Skip to content

ExploreSA: The Gawler ChallengeRex Minerals Hillside mine: program for environment protection and rehabilitation | Consultation on draft mining regulations | COVID-19 Updates for resources sector : fee relief | Accelerated Discovery Initiative Round 1 announced |

On this page

Murray Basin Section 15 expiry 31 August: Ground release with accompanying geoscientific data

On Tuesday, 1 September 2020, the Department for Energy and Mining will lift part of the Section 15, opening up parts of the Delamerian Orogen and Murray Basin to exploration licence applications.

The Geological Survey of South Australia will also publish a Phase 1 data release of new geoscientific information on the region.

MinEX CRC logo

The Geological Survey of South Australia has partnered with the MinEx CRC to undertake a National Drilling Initiative project on the under explored Delamerian Orogen. Collaborating with MinEx CRC researchers, this project will include a geoscientific drilling program and allied research to understand the geology and mineral potential of both the Delamerian basement and overlying Murray Basin cover.

Project rationale

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 project area map The Cambrian-Ordovician Delamerian Orogen is an arcuate orogenic belt with a strike length of approximately 15,000 km, encompassing eastern South Australia, western New South Wales, western Victoria and central and western Tasmania. It preserves the remnant of an accretionary plate margin formed along the eastern margin of the proto-Australian continent when it was part of the supercontinent Gondwana. The basement to the Murray Basin in South Australia is arguably the most poorly understood element of the Delamerian Orogen, flanked to the west by deformed Neoproterozoic-Middle Cambrian sedimentary rocks of the Adelaide Fold Belt, and to the east by volcanic arcs of the Grampians Stavely Zone in Victoria, and the Koonenberry and Loch Lily-Kars belt in NSW.

While the cover succession of the Murray Basin continues to be the target of exploration for heavy mineral sands, exploration for base and precious metals within the Delamerian basement has until now been almost solely focused along the western margin of the Murray Basin. This project will provide new constraints on the geological setting, deformational history, thickness of cover and prospective mineral systems of the basement beneath the Murray Basin.

Back to top

Work Program

Phase 1 – data release

A region encompassing the western Murray Basin was gazetted under section 15 of the Mining Act 1971 on 22 July 2019. This enabled the Geological Survey of South Australia (GSSA) and collaborative research partners to undertake a geological review and data audit of the Delamerian basement in this region. Two areas of interest have been identified for precompetitive geoscience activities, including a planned NDI drilling program. The remaining ground not retained after Phase 1 is open for exploration licence applications.

Delamerian Basement to the Murray Basin – Atlas of geoscientific and exploration data

Delamerian atlas cover This Atlas provides a pictorial summary of some of the geological and exploration data available for the Murray Basin region, including land access, current and previous exploration, mineral deposits and occurrences, surface and basement geology, drill hole and rock sample geochemistry, HyLogger data, constraints on depth to crystalline basement, potential field geophysics and magnetotellurics.

Download the atlas of geoscientific and exploration data

Interpreted basement geology to the Murray Basin and surrounds

Iterpreted basement geology map This geological framework provides an initial interpretation of the distribution of major structures, magmatic phases and volcano-sedimentary packages of the Delamerian Orogen.

Download the interpreted basement geology map

Delamerian igneous basement to the Murray Basin in South Australia: a drill core review - volume 1

Drillhole log imageResults of a logging project of a selection of exploration and stratigraphic holes that intersect Delamerian igneous and volcano-sedimentary basement to the Murray Basin:

  • 90 cored holes were re-logged, totalling almost 5,000 m in length
  • supported by examination of 260 thin sections
  • graphic lithological logs accompanied by descriptions of the main lithologies, their contact relationships, deformational fabrics, and alteration facies.

Download the drillcore review report

Extensive mineral exploration data updates

A comprehensive review of legacy data across the region and surrounding areas has led to the upload of extensive new data resources. The new data available in SARIG includes surface geochemistry, drill hole locations, lithology logs and downhole geochemistry.

DRILLHOLES

515,757m

56%

LITHOLOGY LOGS

428,202m

110%

DOWNHOLE GEOCHEM

152,822 samples

188%

SURFACE GEOCHEM

59,696 samples

284%

View these data layers in SARIG

Hyperspectral dataset update - 48 new HyLogged drillholes

HyLogger summary image 42 drill holes from the Sherlock Cu-Pb-Zn prospect and 6 drill holes from the Anabama Cu-Mo prospect have been scanned using HyLogger 3-3, in order to characterise primary and alteration mineralogy. This totals over 4300 m of new spectral data, complementing previously available HyLogger data in the Delamerian region.

Preliminary results have focused on the change in SWIR white mica and chlorite species and TIR feldspars in drill samples from the Anabamma Granite. While there are a greater variety of lithological and mineral interactions at the Sherlock Prospect, these results are yet to be analysed. All the spectral data is currently available for download via SARIG.

View the HyLogger data layer in SARIG

Delamerian cover thickness and magnetic source depth modelling

Depth modelling image

This package is a collection of datasets that portray actual or inferred depth to crystalline basement based on the Stratigraphic logs for over 2,000 drillholes.

In addition, the depths to the top of magnetic sources have been determined over eleven airborne total magnetic intensity (TMI) surveys covering parts of the Delamerian Orogeny in South Australia. All calculations were completed using the magnetic inversion tool contained within ModelVision using the “sweet-spot” traverse inversion depth-estimation technique.

Download the cover thickness and magnetic source depth modelling data packages

Delamerian AusLAMP resistivity model

AusLAMP resistivity model image The first 3D electrical resistivity model to image the entire Curnamona Province and most of the onshore extent of the Delamerian Orogen crosses the geographical state borders between South Australia, New South Wales and Victoria. Signatures from past tectono-thermal events can be retained in the lithosphere for hundreds of millions of years. Magnetotelluric (MT) methods image the deposited conductive mineralogy as electrically conductive pathways. MT also images regions of different bulk conductivity and can help to understand the continuation of crustal domains down into the mantle, and address questions on the tectonic evolution of Australia.

Download the AusLAMP resistivity model data package

Reprocessed Delamerian  geophysical images

Gravity grids and data image The best available gravity and magnetic data from South Australia, New South Wales and Victoria have been merged into continuous datasets over the Delamerian region, to facilitate geological interpretation, modelling and analysis. A range of transformations have been applied to the merged datasets to expand the range of analyses that can be performed.

Download the geophysical images data package


Back to top

Phase 2 – research and scientific drilling

Stemming from the review, data compilation and release in Phase 1, two geographic regions have been selected to focus geoscientific research programs as well as the Delamerian NDI drilling campaign, in conjunction with the MinEx CRC. The Quondong Vale and Alawoona regions provide a cross-section of geological and geophysical domains within the basement to the Murray Basin. Future work in these regions will provide valuable knowledge on the Delamerian Orogen and its mineral potential.

Download a map of the Delamerian phase 2 focus areas, to be gazetted under section 15 of the Mining Act 1971 after 31 August 2020

Back to top