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 has 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, and selected pre-Proterozoic basins and sediment packages.

These maps will be 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 will be incorporated with minimum modification.

The aim of this work is to cover all of northern Australia starting with the Tennant Creek to Mt Isa focus area of the Exploring for the Future program.

Current work is in the focus area of the Exploring for the Future program and extends to cover the entire Northern Territory. Geoscience Australia has plans to produce solid geology maps for extensive areas of northern Australia in coming years.

Progress

The solid geology of the Tennant Creek to Mount Isa (TISA) area, which consists of four layers, namely: Mesozoic, Paleozoic, Neoproterozoic and Pre-Neoproterozoic, can be accessed here. This is the first staged release of Geoscience Australia’s time-based solid geology mapping program. Updates will be announced as the solid geology mapping program progresses across Northern Australia. 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.

Outputs

Public release of solid geology maps over the Exploring for the Future program focus area are expected to be released mid-March 2018 at the Annual Geoscience Exploration Seminar in Alice Springs.

Collaborations

This work is 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.