STRUCTURE OF THE ORE HORIZON OF THE BURANNY SITE OF THE TOMTOR DEPOSIT AND DISTRIBUTION OF REE2O3 AND Y2O3

The paper discusses the structural-morphological characteristics of the ore horizon of the Buranny site of the Tomtor deposit (Arctic Siberia). At the base of the ore layer, the Northern and Southern depressions are established, separated by a linear elevation of sublatitudinal strike. In the Northern Depression, the pools of two submeridional structures are completely filled with ore material, and the pools of the third are partially filled. The pools of the sublatitudinal structure of the Southern Depression are partially filled with ore material. All pools are additionally filled with Permian coarse coal-bearing sediments. Differentiation of REE2O3 and Y2O3 within the ore layer is observed. The proportion (%) of Y2O3 from the sum of REE2O3+Y2O3 (YREE+Y) varies from 0.86 to 21%. Maximum values are observed at the saddles of the base of the ore layer, in local depressions of saddles or at the edges of pools. Ores with high YREE+Y values contain authigenic phosphates of both LREE and Y; the content of MREE and HREE increases in such ores. It is assumed that fluctuations in Eh-pH parameters during the accumulation of ore matter led to the fractionation of rare earth elements.