Variations in Atlantic surface ocean paleoceanography, 50ø-80øN: A time-slice record of the last 30,000 years

• Published in: Paleoceanography
• Main Authors: Sarnthein, Michael, Jansen, Eystein, Weinelt, Mara, Arnold, Maurice, Duplessy, Jean Claude, Erlenkeuser, Helmut, Flatøy, Astrid, Johannessen, Gro, Johannessen, Truls, Jung, Simon, Koc, Nalan, Labeyrie, Laurent, Maslin, Mark, Pflaumann, Uwe, Schulz, Hartmut, Samthein, Michael, Duplessy, Jean, Flat0y, Astrid
• Other Authors: Kiel University, Geological Institute Bergen, University of Bergen (UiB), Centre des Faibles Radioactivités, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences Cambridge, UK, University of Cambridge UK (CAM)-University of Cambridge UK (CAM), Institut für Geologie Hannover, Leibniz Universität Hannover=Leibniz University Hannover
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1995
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Norway; Ice Sheet; Iceland; Nordic Seas; Northern Norway; Planktonic foraminifera; Sea ice
• Online Access: https://hal.science/hal-03609307; https://hal.science/hal-03609307/document; https://hal.science/hal-03609307/file/Paleoceanography%20-%20December%201995%20-%20Sarnthein%20-%20Variations%20in%20Atlantic%20surface%20ocean%20paleoceanography%2050%20%E2%80%9080%20N%20A.pdf; https://doi.org/10.1029/95PA01453

International audience Eight time slices of surface-water paleoceanography were reconstructed from stable isotope and paleotemperature data to evaluate late Quaternary changes in density, current directions, and sea-ice cover in the Nordic Seas and NE Atlantic. We used isotopic records from 110 deep-sea cores, 20 of which are accelerator mass spectrometry (AMS)-14C dated and 30 of which have high (>8 cm/kyr) sedimentation rates, enabling a resolution of about 120 years. Paleotemperature estimates are based on species counts of planktonic foraminifera in 18 cores. The •5180 and •513C distributions depict three main modes of surface circulation: (1) The Holocene-style interglacial mode which largely persisted over the last 12.8 •4C ka, and probably during large parts of stage 3. (2) The peak glacial mode showing a cyclonic gyre in the, at least, seasonally ice-free Nordic Seas and a meltwater lens west of Ireland. Based on geostrophic forcing, it possibly turned clockwise, blocked the S-N flow across the eastern Iceland-Shetland ridge, and enhanced the Irminger current around west Iceland. It remains unclear whether surface-water density was sufficient for deepwater formation west of Norway. (3) A meltwater regime culminating during early glacial Termination I, when a great meltwater lens off northern Norway probably induced a clockwise circulation reaching south up to Faeroe, the northward inflow of Irminger Current water dominated the Icelandic Sea, and deepwater convection was stopped. In contrast to circulation modes two and three, the Holocene-style circulation mode appears most stable, even unaffected by major meltwater pools originating from the Scandinavian ice sheet, such as during •80 event 3.1 and the B611ing. Meltwater phases markedly influenced the European continental climate by suppressing the "heat pump" of the Atlantic salinity conveyor belt. During the peak glacial, melting icebergs blocked the eastward advection of warm surface water toward Great Britain, thus accelerating buildup of the ...