HR: 16:45h
AN: PP44A-04    [Abstracts]
TI: Holocene Paleoceanography of the Southeast Greenland Shelf
AU: * Jennings, A E
EM: Anne.Jennings@colorado.edu
AF: INSTAAR and Dept. of Geological Sciences, University of Colorado, Boulder, CO 80309-0450 United States
AU: Andrews, J T
EM: John.T.Andrews@colorado.edu
AF: INSTAAR and Dept. of Geological Sciences, University of Colorado, Boulder, CO 80309-0450 United States
AU: Woody, K
PP44A-04 AF: INSTAAR and Dept. of Geological Sciences, University of Colorado, Boulder, CO 80309-0450 United States
AU: Anderson, D M
EM: David.m.anderson@NOAA.gov
AF: NOAA Paleoclimatology Branch, National Climate Data Center, Boulder, CO 80305-3328 United States
AU: Stoner, J S
PP44A-04 AF: COAS, Oregon State University, Corvallis, OR 97331-5503 United States
AB: Large shifts in paleoceanographic parameters including IRD, biogenic carbonate, stable isotopes, and benthic and planktic foraminiferal assemblages, are documented in two Calypso cores, MD99-2322 and MD99-2317, at century to multi-decadal timescales in Holocene sediments from the East Greenland shelf. The two cores are dated by radiocarbon dating, tephrostratigraphy and paleomagnetic secular variations. Cold, low salinity Polar Water that flows southward along the East Greenland shelf forms the surface water at both sites. Atlantic Water flows into the study area via both the Irminger and North Atlantic currents. The Irminger Current enters the Kangerlussuaq Trough, site of MD99-2322, south of the Denmark Strait, but is excluded from site MD99-2317, north of Denmark Strait. The bottom water at both sites derives from chilled Atlantic return water originating in the North Atlantic Current. Surface and bottom-water proxies are used to interpret past hydrographic conditions and to estimate paleotemperatures. In MD99-2322, a marked shift to high carbonate values c. 6500 cal yrs. BP is interpreted to reflect strong influence of the Irminger Current on the SE Greenland shelf in the middle Holocene. Although carbonate is very low throughout MD99-2317, extremely high percentages of Cassidulina neoteretis, a benthic foraminiferal species indicative of Atlantic Intermediate water, suggest that return Atlantic water also flooded the shelf north of the Denmark Strait beginning at 6500 cal yr BP. The IRD content of MD99-2322 shows frequent high spikes after 3300 cal yrs BP and the carbonate content declines after 2000 cal yr BP. To the north of Denmark Strait, MD99-2317 has an almost identical IRD record to MD99-2322, with a strong increase in IRD by 3500 cal yrs BP. As the IRD increases in MD99-2317, the percentage spikes in C. neoteretis diminish, and finally give way to an almost fully agglutinated fauna, indicating very cold conditions by 2800 cal yrs BP. These patterns reflect late Holocene cooling and/or thickening of the surface Polar Water and diminished influence of intermediate Atlantic Water on the SE Greenland shelf from both Irminger and North Atlantic sources in the late Holocene.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4944 Micropaleontology (0459, 3030)
DE: 4950 Paleoecology
DE: 4954 Sea surface temperature
DE: 9315 Arctic region (0718, 4207)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005