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The oldest granulites of the Ukrainian shield, the Bug granulitic complex

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Category: Geology

Last Updated on 04 June 2015

Published on 29 March 2015

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Authors:

S.B. Lobach-Zhuchenko, Dr. Sci. (Geol.-Min.), Professor, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences (IPGG RAS), Chief Researcher, St. Petersburg, Russia

T.V. Kaulina, Dr. Sci. (Geol.-Min.), Geological Institute of the Kola Science Centre, Russian Academy of Sciences (GI KSC RAS), Leading Researcher, Apatity, Russia

V.V. Sukach, Cand. Sci. (Geol.), N.P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation, National Academy of Sciences of Ukraine (IGMOF NASU), Senior Research Scientist, Kiev, Ukraine

А.V. Yurchenko, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences (IPGG RAS), Research Scientist, St. Petersburg, Russia

S.K. Baltybaev, Dr. Sci. (Geol.-Min.), Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences (IPGG RAS), Deputy Director, St. Petersburg, Russia

V.V. Balagansky, Dr. Sci. (Geol.-Min.), Geological Institute of the Kola Science Centre, Russian Academy of Sciences (GI KSC RAS), Head of Laboratory, Apatity, Russia

Abstract:

Purpose. Geological and geochronological study of main stages of granulitic metamorphism in the geological evolution of the Bug granulitic complex of the Ukrainian Shield (USh).

Methodology. The study consisted of field works, laboratory analytical investigations of rock samples and scientific generalization of the obtained data. Rock sampling was fulfilled within in detail described exposures of quarry walls. Laboratory investigations included such methods: rock chemical analysis on main, rare and REE elements; chemical analysis of rock-forming minerals; rare and REE analysis of zircon; studying of an internal structure and measurement of U-Pb isotope relations in zircon (SHRIMP II, VSEGEI, St.-Petersburg).

Findings. We have proved that the studied zircon belongs to granulitic type by its morphology, internal structure and chemical composition. Containing zircon two-pyroxene gneisses answer to P-T parameters of granulitic metamorphic facies on the base of rock-forming minerals composition. Thus, the established radiological zircon age 3499±33 Ma fixes time of the earliest stage of granulitic metamorphism of the Bug rock complex.

Originality. The Paleoarchean granulitic metamorphic facies have been identified in the Bug rock complex for the first time. This data significantly supplements our conceptions about early geological history of USh as a fragment of early Precambrian crust.

Practical value. Practical usage of received results in geological mapping of the Dniester-Bug province will promote more valid metallogenic assessment and increase of prospecting efficiency within this province and USh as a whole.

References:

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4. Stepanyuk, L.M., Gatsenko, V.O. and Lobach-Zhuchenko, S.B. (2013), “High-K mafic dykes of Bug granulitic complex: geological setting, rock composition and age”, Mineral. Journ., V. 35, no. 3, pp. 78–84.

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7. Lobach-Zhuchenko, S.B., Balaganskiy, V.V. and Baltybaev, Sh.K. (2013), “Main development stages of Bug granulitic complex: new structural-petrological and isotopic-geochronological data (Middle Bug region, Ukrainian Shield)”, Mineral. Journ.,V. 35, no. 4, pp. 86–98.

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