EAST GREENLAND--DENMARK STRAIT--ICELAND: HEINRICH AND D-O EVENTS?

We have been working on a transect from East Greenland in the region of Kangerluqssuaq Trough (65°-68° N), across Denmark Strait, and onto the W and NW Iceland shelf (63°-67° N). Cruises in 1988, 1991, 1993, 1996, 1997, and 1999 were taken to obtain information on LGM ice extent, dates of deglaciation, and the paleoceanography of this vital gateway which links the Arctic and Nordic Seas with the subpolar North Atlantic Ocean. Studies both to the north and south, in the Blosseville and Irminger basins respectively, suggested rapid ice-sheet fluctuations at D-O frequencies and IRD intervals, coeval with Heinrich (H-) events; oscillations of the Iceland Ice Cap have been argued to be precursors of H-events. This presentation will focus on the results from cores: 1) HU93030-007 lies toward the base of the East Greenland slope and south of the DS sill; 2) JM96-1229 is from Blosseville Basin below the NW Iceland slope; 3) JM96-1226 lies south of the Denmark Strait sill mid-way beween the Iceland and Greenland slopes; and 4) B997-338 lies in Djupall, the trough which extends from the NW Iceland Peninsula (NWP) to the shelf break above the Blosseville Basin. These cores have “top” dates of between 10 and 14 ka and basal dates of between 26 and 34 ka, hence extend throughout the interval characterized by Heinrich events 0-3 (4?) and several D-O oscillations. B997-338 is the first core from the Iceland shelf which has a record > 14 ka. Its location indicates that during the LGM the ice extent on the NWP of Iceland extended a short distance beyond the coast. There are no signs of ice-proximal glacial deposition in JM96-1229 and IRD is limited, whereas at JM96-1225 (~V28-14) we recovered diamictons, and processes include a mixture of IRD, gravity flows, and current winnowing. Inferences about glacial history from ice distal deep-sea sources require verification in ice-proximal (shelf and slope) locations, and depositional processes must be evaluated.