Toward a 3D geological model of Australia.

Abstract:

The frontier of resource exploration in Australia lies beneath ~80% of the continent which is covered by unendowed geological units. To enable exploration through this cover, the development of new mapping methodologies in a 3D space is required to maximise sparsely distributed information and reduce the search space.

3D geological models are data-demanding and rely on robust and harmonised datasets, which can be challenging when crossing states borders. Through the Exploring for the Future program, we adopted an integrated multidisciplinary approach and developed semi-continental scale datasets along with new tools to generate a predictive 3D chronostratigraphic cover model. The developments included: 1) a new seamless solid geology dataset (1:1M scale) extending across three states to map major chronostratigraphic interfaces, i.e. Cenozoic, Mesozoic, Palaeozoic and Neoproterozoic underpinned by the national Australian Stratigraphic Units Database; 2) compilation of depth estimates of the bases of geological eras from multiple datasets, such as Airborne Electromagnetic data (AusAEM survey), reflection seismic, as well as stratigraphic boreholes and magnetic top depth estimates; 3) a new national database (Estimates of Geological and Geophysical Surfaces), to consistently store inferred depth measurements. This platform respects the FAIR principle and allows for uncertainty quantification, track changes as new data becomes available and ensure repeatability of interface modelling; 4) new probabilistic models with a machine learning platform (Uncover ML) to generate predictive depth surfaces that integrate all available depth information and knowledge.

By predicting the spatial extent and depth of key stratigraphic units, this integrated approach allows us to resolve 3D basin architecture and composition. Our approach and outputs provide academia and industry with the necessary spatial controls on subsurface geology to study Earth systems and assess resource potential.

All constraining datasets and results are publicly and freely available through an online portal that allows for 2D and 3D visualisation (www.portal.ga.gov.au), download and analytics for the assessment of mineral potential and delineation of the economic search space through economic modelling.