Unconformity-Related Rare Earth Element Mineral Potential of Australia

Abstract Heavy rare earth elements (HREE) are critical for the transition to net zero in addition to being key to manufacturing defense technologies. Unconformity-related rare earth element (REE) deposits represent an important source of HREE, including key elements such as dysprosium (Dy) and terbium (Tb). Given the strategic importance of these critical minerals to the national economy, a national-scale mineral potential assessment has been undertaken to evaluate the geological potential for unconformity-related REE mineral systems in Australia. Leveraging previous research into the formation of unconformity-related REE mineral systems in Australia, a new model for the mineral system has been developed based on an existing mineral systems framework. The deposits form as a result of crustal- to deposit-scale processes that operate under favorable spatial and temporal conditions. This study demonstrates how a mineral system that has uncertainties regarding its formation can be used as the basis for predictive modeling through the novel use of datasets not typically utilized in broad-scale mineral potential assessments. Both a knowledge-driven and data-driven approach have been used to generate national-scale mineral potential maps that reduce the exploration search space for unconformity-related REE mineral systems in Australia by up to 95%. In addition to predicting known mineralized regions, the model also demonstrates high prospectivity in parts of Australia where no unconformity-related REE mineralization has previously been identified, particularly on the margins of Precambrian basins in Northern Australia, parts of which remain un- or under-explored.