Clay Minerals, Alteration Terry’s pH-Temperature Table Kaylene Camuti.pdf · Clay Minerals, Alteration & Terry’s pH-Temperature Table Kaylene Camuti ... Services Jane Harvey,

Lantana Exploration Lantana Exploration -- TLS Oct 2008TLS Oct 2008

Clay Minerals, AlterationClay Minerals, Alteration& &

Terry’s pHTerry’s pH--Temperature TableTemperature Table

Kaylene CamutiLantana Exploration Pty Ltd

Additional data provided by:Greg Corbett - Corbett Geological Services

Jane Harvey, Juli Hugenholtz & Doug Young - ActivEX Limited


Clay Minerals, AlterationClay Minerals, Alteration& &

Terry’s pHTerry’s pH--Temperature TableTemperature Table

Kaylene CamutiLantana Exploration Pty Ltd

Additional data provided by:Greg Corbett - Corbett Geological Services

Jane Harvey, Juli Hugenholtz & Doug Young - ActivEX Limited


Skarn

Potassic

Propylitic

Outer Propylitic

Phyllic

Argillic

Advanced Argillic

Common Alteration Mineralogy in Hydrothermal SystemsCommon Alteration Mineralogy in Hydrothermal Systems

Terry Leach 1995


Temperature Temperature -- K activity DiagramK activity Diagram500

400

300

200

1001 2 3 4 5

log(aK+/aH+)

100 MPaQuartz Present

K-FeldsparMuscovite

Andalusite

Pyrophyllite

Kaolinite

(from Inoue, 1995, after Sverjensky et al., 1991)

Dickite at higher temps

Illite at lower temps



OutlineOutline

• Why identify alteration minerals & assemblages?

• Characteristics of alteration minerals & assemblages illustrated in the pH-temperature table

• Using the table to interpret alteration minerals.


Why identify alteration minerals?Why identify alteration minerals?

• The chemistry and structure of alteration minerals are a response to their conditions of formation – so the minerals and mineral assemblages provide information on hydrothermal conditions.

• The minerals typically occur in zones that reflect changing conditions of formation.

• The recognition of alteration mineral zoning can help identify hydrothermal fluid channelways and may provide vectors to mineralisation.

Lantana Exploration Lantana Exploration -- TLS Oct 2008TLS Oct 2008 Corbett & Leach

Low Low SulphidationSulphidation SystemsSystems


chlorite-rich smectite-rich illite-rich quartz-alunite richkaolinite-rich

vuggymineralisedquartz

unalteredquartzlatite

smectite-chloritezone

illite-kaolinite

zone

quartz-alunitezone

(adapted from Steven & Ratte, 1960, in Hayba et al., 1985)

High High SulphidationSulphidation Alteration Alteration -- SummitvilleSummitville


CharacteristicCharacteristicAlteration Minerals & AssemblagesAlteration Minerals & Assemblages

• Some alteration minerals or alteration assemblages are characteristic of particular temperature & fluid pH conditions.

• The pH – temperature table has been subdivided into alteration types with diagnostic mineral assemblages.

Lantana Exploration Lantana Exploration -- TLS Oct 2008TLS Oct 2008 Terry Leach 1995

ArgillicArgillic

pH ~ 4 pH ~ 4 -- 66

PhyllicPhyllic

pH ~ 5 pH ~ 5 -- 66

AdvancedAdvanced

ArgillicArgillic

pH < 4pH < 4

PropyliticPropylitic

pH ~ 6 +pH ~ 6 +

PotassicPotassic

pH ~ 7 +pH ~ 7 +


Silicate Alteration Minerals Silicate Alteration Minerals -- characteristicscharacteristics

kaolin mineralskaolin minerals

Al, Al, SiSi, OH, OH

HH22OO

pyrophyllitepyrophyllite

Al, Al, SiSi, OH, OH

andalusiteandalusite

Al Al SiSi

silica mineralssilica minerals

SiSi +/+/-- HH22OO

poorly crystallinepoorly crystalline

quartzquartz

SiSi

crystallinecrystalline

illiteillite –– smectitesmectite

K, Al, Mg, Fe, K, Al, Mg, Fe, SiSi, OH, OH

HH22OO

muscovitemuscovite

K, Al, Mg, Fe, K, Al, Mg, Fe, SiSi, OH, OH

chlorite mineralschlorite minerals

Fe, Mg, Al, Fe, Mg, Al, SiSi, OH, OH

HH22OO

epidoteepidote + amphibole + amphibole mineralsminerals

Ca, Fe, Mg, Al, Ca, Fe, Mg, Al, SiSi, OH, OH

biotitebiotite

K, Fe, Mg, Al, K, Fe, Mg, Al, SiSi, OH, OH

pyroxenepyroxene

Ca, Mg, Fe, Ca, Mg, Fe, SiSi

increasing fluid pHincreasing fluid pH

incr

easi

ng te

mpe

ratu

rein

crea

sing

tem

pera

ture


Using the table to interpret alteration assemblages Using the table to interpret alteration assemblages in mineral explorationin mineral exploration


XRD Summary Results XRD Summary Results –– HS System HS System -- tabletable

minorDiaspore

trace?trace- minortrace?trace?Feldspars

tracetrace?Rutile

minorTourmaline

minor-majorminorminortraceminorminorPyrite

dommajortrace –minordomdommajor-domdomQuartz

minor-(major)trace?Alunite Group

majorChlorite

dommajorML Illite-Smect

majormajorHydrated Illite

majortrace-minor?majorweak trace?majormajorIllite

traceminortraceweak trace

?Kaolin Group

majormajor-domPyrophyllite

26252423222120Minerals


PIMA PIMA –– list of alteration mineralslist of alteration minerals

SmectiteFine-gr'd Porphyry? Pale grey, fine-grained, hard, with hematite

fracturesOutcropBM1004A

KaoliniteAluniteOutcrop at top (v rocky), pale alteration with yell-brown coatingOutcropBM1003C

KaoliniteAluniteOutcrop at top (v rocky), pale alteration with yell-brown coatingOutcropBM1003B

KaolinitePyrophylliteFine-gr'd Porphyry? Pink-Red alteration (hard)OutcropBM1002B

PyrophylliteAluniteKaoliniteFine-gr'd Porphyry? Red alteration (Fine-grained, hard)OutcropBM1002A

KaoliniteAluniteQtz Porphyry? Very red, fine-grained siliceousOutcropBM1001E

TopazPyrophylliteKaoliniteSilicified Qtz porphyry? Pinky-grey with diss hematite spotsOutcropBM1001D

KaoliniteSericitePale green altd fragmental(?) volcanicQuarryDB006C

(trace Sericite)KaolinitePale clay altd volcanic(?) with local ferruginous stainQuarryDB006B

KaoliniteSericiteVery fine-gr'd porphyry, pink QuarryDB006A

SericiteFelspar Porphyry, east of silica zone, pink with sericiteOutcropDB005B

KaoliniteSericiteFelspar Porphyry, east of silica zone, pink with sericiteOutcropDB005A

KaoliniteSericitePink porphyry, sericite altered OutcropDB004C

KaoliniteSericitePink porphyry, sericite altered OutcropDB004A

(trace Topaz)KaoliniteDickiteVery pale, clay altered OutcropDB003C

TopazKaoliniteDickiteVery pale clay altered OutcropDB003B

KaoliniteDickiteVery pale clay altered OutcropDB003A

KaoliniteDickiteFine-gr'd porphyry? very pale alteration, sparse hematite microfracturesOutcropDB001B

DickiteKaoliniteFine gr'd porphyry? pale brown alterationOutcropDB001A

Mineral 3Mineral 2Mineral 1DescriptionSampleTypeSample ID


Drill Log Drill Log -- descriptivedescriptive

Pervasive dark green Chlor alteration.sp160.2153.2

Strong clay alteration of primary KFs. Local disseminated pink secondary KFs.

sd89.383.8

Strong Chl and Ser - texturally destructiveip83.583

Pervasive strong Chl replacing KFs & Hblendesd40.839.7

Weakly disseminated KFs alteration with locally developed moderate Chl. wd32.624.7

Weakly disseminated KFs alteration with locally developed moderate Chl. md24.721.5

DescriptionIntStyleToFrom


XRD Summary Results XRD Summary Results –– HS SystemHS System

minorDiaspore


tracetrace?Rutile

minorTourmaline




majorChlorite





?Kaolin Group


26252423222120Minerals


2020



minorDiaspore


tracetrace?Rutile

minorTourmaline




majorChlorite





?Kaolin Group


26252423222120Minerals


2020

2121



minorDiaspore


tracetrace?Rutile

minorTourmaline




majorChlorite





?Kaolin Group


26252423222120Minerals


2020

21212222


2020

21212222

23232626

?


chlorite-rich smectite-rich illite-rich quartz-alunite richkaolinite-rich

vuggymineralisedquartz

unalteredquartzlatite

smectite-chloritezone

illite-kaolinite

zone

quartz-alunitezone

(adapted from Steven & Ratte, 1960, in Hayba et al., 1985)

High High SulphidationSulphidation Alteration Alteration -- SummitvilleSummitville






BlairmoreBlairmore –– DemonbangaDemonbangaAlteration Minerals from PIMA study Alunite

Pyrophyllite

Dickite

Kaolinite

Diaspore

Topaz

Sericite

Illite-Smectite

Smectite

The minerals occur in a variety of assemblages.


pyrophyllitepyrophyllite--alunitealunite


kaolinitekaolinite--pyrophyllitepyrophyllite--topaztopaz


pyrophyllitepyrophyllite--kaolinitekaolinite--diasporediaspore


dickitedickite--kaolinitekaolinite--topaztopaz


sericitesericite--kaolinitekaolinite


montmorillonitemontmorillonite--kaolinitekaolinite


dickitedickite alunitealunite


11 22 33 44 55 66 77 88





11

2a2a2b2b

2c2c

33

1. Porphyry high sulphidation systems

2. Structural & lithologicalhigh sulphidationsystems

2a. Silica Core

2b. Deep peripheral zones

2c. Shallow peripheral zones

3. Descending cool acid sulphate fluids

Documents

Clay Minerals, Alteration Terry’s pH-Temperature Table Kaylene Camuti.pdf · Clay Minerals, Alteration & Terry’s pH-Temperature Table Kaylene Camuti ... Services Jane Harvey,