The acquisition and interpretation of the deep crustal seismic line 13GA-EG1 has allowed a new 3D model to be constructed for the western Gawler Craton. The new 3D model expands on the Eastern Gawler IOGC / Woomera Prohibited Area model, which sits to the north and east of this seismic line. Interpretations used to construct this model were derived from a cross-border collaborative work program between the Geological Survey of South Australia, the Geological Survey of Western Australia and Geoscience Australia, initiated by the collection of seismic line 13GA-EG1. This is the first of three models which will cover the length of the seismic line 13GA-EG1; the others being the Albany-Fraser Orogen model in Western Australia and the Coompana model which straddles the WA/SA border. These are being worked on and will be published in the coming years to produce a continuous crustal architecture and density model between the Gawler and Yilgarn Cratons.

This model was produced by The South Australian Centre for Mineral Exploration Under Cover (CMXUC), a collaborative research initiative of the Government of South Australia and the University of Adelaide. In this area, basement is buried beneath Neoproterozoic-Recent cover, of the Eastern Officer, Arckaringa and Eromanga Basins. The depth to basement horizon, shows the complex geometry of the Munyarai Trough which forms a foreland to the uplifted Musgrave Block; the Marla Overthrust Zone and Ammaroodinna Ridge which were uplifted after the deposition of Cambrian to Silurian sedimentary rocks; the Middle Bore Fault Zone which was last active during deposition of the Arckaringa Basin and the Wintinna Trough. Large potential field anomalies have been observed in the Marla Region of Northern South Australia and have been used to define the northern limit of the Gawler Craton. This project’s aim was to model the source of those anomalies in order to understand the sources of those anomalies.