HR: 1340h
AN: C13A-0264    [Abstracts]
TI: High Resolution Multichannel Seismic Images of Marine Permafrost - First Results from TRANSDRIFT X Cruise to the Laptev Sea
AU: Schwenk, T
EM: tschwenk@uni-bremen.de
AF: Dept. of Geosciences, University of Bremen, P.O. Box 330440, Bremen, 28334 Germany
AU: * Spiess, V
EM: vspiess@uni-bremen.de
AF: Dept. of Geosciences, University of Bremen, P.O. Box 330440, Bremen, 28334 Germany
AU: Z�hlsdorff, L
AF: Dept. of Geosciences, University of Bremen, P.O. Box 330440, Bremen, 28334 Germany
AU: Voigt, T
AF: Dept. of Geosciences, University of Bremen, P.O. Box 330440, Bremen, 28334 Germany
AU: Belan, A
AF: Moscow State University, Moscow, Moscow, 00000 Russian Federation
AU: Belan, A
AF: Otto Schmidt Laboratory for Polar and Marine Sciences at the State Research Center for Antartctic and Arctic Research, St. Petersburg, St. Petersburg, 00000 Russian Federation
AU: Gusev, Y
AF: VNIIO All Russian Research Center for Geology of the World Ocean, St. Petersburg, St. Petersburg, 00000 Russian Federation
AU: Gusev, Y
AF: Otto Schmidt Laboratory for Polar and Marine Sciences at the State Research Center for Antartctic and Arctic Research, St. Petersburg, St. Petersburg, 00000 Russian Federation
AU: Rekant, P
AF: VNIIO All Russian Research Center for Geology of the World Ocean, St. Petersburg, St. Petersburg, 00000 Russian Federation
AU: Rekant, P
AF: Otto Schmidt Laboratory for Polar and Marine Sciences at the State Research Center for Antartctic and Arctic Research, St. Petersburg, St. Petersburg, 00000 Russian Federation
AU: Hoelemann, J
AF: Alfred-Wegener Institut f�r Polar- und Meeresforschung, Bremerhaven, Bremerhaven, 28338 Germany
AU: Kassens, H
AF: Leibniz Institut fuer Meereswissenschaften (IfM-GEOMAR), Kiel, Kiel, 24117 Germany
AB: Large areas of the shallow shelf seas in the Siberian Arctic were exposed in glacial times and thereby subject to climatic conditions supporting the development and growth of permafrost. However, it is unclear, how the cyclic occurrence of transgressions and regressions have effected the presence and distribution of permafrost in the currently drowned shelf areas. As part of the Laptev Sea System' Project carried out in close partnership between German and Russian Research institutions, the TRANSDRIFT X cruise with R/V Smirnitsky was undertaken inSeptember 2004 to survey off-shore permafrost in the eastern Laptev Sea with a combination of acoustic and seismic systems, namely side scan sonar, chirp sonar and the new shallow marine multichannel seismic system FlaMMe of the University of Bremen. It was of particular interest to detect the top of the permafrost zone to analyze the stability of permafrost after the Holocene transgression to use the collected data for a drilling campaign planned for summer 2005. The MCS system consists of a 48-channel single hydrophone streamer of 50 m length with 5 cable levellers and additional 9 depth sensors built into the streamer to allow a superior geometry control and towing at very shallow depth of appx. 1 m. A SODERA Mini GI Gun and a SODERA S-15 Watergun were used to generate high frequency signals beyond the conventional seismic frequencies, which ranges between 100 and 500 and between 200 and 1600 Hz, respectively. Examples will be shown from areas near the coast, where the former thermokarst surface was nearly undestroyed by the transgression, as well as a region northeast of the Lena delta, where an unconformity indicated the transgressive reworking of the terrestrial landscape. Further targets are thermokarst structures like pingos or thermokarst lakes with associated taliks, the distribution of marine Holocene sediments and the permafrost degradation with respect to the location of the paleoriver valleys. Combined analyses of the acoustic data sets collected will allow detailed studies on the preservation state of permafrost in the southern Laptev Sea area.
DE: 4207 Arctic and Antarctic oceanography
DE: 3020 Littoral processes
DE: 3025 Marine seismics (0935)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting