Vegetation history, human impact and palaeogeography of West Estonia : Pollen analytical studies of lake and bog sediments

Sammanfattning: The history of Holocene vegetation in western Estonia and the West Estonian Archipelago is described. Early Holocene sea level changes in the area are reconstructed, and human impact on the vegetation during the Late Holocene is discussed West Estonia was divided into five study areas (Rummu-Maardu, Mustjärve, Velise-Kiilaspere, Tôstamaa Peninsula, and northern Saaremaa in the West Estonian Archipelago, from north to south). Lake and bog sediments were surveyed and cored. Precise isolation altitudes were determined for the thresholds of the investigated basins, buried organic matters and coastal formations. Cores were analysed for pollen content and dated using AMS and conventional 14C methods. Additional analyses were performed, including loss-on ignition, macro fossil, green algae Pediastrum, mineral magnetic analyses and climatic reconstruction. Palaeogeographic reconstructions based on shoreline displacement curves of different stages of the Baltic Sea reveal the maximum of the Ancylus Lake level ca. 9100-9000 BP and the Litorina Sea, 6900-7100 BP. Cereal Pollen appeared in the area about 4700 BP (3400 BC). The cultivation of cereals, connected to the Boat-Axe Culture, remains stable throughout the Bronze Age, and expands noticeably at the Late Bronze Age-Pre-Roman Iron Age transition, 800-500 BC.