Site U1605

Site U1605 (proposed Site MB-31A) was cored at 73°33.6421′N, 62°09.0687′W at 529 meters below sea level (mbsl) on the outermost part of the northwest Greenland shelf margin into Baffin Bay (Figure F1). Constrained by high-quality seismic data, the main objective was to recover potential marine intervals within packages of flat-lying, semicontinuous reflections developed between strong reflections that are interpreted as glacial unconformities within the topset strata succession of the Melville Bugt Trough Mouth Fan (Figure F2) (Knutz et al., 2019; Newton et al., 2021). Site U1605 captures Seismic Units 7–10 with a target depth just below Seismic Horizon 6, corresponding to 282 meters below seafloor (mbsf; based on an average P-wave velocity of 2200 m/s). The sequence is considered to extend to Early Pleistocene age and thus overlaps seismic-stratigraphically with deepwater Sites U1603 and U1604. The primary lithology was assumed to be compacted diamicton with intervals of sand and pebbly mud and possibly marine to glaciomarine deposits (Figure F3). As such, low but variable recoveries were expected at Site U1605.