Distribution of REE, Y, Sc, and Th in the unique complex rare-metal ores of the Tomtor deposit

Abstract

The REE (Ln), Y, Sc, and Th distribution in the unique complex rare-metal ores of the Tomtor deposit is considered. Significant variability of these components and REE composition is revealed. Ore blocks with elevated Y and HREE contents are identified among prevailing LREE-enriched ores. It is established that the REE variations in the ores are correlated with evolution of REE carriers during epigenetic transformations of the carbonatite weathering products, in particular, with a replacement of Ce-bearing minerals (monazite and florencite) by Y-bearing mineral, xenotime. It is found that LREE and HREE exhibit different behavior during formation of the Tomtor ores, which is expressed in the inert behavior and residual accumulation of Ce-group REE at essential introduction of Y, HREE, Sc, and Th during epigenetic transformation of weathering products of carbonatites, which represent one of the main factors of the formation of the unique rare-metal ores of the Tomtor deposit.