Granites and mineral deposits in NSW - SMEDG BLEVIN.pdf · Granites and mineral deposits in NSW...

Granites Granites and and

mineral deposits mineral deposits in NSWin NSW

PHIL BLEVIN, SMEDG – APRIL 2009

Phil Phil BlevinBlevinGeological Survey of NSWGeological Survey of NSW

Interconnected miarolitic texture

• Refer loosely to a wide range of felsic plutonic rocks. They comprise a major proportion of the continental crust.

• Granites redistribute significant amounts of material vertically within the crust.

• Most occur in areas where the continental crust has been thickened by orogeny, including continental arc subduction or collision of sialic masses.

• The majority of granites are derived by crustal anatexis, but the mantle is also likely involved. The mantle contribution may comprise heat and/or material.

Here we take the broadest view and include Here we take the broadest view and include intermediate and intermediate and felsicfelsic intrusivesintrusives..

Granites and Granites and ““granitesgranites””


Granites

Volcanics

NSW has a diverse range of granite related mineral deposits - Sn, W, Mo, Au, Cu, Ag, Pb, Zn, F…..

Diverse range of compositions and types, from primitive arc to S-types.

Substantial volume of failed granites.

Granites represent a data rich environment for research and exploration.


Granites Granites andand

““granitesgranites””

• Mapping of mineral systems. • Dating of mineral systems.• Fingerprinting mineral system geochemistry.• Better understanding of the fundamental controls on

magmatic fertility.

• Use these to better understand the distribution of mineralisation in time and space throughout the state.

• Develop new concepts.• Opportunities for existing and new commodities.


Igneous related mineral systems in NSW Igneous related mineral systems in NSW -- new worknew work

SMEDG – APRIL 2009

+2km

+1 km

0km

-1km

-2km

-3km

800 C°

Subvolcanicintrus ions

ConvectingMagma

Groundwater

Vapor

550C°

500C°

-4km

-5km

Exsolved magmaticbrine and vapor

A magmatic view of ore systemsA magmatic view of ore systems

• Compositional type (I, S..)• Differentiation processes.• Degree of compositional

evolution.• Oxidation state.• Physical parameters (level of

emplacement, volatile content, T etc)

This scheme assigns metallogenicassociations to granites. Source: Harris et al., 2003, after Shinohara and Hedenquist, 1997

10 310 210 110 010 -110 -210 -3

10 -1

10 0

10 1

Rb/Sr

Cu-Au

W(scheelite)

Cu-Mo MoW-Mo-Sn

± Au, As, Bi

Sn±W

Increasingfractionation

Increasing oxidation

Fe2O3 /FeO

Timbarra/Kidston/Red Dome Lucky Draw

Mineral Hill

Browns Creek Mt Adrah

The The redoxredox--fractionation storyfractionation story



CORECORE

PROXIMALPROXIMAL

DISTALDISTAL

Cu MoBi W

Pb ZnAg

As (Au)

F BaSe Hg U DEPOSITDEPOSIT

TOTODISTRICTDISTRICT

SCALESCALE

PROVINCEPROVINCESCALESCALE

FRACTIONATION

Cu (Zn)

Pb ZnAg Au

(Cu Mo Te)

Au As Sb

Ca

Por. Cu

Cu ZnPb

Bi AgAu

(As SbAu)

Ca

Cu-Mo

Cu AuBi Te

Pb CuZn

As AgSb Au

F, U

FelsicAu por.

There is a complete metal gradation that compliments the continuous variation of igneous rocks in redox/frac space.

Gold in felsic magmatic systemsGold in felsic magmatic systems

EXTERNAL SOURCES• Wall rocks…• Mafic magmas…

INTERNAL SOURCES• Au-rich to begin with…• Efficient concentration…

Caveat emptor….

• The fractionated felsic shallow chambers are the tops to more extensive plumbing (not representative of whole the magmatic system).

• Magmatic compositions and intensives allow passage of Au through the magma to the hydrothermal stage.

• Magnetite?????

Au ?

CuMoSn

IRGD “window”


• Huge effort over last decade and half on fluid/vapour transport and partitioning of metals.

• Driven by early observations of Cu partitioning into the vapour phase of the famous Cu mineralised Mole Granite.

• Infamous statement that porphyry Sn systems will be found under porphyry Cu deposits.

• Auditat 2009 concluded that metallogenic fertility is a function of magma composition

The primacy of magma compositionsThe primacy of magma compositions

Haven’t we….?

…apologies to the movie “Top Secret”Seo et al, in press, 2009


……déjà vu?

0.1

1

10

100

0 2 4 6 8 10 12 14

susc

eptib

ility

10-3

SI

FeO*

Magnetic susceptibility is a function of Magnetic susceptibility is a function of oxidation state AND the total Fe content of the oxidation state AND the total Fe content of the

rock.rock.


0

20

40

60

80

100

120

140

0 10 20 30 40 50

Very Stron

glyOxid

ised

Moderately Oxidised

RColour Index3

Mag Sus10-3 SI units


A robust and practical scheme for classifying igneous rocks

OTLM StudiesOTLM Studies(Optical transmission light microscopy)

What is the relationship between the present oxidation state of igneous rocks versus the oxidation history of those magmas and their sources? Guess what mineral will help solve this?


“Early crystallization of magnetite can play a mitigating role in the ability of a calc-alkaline magmatic system to yield a Au-rich ore fluid.”

Zircon!

Zircon ForensicsZircon Forensics

To better understand the magmatic development of the Macquarie arc from the

perspective of the intrusive complexes

To better understand the magmatic development of the Macquarie arc from the

perspective of the intrusive complexes

• What are the magma sources, and how have these changed or interacted over time?

• Is there a link between magma generationprocess and metallogenic fertility?

• What are the tectonic implications?PHIL BLEVIN, SMEDG – APRIL 2009

Zircons are robust mineral Zircons are robust mineral archivesarchives

• U-Pb isotopes (SIMS)

• O isotopes (SIMS)

• Lu-Hf isotopes (LA-ICPMS)

• Trace elements (LA-ICPMS)

• Thermometry (Ti content)

• U-Pb isotopes (SIMS)

• O isotopes (SIMS)

• Lu-Hf isotopes (LA-ICPMS)

• Trace elements (LA-ICPMS)

• Thermometry (Ti content)

Will be used to understand age, origin and oxidation controls on magmas.

Will be used to understand age, origin and oxidation controls on magmas.


Zircon REEZircon REE

Goonumbla regionalsamples

Goonumbla regionalsamples

Ce4+ & Eu3+ Vs Ce3+ & Eu2+


• The remarkable Gilgai-Tingha Snsystem in New England.

• Strongly magnetic “tin granite”.• Magnetics, petrology,

geophysics.


Applications to other systems across the stateApplications to other systems across the state

Conrad

MoleInverell

Continental crustlow εHf, high δ18O Continental crustlow εHf, high δ18O

Mantle wedgehigh εHf, low δ18OMantle wedgehigh εHf, low δ18O Basaltic slab

(upper) high εHf, 18O-enriched(lower) high εHf, 18O-depleted

Basaltic slab(upper) high εHf, 18O-enriched(lower) high εHf, 18O-depleted

Sediment (18O-enriched)terrigenous: low εHfpelagic: high εHf

Sediment (18O-enriched)terrigenous: low εHfpelagic: high εHf

Combined isotope systems within zirconsCombined isotope systems within zircons

NdNd & & HfHfuncoupling uncoupling useful too!useful too!


Courtesy of Tony Kemp, JCUNQ


CassiteriteCassiterite: the new : the new ““zirconzircon””• A new project with PRISE/RSES (Marc Norman).• Develop SHRIMP based U-Pb dating for cassiterite.• Trace element geochemistry by LAICPMS for Nb-Ta, Ti, Zr-Hf, Sc, W, Fe,

In, U, Th…..• Potential for Hf isotopes – actually trace the source of the ore fluids

themselves.

• Will allow rapid dating and characterisation of cassiterite for regional assessment and metallogenic reconnaissance.

• Initial pilot project funded by ANU.• Samples from NSW will be used.• Possible ARC project depending on

outcomes.

Initial results extremely encouraging:• High U, low Pb• Dates for Kikoira, Elsmore, Emmaville


CassiteriteCassiterite compositions comparedcompositions compared

I-type - Emmaville S-type - Kikoira

NbNb & Ta& Ta

HREEHREE

WW


10 2

10 3

10 4

10 5

10 6

10 7NORTH PARKES

1601501401301201101009080706010 1

10 2

10 3

10 4

10 5

10 6

Mo 97W 182Re 185Cu 65Se 82Pd 105

Time

KOUNRAD

LAICPMS analysis of molybdenitesLAICPMS analysis of molybdenites

15014013012011010010 -3

10 -2

10 -1

10 0

10 1

10 2

10 3

10 4

Kounrad

BinghamN. Parkes

BrendaKingsgate

Time

Re185/W182

MOL 5 Deepwater, NSW


Molybdenum and Molybdenum and cassiteritecassiterite dating.dating.

Collaborators:Marc Norman: RSESRob Creaser: U. Alberta

Re-Os

Cst U-Pb

Re-Os*

PLANNED

*: Includes “pre Survey”Re-Os dating

KingsgateMo Bi

King ConradSn Ag In (Re-Os)

CargoCu Au

WhipstickMo Bi Au

YiddahCu Au

WymahW Mo

ArdlethanSn

Fountaindale

Holbrook

Perrins

Glen Eden

ElsmoreSn

Rye ParkSn W (Re-Os)

Cobar (asp) ?

Doradilla ?Gundle

Sn

EmmavileSn

Ruby CreekMo

MoleSn

K/Rb!( 21 - 140

140 - 250

250 - 300

300 - 400

>400

Variability in granite compositionsVariability in granite compositions

Compilation of granite data is being used to:

• Map large scale variability in the Tasmanides

• Understand source controls

• Follows the observed metallogeny

• Will provide info on heat generation and potential

• K and Rb substitute into same minerals.• Rb slightly excluded relative to K.• Rb thus increases with crustal reworking

relative to K.• K/Rb DECREASES with crustal evolution.


Cu MoAuSn W

Mo Au

Sn W

Sn W

Sn W Au


K/K/RbRb ratio follows ratio follows geophysical and geophysical and ““basementbasement””terrane boundariesterrane boundaries

0.9

1

1.1

1.2

1.3

1.4

5.5 105 6 105 6.5 105 7 105 7.5 105 8 105

ASI MulgowrieASI BindaASI BullenbalongASI WyangalaASI WollogorongASI Davies

ASI

AMG_Zone_East

(Jenked)

Sn W Mo

Av_KRb72 - 131131 - 184184 - 225225 - 308308 - 600


252 Ma

286 Ma

247 Ma

TinMolybdenumGold

Average K/Rb ratio of plutons


““New metalsNew metals””: Indium: Indium

• Indium occurs in several types ore systems. In vein and porphyry style Snsystems, indium mainly reports in the sulfide stage (Sn -> Cu-Bi-Pb-Ag-As).

• Principal ore forming minerals (sph, ccp, cst, stn) contain 75% of the bulk In.

• Other minerals include roquesite, kesterite….

• 28% of known world reserved in one deposit (Mount Pleasant).

• Metallurgy (and thus reserves) in other deposit types are difficult to establish.

In NSW:• In reported from Conrad Howells• Apocryphal(?) stories from the 1970s that Sn

smelters recovered In from New England cst.• Comparative studies suggest New England I-

types high potential for In.

Indium: geology, mineralogy, and economics. Schwarz-Schampera & Herzig, Springer, 2002; and New Brunswick Dept Natural Resources website: www.gnb.ca

Analogy for New England Analogy for New England –– the Canadian Maritimesthe Canadian Maritimes


http://www.gnb.ca/

Ground up GraniteGround up Granite• Granite being mined directly for manufactured sand

– The biggest quarrying operations in Asia (Karimun 6-8 Mtpa).– Angularity and fines have been an issue – being addressed by

blending, new crushing (eg. cone) and screening technologies and processes.

– Manufactured granite used for three gorges dam.

• New Boral Quarry– Marulan Granodiorite, production up 3.5 Mtpa– High quality aggregates for use in the Sydney

metropolitan concrete and asphalt markets. – Replace exhausted river sand deposits– Close to Sydney, adjacent a railway– Construction late 2009 (~200 jobs), with operations commencing

approximately two years from that time (~30 jobs). (From Boral website)


Unit K2O%

SiO2

%P205

%Zr Ce Y

67 19

17

19

31

26

73

73

69

Th

72

71

52

68

68

195

69

34

28

29

18

18

110

135

181

131

Walcha Road 4.0 0.24

Gulgong high 0.08

Tarana 4.6 0.07

Young 3.5 0.14

Marulan 3.8 0.05


Potential for recovery of accessories? Potential for recovery of accessories?

• Granites have accessory zircon, apatite, ilmenite and rutile.

• Potential for recovery of these if “quarrying” is paying for the mining bill?

• Potential benefit of local buyer (zirconiaplant, Murray basin sand miners?).

Sand flightSand flight……..Granite Miners Seek Help from Trade Ministry: The Jakarta Post, 23 March 2007, page 14

Approximately 20 barges carrying up to 3,000 tons of granite from the Riau islands to Singapore have been detained following the banning of sand exports. The Navy detained the barges due to suspicions of sand smuggling and violations of maritime regulations.



HPE are concentrated in granites but with variable abundances. Typically the most felsic (light-coloured) granites have heat productions (A) of about 3 µW/m3 – less felsic granites have lower values.

Some granites have higher heat production, those greater than 5 µW/m3 the High Heat Producing (HHP) granites. 12.7% of the more than 8000 granites that B. W. Chappell analysed from eastern Australia are HHP.

The heat production (A) of a rock is given by:

A = 0.01 * ρ * (3.48 * K% + 2.56 * Thppm + 9.52 * Uppm)

where ρ is density in tonnes/m3 (or SG) and A is µW/m3

Granite Heat PotentialGranite Heat Potential

Courtesy of Bruce Chappell and Doone Wyborn


Some examples of heat production

K% Thppm Uppm Aaverage crust 1.25 4.5 1.2 0.8SE Aust seds 2.9 17.4 3.3 2.5SE Aust granite 3.1 19 4.8 2.9Cornish granite 4.3 15.4 12.8 4.8Innamincka 3.7 33 18 7.3Stinking Cornishman 3.7 65 43 15.9

HGU0.2 - 1.71.7 - 2.62.6 - 3.83.8 - 5.65.6 - 8.4

0

1

2

3

4

5

6

.01 .1 1 5 10 2030 50 7080 90 95 99 99.999.99

AMIRA database Heat flow

A_WologorongA_BathurstA_BindookA_OberonA_Marulan

Hea

t Flo

w (H

GU

- m

wm

-3)

Cumulative Percent

Carboniferous Granite StudyCarboniferous Granite StudyDated: Chapmans Ck, Oberon, Tarana,

Lett, Duronal, Wuuluuman & Gulgong

341 – 328 Ma

Heejin Jeon and Ian WilliamsRSES, ANU

• SHRIMP dating• Hf and O isotopes• Chemistry

• Dating of granites in south, Sydney Basin windows, mineralised & HHP granites.

• Metallogenic and tectonic implications.• Geothermal implications.

Mo

Au-Bi

Sn


Geochem

Geochem&

Dates


HHP potential, Sydney basinHHP potential, Sydney basin

Courtesy of Bruce Chappell and Doone Wyborn

Mt Bright

Touga/Tullyangela

Woronora


Granites are more than just fancy kitchen surfacesGranites are more than just fancy kitchen surfaces…………. .

The Geological Survey of NSW (The Geological Survey of NSW (MinSysMinSys) are undertaking new ) are undertaking new studies on all aspects of granite and related rocks from an applstudies on all aspects of granite and related rocks from an applied ied metallogenic aspect to better understand the known metallogenic aspect to better understand the known metallogenymetallogeny and and what controls it and to map potential for a range of new commodiwhat controls it and to map potential for a range of new commodities. ties.

We also invite industry participation in these projects.We also invite industry participation in these projects.

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