gold silver agus nur aurora gold company.pdf

CODES: AMIRA P588 July 2001 MeetingCODES: AMIRA P588 July 2001 Meeting Confidential to SponsorsConfidential to Sponsors

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EpithermalEpithermal Gold-Silver Deposits: Geochemical and Gold-Silver Deposits: Geochemical andIsotopic Vectors to Target Major Deposits - P588.Isotopic Vectors to Target Major Deposits - P588.

Case Study:Case Study: Permata Permata--Batu BadindingBatu Badinding--HulubaiHulubai Au-Ag Au-AgLode Systems, MtLode Systems, Mt Muro Muro,, Kalimantan Kalimantan, Indonesia, Indonesia

AndrewAndrew Wurst WurstCentreCentre for Ore Deposit Research for Ore Deposit Research


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Indonesian Archipelago GeologyIndonesian Archipelago Geology


3MtMt Muro Muro Regional Geology Regional Geology


4PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Regional Structure Regional Structure


5PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Geology Geology

ll TheThe Permata Permata footwall and footwall and hangingwallhangingwall;;sequences were deposited on the slopes ofsequences were deposited on the slopes ofanan andesitic stratovolcano andesitic stratovolcano

PermataPermata Batu BadindingBatu Badinding--HulubaiHulubai

l Hulubai hangingwall; shallowsubaqueous, sediments, hyaloclastitesbreccias, lappili tuff

ll HulubaiHulubai footwall is footwall is corellatedcorellated with withPermataPermata footwall and is deposited on the footwall and is deposited on theslopes of an slopes of an andesitic stratovolcanoandesitic stratovolcano

ll Batu Badinding hangingwallBatu Badinding hangingwall; shallow; shallowsubaqueoussubaqueous. sediments,. sediments, lappili lappili tuff, tuff,amygdaloidalamygdaloidal basalt basalt

ll Batu BadindingBatu Badinding footwall; sub-aerial to footwall; sub-aerial tosub-aqueous, deposited in a valley typesub-aqueous, deposited in a valley typeenvironmentenvironment


6Regional StructureRegional Structure


7Permata-Batu Badinding-Hulubai Regional StructurePermata-Batu Badinding-Hulubai Regional Structure


8Riedel’sRiedel’s Clay Model Experiment Clay Model Experiment


9PermataPermata--Batu BadindingBatu Badinding--Hulubai Hulubai KinematicsKinematics


10Summary ofSummary of Permata Permata--Batu BadindingBatu Badinding--HulubaiHulubaiStructural DevelopmentStructural Development

••PBH represents a series ofPBH represents a series of dilational dilational structures developed structures developedin basin fill volcanic cover over a competent basement.in basin fill volcanic cover over a competent basement.

••Progressive movement on basement structures has givenProgressive movement on basement structures has givenrise to the progressive development ofrise to the progressive development of dilatant dilatant cover coverstructures.structures.

••Is this reflected in the evolution of theIs this reflected in the evolution of the hydrothermal hydrothermalsystem?system?


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PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Paragenesis Vein Paragenesis

StageStage 1Stage 1:Stage 1: Jasperoid Jasperoid Veins Veins

ll EmplacedEmplaced in 20° openings in 20° openingsdipping to the westdipping to the west

ll BrecciasBreccias and fine and finegrained,grained, colloform colloform and andcrustiformcrustiform textures textures

ll Quartz-hematite veinQuartz-hematite veinmineralogymineralogy

ll Intensely (Intensely (illiteillite--adulariaadularia))alteredaltered wallrock wallrock


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Stage 2: Chalcedony VeinsStage 2: Chalcedony Veins StageStage 2

ll EmplacedEmplaced in 165° - 210° in 165° - 210°openings dipping to theopenings dipping to thewestwest

ll Fine grained,Fine grained, breccias breccias,,crustiformcrustiform and andcolloformcolloform textures textures

ll Quartz-(pyrite) veinQuartz-(pyrite) veinmineralogymineralogy

ll Intensely (Intensely (illiteillite--adulariaadularia--pyrite) alteredpyrite) altered wallrock wallrock


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Stage 3Stage 3Stage 3: Ore VeinsStage 3: Ore Veins

ll EmplacedEmplaced in 165° - 210° in 165° - 210°openings dipping to theopenings dipping to thewest and eastwest and east

ll Fine grained, Fine grained, crustiformcrustiform,,colloformcolloform and cockade and cockadetexturestextures

ll Quartz-Quartz-sulphosaltsulphosalt--sulphidesulphide-precious metal--precious metal-adulariaadularia vein mineralogy vein mineralogy



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PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Paragenesis Vein ParagenesisStage 4Stage 4Stage 4: Ore VeinsStage 4: Ore Veins

ll EmplacedEmplaced in 165° - 210° in 165° - 210°openings dipping to theopenings dipping to thewest and eastwest and east

ll Fine grained.,Fine grained., crustiform crustiform,,colloformcolloform and cockade and cockadetexturestextures

ll Quartz-Quartz-sulphosaltsulphosalt--sulphidesulphide-precious metals--precious metals-adulariaadularia vein mineralogy vein mineralogy(increased base metals)(increased base metals)



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PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Paragenesis Vein ParagenesisStage 5Stage 5Stage 5: Amethyst VeinsStage 5: Amethyst Veins

ll EmplacedEmplaced in 165° - 210 ° in 165° - 210 °and 120° openings and 120° openings infillinginfillingcavitiescavities

ll Coarse grained openCoarse grained opendogtoothdogtooth,, crustiform crustiform,,colloformcolloform and cockade and cockadetexturestextures

ll Amethyst and clear-whiteAmethyst and clear-whitequartz vein mineralogyquartz vein mineralogy

ll Weakly alteredWeakly altered(background chlorite-(background chlorite-epidoteepidote-pyrite) altered-pyrite) alteredwallrockwallrock


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PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Paragenesis Vein ParagenesisStage 6Stage 6Stage 6: Carbonate VeinsStage 6: Carbonate Veins

ll EmplacedEmplaced in 165° - 210 ° in 165° - 210 °and 60°-85° openingsand 60°-85° openings

ll Fine grained, Fine grained, crustiformcrustiform,,colloformcolloform and cockade and cockadetexturestextures

ll Deep Calcite and shallowDeep Calcite and shallowmanganoanmanganoan calcite veins calcite veins

ll Shallow veins have weaklyShallow veins have weakly(background chlorite-(background chlorite-epidoteepidote) altered ) altered wallrockwallrock

ll Deep veins associated withDeep veins associated withintense (Mg chlorite)intense (Mg chlorite)altered altered wallrockwallrock


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PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Mineralogy Vein Mineralogy

Vein Mineral ParagenesisVein Mineral Paragenesis


18PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N 12 000N

Cross section across line 12 000N metal, mineral andCross section across line 12 000N metal, mineral andalteration distribution.alteration distribution.


19PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Geology 12 000N: Geology


20PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Zinc 12 000N: Zinc


21PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Lead 12 000N: Lead


22PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Copper 12 000N: Copper


23PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Silver 12 000N: Silver


24PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Gold 12 000N: Gold


25PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: 12 000N: Metallogeny Metallogeny

AuAuGeologyGeology

CuCu PbPb ZnZn

AgAg


26PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Carbonate 12 000N: Carbonate


27Origin of Massive Calcite Veins, Golden CrossOrigin of Massive Calcite Veins, Golden Cross


28PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Alteration 12 000N: Alteration


29PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai 12 000N: Fluid Flow 12 000N: Fluid Flow

GeologyGeology

AuAuZnZnCarbonateCarbonate

AlterationAlteration


30Boiling EffectsBoiling Effects


31Buchanan Model (1981)Buchanan Model (1981)


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ConclusionsConclusions

•• A constantly evolving system in four dimensions; A constantly evolving system in four dimensions;structurally and structurally and hydrothermallyhydrothermally

•• Volcanics Volcanics and sediments deposited in basins developed and sediments deposited in basins developedover basement shear structuresover basement shear structures

•• Vein paragenesis reflects the geochemical and Vein paragenesis reflects the geochemical andstructural evolution of thestructural evolution of the hydrothermal hydrothermal system system

•• Progressive movement on basement structures facilitatedProgressive movement on basement structures facilitatedthe development of the development of ReidelReidel style tensional veins style tensional veins


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•• One main fluid One main fluid upflow upflow structure with a large fluid recharge structure with a large fluid rechargeareaarea

•• Late carbonate represents draw down of fluid due to Late carbonate represents draw down of fluid due toventuriventuri effects and/or the waning of the effects and/or the waning of the hydrothermalhydrothermalsystemsystem

ConclusionsConclusions

••Progressive opening of the structure focuses fluid flow andProgressive opening of the structure focuses fluid flow andmaintainsmaintains the open conduit the open conduit

•• Recharge and collapse areas are represented by Recharge and collapse areas are represented by phengitephengiteand carbonate alterationand carbonate alteration


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•• Vein paragenesis gives an insight into the maturity of theVein paragenesis gives an insight into the maturity of thehydrothermalhydrothermal system system

ImplicationsImplications

•• Transverse shear structures in basement can give rise to dilatory Transverse shear structures in basement can give rise to dilatorystructures in cover sequencesstructures in cover sequences

•• Basin areas had a significant amount of water associated with them Basin areas had a significant amount of water associated with them

•• Areas of carbonate veining and alteration represent the footprint Areas of carbonate veining and alteration represent the footprintrecharge area of arecharge area of a hydrothermal hydrothermal system system

•• Fluid is drawn along and alters more permeable or reactive layers Fluid is drawn along and alters more permeable or reactive layersproviding a vector to major providing a vector to major upflowupflow structures structures


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Future workFuture work

•• Oxygen and carbon isotopes on vein stages at Oxygen and carbon isotopes on vein stages at Kerikil Kerikil and PBH and PBH- Carbonate veins- Carbonate veins- Quartz veins- Quartz veins

(fluid inclusions will provide temperature constraints)(fluid inclusions will provide temperature constraints)

•• Oxygen isotopes on alteration assemblages at Oxygen isotopes on alteration assemblages at Kerikil Kerikil and PBH and PBH

•• PBH andPBH and Kerikil Kerikil wallrock lithogeochemistrywallrock lithogeochemistry

•• Mineral chemistry of alteration minerals such as chlorite andMineral chemistry of alteration minerals such as chlorite andcarbonatecarbonate

•• Possible fluid flow and chemical modeling Possible fluid flow and chemical modeling


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AcknowledgementsAcknowledgements


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ExtrasExtras


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V e i n S t a g e S T A G E 1 S T A G E 2 S T A G E 3 S T A G E 4 S T A G E 5 S T A G E 6 T y p e J a s p e r o i d -

q u a r t z C r y p t o -c r y s t a l i n e q u a r t z

P r e c i o u s m e t a l- s u l p h o s a l t - c r y p t o -c r y s t a l i n e q u a r t z

P r e c i o u s m e t a l-b a s e m e t a l- S u l p h o s a l t - q u a r t z

A m e t h y s t - q u a r t z C a l c i t e - q u a r t z

A g e E a r l i e s t ⇒⇒ D e c r e a s i n g A g e ⇒⇒ S t r u c t u r a l O r i e n t a t i o n

N N E N N E -S S E N N E - S S E N N E - S S E a n d N W N N E - S S W a n d N W N N E , S S W a n d N E

M o v e m e n t I n i t i a l o p e n i n g o f t i g h t R o a n d R 1 f r a c t u r e s ⇒⇒ P r o g r e s s i v e s t r a i n a n d o p e n i n g o f t e n s i o n a l f r a c t u r e s ⇒⇒ L a t e d o m i n o f a u l t s ,

V e i n T e x t u r e s B r e c c i a t e d v e i n w a l l r o c k s . V e i n s e x h i b i t f i n e i n t e r n a l b a n d i n g a n d c r u s t i f o r m g r o w t h

B r e c c i a t e d v e i n w a l l r o c k s a n d e a r l i e r x p t o c r y s t a l i n e v e i n s V e i n s e x h i b i t f i n e i n t e r n a l b a n d i n g a n d c r u s t i f o r m , c o l l o f o r m a n d c o c k a d e g r o w t h

V e i n s e x h i b i t f i n e i n t e r n a l b a n d i n g o f q u a r t z a n d s u l p h o s a l t s a n d c r u s t i f o r m , c o l l o f o r m a n d c o c k a d e g r o w t h

V e i n s e x h i b i t f i n e i n t e r n a l b a n d i n g o f q u a r t z a n d s u l p h o s a l t s l a t e c o a r s e g r a i n e d b a s e m e t a l s a n d c r u s t i f o r m , c o l l o f o r m a n d c o c k a d e g r o w t h

L a t e c o a r s e g r a i n e d d o g s t o o t h a m e t h y s t e x h i b i t i n g c r u s t i f o r m , c o l l o f o r m a n d c o c k a d e g r o w t h

I n f i l l i n g e a r l i e r v u g g y s p a c e s i n a m e t h y s t e e x h i b i t i n g c r u s t i f o r m g r o w t h

V e i n S t y l e T i g h t , f i n e t o m a s s i v e c r y s t a l l i n e ⇒⇒ I n c r e a s e d g r a i n s i z e a n d d i l a t i o n ⇒⇒ O p e n , c o a r s e g r a i n e d c r y s t a l i n e

Q u a r t z G r o w t h

F i n e c r y s t a l i n e q u a r t z w i t h h e a m a t i t e d u s t i n g

F i n e c r o s s h a t c h e d q u a r t z c r y s t a l s g r a i n s i z e v a r y i n g w i t h l i g h t a n d d a r k b a n d s .

P l u m o s e a n d g h o s t t e x t u r e s

P l u m o s e a n d g h o s t t e x t u r e s , i n c r e a s i n g l y c o a r s e r g r a i n e d w i t h g r o w t h i n c l u s i o n t r a i l s

D o g s t o o t h q u a r t z w i t h P l u m o s e a n d g h o s t t e x t u r e s , c o a r s e g r a i n e d w i t h g r o w t h i n c l u s i o n t r a i l s

D o g s t o o t h q u a r t z w i t h P l u m o s e a n d g h o s t t e x t u r e s , c o a r s e g r a i n e d w i t h g r o w t h i n c l u s i o n t r a i l s

M i n e r a l o g y Q u a r t z -h e a m a t i t e

Q u a r t z - p y r i t e Q u a r t z , p y r i t e , A g t e l l u r i d e s , A g s u l p h o s a l t -e l e c t r u m -s p h a l e r i t e - g a l e n a -c h a l c o p y r i t e

Q u a r t z , p y r i t e , A g s u l p h o s a l t , e l e c t r u m , s p h a l e r i t e , g a l e n a , c h a l c o p y r i t e

A m e t h y s t i n e a n d b u c k y w h i t e q u a r t z

C a l c i t e a n d c l e a r w h i t e q u a r t z

A l t e r a t i o n I n t e n s e l y a r g i l l i c a l l y a l t e r e d w a l l r o c k s

I n t e n s e l y a r g il l i c a l l y a l t e r e d w a l l r o c k s

I n t e n s e l y a r g i l l i c a l l y a l t e r e d w a l l r o c k s

I n t e n s e l y a r g i l l i c a l l y a l t e r e d w a l l r o c k s

M o d e r a t e l y t o w e a k l y p r o p y l i t c a l l y a l t e r e d w a l l r o c k s

W e a k l y a l t e r e d w a l l r o c k s .

F l u i d F l o w H i g h r a t e o f t u r b u l e n t h y d r o t h e r m a l u p f l o w , f a s t d e p o s i t i o n

H i g h r a t e o f t u r b u l e n t h y d r o t h e r m a l u p f l o w , f a s t d e p o s i t i o n

H i g h r a t e o f t u r b u l e n t h y d r o t h e r m a l u p f l o w , f a s t d e p o s i t i o n

H i g h a n d m o d e r a t e r a t e o f h y d r o t h e r m a l u p f l o w a n d f a s t a n d s l o w d e p o s i t i o n

M o d e r a t e r a t e o f h y d r o t h e r m a l u p f l o w a n d s l o w d e p o s i t i o n

C o l l a p s e o f h y d r o t h e r m a l s y s t e m w i t h s l o w d e p o s i t i o n

E n v i r o n m e n t T i g h t h i g h T i g h t h i g h R h y t h m i c o p e n i n g R h y t h m i c o p e n i n g O p e n l o w t e m p , O p e n l o w

PermataPermata--Batu BadindingBatu Badinding--HulubaiHulubai Vein Evolution Vein Evolution

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