Controls on mineral endowment in the Georgetown Inlier, northeastern Australia: implications of tectono-magmatic evolution and magma fertility

Abstract

ABSTRACT The Georgetown Inlier and adjacent Croydon Province form the easternmost exposure of Proterozoic crust in the North Australian Craton and host diverse mineral systems ranging from the Palaeoproterozoic to the Permian. Despite this long-lived tectono-magmatic history, their overall metal endowment is modest compared with the Mount Isa, Curnamona, and Gawler provinces. This study synthesises geological, geochronological, geochemical, and mineral deposit data to evaluate the controls on mineral endowment. Mineralisation occurred episodically and includes Proterozoic IOCG-style Cu and Pb–Zn–Ag deposits, Mesoproterozoic pegmatite-hosted Li and high-purity silica systems, Siluro–Devonian intrusion-related Au, and Carboniferous–Permian porphyry, epithermal Au–Ag, and reduced Sn–W–Mo–U systems. Early Proterozoic mineralisation was variably overprinted by Mesoproterozoic metamorphism and later modified by Phanerozoic magmatism. Integration of igneous geochemistry with Rhyolite-MELTS modelling indicates that magma fertility was spatially and temporally restricted. Predominantly reduced, peraluminous Proterozoic magmatism, together with relatively thin lithosphere and repeated thermal reworking, limited both the formation and preservation of giant ore deposits. Nevertheless, the region remains prospective for pegmatitic Li–Cs–Ta, high-purity silica, and porphyry Cu–W–Mo–U mineral systems within its tectono-magmatic framework.