Global climate instability reflected by Eastern Mediterranean marine records during the late Holocene

Bettina Schilman, Miryam Bar-Matthews, Ahuva Almogi-Labin, Boaz Luz

Research output: Contribution to journalArticlepeer-review

186 Scopus citations

Abstract

Extremely high sediment accumulation rates in the southeastern (SE) Mediterranean off Israel make this region ideal for high-resolution paleoceanographic reconstructions. Two cores were examined and foraminiferal oxygen and carbon isotope composition as well as physical and geochemical properties of the sediments were used to reconstruct the climatic and environmental changes of the SE Mediterranean Basin during the late Holocene (3.6 ka). The δ18O values of Globigerinoides ruber suggest that the freshwater balance changed several times during this time interval. Humid phases took place between 3.5-3.0 ka BP and 1.7-1.0 ka BP. The later was accompanied by enhanced preservation of terrestrial organic matter within the sediment (ORS event). Relatively more arid conditions prevailed in this area between 3.0 and 1.7 ka BP. During the last millennia at ca. 0.8 and 0.27 ka two climatic events occurred which are probably correlative to both the Medieval Warm Period and the cooling global event known as the Little Ice Age, respectively. A long-term slight increase in planktonic foraminiferal δ18O values occurs together with a gradual decrease in the δ13C values of both G. ruber and the benthic foraminifera Uvigerina mediterranea. This trend is associated with an increase in sedimentation rates, Ti/Al ratio, magnetic susceptibility, and color index of the sediments. We suggest that this trend shown by various independent proxies seems to be related to the aridification process that started ca. 7.0 ka in the mid-low latitude desert belt and the SE Mediterranean region and continuous until the present. The long-term δ13C decrease shown by surface and bottom water foraminifera reflects a gradual change in the δ13C of the dissolved CO2 of the entire SE Mediterranean water column. This follows the global CO2 rise in the late Holocene as a result of the terrestrial biomass destruction during the aridification process. Moreover the gradual reduction of the vegetation cover in East Africa led to an increased erratic flood-related sediment flux via the Nile River up to the present. This is reflected by the general change in the local sediment composition. At 3.6 ka, the Saharan eolian input reached 65% whereas at about 0.3 ka 70% of the SE Mediterranean sediment was composed of Nile particulate matter.

Original languageEnglish
Pages (from-to)157-176
Number of pages20
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume176
Issue number1-4
DOIs
StatePublished - 25 Dec 2001
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by a grant from the Israel Science Foundation. We thank Dr. G. Almagor for his collaboration in retrieving the cores. We especially thank Prof. L. Labeyrie and Dr. M. Paterne from the Laboratoire des Sciences du Climat et de l’Environnement (CEA-CNRS), Gif-sur-Yvette, France, for the stable isotope analyses of one of the studied cores (planktonic foraminifera). We are very grateful to Dr. Li Ping Zhou from the University of Cambridge, UK, for his help in CI analyses. We thank Prof. Duplessy, Prof. Kallel and Prof. Cita for critically reviewing the manuscript and offering helpful comments for its improvement.

Keywords

  • Climate instability
  • Eastern Mediterranean
  • Environmental changes
  • Foraminiferal isotopes
  • Late Holocene
  • Sediment geochemistry

Fingerprint

Dive into the research topics of 'Global climate instability reflected by Eastern Mediterranean marine records during the late Holocene'. Together they form a unique fingerprint.

Cite this