TY - JOUR

T1 - Metasedimentary rocks of the paleoarchean Dniester-Bug Group, Ukrainian Shield

T2 - Composition, age, and sources

AU - Lobach-Zhuchenko, S. B.

AU - Balagansky, V. V.

AU - Baltybaev, Sh K.

AU - Artemenko, G. V.

AU - Bogomolov, E. S.

AU - Yurchenko, A. V.

AU - Stepanyuk, L. M.

AU - Sukach, V. V.

N1 - Funding Information: ACKNOWLEDGMENTS This work was supported by the State Foundation for Basic Research of Ukraine (project no. F40.6/029 “Early Precambrian Supracrustal Complex of the Ukrainian and Baltic Shields as Indicators of the Main Stages and Geodynamic Formation Conditions of the Continental Crust of the East European Platform in the Archean and Paleoproterozoiz”) and the Russian Foundation for Basic Research (project no. 09 05 00160 Ukr_a).

PY - 2014/9

Y1 - 2014/9

N2 - Paleoarchean granulite-facies metasedimentary rocks (quartzites, garnet quartzites, garnet-pyroxene gneisses, pyroxene-magnetite and magnetite quartzites) attributed to the Dniester-Bug Group of the Ukrainian Shield were studied. On the basis of geochemical data, including REE, the primary composition of these rocks was reconstructed as association of Fe-rich sandstones and sublitharenites, Fe-shales, and BIFs. This sedimentary association is similar to the rocks of other ancient greenstone belts and ascribed to the Algama-type iron formation. The sum of Al2O3, CaO, Na2O, and TiO2, high Zr contents (>100 ppm in quartzites), and the presence of detrital zircon grains of different ages are consistent with the terrigenous nature of sedimentary rocks. The Sm/Nd, Ti/Zr, Sc/Zr, and Ni/Zr ratios indicate the predominance of granitoid rocks in the source areas. The elevated Cr contents suggest that, in addition to granitoids, the source area contained ultramafic rocks. Geochemical characteristics, such as Fe/Mn ratio, low REE contents, and variations of REE versus the sum of Ni, Co, and Cu testify that sedimentation occurred under shallow-water conditions on the continent or its slope, similarly as the formation of ancient (3.5-3.2 Ga) basalt-komatiitic series intercalated with sedimentary rocks in the Pilbara Craton. The age of supracrustal rocks of the Dniester-Bug Group was constrained within the time interval of 3.4-3.2 Ga on the basis of U-Pb zircon dating and determination of Nd isotope composition. The DM model age of quartzites varies from 3.37 to 3.5 Ga. Sedimentary rocks together with volcanic rocks represent the oldest supracrustal association of the East European Platform.

AB - Paleoarchean granulite-facies metasedimentary rocks (quartzites, garnet quartzites, garnet-pyroxene gneisses, pyroxene-magnetite and magnetite quartzites) attributed to the Dniester-Bug Group of the Ukrainian Shield were studied. On the basis of geochemical data, including REE, the primary composition of these rocks was reconstructed as association of Fe-rich sandstones and sublitharenites, Fe-shales, and BIFs. This sedimentary association is similar to the rocks of other ancient greenstone belts and ascribed to the Algama-type iron formation. The sum of Al2O3, CaO, Na2O, and TiO2, high Zr contents (>100 ppm in quartzites), and the presence of detrital zircon grains of different ages are consistent with the terrigenous nature of sedimentary rocks. The Sm/Nd, Ti/Zr, Sc/Zr, and Ni/Zr ratios indicate the predominance of granitoid rocks in the source areas. The elevated Cr contents suggest that, in addition to granitoids, the source area contained ultramafic rocks. Geochemical characteristics, such as Fe/Mn ratio, low REE contents, and variations of REE versus the sum of Ni, Co, and Cu testify that sedimentation occurred under shallow-water conditions on the continent or its slope, similarly as the formation of ancient (3.5-3.2 Ga) basalt-komatiitic series intercalated with sedimentary rocks in the Pilbara Craton. The age of supracrustal rocks of the Dniester-Bug Group was constrained within the time interval of 3.4-3.2 Ga on the basis of U-Pb zircon dating and determination of Nd isotope composition. The DM model age of quartzites varies from 3.37 to 3.5 Ga. Sedimentary rocks together with volcanic rocks represent the oldest supracrustal association of the East European Platform.

UR - http://www.scopus.com/inward/record.url?scp=84906504173&partnerID=8YFLogxK

U2 - 10.1134/S002449021405006X

DO - 10.1134/S002449021405006X

M3 - Article

AN - SCOPUS:84906504173

VL - 49

SP - 381

EP - 397

JO - Lithology and Mineral Resources

JF - Lithology and Mineral Resources

SN - 0024-4902

IS - 5

ER -