Paleoenvironmental evolution of Lousoi lake, during the Holocene, Northern Peloponnese, Greece

• Κύριος συγγραφέας: Σταμάτης, Διονύσιος
• Άλλοι συγγραφείς: Stamatis, Dionysios
• Γλώσσα: English
• Έκδοση: 2021
• Θέματα: XRF scanning; Radiocarbon dating; Paleoenvironment reconstruction; Paleoclimate; Μέθοδος ραδιοχρονολόγησης; Παλαιοπεριβαλλοντική ανασυγκρότηση; Παλαιοκλίμα

The following master thesis presents sedimentological and geochemical results from the drained lake of Lousoi, Achaia, Greece. The aim of this study is to analyze the paleoenvironmental evolution of the area, the last 10000 years, through the study of an 7m depth core and compare the results with other lacustrine records from the Peloponnese. For this study, a sediment core, LS, was obtained using an Eijkelkamp percussion corer. Sediment types, structure, color, and sediment structures were recorded in the field, and then the core was packed and transferred to the Lab of Sedimentology, in the Geology Department of Patras University, for further analyses. Standard sedimentological analyses were carried out on core samples including (1) grain size analysis, and calculation of moment measures, such as mean, sorting, kurtosis, and skewness, (2) RGB measurements, (3) Total Organic Carbon (TOC), (4) (5) Total Nitrogen (TN), (6) Calcium Carbonate Content (CaCO3) and (7) measurements of pH and EC (electrical susceptibility). Radiocarbon dating 14C was carried out in seven different samples throughout the LS core. For the geochemical analyses, samples, size 5cm long and 4cm wide, were extracted from the LS core. The samples were then analyzed at the lab of Sedimentology by using a handheld XRF scanner. Chemical elements such as Al, Si, K, Ca, Ti, Mn, Fe, Rb, Sr, Zr, Zn, were analyzed. The interpretation of the sedimentological and geochemical data distinguished three distinct evolutionary stages of the Lousoi lake: • A limnic stage between 10900-8850 cal BP • Α transition stage between 8850-6150 cal BP and, • Α stage characterized by seasonal flooding between 6150-110 cal BP. The comparison of the lacustrine records for the last 5000 years revealed two periods where all sites displayed similar climatic conditions. • A wet period between 4150-3600 cal BP and, • a dry period between 1400-110 cal BP. Although all five geoarchives show evidence for periods with similar conditions, their timing and duration display considerable site-to-site differences. This may be attributed to the high regional geographical diversity within the Peloponnese, in combination with age uncertainties and site-specific responses in individual ecosystems, which may explain some deviations. Moreover, no dramatic shift was observed in the proxies, which would hint towards rapid climatic changes with a severe impact on the human population, but rather gradual variations were more noticeable. Thus, climatic changes may have been only one factor in a multi-causal interaction network that contributed to but did not cause social transformation.