The 8.2 ka event from Greenland ice cores |
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| Institution: | 1. British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3-0ET, UK;2. Department of Geophysics, The Niles Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, Juliane Maries Vej. 30, DK-2100 Copenhagen, Denmark;3. NERC Isotope Geosciences Laboratory, British Geological Survey, Kingsley Dunham Center, Keyworth, Nottingham NG12-5GG, UK;4. Institute of Arctic and Alpine Research, Boulder, Colorado, USA;5. Department of geological Sciences and Environmental Studies Program, University of Colorado, Boulder, Colorado 80309, USA;1. INSTAAR, and Dept. of Geological Sciences, Univ. of Colorado, USA;2. Centre for Past Climate Studies, Department of Geoscience and Arctic Research Centre, Aarhus University, Aarhus, Denmark;3. Akvaplan-niva AS, Fram Centre, N-9296 Tromsø, Norway;4. Department of Earth Science, University of Bergen, Bergen, Norway;1. Department of Geology, University of Georgia, Athens, GA, 30602-2501, USA;2. University of Leeds, School of Earth and Environment, Leeds, LS2 9JT, UK;3. Ice Dynamics and Paleoclimate, British Antarctic Survey, Cambridge, CB3 0ET, UK;4. Institute of Global Environmental Change, Xi''an Jiaotong University, Xi''an, Shaanxi, 710049, PR China;5. Department of Earth Sciences, University of Minnesota, Minneapolis, MN, 55455, USA;6. Department of Geography, University of Georgia, Athens, GA, 30602-2502, USA;7. Mention Sciences de la Terre et de l’Environnement, Domaine Sciences et Technologie, Université d’Antananarivo, Madagascar;1. University of Reading, Department of Archaeology, United Kingdom;2. University of Reading, Centre for Past Climate Change, United Kingdom;1. Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberg, Senckenberganlage 25, 60325 Frankfurt am Main, Germany;2. Institute for Inorganic and Analytic Chemistry, University Jena, Humboldstraße 8, 97743 Jena, Germany;3. Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745 Jena, Germany;4. Paleoenvironmental Dynamics Group, Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany;5. Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt am Main, Germany;1. Department of Geology, University of Georgia, Athens, GA 30602, USA;2. Department of Geography, Western Illinois University, 1 University Circle, Macomb, IL 61455, USA;3. Department of Geography, University of Georgia, Athens, GA 30602, USA;4. Gobabeb Research and Training Centre, P.O. Box 953, Walvis Bay, Namibia;5. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA;6. College of Global Environmental Change, Xi''an Jiaotong University, Xi''an, Shaanxi 710049, China;7. Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA |
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| Abstract: | We present a collection of high-resolution chemistry and stable isotope records from the plateau of the Greenland ice cap during the cold event 8200 yr ago. Using a composite of four records, the cold event is observed as a 160.5 yr period during which decadal-mean isotopic values were below average, within which there is a central event of 69 yr during which values were consistently more than one standard deviation below the average for the preceding period. Four cores in north, south, and central Greenland show differences at decadal and shorter timescales; it is not yet clear if this represents significant spatial differences in response. The results show clear evidence for colder temperatures and a decrease in snow-accumulation rate. However, the changes in chemical concentrations for the ions looked at here are small, suggesting only minor changes in atmospheric circulation for this event. Apart from the decrease in methane concentration, Greenland ice cores give only weak evidence for effects outside the North Atlantic region. |
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