The electrical resistivity model of the Australian lithosphere

We present a new 3D electrical resistivity model of the entire Australian subcontinental lithosphere, which we call the Australian Multiscale Model of Electrical Resistivity (AusMMER). The AusMMER is derived from the joint inversion of magnetotelluric (MT) responses from the currently available part of the AusLAMP and state arrays, geomagnetic responses from observatories, and the legacy Australia-Wide Array of Geomagnetic Stations (AWAGS). In total, we invert plane-wave transfer functions from 1,394 MT sites and 60 geomagnetic stations at periods between 10 and 10,000 s. The inversion uses a distributed 3D finite-element electromagnetic solver that operates directly in the spherical frame and supports multiscale, locally refined meshes. This approach allows us to integrate heterogeneous datasets and recover a coherent 3D electrical resistivity model spanning the lithosphere and the uppermost asthenosphere. The imaged anomalies align with major tectonic units and their boundaries, with some prominent features extending into the lithospheric mantle, while others remain confined to the crust. These relationships provide new insights into crust–mantle architecture and the role of deeper mantle processes in shaping Australia’s tectonic domains and continent accretion. We further show that many prominent ore deposits spatially coincide with lithospheric resistivity anomalies, providing new insights into the crust–mantle controls on mineralization. Finally, the AusMMER provides the baseline for quantifying the Geomagnetically Induced Currents during geomagnetic storms.