Sea level evolution of Laptev and East Siberian Sea - evidence from geological data and glacial isostatic adjustment

• Main Authors: Klemann, Volker, Heim, Birgit, Wetterich, S., Opel, T., Bauch, Henning
• Format: Conference Object
• Language: unknown
• Published: GeoUnion Alfred-Wegener-Stiftung 2014
• Subjects: East Siberian Sea; Laptev Sea; New Siberian Islands; laptev
• Online Access: https://oceanrep.geomar.de/id/eprint/27666/

Laptev Sea and East Siberian Sea are extended shallow shelf seas which were partly land-fallen during glaciated times where the global mean sea level (GMSL) was about -120 m below its present value. At the same time tectonic activity is present, which is evident in uplifted marine terraces of the New Siberian Islands. The marine terraces may be identified and mapped in historical airborne photographs and recent radar imagery. To improve the environmental history of this region a reconstruction of the sea level and shore line migration is necessary which is based on modelling the glacial isostatic adjustment (GIA) including levering. GIA describes the deformational response of the solid earth to the glacially related water-mass redistribution, whereas levering only describes the deformational response of the solid earth to the varying ocean load. For these shallow seas, we expect a deviation from the GMSL between +10 and +30 m by levering alone and due to the vicinity to the Pleistocene ice sheets a further correction at the order of +10 m. These mechanisms reduce therefore the GMSL drop of sea level between 10 and 30 % at last glacial maximum and markedly influence the following evolution of sea level. The variability is dominated by the rheological earth structure considered in the modelling. As the limited knowledge of the rheological earth structure hinders realistic predictions of GIA for this region we will first discuss the variability of sea level history due to GIA for the last 20,000 yr. Then, we will constrain the model dependent variability by consideration of geological proxies of sea level change for this region. Analyses on Laptev Sea sediment cores will reveal a detailed chronology of changing water masses linked to sea level rise.