Email this article Petrological-Geochemical Characteristics of Lavas, Sources and Evolution of Magmatic Melts of the Kazbek Neovolcanic Center (Greater Caucasus)
- Authors: Parfenov A.V.1, Lebedev V.A.1, Chernyshev I.V.1, Vashakidze G.T.2, Yakushev A.I.1, Goltsman Y.V.1, Chugaev A.V.1, Oleinikova T.I.1, Kanunnikova E.M.1, Gabarashvili K.A.2
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Affiliations:
- Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
- A. Janelidze Institute of Geology, I. Javakhishvili Tbilisi State University
- Issue: Vol 27, No 6 (2019)
- Pages: 606-632
- Section: Article
- URL: https://journals.rcsi.science/0869-5911/article/view/177766
- DOI: https://doi.org/10.1134/S0869591119060043
- ID: 177766
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Abstract
The results of petrological-geochemical and isotope-geochemical studies of the Late Pleistocene-Holocene lavas of the Kazbek neovolcanic center, one of the largest centers of youngest magmatism in the Greater Caucasus, are presented. It has been established that the volcanic rocks of the Kazbek center form a continuous compositional series basaltic (trachy-)andesites–(trachy-)andesites–dacites with a predominance of calc-alkaline intermediate and moderately-acid lavas. The obtained results indicate that fractional crystallization and mixing of melts had a leading role in the petrogenesis of the rocks. The crustal assimilation was of limited importance; its influence is noticeable only in the rocks of the earliest and late pulses of magmatic activity within the Kazbek center. The common crustal lithologies participating in the assimilation were metamorphosed Jurassic sediments (mainly shales and sandstones) forming the base of the Kazbek center and rarely Mesozoic mafic metamorphosed volcanites. The specific features of AFC processes during the development of the studied magmatic system (including the presence of noticeable amount of water in the melt, the leading role of Amp in the cumulus and the absence of Pl fractionation) led to the appearance of dacitic lavas with geochemical signs of adakites as an evolutional end-member. The volcanic rocks of the Kazbek center are derived from trachybasalt magmas, the source of which was presented by the mantle reservoir of OIB-type. Recent and previously published results of studies of the Neogene-Quaternary magmatism manifested within the Greater Caucasus show that the main petrological and geochemical characteristics of this regional mantle reservoir remained constant from the end of the Miocene to the present time.
About the authors
A. V. Parfenov
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Author for correspondence.
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
V. A. Lebedev
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
I. V. Chernyshev
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
G. T. Vashakidze
A. Janelidze Institute of Geology, I. Javakhishvili Tbilisi State University
Email: kvarcz@yandex.ru
Georgia, A. Politkovskaya st., 5, Tbilisi, 0186
A. I. Yakushev
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
Yu. V. Goltsman
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
A. V. Chugaev
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
T. I. Oleinikova
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
E. M. Kanunnikova
Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences
Email: kvarcz@yandex.ru
Russian Federation, Staromonetny per. 35, Moscow, 119017
K. A. Gabarashvili
A. Janelidze Institute of Geology, I. Javakhishvili Tbilisi State University
Email: kvarcz@yandex.ru
Georgia, A. Politkovskaya st., 5, Tbilisi, 0186
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