Layered geology mapping - accelerating resource discovery in the 21st century

Accurate mapping of Australia’s rocks is the foundation of managing our mineral, energy and groundwater resources. Producing these maps has been a core objective of public geoscience organisations for over a century and gave rise to what is known as a layered or ‘solid geology’ map. Historically, solid geology describes a map showing the rocks exposed at the surface or covered by superficial sediments and regolith (unconsolidated rocks, sands and other loose material).?

With about 80% of Australia’s surface covered by sediments and regolith, mapping of the rock layers, or stratigraphy, through this cover is a major challenge. Despite this difficulty, the need to identify groundwater resources and critical minerals such as rare earth elements have made mapping of stratigraphy increasingly important.?

In 2024, we released the national chrono-lithostratigraphic maps of 5 geological eras, at a scale of 1:1,000,000. This is a world-first for continental mapping of geology and a quantum leap from the previous national surface geology map of Australia, released in 2012. ?

Under the recently concluded Exploring for the Future program we adopted a chronostratigraphic approach, breaking down and mapping geology based on 5 major eras, ranging in age from the Cenozoic (younger than 66 million years ago), through Mesozoic, Paleozoic, Neoproterozoic and finally a layer of pre-Neoproterozoic (older than 1,000 million years ago).?

For example, the Mesozoic time slice (or layer) shows Mesozoic rocks and structural features that would be present at surface if all overlying Cenozoic units were removed. The pre-Neoproterozoic time slice shows what would be visible if all Neoproterozoic, Paleozoic, Mesozoic and Cenozoic units were removed.?

Mapping geology at this level of detail required a high level of expertise to interpret and integrate multiple data sources, including regional magnetics and gravity, logs of drill holes and interpretation of reflection seismic. Information about concealed sedimentary layers and other major rock units derived from AusAEM, the national airborne electromagnetic survey, was also a key source of information.?

Production of the maps was completed in close collaboration with state and territory geological surveys, who have long histories of solid geology mapping within their own jurisdictions. Collaboration enabled the sharing of expertise and also helped to resolve discrepancies at state and territory boundaries to create a seamless national product.?

The new chrono-lithostratigraphic layers (available via our Data Discovery Portal) are an important foundation for mapping Australia’s mineral, energy and groundwater resource potential and have already been used to underpin exciting products for industry. For example, the iron oxide-copper-gold (IOCG) mineral potential map, released in 2024, used features extracted from the national solid geology maps, which proved to be some of the most important inputs in the assessment. ?

The new chrono-lithostratigraphic layers, are an important component of Resourcing Australia’s Prosperity, the Australian Government’s 35-year, $3.4 billion precompetitive geoscience initiative. Currently in the detailed planning and consultation phase, the goal of the initiative is to accelerate the discovery of critical minerals and other resources to support Australia’s net zero transition and enable responsible resource management.?

In partnership with Commonwealth and state and territory governments, we will comprehensively map Australia’s onshore resource potential for critical minerals, strategic materials, geological storage of hydrogen and carbon dioxide, and all of Australia’s groundwater systems. In the offshore,?the initiative will assess suitability for offshore renewable energy?and geological storage. ? ?

We are attending events and running online consultation sessions with key stakeholders and collaborators across industry, government, and academia, to shape planning for Resourcing Australia’s Prosperity. All feedback gathered from the consultations will be considered in the planning of the first 10 years of the initiative, to ensure that our precompetitive geoscience and its application aligns with a broad range of needs and objectives. ?? ?

To help support this consultation process we are seeking input from everyone interested by completing a?short online survey (closing 1 November 2024).

If you have any questions about Resourcing Australia’s Prosperity or would like to RSVP for an online consultation session, please email [email protected]? ?