Gold Exploration – Tanami, NT

This series of projects with industry partners investigates the geochemical, mineralogical and sedimentology of the Tanami Group to provide a tool for gold exploration.

The challenge for exploration in the remote Tanami Region, on the border between WA and the NT, is the lack of publicly available geological and geochemical data on the Au-hosting lithologies. The host-rocks are deformed and disjointed sedimentary and volcanic rocks of the structurally complex Granites-Tanami-Orogen. Therefore, defining drilling targets in the 40,000 km2 area is limited to near-mine exploration.

In a series of projects (2017-ongoing), working closely with mineral exploration and mining companies, we used an integrated approach combining geophysical data (magnetics) for structural interpretation with sedimentological facies interpretation and lithogeochemistry across the region. On an ore body scale, we used a range of micro-analytical tools, in order to study the alteration in relation to Au mineralisation. Further, we investigated different sample media, such as historical drill chips, weathered rocks and fresh rocks, for developing and testing the application of the geochemical vectors and variations as a result of weathering.

CSIRO applied geochemical vectoring towards ‘fingerprinting’ the stratigraphy, lithology and alteration related to mineralisation and weathering. The results of the project led to the identification of Au mineralisation associated with particular structures and preferred sedimentary host rocks. We further established a vectoring scheme that allows correlation of stratigraphic units across the region, and definition of alteration related to Au mineralisation. The CSIRO vectoring tool can be adapted specifically towards the region of interest and can be easily used by the mineral exploration industry.

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Publications/reports:

Schmid, S., Davis, J., Evans, N.J., 2021. Geochemical classification of Palaeoproterozoic oceanic volcanic front and backarc basin remnants of the Granites-Tanami Orogen, Australia. Precambrian Research 364, 106362

Schmid, S., Kunzmann, M., McFarlane, H., 2020. Geochemical and sedimentological classification of the Tanami Group, NT, Australia. CSIRO EP207960, 79p. (confidential)

Schmid, S., 2019. Geochemical classification of the Tanami Group stratigraphy in the Bluebush Area, Northern Territory. CSIRO EP19959, 53pp. (confidential)

Schmid, S., Schaubs, P., Miller, J., 2018. Geochemical classification of lithology in the Suplejack area, Tanami Region, NT. CSIRO EP181460, 60 pp. (confidential)