Onset and growth of Trough-Mouth Fans on the North-Western Barents Sea margin - implications for the evolution of the Barents Sea/Svalbard Ice Sheet

The aim of this study is to discuss the onset and growth of the Bellsund, Hornsund and Storfjorden Trough-Mouth Fans (TMFs) on the North-Western Barents Sea margin. This is done on the basis of a seismo-stratigraphic analysis of new 2D seismic reflection profiles, and a new correlation between ODP Site 986 west of Spitsbergen and the seismo-stratigraphic network in the central part of the Western Barents Sea margin. We infer that reflector R4A marks the onset of both the development of the TMFs and the contourite deposition which dominate this part of the margin from this time onward. We conclude that these deposits were frequently affected by episodes of small-scale mass-wasting, focused at the mouth of the glacially eroded cross-shelf troughs. With a new interpolation between the few available constraints, we propose an age of about 1.3 Ma for the onset of both the development of the TMFs and the contourite deposition. Thus, we hypothesize, from our results and from previous studies, that the Barents Sea/Svalbard Ice Sheet expanded first beyond the coast north of Svalbard, later reaching the shelf edge at the mouth of Bjørnøyrenna and then to Storfjorden/southern Spitsbergen.