Depth to pre-Neoproterozoic rocks between Tennant Creek and Mt. Isa – A preliminary model

It is generally accepted that the near surface search space for mineral deposits in Australia and elsewhere in the world has been well explored and the frontier of exploration lies beneath post-mineralisation cover. The Exploring for the Future program aims to unlock this new search space in northern Australia and parts of southern Australia by reducing the technical risk of mineral exploration through the provision of innovative pre-competitive data and information. The first step to de-risk undercover exploration is to simply define the depth to prospective rocks as cover-thickness places first order constraints on the economic search space. With this aim in mind we present a preliminary model of the depth to pre-Neoproterozoic rocks between Tennant Creek and Mt Isa, an area of focused integrated studies of the Exploring for the Future program. This work aims to compliment recent and ongoing mineral potential assessments in this region, which suggest covered pre-Neoproterozoic rocks are prospective for iron oxide-copper-gold and sediment hosted base metal mineral deposits. Our model utilises a dasets of over eight four thousand point estimates of the depth to pre- Neoproterozoic strata from boreholes, reflection seismic profile interpretations and depth to magnetic top estimates mostly sourced from the new Estimates of Geological and Geophysical Surfaces database supplemented by the distribution of pre-Neoproterozoic strata outcrops. These constraints were objectively queried based on their reliability, subsampled at 0.05 degrees and gridded using an adjustable tension continuous curvature-surfacing algorithm. The result shows Palaeozoic cover-thickness generally increases away from outcrops with a notable exception east of Tennant Creek where cover-thickness is typically less than 250 m thick. Fortuitously, this region of shallow cover termed the East Tennant Ridge corresponds with a region recently assess to have potential to host iron oxide-copper-gold mineralisation.