HR: 1340h
AN: PP23A-1401    [Abstracts]
TI: Response of East African climate to orbital forcing during two glacial-interglacial cycles: The Lake Naivasha Coring Project
AU: * Bergner, A G
EM: bergner@geo.uni-potsdam.de
AF: Universitaet Potsdam, Institut fuer Geowissenschaften, Postfach 601553, Potsdam, D-14415 Germany
AU: Trauth, M H
EM: trauth@geo.uni-potsdam.de
AF: Universitaet Potsdam, Institut fuer Geowissenschaften, Postfach 601553, Potsdam, D-14415 Germany
AU: Deino, A
EM: al@bgc.org
AF: Berkeley Geochronology Center, 245 Ridge Road, Berkeley, 94709 United States
AU: Mingram, J
EM: ojemi@gfz-potsdam.de
AF: Geoforschungszentrum Potsdam, Telegrafenberg, Potsdam, D-14473 Germany
AU: Strecker, M R
EM: strecker@geo.uni-potsdam.de
AF: Universitaet Potsdam, Institut fuer Geowissenschaften, Postfach 601553, Potsdam, D-14415 Germany
AB: High-quality chronologies of late Pleistocene tropical climate have become increasingly important in discussions concerning tropical forcing of deglaciation, i.e., the transition from a glacial to an interglacial. The key argument of this hypothesis is that tropical climate leads high-latitude ice regression by several thousand years. A tropical forcing of deglaciation would also help to explain why ice ages occur in both hemispheres simultaneously, although the changes in solar irradiance from orbital variations have opposite effects in the two hemispheres. The Central Kenya Rift provides a unique opportunity to study continuous records of tropical climate changes during the last two glacial-interglacial cycles (approximately 150 kyr) through sedimentological and paleoecological changes documented in lake sediments. We have assessed the amplitude and timing of East African climate change during Termination II from Ar/Ar-dated onshore lacustrine deposits in the Lake Niavasha basin. Our results show that local precipitation increased by up to 30% already between 145-135 kyr BP. Now we track similar environmental changes at Termination I using two 40-kyr-old sediment cores from Lakes Naivasha and Nakuru. The new sediment records are expected to prove the hypothesis that hydrological changes in East Africa follow early warming of the tropics due to strengthen of local solar radiation.
DE: 9305 Africa
DE: 3344 Paleoclimatology
DE: 3309 Climatology (1620)
DE: 1719 Hydrology
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting