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AY 998
F L
PO
Australian Mineral Industries Research Association LimitedACN 004 448 266
Studies of VHMS-related
alteration: geochemical and
mineralogical vectors to ore
P439
~"CODES SRC
AY 998
Australian Mineral Industries Research Association LimitedACN 004 448 266
Studies of VHMS-related
alteration: geochemical and
mineralogical vectors to ore
P439
~..CODES SRC
Studies of VHMS-related alteration:geochemical and mineralogical vectors to ore
EXECUTIVE
SUMMARY
AMIRAlARC project P439
Volume 1, Final ReportMay 1998
009'
CODES SRC
Studies of VHMS-related alteration:geochemical and mineralogical vectors to ore
EXECUTIVE
SUMMARY
AMIRAlARC project P439
Volume 1, Final ReportMay 1998
009'
CODES SRC
ii
Centre for Ore Deposit Research,School of Earth Sciences,University of Tasmania,GPO Box 252-79,Hobart, Tasmania,
Australia 7001
http://www.geol.utas.edu.au/codes
another Pongratz Production 1998
ii
Centre for Ore Deposit Research,School of Earth Sciences,University of Tasmania,GPO Box 252-79,Hobart, Tasmania,
Australia 7001
http://www.geol.utas.edu.au/codes
another Pongratz Production 1998
iii
Contents
Introduction 1
Summary of geochemical and mineralogical vectors to ore, based on the seven case studies in P439
- Ross Large, Bruce GemmelI and Walter Herrmann 5
Alteration halo model for the Rosebery VHMS deposit, western Tasmania
- Ross Large, Rod Alien, Mike Blake and WaIter Herrmann 13
,Alteration model for the HelIyer VHMS deposit, western Tasmania
- J. Bruce GemmelI and RusselI Fulton 17
Mt Julia-Henty gold mine: Summary of alteration study - Tim Callaghan 21
Alteration halo model for the Zone 96 volcanogenic gold deposit, Henty gold mine,
western Tasmania - Jason Beckton 27
Alteration zonation and geochemical dispersion at the Western Tharsis deposit, Mt LyelI,
Tasmania: a summary - David Huston and Julianne Kamprad 29
Alteration halo of the Thalanga VHMS deposit, north Queensland - Holger Paulick 33
Alteration halo model for the Highway-Reward sub-seafloor replacement deposit,
Mount Windsor Subprovince, Queensland - Mark G. Doyle 39
Alteration case study of the Gossan Hill VHMS deposit - Robina Sharpe and Bruce GemmelI 43
Carbonate alteration at the Rosebery mine: The relationships between alteration texture,
paragenesis, chemistry of carbonate minerals, and distance to ore - Rodney L. Alien,
Michael Blake and Ross R. Large 47
A molar element ratio analysis of lithogeochemical samples from the footwall andesite,
Hellyer VHMS district, Tasmania, Australia - Clifford R. Stanley and J. Bruce GemmelI 53
Chlorite alteration associated with syn-volcanic granites and Cu-Au mineralisation:
A pilot study along the Jukes Road - Bill Wyman 57
cont.
CODES: AMIRA/ ARC Project P439Studies of VHMS-related alteration: geochemical and
mineralogical vectors to ore. May 1998~CODES SRC
iii
Contents
Introduction 1
Summary of geochemical and mineralogical vectors to ore, based on the seven case studies in P439
- Ross Large, Bruce GemmelI and Walter Herrmann 5
Alteration halo model for the Rosebery VHMS deposit, western Tasmania
- Ross Large, Rod Alien, Mike Blake and WaIter Herrmann 13
,Alteration model for the HelIyer VHMS deposit, western Tasmania
- J. Bruce GemmelI and RusselI Fulton 17
Mt Julia-Henty gold mine: Summary of alteration study - Tim Callaghan 21
Alteration halo model for the Zone 96 volcanogenic gold deposit, Henty gold mine,
western Tasmania - Jason Beckton 27
Alteration zonation and geochemical dispersion at the Western Tharsis deposit, Mt LyelI,
Tasmania: a summary - David Huston and Julianne Kamprad 29
Alteration halo of the Thalanga VHMS deposit, north Queensland - Holger Paulick 33
Alteration halo model for the Highway-Reward sub-seafloor replacement deposit,
Mount Windsor Subprovince, Queensland - Mark G. Doyle 39
Alteration case study of the Gossan Hill VHMS deposit - Robina Sharpe and Bruce GemmelI 43
Carbonate alteration at the Rosebery mine: The relationships between alteration texture,
paragenesis, chemistry of carbonate minerals, and distance to ore - Rodney L. Alien,
Michael Blake and Ross R. Large 47
A molar element ratio analysis of lithogeochemical samples from the footwall andesite,
Hellyer VHMS district, Tasmania, Australia - Clifford R. Stanley and J. Bruce GemmelI 53
Chlorite alteration associated with syn-volcanic granites and Cu-Au mineralisation:
A pilot study along the Jukes Road - Bill Wyman 57
cont.
CODES: AMIRA/ ARC Project P439Studies of VHMS-related alteration: geochemical and
mineralogical vectors to ore. May 1998~CODES SRC
iv
Use of immobile elements and chemostratigraphy to determine precursor volcanics- Walter Herrmann 61
Development and use of the alteration box plot - Ross Large 63
Application of PIMA and FTIR spectometry to VHMS alteration studies - Walter Herrmann,
Michael Blake, Mark Doyle, David Huston and Julianne Kamprad 65
P439 geochemical whole-rock and mineral database - Michael D. Blake 69
Discrimination of diagenetic, hydrothermal and metamorphic alteration
- Rodney L. Allen, Cathryn C. Gifkins, Ross Large and WaIter Herrmann 73
Geochemical modelling of low temperature (5° to 150°C) seawater-andesite interaction:
Implications for regional alteration assemblages in VHMS districts- Stephen B. Bodon and David R. Cooke 79
Application of ironstone geochemistry to exploration for VHMS deposits in the
Mt Windsor Volcanic Belt - Garry Davidson : 81
Volcanic facies and alteration - J McPhie 85
Alteration in different glassy volcanics with emphasis on early diagenetic alteration;
a case study from the Mount Black Volcanics - Cathryn C Gifkins 91
Influence of volcanic fades on hydrothermal and diagenetic alteration: Evidence from the
Highway-Reward deposit, Mount Windsor Subprovince, Queensland - Mark G. Doyle 95
Bibliography 101
iv
Use of immobile elements and chemostratigraphy to determine precursor volcanics- Walter Herrmann 61
Development and use of the alteration box plot - Ross Large 63
Application of PIMA and FTIR spectometry to VHMS alteration studies - Walter Herrmann,
Michael Blake, Mark Doyle, David Huston and Julianne Kamprad 65
P439 geochemical whole-rock and mineral database - Michael D. Blake 69
Discrimination of diagenetic, hydrothermal and metamorphic alteration
- Rodney L. Allen, Cathryn C. Gifkins, Ross Large and WaIter Herrmann 73
Geochemical modelling of low temperature (5° to 150°C) seawater-andesite interaction:
Implications for regional alteration assemblages in VHMS districts- Stephen B. Bodon and David R. Cooke 79
Application of ironstone geochemistry to exploration for VHMS deposits in the
Mt Windsor Volcanic Belt - Garry Davidson : 81
Volcanic facies and alteration - J McPhie 85
Alteration in different glassy volcanics with emphasis on early diagenetic alteration;
a case study from the Mount Black Volcanics - Cathryn C Gifkins 91
Influence of volcanic fades on hydrothermal and diagenetic alteration: Evidence from the
Highway-Reward deposit, Mount Windsor Subprovince, Queensland - Mark G. Doyle 95
Bibliography 101
Introduction
Project objectives P439
The five project objectives of P439 as outlined in theoriginal research proposal are:
• To characterise the mineralogy and geochemistryfor the various styles of hydrothermal alteration
throughout the Mount Read Volcanics (MRV) andthe Mount Windsor Volcanics (MWV). This will
be based on mapping supported by whole-rockand trace element geochemistry, mineral
chemistry, REE and stable isotope geochemistry.
• To determine the relationship between geochemical alteration patterns and sub-volcanicintrusions that are coeval with VHMS formation.
• To undertake case studies of alteration halos relatedto specific VHMS deposits with particularemphasis on hangingwall alteration, and therelationship between alteration patterns andvolcanic fades.
• To develop a set of vectors towards ore based onthe regional studies and ore deposit specific studiesthat can be applied in the exploration for VHMS
deposits in submarine volcanic sequences throughout Australia. The vector matrix will includewhole-rock, trace element, mineral chemistry, REE,isotope and volcanic fades factors.
• To produce a book on "Alteration mineralogy,geochemistry and textures in volcanics related toVHMS deposits" as a follow-up to the successfulpublication by CODES of "Volcanic Textures".
At the first progress meeting (April 1995), and in
subsequent meetings, a number of sponsors emphasised the importance of including studies onmineral chemistry in both the regional and deposit
case studies. In response to this request the work onmineral chemistry was expanded in the latter part of
the project at the expense of some of the plannedisotQpic and REE research.
Research framework
This project involved a multidisdplinary approachutilising studies in volcanic fades analysis, volcanic
petrology and geochemistry, with alteration andmineralisation to develop models for the composition,
style and extent of alteration throughout submarine
volcanic environment hosting VHMS deposits. The
venn diagram below outlines the relationshipsbetween the different modules of the project.
Petrographyandgeochemist
Alteration andmineralisation
CODES; AMIRA/ARC Project P439 Studies of VHM5-related alteration: geochemical and
mineralogical vectors to ore. May 199800•CODES SRC
Introduction
Project objectives P439
The five project objectives of P439 as outlined in theoriginal research proposal are:
• To characterise the mineralogy and geochemistryfor the various styles of hydrothermal alteration
throughout the Mount Read Volcanics (MRV) andthe Mount Windsor Volcanics (MWV). This will
be based on mapping supported by whole-rockand trace element geochemistry, mineral
chemistry, REE and stable isotope geochemistry.
• To determine the relationship between geochemical alteration patterns and sub-volcanicintrusions that are coeval with VHMS formation.
• To undertake case studies of alteration halos relatedto specific VHMS deposits with particularemphasis on hangingwall alteration, and therelationship between alteration patterns andvolcanic fades.
• To develop a set of vectors towards ore based onthe regional studies and ore deposit specific studiesthat can be applied in the exploration for VHMS
deposits in submarine volcanic sequences throughout Australia. The vector matrix will includewhole-rock, trace element, mineral chemistry, REE,isotope and volcanic fades factors.
• To produce a book on "Alteration mineralogy,geochemistry and textures in volcanics related toVHMS deposits" as a follow-up to the successfulpublication by CODES of "Volcanic Textures".
At the first progress meeting (April 1995), and in
subsequent meetings, a number of sponsors emphasised the importance of including studies onmineral chemistry in both the regional and deposit
case studies. In response to this request the work onmineral chemistry was expanded in the latter part of
the project at the expense of some of the plannedisotQpic and REE research.
Research framework
This project involved a multidisdplinary approachutilising studies in volcanic fades analysis, volcanic
petrology and geochemistry, with alteration andmineralisation to develop models for the composition,
style and extent of alteration throughout submarine
volcanic environment hosting VHMS deposits. The
venn diagram below outlines the relationshipsbetween the different modules of the project.
Petrographyandgeochemist
Alteration andmineralisation
CODES; AMIRA/ARC Project P439 Studies of VHM5-related alteration: geochemical and
mineralogical vectors to ore. May 199800•CODES SRC
The research was undertaken at the regional scaleand the deposit scale in order to develop criteriauseful for both regional exploration and mine scaleexploration. The regional studies concentrated in theMt Read Volcanics with lesser work in the MtWindsor Volcanics. The emphasis was (a) todetermine the relationship between volcanic fadesand alteration, and (b) to develop criteria todistinguish amongst diagenetic alteration, metamorphic-related alteration and hydrothermalalteration (VHMS related). The deposit case studiesincluded research at Mt Lyell, Hellyer, Rosebery andHenty in the Mt Read Volcanics; Thalanga andHighway Reward in the Mt Windsor Volcanics andGossan Hill in the Murcmson Volcanics (WA). Theemphasis in the deposit studies was (a) to map outalteration assemblages and zonation, (b) relatealteration mineralogy and geochemistry, (c) investigate trace element halos, and (d) to study variationsin mineral chemistry and their relationship toalteration zonation. Because considerable researchhas been published about VHMS footwall alteration,then the focus of the P439 deposit studies was onhangingwall alteration. Our ultimate objective wasto combine the regional and deposit scale studies tocharacterise hydrothermal alteration and develop
vectors to ore.
Achievements of project
This project has made a major advance in ourunderstanding and interpretation of alteration insubmarine volcanics related to VHMS hydrothermalsystems. The prindple achievements listed in theorder that they appear in this final report are givenbelow.
1. Detailed halo alteration models have beendeveloped for the following seven VHMSdeposits; Hellyer, Rosebery, Henty, WesternTharsis, Thalanga, Highway-Reward and GossanHill.
Each model includes a set of criteria and vectorsthat are useful for regional and mine scaleexploration. This is the first time that a set ofVHMS alteration models has been presented
which include volcanic fades, chemostratigraphy, lithogeochemistry, alteration zonation,halo geochemistry, mineral chemistry andvectors to ore.
2. The deposit case study reports (Volume 2)include a series of Alteration Data Sheets whichcombine geological, geochemical, textural andmineralogical information, including photos onthe one page, to allow comparison of the maincharacteristics of alteration. This format wasdeveloped during the project and emphasisesthe advantages of a multidisdplinary approachin the study of alteration.
3. An in-depth evaluation of the application ofPIMA to alteration studies around VHMSdeposits has been completed with emphasis onthe spectral characteristics of muscovite and theirrelationship to VHMS deposits (Western Tharsis,Roseb~ry and Highway-Reward). This workcombines PIMA spectral data, with micro-probemineral chemistry, whole-rock chemistry andthin section petrography. No study of this typehas been previously completed for VHMSdeposits.
4. A set of criteria have been developed to distinguish diagenetic alteration, metamorphicalteration and hydrothermal (VHMS-related)alteration in submarine volcanics. The criteriacombine studies on volcanic fades, volcanictextures, petrology and lithogeochemistry.
5. An alteration box plot has been developed andtested, which enables comparison of alterationmineralogy with geochemistry to provide aclassification of alteration fades related to VHMSsystems.
6. A Pearce element ratio analysis of altered andunaltered rock compositions within the andesiticfootwall to the Hellyer VHMS deposit wasrevealed several new concepts regarding thehydrothermal alteration. In addition, newinnovative exploration vectors have beendeveloped.
The research was undertaken at the regional scaleand the deposit scale in order to develop criteriauseful for both regional exploration and mine scaleexploration. The regional studies concentrated in theMt Read Volcanics with lesser work in the MtWindsor Volcanics. The emphasis was (a) todetermine the relationship between volcanic fadesand alteration, and (b) to develop criteria todistinguish amongst diagenetic alteration, metamorphic-related alteration and hydrothermalalteration (VHMS related). The deposit case studiesincluded research at Mt Lyell, Hellyer, Rosebery andHenty in the Mt Read Volcanics; Thalanga andHighway Reward in the Mt Windsor Volcanics andGossan Hill in the Murcmson Volcanics (WA). Theemphasis in the deposit studies was (a) to map outalteration assemblages and zonation, (b) relatealteration mineralogy and geochemistry, (c) investigate trace element halos, and (d) to study variationsin mineral chemistry and their relationship toalteration zonation. Because considerable researchhas been published about VHMS footwall alteration,then the focus of the P439 deposit studies was onhangingwall alteration. Our ultimate objective wasto combine the regional and deposit scale studies tocharacterise hydrothermal alteration and develop
vectors to ore.
Achievements of project
This project has made a major advance in ourunderstanding and interpretation of alteration insubmarine volcanics related to VHMS hydrothermalsystems. The prindple achievements listed in theorder that they appear in this final report are givenbelow.
1. Detailed halo alteration models have beendeveloped for the following seven VHMSdeposits; Hellyer, Rosebery, Henty, WesternTharsis, Thalanga, Highway-Reward and GossanHill.
Each model includes a set of criteria and vectorsthat are useful for regional and mine scaleexploration. This is the first time that a set ofVHMS alteration models has been presented
which include volcanic fades, chemostratigraphy, lithogeochemistry, alteration zonation,halo geochemistry, mineral chemistry andvectors to ore.
2. The deposit case study reports (Volume 2)include a series of Alteration Data Sheets whichcombine geological, geochemical, textural andmineralogical information, including photos onthe one page, to allow comparison of the maincharacteristics of alteration. This format wasdeveloped during the project and emphasisesthe advantages of a multidisdplinary approachin the study of alteration.
3. An in-depth evaluation of the application ofPIMA to alteration studies around VHMSdeposits has been completed with emphasis onthe spectral characteristics of muscovite and theirrelationship to VHMS deposits (Western Tharsis,Roseb~ry and Highway-Reward). This workcombines PIMA spectral data, with micro-probemineral chemistry, whole-rock chemistry andthin section petrography. No study of this typehas been previously completed for VHMSdeposits.
4. A set of criteria have been developed to distinguish diagenetic alteration, metamorphicalteration and hydrothermal (VHMS-related)alteration in submarine volcanics. The criteriacombine studies on volcanic fades, volcanictextures, petrology and lithogeochemistry.
5. An alteration box plot has been developed andtested, which enables comparison of alterationmineralogy with geochemistry to provide aclassification of alteration fades related to VHMSsystems.
6. A Pearce element ratio analysis of altered andunaltered rock compositions within the andesiticfootwall to the Hellyer VHMS deposit wasrevealed several new concepts regarding thehydrothermal alteration. In addition, newinnovative exploration vectors have beendeveloped.
7. Preliminary thermodynamic modelling of lowtemperature seawater-volcanic rock interactionhas been completed, and demonstrates the value
of this approach in determining the temperatureand fluid chemical controls on diagenetic and
hydrothermal alteration.
8. A data base of whole rock and trace element
geochemistry for samples from the Mt ReadVolcanics, Mt Windsor Volcanics and the seven
ore deposit case studies has been compiled. Thedata base includes 1730 rock analyses (thisproject), 2845 MRV rock analyses from othersources (Tas Uui, MRT and Pasminco), and 1020microprobe mineral analyses from the depositstudies. The data base is provided to all sponsorson a compact disc located in the back envelope
of this report (Volume 1).
9. A study of ironstone geochemistry, includingREE and isotopes has shown the application ofthis approach to exploration in the Mt Windsor
Volcanics.
10. Controls on both diagenetic alteration and
hydrothermal alteration by volcanic fades andvolcanic textures has been evaluated and shown
to be critically important, especially at the
diagenetic stage. This work includes regionalstudies especially the Mt Black Volcanics, and
focussed research at Rosebery and HighwayReward.
This report
The final Report for P439 is divided into four volumes:
Vol. 1: Executive SummaryVol. 2: Ore Deposit case studies and related
researchVol. 3: Regional studies and volcanic facies
controls.Vol. 4: Field meeting guide, Mt Windsor Volcanic
Belt.
Acknowledgements
This project has been supported by the followingcompanies and organisations:
Aberfoyle Resources Limited
Copper Mines of Tasmania
Denehurst Limited
Mineral Resources Tasmania
Normandy Exploration
Pasminco ExplorationQueensland Metals Corporation Ltd
RGC ExplorationRio Tinto Exploration
On behalf of the research team I would like tothank all the company representatives, collaboratorsand AMIRA for their support and scientificinteraction throughout this three year program. In
par~cularwe are indebted to those companies thatprovided access to their deposits for the case studies:RGC, Pasminco, Murchison Zinc, Copper Mines ofTasmania and Aberfoyle.
This project would not have been possible withoutthe very significant contributions by a number of
dedicated and hardworking postgraduate students:Catherine Gifkins, Robina Sharpe, Mark Doyle,
Holger Paulick, Bill Wyman and Russell Fulton.Thanks also for the tireless work of Mike Blake in
organising the alteration data sheets, and to Nilar
Hlaing for printing and collating the papers. As usual
June Pongratz has done a great job in coordinatingand producing this final report.
We hope that the final outcome of this project is
the discovery of a new VHMS deposit in the nearfuture.
U~__"'4
Ross R. LargeDirectorCentre for Ore Deposit Research.
CODES: AMIRA/ARC Project P439Studies of VHMS-related alteration: geochernical and
mineralogical vectors to ore. May 199800•CODES SRC
7. Preliminary thermodynamic modelling of lowtemperature seawater-volcanic rock interactionhas been completed, and demonstrates the value
of this approach in determining the temperatureand fluid chemical controls on diagenetic and
hydrothermal alteration.
8. A data base of whole rock and trace element
geochemistry for samples from the Mt ReadVolcanics, Mt Windsor Volcanics and the seven
ore deposit case studies has been compiled. Thedata base includes 1730 rock analyses (thisproject), 2845 MRV rock analyses from othersources (Tas Uui, MRT and Pasminco), and 1020microprobe mineral analyses from the depositstudies. The data base is provided to all sponsorson a compact disc located in the back envelope
of this report (Volume 1).
9. A study of ironstone geochemistry, includingREE and isotopes has shown the application ofthis approach to exploration in the Mt Windsor
Volcanics.
10. Controls on both diagenetic alteration and
hydrothermal alteration by volcanic fades andvolcanic textures has been evaluated and shown
to be critically important, especially at the
diagenetic stage. This work includes regionalstudies especially the Mt Black Volcanics, and
focussed research at Rosebery and HighwayReward.
This report
The final Report for P439 is divided into four volumes:
Vol. 1: Executive SummaryVol. 2: Ore Deposit case studies and related
researchVol. 3: Regional studies and volcanic facies
controls.Vol. 4: Field meeting guide, Mt Windsor Volcanic
Belt.
Acknowledgements
This project has been supported by the followingcompanies and organisations:
Aberfoyle Resources Limited
Copper Mines of Tasmania
Denehurst Limited
Mineral Resources Tasmania
Normandy Exploration
Pasminco ExplorationQueensland Metals Corporation Ltd
RGC ExplorationRio Tinto Exploration
On behalf of the research team I would like tothank all the company representatives, collaboratorsand AMIRA for their support and scientificinteraction throughout this three year program. In
par~cularwe are indebted to those companies thatprovided access to their deposits for the case studies:RGC, Pasminco, Murchison Zinc, Copper Mines ofTasmania and Aberfoyle.
This project would not have been possible withoutthe very significant contributions by a number of
dedicated and hardworking postgraduate students:Catherine Gifkins, Robina Sharpe, Mark Doyle,
Holger Paulick, Bill Wyman and Russell Fulton.Thanks also for the tireless work of Mike Blake in
organising the alteration data sheets, and to Nilar
Hlaing for printing and collating the papers. As usual
June Pongratz has done a great job in coordinatingand producing this final report.
We hope that the final outcome of this project is
the discovery of a new VHMS deposit in the nearfuture.
U~__"'4
Ross R. LargeDirectorCentre for Ore Deposit Research.
CODES: AMIRA/ARC Project P439Studies of VHMS-related alteration: geochernical and
mineralogical vectors to ore. May 199800•CODES SRC
