geology of the eastern fold belt · mt isa civic centre, 24 june 2008 australian government...

Advances in understanding the Advances in understanding the geology of the Eastern Fold Belt, geology of the Eastern Fold Belt,

Mount Isa regionMount Isa region

Ian WithnallIan Withnallwith contributions from Allan Parsons (GSQ),with contributions from Allan Parsons (GSQ),

Chris Carson & Narelle Neumann (GA) Chris Carson & Narelle Neumann (GA) Mt Isa Civic Centre, 24 June 2008Mt Isa Civic Centre, 24 June 2008

Australian Government

Geoscience Australia

Western

Fold Belt

Murphy Ridge

South Nicholson BasinLawn Hill Platform

Leichhardt R. Fault Trough & Myally ShelfKalkadoon-Leichhardt Block

Wonga Belt (Mary Kathleen Zone) Eastern

Fold Belt

Geological Regions

Outcrop limit of Proterozoic rocks

Seismic lines

Quamby-Malbon & Cloncurry-Selwyn Zones

Corella Fm

Simplified Time-space Diagram for Eastern Fold Belt (after Blake, 1987)

Plum Mtn Gneiss Double Crossing MetsBASEMENT >1900Ma

KALKADOON-LEICHHARDTBLOCK

WONGA

EASTERN FOLD BELT

QUAMBY-MALBON CLONCURRY

COVER SEQUENCE 11875-1850Ma

Leichhardt Volcanics

Kalkadoon Batholith


Argylla Formation

Magna Lynn Metabasalt

Argylla Fm

Soldiers Cap Group

Ballara Qtzt

Marraba Volcs

Mitakoodi Qtzt

Overhang Jspt

Corella Formation

Doherty Fm

Stavely Fm

Answer Slate

Marimo Slate

Kuridala Fm


Wonga Batholith (incl Burstall Granite & related plutons

Deighton Qtzt

White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm

Williams, Naraku, Wimberu Batholiths & related plutons

Roxmere Qtzt

WIDESPREAD EROSION

REGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)

EROSION

EROSION

REGION-WIDE DEFORMATION & METAMORPHISM ~1900MA (BARRAMUNDI OROGENY)

MARY KATHLEEN GROUP

MALBON GROUP

MT ALBERT GROUP

TEWINGA GROUP

~1740Ma

~1550-1500Ma

Some comments on the Blake model for the Eastern Succession

• Based on joint BMR-GSQ mapping from 1968-1978 – no detailed structural studies seriously attempted

• Most boundaries assumed to be stratigraphic (resulting in some confused and conflicting relationships)

• Geochronology largely Rb-Sr and traditional U-Pb dating. SHRIMP dating in infancy and focussed on granites and so-called extrusives (metarhyolite and “tuff”)

• The interpretation of the Corella-Stavely-Doherty rocks appears to be a compromise – Blake believed that there were at least two different ages of these rocks - an idea hotly disputed by Wilson & Derrick

Subsequent research on the Eastern Succession• Detailed structural studies by BMR and university groups 1988-

1992 (Blake & Stewart)• Numerous PhDs, Honours theses and staff research from JCU

through the 1990s• AGSO deep crustal seismic transect - 1994• Structural studies by Monash staff & students in the late 1990s• Continued SHRIMP dating through the 1990s by Page

(BMR/AGSO/GA) and others (e.g. Nuttman & Giles)• Sequence stratigraphic analysis & SHRIMP dating in the

Western Succession by Southgate & others as part of NABRE, AMIRA P552 in late 1990s-2000 provided a temporal framework for correlations with the Eastern Succession

• New work by GA including structural studies by Gibson & SHRIMP dating (including detrital zircons) by Neumann in conjunction with pmd*CRC since 2001

• Revised mapping by GSQ since 2005 (Withnall and Parsons) and SHRIMP dating by Neumann and Carson (GA)

Event chart for the Leichhardt, Calvert & Isa Superbasins

Kalkadoon-Leichhardt Block & Wonga Belt

• Basement of Kalkadoon-Leichhardt Block dated at ca 1865Ma –Kalkadoon Granite & Leichhardt Volcanics essentially coeval

• Leichhardt Volcanics mostly overlain by Magna Lynn Metabasalt – not dated, but generally regarded as part of younger sequence and equivalent in age to the Eastern Creek Volcanics in the Western Succession. However, some evidence for it being basement

• Argylla Formation – felsic volcanics and some sediments; in the Kalkadoon-Leichhardt Block and Wonga Belt dated at 1778Ma

• Overlain unconformably by the Ballara Quartzite, and in turn by the Corella Formation.

• Zircon dating of a tuff in the Ballara Quartzite and crystallisation ages from the Burstall Granite/Revenue Granite indicate that the BallaraQuartzite and Corella Formation were deposited between 1760 & 1740Ma

• Consistent with correlation of the Corella Formation with the QuilalarFormation in Western Succession (max dep age of 1748±3Ma)

Revised Time-space DiagramPlum Mtn Gneiss??


WONGA

EASTERN FOLD BELT



Kalkadoon Batholith

Argylla Formation ~1780Ma


Ballara Qtzt ~1755Ma

Corella Formation


~1845-1875Ma

Burstall~1740Ma

Wonga ~1760-1740Ma


• The Wonga Batholith contains granites ranging from 1760Ma to ~1740Ma

• In the Wonga Belt, mylonitised Argylla Formation cut by undeformed granite constrains a deformation in this area to between 1780 and 1740Ma

• This Wonga Event has been interpreted as an extensional event and may be related to the commencement of deposition of the BallaraQuartzite (and the Quilaler Fm in the west)

• The Burstall Granite and a series of other plutons were emplaced at ~1740Ma

• Constrain the age of the Corella Formation and considered to correspond with the break between the Leichhardt & Calvert Superbasins in the Western Succession. Probably a similar break in the Eastern Succession



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma

WONGA

EXTENSIONWonga

~1740-1760Ma


• The Corella Formation is overlain by the Deighton Quartzite, possibly unconformably. Age of the lower part is not well-constrained (max depage of ~1750Ma) – mafic lavas may correlate with the Fiery Creek Volcanics at ~1710Ma (Big Supersequence in the west)

• Upper part has a imprecise max dep age of ~1690Ma (Prize or Gun Supersequence).

• In the northern part of the Wonga Belt, the Knapdale Quartzite may be a correlative of the Deighton Quartzite

• A sequence of locally carbonaceous scapolitic metasiltstones (formerly mapped as part of the Corella Formation) include the host of the Dugald River deposit - now mapped as Mt Roseby Schist - has a max dep age of ~1685Ma

• Appears to be overlain by the Coocerina Formation and Lady ClayreDolomite

• Succession may be equivalent to the Gun Supersequence in the Western Succession (which includes the Mt Isa Group)



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma

Deighton Qtzt<1690Ma?

White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm

Mt Roseby Schist <1685Ma

WONGA

EXTENSIONWonga

~1740-1760Ma

Dugald RiverDugaldDugald RiverRiver

Cover

Quamby Conglomerate

Naraku Batholith

Metadolerite

Burstall-age granites

Wonga-age granites

Corella Formation

Chumvale Breccia

Overhang Jaspilite

Ballara Qtzt, Mitakoodi Qtzt

Argylla Fm/Bulonga Volcs

Boomara Metamorphics

Tommy Creek Microgranite

Lady Clayre Dolomite

Mt Roseby Schist

Knapdale Quartzite

Coocerina Formation

Tommy Creek area

Porphyritic felsic volcanics

Quartzite conglomerate & sandstone

Marble, calc granofels, minor siltstone & sandstone

Muscovite-garnet schist

Mafic to intermediate lavas & clastics

Undivided (graphitic schist, marble & calc granofels)

Dugald River – Mt Roseby area

Northern Marraba-Quamby area(revised by Withnall 2006-07)

Quamby-Malbon Belt• Oldest rocks are the Double Crossing Metamorphics to

the west of Selwyn and the Boomarra Metamorphics in the Boomarra Horst

• Double Crossing Metamorphics intruded by the Gin Creek Granite, but all other contacts probably tectonic (detachments?)

• Gneiss and migmatite grade westwards and northwards away from the Gin Creek Granite into chloriticmetasiltstone – abundant mafics including possible lavas

• Gin Creek Granite and migmatite leucosomes in the gneiss are both ~1740Ma (Burstall age) indicating a localised metamorphic event at this time

• Detrital spectra hard to interpret – main peak at 1870Ma (Kalkadoon-Leichhardt source) but some grains as young as 1790Ma

• Could be equivalents of Guide or Myally Supersequences• The Boomarra Metamorphics are ~1775Ma (equivalent to

the Argylla Formation) although volcanics are rare -predominantly quartzite and biotite schist intruded by abundant amphibolite (originally mapped as Soldiers Cap Group)

Cloncurry

Cloncurry

Leichhardt Leichhardt River Fault River Fault TroughTrough

Kal

kado

onK

alka

doon

--Le

ichh

ardt

Leic

hhar

dt

QuambyQuamby--MalbonMalbon

WongaWonga

Gin Creek GraniteGin Creek Granite

BoomarraBoomarra MetsMetsDouble Crossing MetsDouble Crossing Mets



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSION

Wonga ~1740-1760Ma

Double Crossing <1790Ma?

Boomarra ~1775Ma

Gin Ck~1740Ma

• Fault-bounded – Pilgrim Fault to west, Overhang Fault on east and possibly thrust under Tommy Creek Block to the north

• Sequence of rocks not easily correlated with those in the Kalkadoon-Leichhardt Block or Wonga Belt –allocthonous?

• Essentially similar volcanics and sediments to the Argylla Formation but 1760Ma (20ma younger) – now referred to as Bulonga Volcanics

• Overlain by thick pile of mafic lavas and some sediments - Marraba Volcanics – no equivalents to west

• Thick sequence of feldspathic sandstone, with some mafic lavas and rare rhyolite (~1755Ma) – correlative with the Ballara Quartzite, but thicker and more feldspathic

• Marraba Volcs & Mitakoodi Qtzt deposited in ~5ma• Overhang Jaspilite – iron and manganese-rich siltstone

and limestone (commonly stromatolitic) – enigmatic siliceous breccias (Chumvale Breccia) - may correlate with the lower part of the Corella Formation, but appears to be overlain by the Corella Formation north of the Mitakoodi Block

Quamby-Malbon Belt -Mitakoodi Block

Cloncurry

Cloncurry

Kal

kado

onK

alka

doon

--Le

ichh

ardt

Leic

hhar

dt


WongaWonga

WongaWonga

Over

hang

Fault

Pilg

rim

Fault

?

Overhang JaspiliteOverhang Jaspilite

MarrabaMarraba VolcanicsVolcanicsMitakoodi QuartziteMitakoodi Quartzite

BulongaBulonga VolcanicsVolcanics

Argylla FormationArgylla Formation



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSIONWonga

~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm

Bulonga Volcs ~1760Ma

Marraba Volcs

Mitakoodi Qtzt ~1755Ma

Overhang Jspt

Mitakoodi Block

Quamby-Malbon Belt – Corella-type rocks

• Most extensively exposed ‘unit’ in the Mount Isa Inlier• Originally mapped as a single unit, the Corella

Formation by Carter et al (1961) and Derrick et al (1977); except for a small area in south mapped as Stavely Formation by Carter et al

• Mainly thin-bedded calcareous metasediments passing into calc-silicate rocks

• Scapolitic in places and may have been deposited in an evaporitic carbonate shelf environment

• Regionally extensive breccias• Coherent stratigraphy in the Kalkadoon-Leichhardt and

Wonga Belts with well defined relationships & readily divisible into 3 members

• Difficult to place stratigraphically in the Quamby-MalbonBelt

– forms a complex of lithologic subdivisions rather than stratigraphic members

– generally more deformed and metamorphosed


• Blake suggested that the Corella Formation probably contained multiple sequences:

– ‘old Corella’ deformed & metamorphosed pre-1740Ma in the Wonga Belt and Kalkadoon-Leichhardt Block

– ‘young Corella’ ca 1600Ma in the Tommy Creek area

– possibly rocks of intermediate age– assigned the rocks in the SE to Doherty

Formation (based on a 1720Ma ‘metarhyolite’ age) and possibly equivalent Stavely Formation

• Blake’s ideas were strongly disputed by Wilson & Derrick

• Subsequently, the Corella Formation was retained for most of the outcrop area, except for the Doherty/Stavely Formations in the SE, with an arbitrary sheet boundary ‘fault’

Cloncurry

Cloncurry

WongaWongaLeichhardt Leichhardt River Fault River Fault TroughTrough

Kal

kado

onK

alka

doon

--Le

ichh

ardt

Leic

hhar

dt

Lawn Lawn HillHill



• The recent work has shown that Blake was largely correct

• Pre-1740Ma Corella Formation is probably restricted to the Kalkadoon-Leichhardt Block, Wonga Belt and northern part of the Quamby-Malbon Belt including the BoomarraHorst

• Corella-type rocks south and east of Cloncurry are probably continuations of Stavely & Doherty Formations

Cloncurry

Cloncurry

WongaWongaLeichhardt Leichhardt River Fault River Fault TroughTrough

Kal

kado

onK

alka

doon

--Le

ichh

ardt

Leic

hhar

dt

Lawn Lawn HillHill


Quamby-Malbon Belt – Corella-type rocks in the Tommy Creek area

• In addition to the Mt Roseby Schist of the Wonga Belt, another younger package has been identified in the Tommy Creek area – the Milo beds

• A heterogeneous succession of calcareous and carbonaceous metasediments and mafic to felsic metavolcanics intruded by high-level microgranite plutons (Tommy Creek Microgranite).

• Dating of the microgranite and detrital zircons from the metasediments bracket the age of the Milo beds to 1665-1660Ma.

• Younger SHRIMP ages on metarhyolite at about 1620Ma are yet to be explained



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSIONWonga

~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma

Mitakoodi BlockTommy Creek

Geology of the Tommy Creek – Corella Park area (mapping by Hill et al 1992 & Withnall, 2006)

Tommy Creek area – ‘Milo beds’

Mitakoodi Quartzite

Cover

Granitoids

Metadolerite

Porphyritic rhyolite

Corella Formation

Chumvale Breccia

Overhang Jaspilite

Quartzite conglomerate & sandstone

Marble, calc granofels, minor siltstone & sandstone

Muscovite-garnet schist

Graphitic schist

Mafic to intermediate lavas & clastics

Tommy Creek Microgranite

Argylla Formation

Undivided (graphitic schist, marble & calc granofels)

RoxmereRoxmere QuartziteQuartzite

Stavely FormationStavely FormationDoherty FormationDoherty Formation

Corella FormationCorella FormationMitakoodi BlockMitakoodi Block

Tommy Creek MicrograniteTommy Creek Microgranite

Soldiers Cap GroupSoldiers Cap Group

Milo bedsMilo beds

KuridalaKuridala FormationFormationAnswer/Answer/MarimoMarimo SlateSlate

Mt Mt RosebyRoseby Schist etcSchist etc

Quamby-Malbon Belt – Corella-type rocks in the Selwyn-Marimo area

• Stavely Formation – sandstone and siltstone, locally calcareous, and impure limestones (superficially like Corella Formation)

• Appears to become more calcareous and more metamorphosed eastwards and may grade into the Doherty Formation, although sharp jumps in grade associated with faults

• Both contain extensive areas of breccia (mechanism uncertain, but probably related to extension and/or fluid overpressuring) – locally intrusive relationships (e.g with Soldiers Cap Group)

• Stavely Formation locally has a gradational relationship with the Roxmere Quartzite (thickening and probably shallowing upwards sequence)

• All other contacts are tectonic• Detrital zircons suggest a max dep age of 1740Ma

(i.e. post-Burstall/Gin Creek igneous/metamorphic event)

• Possible ‘metarhyolite’ in the Doherty Formation is 1725Ma

• Detrital zircons in the Roxmere Quartzite give a 1710Ma max dep age



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSIONWonga

~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

Doherty Fm~1725Ma

LOCALISED METAMORPHISM & DEFORMATION (EXTENSIONAL?) FOLLOWED BY EROSION

Marimo-Stavely






Milo bedsMilo beds



Quamby-Malbon Belt – Answer Slate-Marimo Slate-Kuridala

Formation• Contacts previously inferred to be stratigraphic -

suggesting the Stavely Formation was underlain by the Answer Slate and Kuridala Formation and overlain by the Marimo Slate




• However, most contacts are marked by faults –probably folded thrusts - ferruginised and silicified zones



Corella FormationCorella Formation

Mitakoodi BlockMitakoodi Block

Soldiers Cap GroupSoldiers Cap GroupAnswer/Answer/MarimoMarimo SlateSlate

Revised geology of the Marimo area(Parsons & Withnall, 2006-07)

Marimo

Marimo

Marimo

Stavely

Stavely

Stavely

Roxmere

Quartz Mylonite






Milo bedsMilo beds






• However, most contacts are marked by faults –probably folded thrusts (ferruginised and silicified zones)

• Answer Slate now considered to be equivalent to upper part of the Kuridala Formation and probably the Marimo Slate

• Max dep detrital zircon dates are– Answer Slate ~1660Ma– Marimo Slate ~1655Ma– Kuridala Formation (New Hope Sandstone)

~1675Ma• We intend to raise the Kuridala Formation to

Group status to include an as yet unnamed lower psammite, the New Hope Sandstone and the upper part, now mapped as Answer Slate.



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSION

Wonga ~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

Doherty Fm~1725Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

New Hope Sdst<1675Ma

Answer Slate <1660Ma

Unnamed psammite

Marimo-Stavely

KURIDALAGROUP

Cloncurry Belt – Soldiers Cap Group

• Consist of three units, Llewellyn Creek Formation, Mt NornaQuartzite and the mafic Toole Creek Volcanics

• Originally considered to be basement to Corella/Doherty Formation

• Detrital zircon max dep ages indicate that the Soldiers Cap Group is one of the youngest units in the Eastern Succession

• Max dep ages are ~1660-1680Ma, but a tonalite within a mafic sill that intrudes the Llewellyn Ck Fm is ~1678Ma

• Toole Creek Volcanics have a max dep age of 1658Ma• The data suggests that the Soldiers Cap and Kuridala Groups

are equivalent in age – correlations can be made between:– New Hope Sandstone and Mt Norma Quartzite– Answer Slate (which contains abundant mafic sills and

possibly some basalts) and the Toole Creek Volcanics



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSION

Wonga ~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

Doherty Fm~1725Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma



Unnamed psammite

Marimo-Stavely

Mt Norna Qtzt

Llewellyn ~1680Ma

Toole Ck <1660Ma

KURIDALAGROUP

SOLDIERS CAPGROUP

Isan Orogeny

• Deformation and metamorphism intermittently over almost 100ma – at least four recognised events

• Earliest high-grade metamorphic event in the Isan Orogeny in the Eastern Succession constrained by dates on metamorphic monazite, titanite and zircon rims to between ~1600 and 1585Ma – some monazite suggest it may have started even earlier (~1620Ma)

• Monazite ages and zircon overgrowths give a variety of younger ages, including 1570 and 1520Ma

• Voluminous I and A-type magmatism over ca 55my from about 1550 to 1495Ma associated with the Williams Batholith and related plutons. Many of these plutons, including some of the youngest are deformed



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSIONWonga

~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma

Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

Doherty Fm~1725Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma



Unnamed psammite

Mt Norna Qtzt

Llewellyn ~1680Ma

Toole Ck _1660Ma

Williams, Naraku, Wimberu Batholiths & related plutons 1550-1495MaREGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)

Event chart for the Leichhardt, Calvert & Isa Superbasins

Correlations with the Western Succession

• Pre-1740 Ma rocks in the Kalkadoon-Leichhardt Block and Wonga Belt correlate reasonably well with the Western Succession– Argylla Formation and Magna Lynn Metabasalt are equivalent to

the Myally Supersequence– The Ballara Quartzite and Corella Formation are equivalent to the

Quilaler Supersequence• Deighton and Knapdale Quartzite are difficult to place, and possibly

correlate with the Big or Prize Supersequences or both –unconformities are suggested by conglomerates in the DeightonQuartzite

• The Mt Roseby Schist, Coocerina Fm & Lady Clayre Dolomite can be equated to the Gun Supersequence and may be deeper water equivalents of the Paradise Creek Formation

Correlations with the Western Succession• In the Quamby-Malbon Belt, correlations are less certain• The Boomara Metamorphics and Double Crossing Metamorphics are

probably correlatives of the Myally Supersequence• The Bulonga Volcanics and Marraba Volcanics have no equivalents

elsewhere – correlate with a break in the west – the felsic volcanics may be extrusive equivalents of the older Wonga granites

• The Mitakoodi Quartzite and Overhang jaspilite can be equated with the Quilaler Supersequence

• The Stavely & Doherty Formations and Roxmere Quartzite are difficult to place because of lack of data – max dep ages are inconclusive (although post-1740Ma) and rocks could partly correlate with depositional breaks in the west when the shoreline could have been east of the Wonga Belt– Stavely-Doherty show an apparent eastward increase in carbonate,

possibly related to a siliciclastic facies passing into a carbonate platform

Correlations with the Western Succession

• The lower part of the Soldiers Cap and Kuridala Groups may have been deposited during the break between the Prize and Gun Supersequences (during emplacement of the Sybella Batholith)

• However, the upper part of the Soldiers Cap and Kuridala Groups can be correlated with the Gun Supersequence and can be interpreted as the basinal facies equivalent to the platform facies of the Western Succession

• The voluminous tholeiitic basalts and dolerite sills in these groups may be related to a transition from rift to drift when the Georgetown Province may have separated from Mount Isa



WONGA

EASTERN FOLD BELT



Kalkadoon Batholith




Corella Formation


~1845-1875Ma

Burstall~1740Ma


White Blow Fm

Knapdale Qtzt

Coocerina Fm

Lady Clayre Dolm


WONGA

EXTENSIONWonga

~1740-1760Ma


Boomarra ~1775Ma

Gin Ck~1740Ma

Corella Fm


Marraba Volcs


Overhang Jspt

Milo beds <1660Ma

Tommy Ck ~1653Ma

Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma

Doherty Fm~1725Ma


Stavely Fm<1740Ma

Roxmere Qtzt<1710Ma



Unnamed psammite

Mt Norna Qtzt

Llewellyn ~1680Ma

Toole Ck _1660Ma

Williams, Naraku, Wimberu Batholiths & related plutons 1550-1495MaREGION-WIDE DEFORMATION & METAMORPHISM 1620-1550MA (ISAN OROGENY)

Myally

Quilalar

Gun

Big &/or Prize?

LEIC

HH

AR

DT

SUPE

RB

ASI

NIS

A

SBC

ALV

ERT

SB

geology of the eastern fold belt · mt isa civic centre, 24 june 2008 australian government...

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