The Magdala site (Kinneret Lake, Israel) and its harbour history: evidences of anthropogenic and tectonic-climatic sedimentation control during the Late Holocene

Recent excavations at the ancient city of Magdala located on the west side of the Kinneret lake (Israel) have unearthed a harbor structure with four mooring stones at an altitude of 208.32 m bsl, suggestive of a higher lake-level in respect to the previous hypothesis. Furthermore the geometrical relationships between the anthropogenic structures and sedimentary deposits suggest several lake- level fluctations up to some meters during the last 2 ky. On the basis of a multidisciplinary approach, involving sedimentological, geophysical, micropalaeontological (benthic meiofauna and pollen) and geochemical analyses three small sedimentary sequences have been identified. These sequences, few decimeter thick, reflect palaeoenvironmental changing in the harbor area and consist in a: 1) a pre–harbor foundation sequence, 2) a sin-harbor activity sequence, and 3) an harbor- abandonment sequence. Above the natural sandy shoreface deposits the abrupt transition to clayey silt dark deposits reveals an anthropogenic sedimentary control related to the activity of the harbor. The following depositional sequence records the siltation of the harbor and its abandonment. Sands sharply overlaid by a foreshore to backshore conglomeratic unit constitute these deposits. Another conglomeratic unit outcrops upward in the stratigraphic sequence. The sudden appearance of conglomerates litofacies at two different stratigraphic levels are possibly correlated to climatic changes from a rainy to an arid phase and/or to tectonic events such as the destructive earthquakes occurred in the 349 AD and in 749 AD