The Late Weichselian glaciation of the Franz Victoria Trough, northern Barents Sea: ice sheet extent and timing

High resolution seismic profiles (PARASOUND, 4 kHz) and three sediment cores from the Franz Victoria Trough and the adjacent continental slope were studied in order to constrain the timing and extent of the northern Svalbard/Barents Sea ice sheet during the Late Weichselian glaciation. Stacked debris flow lobes and layers of glacimarine diamicton on the lower continental slope indicate that large quantities of glacially derived sediments were deposited by the northern Svalbard/Barents Sea ice sheet directly onto the upper continental slope at approximately 23 (14)C ka. A grounding-line advance to the shelf break is supported by the identification of diamicton, interpreted as till, in the seismic profile near the shelf break. After several ice sheet instabilities marked by significant input of ice rafted detritus to the continental margin, the disintegration of the northern Svalbard/Barents Sea ice sheet (Termination la) is indicated by a distinct pulse of ice rafted detritus at 15.4 (14)C ka and the transition to an isotopically defined meltwater signal. The drastic change in sedimentary pattern on the upper continental slope, dared to about 13.4 (14)C ka, is interpreted as grounding-line retreat from the shelf edge. A further stepwise retreat of the northern Svalbard/Barents Sea ice sheet is indicated by pulses of ice rafted detritils which appear to be contemporaneous with the onset of distinct ice rafting events in adjacent areas and pulses of glacimarine sedimentation in the southwestern Barents Sea. (C) 2000 Elsevier Science B.V. All rights reserved.