Late Pleistocene to Mid Holocene landscape reconstruction in the western part of the Thessaloniki Plain (Greece): evidence for environmental changes, and their consequences for the settlement history

Contribution MISTRALS / PALEOMEX - ArcheomedInternational audienceThis study presents new data from four boreholes in order to investigate the palaeoenvironmental changes and landscape configuration from the Late Pleistocene to the Mid-Holocene in the western part of the Thessaloniki plain. Palaeoenvironmental and archaeological records from northern Greece document the occurrence of significant landscape changes during the Holocene. While traces of human occupation are scarce in the western Thessaloniki plain during the transition from the Late Pleistocene (Lateglacial) to the Holocene (Mesolithic period), the climatic and environmental changes involved significant and abrupt impacts on surface processes. Recently published results indicated that palaeoenvironmental transitions in the area influenced the human occupation from the early Holocene (8000/7800 cal. BP) to recent times. However, the Late Pleistocene landscape configuration has not been clearly established. A new sequence is used for analyses of grain size, loss-on-ignition, carbonate content and rock magnetic properties. In addition, a series of 6 new AMS dates from the area provide a precise chronostratigraphy. The synthesis of the environmental proxies reveals distinct palaeoenvironmental changes within a well-constructed chronostratigraphic framework of more than 10k years, which is the longest sedimentary sequence reported for central Macedonia. The Late Pleistocene subsurface occurs at ~9 m depth and clearly indicates the presence of a large alluvial fan deposited by the Aliakmon River during the Younger Dryas (12.7k-11.7kyr BP). The abrupt transition to Early Holocene sediments reveals that a significant influx of fresh water generated a limnic sedimentary environment under detrital and human stress, from pre- to post-reforestation period in the area. Anthropogenic influence is also significantly recorded mainly by the magnetic properties of the lacustrine sediments after 9000 cal. BP. From Neolithic times to the present day, the study area was periodically occupied by a freshwater lake while palaeo-soils are clearly identified by anthropogenic activities and are dated from the Early Neolithic period