Abstract
The aim of this study is to conduct an in-depth analysis of data on the genesis of pegmatite deposits of the Kalba-Narym rare metal belt, features of rare metal mineralization. The research methodology includes the analysis of existing information on the study of geology and structural-tectonic conditions of the formation of rare metal deposits within the central part of the Kalba-Narym batholith. Field studies, sampling (more than 40 samples), and study of the mineralogical composition of pegmatites and host rocks using optical microscopy and transmission electron microscopy were carried out. The results of the work showed that the model of the formation of rare metal pegmatites is genetically related to primary granite-forming melts and fluids enriched in ore-bearing gas-liquid inclusions. The deposits were formed as a result of separation of fluid-saturated solutions (H2O, F, Cl, B, SO2, Ta, Be, Li, etc.) at the final stage of development of the granite massif under nonequilibrium conditions of pressure and temperature (P-T), which led to the concentration of rare-metal mineralization. It was established that the ore formation process is staged and is characterized by intensive metasomatic changes (microclinization, albitization, greisenization, silicification, etc.) and the formation of various mineral associations. New data on the mineral composition of pegmatite ores on both macro- and microscales were obtained using scanning electron microscopy and inductively coupled plasma mass spectrometry.