Unit:
Department of Geology and GeoenvirommentLibrary of the School of Science
Author:
Giamali Christina
Dissertation committee:
Ευτέρπη Κοσκερίδου Καθηγήτρια, τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Βασίλειος Καρακίτσιος, Ομότιμος Καθηγητής, τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Ασημίνα Αντωναράκου, Καθηγήτρια, τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Γεώργιος Αναστασάκης, Καθηγητής, τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Χαρίκλεια Ντρίνια, Καθηγήτρια, τμήμα Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Αριστομένης Π. Καραγεώργης, Διευθυντής Ερευνών, Ελληνικό Κέντρο Θαλασσίων Ερευνών
Γρηγόρης Ρουσάκης, Διευθυντής Ερευνών, Ελληνικό Κέντρο Θαλασσίων Ερευνών
Original Title:
Multiproxy paleoenvironmental and paleoclimatic analysis in biota-rich sediments of North and South Aegean Sea during the last 21 ka
Translated title:
Multiproxy paleoenvironmental and paleoclimatic analysis in biota-rich sediments of North and South Aegean Sea during the last 21 ka
Summary:
Aspects of paleoclimatic and paleoceanographic evolution of the north Aegean Sea through the late Quaternary are revealed by the study of quantitative variations in planktonic foraminiferal, and pteropodal assemblages (including multivariate statistical approach; principal component analysis (PCA)), the isotopic composition of planktonic foraminifera (δ18O and δ13C); and hydrographic-related indices (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), upwelling (U-index), seasonality), extracted from three high-sedimentation rate cores from the North and South Aegean Sea (North Aegean Trough and the submarine area between Kimolos and Sifnos islands). Based on the statistical analysis, besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, primary productivity, water column stratification, and seasonality also control the planktonic foraminifera and pteropod communities during the late Quaternary. Pteropod fauna during the Holocene and especially the sapropel deposition were recorded for the first time in the Aegean Sea.
Focusing on last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel layer/sublayers, with extremely warm and stratified conditions S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP) in the south Aegean Sea and warm and humid phase at the north Aegean Sea (9.6–6.1 ka BP).
The Holocene climatic instability of the study area is further supported by six episodes of brief cooling in the North Aegean (NAEGC6–NAEGC1) centered at 9.30, 8.05, 7.05, 4.55, 3.55, and 2.05 ka BP, and two in the south Aegean Sea (SAEGC2–SAEGC2) centered at 7.35 and 5.35 ka BP, reflected by significant faunal changes and oxygen isotope enrichments. These cold/arid events are coeval with equivalent cooling events that have been described in different basins of the Mediterranean Sea, while signal similarities with equivalent changes in the intensity of the Siberian high suggest a climatic link between the studied area and the high-latitude areas.
Main subject category:
Science
Keywords:
planktonic foraminifera, pteropods, paleoenvironment, paleoclimate, Late Quaternary
Number of references:
289
