Prospects for the titanium carrying Triassic formations of the Bolshaya Synya depression of the Pre-Uralian marginal flexure

Abstract

It was established potentially industrial titanium-containing terrigenous rocks from the Lower and Middle Triassic formations of the southern part of the Bolshaya Synya depression, Pre-Uralian marginal flexure. Sandstones contain the bulk of productive mineralization and makeup about 80% of the Triassic section. Sandstones are represented by weakly lithified, finely grained lithoclast greywackes scattered in the hands with weakly rounded unsorted fragments, with pore, film, and contact type of cement form by hydrogetite and illite and chlorite. The proportion of relatively strong sandstones with calcite-siderite cement does not exceed 10% of the studied section. The deposits are formed in alluvial and pluvial, lacustrine depositional environments within the wide alluvial plain. The rocks belong to the upper part of the thick Permo-Triassic continental molasses formed in compensated depressions as a result of the destruction of the Paleo Uralian Orogeny. The main minerals of the heavy fraction are epidote, ilmenite, titanomagnetite, and amphibole; the minor minerals are chlorite, goethite, martite, pyroxene, chrome spinel and a group of garnets. The share of zircon does not exceed the first percent. The main mineral concentrator of titanium is ilmenite, the minor minerals are manganilmenite, titanomagnetite, titanite, leucoxene aggregates, rutile, and pyrophanite. The hypothetical primary source of ilmenite was epidote and amphibole contains shale or epidote containing amphibolite formed from a mafic substrate. The thickness of titanium contains layers is 1–4 m with an ilmenite content of more than 30 kg/m3. At the local level, ilmenite and titanomagnetite mineralization is concentrated in the form of small jets, lenses, puffs, and interlayer bodies. The average contents of ilmenite are comparable with those of the well-known titanium and zirconium placer deposits in Russia. The data presented in the article make it possible to predict the existence of new titanium contains region in the Triassic deposits of the south part of the Bolshaya Synya depression. The productivity of the region should be associated with continental ilmenite placers.