Ways of Rare Earth Elements Migration and Transportation to the coals of the Shubarkol Deposit

Abstract

The article presents the results of studying the mineralogical and geochemical features of coals and clay interlayers of the Shubarkol deposit. There were analyzed 71 samples of clay layers and 49 samples of coal using the instrumental neutron activation analysis (INAA), powder X-ray diffractometry, and scanning electron microscopy. A comprehensive analysis of the geochemical and mineralogical characteristics of coals and their enclosing clay interlayers was carried out. A variety of geochemical criteria made it possible to establish the facts of the rare earth elements (REE) migration, and the latest data of mineralogy made it possible to establish the ways of their transportation to the paleobasin in the syn- and epigenetic periods of the Shubarkol deposit formation. The data of the paleoclimate and water composition of the paleobasin of peat formation are presented for the first time. Among other things, the analysis made it possible to identify a number of independent sources and various mechanisms of REE accumulation in the sediments of the Shubarkol deposit. The main patterns of the REE distribution that are expressed in the predominance of light lanthanides over heavy lanthanides, were established, and the role and composition of the rocks surrounding coal deposits in the concentration of REE were considered. Aluminosilicates, sulfides, and sulfates with inclusions of microparticles of rare and rare-earth REE elements were found in coals and clay interlayers.