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1) Permafrost Institute, Russian Academy of Sciences,
Yakutsk, Russia 2) Arctic and Antarctic Research Institute, St.
Petersburg, Russia 3) Alfred Wegener Institute, Research Department Potsdam,
Germany 4)
University of Bremen, Institute of Geology, Bremen, Germany
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The coastal and offshore permafrost is poorly studied in the western part
of the Laptevs Sea. Information on distribution of submerged permafrost
and its evolution in this area is almost absent. In this connection
results of sea floor drilling conducted in spring 2005 by joint
Russian-German Expedition «Coast-1» near Mammoth Tusk (Mamontovy Klyk)
Cape, are of great interest. Deposits with negative temperature and fresh ice inclusions occur along
the entire drilling profile 12 kilometers long. The temperature in
boreholes change from -12 in the beach borehole to -1°C in the most
distant offshore borehole. This suggests that that the submerged
permafrost occurs in the form of a horizontal wedge pinching out not far
offshore. The drilling profile reveals terrestrial and marine sedimentary
formations. The marine sediments at the depth of 65 to 77 m according to
the IR-OST dating belong to the Kazantsevo Horizon. The Kazantsevo
shoreline was probably close to the present one. Plastic-frozen marine
sediments were found only in one borehole located at 12 km from the
shoreline. They are covered by terrestrial deposits with ice-sand wedges
and by thawed sediments. The obtained data help to understand the specifics of interaction between permafrost and arctic sea water. They are instrumental in refining permafrost history of the studied area in the Late Pleistocene and Holocene. |
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Reference:
Grigoriev M.N., Kunitsky V.V., Bolshiyanov D.Yu., Rachold V., Junker R. |
