Doklady Earth Sciences

, Volume 483, Issue 2, pp 1504–1509 | Cite as

Carboniferous 40Ar/39Ar Age of Rare-Metal Enriched Rhyolites and Ignimbrites in the Sakmara Allochthon (Southern Urals)

  • A. V. RyazantsevEmail author
  • K. E. Degtyarev
  • A. V. Pilitsyna
  • I. A. Novikov


The Sakmara Allochthon (Southern Urals) comprises a widely distributed folded stratum of rhyolites and ignimbrites, which are characterized by Nb–Zr–REE geochemical specification. This stratum overlies unconformably folded Paleozoic complexes, including Devonian ones. Rhyolites contain potassium feldspar and quartz phenocrysts, as well as granite xenoliths. According to geochemical features, volcaniс rocks were formed under the intraplate setting; in terms of the chemical composition, they belong to the A-type granites. The 40Ar/39Ar age of the felsic rock groundmass of rhyolites is 303 ± 2 Ma. The feldspar phenocrysts yielded ages of 306 ± 3 and 337 ± 3 Ma. The first estimate, as well as the matrix age, is associated with the formation of the volcanic complex, while the second value is probably associated with the age of xenogenic material. The complex of rare-metal enriched rhyolites characterizes the stage of the terminal Late Carboniferous rift magmatism in the rear part of the active continental margin. This complex formed prior to collision and thrusting of ophiolitic allochthons.



We are grateful to E.V. Pushkarev, G.B. Fershtater, and E.M. Spiridonov for discussion of questions concerning the rock complex under consideration. This work was performed within the framework of the research project of Geological Institute, Russian Academy of Sciences, project no. 0135-2016-0009, and supported by the Russian Science Foundation, project no. 14-27-00058.


  1. 1.
    K. S. Ivanov, Dokl. Akad. Nauk SSSR 247 (4), 908–912 (1979).Google Scholar
  2. 2.
    V. F. Korobkov, B. K. Baimagambetov, P. K. Sapozhnikov, and K. E. Ulukpanov, Guide-Book of Excursions on Mugodzhary, Eastern Pre-Caspian, and Aktyubinsk Cis-Urals (Aktobe Sci. Res. Mining and Petroleum Inst., Aktobe, 2012) [in Russian].Google Scholar
  3. 3.
    S. A. Malyutin, I. F. Gradovskii, and E. A. Uspenskaya, Izv. Vyssh. Uchebn. Zaved., Geol. Razved., No. 5, 22–31 (2007).Google Scholar
  4. 4.
    E. V. Pushkarev, P. A. Serov, and A. P. Biryuzova, Dokl. Earth Sci. 413 (2), 198–202 (2007).CrossRefGoogle Scholar
  5. 5.
    E. V. Pushkarev and G. B. Fershtater, in Annual-1985 (Zavaritsky Inst. Geol. Geochem., Ural Sci. Center USSR Acad. Sci., Sverdlovsk, 1986), pp. 44–45 [in Russian].Google Scholar
  6. 6.
    A. V. Ryazantsev and T. Yu. Tolmacheva, Geotectonics 50 (6), 553–578 (2016).CrossRefGoogle Scholar
  7. 7.
    D. N. Salikhov, V. M. Moseichuk, V. N. Puchkov, et al., Litosfera, No. 5, 165–171 (2013).Google Scholar
  8. 8.
    D. N. Salikhov, V. V. Kholodnov, T. A. Osipova, and I. R. Rakhimov, Litosfera, No. 5, 35–57 (2016).Google Scholar
  9. 9.
    V. N. Smirnov, G. B. Fershtater, and K. S. Ivanov, Litosfera, No. 2, 40–56 (2003).Google Scholar
  10. 10.
    Al. V. Tevelev, I. A. Kosheleva, M. A. Furina, and B. V. Belyatskii, Moscow Univ. Geol. Bull. 64 (2), 92–110 (2009).Google Scholar
  11. 11.
    G. B. Fershtater, Paleozoic Intrusive Magmatism of the Middle and Southern Urals (Ural Branch Russ. Acad. Sci., Yekaterinburg, 2013) [in Russian].Google Scholar
  12. 12.
    M. A. Furina, Extended Abstract of Candidate’s Dissertation in Geology and Mineralogy (Moscow, 2010).Google Scholar
  13. 13.
    J. A. Pearce, N. B. Harris, and A. G. Tindle, J. Petrol. 25, 956–983 (1984).CrossRefGoogle Scholar
  14. 14.
    J. G. Price, R. N. Jeffrey, C. D. Henry, et al., Geol. Soc. Am., Spec. Pap. 246, 103–120 (1990).Google Scholar
  15. 15.
    S. S. Sun and W. F. McDonough, Geol. Soc. London, Spec. Publ. 42, 313–345 (1989).CrossRefGoogle Scholar

Copyright information

© Pleiades Publishing, Ltd. 2018

Authors and Affiliations

  • A. V. Ryazantsev
    • 1
    Email author
  • K. E. Degtyarev
    • 1
  • A. V. Pilitsyna
    • 1
  • I. A. Novikov
    • 2
  1. 1.Geological Institute, Russian Academy of SciencesMoscowRussia
  2. 2.Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of SciencesMoscowRussia

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