Metallogenic episodes of the Tasman fold belt system, eastern Australia

Abstract

Precise dating of alteration minerals and host rocks to Au and base metal deposits in the Tasman fold belt system, eastern Australia, has established a number of distinct metallogenic epochs which correspond to episodes of magmatism or to deformation events. Base and precious metal mineralization was emplaced in the Mount Read Volcanics, Tasmania, at about 500 Ma, and other hydrothermal or deformational events may have occurred in the Hellyer deposit between approximately 480 and 440 Ma. Copper and Au mineralization was emplaced in the Lachlan fold belt, New South Wales, at about 440 Ma, and appears to be related to the end stages of Ordovician magmatism that spans a period from approximately 480 through to 440 Ma. Gold deposits (+ or - base metals), which formed in New South Wales and Tasmania at about 420 to 380 Ma, are essentially coeval with deformation and/or are broadly related to Siluro-Devonian magmatism that largely occurred from about 420 to 390 Ma. Gold mineralization in the Anakie inlier, northeast Drummond basin, North Queensland, was essentially coeval with the emplacement of the host Drummond sequence at about 350 Ma.