Παλαιοωκεανογραφική και παλαιοκλιματική μελέτη της Ανατολικής Μεσογείου κατά το ανώτερο τεταρτογενές με βάση τις συγκεντρώσεις των πελαγικών τρηματοφόρων

• Main Authors: Kontakiotis, Georgios, Κοντακιώτης, Γεώργιος
• Format: Doctoral or Postdoctoral Thesis
• Language: Greek
• Published: National and Kapodistrian University of Athens 2013
• Subjects: Ανατολική Μεσόγειος; Πλανκτωνικά τρηματοφόρα; Παλαιοκλιματική αναπαράσταση; Βιο-οικοζώνες; Παλαιοθερμοκρασιακή μέθοδος Mg/Ca; Επίδραση της αλατότητας; Διαγένεση; Βιοστρωματογραφία ανώτερου τεταρτογενούς; Eastern Mediterranean; Planktonic foraminifera; Paleoclimatic reconstruction; Bio-ecozones; Mg/Ca paleothermometer proxy; Salinity effect; Diagenesis - Overgrowth effect; Biostratigraphy late Quaternary; Φυσικές Επιστήμες; Γεωεπιστήμες και Επιστήμες Περιβάλλοντος; Natural Sciences; Earth and Related Environmental Sciences
• Online Access: http://hdl.handle.net/10442/hedi/28627; https://doi.org/10.12681/eadd/28627

The overall objective for this PhD-study was to reconstruct palaeoclimate and palaeoceanographic conditions and further extend our knowledge of the climatic variability in the eastern Mediterranean Sea during the Late Quaternary. In order to advance the understanding of the spatial and temporal variability of observed climatic and oceanographic changes and elucidate forcing mechanisms, this study aimed at achieving high resolution sediment cores at sub-centennial to centennial scale. The distribution pattern of the planktonic foraminifera species identified in Aegean and Libyan cores has been analyzed and used for the biostratigraphic analysis, the unraveling of the palaeoclimatic history, the determination of the surface conditions, the orbital configuration of the climatic changes and the sediment cyclicity of the cores. The selected marine cores were investigated using several paleoceanographic proxies. These include planktic foraminiferal fauna distributions, palaecological reconstructions through multivariate statistical analyses (Q-mode, R-mode cluster analyses and principal component analyses), sea surface temperature (SST) reconstructions based on planktic foraminifer species counts (the planktonic palaeoclimatic curve used as an index of SST) and measurements of stable isotopes (δ18O, δ13C) in selected foraminiferal tests (Globigerinoides ruber (w)). Foraminiferal concentrations as well as humidity (H-index, runoff), temperature (T-index), stratification (S-index) of the water column and seasonality (Sn-index) biomarker indices that provide important information on palaeoceanographic and climate dynamics and gradients were also used. Additionally the relatively new paleothermometer, Mg/Ca-ratio, was applied on the same foraminiferal species with stable isotope analyses to test and examine its applicability in subtropical and high-salinity environmental settings. The influence of external factors like diagenesis and salinity on the T-signal in Mg/Ca was extensively investigated in a series of modern core ...