New insights into the uplifted Roman harbour at Mavra Litharia (N Peloponnese, Greece) in the geodynamic context of the southern margin of the Corinth Gulf

Abstract

Recent archaeological excavations at Mavra Litharia in the area of Aigeira (N Peloponnese) have brought to light the eastern landward extension of a jetty. The erosion of the cliff along the modern coast and the excavations at the inner side of the northern coastal section of the jetty provided a clearer picture of its structure, significantly different than this presented in previous studies.The harbour installations are assigned to between the 2nd century and the first half of the 3rd century AD, according to the study of the structure, the mobile findings and the epigraphic data. Biomarkers attached to the structure define the sea level during its operation and demonstrate the current uplift position. The observed damage that has sustained the structure of the ancient jetty suggests that its destruction was co-seismic and reveals the direction of seismic waves from the west. Reconstruction of the displaced blocks of the jetty in their original position, archaeological interpretation and dating of the structure, biomarker information, and glacio-isostatic modelling, determine the sea level since the function of the harbour and the uplift of the ancient jetty as 5.35 ± 0.37 m.The age of the biological indicators 1686 cal ΒP (264 AD) is consistent with archaeological dating and the period of the sudden abandonment of the under-reconstruction nearby theatre of ancient Aigeira (mid-3rd century AD). The uplift of the Roman harbour occurred at least in two phases, initially by 4.35 m around 1686 BP and subsequently by 1.0 m around 657 BP.The mean tectonic uplift rate of 2.81 ± 0.20 mm/yr for the coast in Mavra Litharia, similar to these for the entire western part of the south shore of the Corinth Gulf, is higher than the mean uplift rate of 1.21 ± 0.28 mm/yr in the easternmost edge. The westernmost edge at the Rio-Antirio strait presents very high subsidence rate of 5.17 ± 0.47 mm/yr.