Geochronological scale and evolution of late Cenozoic magmatism within the Caucasian segment of the alpine belt

V. A. Lebedev1, I. V. Chernyshev1, E. V. Sharkov1
1Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Moscow, Russia

Tóm tắt

Results of the isotope-geochronological studies of the Late Cenozoic magmatism of Caucasus have been considered. The Neogene-Quaternary volcanic activity is found to have evolved during the last 15 m. y. being most intensive in the Middle-Late Pliocene. Within separate neovolcanic areas of the Caucasus region, magmatism was of a clearly discrete character when intense eruption periods interchanged with prolonged (up to several million years) times of quiet conditions. Four stages of young magmatism of the Caucasus are recognized: the Middle Miocene (15–13 Ma), the Late Miocene (9–5 Ma), the Pliocene (4.5–1.6 Ma), and the Quaternary (less than 1.5 Ma). However, for certain areas the time limits of these stages were shifted relative to each other and overlap the whole age range from the mid-Miocene to the end of the Quaternary period. Therefore, within the collision zone, the Neogene-Quaternary magmatism evolved almost continuously during almost the last 9 m. y., but in the time interval of 13–9 Ma in the Caucasian segment, volcanic activity was possibly low. No evidence of directed lateral migration of volcanic activity within the entire Caucasus region was found. At the same time, in the Lesser Caucasus the young magmatism commenced earlier (∼15 Ma), compared to the Greater Caucasus (∼8 Ma).

Từ khóa


Tài liệu tham khảo

I. V. Chernyshev, M. M. Arakelyants, V. A. Lebedev, et al., Dokl. Earth. Sci. 367A(6), 862 (1999). V. A. Lebedev, I. V. Chernyshev, A. S. Avdeenko, et al., Dokl. Earth. Sci. 409A(4), 1070 (2006). V. A. Lebedev, S. N. Bubnov, I. V. Chernyshev, et al., Dokl. Earth. Sci. 406(1), 37 (2006). E. V. Arutyunyan, V. A. Lebedev, I. V. Chernyshev, et al., Dokl. Earth. Sci. 416(5), 1042 (2007). V. A. Lebedev, S. N. Bubnov, I. V. Chernyshev, et al., Geochemistry International 47(6), 550 (2009). V. A. Lebedev, I. V. Chernyshev, A. V. Chugaev, et al., Geochemistry International 48(1), 41 (2010). V. A. Lebedev, E. V. Sharkov, M. Keskin, et al., Dokl. Earth. Sci. 433(4), 1031 (2010). I. V. Chernyshev, V. A. Lebedev, S. N. Bubnov, et al., Dokl. Earth. Sci. 436(1), 102 (2011). Izmenenie okruzhayushchei sredy i klimata: prirodnye i svyazannye s nimi tekhnogennye katastrofy (Changes of Environment and Climate: Natural and Related Anthropogenic Catastrophes), Ed. by N.P. Laverov (IFZ RAN, Moscow, 2008), Vol. 2. J. R. Pohl, J. C. Hess, B. Kober, et al., in Magmatizm riftov i skladchatykh poyasov (Magmatism of Rifts and Fold Belts) (Nauka, Moscow, 1993), pp. 108–125. J. C. Hess, H. J. Lippolt, A. G. Gurbanov, et al., Earth Planet. Sci. Lett. 117(3/4), 393–406 (1993). A. M. Borsuk, Mezozoiskie i kainozoiskie magmaticheskie formatsii Bol’shogo Kavkaza (The Mesozoic and Cenozoic Magmatic Rock Associations of Greater Caucasus) (Nauka, Moscow, 1979). C. A. Gazis, M. Lanphere, H. P. Taylor, et al., Earth Planet. Sci. Lett. 134, 377–391 (1995).