Tantal-niobium minerals of the upper riphean Fedotovskaya suite (the Middle Urals)

The petrographic peculiarities of the Fedotovskaya Suite of the Upper Riphean in the western slope of the Middle Urals are considered. The mineral varieties of tantal-niobium components (ilmenorutile, tantalorutile, yttrocolumbite, polycrase) and geochemical regularities in distribution of niobium concentrations in well sections are described. The connection of Nb high concentrations with metariolite and metabasalt layers is established. The rhythmical distribution of Nb along the carbon-serisite-quartz schist section with alternation of high and low concentrations is discovered. The results of study may be used for solution of theoretical problems of the black shales formation, as well as for designing the prospecting work on complex placers.