart, Australia

3!180'

(~

~---,<-le/

I.....~":.<.:

/: >,

4880'

--------289!1

4e30'

2900'

2400'

45.0

/

!l1l0'

I/

TO 6106"

< II

'::'/3350'----2125

III~'

Orallo Formation

UKA PICURDA NO 1

UKA DOGWOOD NO 1

4'60'

-- /2490'

/-----------2765''"

"." ."

:;':

4930'

3220' /-------3320' se

::....::. -----435'

UKA CONLOl NO 1

710'

3130'

1010'

3370'

Orollo Formotlon

no' 3380'- 4070'1090' 980' - 2;00,

Springbok Sandstone3!140'1715' '00' 1120' 2920' -zoo'

Westbourne Formation

Wolloon Cool Measures

Gubberamundo Sandstone .:.::::

UKA BURUNGA NO 1

EverQreen Formaftonse

!I_aa'

'1100'

1------- 37!1'

4_9C"

,Precipice Sandstone ~

~• O.

Z030' / TO 41311'

~4940'

Triossic sediments

se

!l10'

1060'

Wollaon Cool Measures

300'

Hullon Sondstone

Euromboh Formation

f.. , .1:, 9.4)

,1 1 h ~

Cop "6 5

ELECTRIC LOG CORRELATION OF PETROLEUM EXPLORATION WELLS FROM NORTH TO SOUTH PLATE 5

(WANDOAN TO BOOM!)

UKA MACINTYRE NO 1

Bungl! Formation

Coreena Member

Doncoster Member

ESSO KINNlMO NO 1

1565'

1210'

--------2:000'

300!!

--UKA MINIMA NO 1 '400

12:10'

UKA MOONIE NO 1

18eo'

2050'

180'

UKA CABAWI N NO 1

BunQil Formation

Coreena Member ).660 )

Doncasler Member

UKA UNDULLA NO 1

980'

1270'

Moogo Sandstone

BunQil Formation

300 ...

200 ...

>0_

Scaleo

"'0

1000'

2"

".

S/ruclur. conlour onlop of WaJloon,m,'rlS IJ.low 6.a l.v.1

!l0 00 ~ ...~~'-~'

Drill 1101. us.d for---e- cou.la/ion. Slcfion

lin.

o

/000

o•Sf George

LOCALITY DIAGRAM

o

Llml/ of Walloon

Faull

Oufcrop lop of Wolloon

Oulcrop of Wolloon

oo

Bosement

Triassle sediments

Wolloon Coal Measures

Pilliga Sandstone

Hutton Sandstone

Orallo Formallon

MooQa Sandstone

O!A/619

~TO 5195'

Z4_0

P.rmlan s.dlm.nls

8os.m.nt rocks

4080'

Oolum z lop of Wolloon Cool M.osur.s

5 C : Seal, change

Q Q 80so1 ';urossic unconformlly

Printed by: Mercury-Welch Pty Ltd., Hobart, Australia

3!180'

(~

~---,<-le/

I.....~":.<.:

/: >,

4880'

--------289!1

4e30'

2900'

2400'

45.0

/

!l1l0'

I/

TO 6106"

< II

'::'/3350'----2125

III~'

Orallo Formation

UKA PICURDA NO 1

UKA DOGWOOD NO 1

4'60'

-- /2490'

/-----------2765''"

"." ."

:;':

4930'

3220' /-------3320' se

::....::. -----435'

UKA CONLOl NO 1

710'

3130'

1010'

3370'

Orollo Formotlon

no' 3380'- 4070'1090' 980' - 2;00,

Springbok Sandstone3!140'1715' '00' 1120' 2920' -zoo'

Westbourne Formation

Wolloon Cool Measures

Gubberamundo Sandstone .:.::::

UKA BURUNGA NO 1

EverQreen Formaftonse

!I_aa'

'1100'

1------- 37!1'

4_9C"

,Precipice Sandstone ~

~• O.

Z030' / TO 41311'

~4940'

Triossic sediments

se

!l10'

1060'

Wollaon Cool Measures

300'

Hullon Sondstone

Euromboh Formation

f.. , .1:, 9.4)

,1 1 h ~

Cop "6 5

PLATE 7

ESSO KINNIMO NO 1

Basement

Coreena Member

Orallo Formation

Bungil Formation

Moogo Sandstone

Ooncaster Member

Pdliga Sandstone

Hutton Sandstone

O/A/621

Walloon Coal Measures

Triassic sediments

4299'

3805'

Dotum = bau 01 PI/"ga Sandslone

Aquifer sequences

TO 5195'

Triassic sediments

Xxx x Basement racks

X

2440'

~~ Basal Jurassic unconlarmJly

AMOSEAS

BOHENA NO 1

',0 100 km~------'-~'o

Slructure conlour on /)OS6 of ,)uross/c; mt/lres below sea level

--------~ ___.J33"

LOCALITY DIAGRAM

AMOSEAS

BARADINE WEST NO 1

o

~'SANDY CAMPK"". BARAOINE. /WEST

') 0

~ 'I/

146"30'

'"460'

//------

~-

~c~ I~

~ ~1 ' I

* 950' L '150'Xx

~:r •

XxXx

l(XxXxXxXxXxXxXxXx 1240' XX

)fXx xXx XxXx XxXx XxXx Xxx Xx

XTO 2425

Limil of Sural Basin

Fou/l ~ Drill hole used for correlalion; section line

Contours of/er Bour/rtl, How!r.e, a Saheihnu, 1974.

lKINNIMO NO 1 TO SANDY CAMP NO 1 )

BOC SANDY CAMP NO 1

WELLS IN THE SOUTH

ESSO GIL GIL NO 1

OF PETROLEUM EXPLORATION

ELECTRIC LOG CORRELATION

200",

300 ...

Scole

o 0

lOOm

Basement

1900'

1490'

900'

1000

PilliQa Sandstone

Bungil Formation

Oralla Formation

Mooga Sandstone1000'

Bungil Formation

Bosemenf

Hutton Sandstone

Mooga Sandstone

Gubberomunda

Coreena Member

Orollo Formation

Surot Siltslone

Triassic sediments

Precipice Sandstone

Evergreen Formation

Walloon Coal Measures

Doncaster Member

Weslbourne Formation

Grimon Creek Formation

1 Soods!o",

$-

X

TO 6331'

1560'

,3510'

6306'

2680'

~3190'

/

---2000'

<)

I~t=

, 0

Scale

UKA ST. GEQRGE NO 1

4585'

4010'

1000'

1110'

3000'

2890'

1310'

--------------1170'

~945'

o

Adori Sandstone

26"

2145'

o

NORTH AMERICAN

WHYENBIRRA~O1280'~- , ,

o

Structure contour onfop of Ooncoslermetres below sea level

Drill hole used forcorrelation, s(Jcfionline

440' ,.

Sural Siltstone

1~O'

Coreeno Member

1010'

Doncosler Member

126~'

Bungil Formation

1~~5'

o

Limfl of Doncosler

( WUNGER NO 1 TO WHYENBIRRA NO 1 )

Foul!

UKA WUNGER NO 1

PLATE 6ELECTRIC LOG CORRELATION OF PETROLEUM EXPLORATION WELLS IN THE SOUTHWEST

Outcrop lop 01 Dancos/er

~

Outcrop of Dancos/er

Triossic sed/menls

se = Scole cllonge

Basal Jurassic unconformily

150"

Basement

Aquifer sequences

Grime" Creek Formation

o

LOCALITY DIAGRAM

Hooray Sandstone

Codno-owie Formation

Coinozoic sediments

Datum: lop of Dancas/er Member

Xx)( x Bosemtnl rocksXx

•Printed by: Mercury-Walch Pty Ltd., Hobart, Australia

0/A/620

PLATE 7

ESSO KINNIMO NO 1

Basement

Coreena Member

Orallo Formation

Bungil Formation

Moogo Sandstone

Ooncaster Member

Pdliga Sandstone

Hutton Sandstone

O/A/621

Walloon Coal Measures

Triassic sediments

4299'

3805'

Dotum = bau 01 PI/"ga Sandslone

Aquifer sequences

TO 5195'

Triassic sediments

Xxx x Basement racks

X

2440'

~~ Basal Jurassic unconlarmJly

AMOSEAS

BOHENA NO 1

',0 100 km~------'-~'o

Slructure conlour on /)OS6 of ,)uross/c; mt/lres below sea level

--------~ ___.J33"

LOCALITY DIAGRAM

AMOSEAS

BARADINE WEST NO 1

o

~'SANDY CAMPK"". BARAOINE. /WEST

') 0

~ 'I/

146"30'

'"460'

//------

~-

~c~ I~

~ ~1 ' I

* 950' L '150'Xx

~:r •

XxXx

l(XxXxXxXxXxXxXxXx 1240' XX

)fXx xXx XxXx XxXx XxXx Xxx Xx

XTO 2425

Limil of Sural Basin

Fou/l ~ Drill hole used for correlalion; section line

Contours of/er Bour/rtl, How!r.e, a Saheihnu, 1974.

lKINNIMO NO 1 TO SANDY CAMP NO 1 )

BOC SANDY CAMP NO 1

WELLS IN THE SOUTH

ESSO GIL GIL NO 1

OF PETROLEUM EXPLORATION

ELECTRIC LOG CORRELATION

200",

300 ...

Scole

o 0

lOOm

Basement

1900'

1490'

900'

1000

PilliQa Sandstone

Bungil Formation

Oralla Formation

Mooga Sandstone1000'

Bungil Formation

Bosemenf

Hutton Sandstone

Mooga Sandstone

Gubberomunda

Coreena Member

Orollo Formation

Surot Siltslone

Triassic sediments

Precipice Sandstone

Evergreen Formation

Walloon Coal Measures

Doncaster Member

Weslbourne Formation

Grimon Creek Formation

1 Soods!o",

$-

X

TO 6331'

1560'

,3510'

6306'

2680'

~3190'

/

---2000'

<)

I~t=

, 0

Scale

UKA ST. GEQRGE NO 1

4585'

4010'

1000'

1110'

3000'

2890'

1310'

--------------1170'

~945'

o

Adori Sandstone

26"

2145'

o

NORTH AMERICAN

WHYENBIRRA~O1280'~- , ,

o

Structure contour onfop of Ooncoslermetres below sea level

Drill hole used forcorrelation, s(Jcfionline

440' ,.

Sural Siltstone

1~O'

Coreeno Member

1010'

Doncosler Member

126~'

Bungil Formation

1~~5'

o

Limfl of Doncosler

( WUNGER NO 1 TO WHYENBIRRA NO 1 )

Foul!

UKA WUNGER NO 1

PLATE 6ELECTRIC LOG CORRELATION OF PETROLEUM EXPLORATION WELLS IN THE SOUTHWEST

Outcrop lop 01 Dancos/er

~

Outcrop of Dancos/er

Triossic sed/menls

se = Scole cllonge

Basal Jurassic unconformily

150"

Basement

Aquifer sequences

Grime" Creek Formation

o

LOCALITY DIAGRAM

Hooray Sandstone

Codno-owie Formation

Coinozoic sediments

Datum: lop of Dancas/er Member

Xx)( x Bosemtnl rocksXx

•Printed by: Mercury-Walch Pty Ltd., Hobart, Australia

0/A/620

Metres900

BORE73

~100-71o

PLATE 8

Surat Siltstone

Coreena Member

Doncaster Member

Griman Creek Formation

BORE16140

1E-100 -i>Io

MOONIE AREA

/

c

BORE127

100 -71o

900

BORE15523

1E-100 -i>Io

500

Cainozoicsediments

BORE62

100 C>I

700

500

ROMA AREA AAO BORE1445

BINYA 3850

NO 11E-100~ 320

0400

13901001020/

1170Coreena Member

680 1590300 370

830485 2120

800

600

Metres900

BORE73

~100-71o

PLATE 8

Surat Siltstone

Coreena Member

Doncaster Member

Griman Creek Formation

BORE16140

1E-100 -i>Io

MOONIE AREA

/

c

BORE127

100 -71o

900

BORE15523

1E-100 -i>Io

500

Cainozoicsediments

BORE62

100 C>I

700

500

ROMA AREA AAO BORE1445

BINYA 3850

NO 11E-100~ 320

0400

13901001020/

1170Coreena Member

680 1590300 370

830485 2120

800

600

SURAT BASiN r r),

Cl Cl8

COP~5

Cl~~ClClC) ""le)151'00''l" 150'00 It) Cl 151'30'

.:: .. 24°30

".- -.. 0° .,:::

1+ + + '-V 'f V V V V I ::.',,'"- ..... '

'- .:.....V\ + + + + + + +\ V V V r-::'·::

rJ~

(>,::V V V

... ° 0 •

V 'I) + + + + + + (:,:'i: iV (../

\ " , , .+ + + + + + \ oMonta V : • °0 '.':

--( (,::,oTheodore V C'++\V

•... 0.

+ + + + +f \~V V

....(...- ) r,":', ,.. '.

+\ V(': , 25'0dV-V) + + + + + V V " ',e :. '.'

\ .. ' :....r'" ''\ + + + + + + + JiV V : .. ;. :, ' ,

\ ' , 'r "1 + + + + + + + \ V V v::',::\'::, '

oCrocow ' '

V ,,+~ + + + + + + +\ V V i:>Jv+ Iv ' ,

+ + + + + + V V ,.. ", ', ', .'

1"1 I. '::+ + + + + V V " ." ../

• • 00 •

r"....... "

+ + + + + fV ~UndUbb~r~·. :I ' ,.......... ' .. '

0 ....

+ + + + T t IV V {:,t+-, "

+ + + + Iv V v''/+7

+ + + V ( + T

/ + +-

"V V V ".J -t T26'00'

rV V V V -t + +-

V V V -t +- +

V + +-

27°00' + 27'00'X

• + V VX X

• t ·tX X V ~ V V)

X • XI + V VX.523

X

X X X•

X X•

.420 V

X V

V Vp'1857

, V

V V V~

V V ,t")

V V V V

V V V V V V1798+

IfV V( ) V oTe,os~ V V V../ Jy

V V• (T '\.""')+

15/'00' 29'00151'30'

W.A.

I V V If" .. ' '. " " "1~ ~:, :. :,':. '.: :;'::;-'::::':

I + + II X X I~

Scale 1:\000000

20 10 0 20 40 60 80,! • , , , , , I i

,i I

, , , ,i

10 0 20 40

Volcanics and sediments of the 'Kuffung Formation I

and equivalents

Sandstone, siltstone, shale, and their metamorphosed equivalents:Timbury Hills Formation and Wandella Formation

Granite and granodiorife

Schist and gneiss

Gabbro and ultrabasic rocks

100KILOMETRES

60 MILES

!""",,,,

-~/ooom}--</OOOm

o

Outcrop margin of basinal sediment

Geological boundary

Fault

Structure contours (below sea level)

Petroleum exploration well

Wireline -logged water bore

Q/A503

Plate 9 Structure contour, top of basement,

SURAT BASiN r r),

Cl Cl8

COP~5

Cl~~ClClC) ""le)151'00''l" 150'00 It) Cl 151'30'

.:: .. 24°30

".- -.. 0° .,:::

1+ + + '-V 'f V V V V I ::.',,'"- ..... '

'- .:.....V\ + + + + + + +\ V V V r-::'·::

rJ~

(>,::V V V

... ° 0 •

V 'I) + + + + + + (:,:'i: iV (../

\ " , , .+ + + + + + \ oMonta V : • °0 '.':

--( (,::,oTheodore V C'++\V

•... 0.

+ + + + +f \~V V

....(...- ) r,":', ,.. '.

+\ V(': , 25'0dV-V) + + + + + V V " ',e :. '.'

\ .. ' :....r'" ''\ + + + + + + + JiV V : .. ;. :, ' ,

\ ' , 'r "1 + + + + + + + \ V V v::',::\'::, '

oCrocow ' '

V ,,+~ + + + + + + +\ V V i:>Jv+ Iv ' ,

+ + + + + + V V ,.. ", ', ', .'

1"1 I. '::+ + + + + V V " ." ../

• • 00 •

r"....... "

+ + + + + fV ~UndUbb~r~·. :I ' ,.......... ' .. '

0 ....

+ + + + T t IV V {:,t+-, "

+ + + + Iv V v''/+7

+ + + V ( + T

/ + +-

"V V V ".J -t T26'00'

rV V V V -t + +-

V V V -t +- +

V + +-

27°00' + 27'00'X

• + V VX X

• t ·tX X V ~ V V)

X • XI + V VX.523

X

X X X•

X X•

.420 V

X V

V Vp'1857

, V

V V V~

V V ,t")

V V V V

V V V V V V1798+

IfV V( ) V oTe,os~ V V V../ Jy

V V• (T '\.""')+

15/'00' 29'00151'30'

W.A.

I V V If" .. ' '. " " "1~ ~:, :. :,':. '.: :;'::;-'::::':

I + + II X X I~

Scale 1:\000000

20 10 0 20 40 60 80,! • , , , , , I i

,i I

, , , ,i

10 0 20 40

Volcanics and sediments of the 'Kuffung Formation I

and equivalents

Sandstone, siltstone, shale, and their metamorphosed equivalents:Timbury Hills Formation and Wandella Formation

Granite and granodiorife

Schist and gneiss

Gabbro and ultrabasic rocks

100KILOMETRES

60 MILES

!""",,,,

-~/ooom}--</OOOm

o

Outcrop margin of basinal sediment

Geological boundary

Fault

Structure contours (below sea level)

Petroleum exploration well

Wireline -logged water bore

Q/A503

Plate 9 Structure contour, top of basement,

SURAT BASIN

~ALBY

~undubbero

IS

" /If

oMonta

11

+

+

+

+

IS

" 11

p

•

•

•

•

•

OChinchillo

•

•

IS•

•

•

• JI•

•

•

• •

•

fI

oGoondiwindi

•

•

•

•

•

•

•

••

•

IS

•

Mungindi

•

11

P 11

11

IS

•

IS

fI

~St George

IS

fI

•

•

•

•

•

•

I I 0n\ \ ~v, ,,

\ '\ \

/~\~31~S'CbJ I- I" /'/

IS

•

•

IS

1 4':',.~

949~,\~ .',.~ 0'1"1193 11

1I'J

•

•

•

ODlrranbondi

•

•

•

•

•

•

•

fI

•

•

•

IS

•

"

~Mitch.1I

+

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Mungollo1oo

•

•

•

OBoIlon

•

•

•

•

•

•

•

•

•

IS

•

•

•

•

•

•

o

•

---+200

•

•

Marvenc:e

•

•

•

•

•

•

•

,,192

<20o

29oodL.- ~:7;;~;;;,,----------------~1;-;;4~9~00~0;;,-----------J-~'--~j;15~0~0;;:0i1-or'~""---------------,1i<i5IiOo\:;0;::;0,'-----------l29°00147000' 148000 151°30'

, 94)

1\

Scale I: 1000000 Q/A 504

"11" 11111

Lower Permian alone present

100 KILOMETRES

60 MILES

Limit of Permion sediments

Base of Upper Permian

lOp of Permian in outcrop

Structure contours (below sea level)

Fault

Petroleum exploration well

Wireline-Ioqqed water bore

80,

40

60

•

----

-IOOOm-}-800m-- -700m--

---

40

i20

20

10 0

20 10 0"", ""1

Upper Permion outcrop

Plate 10 Structure contours, top of Permian sequence

SURAT BASIN

~ALBY

~undubbero

IS

" /If

oMonta

11

+

+

+

+

IS

" 11

p

•

•

•

•

•

OChinchillo

•

•

IS•

•

•

• JI•

•

•

• •

•

fI

oGoondiwindi

•

•

•

•

•

•

•

••

•

IS

•

Mungindi

•

11

P 11

11

IS

•

IS

fI

~St George

IS

fI

•

•

•

•

•

•

I I 0n\ \ ~v, ,,

\ '\ \

/~\~31~S'CbJ I- I" /'/

IS

•

•

IS

1 4':',.~

949~,\~ .',.~ 0'1"1193 11

1I'J

•

•

•

ODlrranbondi

•

•

•

•

•

•

•

fI

•

•

•

IS

•

"

~Mitch.1I

+

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Mungollo1oo

•

•

•

OBoIlon

•

•

•

•

•

•

•

•

•

IS

•

•

•

•

•

•

o

•

---+200

•

•

Marvenc:e

•

•

•

•

•

•

•

,,192

<20o

29oodL.- ~:7;;~;;;,,----------------~1;-;;4~9~00~0;;,-----------J-~'--~j;15~0~0;;:0i1-or'~""---------------,1i<i5IiOo\:;0;::;0,'-----------l29°00147000' 148000 151°30'

, 94)

1\

Scale I: 1000000 Q/A 504

"11" 11111

Lower Permian alone present

100 KILOMETRES

60 MILES

Limit of Permion sediments

Base of Upper Permian

lOp of Permian in outcrop

Structure contours (below sea level)

Fault

Petroleum exploration well

Wireline-Ioqqed water bore

80,

40

60

•

----

-IOOOm-}-800m-- -700m--

---

40

i20

20

10 0

20 10 0"", ""1

Upper Permion outcrop

Plate 10 Structure contours, top of Permian sequence

SURAT BASIN

26°00'

- 28°00'

OMundubbero

aYetmon

OCrocow

•1183Jf

A

•1298pA

•

pl402

1183p(Al

Ap•

"1426 ,.,..'5441445 ~

" 1466", ,1629 1632,.,. 1667,.,.

"',408 ",1565

+G5 "152 16,,137 "1443

1400 If ,,1580

• ,,1535Pl450

1444 '432",p

Mungindi

p'050

1094p

•

•

135s.

~'37,,1215 ,,1246

1262 £1301 1410"p I.:, 1450P

1307 1308 PI435P ,.,.1414

1468p"1405

•

•

St George

•

•

•

•

•

•

•

•

ODirronbandi

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

OBoUon

•

•

•

•

•

•

•

•

•

•

•

•

. .•

•

•

•

•

•

•

•

302p

p310

27°00'

•

2900dL~---------------~~±-;;~''-----------------';-:;4;-;;9;00~0;;;'------------.......l.-.....:

..~~,5~0:;:0;;:0;;:of,"-'r.-L..L.1-...L-~i_:;:;:_---------;-,;-5I;oO~0;;;0"------_----.J 29000

147°00148°00

151030'

28°00'

147-00'148°00'

149°00' 150°00' /5/°00' 151°30'

24°30'

24°30

"Mouro

O

,~

C.op~ 5"

p

p oMonta

++oTheodore + "

1/25-00' "25°0d

~p p

p

Scale /:/000000Q/A 505

Contour interval lOOm (below sea level)

Top ofoutcrop of the Evergreen Formation

Outcrop of Evergreen Formation

Petroleum exploration well

Wireline -logged water bore

Evergreen Formation absent

100 KILOMETRES

60 MILES

•A

80

40

6040

i20

20o'"I1I""1

10 0

20 10

Limit of the Evergreen Formation

Fault

1111111111QLO

N.T. I

w."-.

Plate 12 Structure contours, top of Evergreen Formation

SURAT BASIN

26°00'

- 28°00'

OMundubbero

aYetmon

OCrocow

•1183Jf

A

•1298pA

•

pl402

1183p(Al

Ap•

"1426 ,.,..'5441445 ~

" 1466", ,1629 1632,.,. 1667,.,.

"',408 ",1565

+G5 "152 16,,137 "1443

1400 If ,,1580

• ,,1535Pl450

1444 '432",p

Mungindi

p'050

1094p

•

•

135s.

~'37,,1215 ,,1246

1262 £1301 1410"p I.:, 1450P

1307 1308 PI435P ,.,.1414

1468p"1405

•

•

St George

•

•

•

•

•

•

•

•

ODirronbandi

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

OBoUon

•

•

•

•

•

•

•

•

•

•

•

•

. .•

•

•

•

•

•

•

•

302p

p310

27°00'

•

2900dL~---------------~~±-;;~''-----------------';-:;4;-;;9;00~0;;;'------------.......l.-.....:

..~~,5~0:;:0;;:0;;:of,"-'r.-L..L.1-...L-~i_:;:;:_---------;-,;-5I;oO~0;;;0"------_----.J 29000

147°00148°00

151030'

28°00'

147-00'148°00'

149°00' 150°00' /5/°00' 151°30'

24°30'

24°30

"Mouro

O

,~

C.op~ 5"

p

p oMonta

++oTheodore + "

1/25-00' "25°0d

~p p

p

Scale /:/000000Q/A 505

Contour interval lOOm (below sea level)

Top ofoutcrop of the Evergreen Formation

Outcrop of Evergreen Formation

Petroleum exploration well

Wireline -logged water bore

Evergreen Formation absent

100 KILOMETRES

60 MILES

•A

80

40

6040

i20

20o'"I1I""1

10 0

20 10

Limit of the Evergreen Formation

Fault

1111111111QLO

N.T. I

w."-.

Plate 12 Structure contours, top of Evergreen Formation

SURAT BASIN

148°00'

149°00'150°00'

151°00',

147000~0~'~ ~T~ "':"':'T::"':" -------------=:T::-=-.-----------------~f~-------~15;'030

24°3Q'r

24030

Mouroo

p

p

25°00'

26°00'

27°00'

OMundubbero

oMonta

OTexos

+

+

OCrocow

+ oTheodore

pI340•

.-~

pl026

...'046

pl085

+

pl125 1276

pl180 1163p.JJ ~02 1291

• ,..1112 1219p ,,1276\. Pl285 p)

+ 1153" ""1310~

"'1114 ,..

Mungindi

p

•

,..1052

,..946 948 "1040p

,..978 ,..107110e7

1023 ;;:126 '/

.,.. ~001 I ,..1098

II06pl./ pl1461195

... '037

...1030

p

p

pp

•

+

•411 450•0°·416A

•••

oDirranbondi 0°,0

( •••• •

•

• •

00 ••/~•

() •&

• ••

•

•

•

•

•

•

143

27°00'

2900dL".------~;L..LLL-.L---_;_:;~~,L---------------,144:g9~00)(0i'----------:..:....---"'--....::

..~~~OOf-L..L-I.'-.L-.L-L--L---1---'''-.:...----1!15511~00)(Oy,-----__~ 29000

147°00'148°00

151030'

28°00'

Scale 1=1000000 Q/A 506

Outcrop of Walloon Coal Measures

Petroleum exploration well

Wireline-Iogged water bore•

100 KILOMETRES

60 MILES

80

40

6040

20

Contour interval lOO m (below sea level)

20o

10 0

20 10

Limit of Walloon Coal Measures (=Birkhead Formation)

Outcrop top of Walloon Coal Measures

Fault

I i i i i i i I I 11W.A

Plate 13 Structure contours, top of Walloon Coal Measures

SURAT BASIN

148°00'

149°00'150°00'

151°00',

147000~0~'~ ~T~ "':"':'T::"':" -------------=:T::-=-.-----------------~f~-------~15;'030

24°3Q'r

24030

Mouroo

p

p

25°00'

26°00'

27°00'

OMundubbero

oMonta

OTexos

+

+

OCrocow

+ oTheodore

pI340•

.-~

pl026

...'046

pl085

+

pl125 1276

pl180 1163p.JJ ~02 1291

• ,..1112 1219p ,,1276\. Pl285 p)

+ 1153" ""1310~

"'1114 ,..

Mungindi

p

•

,..1052

,..946 948 "1040p

,..978 ,..107110e7

1023 ;;:126 '/

.,.. ~001 I ,..1098

II06pl./ pl1461195

... '037

...1030

p

p

pp

•

+

•411 450•0°·416A

•••

oDirranbondi 0°,0

( •••• •

•

• •

00 ••/~•

() •&

• ••

•

•

•

•

•

•

143

27°00'

2900dL".------~;L..LLL-.L---_;_:;~~,L---------------,144:g9~00)(0i'----------:..:....---"'--....::

..~~~OOf-L..L-I.'-.L-.L-L--L---1---'''-.:...----1!15511~00)(Oy,-----__~ 29000

147°00'148°00

151030'

28°00'

Scale 1=1000000 Q/A 506

Outcrop of Walloon Coal Measures

Petroleum exploration well

Wireline-Iogged water bore•

100 KILOMETRES

60 MILES

80

40

6040

20

Contour interval lOO m (below sea level)

20o

10 0

20 10

Limit of Walloon Coal Measures (=Birkhead Formation)

Outcrop top of Walloon Coal Measures

Fault

I i i i i i i I I 11W.A

Plate 13 Structure contours, top of Walloon Coal Measures

SURAT BASIN

148000' 149°00' 150°00' 151°00' 1"'1° 30'

141~00~0~' ~T~-----------------.:..::.:r-=:.::..-----------------=r=~----------------~.::'..'...-r'---------~=-"~·2403024°30'

")t::,s I 1.)-4)

;UI.. 1\-,

Co~5

+ ++ oTheodore +

oMonta

OCracow

II

II

28°00'

OMundubbera

(\bALBY

p pP

If

Inglewoodo

+

+

+

p p

ppp

•

oYetman

p

p

•

p+350

•

•

•

OChinchilla

•

•

•

I·,p I

I,II

I •I P

Goondiwindi,,II

I,,,II

•

Toroom(i

•p

p p

olnjune

p p •

p +p

pp p

p p pp

p

p

•

•

l:t~S:.:J.~~~~!f..:~t.:.~~G.;.~::..:..~~~~~~~---------L-----;1~4:;;9~00:;i01".L--------=~-~------...:..:~~~:OOf---L-L-L---L-----------1i15;T1~00~0""--------:::-~29°00II 151°30'

+244

I

Scale I: 1000000Q/A 508

20 10 o 20 40 60 80 100 KI LOM ETRES

Limit of Mooqa and Hooray Sandstones

Top of outcrop of Mooqa and Hooray Sands/ones

Geoloqical boundary

Fault

" trlll"l

'11'''''1111

---------

-500m-}

--450m - Structure-400m-

10

contours (below sea level)

o 20 40

~("::: ; ...\..: : .' ..'. '.':.:::.0::, ..

• °t' .•• t' •••••

•

60 MILES

Outcrop of Mooqa and Hooray Sandstones

Hooray Sandstone replaces Gubberamunda Sandstone-Mooqa Sandstone sequence

Petroleum exploration well

Wireline-Ioqqed water bore

Plate 14 Structure contours} top of Mooga and Hooray Sandstones

SURAT BASIN

148000' 149°00' 150°00' 151°00' 1"'1° 30'

141~00~0~' ~T~-----------------.:..::.:r-=:.::..-----------------=r=~----------------~.::'..'...-r'---------~=-"~·2403024°30'

")t::,s I 1.)-4)

;UI.. 1\-,

Co~5

+ ++ oTheodore +

oMonta

OCracow

II

II

28°00'

OMundubbera

(\bALBY

p pP

If

Inglewoodo

+

+

+

p p

ppp

•

oYetman

p

p

•

p+350

•

•

•

OChinchilla

•

•

•

I·,p I

I,II

I •I P

Goondiwindi,,II

I,,,II

•

Toroom(i

•p

p p

olnjune

p p •

p +p

pp p

p p pp

p

p

•

•

l:t~S:.:J.~~~~!f..:~t.:.~~G.;.~::..:..~~~~~~~---------L-----;1~4:;;9~00:;i01".L--------=~-~------...:..:~~~:OOf---L-L-L---L-----------1i15;T1~00~0""--------:::-~29°00II 151°30'

+244

I

Scale I: 1000000Q/A 508

20 10 o 20 40 60 80 100 KI LOM ETRES

Limit of Mooqa and Hooray Sandstones

Top of outcrop of Mooqa and Hooray Sands/ones

Geoloqical boundary

Fault

" trlll"l

'11'''''1111

---------

-500m-}

--450m - Structure-400m-

10

contours (below sea level)

o 20 40

~("::: ; ...\..: : .' ..'. '.':.:::.0::, ..

• °t' .•• t' •••••

•

60 MILES

Outcrop of Mooqa and Hooray Sandstones

Hooray Sandstone replaces Gubberamunda Sandstone-Mooqa Sandstone sequence

Petroleum exploration well

Wireline-Ioqqed water bore

Plate 14 Structure contours} top of Mooga and Hooray Sandstones

(II"" 1., f '.~ )

B'J\ .~"

COfj5SURAT BASIN

, 149°00' 150°00' ,14700'0~0~' -,1~4~BIO~0~0-----------------~T------------------":":"'T:...::...-----------------~15~ITOO::::0~ ~15~IO~.30'

24030'r 24°30d ~ Mourno

p

25°00' + pp +

+ oTheodore

+OMonto

25°00'

OCrocow

26°00'

28°00'

OMundubbero

+

oChinchillo

Miles? p

P .d

.d • +.d

.d .d

6DALBY

P

P P

Pp

.d .d Jf Jfp

pP

.dJf

JfJf

p

p +•

• •p •

(0) +134I •

+108Jf • InglewoodoI

+100. • •

)p • •

oGoondlwindi p

(+180)p

jjp' 24

oTexas

oYetman

•

p229

Toroome

no190p

.d203

\200

.244201

•

•

250262.

271..326

300~2

OOirronbondi

+•

•

•

+49+34.

o

28°00'

29oodL--,-L---L----.l..:.......-----.L~~~;:r---------L-----_;1~4;9;,00;0~,--------=::::",~=-L---.:::..:.....~:::LJ.'.~~~f_----------------~15:::,-;;l00:cO"',,-----------J29°00147°00' 151°30'

Scale I: 1000000 Q/A 507

Fault

Limit of Doncaster Member

Petroleum exploration well

Wireline-Iogged water bore

Outcrop of Doncaster Member

100 KI LOM ETRES

60 MILES

•

80

40

60

i I

20

40, !

20

10 0

20 10 0, " , , !, I! I

Structure contours (below sea level)

Outcrop top of Doncaster Member

--/OOm-

--50m-

.u...u u U L.J

QLD.

1

IL.

I

Plate 15 Structure contours on the top of the Doncaster Member (Wallumbilla Formation).

(II"" 1., f '.~ )

B'J\ .~"

COfj5SURAT BASIN

, 149°00' 150°00' ,14700'0~0~' -,1~4~BIO~0~0-----------------~T------------------":":"'T:...::...-----------------~15~ITOO::::0~ ~15~IO~.30'

24030'r 24°30d ~ Mourno

p

25°00' + pp +

+ oTheodore

+OMonto

25°00'

OCrocow

26°00'

28°00'

OMundubbero

+

oChinchillo

Miles? p

P .d

.d • +.d

.d .d

6DALBY

P

P P

Pp

.d .d Jf Jfp

pP

.dJf

JfJf

p

p +•

• •p •

(0) +134I •

+108Jf • InglewoodoI

+100. • •

)p • •

oGoondlwindi p

(+180)p

jjp' 24

oTexas

oYetman

•

p229

Toroome

no190p

.d203

\200

.244201

•

•

250262.

271..326

300~2

OOirronbondi

+•

•

•

+49+34.

o

28°00'

29oodL--,-L---L----.l..:.......-----.L~~~;:r---------L-----_;1~4;9;,00;0~,--------=::::",~=-L---.:::..:.....~:::LJ.'.~~~f_----------------~15:::,-;;l00:cO"',,-----------J29°00147°00' 151°30'

Scale I: 1000000 Q/A 507

Fault

Limit of Doncaster Member

Petroleum exploration well

Wireline-Iogged water bore

Outcrop of Doncaster Member

100 KI LOM ETRES

60 MILES

•

80

40

60

i I

20

40, !

20

10 0

20 10 0, " , , !, I! I

Structure contours (below sea level)

Outcrop top of Doncaster Member

--/OOm-

--50m-

.u...u u U L.J

QLD.

1

IL.

I

Plate 15 Structure contours on the top of the Doncaster Member (Wallumbilla Formation).

, " SURAT BASiN

t

~undubbero

oMonta

IngleWOO<ia

+

••

,,171

•

18311

pl77

/4}\~O,OO

S°• 40

• •

20+

11102 '"o

•11

•

11 •

. '.,' ... ,

., .. , .

' ...

•

••

•

"

14211 15211

11611 .!4~ I15111 \4;4;'---.} 47

\ ( I~ J! 1'176l32p 113p ~4 12

ROMA 11140 .~122o '-:137"

120p p\20 pl20~3 11134 pll8

120p ,157

...., 91 'Ill "i18 124 11119 14~ 12911 11 •

_ 0 m8 12~ pl45- JI48 ".- •-IO~~ 11103

- pl04 11(85) 100p

-:-,,38

~StG.orq.

~ -.

11

•

..

11119

•

•

•

ODirronbondi

11

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

0801l0n

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

••

•

•

•

•

•

•

•

•

11

•

•

l~ ~~:oo,...--------------=M:U"9~ind;'i~,--------------'--:r...JLi5C~CT----.t:.:::::Z----------l5ioQiy------'"'i& 29°00150.00 151°00' 151°30'29°od 148000' 149°00'

141°00'

14

, :~,-:-_.,.....,:---;'"":"--:--:-:--:-::--""-:-;--:--:-:-:---:--:-:-:-~:-'""""'~~~~-:-::-~~~:::~:~:7~'":"':""7"~~~~'~4~9F·0~0~'7::-~7~~~~~~~~~~:;~~1E:5~0r..0~0~'7~~7------------"':'1=-5Il0r°-=0-' ---..:.15=.:llO 3204'0""148.00' ., . . oJV

24~~~~~'" : .. ' :.. ..' '. .. .. :.: .'... '., :: '. :,,:' .. '" -: ." -: ....: .' '. . ~:.. '. ~.:. :~:.' ".:.'::<_/O~;o~: :~>~ ,:... ..-+.' ::-:,: :'~:':~<:.~':' ~ ':'~: .~'.' ~ >;.: ~ 7: :~ '::'~.' .~< .~'.: :~". ~:.d.'~'. :~.: -'.. '.'--:: .-., -.-.. ' ' : ". '.' . .,

... , ',......... ..' . . ..'. . . .' -' ,', -'. '~.' '-',' .. '. '. ' .. ' .: "',:: ' .. ~. ~':;-:". '~.. _ ~ f. :-:--.: .-',.'.~': .~ -.- ~ - ~:.:~:. ~ " .<.' .. :: ".:.. :. :',' .. . . . ' .. ' . " . . . .' .. ". ". . . '. . . . ... ' ... , ..

• .' • • • • • • • " ----.-- • '"'""';""T" • .-. • -.- •. . . .. . ...... . ....:...;. ~ ~ ... . . . . '.' .

.'.~:'.'.:~':'::.l; ~~~~re··_·T'·~·.

......:::.~ ::·~~··::·<i7·::.:;:i.·.::'::~~,·:· <,-,:~ '....

Scale I: 1000 000Q/A 510

Erosional margin of isopached sequence

Top of outcrop of isopached sequence

Inferred depositional margin of isopached sequence

Geological boundary

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

Measured section

100 KILOMETRES!

i

60 MILES

•

----

-50m-}-/OOm-

p

-----!!"",!!!,

Ii

80

40

60

I I

40

20

! t

20IIl!!'''''1

10 0

20 10 0

Areas formerly overlain by isopached sequence

Area of outcrop of isopached sequence

Evergreen Formation alone present~~-~--=-~

~

E:···.;<:·.g

Plate 16 Thickness of Precipice Sandstone and Evergreen Formation

, " SURAT BASiN

t

~undubbero

oMonta

IngleWOO<ia

+

••

,,171

•

18311

pl77

/4}\~O,OO

S°• 40

• •

20+

11102 '"o

•11

•

11 •

. '.,' ... ,

., .. , .

' ...

•

••

•

"

14211 15211

11611 .!4~ I15111 \4;4;'---.} 47

\ ( I~ J! 1'176l32p 113p ~4 12

ROMA 11140 .~122o '-:137"

120p p\20 pl20~3 11134 pll8

120p ,157

...., 91 'Ill "i18 124 11119 14~ 12911 11 •

_ 0 m8 12~ pl45- JI48 ".- •-IO~~ 11103

- pl04 11(85) 100p

-:-,,38

~StG.orq.

~ -.

11

•

..

11119

•

•

•

ODirronbondi

11

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

0801l0n

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

••

•

•

•

•

•

•

•

•

11

•

•

l~ ~~:oo,...--------------=M:U"9~ind;'i~,--------------'--:r...JLi5C~CT----.t:.:::::Z----------l5ioQiy------'"'i& 29°00150.00 151°00' 151°30'29°od 148000' 149°00'

141°00'

14

, :~,-:-_.,.....,:---;'"":"--:--:-:--:-::--""-:-;--:--:-:-:---:--:-:-:-~:-'""""'~~~~-:-::-~~~:::~:~:7~'":"':""7"~~~~'~4~9F·0~0~'7::-~7~~~~~~~~~~:;~~1E:5~0r..0~0~'7~~7------------"':'1=-5Il0r°-=0-' ---..:.15=.:llO 3204'0""148.00' ., . . oJV

24~~~~~'" : .. ' :.. ..' '. .. .. :.: .'... '., :: '. :,,:' .. '" -: ." -: ....: .' '. . ~:.. '. ~.:. :~:.' ".:.'::<_/O~;o~: :~>~ ,:... ..-+.' ::-:,: :'~:':~<:.~':' ~ ':'~: .~'.' ~ >;.: ~ 7: :~ '::'~.' .~< .~'.: :~". ~:.d.'~'. :~.: -'.. '.'--:: .-., -.-.. ' ' : ". '.' . .,

... , ',......... ..' . . ..'. . . .' -' ,', -'. '~.' '-',' .. '. '. ' .. ' .: "',:: ' .. ~. ~':;-:". '~.. _ ~ f. :-:--.: .-',.'.~': .~ -.- ~ - ~:.:~:. ~ " .<.' .. :: ".:.. :. :',' .. . . . ' .. ' . " . . . .' .. ". ". . . '. . . . ... ' ... , ..

• .' • • • • • • • " ----.-- • '"'""';""T" • .-. • -.- •. . . .. . ...... . ....:...;. ~ ~ ... . . . . '.' .

.'.~:'.'.:~':'::.l; ~~~~re··_·T'·~·.

......:::.~ ::·~~··::·<i7·::.:;:i.·.::'::~~,·:· <,-,:~ '....

Scale I: 1000 000Q/A 510

Erosional margin of isopached sequence

Top of outcrop of isopached sequence

Inferred depositional margin of isopached sequence

Geological boundary

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

Measured section

100 KILOMETRES!

i

60 MILES

•

----

-50m-}-/OOm-

p

-----!!"",!!!,

Ii

80

40

60

I I

40

20

! t

20IIl!!'''''1

10 0

20 10 0

Areas formerly overlain by isopached sequence

Area of outcrop of isopached sequence

Evergreen Formation alone present~~-~--=-~

~

E:···.;<:·.g

Plate 16 Thickness of Precipice Sandstone and Evergreen Formation

SURAT BASIN

25°00'

26°00'

151°30'24°30

OMundubbera

oMonta

+

151°00'

••~ ••- ••• 0.

o :"::'::.:~':'.':: •• '

-... ........-:'. . .., ..

oYetmon

•

OCrocow

•36b".

305".

3/6p'

•

150°00'

,0'366

•

".207•

OTOlwood

•

".259

•

•••

p329".266 p "'328

305 /:? 346".296". 300P-"P'~19

289". 327"'259 289"

"'293250' P293

".256

•

•

Mungindi

333".

•

149°00'

344".

-200j215

C/

".376 ".373

".268 ,,298 "'338

290". \314 332". ".393

28" ",293 ,,315 p'328~". ~OO -316~ 378".

" ,,322300 341".

233".

•

•

•

._---150

•

__---200•

•

ODirranband'

•

•

•

o

".226

•

148°00'

•

•

•

•

•

•

•

•

•

'201

•

Mung~300"Mitche

264

•

- __--250-----~

•

•

".172

- ~_- ::-:"0.' •--~~---~---'\- .. - --

--:=-="\----\----"'-----,----1

---~------------:..:I---:-:/---I

Bollon --o _-_-..:/

•

•

:'_.':.'~.' ••~••_°0

• ~' ~.'.' •. . . . . . .. .'. :. ..:':"'>."0 :",,: ': -::: : ;.-:,- ~:.' ~'f,.(-/....

•

•

•

•

•

•

•

••69 •

Morven<4

•

~-~~----- -~

•

•

-------~-o;.:--- ~_-.§Q

•

•29'odL~ J.7ILLL--L-_L~~-h:T---------------~14lc9~00(liO;;o,-------,---------''----"-----'----''11~5000~0)(0'J'-.L---L-L----...L:..=-==::..:::::;L-----~1"'5JcIo~O:;;:Oi',----------:-::-:-!.29°00

147000' 151°30'

27°00'

199

26°00'

147°00'I ., • • • •

24°30 ',:' ".,' ... '. . " .' '.' ' .. .~. ::~. :.~: .~... :~::~. '7-;" :-.-. :.~. '.~. :~:'.:.· . .. '. .... . .... .' . '. ... ...~,' ','_.'.' ,._0..~•.. .....---., .~,'. :_0. .-:,' _'_' '. ~ '.~ ••~•.

". '. '., '.,:.:'.::' ..... : ...• .' °0 • • • • • • • • • • • • .' ." : • '0·· • •

:', ::': ~'::' '.: :::':' :~ :' .:.:, :'.; '.: .: .: ':':' :' .::: :(',7'.<''-: :. '.:.:./:~'" ': :. . ., .·.~ :~ '.:': ~ ;'::'>:.::.'.:,~', :: .:> ::<:' :. :} '.:::.~

Scale 1:1000000Q/A 517

20 10 0 20 40 60 80 100 KI LOM ETRES• , tI ! ! ! " , I

Areas formerly overlain by isopached sequence

t---- ~---------------

~

r::.: .:.. :. :':1

10

Wolloon Coal Measures alone present

Area of outcrop of isopoched sequence

o 20 40 60 MILES

I'''I!UU

------50m--lOOm-

s!

•

Erosional margin of isopached sequence

Top ofoutcrop of isopached sequence

Inferred depositional margin of isopached sequence

Geological boundary

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

Plate 17 Thickness of Hutton Sandstone and Walloon Coal Measures

SURAT BASIN

25°00'

26°00'

151°30'24°30

OMundubbera

oMonta

+

151°00'

••~ ••- ••• 0.

o :"::'::.:~':'.':: •• '

-... ........-:'. . .., ..

oYetmon

•

OCrocow

•36b".

305".

3/6p'

•

150°00'

,0'366

•

".207•

OTOlwood

•

".259

•

•••

p329".266 p "'328

305 /:? 346".296". 300P-"P'~19

289". 327"'259 289"

"'293250' P293

".256

•

•

Mungindi

333".

•

149°00'

344".

-200j215

C/

".376 ".373

".268 ,,298 "'338

290". \314 332". ".393

28" ",293 ,,315 p'328~". ~OO -316~ 378".

" ,,322300 341".

233".

•

•

•

._---150

•

__---200•

•

ODirranband'

•

•

•

o

".226

•

148°00'

•

•

•

•

•

•

•

•

•

'201

•

Mung~300"Mitche

264

•

- __--250-----~

•

•

".172

- ~_- ::-:"0.' •--~~---~---'\- .. - --

--:=-="\----\----"'-----,----1

---~------------:..:I---:-:/---I

Bollon --o _-_-..:/

•

•

:'_.':.'~.' ••~••_°0

• ~' ~.'.' •. . . . . . .. .'. :. ..:':"'>."0 :",,: ': -::: : ;.-:,- ~:.' ~'f,.(-/....

•

•

•

•

•

•

•

••69 •

Morven<4

•

~-~~----- -~

•

•

-------~-o;.:--- ~_-.§Q

•

•29'odL~ J.7ILLL--L-_L~~-h:T---------------~14lc9~00(liO;;o,-------,---------''----"-----'----''11~5000~0)(0'J'-.L---L-L----...L:..=-==::..:::::;L-----~1"'5JcIo~O:;;:Oi',----------:-::-:-!.29°00

147000' 151°30'

27°00'

199

26°00'

147°00'I ., • • • •

24°30 ',:' ".,' ... '. . " .' '.' ' .. .~. ::~. :.~: .~... :~::~. '7-;" :-.-. :.~. '.~. :~:'.:.· . .. '. .... . .... .' . '. ... ...~,' ','_.'.' ,._0..~•.. .....---., .~,'. :_0. .-:,' _'_' '. ~ '.~ ••~•.

". '. '., '.,:.:'.::' ..... : ...• .' °0 • • • • • • • • • • • • .' ." : • '0·· • •

:', ::': ~'::' '.: :::':' :~ :' .:.:, :'.; '.: .: .: ':':' :' .::: :(',7'.<''-: :. '.:.:./:~'" ': :. . ., .·.~ :~ '.:': ~ ;'::'>:.::.'.:,~', :: .:> ::<:' :. :} '.:::.~

Scale 1:1000000Q/A 517

20 10 0 20 40 60 80 100 KI LOM ETRES• , tI ! ! ! " , I

Areas formerly overlain by isopached sequence

t---- ~---------------

~

r::.: .:.. :. :':1

10

Wolloon Coal Measures alone present

Area of outcrop of isopoched sequence

o 20 40 60 MILES

I'''I!UU

------50m--lOOm-

s!

•

Erosional margin of isopached sequence

Top ofoutcrop of isopached sequence

Inferred depositional margin of isopached sequence

Geological boundary

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

Plate 17 Thickness of Hutton Sandstone and Walloon Coal Measures

ss'.:" ( 94 )1:11 4

C'op~ 5

SURAT BASIN

25·00'

OMundubbero

OMonto

+

OCrocow

" .

. .. . ." .

. '.

., ...

. ..

. . . ..

...

. . ... '.. '.' .

.' .. '. . .: ' .

. . . .. .

'. . '. .,

.. '.' ..... '

. . . ., .. . . .' . '. ... ' ' .. . .. ' ...

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Scale 1'1000000 Q/A 511

Pilliga Sandstone replaces a// or part of other sequences

Erosional margin of isopached sequence

Top of outcrop of isopached sequence

Approximate depositional margin of isopached sequence

Geological boundary

Isopachs

100 KI LOM ETRES

60 MILES

Petroleum exploration well

• Wireline-Iogged water bore

) > Palaeocurren t direction

"

80

u...L.l.J U U U

----

-- -----Ioom-J-50m-

p

40

!i

60

20

40, i i'

20

10 0

20 10 0, " ,! '!'! I

Area of outcrop of !sopached interval

Westbourne Formation alone present

Areas formerly over/ain by isopoched sequence

~-----J........ _---

~[: ::: ".'.:..:-:q.' .. ' .' .. :·:: '" .:; : :, .... ':;":

t:~.: .~. :j.' . . ., ..

Plate 18 Thickness of Westbourne Formation and Springbok Sandstone (= Pilliga S51.) interval.

ss'.:" ( 94 )1:11 4

C'op~ 5

SURAT BASIN

25·00'

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Scale 1'1000000 Q/A 511

Pilliga Sandstone replaces a// or part of other sequences

Erosional margin of isopached sequence

Top of outcrop of isopached sequence

Approximate depositional margin of isopached sequence

Geological boundary

Isopachs

100 KI LOM ETRES

60 MILES

Petroleum exploration well

• Wireline-Iogged water bore

) > Palaeocurren t direction

"

80

u...L.l.J U U U

----

-- -----Ioom-J-50m-

p

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20

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10 0

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Area of outcrop of !sopached interval

Westbourne Formation alone present

Areas formerly over/ain by isopoched sequence

~-----J........ _---

~[: ::: ".'.:..:-:q.' .. ' .' .. :·:: '" .:; : :, .... ':;":

t:~.: .~. :j.' . . ., ..

Plate 18 Thickness of Westbourne Formation and Springbok Sandstone (= Pilliga S51.) interval.

SURAT BASINCop~ 5

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Scale I: 1000 000 Q/A 513

20 10 o 20 40 60 80 100 KI LOM ETRES

W,A~I" ~" ' '0 ••"•••

" . ' ' '.....:.: .. : ;.:.."..:.

I' .. "j. . . . .'_.-'' ' ... .

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10 0

Area of outcrop of isopached intervol

Hooray Sandstone sequence replacesGubberamunda Sandstone/Mooga Sandstone sequence

Area formerly overlain by isopached sequence

20 40

,i

60 MILESUU""!!'

-----IOOm-}--50m-

p

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Erosional margin of isopached sequenceTOp of outcrop of isopached sequence

Inferred deposifional margin of isopached sequence

Geological boundary

Isopachs

Petroleum exploration well

Wireline-Iogged water borePalaeocurrent direction

Plate 19 Thickness of Gubberamunda Sandstone/ Mooga Sandstone interval (= Hooray Sst)

SURAT BASINCop~ 5

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.11 V~/:·>·:·.>~.::.· ..:.::':>\:~:: :.~ ::.: :+..;.~ >.: ..:..~ : .'..~..:~ ... : . '. S' .'':'':':::::.::.: '.~ '. :....:::..~:. '_.~ '. :.:.:.': :: : :','::::~~,n~hill~: .' .:. :.~ ....::.: .,d:. '; ':' :' :. -:: •...: ....>~~.~:~;':.~ .;....:..:.:'.:.~.~ :..~:.::~.:/.: :~.:, :~'.:.: :'.':::::':.'>::.:'. ~".~~. ..:~i:·G'.::'7."*:.::..:: ·i.·~·:....:2:..:...~ ..:;.... :,: .:.: ~

". • : ••• '. .' '. • : c'. .' • • '. • ••••• 27°00'".'vI / ...•... : :: : .•.

Y.E305 .' .' ' .. ' . '. ". . .

IS - • if' .' '. '~ ,' : ..~.'t;280 ~ . - .-' ~. -' A..' -.'o .344 / : ,' ... - .... ' .. ' .. ,'. '. '.. ()lJALBY: .::

332./1349 " -)~~ .:~.:~: :..:..:.....~. :.~.:'11 Toro /..=).. .' . . '.. . .: : .....'t1o.. <9 '0// N' -:.: .. : : : .... -: . "::-:.'.

• 335 / /.. ~~/ '-' . -''. -'---' . '-;-;-. '-;-, . ......"· ". V~P'~ IS ,......... ' ... '

• • (290)t?~ : ~::~,,";~:':':....:-.:':~::

384 365 './1 %'..:... ./1: ... ' ....•...., IS .". •••••""",4./1 .11375 ' ' /r.~. .-: . -.. .:: .

383 ' / ,~. .. '. .

,dT4b51 I /,,1:.: .. ? r:.. _ . '-od • _. • _."

415.. °./1415 ./1368 I %§ ..:... :. <-.,'.>: .. :::r", /390) . :........... -'.~ . -. '.';-'1

419 ~05/ Y t: : '.: : ,':. '. :1"'335 /'/ './1(4381 /rt~ : '. -:-'.' . ... .. ~(// ~.: :.... -1 28°00'• •• p(335l e ..~.. ' I

• 1/. .. .. I

· . .

. '. .

. . .

265

. . " ... . . . .' . ". ., .'.• ~". -;..: '0 -'.-' .....:......:. .:..;....... '-: ' •• '.~.: -r-;':~' ~.•L;-••. ' . . . . . . . '. '. '., . . ..· '. .... . . . '. . . '. " . ..,

-=-:-: . .~ '0 • ;-;-. :+'" .-'-' :~. ,: .:.:: :-~ :-~ .. -.:- .~...-'-' -.-. . . . . .' '. . .. ' ... ' . '.' . . . .•-'--.' •.-=-... .• .• . • ..:-. ~. 'o.:.........=.· :...:..-: ,_'-,.'~ • -..-.- , .. , . " " .....::: >. :::.::.. :. . . : .: :: . '0 .: .. : : :: : • ••• d

• •••• • .~. _',0 '0 .'.-' '. -. . -'-' -.-. '--.-. ..-.-' . '-.-. .,--- - ., ..,.:.~::: ':.:>." ':. :::.<..:.~ :'::..::'.;:-..:"<'~'.:~.: ::~: ...S":: ~ .:~:~ ~ /.'

2!5°00' •. : .' . . : .. : : ' . .. ' ..+ '.' .. ::::::';': ~.: .'.: ':.>'; .<::~.: :~". :.'.~.'..::: ~. ">:-~":'.: '.::..::~.'.'7:' ".+

. . .... ," '. .' .' . . . .' . . . .,'.~ ..~ ..~.'.-. -.--.'.7,° -.-, . T"""r .-.-. -.- ••

" .. . ..' .' ...· . '. '.' . " .' . . .....

147°00'24°"'" . '. . .JV ~.-.

Scale I: 1000 000 Q/A 513

20 10 o 20 40 60 80 100 KI LOM ETRES

W,A~I" ~" ' '0 ••"•••

" . ' ' '.....:.: .. : ;.:.."..:.

I' .. "j. . . . .'_.-'' ' ... .

! !I l • , ! , I • ,

10 0

Area of outcrop of isopached intervol

Hooray Sandstone sequence replacesGubberamunda Sandstone/Mooga Sandstone sequence

Area formerly overlain by isopached sequence

20 40

,i

60 MILESUU""!!'

-----IOOm-}--50m-

p

•) ::>

Erosional margin of isopached sequenceTOp of outcrop of isopached sequence

Inferred deposifional margin of isopached sequence

Geological boundary

Isopachs

Petroleum exploration well

Wireline-Iogged water borePalaeocurrent direction

Plate 19 Thickness of Gubberamunda Sandstone/ Mooga Sandstone interval (= Hooray Sst)

SURAT BASIN

26°00'

27°00'

OMundubbero

'-''-L.L-L-L...L...L...J.c....c'--_-;;;15~1oto~O:;-'-------.-1 29°00151°30'

588".

'. ' .. ,

•

6641"

•~ ..

-0 0

o 1~\'l?60

•902

1"958..,.954

p896••

••

•

a/

~I~:::

,,915

900 ".936 1064I"

899". 920 ,,9 7" 981

942"

...

900867p-

•

•

•

•

809•

,,756

•,,701

800 # t>SIGe ge• • •

800

•

,..... ~SOO''£23';:-/ •

I.350+

•

•

•

•

•

•

•

•

•

••

263+.

365."

•

•

. . .. ' .

•

'294

Munglndl • 800' ____29ood~:;--_L__L.1l-L......1~l.--.l._-L.:"-':~~~~:::""_.L._-----------~~":T-:L-_---_~ ---=·~·-;-~;;:;;r.J...-.J'--..lJ

147°00' 149°00'

28°00'

°00' 149°00' 150°00' ,2 4 ~:d"':00~0:'.-'_.,---.-.-.-.-.-.--'--.-:-.---:-.-.-:-.-,..-.~-:-~---:-_-:-:-,1~4..:;8r.:-,·':'. 7.':'.----:-:••7""."':".' -:-.---;-:--:-.""'--~--:.~-:-.-:-.~-:-.-:.-:-.'":.-:-:-~T-:-:..--:-:--:-.-:---;~.~.~'':".:..:-:-:~.----;--:-. -:-:~-:-.:.-;--:-.-:-.~.-:-.:.:-c.:-:-:-.~.7.l'~~:-:'---C-;':-:'';'.:1.r---- ~15~10~0~0-!-------~15~IO32~030

:'.:~: ...-:. .'_.' ....~':'..~:. ~ .'~...~..': :~: :': ~ :..:; ~..... ~ ,,:,::/:: ~:: .:~<::. ~: ::'.: ~ ~~::'::.. :.::.~.;:. :~<:~;".:..:.'.:::.::..:.: .....:.....:....;...:......:.:':' :'.: ...<.~' /~Ui~~.<·:~< ..~·./.' . '.. .'~. ~ ." .' . . '" '.' " . '. . '. . ... " .. . . - . . . . . . . :. .'. ..' .. ' . .' ". . .

- •• '-" -'-' • --.' _." --r' ' •• : •• :.;...... ,-' -' .. : ---!..- ••••_. -. - -' '-. -' ._.. ... , .. . ' ... : '" ..." .. ' , .. . .... . . .'.. '. ., '. '. . ...."...::0: : .. ': ... '. . .. .. . . ' ... '. ., .... ' .. '. '. ..

Scale I: 1000 000Q/A 516

•

!III"',,!!!

100 KILOMETRES

Erosional margin of isapached sequence

Top of outcrop of isopached sequence

Inferred depositional margin of isopached sequence

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

I

60 MILES

80

-500m -}-400m-

~

40

, ,60

,,40

i20

2020 10 0, ! " " ! I! I

10 0

Area of outcrop of isopached sequence

Areas formerly aver/ain by isopached sequence

~E' .... j. .. . . .~<.-.-. :.~.. " ..

I N.T. 1

I OLD.

L

Plate 20 Thickness of non-marine part of Surat Basin sequence (Mooga Sandstone to base of Jurassic)

SURAT BASIN

26°00'

27°00'

OMundubbero

'-''-L.L-L-L...L...L...J.c....c'--_-;;;15~1oto~O:;-'-------.-1 29°00151°30'

588".

'. ' .. ,

•

6641"

•~ ..

-0 0

o 1~\'l?60

•902

1"958..,.954

p896••

••

•

a/

~I~:::

,,915

900 ".936 1064I"

899". 920 ,,9 7" 981

942"

...

900867p-

•

•

•

•

809•

,,756

•,,701

800 # t>SIGe ge• • •

800

•

,..... ~SOO''£23';:-/ •

I.350+

•

•

•

•

•

•

•

•

•

••

263+.

365."

•

•

. . .. ' .

•

'294

Munglndl • 800' ____29ood~:;--_L__L.1l-L......1~l.--.l._-L.:"-':~~~~:::""_.L._-----------~~":T-:L-_---_~ ---=·~·-;-~;;:;;r.J...-.J'--..lJ

147°00' 149°00'

28°00'

°00' 149°00' 150°00' ,2 4 ~:d"':00~0:'.-'_.,---.-.-.-.-.-.--'--.-:-.---:-.-.-:-.-,..-.~-:-~---:-_-:-:-,1~4..:;8r.:-,·':'. 7.':'.----:-:••7""."':".' -:-.---;-:--:-.""'--~--:.~-:-.-:-.~-:-.-:.-:-.'":.-:-:-~T-:-:..--:-:--:-.-:---;~.~.~'':".:..:-:-:~.----;--:-. -:-:~-:-.:.-;--:-.-:-.~.-:-.:.:-c.:-:-:-.~.7.l'~~:-:'---C-;':-:'';'.:1.r---- ~15~10~0~0-!-------~15~IO32~030

:'.:~: ...-:. .'_.' ....~':'..~:. ~ .'~...~..': :~: :': ~ :..:; ~..... ~ ,,:,::/:: ~:: .:~<::. ~: ::'.: ~ ~~::'::.. :.::.~.;:. :~<:~;".:..:.'.:::.::..:.: .....:.....:....;...:......:.:':' :'.: ...<.~' /~Ui~~.<·:~< ..~·./.' . '.. .'~. ~ ." .' . . '" '.' " . '. . '. . ... " .. . . - . . . . . . . :. .'. ..' .. ' . .' ". . .

- •• '-" -'-' • --.' _." --r' ' •• : •• :.;...... ,-' -' .. : ---!..- ••••_. -. - -' '-. -' ._.. ... , .. . ' ... : '" ..." .. ' , .. . .... . . .'.. '. ., '. '. . ...."...::0: : .. ': ... '. . .. .. . . ' ... '. ., .... ' .. '. '. ..

Scale I: 1000 000Q/A 516

•

!III"',,!!!

100 KILOMETRES

Erosional margin of isapached sequence

Top of outcrop of isopached sequence

Inferred depositional margin of isopached sequence

Fault

Isopachs

Petroleum exploration well

Wireline-Iogged water bore

I

60 MILES

80

-500m -}-400m-

~

40

, ,60

,,40

i20

2020 10 0, ! " " ! I! I

10 0

Area of outcrop of isopached sequence

Areas formerly aver/ain by isopached sequence

~E' .... j. .. . . .~<.-.-. :.~.. " ..

I N.T. 1

I OLD.

L

Plate 20 Thickness of non-marine part of Surat Basin sequence (Mooga Sandstone to base of Jurassic)

Cop~ 5

., 4)

SURAT BASIN

, 149°00' 150°00' ° '

14700'0~0~' 1~4~8rO~00~ ........:~-=-------------------~....::..:'--------- ~15~110~0'::- ~15:'.'0~.30'

24°30'r

24030

~Mou~

25°00' + ++ oTheodore

+oMonta

25·00'

27°00'

26°00'

OMundubbera

+

OCrocow

.. '. . '..-:-:": ~ ..~.: .;', ' ..

·M·iles·•• '•• '••••• ' ••• , • :'.

':7: ."~''''1:: :~: :.:, :", '.' :• : •• : : .. :. : • • •••• ~Ch;nchjlla' . : ,If

Jf ---:--. •-.• • 7"'. . -. .,__. . -.- .

.:: ::.:. :.:..:>::.::.:....:i·:~· :.;':-".« ~:...' .' . . . '. '. '. .'. '. '.' . . . .

• • J' •• ' ••• ' •••• ...... •

... .R_ .P~. . _.. •~ .--=.. -'-. • ---L. •. . " . . .

. .. . . . .

•

_---/50-~

_---200-_

. ., ..,.~~~':~:~':': ~._,'. -.:....:. '~.:....:..-' .~' ... "... .'. " .. . . .' .

.~ .:-:- • .L~ •• :..-: • ~. ' ••+

.678

p

p

. .... ..... . ... ' '" .J1 '.:'- •~. ':-=-" • --r : ',_. •. •~ ••

.. ::.~~~7;·::i:T;~•.. 7•..?:.f;::~t;.td-)t.·~YH/ ;:,:...

0722

0 216

p

p

olnjune

... p

"

0725

.734

.-oMitchell

200~ "204

524.

• 229p

•256

~~~OOO/":J

·299

•

'---/50__

Mungolloloo

OBollon

•

•

. . . """'-----"

~:..~ ':~'.:~.. .' .'. .

.' '.'.'. . '.

°

~128

Morven

<4104 167.

253 303••

.357

311

.385

109"

180

156

26°00'

Scale I: 1000000 Q lA 5/5

Areo formerly over/oin by isopoched sequence Erosionol morgin

Inferred depositionol morgin of isopoched sequence

Foult

Isopochs

Petroleum explorotion well

Wireline-Iogged woter bore

100KILOMETFlES

60 MILES

80

°

Illll!!'UU

-som-}-/OOm-

p

40

6040

i20

20, , .10 0

i

10 0

, ,20

W.A

Plate 21 Thickness of marine part of Surat Basin sequence (Rolling Downs Gp + Bungil Fm)

Cop~ 5

., 4)

SURAT BASIN

, 149°00' 150°00' ° '

14700'0~0~' 1~4~8rO~00~ ........:~-=-------------------~....::..:'--------- ~15~110~0'::- ~15:'.'0~.30'

24°30'r

24030

~Mou~

25°00' + ++ oTheodore

+oMonta

25·00'

27°00'

26°00'

OMundubbera

+

OCrocow

.. '. . '..-:-:": ~ ..~.: .;', ' ..

·M·iles·•• '•• '••••• ' ••• , • :'.

':7: ."~''''1:: :~: :.:, :", '.' :• : •• : : .. :. : • • •••• ~Ch;nchjlla' . : ,If

Jf ---:--. •-.• • 7"'. . -. .,__. . -.- .

.:: ::.:. :.:..:>::.::.:....:i·:~· :.;':-".« ~:...' .' . . . '. '. '. .'. '. '.' . . . .

• • J' •• ' ••• ' •••• ...... •

... .R_ .P~. . _.. •~ .--=.. -'-. • ---L. •. . " . . .

. .. . . . .

•

_---/50-~

_---200-_

. ., ..,.~~~':~:~':': ~._,'. -.:....:. '~.:....:..-' .~' ... "... .'. " .. . . .' .

.~ .:-:- • .L~ •• :..-: • ~. ' ••+

.678

p

p

. .... ..... . ... ' '" .J1 '.:'- •~. ':-=-" • --r : ',_. •. •~ ••

.. ::.~~~7;·::i:T;~•.. 7•..?:.f;::~t;.td-)t.·~YH/ ;:,:...

0722

0 216

p

p

olnjune

... p

"

0725

.734

.-oMitchell

200~ "204

524.

• 229p

•256

~~~OOO/":J

·299

•

'---/50__

Mungolloloo

OBollon

•

•

. . . """'-----"

~:..~ ':~'.:~.. .' .'. .

.' '.'.'. . '.

°

~128

Morven

<4104 167.

253 303••

.357

311

.385

109"

180

156

26°00'

Scale I: 1000000 Q lA 5/5

Areo formerly over/oin by isopoched sequence Erosionol morgin

Inferred depositionol morgin of isopoched sequence

Foult

Isopochs

Petroleum explorotion well

Wireline-Iogged woter bore

100KILOMETFlES

60 MILES

80

°

Illll!!'UU

-som-}-/OOm-

p

40

6040

i20

20, , .10 0

i

10 0

, ,20

W.A

Plate 21 Thickness of marine part of Surat Basin sequence (Rolling Downs Gp + Bungil Fm)