Neotectonics, geochemical dispersion processes and mineral exploration: linking basement and surface in regions of cover

Abstract

<p>Detection of mineral system footprints in regions under thick cover is challenging. The difficulties are enhanced in regions with low-relief landscapes that are deeply weathered. This is widely the case in Australia where >75% of the surface and subsurface is characterised by transported cover and/or deeply and intensely weathered profiles.</p><p>In a variety of geological-cover contexts, geochemical dispersion/concentration processes within cover units can be particularly efficient. These processes can produce near surface geochemical anomalies in the landscape, which may be expressions of mineral systems within basement units at depth’.</p><p>Basement structures in Earth’s crust are a well-recognised conduit for fluid flow, which can result in the formation of a large variety of mineral deposits (e.g., IOCG, hydrothermal Ni, SEDEX, etc). Therefore, identifying basement structures that may be associated with mineral deposit formation has become an important part of exploration protocols and prospectivity assessments.</p><p>The possible link between neotectonics and geochemical dispersion processes should be carefully considered when studying landscape geochemistry in areas with thick overburden.</p><p>Surface structures linked to principal basement structures which are intermittently reactivated may maintain a direct geochemical link between the basement and the surface. To efficiently resolve basement-derived geochemical signals, soil or surface landscape units should be selectively sampled in relation to these structures.</p><p>This study discusses how in areas of deep cover, neotectonic and/or reactivation surface landscape features have the highest probability to detect deep basement geochemical signatures at surface. This approach may have a critical impact in mineral exploration under cover in similar landscape contexts around the world, such as regions in Australia, West Africa, India, China and Brazil.</p>