Geochemical peculiarities and genesis of metaandesites and metadacites of the Novogorovka greenstone structure (Ukrainian Shield)
DOI:
https://doi.org/10.15407/dopovidi2017.04.049Keywords:
greenstone structure, komatiite-tholeiitic formation, metaandesite, metadacite, Ukrainian ShieldAbstract
Metaandesites of tholeiitic series of parageneration KT-3 of metamorphosed komatiite-tholeiitic formation of Novogorovka GS can be formed as a result of the fractional crystallization of mafic magma from a plume source in the shallow magma chamber (<40 km). They have a low magnesium number (mg# = 0.32). Metadacite located among the rocks of the parageneration of KT-3 were formed in a different magmatic source and are likely more recent. They belong to the calc-alkaline series, are characterized by high magnesium number (mg# = 0.51) and strongly contaminated by a crustal material. Metadacite can be formed by mixing melts of the mafic and silicic compositions or by assimilation of host rocks by basites in a shallow magma chamber (<40 km).
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Lobach-Zhuchenko, S. B. (Ed.). (1988). Greenstone belt of basement of the East European Platform (Geology and Petrology of volcanic rocks). Leningrad: Nauka (in Russian).
Artemenko, G. V. (1999). The conditions for the generation of volcanic rocks of intermediate and acid composition in the greenstone belts of the Ukrainian shield. Dopov. Nac. akad. nauk Ukr., No. 11, pp. 112-116 (in Russian).
Kuno, H. (1968). Origin of andesite and its bearing on the Island arc structure. Bull. Volcanol., 32, Iss. 1, pp. 141-176. https://doi.org/10.1007/BF02596589
Barnes, S. J. & Van Kranendonk, M. J. (2014). Archean andesites in the east Yilgarn craton, Australia: products of plume-crust interaction? Lithosphere, 6, No. 2, pp. 80-92. https://doi.org/10.1130/l356.1
Bobrov, O. B. (2015). The Greenstone structure Orekhov-Pavlograd zone: first experience of geological description. Article 1. Novogorovka structure. Mineral. zhurn., 37, No. 4, pp. 68-77 (in Ukrainian).
Shcherbak, N. P., Artemenko, G. V., Nekryach, A. I. & Zhdanov, E. N. (1992). Age of metavolcanics of Novogorovka greenstone structure (West Azov block). Dokl. AN Ukr., No. 9, pp. 102-104 (in Russian).
Sun, S. S. & McDonough, W. F. (1989). Chemical and isotopic systematic of oceanic basalts: implications for mantle composition and processes. Magmatism in the Ocean Basins. Geol. Soc. Spec. Publ., No. 42, pp. 313-345. https://doi.org/10.1144/GSL.SP.1989.042.01.19
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