부산대학교 도서관

This study deals with the palaeogeographic evolution of the Alykes lagoon, located on the western coast of the Thermaikos Gulf in northern Greece. For this purpose, detailed geomorphological mapping was conducted and two shallow boreholes were drilled in an attempt to recognize the late Holocene palaeoenvironmental changes. In total 64 sediment samples collected from the cores were granulometrically and palaeontologically analysed. Moreover, two shell samples were 14C dated and provided the chronostratigraphy of the cores. Four biosedimentary units were identified corresponding to different depositional palaeoenvironments including coastal shallow marine, lagoonal, mesohaline to oligohaline and brackish mesohaline respectively. A shallowing upwards sedimentary sequence was recorded with the lower unit corresponding to a shallow marine environment which progressively changes to a more protected lagoonal one, with restricted communication to the open sea. Based on the radiocarbon dates it is evident that the coastline was located a few hundreds of meters west of the present-day one by the end of the seventh millennium BP. Furthermore, we concluded that the establishment of the lagoon can be safely put around the sixth millennium BP and that its confinement can be attributed to the formation and evolution of two groups of beach ridges located at the eastern part of the lagoon. The fining upwards sequence of the sedimentary record of the cores is interrupted by a coarse-grained layer corresponding to a high energy marine inundation event attributed probably to a palaeotsunami which occurred not long before 4330–3920 cal BP. No, or negligible, vertical tectonic displacement can be concluded, for the past 4330–3920 cal BP.