Bauxites of the Tatarka Deposit (Yenisei Ridge, Russia): The First Evidence of a Contact-Karst Origin

Abstract

Abstract The Tatarka bauxite deposit on the territory of the Russian Federation was formed as a result of sedimentation of the products of denudated lateritic weathering crusts of amphibolites in contact-karst depressions. Detailed mineralogical studies of bauxites made it possible to reconstruct reliably the conditions for their formation. As it turned out, the initial rocks and rocks, weathered before, have been denudated due to the close location of the areas of alimentation and accumulation. At the same time, chemical processes have been continued in karst depressions. For the first time, the presence of nanoparticles of amorphous aluminum oxide was revealed in contact-karst bauxites. This specific feature of the form of alumina precipitation is associated with the subsequent cessation of lateritization and their attenuation with depth. The presence of amorphous aluminum monohydrate must be taken into account when choosing a scheme for bauxite enrichment.