A color enhancement of an ultraviolet photograph of the spectrum of the upper atmosphere of the Earth and geo-corona. The bright horizontal line is far ultraviolet emission of hydrogen extending 40,000 miles either side of the Earth. UV camera was operated by Astronaut John W. Young on the Apollo 16 lunar landing mission

Mineral Systems in the Mineral Systems in the TasmanidesTasmanides: : The Global PerspectiveThe Global Perspective

Bedding

20cm

CleavageWoodlawn Rock

Track of the talk:Track of the talk:

••Record in the mantle for Record in the mantle for hydridic fluid fluxhydridic fluid flux

••Track record of Earth degassing Track record of Earth degassing as recorded by Earthas recorded by Earth’’s oceans s oceans

/sedimentary record/sedimentary record

••Implications for giant mineral Implications for giant mineral resources Archaean, resources Archaean,

ProterozpocProterozpoc & & TasmanidesTasmanides

Graphite / Diamondnot stable

-15 -10 -5 0 5

0

100

200

300

400

500

600

700

Dep

th ( k

m)

ΔQFMlog fO2

SiCstable

COHfluidonly

max graphite / diam

ond stability limit

"Q"IF

(fo90)IW

graphite / diamondstable

a ski

= 10

-5

= 10

-3=

10-2

- S. African peridotite (Woodland & Koch, 2003)

FMQ

IW

“Q”IF

2Fe2+3Fe3+2Si3O4(gt) = 4Fe2SiO4(ol) + 2FeSiO3(px) + O2; Gudmundsson & Wood,1995 Ed Mikucki, 2006

CO2

H2O

CH4

H2

0.0

0.2

0.4

0.6

0.8

1.0

-15 -10 -5 0 5

Xi

XH2OXCO2XCH4XCOXH2

IW "Q"IF(fo90)

ΔQFMlog fO2

z = 646.8 kmT = 1553oCP = 220.5 Kbar

diamond / graphitestable

SiC stable COH

fluid

-15 -10 -5 0 5

0

100

200

300

400

500

600

700

Dep

th (k

m)

ΔQFMlog fO2

SiCstable

COHfluidonly

max graphite / diam

ond stability limit

"Q"IF

(fo90)IW

graphite / diamondstable

a ski

= 10

-5

= 10

-3=

10-2

Di Pierro et al, 2003

Si FeSi2Fe3Si7CaSi2Si2N2OFe-Ti silicides REE silicates

Hydrogen flux Hydrogen flux from Earthfrom Earth’’s cores core

metasomatisingmantle wedge

HH22O Domain O Domain

plate

COCO22 ±± HH22O O ±± melts melts Domain Domain

HH2 2 ±± CHCH44 Domain Domain

10km10km

100 km100 km

1000 km1000 kmHH2 2 fluxflux

sealseal

sealseal

Nature of gas flux through Earth history?Nature of gas flux through Earth history?It is possible to identify:It is possible to identify:

epochs of high rates of H2 diffusionepochs of high rates of H2 diffusion

epochs of epochs of advectiveadvective loss of reduced, CH4loss of reduced, CH4--rich gases rich gases

epochs of epochs of advectiveadvective loss of oxidized CO2loss of oxidized CO2--rich gases rich gases

These epochs relate to the These epochs relate to the flux of hydridic fluids flux of hydridic fluids from the Earthfrom the Earth’’s core.s core.

Hydridic fluid flux drive Hydridic fluid flux drive redoxredox--relate processes relate processes EarthEarth’’s mantle, crust, s mantle, crust, hydrosherehydroshere, atmosphere, atmosphere

Williams & Hemley (2001);Okuchi T (1997); Larin (1993)

FeH

Fe e.g. mass extinction& metallogenesis …….

Paleo - Proterozoic Neo -Meso -

COCO22atmos atmos COCO22sw + Hsw + H22 CHCH44 + H+ H22O: O: methanogenesismethanogenesis

CHCH44 fixed as organic matter/methane clathrate fixed as organic matter/methane clathrate

Major Epochs of H2 DiffusionMajor Epochs of H2 Diffusion

Defined by positive deviations in Defined by positive deviations in δδ1313C seawater C seawater

δδ1212C C CHCH4 4 and COand CO22sw enriched in sw enriched in δδ1313CC

δ13 C

Sea

wate

r(‰

)

Ga1.52.5 2.0 1.0 0.5 0

12

0

-4

8

4

Sources of data Holland (2005)Melezhik et al. (2005)COCO22type type methanogensmethanogens: H: H22 flux fuels flux fuels methanogenesismethanogenesis

Paleoproterozoic Neo-Meso- Phanerozoic

δ13 C

Sea

wate

r(‰

)

Ga

Sources of informationMelezhik et al. (2005), Holland (2005), Kaufman et al (1997), Veizer et al. (1999), Saltzman & Young (2005)

1.52.5 2.0 1.0 0.5 0

12

0

-4

8

4

Overall draw down in greenhouse gases leads to Earth coolingOverall draw down in greenhouse gases leads to Earth cooling: Kaufman et al. (1997) : Kaufman et al. (1997)

Ice Ages

Positive Positive δδ1313C C excursions commonly predate cooling/glaciationexcursions commonly predate cooling/glaciationNeoproterozoicNeoproterozoic & & PhanerozoicPhanerozoic

Ice Ages & Epochs of H2 DiffusionIce Ages & Epochs of H2 DiffusionPaleoproterozoic Neo-Meso- Phanerozoic

HH22 flux fuels flux fuels methanogenesismethanogenesis & reduction of greenhouse gases & reduction of greenhouse gases

Mass Extinction 440Ma

Sources of informationMelezhik et al. (2005), Canfield (2005), Holland (2005) & references therein

0.1

0.3

10

0

-10

0

10

4.0 3.0 2.0 1.0 0.53.5 2.5 1.5

δ13 C

swδ3

3 Ssw

Band

ed I

ron

Form

atio

n

CO2 fluxCH4 flux H2 flux

Epochs of CHEpochs of CH44 & CO& CO22 Flux Flux

Define high CODefine high CO22 ±± SOSO2 2 flux from distribution of banded iron formation flux from distribution of banded iron formation

Defined high CHDefined high CH44 ±± HH2 2 ±± HH22SS by negative deviations in by negative deviations in δδ1313C seawater; C seawater; δδ3333Sanomalies; global anoxiaSanomalies; global anoxia

Ga

Metal transport with deep Metal transport with deep –– Earth Earth hydridic fluidshydridic fluids

FeH

Fe

AuCr, Ni PGEsPb, ZnU

H2S, N, CHalogensNa, Li

3000 km

Complexes of halides, chlorides, amines,carbonyls, cyanides

Williams & Hemley (2001); Okuchi T (1997); Larin (1993)

Cr, Ni, PGEs, Au

Pb, Zn; Cu

Bushveld; Sudbury; Komatiitic Ni

800-1000 ºC; Magmatic Conditions

100- 200 ºC; Sedimentary/basin environment

500-600ºCHydrous

Anhydrous Challenger; formed with melt

Porphyry Cu deposits

Deep –fluidsInfluencepH, redox, salinitytemp

Broken Hill (BHTs)

Au

Most Au depositsPb-Zn sedimentary deposits

Magmatic deposits: Silicate melts act as trap medium for metals in hydridic fluids; not transport medium

BushveldBushveld ComplexComplex

ReefsReefs

PotholesPotholes

Sink not source ???

Hydridic fluids (metals)

Q: What is the mechanism Q: What is the mechanism of advection of COof advection of CO22±±CHCH44through the crust through the crust

A: Transient, A: Transient, DeepDeep--lithosphericlithospheric blasts blasts of gas, of gas,

or or VerneshotsVerneshots

J. Phipps Morgan et al, EPSL 217 (2004) 263-284

Sufficient energy to produce shocked quartz & shattercones

VerneshotsVerneshots in major in major mineral provincesmineral provinces

VredefortVredefortDomeDome

Johannesburg

Witwatersrand BasinKlerksdorp

CarswellCarswell structurestructure

Archaean

Proterozoic

Sudbury “Impact”

CrossCross--Arc StructuresArc Structures& Lachlan Tectonic & Lachlan Tectonic ZoneZone

PathwaysPathwaysfrom the from the mantle ???mantle ???

Squire &Miller, 2003

Bass Canyon

Cross-Arc Structures

200km

Mt Isa

11001100

35003500

Tracking pathways of deepTracking pathways of deep--EarthEarth

Fluids: Mt Fluids: Mt IsaIsa Cu OrebodiesCu Orebodies

NS

-25.00

-15.00

-5.00

5.00

100 120 140 160 180 200 220 240

Depth (m)

δ13C

Positive deviation δ13C– H2 reducing CO2 DDH

Graphite

Carbonate

Ccpore zone

pyriteHW

poFW

H2 Flux

CO2 + 4H2 = CH4+ 2H2O

Clues from Clues from ArchaeanArchaeanAu & Ni? Au & Ni? depositsdeposits

Geological Geological map of the map of the St. Ives gold St. Ives gold campcampYilgarnYilgarnWAWA

Perth

KalgoorlieKambalda

A

Stone et al, 2005

B

A

B

KSL

DCB

DFD

KAM

DCB

SO

DCB

DFD

A B

Repulse Fault

Nautilus Shear

DCB

DCB

PBS

Local domains of intense biotite± anhydrite

Anhydrite± biotite± epidote± quartz± carbonate

Best pyrite Au (>1ppm)+Pyrite

0 400 m

δ13C

-15

-10

-5

0

5

0 10 20 30 40

δ18O

CO2 - SO2 – CH4Anhydrous Domain

Hydrous Domain

CH4

SO2

δ13C

-15

-10

-5

0

5

0 10 20 30 40

δ18O

3CH4 + 4SO2 = 3CO2+ 2H2O + 4H2S

Negative deviation δ13C– SO2 oxidizing CH4

CH4

SO2

CH4 +H2O

δ13C

-15

-10

-5

0

5

0 10 20 30 40

δ18O

3CH4 + 4SO2 = 3CO2+ 2H2O + 4H2S

Negative deviation δ13C– SO2 oxidizing CH4

CH4

SO2

CH4 +H2O

δ13C

-15

-10

-5

0

5

0 10 20 30 40

δ18O

CO2 + 4H2 = CH4+ 2H2O

Positive deviation δ13C– H2 reducing CO2

CH4

SO2

CH4 +H2O

H2 +H2O

00000000000

-10 +8 ‰

SO2

δ34S pyrite Au deposits

H2

(H, Na, N, C, Cl, metals)

10km10km

100 km100 km

1000 km1000 km

HH2 2 fluxflux

sealseal

Melts & Melts &

COCO22--SOSO2 2 fluidsfluids

Metal Province

Aqueous domain

δ34S variationin volcanic hosted Ni?

Oxidizedpathways

Reducedpathways

Extreme reductionof magmatic sulphate in the sodic alteration zone

Ridgeway

Wilson et al., 2004

Oxidizedpathways

Reducedpathways

Cadia & environs: Redox mapping in porphyry environment

Aid to near mine exploration

Po

Py-Asp

Bn-Ccp-Py

pH 1.8 3.2 4.6 6.0 8.0 10.5log sumS -3.4 -3.3 -2.2 -1.5 -0.47 + 0.7

-31

-30

-29

-28

-27

-26

-25

-24

-23

-22

-2.5-2.3-2.1-1.9-1.7-1.5-1.3-1.1-0.9-0.7-0.5-0.3-0.1log KCl/NaCl

log

fO2

Chlorite

Tourmaline

Biotite

Amphibole+

Biotite

Epidote

py

po

hmmt

pymt

hm

mt

mt po

am

am am

CO2 aqCH4 aq

Oxi

dize

d400°C

G G’A

lbite

Quartz+

Albite

Anhydritesaturation

HSO4 –

H2S aq

H2S

aq

HS

-

CIM Toronto, April 2005

??

??

??

??

??

?? ??

??

??

Ni?Ni?

A

100 km

█ ~1590 Ma: Gawler Range Volcanics (bimodal, mainly felsic)

█ ~1590 Ma: Gawler Range Volcanics (bimodal, mainly felsic)

faults

█ ~1595-1575 Ma: Hiltaba Suite granitoid and mafic intrusions;

█ ~1595-1575 Ma: Hiltaba Suite granitoid and mafic intrusions;

IOCG crustal settingIOCG crustal setting

▌~1590-1575 Ma: Olympic Cu-Au province;

▌~1590-1575 Ma: Olympic Cu-Au province;

??

??Palaeoprot.orogenic belt

Seismic& MT lineSeismic& MT line

CIM Toronto, April 2005

SN

5

0twt, secs

10

15

50 km V:H=1

Coloured MT image courtesy R. Gill, G. Heinson, N. Direen at The University of Adelaide, and published in Thiel et al., (2004).MT image overlays GA-PIRSA seismic data with early interpretive linework by GA-PIRSA-UofA.

High conductivity (Prot?)High conductivity (Prot?)

Low conductivityLow conductivity

Low conductivity (e.g. Archaean gneiss)Low conductivity (e.g. Archaean gneiss)

Crustal architecture of the Olympic Dam region:magneto-telluric transect along seismic line

Crustal architecture of the Olympic Dam region:magneto-telluric transect along seismic line

OD

Track GRAPHITE through the crustTrack GRAPHITE through the crust

0

2.0

3.0

4.0

4.5

Earth H

istory

Au

AuAu

1.0

Potential to explain

•Time scales

• Length scales

• Province scale alteration

• Build genuinemineral system models

EarthEarth--system modelssystem models