Our best foot forward in new/old terrane: Delamerian Orogen progress

Tom Wise

Project Aims

To stimulate mineral exploration beneath cover of the Murray Basin by providing industry with new data and new constraints on the geological framework and mineral prospectivity in this greenfields region.

Delamerian region had not been an area of focus for the GSSA for a couple (or more) decades. Association with the MinEx CRC National Drilling Initiative gave a platform.

Best foot forward

Data release Delamerian project

• Update of baseline geoscience datasets

• Stocktake atlas of geoscience data published – useful as a reference point pre- and post-National Drilling Initiative

• New data and ground acreage released 1st Sept

Legacy data entry

90 cored holes re-loggedGraphic lithological logs accompanied by descriptions of the main lithologies, their contact relationships, deformational fabrics, and alteration facies.

42 drill holes from the Sherlock Cu-Pb-Zn prospect and 6 drill holes from the Anabama Cu-Mo prospect have been scanned

Delamerian cover thickness and magnetic source depth modelling datasets

AusLAMP resistivity imaging the entire Curnamona Province and most of the onshore extent of the Delamerian Orogen

Primary questions to be addressed:How did the eastern Gondwanamargin evolve from the Proterozoic into the Phanerozoic?

• Was there subduction at any stage along the SA segment of the Gondwana margin?

• Is the SA segment fertile for subduction/post-subduction related porphyry Cu-Au/Mo deposits?

• What is the nature and age of the continental rift/rifted margin sediments beneath the Murray Basin?

• Do Cambrian sequences of the NSW Koonenberry Belt (prospective for VMS) continue into SA?

• What is the age and nature of magmatic/hydrothermal systems?

• What is the nature and thickness of cover and are cover sequences able to illuminate basement mineralisation?

Two regions identified to focus future work including drilling.

Northern Area:• Targeting continuation of Loch Lily Kars belt.

Possible unconformity suggests some units may be post-Delamerian. Test back-arc models. Porphyry-fertile ~400 Ma intrusions?

Southern Area• Targeting continuation of N-S trending volcano-

sedimentary belts including possible Cambrian arc segment and younger (Ordovician-Devonian?) mafic-intermediate intrusions

Drill planning

• Coiled Tubing rig• Fixed number of holes in

southern area first, more flexibility in the north

• Stick to basement <350m

• Chips through to fresh basement, then cored interval

surface

Basement unconformity

Weathered basement

Fresh basement = CORE (1.5+ m)

?

• Trade off between detail on individual target features and covering a wider region

• Transects with multiple holes in target features along and across strike

Drill planning

Quondong Vale – Northern area• ~20 drillholes planned, varying

priorities• Intersect as many different

lithologies as possible• Characterise continuation of Loch

Lily Kars Belt• Investigate possible unconformity

between basement units• Map cover architecture across

reactivated structures• Link to regional structure – MT and

gravity profile• Assess VMS & Porphyry potential

Alawoona – Southern area• Fixed drillhole locations, set

number• Map across multiple N-S belts• Assess porphyry potential• Investigate possible volcanic

arc segment, and belt along strike from Sherlock

• Intersect as many different lithologies as possible –volcanics/intrusives of different ages/host rock

• Map cover architecture across structures

• Link to regional structure

Thursday’s Gossan

Porphyry style system superimposed on serpentinised peridotite

Dismembered arc segments in the Stavely Zone, Western Vic.

Analagous to possible arc segments in the Alawoona area?

Revuelta, 2017

Skiagia ornataOakvale 1 drillholeEarly Cambrian age

Province-wide detrital zircon geochronology

40Ar/39Ar geochronology

MT section

Magmatism: Geochronology and Geochemistry

Loxton 2 greywacke3 episodes of

metasomatic regrowth at Anabama

courtesy L. Stoian

courtesy K. Robertson

courtesy Naina

courtesy S. Curtis

Anabama

Potential Collaboration/EFTF opportunities

Contact

Tom Wise, Senior Geologist

Department for Energy and Mining11 Waymouth StreetAdelaide, South Australia 5000GPO Box 320Adelaide, South Australia 5001T: +61 8 8429 2576E: Tom.Wise@sa.gov.au

Mineral Exploration Cooperative Research Centre

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Acknowledgement of CountryThe Department for Energy and Mining (DEM) acknowledges Aboriginal people as the First Nations Peoples of South Australia. We recognise and respect the cultural connections as the Traditional Owners and occupants of the land and waters of South Australia, and that they continue to make a unique and irreplaceable contribution to the State.

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