The Il’mensky-Vishnevogorsky miaskite-carbonatite complex, the Urals, Russia: Origin, ore resource potential, and sources

Abstract

followed in the mid-20th century by E.M. Bonstedt-Kupletskaya, E.S. Il'menev, I.G. Isakov, A.G. Zhabin, E.M. Es'kova, N.V. Svyazhin, B.M. Ronenson, V.Ya. Levin, A.G. Bazhenov, V.O. Polyakov, V.A. Popov, V.A. Popova, V.A. Kononova, I.V. Chernyshev, V.S. Samoilov, A.S. Talantsev, and others.In the 1940s, a geological exploration expedition headed by Isakov discovered endogenetic carbonate veins with pyrochlore mineralization and Zone 140 of the Vishnevogorsky niobium deposit, related to pyrochlore-bearing carbonatite. The mining operations at Abstract -The origin and sources of the Il'mensky-Vishnevogorsky miaskite-carbonatite complex, one of the world's largest alkaline complexes, with unique rare-metal and colored-stone mineralization and Nb, Zr, and REE deposits, are discussed in this paper. Geochemical and isotopic studies, including of Nd, Sr, C, and O isotopes, as well as estimation of PT formation conditions, of miaskites and carbonatites from various deposits of the Il'mensky-Vishnevogorsky Complex have been carried out. The Vishnevogorsky, Potaninsky, and Buldym Nb-REE deposits and the Il'mensky, Baidashevo, and Uvil'dy occurrences related to carbonatites were investigated. Their geological setting, composition, and ore resource potential are characterized. The genetic models and typical features of the Il'mensky-Vishnevogorsky Complex are considered. The rocks of the Il'menskyVishnevogorsky Complex were formed at T = 1000-230 ° C and P = 2-5 kbar. Carbonated miaskite melt was divided into immiscible silicate and carbonate liquids at T = 1000 ° C and P = 5 kbar. Miaskite crystallized at T = 850-700 ° C and P = 3.5-2.5 kbar. The formation temperature of carbonatite I of the Vishnevogorsky pluton was close to the temperature of miaskite crystallization (700-900 ° C). The crystallization temperature of carbonate-silicate rock and carbonatite I in the Central alkaline tract was 650-600 ° C. The formation temperature of carbonatite II varied from 590 to 490 ° C. Dolomite-calcite carbonatite III and dolomite carbonatite IV of the Buldym massif were formed at T = 575-410 ° C and T = 315-230 ° C, respectively. The geochemical features of carbonatites belonging to the Il'mensky-Vishnevogorsky Complex differ from those of carbonatites related to alkaline ultramafic rocks and are close to those of carbonatites related to nepheline syenite or carbonatites localized in linear fracture zones. A high Sr content in early carbonatites along with relatively low Ba, Nb, Ta, Ti, Zr, and Hf contents and a certain enrichment in HREE (a low La/Yb ratio) in comparison with carbonatites of the alkaline ultramafic association are typical. The geochemistry of carbonatites of the Il'mensky-Vishnevogorsky Complex corresponds to the trend of geochemical evolution of carbonatitic melts and their fluid derivatives. The Sr, Nd, C, and O isotopic compositions indicate a mantle magmatic source of the Il'mensky-Vishnevogorsky Complex and participation of moderately depleted mantle (DM) and enriched mantle EM1 in magma generation. Carbonatite...

Origin of Blue Sapphire in Newly Discovered Spinel–Chlorite–Muscovite Rocks within Meta-Ultramafites of Ilmen Mountains, South Urals of Russia: Evidence from Mineralogy, Geochemistry, Rb-Sr and Sm-Nd Isotopic Data

“…Black arrows show the source of major elements of metasomatites. Chemistry of miascite is after[25] Variations of selected elements in whole-rock compositions from Table S13. Black arrows show the source of major elements of metasomatites.…”

“…Black arrows show the source of major elements of metasomatites. Chemistry of miascite is after[25].…”

“…Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu K Nb Ta La Ce Sr Pr Nd Zr Sm Eu Ti Gd Dy Er Yb Lu Sample/Primitive mantle meta-ultramafite (418-3)meta-ultramafite (418-4(a) Chondrite-normalized REE diagram of selected samples, the chondrite REE data are after[26]; (b) Trace elements diagram of selected samples normalized to primitive mantle, data on trace elements in primitive mantle are after[26]. Chemistry of miascite is after[25].…”

AGE AND GEODYNAMIC SETTINGS OF MIASKITE-PEGMATITES, CARBONATITES, AND Nb-Zr MINERALIZATION OF THE ILMENO-VISHNEVOGORSKY ALKALINE COMPLEX, SOUTH URAL (U-Pb AND Rb-Sr ISOTOPE DATA)

“…ИВК состоит из двух крупных факолитоподобных массивов нефелиновых сиенитов (миаскитов) с карбонатитами, залегающих в сводовых частях антиклинали, и протяженной (~100 км) линейной зоны -Центральной щелочной полосы, сложенной фенитами, пластообразными телами миаскитов, сиенитов, глиммеритоподобных пород и карбонатитов [Levin et al, 1997;Nedosekova et al, 2009], которая залегает субсогласно уральским коллизионным тектоническим структурам субмеридионального простирания (Прил. 1, рис.…”

“…Карбонатиты часто брекчированны, содержат округлые фрагменты вмещающих миаскитов или фенитов и крупные зерна их минералов, сцементированные мелкозернистой альбит-биотиткальцитовой основной массой. Более поздние жилы карбонатитов (сёвиты II) -лейкократовые, крупнозернистые, с полосчатым распределением силикатных и акцессорных минералов, содержат крупные (до 20 см) кристаллы биотита, апатита, альбита, красного пирохлора, ильменита, циркона, магнетита, пирротина, пирита [Nedosekova et al, 2009].…”