CORIBAR Ice dynamics and meltwater deposits: coring in the Kveithola Trough, NW Barents Sea - Cruise MSM30 - July 16 - August 15, 2013 - Tromsø (Norway) - Tromsø (Norway) (English)

The CORIBAR cruise aimed at drilling glacigenic sediments with the MARUM-owned seafloor drill rig MeBo in the Kveithola Trough, a palaeo-ice stream depositional system in the western Barents Sea. The main scientific objective was to reconstruct high- and deglacial icestream and sea-ice dynamics as a result of climatic variability. MeBo was used for the first time in polar regions to drill glacigenic deposits and to gain experience in drilling in high-latitude environments. Several MeBo deployments had to be stopped due to technical incidents and MeBo was finally deployed 9 times at 5 sites with a total cored length of 113 m (53 % recovery). Inside the trough, MeBo drilled with great recovery through the uppermost cohesive marine sediments. The underlying glacigenic deposits were highly compacted resulting in poor core recovery. Compacted sediments were also encountered inside a scar channel on the trough mouth fan. Marine plumite deposits underlying a sticky debrite, were soft and permeable which led to full flush-water drainage and, thus, an immovable stuck of the drilling case. Besides conventional sediment coring at 33 stations, intensive multibeam mapping extended the existing regional bathymetric map, illustrating the various morphological elements at the slope (shelf-edge gullies, young landslides, elongated slide scars) and on the shelf (currentleading channels, ice plough mark pattern, grounding-zone wedge boundaries). Dense-spaced PARASOUND profiling illustrated the subbottom architecture of the fan at the slope (plumites intercalated with glacigenic debrites and overlain by landslide bodies) and of the grounding-zone wedge succession (till successions overlain by a thick glacio-marine sequence), a drift system inside the trough (current-induced deposits of variable thickness, moats), and the surrounding glacigenic landscape (channels, several moraine generations, local depression fills).