Relationship between Magmatic-hydrothermal REE mineralization and alkaline magmatism of the Luginn Gol complex, South Mongolia

Abstract

The REE-F carbonate veins are distributed radially around the boundary of Lugiin Gol alkaline complex. This RE mineral bearing breccia vein is composed of broken fragments of fluorite and cemented by fluorite, quartz, RE minerals and small amount of very fine-grained pyrite. RE minerals are composed of synchysite and parasite in brecciate texture with quartz and fluorite.  Fluid inclusions occur in fluorite and are dominated by H2O–NaCl types. Based on mineral assemblage and texture of fluorite-REE veins, it is inferred that a fluorine-bearing hydrothermal activity was associated with REE mineralization.