HR: 1340h
AN: PP43A-0665    [Abstracts]
TI: Rapid Climate Changes In The Eastern Mediterranean Sea During The Holocene And Last Deglaciation Evidenced by Foraminiferal Mg/Ca
AU: * Weldeab, S
EM: sweldeab@geol.ucsb.edu
AF: Department of Geological Sciences and Marine Science Institute, University of California at Santa Barbara, Santa Barbara, CA 93106 United States
AU: Paetzold, J
EM: juergen.paetzold@uni-bremen.de
AF: Research Center Ocean Margins, University of Bremen, Klagenfurterstrasse, Bremen, 28357 Germany
AB: Here we present centennial-scale climate reconstruction from the Eastern Mediterranean Sea over the last 26,000 years. The AMS-dated core materials (GeoB7702-3) used for the climate reconstruction were retrieved within the immediate outflow of fresh water of the River Nile and at intermediate water depth (562m), thus providing insight into salinity, sea surface temperature (SST), and bottom water temperature (BWT) variations during the last 26 kyr. For SST and BWT estimates, Mg/Ca analyses were conducted on the shallow-dwelling planktonic foraminifera Globigerinoides ruber (white) and benthic foraminifera Cibicidoides pachydermus/Uvigerina perigrina, respectively. Long-term Mg/Ca SST and BWT variations indicate that pronounced deglaciation change occurred at around 14.5 kyr (BP), showing SST and BWT increase of 5°C and ~3°C, respectively. At time intervals (Heinrich events) that are characterized by an abrupt temperature drop in the northern high latitudes, our Mg/Ca SST record in the Eastern Mediterranean Sea reveal an increase of about 2°C during Heinrich events 2 and 1 as well as during the Younger Dryas. The Holocene also reveals several SST as well as BWT cooling intervals. The most pronounced SST and BWT coolings during the Holocene occurred during the intervals from 9.6 to 8.2 cal. kyr that is coincident with the deposition of sapropel 1 (S1) indicated by elevated Ba/Al ratios, and from 6.7 to 5.7 cal. kyr (BP). The fact that our records reveal warming during northern high-latitude deglacial coolings indicates limited influence of northern high latitudes on the Eastern Mediterranean Sea. Time interval (9.6 to 8.2 cal. kyr) of low SST and high fresh water input (indicated by low oxygen isotope composition of sea water) certainly had an effect on the balance of evaporation and fresh water input, and thus upon deep water formation favouring sapropel 1 formation in the Eastern Mediterranean Basin.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005