Lithogeochemical constraints on the host rock, hydrothermal alteration and weathering of the Groundrush gold deposit

摘要

Lithogeochemical research at the Groundrush gold deposit, Tanami region, Northern Territory, has identified new lithologies and provides a new understanding of the hydrothermal alteration, metamorphism and weathering processes that have affected the suite of metamorphosed igneous host rocks. Metamorphosed hornblende–chlorite–plagioclase-bearing mafic–intermediate intrusive rocks were classified, using conserved constituents, as dolerite and previously unrecognized basaltic andesite and diorite, the last of which hosts Au mineralization. The diorite forms a steeply dipping dyke, whereas the dolerites are sills intruding clastic sedimentary rocks.