Crichtonite groupminerals in massive sulfide ores and ore metasomatites of Proterozoic structures of the Kola region
Karpov S. M., Voljshin A. V., Kompanchenko A. A., Savchenko Ye. E., Bazay A. V.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2016. V. 145. N 5. P. 39-56
A wide variety and geographic range of the crichtonite group minerals have been defined in massive sulfide ores and ore metasomatites of the Proterozoic rifting structures at Kola Peninsula, i.e. the Pechenga-Imandra-Varzuga and Salla-Kuolayarvi structures. The minerals are adjacent to the pyrrhotite occurrences and related metasomatites, occupying a certain position in the section of mineral bodies. These crichtonite group minerals are represented by six species: crichtoniite, davidite-(Ce), davidite-(La), loveringite, senaite, lindsleyite. The two latter have been defined in the Kola region for the first time. A phase close to mathiasite by the species-forming cations has been also defined. The crichtonite group minerals are tightly inter-growing, and this reflects in compositions of individual minerals in such aggregates. Transition phases are common. Compositions of the studied minerals perform a high grade of vanadium (up to 20 %V2O3) and scandium (up to 2.4 %Sc2O3). Their compositions testify to the vanadium and scandium geochemical specialization of the host supracrustal formations. It is also confirmed by a number of vanadium minerals having been defined in pyrrhotite occurrences of the South Pechenga and Western Imandra-Varzuga structural zone.
Key words: crichtonite group, crichtonite, davidite-(Ce), davidite-(La), loveringite, senaite, lindsleyite, vanadium, scandium, massive sulfide ore deposits, ore metasomatites, Kola region.