Platinum-group element geochemistry used to determine Cu and Au fertility in the Northparkes igneous suites, New South Wales, Australia

Prospect for gold and other precious metals in meta-igneous rocks of Sri Lanka: implications from geochemistry

“…3b), in which all the samples except for garnetiferrous charnockites from the HC show a negative correlation. This negative correlation shown by the Pt/Pd against MgO is a solid evidence for segregation of sulphide melts from respective magmas (Park et al, 2013(Park et al, , 2015Hao et al, 2017;Lowczak et al, 2017). The geochemical trend shown by Au/Pt of the studied samples is also more-or-less similar with that of the Pt/Pd (Fig.…”

“…Most of the precious metal deposits of the world are found associated with very old volcanic rocks (Proterozoic to Precambrian), and occur in melt-crystallized veins (Boyle, 1979). Studies have found that water-rich arc magmas may play an important role in the formation of these metals in rocks (McInnes et al 1999;Sillitoe, 2010;Hao et al 2017). However, only a limited number of arc igneous suites host economically exploitable large precious metal deposits due to certain prerequisites.…”

“…On the other hand, studies on igneous rocks (e.g. Campbell and Barnes, 1984;Setiabudi et al 2007;Park et al, 2013;2015;Cocker et al, 2015;Hao et al, 2017) have shown that Au and PGE behave in an immobile manner, which facilitates formation of Au-PGE enrichments in rocks crystallizing from magma. Therefore, constraints on chalcophile element geochemistry in igneous/meta-igneous rocks can provide important implications on magma evolution.…”

Platinum-Group Element Geochemistry of the Escondida Igneous Suites, Northern Chile: Implications for Ore Formation

“…Porphyry deposits, the world's most important source of Cu, Au and Mo, are generally associated with continental or oceanic arc magmas of intermediate to felsic composition (Burnham, 1979;Richards, 2003;Cooke et al, 2005;Sillitoe, 2010). Processes that control the formation of porphyry mineralization include: the metal endowment of the primitive magma (McInnes et al, 1999;Mungall, 2002;Richards, 2011a;Audétat and Simon, 2012); the oxidation state during magmatic evolution (Candela, 1992;Richards, 2003Richards, , 2015Sillitoe, 2010); the water content of the magma (Burnham, 1979;Candela, 1992;Richards, 2003Richards, , 2011bRichards, , 2012; the timing of sulfide saturation relative to volatile exsolution (Richards, 2003;Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018); the metal content of the magma at the time of volatile exsolution (Jenner et al, 2010;Park et al, 2015); and the efficiency of the hydrothermal fluid, released by the magma, to dissolve, transport, and precipitate ore metals (Cline and Bodnar, 1991;Candela and Piccoli, 2005;Wilkinson, 2013). In this paper, we focus on the petrogenesis and evolution of porphyry magma systems, emphasizing the relative timing of sulfide and volatile saturation and their roles in determining magma fertility.…”

“…In this paper, we focus on the petrogenesis and evolution of porphyry magma systems, emphasizing the relative timing of sulfide and volatile saturation and their roles in determining magma fertility. Recent studies (Cocker et al, 2015;Hao et al, 2017;Lowczak et al, 2018) have used platinum-group element (PGE) geochemistry to argue that the relationship between sulfide and volatile saturation plays a critical role in determining magma fertility (i.e., the potential of a given magma system to produce a hydrothermal ore deposit). The results of initial studies (Cocker et al, 2015;Hao et al, 2017) are consistent with the hypothesis that if fluid exsolution occurs before, or shortly after sulfide saturation, Cu and/or Au will be available to enter the hydrothermal fluid, potentially resulting in the formation of a porphyry Cu ± Au deposit (Spooner, 1993).…”