Solid Solutions of Karelianite and Eskolaite (Slyudyanka Complex, Southern Baikal Area): Genesis and a Possible Petrogenetic Indicator

Abstract

Abstract —A continuous solid-solution series between the end-members eskolaite (98 wt.% Cr2O3) and karelianite (93 wt.% V2O3) has been revealed in Cr–V-bearing rocks of the Slyudyanka metamorphic complex. Chromium and vanadium oxides crystallized as karelianite-eskolaite minerals during regional high-temperature prograde (granulite facies) metamorphism and participated in the formation of other Cr–V and Cr–V-bearing phases. Ferrian karelianite (up to 12 wt.% Fe2O3) and three-component solid solutions Esk12–50Kar45–60Hem6–30 occur in metamorphic rocks that have particular protolith compositions (Fe–Kar) and in later metasomatic rocks ((Cr, V, Fe)2O3). Natural eskolaite and karelianite are discussed in terms of paragenesis, and their crystallization conditions are compared with the conditions of their laboratory synthesis.