Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 4 5 2008 10.5194/cpd-4-1219-2008 http://www.clim-past-discuss.net/4/1219/2008/ http://www.clim-past-discuss.net/4/1219/2008/cpd-4-1219-2008.html http://www.clim-past-discuss.net/4/1219/2008/cpd-4-1219-2008.pdf 1219 1235 2008-10-27 The 8.2 ka cooling event related to extensive melting of the Greenland Ice Sheet H. Ebbesen heb@geus.dk A. Kuijpers M. Moros J. Lloyd M.-S. Seidenkrantz S. Troelstra Geological Survey of Denmark and Greenland, Denmark Institute for Baltic Sea Research, Warnemünde, Germany Department of Geography, University of Durham, UK Institute of Geology, Aarhus University, Denmark Department of Paleoclimatology and Geomorphology, Vrije Universiteit, The Netherlands The North Atlantic cooling event at 8200 calibrated (cal) yr BP has been attributed to effects of an extensive freshwater discharge from the Hudson Strait (Barber et al., 1999; Leverington et al., 2002). Here we present sedimentary records from 5 cores collected from the Greenland shelf. These document high magnetic susceptibility (MS) values related to massive silt deposition, which is ascribed to large-scale melt water outflow from the Greenland Ice Sheet (GIS) spanning the centuries before 8200 cal yr BP and ending after 8000 cal yr BP. XRF trace element composition and foraminiferal fauna's provide additional evidence for excessive melt-water production, which can be related to early Holocene warming of the circum-Arctic region including Greenland. Planktonic foraminiferal fauna data from the southern Davis Strait indicate the widespread presence of negative salinity anomalies reaching far offshore Greenland. Significant freshening of surface waters around Greenland prior to 8200 cal yr BP must have led to a slowdown of the deep-water formation which thus implies that significant melting of the GIS should be taken into account when discussing driving mechanisms behind the 8200 cal yr BP cooling event. Barber, D. C., Dyke, A., Hillaire-Marcel, C., Jennings, A. E., Andrews, J. T., Kerwin, M. W., Bilodeau, G., McNeely, R., Southon, J., Morehead, M. D., and Gagnon, J. M.: Forcing of the cold event 8200 years ago by catastrophic drainage of laurentide lakes, Nature, 400, 344–348, 1999. Leverington, D. W., Mann, J. D., Teller, J. T.: Changes in the bathymetry and volume of glacial Lake Agassiz between 9200 and 7700 $^14$C yr BP, Quat. Res., 57, 244–252, 2002. Steffen, K., Nghiem, S. V., Huff, R., and Neumann, G.: The melt anomaly of 2002 on the Greenland Ice Sheet from active and passive microwave satellite observations, Geophys. Res. Lett., 31(20), L20402, doi:10.1029/2004GL020444, 2004. Rignot, E. and Kanagaratnam, P.: Changes in the Velocity Structure of the Greenland Ice Sheet, Science, 311(5763), 986–990, 2006. Arctic Climate Impact Assessment (ACIA): Issued by the Fourth Arctic Council Ministrerial Meeting, Reykjavik, 2004. Overpeck, J., Hughen, K., Hardy, D., Bradley, R., Case, R., Douglas, M., Finney, B., Gajevski, K., Jacoby, G., Jennings, A., Lamoureux, S., Lasca, A., MacDonald, G., Moore, J., Retelle, M., Smith, S., Wolfe, A., and Zielinski, G.: Arctic environmental change of the last four centuries, Science, 278, 1251–1256, 1997. Johnsen, S. J., Clausen, H. B., Dansgaard, W., Fuhrer, K., Gundestrup, N., Hammer, C. U., Iversen, P., Jouzel, J., Stauffer, B., and Steffensen, J. P.: Irregular glacial interstadials recorded in a new Greenland ice core, Nature, 359, 311–313, 1992. Klitgaard-Kristensen, D., Sejrup, H. P., Haflidason, H., Johnsen, S., and Spurk, M.: A regional 8200 cal. yr BP cooling event in northwest Europe, induced by final stages of the Laurentide ice-sheet deglaciation?, J. Quat. Sci., 13, 165–169, 1998. Risebrobakken, B., Jansen, E., Andersson, C., Mjelde, E., and Hevrøy, K.: A high-resolution study of Holocene paleoclimatic and paleoceanographic changes in the Nordic Seas, Paleoceanography, 18(1), 1–14, 2003. Rohling, E. J. and Pälike, H.: Centennial-scale climate cooling with a sudden cold event around 8,200 years ago, Nature, 434, 975–979, 2005. Cuny, J., Rhines, P. B., and Kwok, R.: Davis Strait volume, freshwater and heat fluxes, Deep-Sea Res. I, 52, 519–542, 2005. Tang, C. C. L., Ross, C. K., Yao, T., Petrie, B., DeTracey, B. M., and Dunlap, E.: The circulation, water masses and sea- ice of Baffin Bay, Prog. Oceanogr., 63, 183–228, 2004. Seidenkrantz, M.-S., Aagaard-Sørensen, S., Sulsbrück, H., Kuijpers, A., Jensen, K. G., and Kunzendorf, H.: Hydrography and climate of the last 4400 years in a SW Greenland fjord: implications for Labradors Sea Palaeoceanography, The Holocene, 17(3), 387–401, 2007. Stuiver, M., Reimer, P. J., and Reimer, R.: Calib radiocarbon calibration, Execute version 5.0.2 html, available online: calib.qub.ac.uk/calib/, 2006. Reimer, P.: Marine Reservoir Correction Database, Queens University Belfast, available online: intcal.qub.ac.uk/marine/, 2005. Steinsund, P. I., Polyak, L., Hald, M., Mikhailov, V., and Korsun, S.: Distribution of calcareous benthic foraminifera in recent sediments of the Barents and Kara Seas, J. Foraminiferal Res., 61–102, 1994. Korsun, S. and Hald, M.: Seasonal dynamics of benthic foraminifera in a glacially fed fjord of Svaldbard, European arctic, J. Foraminiferal Res., 30(4), 251–271, 2000. Rytter, F., Knudsen, K. L., Seidenkrantz, M.-S., and Eiríksson, J.: Modern distribution of benthic foraminifera on the North Icelandic shelf and slope, J. Foraminiferal Res., 32, 217–244, 2002. Ren, J., Jiang, H., Seidenkrantz, M.-S., and Kuijpers, A.: A diatom-based reconstructon of Early Holocene hydrographic and climatic change in a southwest Greenland fjord, Mar. Micropaleonthol., revised, 2008. Kuijpers, A., Abrahamsen, N., Hoffmann, G., Hühnerbach, V., Konradi, P., Kunzendorf, H., Mikkelsen, N., Thiede, J., and Weinrebe, W.: Climate change and the Viking-age fjord environment of the Eastern Settlement, South Greenland, Geology of Greenland Survey Bulletin, 183, 61–67, 1999. Lassen, S. J., Kuijpers, A., Kunzendorf, H., Hoffmann-Wieck, G., Mikkelsen, N., and Konradi, P.: Late-Holocene Atlantic bottom-water variability in Igaliku Fjord, South Greenland, reconstructed from foraminifera faunas, The Holocene, 14(2), 165–171, 2004. Kuijpers, A., Troelstra, S. R., Prins, M. A., Linthout, K., Akhmetzhanov, A., Bouryak, S., Bachmann, M. F., Lassen, S., Rasmussen, T., and Jensen, J. B.: Late Quaternary sedimentary processes and ocean circulation changes at the Southeast Greenland margin, Mar. Geol., 195, 109–129, 2003. Mudie, P. T., Rochon, A., Prins, M. A., Soenarjo, D., Troelstra, S. R., Levac, E., Scott, D. B., Roncaglia, L., and Kuijpers, A.: Late Pleistocene-Holocene Marine Geology of Nares Strait Region, Palaeoceanography from Foraminifera and Dinoflagellate Cysts, Sedimentology and Stable Istopes, Polarforschung, 74(1–3), 169–183, 2004, appeared 2006. Ebbesen, H., Hald, M., and Eplet, T.-H.: Lateglacial and Early Holocene climatic oscillation on the western Svalbard margin, European Arctic, Quat. Sci. Rev., 26, 1999–2011, 2007. Sarnthein, M., Van Kreveld, S., Erlenkeuser, H., Grootes, P. M., Kucera, M., Pflaumann, U., and Schulz, M.: Centennial-to-millennial-scale periodicities of Holocene climate and sediment injections off the western Barents shelf, 75° N, Boreas, 32, 448–461, 2003. Keigwin, L. D., Sachs, J. P., Rosenthal, Y., and Boyle, E. A.: The 8200 year BP event in the slope water system, western subpolar North Atlantic, Paleoceanography, 20, PA2003, doi:10.1029/2004PA001074, 2005. Kaufmann, D. S., Ager, T. A., Anderson, N. J., Anderson, P. M., Andrews, J. T., Bartlein, P. J., Brubaker, L. B., Coats, L. L., Cwynar, L. C., Duvall, M. L., Dyke, A. S., Edwards, M. E., Eisner, W. R., Gajewski, K., Geirsdóttir, A., Hu, F., S., Jennings, A. E., Kaplan, M. R., Kerwin, M. W., Lozhkin, A. V., MacDonald, G. M., Miller, G. H., Mock, C. J., Oswald, W. W., Otto-Bliesner, B. L., Porinchu, D. F., Rühland, K., Smol, J. P., Steig, E. J., and Wolfe, B. B.: Holocene thermal maximum in the western Arctic (0–180° W), Quate. Sci. Rev., 23, 529–560, 2004. Hillaire-Marcel, C., de Vernal, A., Bilodeau, G., and Weaver, A. J.: Absence of deep-water formation in the Labrador Sea during the last interglacial period, Nature, 410, 1073–1077, 2001.