The Nyk Slide—morphology, progression, and age of a partly buried submarine slide offshore northern Norway

The late Weichselian Nyk Slide offshore northern Norway was investigated using high resolution seismic data, side-scan sonar imagery, and gravity cores. The mapable extent of the slide is ∼2200 km2, but parts of the slide were buried by glacigenic debris flows, and parts were removed by the younger Trænadjupet Slide. The exposed parts of the Nyk Slide exhibit extensional and, somewhat anomalously, compressional ridges in the upper slide area. We suggest that the two distinct morphologic zones originate from the same slide event. The compressional ridges are related to a particular large-scale funnel-shape morphology defined by the Vøring Plateau slope facing the continental slope, and were generated as the slide reached the foot of the Vøring Plateau slope. The extensional ridges were generated on the continental slope as sediments were transported downslope and subjected to stretching. Dating of the slide deposits indicate an age of ≥16.3 ka BP, synchronous with a time that the Fennoscandian Ice Sheet was fluctuating near the shelf edge. Nearby sediment cores and seismic reflection data reveal that the slide was both preceded and succeeded by episodes of deposition of glacigenic debris flows. The glide plane is located within the same unit of contouritic sediments as the glide plane of the Trænadjupet Slide, and the Nyk Slide, was probably triggered by loading and unloading of a fluctuating ice-front. The full extent of the slide is yet unknown, but the existing data suggest that the headwall continues upslope and follows the shelf edge outside the Trænadjupet Trough, implying that the Nyk Slide influenced an area substantially larger than the exposed slide deposits.