minerals Article Vanadium Mineralization in the Kola Region, Fennoscandian Shield Alena A. Kompanchenko * , Anatoly V. Voloshin and Victor V. Balagansky Geological Institute of the Federal Research Centre Kola Science Centre of the Russian Academy of Sciences, 14 Fersman Street, Apatity 184209, Russia; [email protected] (A.V.V.); [email protected] (V.V.B.) * Correspondence: [email protected]; Tel.: +7-921-0488782 Received: 24 September 2018; Accepted: 18 October 2018; Published: 23 October 2018 Abstract: In the northern Fennoscandian Shield, vanadium mineralization occurs in the Paleoproterozoic Pechenga–Imandra-Varzuga (PIV) riftogenic structure. It is localized in sulfide ores hosted by sheared basic and ultrabasic metavolcanics in the Pyrrhotite Ravine and Bragino areas and was formed at the latest stages of the Lapland–Kola orogeny 1.90–1.86 Ga ago. An additional formation of vanadium minerals was derived from contact metamorphism and metasomatism produced by the Devonian Khibiny alkaline massif in the Pyrrhotite Ravine area. Vanadium forms its own rare minerals (karelianite, coulsonite, kyzylkumite, goldmanite, mukhinite, etc.), as well as occurring as an isomorphic admixture in rutile, ilmenite, crichtonite group, micas, chlorites, and other minerals. Vanadium is inferred to have originated from two sources: (1) basic and ultrabasic volcanics initially enriched in vanadium; and (2) metasomatizing fluids that circulated along shear zones. The crystallization of vanadium and vanadium-bearing minerals was accompanied by chromium and scandium mineralization. Vanadium mineralization in Paleoproterozoic formations throughout the world is briefly considered. The simultaneous development of vanadium, chromium and scandium mineralizations is a unique feature of the Kola sulfide ores. In other regions, sulfide ores contain only two of these three mineralizations produced by one ore-forming process. Keywords: vanadium mineralization; mineralogy; Paleoproterozoic; Kola region; Arctic zone; Fennoscandian Shield 1. Introduction Vanadium is a fairly widespread element. It is present in all major types of rocks of the Earth’s crust, in meteorites, spectra of stars and the Sun. The vanadium content in the Earth’s crust is estimated at 1.6 × 10−2 mass % and in oceans 3.0 × 10−7 mass % [1]. Vanadium in the Earth’s crust can create compounds or be present in them in the form of V3+,V4+ and V5+. Vanadium and vanadium-bearing minerals are formed in different genetic settings. In minerals of magmatic rocks vanadium is found mainly in the trivalent form as an isomorphic admixture. Typical Fe-Ti-V ores are related to mafic-ultramafic rocks (for example, the Kolvitsa massif in the Kola region [2], the Bushveld layered intrusion in South Africa [3,4], and the Pan-Xi intrusion in China [5,6]). In these ores, vanadium is present predominantly in oxide minerals as an isomorphic admixture. In the Buena Vista Hills Fe-V deposit in Nevada (USA), submicroscopic exsolution lamellae of coulsonite FeV2O4 were revealed in magnetite [7]. Rare vanadium minerals were discovered in rocks initially enriched with vanadium and metamorphosed up to amphibolite facies. For example, tanzanite, a blue vanadium-bearing variety of zoisite, is an extremely rare mineral and occurs in the only deposit of tanzanite in the world in Tanzania [8]. Natalyite NaVSi2O6 [9], magnesiocoulsonite MgV2O4 [10], Minerals 2018, 8, 474; doi:10.3390/min8110474 www.mdpi.com/journal/minerals Minerals 2018, 8, 474 2 of 20 Minerals 2018, 8, x FOR PEER REVIEW 2 of 20 3+ 4+ oxyvanite[9], magnesiocoulsonite V 2V O5 [11 ]MgV were2O found4 [10], amongoxyvanite other V3+ vanadium2V4+O5 [11] minerals were found in the among Sludyanka other complex vanadium in theminerals southern in the Baikal Sludyanka area (Russia). complex in the southern Baikal area (Russia). AA widewide varietyvariety ofof vanadiumvanadium mineralsminerals hashas beenbeen establishedestablished inin metamorphosedmetamorphosed massivemassive sulfidesulfide ores,ores, describeddescribed soso farfar onlyonly inin supracrustalsupracrustal unitsunits ofof severalseveral PaleoproterozoicPaleoproterozoic riftogenicriftogenic structuresstructures ofof thethe ancientancient shieldsshields ofof thethe world.world. VanadiumVanadium mineralizationmineralization inin sulfidesulfide oresores waswas reportedreported inin thethe KolaKola regionregion inin RussiaRussia [ 12[12–14],–14], the the Outokumpu Outokumpu and and Vihanti Vihant depositsi deposits in in Finland Finland [15 [1,165,16],], the the Sätra Sätra deposit deposit in Swedenin Sweden [17 ],[17], and and the the Rampura Rampura Agucha Agucha deposit deposit in India in India [18]. [18]. The The Outokumpu Outokumpu and and Sätra Sätra deposits deposits are theare typethe type of localities of localities for karelianite for karelianite V2O3 andV2O3 vuorelainenite and vuorelainenite MnV2 OMnV4, respectively2O4, respectively [15,17 ].[15,17]. All these All massivethese massive sulfide oresulfide deposits ore anddeposits occurrences and wereoccurre formednces c.were 1.9 Gaformed ago and c. were1.9 metamorphosedGa ago and were up tometamorphosed amphibolite or evenup to granulite amphibolite facies. or This even work gran givesulite a comprehensivefacies. This work description gives a ofcomprehensive the vanadium mineralizationdescription of inthe the vanadium Paleoproterozoic mineralization Pechenga–Imandra-Varzuga in the Paleoproterozoic (PIV) Pechenga–Imandra-Varzuga riftogenic structure in the northern(PIV) riftogenic Fennoscandian structure Shield. in the Itnorthern bases on Fennoscandi the authors’an data Shield. on the It Pyrrhotitebases on the Ravine authors' deposit data and on thethe BraginoPyrrhotite occurrence Ravine deposit of sulfide and ores the and Bragino literature occurren data once aof vanadium sulfide ores mineralization and literature in xenoliths data onof a Paleoproterozoicvanadium mineraliza supracrustaltion in rocksxenoliths in the of Devonian Paleoproterozoic Khibiny alkaline supracrustal massif. rocks This work in the also Devonian contains aKhibiny brief comparative alkaline massif. analysis This of vanadium work also mineralization contains a inbrief the Paleoproterozoiccomparative analysis supracrustal of vanadium units of themineralization ancient shields in the of thePaleoproterozoic world. supracrustal units of the ancient shields of the world. 2.2. GeologicalGeological SettingSetting TheThe Polmak–Pasvik–Pechenga–Imandra-VarzugaPolmak–Pasvik–Pechenga–Imandra-Varzuga riftogenic belt (further,(further, Pechenga–Varzuga)Pechenga–Varzuga) isis locatedlocated inin aa transitionaltransitional zonezone betweenbetween thethe orogenicorogenic corecore andand north-easternnorth-eastern forelandforeland ofof thethe PaleoproterozoicPaleoproterozoic Lapland–KolaLapland–Kola collisional collisional orogen orogen [19, 20[19,20]] (Figure (Figure1). This 1). belt This is a detailedbelt is geologicala detailed recordgeological of the record Paleoproterozoic of the Paleoproterozoic in the Fennoscandian in the Fennoscandian shield [21– shield25]. It includes[21–25]. It an includes almost an complete almost Paleoproterozoiccomplete Paleoproterozoic stratigraphy stratigraphy and all major and typesall ma ofjor Paleoproterozoic types of Paleoproterozoic plutonicrocks plutonic in northern rocks in Fennoscandia.northern Fennoscandia. Its largest Its and largest well studiedand well Pechenga studied andPechenga Imandra-Varzuga and Imandra-Varzuga structures arestructures located are in thelocated Kola in region the Kola (Figure region1) and (Figure are described 1) and are in described detail in [in22 detail]. in [22]. Figure 1.1. Tectonic mapmap ofof thethe northernnorthern FennoscandianFennoscandian ShieldShield (modified(modified fromfrom[ [19,20]).19,20]). 2.1.2.1. Imandra-VarzugaImandra-Varzuga StructureStructure ThisThis structurestructure consistsconsists ofof widewide northeasternnortheastern andand narrownarrow southwesternsouthwestern structuralstructural zoneszones [[22,26]22,26] (Figure(Figure1 ).1). TheThe formerformer extendsextends alongalong thethe entireentire Imandra-Varzuga Imandra-Varzuga structure, structure, whereas whereas the the latter latter is is exposed only in its central and western parts. The north-eastern zone is appoximately a SW-dipping monocline. In the south-western zone rocks dip steeply to the south-west and north-east and are Minerals 2018, 8, 474 3 of 20 Minerals 2018, 8, x FOR PEER REVIEW 3 of 20 exposed only in its central and western parts. The north-eastern zone is appoximately a SW-dipping monocline. In the south-western zone rocks dip steeply to the south-west and north-east and are locally locally intensely tectonized and folded. Rocks are thrust over Archean basement gneisses in the intensely tectonized and folded. Rocks are thrust over Archean basement gneisses in the western western portion of the structure and are tectonically overlain by these gneisses in its central portion. portion of the structure and are tectonically overlain by these gneisses in its central portion. Both the Both the zones were metamorphosed under conditions of greenschist to amphibolite facies [27]. zones were metamorphosed under conditions of greenschist to amphibolite facies [27]. The Imandra-Varzuga stratigraphy consists of three groups (from bottom to top): Strelna, The Imandra-Varzuga stratigraphy consists of three groups (from bottom to top): Strelna, Varzuga, Varzuga, and Tominga [22,26]. The Strelna and Varzuga groups are dominated