Fluid Regime of Crystallization of the Calcite-Quartz Carbonatitoids of the Murun Massif
I.A. Sotnikova1, A.A. Borovikov2, T.B. Kolotilina1, N.V. Alymova1
1Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
2V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences
Novosibirsk, Russia
Keywords: Сarbonatitoids, torgolites, fluid and melt inclusions, thermobarogeochemistry, quartz, dalyite, Murun massif
Abstract
Primary melt and fluid inclusions in quartz and dalyite of calcite-quartz carbonatitoids of the Murun massif have been studied. They contain CO2, N2, CH4, C2H6, C3H8, H2, and H2S as well as sulfates and hydrocarbonates as solid daughter phases. The inclusion solutions contain HS- and chlorides. In addition, disordered carbon and bitumen are present. It is concluded that the magmatic fluid phase that was in equilibrium with quartz was characterized by a predominantly H2O-CO2-H2S composition and a reduced state. This explains the appearance of sulfides at the magmatic stage of crystallization of calcite-quartz carbonatitoids of the Murun massif. We substantiate the hypothesis that the sulfates, hydrocarbons, and H2 detected in the inclusions form at decreasing temperature as a result of shift of the redox equilibrium.
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