--> Abstract: New Data on the Geological Structure of the East Arctic Seas Shelf, by Nikolay Sobolev; #90177 (2013)

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New Data on the Geological Structure of the East Arctic Seas Shelf

Nikolay Sobolev

New data were obtained as a result of field work on the New Siberian Islands in 2011 (CASP 2011), 2012, and regional seismic investigations on the shelf of the Laptev, East Siberian, and Chukchi seas. Analysis of these materials leads to the conclusion: 1. The following features can be distinguished on the East Arctic seas shelf from the south to the north: - Early Cretaceous Chukchi-New Siberian orogen; - area of the Precambrian (Baikalian) consolidation, which is traced from the New Siberian Islands to Wrangel Island; - Epicaledonian platform consisting of: southern North Chukchi basin made up by a thick complex of the Paleozoic (Carboniferous-Permian) – Mesozoic deposits, and the northern Precambrian massif (Arctida). 2. De Long Archipelago is not an independent structure of the Caledonian consolidation, as previously thought, but jointly with the Anjou Archipelago (except for Belkovsky Island) it forms a single continental block of the Precambrian (Baikalian) consolidation. The following structures are distinguished in the upper crust of the De Long-Anjou continental block: Baikalian crystalline basement, intermediate Paleozoic-Mesozoic folded complex, and the Early Cretaceous (Aptian-Albian) – Cenozoic sedimentary cover. Folding displacements of the intermediate complex formed as a result of two folding phases: Ellesmerian and Late Cimmerian. 3. Structures of the Verkhoyansk folded complex continue to the Laptev Sea Shelf. The boundary between the Precambrian De Long - Anjou continental block and the Verkhoyansk structures of the Laptev Sea Shelf runs along the west coast of Kotelny Island. 4. Structural-tectonic observations carried out at Belkovsky Island confirm the rift nature of the young post-folding basins on the Laptev Sea Shelf. 5. The following stages are distinguished in the geodynamic evolution of the East Arctic shelf: - the Caledonian basin formed during the Cambrian-Ordovician north of the New Siberian Islands; - in the Late Devonian, the Caledonian basin closed; the South Anyuy oceanic basin formed simultaneously. In the Late Devonian, the De Long - Anjou continental block separated from the Siberian Platform and, from that time trough the Early Cretaceous, the East Arctic Shelf area was the northern continental margin of the South Anyuy Ocean. It is important to note that the terrigenous removal to this continental margin originated from the north, from Arctida; - at the end of the Early Cretaceous, the South Anyuy Ocean closed, while collision processes in the south and south-west of the modern East Arctic Shelf were accompanied by syncollision rifting in the more northern areas; - a new stage of rifting, especially evident in the Laptev Sea shelf is observed in the Cenozoic.

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