Re Sulfides from Zhelos and Tokty-Oi Intrusions (East Sayan, Russia)

Abstract

Re sulfides were discovered in Cu–Ni–platinum-group elements (PGE) ores of the Zhelos and Tokty-Oi intrusions. These intrusions can be considered as products of the mantle superplume responsible for Rodinia’s break-up. The mineral compositions were determined in situ in polished samples. Electron microprobe analyses were mostly consistent with a general formula of (Cu,Fe,Mo,Os,Re)5S8, (Cu,Fe,Mo,Os,Re)4S7, and (Cu,Fe,Mo,Re)S2. One of the major features of Re sulfide from the Zhelos intrusion is its high osmium content. The ΣMe/S ratio for a part of our data is consistent with that of the tarkianite. Re sulfides from the Tokty-Oi have a ΣMe/S ratio similar to those in rheniite or dzeskazganite, but differ from them by the presence of Fe and Cu and the metal-to-metal ratio. The localization of the Re sulfide within the chalcopyrite suggests its crystallization from the residual Cu-rich liquid.