High resolution LGM-present paleoceanography of the NE Mediterranean

• Main Author: Abu-Zied, Ramadan Husain
• Format: Thesis
• Language: English
• Published: University of Southampton 2001
• Subjects: Planktonic foraminifera
• Online Access: https://eprints.soton.ac.uk/467044/; https://eprints.soton.ac.uk/467044/1/794314.pdf; https://eprints.soton.ac.uk/467044/2/794314_data.zip

Unprecendently high-resolution study, based on oxygen and carbon isotopes and abundances of both benthic and planktonic foraminifera, has been carried out on cores SLA-9, SL-31, LC-21 and LC-31 from the central Aegean and NE Levantine Seas. We discover several distinct variations both in the isotopic and abundances of the faunae throughout the interval from the Last Glacial Maximum to the Present, which have been interpreted in relation with the bottom water environmental changes. During the deposition of the ~30-15.5 ka BP-interval, the occurrence of high faunal density and diversity dominated by the epifaunal taxa (e.g. C. pachydermus and miliolids) and shallow infaunal taxa (e.g. U. peregrina and B. spathulata ) suggests that bottom water of the eastern Mediterranean was very well ventilated with normal, stable conditions and stable, high flux of organic matter to the sea floor. This organic matter flux was higher at the shallower sites than at the deeper sites, as might be expected with a normal depth-dependent decrease of the organic matter flux to the sea floor. During the 15.5-10 ka BP-interval, dominance of the opportunistic taxa (e.g. G. orbicularis and G. altiformis ) at the expense of both epifaunal and shallow infaunal taxa would suggest an intensive seasonal pulse of organic matter to the sea floor accompanied by reduced deep-water ventilation leading to decrease in the amount of the dissolved oxygen at the deep-sea environment and hence disappearance of epifaunal taxa and shallow infaunal taxa. The S1 internal (10-6 ka BP) was deposited under dysoxic/anoxic conditions in the bottom waters as indicated by the dominance of deep infaunal taxa ( G. affinis and C. mediterranensis ).