Thick slides dominated by regular-wavelength folds and thrusts in biosiliceous sediments on the Vema Dome offshore of Norway

Three-dimensional seismic reflection data image four submarine slides on the flanks of the Vema Dome in the Vøring Basin. Each one covers an area of ~ 30 km2, is several hundred metres thick, and hosted in biosiliceous sediments. The topography the upper surface of each slide consists of a series of regular-wavelength arcuate ridges (and associated troughs), perpendicular to the dip of the slope, that correspond to internal fold and thrust structures. Thrusts probably propagated retrogressively based upon the observation that fold amplitudes decrease upslope. The slides lack clearly defined head-scarps, and the magnitude of shortening accommodated by the folding indicates short transport distances. The spatial co-location of the slides on the flanks of the Vema Dome is interpreted as that they were in part initiated due to the increased dip on the flanks of the dome cause by differential uplift during the Late Miocene (6–8 Ma). These slides have three particularly unusual characteristics in comparison to other submarine slides: a relatively low ratio of length to thickness, are dominated by regular spaced folds and thrusts, and short translational distances. We attribute these characteristics to deep detachments that resulted from the inherent ability of biosiliceous sediments to maintain a cohesive framework and resist failure during early burial (burial depths < 75 m).

► Four submarine slides are identified on the flanks of the Vema Dome, Vøring Basin.
► Each covers an area of ~30 km2 and is several hundred metres thick.
► They are dominated by regular-wavelength arcuate ridges above internal thrust faults.
► The slides have a relatively low ratio of length to thickness.
► The cohesive framework of the biosiliceous sediments during early burial is key.