Characteristics of porphyry Cu deposits and their potential as exploration targets in South Australia / Характеристики медно-порфировых месторождений и их потенциал как объектов для геологоразведочных работ в Южной Австралии

Porphyry Cu deposits are typically large tonnage (>150 Mt) and low grade (<1%) hypogene deposits (Holliday and Cooke 2007, Sillitoe 2010b). Porphyry Cu deposits are unified by close spatial, temporal and genetic associations between subvolcanic porphyritic intrusive complexes and hypogene mineralisation, with hydrothermal alteration mineral assemblages that occur in and around them (Holliday and Cooke 2007). Hydrothermal alteration associated with porphyry Cu deposits is large volume (10>100 km3), centred on porphyry Cu stocks, plutons or dykes that form above larger batholiths at 6–10 km depth (Sillitoe 2010b). The potential for giant porphyry Cu deposits (i.e. several deposits >1 billion tonnes @ 0.5% Cu, e.g. Bingham Canyon, Utah; Collahuasi, Chuquicamata, La Escondida, El Teniente, Chile; Tables 1–3) makes them valuable exploration targets (Richards 2003). Porphyry Cu deposits are significant in the world’s metal supply, accounting for nearly three-quarters of the world’s supply of Cu, in addition to other metals such as Mo (approximately half of the world’s supply); Au (approximately one-fifth), most of the Re, and minor amounts of other metals such as Ag, Pd, Te, Se, Bi, Zn and Pb (Sillitoe 2010b). Porphyry deposits are most commonly discovered in continental arcs and oceanic arcs of Cenozoic and Quaternary age but have also been discovered in ancient fold belts (Cooke et al. 2005). Porphyry Cu deposits have been generated worldwide since the Archean, although younger examples, Mesozoic to Cenozoic in age are the most abundantly preserved, which may be simply a consequence of younger terranes being less eroded. <...>