The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a national initiative charged with mapping the electrical resistivity structure of the Australian lithosphere. AusLAMP data acquisition took place across Tasmania in 2016 and was a collaborative effort involving staff and students from UTAS, Geoscience Australia, Mineral Resources Tasmania and the University of Adelaide. Through 2018 the AusLAMP data set was used to generate Tasmania-wide and regional 3D electrical resistivity models of the subsurface. In 2019 the computational phases of the project concluded with two further major results: 1) geoelectric transects across the west and northwest of Tasmania and 2) a collaboration with John Bishop resulting in an improved geoelectric model for the midlands of Tasmania that combines AusLAMP and industry data from KUTh Energy Ltd. The Tasmanian midlands is prospective for geothermal energy and the new 3D images will inform the next phase of data collection for this resource.

Final interpretation, including integration with updated geophysical data sets for Tasmania, is now complete. AusLAMP resistivity models yield insights into the regional-scale resistivity structure for the Tasmanian crust and uppermost lithospheric mantle. The models confirm the presence of the Tamar Conductivity Anomaly as a shallow- to mid-crustal arcuate structure between the Tamar and Coal River valleys, coincident with the inferred boundary between the uniformly resistive East Tasmania Terrane and the more electrically complex West Tasmania Terrane. In the mid- to upper-crust, highly resistive zones of the model are spatially correlated with areas of voluminous Devonian granite intrusion (Eastern Tasmania, South West Cape and the central west). Areas of anomalously low resistivity at this depth are spatially correlated with outcropping Cambrian metamorphic complexes bounding the Dundas-Fossey Trough.

Advanced 3D visualisation was employed to investigate relationships between the newly determined conductivity structures at depth, and crustal architecture such as granite bodies. This will inform understanding of tectonic evolution and both mineral and geothermal prospectivity for Tasmania.

The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a national initiative charged with mapping the electrical resistivity structure of the Australian lithosphere. AusLAMP data acquisition took place across Tasmania in 2016 and was a collaborative effort involving staff and students from UTAS, Geoscience Australia, Mineral Resources Tasmania and the University of Adelaide. Through 2018 the AusLAMP data set was used to generate Tasmania-wide and regional 3D electrical resistivity models of the subsurface. The computing was impacted by flooding (May 2018) that affected the UTAS high-performance computing infrastructure.

Final interpretation, including integration with updated geophysical data sets for Tasmania, is now underway. AusLAMP resistivity models yield insights into the regional-scale resistivity structure for the Tasmanian crust and uppermost lithospheric mantle. The models confirm the presence of the Tamar Conductivity Anomaly as a shallow- to mid-crustal arcuate structure between the Tamar and Coal River valleys, coincident with the inferred boundary between the uniformly resistive East Tasmania Terrane and the more electrically complex West Tasmania Terrane. In the mid- to upper-crust, highly resistive zones of the model are spatially correlated with areas of voluminous Devonian granite intrusion (Eastern Tasmania, South West Cape and the central west). Areas of anomalously low resistivity at this depth are spatially correlated with outcropping Cambrian metamorphic complexes bounding the Dundas-Fossey Trough.

Advanced 3D visualisation is being employed to investigate relationships between the newly determined conductivity structures at depth, and crustal architecture such as granite bodies. This will inform both mineral and geothermal prospectivity for Tasmania.

The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a national initiative charged with mapping the electrical resistivity structure of the Australian lithosphere. AusLAMP data acquisition took place across Tasmania in 2016 and was a collaborative effort involving staff and students from UTAS, Geoscience Australia, Mineral Resources Tasmania and the University of Adelaide.

In 2017 the AusLAMP dataset was used to generate Tasmania-wide 3D electrical resistivity models of the subsurface. This extremely computationally intensive process required the use of high-performance computing infrastructure at the University of Adelaide as well as the Tasmanian Partnership for Advanced Computing (TPAC). Modelling is now complete and current efforts are focussed on integrated geophysical interpretations of Tasmania’s deep electrical structure.

AusLAMP resistivity models yield insights into the regional-scale resistivity structure for the Tasmanian crust and uppermost lithospheric mantle. The models confirm the presence of the Tamar Conductivity Anomaly as a shallow- to mid-crustal arcuate structure between the Tamar and Coal River valleys, coincident with the inferred boundary between the uniformly resistive East Tasmania Terrane and the more electrically complex West Tasmania Terrane. In the mid- to upper-crust, highly resistive zones of the model are spatially correlated with areas of voluminous Devonian granite intrusion (Eastern Tasmania, South West Cape and the central west). Areas of anomalously low resistivity at this depth are spatially correlated with outcropping Cambrian metamorphic complexes bounding the Dundas-Fossey Trough.

At uppermost mantle depths Tasmania’s electrical resistivity structure splits into two distinct regions; a low resistivity region in the west and a high resistivity region in the east. As electrical resistivity is largely controlled by volatile content at this depth, where greater volatile content reduces resistivity, the relative difference in electrical resistivity is potential evidence for higher degrees of mantle depletion in the East Tasmania Terrane.

A major field geophysical program was undertaken during the year in collaboration with Mineral Resources Tasmania, the University of Adelaide and Geoscience Australia. Long period magnetotelluric (MT) data recordings were made at locations across Tasmania and broadband MT transects completed in the west and north of the state. The aim is to produce a 3D map of the electrical resistivity of the lithosphere beneath Tasmania to inform understanding of Tasmania’s tectonic evolution, and provide backbone information for mineral explorers. Field work was led by PhD student Thomas Ostersen, with staff and students from the participating institutes contributing many field-days to the effort – often working through severe conditions, including bushfires and snow storms.