HR: 0800h
AN: PP31A-0899    [Abstracts]
TI: Meltwater Outflow and Laminated Plume Deposition in the Southern Norwegian Sea Preceding Heinrich Event 1.
AU: * Lekens, W A
EM: wim.lekens@geo.uib.no
AF: Department of Earth Science, University of Bergen, Allegaten 41, Bergen, 5007 Norway
AU: Sejrup, H P
EM: sejrup@geo.uib.no
AF: Department of Earth Science, University of Bergen, Allegaten 41, Bergen, 5007 Norway
AU: Haflidason, H
EM: haflidi.haflidason@geo.uib.no
AF: Department of Earth Science, University of Bergen, Allegaten 41, Bergen, 5007 Norway
AU: Ostvik Petersen, G
EM: gunn.moe@student.uib.no
AF: Department of Earth Science, University of Bergen, Allegaten 41, Bergen, 5007 Norway
AU: Knor, G
EM: gregor.knorr@dkrz.de
AF: Institute for meteorology, University of Hamburg, Bundesstrasse 55, Hamburg, 20146 Germany
AB: Rapidly deposited laminated sediments dated between 18 and 22 ka BP have been observed at several locations in the Northern North Sea and the Southern Norwegian Sea. Sedimentation rates range from 20 cm/ka up to 2000 cm/ka, compared to a normal background sedimentation rate in the area of 5 to 10 cm/ka. Detailed sedimentological work revealed that the laminations are possibly marine annual varves, indicated by cyclic changes in the number of planktonic foraminifera and lithology. The deposits have been identified as the product of a large suspension plume and are associated with lighter d18O values compared to the region, indicating meltwater inflow. The laminated deposits identified along the upper continental margin off southern Norway occurred mainly during the early deglaciation at 18.6 ka BP and are believed to originate from the presence and fast retreat of the Norwegian Channel Ice Stream. Simultaneously, increased fluxes were observed on the Barra Fan, the North Sea Fan, the Lofoten contourite and the Svalb‘rd margin, preceding increased fluxes on the Greenland margin and the Labrador Sea, associated with Heinrich event 1. Between 21 and 18 ka BP planktonic foraminifera indicate warm water inflow to the area. This, possibly together with an increase in sea level, probably triggered the melting of the low latitude parts of the Fennoscandian ice sheet, leading to a massive output of material to the continental slope. A similar response of the Laurentide ice sheet occurred 500 to 1000 yrs later during Heinrich event 1.
DE: 4267 Paleoceanography
DE: 3022 Marine sediments--processes and transport
DE: 3030 Micropaleontology
DE: 1035 Geochronology
DE: 1040 Isotopic composition/chemistry
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting