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The Turupya deposit is located in the Northern Urals (heads of river Bol. Turupya, Mal. Tuyakhlanya). Structurally the area is located in the transition zone between the Central Ural uplift and Tagil-Magnitogorsk depression and corresponds to the front part of Main Ural Thrust.
The mineralization is confined to micaceous-quartz-albite or micaceous-carbonate-quartz shales, metasomatic and localized in the fault zone in low grade metamorphites. Genetically the mineralization was connected with the formation of alkaline metasomatites, however it was noted the rocks had a complex of transitional features making them similar to carbonatites. First researchers genetically connected this mineralization with the newly discovered dikes of alkaline syenites on this territory.
It is determined that the mineralized rocks are connected with alkaline metasomatites on sedimentary and volcanogenic substrata. Primary sedimentary rocks are defined by preserved psammitic and psamittic-aleurite structures and rounded mineral debris with regeneration edges. The direct evidence of volcanogenic nature of the substratum is the presence of areas with relict microfelsite or aplite structures. Also primary sedimentary carbonates of calcite-dolomitic composition are present. Quarz-feldspar-carbonate rocks are determined, where the carbonate part is represented by ankerite together with calcite and dolomite. Such zones are considered as zones of maximally expressed metasomatites.
Chemical studies testify to Na2O enriching of all the rocks in the zone (to 10 wt. %), albitization and paragonitization are developed accordingly. In the case of development of such processes in rocks their chemical composition is approximating to typical compositions of alkaline rocks.
At maximal mineralization places the content (ppm) is: Nb - 800, Ta - 260, Hf - 250, Zr - 3000, REE - 1000 (light dominate heavy), Y - 200, U - 30 , Th - 220, Zn - 800 , Pb - 140, Be - 90.
The ores under study are represented by niobium and tantalum minerals: generally columbite - Fe-columbite, Mn-columbite (pyrochlorine - by precursors), rare earths (bastnaesite, monazite), zircon.
Microprobe investigations have determined that fine disperse ore complex is confined to thin phengite veins in micaceous-carbonate-quartz-albite shales. The phengite veins are sated with thin thread-like colloform inclusions of zircon and isometric grains of columbite. Besides, areas rich in bastnaesite and monazite are confined to them. There is constant presence of high fluorine apatite in rocks with F content - 4-7 wt. %. F content in rocks can reach 4000 ppm (by spectral quantitative analysis).
Thus, the ores are connected with a general alkaline (sodium) rock alteration and also carbonatization and silicification (fluoritization is limited). They are characterized by bastnaesite-columbite-zircon content, and also by the presence of apatite and monazite. The form of zircon and columbite is very specific.
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