After emerging from the resources wilderness thanks to its world-class geology and industry-friendly government policies, South Australia is now a leader in Australian mining and hydrocarbon developments over the last decade. In little more than a decade the State has gone from four operating mines to more than 20 and is rated Australia’s second most popular exploration destination. With a comprehensive review of the Mining Act under way, the State’s attractiveness as a place for resources and energy investment is expected to be strengthened. South Australia is now a leader in the exploration for next generation energy sources with companies such as Santos and BP leading the charge, while initiatives such as the Government’s Copper Strategy – designed to treble annual copper production to 1 mtpa – is set to establish the State as one of the world’s premier producers of the red metal. In the energy space, uranium and nuclear energy is another area of keen interest, with the South Australian Government initiating a Royal Commission into Participation in the Nuclear Fuel Cycle in 2016. The State has become synonymous with innovation, cutting-edge development and a remarkable rate of discovery. From uranium prospects, to geothermal energy and the buoyant hydrocarbons sector, South Australia is now a leader in the exploration for next generation energy sources. With full support from the Department of State Development, the South Australian Resources and Energy Investment Conference will continue to showcase this burgeoning sector in 2017. From copper plays in the Gawler Craton, to iron ore and graphite developments on the Eyre Peninsula and the emergence of the State as a new hydrocarbon frontier, South Australia’s resources potential is at last being fully recognised. The conference will feature the success stories and emerging players in the State from both minerals and oil and gas and will also tackle thorny industry issues such as infrastructure, corporate social responsibility and the future of the Woomera Prohibited Area.

1. Reawakening theReawakening the
CurnamonaCurnamona
Province – a 3DProvince – a 3D
perspectiveperspective
Andrew Burtt – PIRSA
Helen Williams – Monash University
Philippe Calcagno – BRGM, France
EXIT

2. • To fully understand the physical characteristics
of geological features of the earth we need to be
able to see them in 3D
• 3D models allow us to incorporate all available
data and foster multidisciplinary interaction
• Modern, efficient exploration will increasingly
utilise 3D modelling and visualisation software
Introduction

3. CURNAMONA PROVINCE
• Why a 3D model of the Curnamona Province?
– Complex geology, multiply deformed
– World class Pb-Zn-Ag deposit
– Several Cu-Au prospects
– Limited outcrop
– Require a new perspective for mineral exploration

4. CURNAMONA PROVINCE - GEOLOGY
• Palaeo- to Mesoproterozoic
– Metasediments
– Metavolcanics
– Igneous intrusives
• Outcrop limited to Broken Hill
and Olary Domains, Mt.
Painter/Babbage
• Neoproterozoic, Cambrian,
Mesozoic and Cainozoic
cover
• Pb-Zn-Ag
• Cu-Au
Curnamona
Province

5. • Differences between Broken Hill Domain (East) and Olary
Domain (West):
– Broken Hill Group
– Mineralisation
– Granites (Barovich and Foden, 2002)
– Mafic intrusives (Rutherford, 2005)
• Important to look at the regional perspective

6. 3D MODEL - BASIC DATA (BUILDING BLOCKS)
• Solid geology interpretation
• Geology maps
• Potential field data
• Depth to basement map
• Structural data
• Seismic data
• Drillhole data

7. A: 3DGeomodeller
Andrew Burtt - PIRSA

8. 3DGeomodeller – stratigraphy
Mundi Mundi Fault
Upper Willyama Upper Willyama
Lower Willyama Lower Willyama
Broken Hill Group
erosional surface?
erosional
surface?

9. 3DGeoModeller – map view
Depth to basement
3DGeomodeller plan view

10. 3DGeoModeller

11. 3DGeoModeller

12. Benagerie Volcanics
3DGeoModeller

13. Mundi Mundi Fault
3DGeoModeller

14. 3DGeoModeller – results
• To have Broken Hill Group only on eastern side, need
unconformity
• Granites restricted to top ~10 km of the crust
• Can easily see 3D geometries of upper crustal bodies but mid –
to lower crust remains unresolved
• Future plans
– 3D gravity inversion
– Subsequent editing
– Extra data – e.g. new Curnamona seismic survey

15. B: MapInfo Discover3D
Helen Williams – Monash University
• GIS context
• Combination of:
– upper crust: geological cross sections
– lower crust: potential field forward and inverse models
• Largest scale features = long-wavelength density variations
• Visualisation and comparison of different levels of the crust

16. Geological cross sections
• Show shallow features
• Based on:
– geology map
– interpretation of
potential field data
(short wavelength
features)
– structural data
Section 6600000N

17. Forward models
• Constraints:
– Vertical density profile is based on broad-
scale layering in the Broken Hill Seismic
Reflection Profile (Drummond et al., 1998)
• Most distinct reflector at 18 km depth
– Assumption that density increases with depth
– Simplified rock properties from literature

18. Forward model example
0 km 200 km100 km
40 km
0 km

19. MapInfo Discover3D – model

20. MapInfo Discover3D – model
N
N

21. MapInfo Discover3D – model
N
N
From above: From beneath:

22. N
Mt. Painter region (under cover)
High density
Crocker Well
Low density
Portia
Low density
Gravity Inversion

23. MapInfo Discover3D - results
• Upper crustal features
– Sedimentary basins, granites
– Correlation between density variations and prospects
• Mid – to lower crustal features
– Dense body ~18 km beneath eastern Curnamona (Broken
Hill); continuous, arcuate, dipping margins, ~10 km thick
• Visualisation of characteristics (geometry, depth extent, width,
length) in 3D

24. Implications of dense body at depth
• Density contrast at depth is analogous to observations in Mt. Isa
– Deep crustal contrast between Eastern and Western Fold Belts
• Pre-Willyama Supergroup/basin history
– Configuration of basement
– Ancient terrane suture; suspect terrane?
– Ancient failed rift?
• Basement beneath Broken Hill Domain different to Olary Domain
– How does this relate (if at all) to differences observed at the
surface?
• geochemistry, metallogeny, stratigraphy and metamorphic evolution

25. Conclusions
• Curnamona Province
– Complex terrane
– Under cover, therefore high potential for discovery
– Mineralisation (Pb-Zn-Ag; Cu-Ag)
– Many available geological and geophysical datasets
• 3D Model is an ongoing project; as new data is
collected, it can be added to framework

26. New high resolution gravity survey of Benagerie Ridge
• To increase understanding of upper crustal features
and processes:
– Magmatism
– Mineralisation
• Focus on Cu-Au mineral potential
• Added to 3D model can be directly and efficiently
compared with:
– regional gravity field
– features at depth
– features observed at the surface

27. New high resolution gravity survey of Benagerie Ridge
N
N

28. References
• Barovich, K.M. and Foden J.D., 2002. Nd isotope constraints on the origin of
1580 Ma Curnamona Province granitoids magmatism. In: Preiss, W.V.
(Ed.), Geoscience 2002: Expanding Horizons. 16th
Australian Geological
Convention, Adelaide, 2002. Geological Society of Australia. Abstracts,
67: 156.
• Rutherford, L., 2005. Metamorphism, Magmatism and Mineralisation. PhD,
Adelaide University
• Drummond, B.J., Fomin, T. and Leven, H.,1998. Constraints on structure and
composition of the Broken Hill Region from seismic reflection and
refraction studies. In: Gibson, G.M. (Ed.), Broken Hill Exploration Initiative:
abstracts of papers presented at the fourth annual meeting in Broken Hill.
AGSO Record 1998/25: 21-26.