Uncovering the basement geology of the Thomson Orogen and plans for regional stratigraphic drilling.

1. Southern Thomson Project update
Uncovering the basement geology of the Thomson Orogen and plans for regional
stratigraphic drilling
Dr Ian Roach
Southern Thomson Project Activity Leader

2. Southern Thomson Project update: Exploration In The House 2016
Introduction
The UNCOVER Initiative
Southern Thomson Project
Progress to date
Stratigraphic drilling program
Drilling in the southern Thomson!

3. Setting the scene:
Australia’s cover
opportunity
Most of Australia's proven
mineral reserves occur
where rocks stick out of the
ground. We need to find:
1. Extensions to known
mineral provinces
2. Entirely new provinces
3. Opportunities at depth
Southern Thomson Project update: Exploration In The House 2016
Richard Blewett
Southern
Thomson
Project

4. The UNCOVER Initiative
Australian Academy of Science 2012:
Searching the Deep Earth: a vision for exploration
geoscience in Australia
Southern Thomson Project update: Exploration In The House 2016
Commonwealth-States-Territory:
Standing Council Energy & Resources
(SCER - COAG)
National Mineral Exploration Strategy
(2012) Richard Blewett

5. The Southern Thomson Project
National Collaborative Framework (NCF) project:
– Geoscience Australia
– Geological Survey of New South Wales
– Geological Survey of Queensland
Aim: Better understand geological character & mineral
potential through new multi-disciplinary geophysical,
geochemical and geological data
Objective: To provide the mineral exploration industry with
pre-competitive data and knowledge that reduces risk and
encourages investment
Impact: Increased mineral investment in the region
Southern Thomson Project update: Exploration In The House 2016

6. Progress: Multi-element surface geochemistry
Preliminary results:
• Mobile Metal Ion® (MMI) selective leach
– Principal Components Analysis shows broad agreement with tectonic elements,
distal footprints of mineralised basement terrains
• Hyperspectral scanning of
surface samples
– Validate remote sensing data
• GA Record in preparation
Southern Thomson Project update: Exploration In The House 2016
Image: overbank sediments MMI Principal Component 1
Ca,Sr,Cu,Mg,
Au,Mo,Ag
Sm,Nd,Pr,Th,
La,Ce
Tibooburra
Hungerford
Bourke
Brewarinna
Wilcannia
Eulo

7. Airborne electromagnetic survey
• Cover thickness mapping over the Eulo
Ridge
• Identify unmapped basement highs
• Risk reduction for further geophysics and
drilling
• Adjunct to magnetotelluric data acquisition
and gravity modelling of the Thomson-
Lachlan orogen boundary
GA Record 2015/29 and data are freely available through the
Geoscience Australia website:
www.ga.gov.au
Search for “Southern Thomson”
Southern Thomson Project update: Exploration In The House 2016
QLD
NSW
AEM depth to
basement model

8. New data acquisition:
AEM survey extension
Southern Thomson Project update: Exploration In The House 2016
New pre-competitive AEM survey:
• New regional survey in Louth &
Enngonia areas
• Infill previous sites where
basement highs were located but
poorly imaged
• Overfly proposed
drill sites for data
validation
Flying May-June 2016
QLD
NSW

9. Geological synthesis – seamless basement geology
• Solid geology and structural synthesis
• Improve understanding of basement geology and structural evolution
• Merge geophysical &
geological interpretation
across the border
• Develop unit descriptions
• Provide structural framework
• Inform future drilling targets
(sample knowledge gaps)
• Publish as a GIS
package (Purdy, Hegarty &
Doublier)
Southern Thomson Project update: Exploration In The House 2016

10. Isotopic dating
New data on magmatic, metamorphic and
mineralisation ages:
• Builds on recent collaborative
geochronology with GSNSW & GSQ
• New Ar-Ar, K-Ar ages plus XRD
on cleavage minerals for age
of deformation
• ~80 new U-Pb SHRIMP ages from
industry drill core, more than half already published
• New publications released or in preparation:
• Cuttaburra-F1
• Detrital zircon stratigraphic constraints
• Hf-O isotopes on magmatic rocks
Southern Thomson Project update: Exploration In The House 2016
New isotopic age samples
QLD
NSW

11. Mineral systems synthesis
• Review current isotopic literature
• Collect new S and Pb
from available cores
• New results from
Cuttaburra-F1 prospects
better define mineralisation
age (GA Record in prep)
• Reassess mineral
potential of southern
Thomson Orogen based
on review, solid geology
and new industry results
• Waiting on new drilling
Southern Thomson Project update: Exploration In The House 2016
Diorite
402 ± 3 Ma
Granite
421 ± 2 Ma
Orogenic gold
“Intrusion-related Au”
Sn-W skarn
(Rosemary Hegarty, GSNSW)
Cuttaburra/F1
Armistead and Skirrow in prep

12. Pre-drill geophysics
Project staff completed pre-drill geophysics acquisition in October 2015
Depth to basement soundings acquired by:
• Seismic refraction
• Passive seismic
• Audio MT
• (Resistivity)
Develop an “Explorer’s Toolbox” of
geophysics methods to aid industry
Publish results post-drilling
Southern Thomson Project update: Exploration In The House 2016

13. New drilling this winter!
Data and information
already gained is
guiding a new
stratigraphic drilling
program
Increase our knowledge
of the geology and
mineral potential of the
southern Thomson
Orogen, reduce
exploration risk
Aiming for final
project delivery
end 2017/18 FY
Southern Thomson Project update: Exploration In The House 2016
QLD
NSW

14. Stratigraphic drilling program
Objective: To provide the mineral exploration industry with pre-
competitive data and knowledge that reduces risk and
encourages investment in the region
Drill targets selected after a knowledge gap analysis:
• Solid geology, geochronology, mineral systems
Pre-drill geophysics used to inform:
• Depth to basement for primary/alternate drill sites
• Drilling budget estimates
Focus on regional stratigraphic packages from solid geology
Drilling RFT released Wednesday 20 April, closes 10 May
Southern Thomson Project update: Exploration In The House 2016

15. Phone: +61 2 6249 9111
Web: www.ga.gov.au
Email: clientservices@ga.gov.au
Address: Cnr Jerrabomberra Avenue and Hindmarsh Drive, Symonston ACT 2609
Postal Address: GPO Box 378, Canberra ACT 2601
Thank you
Near Eulo. What lies beneath?
www.ga.gov.au
Search for “Southern Thomson”