Solid Geology Mapping

Our understanding of the geological history and resource potential of Australia has been underpinned by over half a century of surface geological mapping. A synthesis of this national geological mapping is represented in the seamless 1:1 000 000 scale Surface Geology of Australia (Raymond et al, 2012). This map shows that approximately 80 per cent of the crystalline basement geology of Australia is covered by a veneer of sediment and regolith (weathered materials). Now, the challenge is to continue to unravel the geology, geological history and the resource potential of Australia beneath this cover.

Geoscience Australia commenced a major program of 'solid geology' mapping of the continent, focused on compiling geological data for key chronostratigraphic surfaces including 'basement' beneath Cenozoic, Mesozoic, Paleozoic, Neoproterozoic and selected pre-Neoproterozoic basins and sediment packages.

These maps have been compiled at an optimal scale of 1:1 000 000 exploiting potential-field datasets, radiometric coverages, seismic profiles, borehole data and regional solid geology compilations. In the interest of efficiency, currently available solid geology compilations at scales between 1:500 000 and 1:2 500 000 were incorporated with minimum modification.

As part of the Exploring for the Future program, Geoscience Australia produced seamless chronostratigraphic solid geology maps that cover all of northern Australia.

Progress

The solid geology dataset, which consists of five layers, namely: Cenozoic, Mesozoic, Paleozoic, Neoproterozoic and Pre-Neoproterozoic, can be accessed through the EFTF portal (https://portal.ga.gov.au/persona/eftf).This is the second staged release of Geoscience Australia’s time-based solid geology mapping program, that followed the first solid geology Tennant Creek to Mount Isa (TISA) dataset (Stewart et al., 2018, https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/116844). This new mapping has also significantly revised the Geological Provinces of Australia, including a recognition that the spatial extent of the highly prospective South Nicholson Basin is almost three times larger than previously mapped (Stewart et al., 2018; https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/116823). Updates will be announced as the revisions progresses across Northern Australia.

Outputs

Public release of solid geology maps over the Exploring for the Future program focus area were released mid-March 2020 at the Annual Geoscience Exploration Seminar in Alice Springs.

Collaborations

This work was led by Geoscience Australia with close collaboration with state and Territory geological surveys by building on their outcrop and solid geology mapping work and expertise.