HR: 1340h
AN: PP43B-1280    [Abstracts]
TI: Organic Geochemical Evidence of Late Glacial-Holocene Climate Instability in the Aegean Sea: Teleconnections With North Atlantic Paleoclimate Variability
AU: Gogou, A
EM: agogou@aegean.gr
AF: Department of Marine Sciences, The University of the Aegean, Lesvos, 81100, Greece
AU: Gogou, A
EM: agogou@aegean.gr
AF: Marine Geology and Geochemistry Program, Department of Geological Sciences, The University of Michigan, Ann Arbor, MI 48109-1005, United States
AU: Katsouras, G
AF: Department of Marine Sciences, The University of the Aegean, Lesvos, 81100, Greece
AU: Katsouras, G
AF: Helenic Center for Marine Research, Institute of Oceanography, Anavyssos, 19013, Greece
AU: Emeis, K
AF: Institut fuer Biogeochemie und Meereschemie, Univeristaet Hamburg, Hamburg, 20146, Germany
AU: Bouloubassi, I
EM: ibou@ccr.jussieu.fr
AF: Laboratoire d'Oceanographie et du Climat, Universite Pierre et Marie Curie, Paris, Cedex o5, France
AU: Lykousis, V
AF: Department of Marine Sciences, The University of the Aegean, Lesvos, 81100, Greece
AU: Triantaphyllou, M
AF: Department of Historical Geology and Paleontology, University of Athens, Athens, 15784, Greece
AU: Arnaboldi, M V
EM: marna@umich.edu
AF: Marine Geology and Geochemistry Program, Department of Geological Sciences, The University of Michigan, Ann Arbor, MI 48109-1005, United States
AU: * Meyers, P A
EM: pameyers@umich.edu
AF: Marine Geology and Geochemistry Program, Department of Geological Sciences, The University of Michigan, Ann Arbor, MI 48109-1005, United States
AB: The Mediterranean Sea and its sediment record provide an ideal natural laboratory to study the history of climate changes and the responses of marine environments to these changes. Paleoceanographic and oceanographic studies highlight the Aegean Sea as an especially sensitive part of the Mediterranean Sea that is closely connected to global climatic variability. The hydrologic system of the Aegean Sea is complex, with a strong inflow of water from Black Sea and abundant rivers, and strong effects of atmospheric cooling on water mass formation and structure. Here we present a high-resolution multi-proxy study of three sediment cores collected from the north (MNB-3 and 152-SL) and central (NS-14) Aegean Sea. The cores consist of hemipelagic muds, including the sapropel layer S1 that was deposited between 9.8 to 6.4 kyr BP, along with the S1 interruption that occurred from 8.6 to 7.6 kyr BP. This study has identified important differences in multiple elemental, isotopic and molecular organic biogeochemical proxies that occurred during the late last Glacial to Holocene in response to local climate changes with the global climate variability. An important time marker and indicator for dramatic changes in the physical, chemical, and biological environment related to global climate variability is sapropel S1, a sediment layer rich in organic carbon. Our multi-proxy results identify several phases that can be related to distinct variations in paleoenvironmental conditions. Cold intervals recorded in the late last Glacial, the Younger Dryas, and during the S1 interruption show enhanced deep water convection and ventilation in response to surface water cooling probably driven by a strengthening of north winds over the NE Mediterranean Sea, related to a positive North Atlantic Oscillation phase. Warm intervals saw reduced thermohaline circulation/convection and increases in freshwater inputs related to increased intensity of the African monsoons. The warm phases caused the development of suboxic/ anoxic conditions, better organic matter preservation, and sapropel deposition during the Holocene. Interestingly, fluctuations in alkenone-SST and biogeochemical proxies within this sapropelic layer reveal that several distinct cooling events occurred during deposition of S1 that are concordant with North Atlantic Oscillations and that caused pulses of reventilation in the deep basins in the Aegean Sea.
DE: 1055 Organic and biogenic geochemistry
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 4802 Anoxic environments (0404, 1803, 4834, 4902)
DE: 4870 Stable isotopes (0454, 1041)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting