Preliminary study of the source of base metals in MVT deposits of the Canning Basin, Western Australia

Abstract

New bulk chemical and mineralogical data for unmineralized sediments and a review of published lead isotope and permeability/porosity data indicate that Carboniferous and Devonian feldspar-rich sandstones and siltstones are the most likely reservoirs for one-forming brines and metals in the eastern Canning Basin, Australia. The Anderson Formation and Tandalgoo Sandstone are characterized by extreme depletion in Pb and Zn relative to Cu. Conversely, limestones and dolomites of the Devonian and Carboniferous rift-fill are enriched in Pb and Zn relative to Cu. This enrichment, is interpreted to be due to hydrothermal processes, suggesting that carbonate rocks of the Carboniferous-Devonian rift-fill sequence could be targeted for MVT deposits. Furthermore, anomalous Au, As and Sb in limestone of the Pillara Formation suggests that the possibility of Carlin-style gold deposits merits some consideration.