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

Doctoral Dissertation uoadl:1309250 883 Read counter

Unit:
Τομέας Ιστορικής Γεωλογίας και Παλαιοντολογίας
Library of the School of Science
Deposit date:
2013-01-07
Year:
2013
Author:
Κοντακιώτης Γεώργιος
Dissertation committee:
Δρ. Μ.Δ. Δερμιτζάκης Ομότιμος Καθηγητής ΕΚΠΑ, Δρ. Α. Αντωναράκου Επίκ. Καθηγήτρια ΕΚΠΑ, Δρ. Μ. Τριανταφύλλου Αναπλ. Καθηγήτρια ΕΚΠΑ
Original Title:
Παλαιοωκεανογραφική και παλαιοκλιματική μελέτη της Ανατολικής Μεσογείου κατά το Ανώτερο Τεταρτογενές με βάση τις συγκεντρώσεις των πελαγικών τρηματοφόρων
Languages:
Greek
Summary:
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 tops along a N–S Aegean Sea transect in
order to figure out how accurately the Mg/Ca ratio in foraminiferal calcite
reflects the ambient temperature.
Keywords:
Planktonic foraminifera, Paleoclimatology, Bioecozones, Mg/Ca paleothermometer proxy, Eastern Mediterranean
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
463
Number of pages:
381
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