HR: 1330h
AN: PP42A-0858    [PDF]
TI: A Geochemical/Mineralogical Record of Climate Variability in the Westernmost Mediterranean During Last 16,000 Years
AU: * Jimenez-Espejo, F J
EM: fjjspejo
AF: Andaluz de Ciencias de la Tierra (CSIC-UGR), Campus Fuentenueva S/N.Facultad de Ciencias, Granada, 18002 Spain
AU: Martinez-Ruiz, F
EM: fmruiz@ugr.es
AF: Andaluz de Ciencias de la Tierra (CSIC-UGR), Campus Fuentenueva S/N.Facultad de Ciencias, Granada, 18002 Spain
AU: Gonzalez-Donoso, J M
EM: jmgd@uma.es
AF: Universidad de Malaga, Departamento de Geologia. Campus de Teatinos S/N, Malaga, 29071 Spain
AU: Linares, D
EM: jmgd@uma.es
AF: Universidad de Malaga, Departamento de Geologia. Campus de Teatinos S/N, Malaga, 29071 Spain
AU: Bernasconi, S M
EM: stefano@erdw.ethz.ch
AF: Geologisches Institut, ETH-Zentrum, Sonneggstrasse 5, Zurich, 8092 Switzerland
AB: The Alboran Sea basin, in the westernmost Mediterranean, represents an exceptional natural laboratory to record climatic changes due to very high sedimentation rates. A high resolution analysis from a gravity core spanning the last 16,000 yr is presented here. This core was recovered during the TTR 9-Leg 3 in 1999 (35$\deg$ 57.814 N, 03$\deg$ 30.655m W; water depth: 1526 m). Sediments are mostly composed of calcite (40-60%), clay minerals (20-35%), quartz (10-20%) and trace amounts of dolomite and feldspar ($<$ 10%). Clay mineral assemblages consist of illite (35-65%) smectite and I/S mixed-layers (20-60%) chlorite ($<$10%) and kaolinite($<$10%). Oxygen isotope composition and total organic carbon content (TOC) also present significant variations related to climate and/or oceanographic changes. The end of the Last Glacial Maximun (LGM) is characterized by an increase in TOC and a higher detrital input as indicated by increasing illite+chlorite content, suggesting enhanced productivity and supporting the increasing river outflow. The Younger Dryas (YD) is also characterized by dramatic changes in detrital input, mineral and geochemical composition (e.g., abrupt decrease in kaolinite content). After the YD a significant increase in TOC is observed. An opposite trend in kaolinite TC contents is reported along this record. A decrease in kaolinite derived from eolian input supports enhanced humidity periods with increasing runoff and nutrient supply leading to higher productivity. These fluctuations also correlate with those from $\delta^{18}$O values which suggest rapid changes in SSTs and oceanographic conditions. The $\delta^{18}$O profile reveals major climate changes since the LGM as well as cyclic and rapid changes specially significant during the last 5000 yr. Such fluctuations in isotope composition can be also correlated with other STT records obtained in the Alboran Sea basin.
DE: 1050 Marine geochemistry (4835, 4850)
DE: 3030 Micropaleontology
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting