A surging behaviour of glacigenic debris flows

Abstract

Based on industry 3-dimensional seismic data, covering an area of 2,190 km2 of the continental slope offshore mid-Norway, the frontal part of glacigenic debris flow deposits have been studied. The debris flows are up to 6 km wide, 60 m thick and have a length of more than 40 km. Time-slices show that their frontal part is characterized by a zone of front-parallel lineations. The individual lineations are up to some tens of meters wide and they can be followed for several kilometers. In the seismic lines these lineations correspond to dipping reflections, probably formed by sediment compression and thrusting during the final stage of flow. Compression and thrusting implies a surging flow behavior, previously reported from experimental studies of hydroplaning. Thus a surging behavior of the studied flows is inferred to be related to the process of hydroplaning which may lead to surge due to acceleration and detachment of the frontal part from the rest of the flow. Hydroplaning also explains the long run-out of these flows. © Springer Science+Business Media B.V. 2012.