Description: Surface sediment samples for analysis of modern foraminiferal assemblages were collected from 32 sites on the western and northern Iceland shelf during cruise B997 of the Icelandic ship Bjarni Saemundsson. The purpose of the study is to provide a basis for interpreting the variations in foraminiferal content in late glacial through Holocene sediments from cores at the same sites. Cluster analysis and principal components analysis of the benthic foraminiferal data and associated modern environmental parameters including hydrography, water depth, and sediment characteristics show that large progressive changes in the foraminiferal assemblages coincide with changes in the dominant oceanic surface currents and water masses around Iceland. The western areas of the shelf are overlain by relatively warm and saline Atlantic Water of the Irminger Current. The western shelf fauna is dominated by Cassidulina laevigata and other boreal species, whereas the planktic fauna is dominated by dextrally coiling Neogloboquadrina pachyderma. In Djúpáll, off the Northwest Peninsula, and in the shallow nearshore sites on the northern shelf, the boreal elements of the fauna diminish and arctic species become more important. However, the dominant species in these areas are Cibicides lobatulus and Astrononion gallowayi, attesting to winnowing of the shallow shelf areas by currents. In Isafjardardjúp, the large fjord indenting the Northwest Peninsula, Cassidulina reniforme and Elphidium excavatum dominate the fauna as a result of cooler waters and more variable salinity conditions. A very large faunal shift is registered in the deep basins of the northern shelf. This faunal shift coincides with large changes in salinity and temperature stratification of the water column, reflecting the presence of the East Iceland Current. The fauna in the deep basins on the northern shelf are dominated by C. neoteretis, an indicator of modified Atlantic Water, and infaunal species that reflect organic fluxes to the seabed: Nonionellina labradorica and Melonis barleeanus, and the arctic species Islandiella norcrossi and I. helenae.

Description: In the North Atlantic we define H-0 as a Heinrich-like event which occurred during the Younger Dryas chron. On the SE Baffin shelf prior to 11 ka, surface water productivity was reasonably high, as measured by the numbers of diatom and planktic foraminifera per gram, but an abrupt increase in detrital carbonate (DC-0 event) (from approximately 15% up to 50% carbonate by weight) occurred at 11 ± 14C ka and continued to circa 10 ka. These deposits, 2–6 m thick, are dominated by detrital calcite and silt- and clay-sized sediments. During this event (DC-0/H-0), ice extended onto the inner shelf but did not reach the shelf break and probably originated from a center over Labrador-Ungava. As a consequence, the pattern of ice-rafted debris and sediment provenance shown by H-O in the North Atlantic is different from that during H-1 (14.5 ka) or H-2 (20 ka) when the ice sheet extended along the axis of Hudson Strait and may have reached the shelf break; for example, there is no concrete evidence for DC-O is cores on the floor of the Labrador Sea due east of Hudson Strait (HU75-55,-56), but H-O has been noted in cores off Newfoundland and west of Ireland. A coeval carbonate event to DC-0, but this one dominated by dolomite, occurs in HU82-SU5 on the west side of Davis Strait with a source either from northern Baffin Bay or Cumberland Sound. Although other sources for North Atlantic detrital carbonate cannot be totally excluded, our evidence suggests that H-0 represents the expression of glaciological instability of the Laurentide Ice Sheet within the general region of Hudson Strait and probably to the north (Cumberland Sound and northernmost Baffin Bay). There is one younger DC event, dated circa 8.4 ka, present in sediments along the Labrador margin and in Hudson Strait, which represents the final collapse of the ice sheet within Hudson Strait and Hudson Bay.