Origin of corundum rocks of the Belomorian mobile belt: Evidence from noble gas isotope geochemistry

The noble gas isotopic composition is studied in gas-liquid microinclusions from minerals of the corundum-bearing and host rocks of the Khitoostrov occurrence, North Karelia. It was established for the first time that fluid participating in the formation of rocks with anomalous oxygen isotopic composition is devoid of an atmospheric component, while helium and neon show significant fractionation relative to argon. The formation of rocks with extremely light oxygen isotope composition was related to the effect of endogenous fluid.