Environmental history of the Laptev Sea : present status and future perspective.

Bauch, Henning , Kassens, Heidemarie, Klyuvitkina, Tatyana, Meyer, Hanno, Müller-Lupp, Thomas, Polyakova, Yelena, Rekant, Pavel and Taldenkova, Ekaterina (2006) Environmental history of the Laptev Sea : present status and future perspective. [Talk] In: 8. Workshop on Russian-German Cooperation: Laptev Sea System. , 07.02.-09.02.2006, St. Petersburg, Russia .

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Empirical data as well as modelling experiments show that the stability of the Arctic
cryosphere is today under threat due to global warming. Along the circum-arctic ocean periphery this cryosphere is comprised of terrestrial permafrost. However, during
Quaternary times this frozen landscape was repeatedly changed due to global sea-level
fluctuations which particularly affected the wide and shallow Siberian shelves. As western
part of the Beringian landmass the entire Laptev Sea shelf was subaerially exposed in last glacial times. During the ensuing postglacial global sea-level rise this region gradually changed from a terrestrial permafrost landscape into a shallow marine shelf environment. Various geochemical, micropaleontological, palynological, and sedimentological data obtained from both conventional gravity cores and drill cores reveal the strong influence of this tranformation process on the shelf environment.
Our previous scientific drilling campaign (2000), conducted to the outer Laptev Sea
shelf with the goal to recover pre-Holocene sediments from acoustically transparent
sections, confirmed the existence of frozen, and ice-bearing terrestrial sediments below a
soft, marine sediment package of Holocene age. However, oxygen isotope composition of
the ice unveiled that these frozen sediments must have been altered by re-freezing processes during and after the transgression. This assumption seems now corroborated by new high-resolution acoustic data from the mid- to inner shelf region gained during the latest expeditions in 2004.
Although the overall scenario of shelf transformation for the time since the last sea
level rise seems to be reasonably well understood now, there is no information available so far from older climatic intervals with conditions comparable to the Holocene. But such information from Holocene-like climate intervals will contribute useful insight for
predictive purposes, since these records would then provide a longer time frame within which to evaluate natural variability in general, and means to examine the response of the Arctic system to future changes in particular. The Laptev shelf seas is a crucial area for such paleo-evaluation studies due to its highly changeable environment, both seasonally as well as on longer timescales (decadal to millennial to glacial-interglacial).

Document Type: Conference or Workshop Item (Talk)
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: No
Related URLs:
Projects: Laptev Sea System, Permafrost
Date Deposited: 03 Dec 2008 16:52
Last Modified: 23 Sep 2019 22:48
URI: https://oceanrep.geomar.de/id/eprint/187

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