Regolith-landform processes and geochemical exploration for base metal deposits in regolith-dominated terrains of the Mt Isa region, northwest Queensland, Australia

摘要

The regolith in the Mt Isa region of Queensland consists of a variety of saprolites and duricrusts developed on Proterozoic basement rocks and fresh to weathered Mesozoic, Tertiary and Quaternary cover, all of which has impeded base metals exploration. This paper presents an overview of some of the regolith-geochemical work conducted in the Mt Isa region as part of an industry-supported three year CRC LEME/AMIRA Project. A complex weathering and landscape history has produced a landscape of (a) continuously exposed and exhumed basement rocks that have undergone varying intensities of weathering and partial stripping; (b) weathered and locally eroded Mesozoic cover sequences and (c) areas with younger transported cover concealing basement and Mesozoic cover. Various regolith sample media have been evaluated at a number of prospects and deposits which represent different regolith-landform terrains and landscape history. Geochemical dispersion processes and models are presented and false anomalies explained.