--> Abstract: Upper Paleozoic Sediments of North-Eastern Siberia and the Belkovsky Island (New Siberian Islands): Depositional Settings and Provenance, by Victoria Ershova; #90177 (2013)

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Upper Paleozoic Sediments of North-Eastern Siberia and the Belkovsky Island (New Siberian Islands): Depositional Settings and Provenance

Victoria Ershova

Relationship between the Siberian Craton and its deformed passive margin (Verkhoyansk fold and thrust belt) with the New Siberian Islands has long been discussed. Our study of the Upper Paleozoic succession from both areas shows significant similarity in their depositional history. In northern Siberia, Devonian and lowermost Carboniferous strata are mainly carbonates with minor addition of clastics deposited in the wide epicontinental basin. The abrupt shift to clastic sedimentation occurred in the Visean. Since that time clastic sedimentation prevailed in the northern part of the Siberian Craton and its passive margin. Deposition of the Carboniferous-Permain succession occurred mainly in deltaic and prodelta environments with transition to submarine fan environments. Significantly increasing sedimentary supply in the Early Carboniferous was probably related to the appearance of new source areas along the boundaries of the Craton. The Upper Paleozoic succession of Belkovsky Island comprises Upper Devonian carbonates and Carboniferous and Permian(?) clastic deposits. The Devonian bituminous carbonates formed on the carbonate platform in environments similar to those in northern Siberia, but in a deeper part of the shelf basin. The overlying Carboniferous and Permian (?) clastic rocks are very similar to correlative rocks from northern Siberia and were deposited in similar depositional environments. To identify provenance of clastic sediments we did U-Pb detrital zircon study of 4 samples of Carboniferous sandstones from the northeastern Siberian Craton and its passive margin. All samples show similar age distribution, although there are some variations in abundance of each population. Zircons of Palaeoproterozic-Archean, Neoproterozoic and Devonian-Early Carboniferous ages are most widespread, whilst Early Paleozoic ages constitute an insignificant portion. The broad spectrum of age ranges within individual samples indicates that clastic material was derived from multiple sources, including crystalline basement and sedimentary cover of the Siberian Craton with significant addition from the Taimyr and/or Altay-Sayan orogenic belts. Study of three samples from Belkovsky Island is in progress. Study by V.Ershova, A.Prokopiev and A.Khudoley was partly supported by RFBR projects 12-05-33018, 13-05-00700 and TGS-NOPEC Geophysical Company.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013