METALLOGENIC EPISODES OF THE TASMAN FOLD BELT SYSTEM, EASTERN AUSTRALIA

Precise dating of alteration minerals and host rocks to Au and base me tal deposits in the Tasman fold belt system, eastern Australia, has es tablished a number of distinct metallogenic epochs which correspond to episodes of magmatism or to deformation events. Base and precious met al mineralization was emplaced in the Mount Read Volcanics, Tasmania, at about 500 Ma, and other hydrothermal or deformational events may ha ve occurred in the Hellyer deposit between approximately 480 and 440 M a. 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 en d stages of Ordovician magmatism that spans a period from approximatel y 480 through to 440 Ma. Gold deposits (+/- base metals), which formed in New South Wales and Tasmania at about 420 to 380 Ma, are essential ly coeval with deformation and/or are broadly related to Siluro-Devoni an magmatism that largely occurred from about 420 to 390 Ma. Gold mine ralization in the Anakie inlier, northeast Drummond basin, North Queen sland, was essentially coeval with the emplacement of the host Drummon d sequence at about 350 Ma.