Rare earth minerals in ores of the malmyzhskoe gold-copper-porphyry deposit (Khabarovsky krai)

Composition and typomorphic features have been studied for rare earths-bearing minerals from the central part of the Malmyzhskoe gold-copper-porphyry deposit. This deposit is located in the Russian Far East, approximately 220 km northeast from Khabarovsk city. The deposit porphyry clusters occur as diorite and granodiorite stocks of Cretaceous age intruding the hornfels-altered siltstone and sandstone sedimentary sequences. The rare earth mineralization in ores and altered host rocks is represented by anhydrous phosphates (monazite, xenotime, REE -bearing apatite), silicates (allanite, huttonite), fluorocarbonates (synchysite) and oxides (davidite). These minerals occur there as individuals, but also they shows reactionary relations between them and ore minerals in altered rocks. It means that rare earth minerals in the central part of the Malmyzhskoe deposit participated actively in metasomatic processes, and likely they have a hydrothermal origin.