--> Abstract: Jura-Cretaceous Syn-orogenic Basin, Western Chukotka, by Elena Vatrushkina; #90177 (2013)

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Jura-Cretaceous Syn-orogenic Basin, Western Chukotka

Elena Vatrushkina

Key words: Western Chukotka, Jura-Cretaceous basin, provenance Studied region is situated in Western Chukotka, in Northeast Russia. We examine the south-western part of the Arctic Alaska - Chukotka microplate. The Upper Jurassic - Lower Cretaceous basins are located on the south-western part of Chukotka terrane. The Chukotka terrane is represented mostly by Paleozoic and Mesozoic deposits of passive continental margin. Triassic and Jurassic-Cretaceous deposits were formed in different geodynamic and paleogeographic environments. For the Triassic turbidite complex is fixed south (modern coordinates) direction of clastic material and metamorphic rocks in the source (Tuchkova, 2009). Lower Jurassic sedimentary rocks are located only on a narrow area, on the left bank of the Rauchua river. Middle Jurassic deposits are absent (Gorodinskiy, 1963). Sedimentary rocks sequences are intruded by post-collision plutons dated by U-Pb (SHRIMP-RG) - 115-117 Ma (Katkov, 2010). We attempted to compile and synthesize available information on all of the Jurassic-Cretaceous basins of the Chukotka terrain. This report presents the results of a study sedimentological data Kitepveem, Rauchua, Pevek and Upper Pegtymel depressions obtained in field work in 2003, 2004, 2006, 2010 and 2011. The main object is to understand the evolution of deposition during the Jurassic and Cretaceous in the study region. Was there a single basin or were several isolated basins that have had different sources and directions of transportation. Starting from Oxford in the south-western margin of the Chukotka terrane, simultaneously with collision of Eurasia and Arctic Alaska - Chukotka microplate and closure of the South Anyui ocean, a number of isolated basins with local sources are formed. Deposits of Pevek, Rauchua and Kitepveemskoy depressions, have similar sources, direction of transportation material and the depositional environment. Most likely they were accumulated in a single syn-orogenic basin by gravity flow. Measurements of slumping folds indicate that sediments were transported from south to north (modern coordinates). In the area of erosion are located Precambrian granitoids, island arc volcanic rocks and Upper Triassic clastic rocks. Deposits of Upper Pegtymel depression were accumulated in a small isolated basin. These sedimentary rocks had other sources and were deposited under the influence of gravity flow. Their composition was dominated by Triassic clastic rocks and Late Mesozoic acid igneous rocks. Granites placed at the distance from the area of sedimentation. This work was funded by the RFBR project 11-05-00787a, 12-05-31432 and scientific school SS-5177.2012.5

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