Download - 2015 Broken Hill Resources Investment Symposium - Geology Survey of South Australia - Stephan Thiel
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Deep crustal architecture as a context for mineral discovery in the Curnamona. Stephan Thiel
Geological Survey of South Australia
Broken Hill Symposium, 27th May 2015
www.statedevelopment.sa.gov.au
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UNCOVER – template for mineral exploration
2 Department of State Development
1. Characterising the cover
2. Australia’s whole lithosphere architecture
3. 4D geodynamic and metallogenic evolution
4. Characterising and detecting distal footprints
Themes Scale
Continental scale
Regional scale
Camp scale
Deposit scale
MT images from a few tens of meters to hundreds of kilometers
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Exploration across scales
3 Department of State Development Groves & Santosh, 2015, GF Griffin et al., 2013, Nature Geoscience
Plume interaction with cratonic setting Generalised convergent margin settings
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Fast vs slow mantle lithosphere
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Geodynamic model of the Tasmanides
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Moresi et al., 2014 Nature
Rawlinson et al., 2014 Geology
Seismic anisotropy due to slab roll back
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Broken Hill
Kate Robertson, U of A
Geophysical observables from the Gawler into Curnamona
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Seismic reflection
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Flinders AusLAMP MT
8 Department of State Development Kate Robertson, U of Adelaide
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Regional MT geotransects
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Peter Milligan, GA
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Role of deep fluids in mineral genesis – reducing agent?
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Example of high-resolution (1 km) MT survey across Beverley U-mine
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Is electrical resistivity a proxy for strain and metamorphism?
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Thiel et al., in prep
Extension
Compression 1
Present compression
Celerier et al., 2005, Tectonics
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Terrane scale exploration - AusLAMP SA 50km grid
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AusLAMP extension – University of Adelaide
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3D inversion 88 sites included in modelling with emphasis on data quality: • Red – new AusLAMP
sites • Blue – legacy long-
period MT sites • Open – yet to be
collected and included in modelling
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3D resistivity models
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Mantle fertilisation beneath the Gawler
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Rawlinson et al, 2014, Lithos
Terrane-scale
AusLAMP SA MT
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Mantle-crust connection beneath Stuart Shelf
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rox0
00
RO
X001
RO
X003
RO
X005
RO
X006
rox0
07
RO
X009
RO
X011
RO
X012
RO
X013
RO
X014
rox0
15ro
x016
RO
X017
RO
X018
RO
X019
RO
X020
RO
X021
RO
X022
RO
X023
RO
X024
RO
X025
RO
X026
RO
X027
rox0
29
RO
X031
RO
X033
RO
X035
RO
X037
rox0
38
OD
01O
D02
OD
03O
D04
OD
05O
D06
OD
07O
D08
OD
09O
D10
OD
12O
D14
OD
15O
D16
OD
17O
D18
OD
19O
D20
OD
22O
D23
OD
24O
D25
OD
26O
D27
OD
28O
D29
OD
30O
D31
OD
32O
D34
OD
35O
D38
OD
40O
D41
OD
42O
D43
OD
44O
D45
OD
46O
D47
OD
48O
D49
OD
50O
D52
OD
53O
D54
OD
55O
D56
OD
57O
D58
OD
59O
D60
OD
61O
D62
OD
63O
D64
OD
65O
D66
OD
67O
D68
OD
69O
D70
OD
71O
D72
OD
74O
D75
OD
76O
D78
OD
79O
D80
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
0-10000-20000-30000-40000-50000-60000-70000-80000-90000
-100000-110000-120000-130000-140000-150000-160000-170000-180000
0-10000-20000-30000-40000-50000-60000-70000-80000-90000
-100000-110000-120000-130000-140000-150000-160000-170000-180000
Distance (Km)
Dept
h (m
)
1000
794
631
501
398
316
251
200
158
126
100
79
63
50
40
32
25
20
16
13
10
8
6
5
4
3
3
2
2
1
1
Ohm.m
Updated from Heinson et al., 2006
Regional-scale
Archaean core
Archaean core
Olympic Dam
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Conclusions
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• AusLAMP SA will highlight the terrane to regional lithospheric architecture of the state
• Show fluid related metasomatism events (mantle) and fluid pathways (crust) conducive to “fertility corridors”
• MT needs better integration and analysis with reflection and passive seismic arrays with petrophysical constraints
• Fluid pathways appear structurally controlled and governed by geodynamic controls (stress, rheology)
• Future targeted camp-scale MT and other geophysical surveys will greatly benefit from the lithospheric architecture provided through AusLAMP SA
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Stephan Thiel
www.statedevelopment.sa.gov.au
Department of State Development Level 4, 101 Grenfell Street Adelaide, South Australia 5000 GPO Box 320 Adelaide, South Australia 5001
T: +61 8 8204 1181 E: [email protected]
Acknowledgement • Philippa Mawby, Bruce Goleby and Geoff Axford (AusLAMP core field crew, University
of Adelaide), numerous students for field work • Katherine Betschart, Ian Hopton and David Love (DSD) for liaison and access • AARD for Aboriginal liaison • WPA, National Parks SA, traditional owners and numerous pastoralists for land
access • AuScope MT equipment pool