Glacial dynamics and deglacial retreat pattern in fingerdjupet trough, western barents sea

QUATERNARY SCIENCE REVIEWS

卷:243

Article

Jakobsen, Frank Werner¹  Bjarnadottir, Lilja Run¹  Boe, Reidulv¹ 

[1] Geol Survey Norway NGU, Postal Box 6315 Torgarden, N-7491 Trondheim, Norway

关键词: Deglaciation;    Ice stream;    Glacial dynamics;    Glacial geomorphology;    Ice sheet reconstruction;    Spitsbergenbanken;    Barents sea ice sheet;   

DOI  :  10.1016/j.quascirev.2020.106457

来源: Elsevier

【 摘 要 】

New high-resolution multibeam bathymetry and sub-bottom profile datasets from Fingerdjupet are used for the first detailed geomorphological mapping of the seafloor in this area. The mapped landforms provide evidence for a palaeo-ice stream flowing in a southeasterly direction from Spitsbergenbanken into Fingerdjupet, merging with Bjornoyrenna ice stream, and confirm a theorised palaeo-ice divide located along the bank. The combined landform records and acoustic stratigraphy allow a detailed reconstruction of the glacial dynamics during the last deglaciation. The withdrawal of the Fingerdjupet ice stream from Bjornoyrenna was characterised by rapid retreat, punctuated by periods of stable ice marginal conditions. Five to six major ice margin stillstands and/or readvances associated with the last deglaciation are identified in the seafloor record and acoustic stratigraphy. During these events, large grounding zone wedges were deposited at the ice stream margin. The seabed geomorphology indicates that ice stream dynamics changed as the ice stream retreated from the trough onto the shallower bank. Here, numerous retreat moraines indicate that a grounded ice margin retreated slowly, with several minor stillstands, towards north-northwest. Several controls and/or drivers on the style of ice flow and retreat have been suggested, including catchment size reduction, sea level rise, bedrock topography, drawdown of bank ice and/or migration of the main ice divide over the bank. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

Free