Granites and mineral deposits in NSW - SMEDG BLEVIN.pdf · Granites and mineral deposits in NSW...
Transcript of 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””
PHIL BLEVIN, SMEDG – APRIL 2009
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.
PHIL BLEVIN, SMEDG – APRIL 2009
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.
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
PHIL BLEVIN, SMEDG – APRIL 2009
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”
PHIL BLEVIN, SMEDG – APRIL 2009
• 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
PHIL BLEVIN, SMEDG – APRIL 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.
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
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?
PHIL BLEVIN, SMEDG – APRIL 2009
“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.
PHIL BLEVIN, SMEDG – APRIL 2009
Zircon REEZircon REE
Goonumbla regionalsamples
Goonumbla regionalsamples
Ce4+ & Eu3+ Vs Ce3+ & Eu2+
PHIL BLEVIN, SMEDG – APRIL 2009
• The remarkable Gilgai-Tingha Snsystem in New England.
• Strongly magnetic “tin granite”.• Magnetics, petrology,
geophysics.
PHIL BLEVIN, SMEDG – APRIL 2009
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!
PHIL BLEVIN, SMEDG – APRIL 2009
Courtesy of Tony Kemp, JCUNQ
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
CassiteriteCassiterite compositions comparedcompositions compared
I-type - Emmaville S-type - Kikoira
NbNb & Ta& Ta
HREEHREE
WW
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
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.
PHIL BLEVIN, SMEDG – APRIL 2009
Cu MoAuSn W
Mo Au
Sn W
Sn W
Sn W Au
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
252 Ma
286 Ma
247 Ma
TinMolybdenumGold
Average K/Rb ratio of plutons
PHIL BLEVIN, SMEDG – APRIL 2009
““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
PHIL BLEVIN, SMEDG – APRIL 2009
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)
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
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.
PHIL BLEVIN, SMEDG – APRIL 2009
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
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
PHIL BLEVIN, SMEDG – APRIL 2009
Geochem
Geochem&
Dates
PHIL BLEVIN, SMEDG – APRIL 2009
HHP potential, Sydney basinHHP potential, Sydney basin
Courtesy of Bruce Chappell and Doone Wyborn
Mt Bright
Touga/Tullyangela
Woronora
PHIL BLEVIN, SMEDG – APRIL 2009
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.