The paper presents new data on the Th-REE mineralization, common in clastic rocks of Bashkirian meganticlinorium. The detailed description of the new pas parageneses and associations found in rocks Suran Formation (RF1) and Mashak Formation (RF2). On the basis of the study of the chemical composition of minerals, four mechanisms for the formation of thorium-rare-earth mineralization are proposed: \"hydrothermal\", \"exocontact\", \"fluid-magmatic\" and \"alluvial-metamorphogenic\". It is shown that the seeming of the mechanisms is realized at a certain stage of geodynamic development of the region.
Key words: Bashkir meganticlinorium, thorium-rare-earth mineralization, Suran Formation, Mashak Formation, rare-earth elements.