HR: 0800h
AN: PP21A-1545    [Abstracts]
TI: An Abrupt Change in the African Monsoon at the end of the Younger Dryas?
AU: * Talbot, M R
EM: michael.talbot@geo.uib.no
AF: University of Bergen, Department of Earth Sciences, Allégt. 41, Bergen, N-5007 Norway
AU: Filippi, M L
EM: filippi@mtsn.tn.it
AF: Museo Tridentino Scienze Naturali, via Calepina 14, Trento, 38100 Italy
AU: Jensen, N B
EM: Niels.Jensen@rf.no
AF: Rogalandsforskning, Rogaland Research, Thormoelens gt. 55, Bergen, N-5008 Norway
AU: Tiercelin, J
EM: jjtierc@univ-brest.fr
AF: UMR CNRS 6538 "Domaines Océaniques", Inst. Universitaire Européen de la Mer, Place Nicolas Coopernic, Plouzané, 29280 France
AB: A variety of proxy palaeoclimatic records from tropical Africa and the adjacent oceans suggest that a climatic event equivalent to the Younger Dryas (YD) also affected this region. To date however, little attention has been directed towards the end of the YD in Africa, even though it has been identified as a period of particularly rapid and profound climatic change in the circum-North Atlantic region. High-resolution studies of variations in the elemental and stable carbon- and nitrogen-isotope composition of organic matter in cores from Lakes Malawi, Tanganyika and Bosumtwi (tropical Africa) indicate an abrupt change in the wind-driven circulation of these lakes that, within the limits of available chronologies, was contemporaneous with the end of the YD in the northern hemisphere. The change was apparently coincident with the transition to humid conditions in the central Sahara, with shifts in surface winds recorded in cores from off the coasts of East and West Africa, and possibly also with the onset of the last phase of ice accumulation on Mt. Kilimanjaro. Together, the evidence suggests an abrupt northward translation of the African monsoon system at ca. 11.5 +/- 0.3 cal. ka BP.
DE: 0746 Lakes (9345)
DE: 4870 Stable isotopes (0454, 1041)
DE: 4950 Paleoecology
DE: 9305 Africa
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005