RARE-EARTH ELEMENTS IN GRANITES AND MINERALS FROM THE IKH-KHAIRKHAN TUNGSTEN MINING DISTRICT, CENTRAL MONGOLIA

Abstract

The distribution of REE was analyzed in granites from massifs of the Ikh-Khairkhan tungsten mining district and in muscovite and fluorite from metasomatic rocks and mineralized zones of the Ikh-Khairkhan deposit in central Mongolia. The main characteristics of the mineralizing solutions were estimated, based on the study of fluid inclusions in minerals, at T = 180-355°C, P = 520-1050 bar, and a salinity of the solutions equal to 2.5-10.6 wt % equiv. NaCl. The REE distribution in the Ikh-Khairkhan granites is characterized by enrichment in LREE, the absence of Eu anomalies, and a systematic decrease in the concentrations of REE from La to Lu. In contrast to the granites, the high-temperature fluorite of mineralized zones is strongly depleted in LREE and enriched in MREE and HREE in the absence of Eu anomalies.