Geoscience Australia's Magnetotelluric program and data release

Geoscience Australia, in partnership with State and Territory Geological Surveys and research organisations, has applied the magnetotelluric (MT) method to image the resistivity structure of the Australian continent over the last decade. Data have been acquired at nearly 5000 stations through the collaborative national AusLAMP survey and regional MT surveys. The data provide valuable information for multi-disciplinary interpretations that incorporate various datasets. Most of these MT data have been released to the public. To date, AusLAMP has been completed ~30% of the national coverage. Data have been acquired at nearly 1000 stations. This pre-competitive dataset will be an essential input to Geoscience Australia’s Exploring for the Future program as well as a valuable resource for researchers to reconstruct the tectonic evolution of the Australian continent. The regional MT surveys have been undertaken across potential mineral/energy provinces and greenfields areas in the Australia continent. A number of regional surveys have been completed recently. The MT data from the poorly understood Southern Thomson Orogen and Coompana region have improved understanding of cover thickness, sub-surface geology, and crustal architecture. The data reduce the uncertainty associated with intersecting the targeted stratigraphy for the pre-competitive stratigraphic drilling program. Comparison with drill-hole information indicates that the technique is capable of identifying major stratigraphic structures and providing cover thickness estimates with reasonable accuracy in regions where there is little surface outcrop and thick cover sequences. The MT data from the Mount Isa inlier in northern Australia provide new insights into basement architecture, the crustal architecture and resource potential in this region. The data reveal some crustal-scale conductivity anomalies which correspond to known major crustal boundaries and faults. Those faults and boundaries are considered the primary factors in the partitioning of mineralisation in the region, with some conductors in the upper crust coinciding with known mineral deposits. Presented at the 24th Electromagnetic Induction Workshop (EMIW) 13-20 August 2018, Helsingør Denmark (https://emiw2018.emiw.org/)