HR: 1340h
AN: PP33B-1567    [Abstracts]
TI: Advection of Atlantic Water to the Western and Northern Svalbard Shelves Through the Last 17.5 ka cal yr BP
AU: * Slubowska, M A
EM: martas@unis.no
AF: Department of Arctic Geology, The University Centre in Svalbard, Longyearbyen, 9171 Norway
AU: * Slubowska, M A
EM: martas@unis.no
AF: Department of Geology, University of Tromso, Tromso, 9037 Norway
AU: Rasmussen, T L
EM: Tine.Rasmussen@ig.uit.no
AF: Department of Geology, University of Tromso, Tromso, 9037 Norway
AU: Koc, N
EM: nalan@npolar.no
AF: Norwegian Polar Institute, Polar Environmental Centre, Tromso, 9296 Norway
AU: Kristensen, D K
EM: dorthe@npolar.no
AF: Norwegian Polar Institute, Polar Environmental Centre, Tromso, 9296 Norway
AU: Nilsen, F
EM: frankn@unis.no
AF: Department of Arctic Geology, The University Centre in Svalbard, Longyearbyen, 9171 Norway
AU: Solheim, A
EM: as@ngi.no
AF: Department of Arctic Geology, The University Centre in Svalbard, Longyearbyen, 9171 Norway
AU: Solheim, A
EM: as@ngi.no
AF: International Centre for Geohazards, Norwegian Geotechnical Institute, Ulleval Stadion, Oslo, 0806 Norway
AB: We have studied the distribution of benthic foraminifera species together with planktonic and benthic foraminifera abundances, stable oxygen isotopes and lithology in two cores: JM02-440 from the western (77° 22' N, 12° 48' E, 240 m water depth) and NP94-51 from the northern (80° 21' N and 16 ° 17' E, 400 m water depth) shelf of Svalbard. The purpose of the study was to reconstruct the changes in flow and character of the relatively warm Atlantic Water through the last 17.5 ka cal yr BP. The results from these two sites were compared with previously published records from the eastern Nordic Seas in order to follow the history of the advection of Atlantic Water as it moved northwards along the Norwegian coast and into the Arctic Ocean. Our results indicate that synchronous oceanographic changes occurred at the western and northern Svalbard shelves. The benthic foraminifera and oxygen isotope records indicate almost continuous presence of the Atlantic Water at the shelf areas since the deglaciation. The Bolling-Allerod period stands out as the warmest period in our records with the highest bottom waters temperatures indicating strong inflow of Atlantic Water. However, the warm Atlantic Water was isolated below cold and probably sea ice covered surface waters in contrast to the surface waters along the Norwegian coast, which experienced enhanced temperatures. During the Younger Dryas a freshening of the bottom waters occurred and the Polar Front was located in a proximal position to both sites. The strong inflow of saline, but chilled Atlantic Water happened during the Early Holocene. A distinct cooling and freshening of the bottom water masses occurred during the Mid- and Late Holocene, and was accompanied by glacier re-advances leading to the present-day conditions. During the last millennium, the inflow of Atlantic Water appears to increase, but the conditions turned unstable. The development of the paleoceanographic conditions at the western and northern Svalbard margins correlate closely to the SST variations in the Nordic Seas region since the deglaciation, and confirms that the Svalbard area is highly sensitive to the fluctuations in the inflow of Atlantic Water. The Early Holocene warming observed in the surface waters of the Nordic Seas correlate with the strong advection of Atlantic Water to the bottom waters of the western and northern Svalbard shelves and the Arctic Ocean. The warming was not just an effect of increased solar insolation, but was also due to the enhanced flux of Atlantic Water driven by the increased wind force and/or the thermohaline circulation.
DE: 4207 Arctic and Antarctic oceanography (9310, 9315)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4926 Glacial
DE: 4936 Interglacial
DE: 4962 Thermohaline
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005