Controls on Skarn Mineralization and Alteration at the Cadia Deposits, New South Wales, Australia

Mechanisms of iron oxide transformations in hydrothermal systems

“…We propose that transformation mechanisms of iron oxides revealed in this study are applicable to various natural and laboratory systems involving low-temperature hydrothermal fluids, which were also discussed partly in Otake et al (2007). Barnes, 1983;Zierenberg and Shanks (1983); Rona, 1984), volcanogenic massive sulfide (Callow, 1967;Westendorp et al, 1991) and oxide (Davidson, 1992;Duhig et al, 1992) deposits, magnetite skarn-deposits (Buseck, 1966;Zü rcher et al, 2001;Forster et al, 2004), Olympic Dam-type (Fe oxide-Cu-Au-Co), porphyry Cu deposits (Gow et al, 1994;Lynch and Ortega, 1997;Kolb et al, 2006), and banded iron formations (BIFs; Ewers and Morris, 1981;LaBerge et al, 1987;Pecoits et al, 2009). Some authors questioned whether redox equilibrium was attained between the iron oxides, and whether enough oxidants/reducants were present during the replacement of magnetite to hematite/ hematite to magnetite.…”

The origin and evolution of skarn-forming fluids from the Phu Lon deposit, northern Loei Fold Belt, Thailand: Evidence from fluid inclusion and sulfur isotope studies

“…Field observations and fluid inclusion and sulfur isotope studies indicate that the Phu Lon skarn deposit was formed during multiple geological events similar to other Cu-Au skarn systems (e.g., Einaudi et al, 1981;Shelton, 1983;Meinert et al, 1997;Forster et al, 2004;Fig. 9).…”

Geology, mineralization, and fluid inclusion characteristics of the Chorukh-Dairon W–Mo–Cu skarn deposit in the Middle Tien Shan, Northern Tajikistan

“…Remarkably, scapolite is typically not abundant in tungsten skarns, with the notable exception of the Kensu deposit (Soloviev, 2011), located in the same Tien Shan province. However, scapolite is a common mineral in Fe-Cu and Au skarns (Pan et al, 1994;Pan, 1998), particularly in those related to shoshonitic suites (e.g., Forster et al, 2004), and also in the iron oxide hosted copper-gold (IOCG) deposit family (e.g., Soloviev, 2010), where scapolite is closely associated with albite, thus constituting the sodic (or sodic-calcic) alteration assemblage (Lang et al, 1995), similarly to the mineral paragenesis at the hydrosilicate stage at Chorukh-Dairon. Sourcing of Na, together with Ca, from a magmatic fluid is often considered (Lang et al, 1995;Pollard, 2001), occurring possibly due to small shifts away…”