Glacial Dynamics and Deglaciation Pattern of the Svalbard ice Sheet From Seafloor Morphology

The configuration and dynamics for the Svalbard Ice Sheet (SIS) have been reconstructed on the basis of detailed and regional bathymetric data acquired in the fjords and continental shelf of Svalbard. The main drainage routes along the margins of the former Svalbard Ice Sheet have been identified as the major fjords and their connected cross-shelf troughs that extend to the shelf edge. On the west coast of Svalbard four major ice sheet outlet systems existed; Hornsund and Hornsundrenna, Bellsund (Van Keulen/Van Mijen), Isfjorden and Isfjordrenna, Kongsfjorden and Kongsfjordrenna. Along the northern Svalbard margin three major systems exist; Woodfjorden-Moffenrenna, Wijdefjorden-Hinlopenstredet and Kvitoyrenna. Storfjorden drained the southern and eastern part of the Svalbard Ice Sheet as well as parts of Barentsoya and Edgeoya and parts of the northeastern Barents Sea Ice Sheet. In the cross-shelf troughs an extensive pattern of glacial lineations record fast ice flow or palaeo-ice streams. Lateral ice stream moraines several tens of kilometres in length have been mapped along the margins of some of these cross-shelf troughs, identifying the border zone between fast ice flow and stagnant or slow-flowing ice on intervening shelf banks. A grounding zone for the SBIS has been mapped on the shelf edge some 10-20 km off the NW Svalbard coast. The grounding zone probably locates the maximum position of the SIS during the LGM, and shows that the LGM glaciers did not enter the adjacent Yermak Plateau. A large system of retreat moraines on the shallow bank areas on the shelf west and north of Svalbard have been mapped. The moraines are largely parallel with the coast line, and based on these ridges and the general sea floor morphology a new model for the deglaciation of western Svalbard is suggested.