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 drille d off western Svalbard. The data include grain-size distribution, bulk mine ralogy, clay mineralogy, total carbon, total organic carbon and carbonate d eterminations from over 500 samples. The results show interesting trends ac ross the seismic sequence boundaries defined earlier and can be related to changes in climate and depositional styles. The interpretation of these res ults together with the seismic observations and interpretations made earlie r have shed new light on the timing of the onset of major glaciations and s edimentary processes on the Svalbard Margin during Plio-Pleistocene. The es timate 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 f or the sediments in the 2.3-1.6 Ma interval followed by Svalbard as the mai n sediment source in the post-1.6 Ma interval. It is also suggested that in view of their morphology and proposed sedimentary processes the sedimentar y wedges off Svalbard-Barents Sea Margin are better described as slope apro ns than in terms of 'glacial fans' or 'trough mouth fans' used earlier in t he literature. (C) 2000 Elsevier Science B.V. All rights reserved.