History and mechanisms of the Fram Slide, Fram Strait

Abstract:

Submarine slope failures are a widespread phenomenon on continental margins and a potential geo-hazard. Numerous large submarine landslides shaped the northeast Atlantic glaciated margins during the Holocene and Pleistocene. The prevailing understanding is that submarine slides on the glaciated European continental margins are closely related to the extent of ice sheets and the resulting variation in sedimentation rate and type in front of cross shelf troughs during glacial-interglacial climate cycles. Here we report on a newly discovered large landslide complex off northwest Svalbard in the Fram Strait which we have named Fram Slide. There is evidence that this failure is not related to rapid glacigenic debris flow deposition, which is significantly different from many other large Holocene and Pleistocene submarine landslides on the glaciated margins off NW Europe. Our data suggest that it is more likely that a combination of unstable sediments due to contour currents, tectonic movement and/or fluid migration has played a major role in causing the landslide. High-resolution two-dimensional seismic data, multibeam, Parasound and sediment core data constrain the history of the different parts of the slide complex. The Fram Slide complex has been repeatedly active for several 100k years. Together with the observation that it was not directly related to glacial debris flow deposition, this means that the eastern continental margin of the Fram Strait may fail and cause tsunamis without the necessity of a new glaciation.