Depth to basement mapping in Mount Isa using 2D MT constrained inversions

Many Australian metallogenic provinces are buried under thick post-mineralization cover. Imaging the depth to prospective basement in this type of geological environment is challenging and improving the reliability of the geophysical images requires incorporating constraints within the geophysical data inversions. In this study, we propose to derive structural depth constraints using a probabilistic magnetotelluric (MT) data driven workflow, to constrain a deterministic 2D MT inversion. The workflow is applied to a profile in the Mount Isa region in Queensland. The results show that a geologically realistic model with sharp resistivity boundaries associated with the depth to basement transition can be recovered even in presence of a conductive sedimentary cover of thickness greater than 500 meters.
Open-Access Online Publication: May 31, 2023