Deciphering late Cenozoic development of the western Svalbard margin from ODP site 986 results

The present work is based on sedimentological data from ODP Site 986 drilled off western Svalbard. The data include grain-size distribution, bulk mineralogy, clay mineralogy, total carbon, total organic carbon and carbonate determinations from over 500 samples. The results show interesting trends across the seismic sequence boundaries defined earlier and can be related to changes in climate and depositional styles. The interpretation of these results together with the seismic observations and interpretations made earlier have shed new light on the timing of the onset of major glaciations and sedimentary processes on the Svalbard Margin during Plio-Pleistocene. The estimate for the timing of the first major glacial advance is revised to 1.6 Ma from the earlier estimate of 2.3 Ma. Barents Sea was the likely source for the sediments in the 2.3-1.6 Ma interval followed by Svalbard as the main sediment source in the post-1.6 Ma interval. It is also suggested that in view of their morphology and proposed sedimentary processes the sedimentary wedges off Svalbard-Barents Sea Margin are better described as slope aprons than in terms of 'glacial fans' or 'trough mouth fans' used earlier in the literature. (C) 2000 Elsevier Science B.V. All rights reserved.