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)

The Ilmeno-Vishnevogorsky miaskite-phenite-carbonatite complex (IVС), located in the Urals folded region, is a representative of "linear type" carbonatite complexes, with which Nb-Zr deposits are associated. The ore potential of linear carbonatite complexes, the time and duration of ore-forming processes, and the geodynamic setting remain the subject of discussion. In order to estimate the age and duration of ore formation processes in the IVC, the U-Pb dating of zircon (LA-ICP-MS) from miaskite-pegmatites, as well as Rb-Sr dating of ore-bearing (pyrochlore-bearing) varieties of miaskite-pegmatites and carbonatites (ID-TIMS) were carried out. The U-Pb dating of zircon from the IVC miaskite-pegmatites showed the Permian age (280±8 Ma, P₁ – age of the main zircon generation). The Rb-Sr-mineral isochron of miaskite-pegmatite showed a close age of 274±5 Ma (P₁), confirming the results of U-Pb-dating of miaskite-pegmatites. The Rb-Sr dating of pyrochlore carbonatite varieties (sovites II) showed an age of 250±3 Ma (T₁). The results of Rb-Sr- and U-Pb dating indicate that the processes of pegmatite- and carbonatite formation and the associated Zr-Nb ore formation in IVC occurred at the late collisional and postcollisional stage of development of the Ural folded region. Based on the data obtained, the geodynamic model for the IVC formation was proposed.

1. Abramov S.S., Rass I.T., Kononkova N.N., 2020. Fenites of the Miaskite–Carbonatite Complex in the Vishnevye Mountains, Southern Urals, Russia: Origin of the Metasomatic Zoning and Thermodynamic Simulations of the Processes. Petrology 28, 263–286. https://doi.org/10.1134/S0869591120030029.

2. Attoh K., Corfu F., Nude P.M., 2007. U-Pb Zircon Age of Deformed Carbonatite and Alkaline Rocks in the Pan-African Dahomeyide Suture Zone, West Africa. Precambrian Research 155 (3–4), 251–260. http://doi.org/10.1016/j.precamres.2007.02.003.

3. Belyatsky B.V., Lepekhina E.N., Antonov A.V., Rodionov N.V., Petrov O.V., Shevchenko S.S., Sergeev S.A., Nedosekova I.L., 2018. The Age of Nb Rare-Metal Mineralization of the Ilmeny–Vishnevogorsky Alkaline Complex (South Urals). Doklady Earth Sciences 481, 1079–1085. http://doi.org/10.1134/S1028334X18080251.

4. Burke K., Ashwal L.D., Webb S.J., 2003. New Way to Map Old Sutures Using Deformed Alkaline Rocks and Carbonatites. Geology 31 (5), 391–394. http://doi.org/10.1130/0091-7613(2003)031<0391:NWTMOS>2.0.CO;2.

5. Burke K., Khan S., 2006. Geoinformatic Approach to Global Nepheline Syenite and Carbonatite Distribution: Testing a Wilson Cycle Model. Geosphere 2 (1), 53–60. http://doi.org/10.1130/GES00027.1.

6. Chernyshev I.V., Kononova V.A., Kramm U., Grauert B., 1987. Isotope Geochronology of the Alkaline Rocks in the Urals Acquired by U-Pb Method from Zircons. Geochemistry 3, 323–338 (in Russian)

7. Ivanov K.S., 2011. The Nature of the Ural Carbonatites. Lithosphere 1, 20–33 (in Russian)

8. Kononova V.A., Dontsova E.I., Kuznetsova L.D., 1979. Isotope Composition of Oxygen and Strontium of the Ilmen-Vishnevogorsky Alkaline Complex and Genesis of Miaskites. Geochemistry 12, 1784–1795 (in Russian)

9. Kramm U., Blaxland A.B., Kononova V.A., Grauert B., 1983. Origin of the Ilmenogorsk-Vishnevogorsk Nepheline Syenites, Urals, USSR, and Their Time of Emplasement during the History of the Ural Fold Belt: A Rb-Sr Study. The Journal of Geology 91 (4), 427–435. https://doi.org/10.1086/628788.

10. Kramm U., Chernyshev I.V., Grauert B., Kononova V.A., Broker V., 1993. The U-Pb Systematics of Zircons: Study of Zircons in Nepheline Syenites of the Ilmen Mountains, the Urals. Petrology 1 (5), 536–549 (in Russian)

11. Krasnobaev A.A., Rusin A.I., Busharina S.V., Lepekhina E.N., Medvedeva E.V., 2010а. Character of Zircon Distribution on Amphibole Miaskite of the Ilmenogorsk Massif (Southern Urals). Doklady Earth Sciences 430, 76–79. https://doi.org/10.1134/S1028334X10010174.

12. Krasnobaev A.A., Rusin A.I., Valizer P.M., Busharina S.V., 2010b. Zirconology of Calcite Carbonatite of the Vishnevogorsk Massif, Southern Urals. Doklady Earth Sciences 431, 390–393. https://doi.org/10.1134/S1028334X10030268.

13. Krasnobaev A.A., Valizer P.M., Anfilogov V.N., Nemov A.B., Busharina S.V., 2014. Zirconology of Pegmatites of the Ilmeny Mountains. Doklady Earth Sciences 457, 960–964. https://doi.org/10.1134/S1028334X14080066.

14. Krasnobaev A.A., Valizer P.M., Busharina S.V., Medvedeva E.V., 2016. Zirconology of Miaskites of the Ilmeny Mountains, South Ural. Geochemistry International 54, 765–780. https://doi.org/10.1134/S0016702916070041.

15. Levin V.Ya., Ronenson B.M., Samkov V.S., Levina I.A., Sergeev N.S., Kiselev A.P., 1997. Alkaline-Carbonatite Complexes of the Urals. Uralgeolkom Publishing House, Ekaterinburg, 270 p. (in Russian)

16. Mitchell R.H., 2005. Carbonatites and Carbonatites and Carbonatites. The Canadian Mineralogist 43 (6), 2049–2068. http://doi.org/10.2113/gscanmin.43.6.2049.

17. Nedosekova I.L., Belousova E.A., Belyatskiy B.V., 2014. The U-Pb Age and Lu-Hf Isotope Systems of Zircons from the Ilmen-Vishnevogorskiy Alkaline-Carbonatite Complex, the Southern Urals. Lithosphere 5, 19–32 (in Russian)

18. Nedosekova I.L., Belousova E.A., Sharygin V.V., Belyatsky B.V., Baynova T.B., 2013. Origin and Evolution of the Il’meny-Vishnevogorsky Carbonatites (Urals, Russia): Insights from Trace-Elements Compositions, Rb-Sr, Sm-Nd, U-Pb and Lu-Hf Isotope Data. Mineralogy and Petrology 107, 101–123. https://doi.org/10.1007/s00710-012-0223-9.

19. Nedosekova I.L., Belyatsky B.V., 2012. Age and Substance Sources of the Ilmeno–Vishnevogorsky Alkaline Complex (South Urals): Rb-Sr, Sm-Nd, U-Pb, and Lu-Hf Isotope Data. Doklady Earth Sciences 446, 1071–1076. https://doi.org/10.1134/S1028334X12090061.

20. Nedosekova I.L., Belyatsky B.V., Belousova E.A., 2016. Trace Elements and Hf Isotope Composition as Indicators of Zircon Genesis in the Evolution of the Alkaline-Carbonatite Magmatic System (Ilmeno-Vishnevogorsky Complex, Urals, Russia). Russian Geology and Geophysics 57 (6), 891–906. https://doi.org/10.1016/j.rgg.2015.09.021.

21. Nedosekova I.L., Koroteev V.A., Bayanova T.B., Serov P.A., Popova V.I., Chervyakovskaya M.V., 2020. On the Age of Pyrochlore Carbonatites from the Ilmeno-Vishnevogorsky Alkaline Complex, the Southern Urals (Insights from Rb-Sr and Sm-Nd Isotopic Data). Lithosphere 20 (4), 486–498 (in Russian) https://doi.org/10.24930/1681-9004-2020-20-4-486-498.

22. Nedosekova I.L., Vladykin N.V., Pribavkin S.V., Bayanova T.B., 2009. The Il’mensky-Vishnevogorsky Miaskite-Carbonatite Complex, the Urals, Russia: Origin, Ore Resource Potential, and Sources. Geology of Ore Deposits 51, 139. https://doi.org/10.1134/S1075701509020056.

23. Puchkov V.N., 2010. Geology of the Urals and Cis-Urals (Topical Issues of Stratigraphy, Tectonics, Geodynamics and Metallogeny). DizaynPoligrafServis, Ufa, 280 p. (in Russian)

24. Rass I.T., Abramov S.S., Utenkov V.A., Kozlovskii V.M., Korpechkov D.I., 2006. Role of Fluid in the Genesis of Carbonatites and Alkaline Rocks: Geochemical Evidence. Geochemistry International 44, 636–655. https://doi.org/10.1134/S0016702906070020.

25. Ronenson B.M., 1966. Origin of Miaskites and Relationship to Rare-Metal Mineralization. Geology of Rare-Element Deposits. Nedra, Moscow, 176 p. (in Russian)

26. Rusin A.I., Krasnobaev A.A., Valizer P.M., 2006. Geology of the Ilmen Mountains. In: Е.P. Makagonov (Ed.), Geology and Mineralogy of the Ilmenogorsky Complex: Situation and Problems. ISR UB RAS, Miass, p. 3–20 (in Russian)

27. Valentin E., Botelho N.F., Dantas E.L., 2020. Monte Santo Suite, an Example of Ediacaran-Cambrian Deformed Alkaline Rocks in the Araguaia Belt, Central Brazil. Implications for Western Gondwana Evolution. Lithos 366, 105552. http://doi.org/10.1016/j.lithos.2020.105552.

28. Zaitceva M.V., Pupyshev A.A., Shchapova J.V., Votyakov S.L., 2016. Dating of Zircons Using NexION 300S Quadrupole Mass Spectrometer with Inductively Coupled Plasma and NWR 213 Attachment for Laser Ablation. Analytics and Control 20 (4), 294–306 (in Russian) http://doi.org/10.15826/analitika.2016.20.4.006.

29. Zoloev K.R., Levin V.Ya., Mormil S.I., Shardakova G.Yu., 2004. Mineral Genesis and Deposits of Rare Metals, Molybdenum and Tungsten of the Urals. Ural Geological Survey Expedition, Ekaterinburg, 336 p. (in Russian)