Y- REE Mineralization in Biotite-Arfvedsonite Granites of the Katugin Rare-Metal Deposit, Transbaikalia, Russia

摘要

This paper reports on the results of studies of the carbonate-fluoride isolations with extremely high Y and REE concentrations from biotite-arfvedsonite granite of the Katugin rare metal deposit. We obtained the chemical data on that minerals that compose these isolations-gagarinite-(Y), tveitite-(Y), fluocerite-(Ce), bastnaesite, and fluornatropyrochlore. A carbonate-fluoride globule with a well-preserved crystallization order was revealed in quartz of the host granite. This finding might be evidence of silicate-fluorine immiscibility suggested before for the Y-REE isolations in the Katugin granites. We assumed that the fluoride melt occurred at the magmatic stage of the formation of biotite-arfvedsonite granite, which resulted in depletion of the host granite with fluorine and the redistribution of the REE and Y in the fluoride salt melt.