southern thomson project update

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

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!

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


Richard Blewett

Southern Thomson

Project

The UNCOVER Initiative Australian Academy of Science 2012:

Searching the Deep Earth: a vision for exploration geoscience in Australia


Commonwealth-States-Territory: Standing Council Energy & Resources (SCER - COAG) National Mineral Exploration Strategy (2012)

Richard Blewett

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


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


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

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”


QLD NSW

AEM depth to basement model

New data acquisition: AEM survey extension


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

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)


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


New isotopic age samples

QLD NSW

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


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

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


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


QLD NSW

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


Phone: +61 2 6249 9111 Web: www.ga.gov.au Email: [email protected] 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”

southern thomson project update

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