HR: 1340h
AN: T13D-1581    [Abstracts]
TI: RECENT RUSSIAN GEOPHYSICAL AND GEOLOGICAL INVESTIGATIONS ON SIBERIAN CONTINENTAL MARGIN
AU: * A., P V
EM: vap@vniio.nw.ru
AF: VNIIO, Angliyski 1, St.Petersburg, 190121, Russian Federation
AU: D., K V
EM: kaminsky@vniio.ru
AF: VNIIO, Angliyski 1, St.Petersburg, 190121, Russian Federation
AU: V., B V
EM: vicb@vniio.nw.ru
AF: VNIIO, Angliyski 1, St.Petersburg, 190121, Russian Federation
AB: In July-August, 2005 new geophysical and geological data were acquired in the Mendeleev Rise (MR) region during "Arctic-2005" cruise aboard M/V "Akademik Fedorov". The study was concentrated in the southern part of MR in the area of its junction with East Siberian shelf. On-ice deep seismic sounding investigations (with offsets up to 250 km) and helicopter-supported seismic reflection soundings were performed along 600 km-long sub- longitudinal profile. Seismic survey was accompanied by on-ice gravity observations and geological sampling. Air-borne magnetic and air gravity measurements at scale 1:1,000,000 were also performed within a 100 km- wide corridor along the central seismic profile. Processing and analysis of new evidence included the compilation of deep seismic section, 2D seismic-gravity modeling of the Earth crust, 3D modeling of basement and Moho relief, and estimation of sediment and earth crust thickness. The results were integrated with earlier data and used for advanced structural and tectonic interpretations. The following main conclusions were obtained: Thickness of sediment cover along seismic line varies from 12 km in the south (in the North-Chukchi Trough) to 3-4 km in the northern MR. Crust thickness beneath MR is on the order of 30-35 km with a maximum value of 38 km in its southern part. The thinnest crust (28 km) is observed in the North-Chukchi Trough. Potential fields indicate existence of several blocks differing in gravity and magnetic anomalies. In the southern MR these blocks appear separated by grabens and display distinct continental characteristics accentuated by thickness of the crust, its seismic velocities and potential field pattern. At some of the shallowest (possibly eroded?) bathymetric highs the results of bottom sampling seem to point to the possibility of local derivation of coarse bottom debris. The proposed tectonic model implies structural continuity between MR and the adjacent East Siberian shelf. Brief information about the latest Russian geophysical and geological cruise "Arctic-2007" to the Lomonosov Ridge and its transition to the Siberian shelf will also be presented.
DE: 3025 Marine seismics (0935, 7294)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting