SEDIMENTS, SEDIMENTATION-RATES, AND ENVIRONMENTS, SOUTHEAST BAFFIN SHELF AND NORTHWEST LABRADOR SEA, 8-26 KA

Ten C-14-dated cores are described from the Labrador Sea, continental slope, and Hatton and Resolution basins on the southeast Baffin Shelf. Based on sharply defined detrital carbonate layers in the Labrador Se a cores, we propose that the Laurentide Ice Sheet reached the shelf br eak at both 20 and 15 C-14 ka (24.3 and 18.2 sidereal ka) and contribu ted significant sediment to the northwest Labrador Sea both times; the flux was +/- 720 kg/(m2 . ka) during these periods of maximum ice ext ent. The Laurentide Ice Sheet retreated from its 15 ka position at the shelf break to the inner shelf between 14 and 12 C-14 ka. Ice-proxima l conditions, recognized by relatively light deltaO-18 on near-surface planktonic foraminifera, high detrital carbonate, and benthic foramin iferal faunas (dominated by Elphidium excavatum forma clavata; Cassidu lina reniforme), prevailed until at least 10 C-14 ka. The ice readvanc ed toward Resolution Basin and across part of Hatton Basin at 11 C-14 ka. Accelerator mass spectrometry dates on core tops indicate that dep osition on the shelf virtually ceased by 7 ka and was very low in the northwest Labrador Sea throughout the Holocene. Downcore accelerator m ass spectrometry dates indicate that during deglaciation, the loci of depocentres shifted in response to changes in the position of the ice margin. On the southeast Baffin Island shelf net sediment fluxes at th e sea floor reached values of over 3000 kg/(m2 . ka) between 12 and 10 C-14 ka, of which nearly half was detrital carbonate, principally cal cite.