Geochemistry of the Osnitsk-Mikashevichy volcanoplutonic complex of the Ukrainian shield

Abstract

This paper addresses the geochemistry of intrusive (Osinitsk complex) and volcanic (Klesov Group) rocks of the Osnitsk-Mikashevichy volcanoplutonic belt (OMVPB) of the Ukrainian shield, which is an active continental margin existing approximately 1980-2000 Ma ago. The Osnitsk complex comprises a wide range of rocks, from ultrabasics to granitoids, and the Klesov Group is dominated by extrusive rocks of basaltic and rhyolitic compositions metamorphosed under epidote amphibolite facies conditions. The Sr-Nd-Hf isotopic systematics (εSr 1990 from -4 to +10, εNd 1990 from -0.6 to +2.3, and εHf1990 from 0.1 to 1.4) indicates a juvenile source for the OMVPB rocks. Geochemical data suggest independent origin of the rocks of gabbroid (SiO 2 < 60 wt %) and granitoid (SiO 2 > 60 wt %) series. The gabbroids are subdivided into pre and post granite groups on the basis of the higher contents of incompatible trace elements and lower contents of compatible elements in the post granite rocks. The geochemical characteristics of the two groups of basic rocks indicate their formation in a convergent tectonic setting. The origin of the granitoid melts is attributed to the low degree (eutectoid) melting of basic rocks at relatively low temperatures.

U-Pb Age and Hf Isotope Systematics of Zircon from Eclogite Xenoliths in Devonian Kimberlites: Preliminary Data on the Archaean Roots in the Junction Zone between the Sarmatian and Fennoscandian Segments of the East European Platform

“…The eastern part of the Prypyat horst belongs to the OMIB [38,39], which is considered to represent a Paleoproterozoic (ca. 2030-1980 Ma) active continental margin [40,41]. The OMIB comprises intrusive rocks ranging in composition from ultrabasics to granitoids (with granitoids being the predominant rock type) and extrusive rocks of basaltic and rhyolitic compositions metamorphosed under epidote-amphibolite facies conditions.…”

“…Both the OMIB and the Teteriv Belt represent juvenile Paleoproterozoic crust formed outboard of the Archean Dniester-Bouh Domain of the Ukrainian Shield, whereas Archean rock complexes are absent in the area. No Archean signature has been revealed in either the OMIB [41] or the Teteriv Belt [75,76]. The lower-crustal xenoliths of feldspar-rich garnet granulites and feldspar-poor eclogitic granulites that geochemically resemble mafic rocks of the OMIB have been also studied [77].…”

Detrital zircon U-Pb and Hf constraints on provenance and timing of deposition of the Mesoproterozoic to Cambrian sedimentary cover of the East European Craton, Belarus

“…The main lithotectonic units of the crystalline basement of Belarus are composed of mediumto high-grade metamorphic rocks of Paleoproterozoic age (Bogdanova et al, 2001;Claesson et al, 2001;Shumlyanskyy, 2014). They run NE-SW, parallel to the c. 1.8 Ga old tectonic suture between Sarmatia and Fennoscandia (Elming et al, 1998;Bogdanova et al, 2008;Lubnina et al, 2009) (Fig.…”

Neoarchean‐Palaeoproterozoic sedimentary basins in the Sarmatian Craton: Global correlations and connections

“…The northeastern boundary of the Sarmatia Craton with the Volga‐Uralia Craton is represented by the vast Volga–Don orogen (Figure 1), which is composed of juvenile Middle Palaeoproterozoic volcano‐sedimentary and plutonic complexes marking island arc (2.20–2.10 Ga), collisional (≈2.07 Ga), and post‐collisional (2.07–2.05 Ga; Bibikova et al, 2009; Savko, Samsonov, & Bazikov, 2011; Savko, Samsonov, Bazikov, & Kozlova, 2014; Savko, Samsonov, Larionov, Larionova, & Bazikov, 2014; Savko, Samsonov, Sal'nikova, Kotov, & Bazikov, 2015; Shchipansky, Samsonov, Petrova, & Larionova, 2007; Terentiev, Savko, & Santosh, 2016; Terentiev, Savko, & Santosh, 2017) tectonic settings (Figure 2). In the north and northwest, the Sarmatia Craton is bounded by the Osnitsk–Mikashevichi volcano‐plutonic belt, which is composed mainly of granite batholiths, diorites, and gabbro with ages in the range of 2.00–1.95 Ga, considered as an active margin of Sarmatia (Claesson et al, 2001; Shumlyanskyy, 2014).…”