Ages of formation weathering crusts and connection with deposits of lateral kaolins and ceramic clays within phanerozoic of the Voronezh anticlise

Abstract

Within phanerozoic of the Voronezh anteclise stand out: predevonian, late eiffelian-early give-tian, early frasnian, early carboniferous, early mesozoic (late triassic-early jurassic), early cretaceous (aptian), late cretaceous-early paleogene, late oligocene-early miocene weathering crust. The most powerful and productive were formed in paleozoic by rocks of crystalline basement. In pre- and devonian times kaolin weathering crust was formed along granitoids, gneisses, and shales of crystalline basement. Due to its erosion in erosion-tectonic depression in the south of the anteclise accumulated powerful mamon sandy-kaolin stratum promising for the discovery of large deposits of lateral kaolin, sands-kaolin mixtures and quartz sands. Deposits of rich iron ores on BIFs and bauxites on shales are associated with early carboniferous time. On granites and gneisses developed in low relief forms, kaolin weathering crust was formed, but it and visean clays correlated to it have no industrial value due to the large depths. In aptian time not only variegated weathering crust was formed from neocomian deposits, but also widely developed kaolin clay correlated to it in quartz sand. Within weathering crust of sedimentary rocks formed ceramic clay of low quality in marine basins. In Neogene time in continental conditions within the alluvial plains, deposits of refractory clays of better quality than paleogene, but replaced by aptian clay on this basis. Thus, in the history of the region as a positive structure, the formation of weathering crust and correlate deposits occurred repeatedly, but favorable paleogeographic and tectonic conditions were necessary for the formation of deposits lateral kaolin and ceramic clays. At the same time, the facies of clay formation at each stratigraphic level significantly differed, which affected the material composition, technological properties of raw materials and the scale of existing and prospects for discovering new deposits.