Toward an understanding of the metallogeny of the Tasman fold belt system

      The Tasman fold belt system which makes up the eastern third of the Australian continent is a composite of five Paleozoic orogenic belts. The major mineral provinces of the Tasman fold belt system include provinces of volcanic-hosted massive sulfide deposits, porphyry-granitoid-associated Cu-Au and Au deposits, and granitoid- associated Sn and W deposits as well as provinces of structurally controlled Au and Cu-Pb-Zn deposits. The localization of these provinces is discussed in terms of the nature of the magmatism which is a source of heat and in many cases of fluids and metals, the fracture systems which facilitate the transfer of heat, magmas, and/or aqueous fluids through the crust, and the timing and nature of the stress regimes that permit these fracture systems to be open to fluid flow. The available data indicate that the magmatism of the Cu-Au province of Central-West New South Wales originated in the mantle. Magma systems linked with the deposits of the volcanic-hosted massive sulfide province of western Tasmania, the Sn-W provinces of the Tasman fold belt system, and the porphyry-associated Au deposits of north Queensland had their roots in crust mantle interactions. Crystal fractionation was an important process in the magma systems related to the development of these provinces. A feature of the Tasman fold belt system is the prevalence of major north-south-trending fault systems. More subtle west- northwest structural trends can be appreciated at the continent scale and these Proterozoic structural trends appear to have exerted a significant control on the distribution of major mineral provinces within the Tasman fold belt system. Extension reactivation of basement structures late in tectonic cycles was a major mechanism for creating permeable domains in the upper crust and focusing fluid flow and hydrothermal mineralization. It is suggested that the Permo-Carboniferous Au and Sn provinces of north Queensland developed.

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