Buried and submerged greek archaeological coastal structures and artifacts as gauges to measure late holocene seafloor subsidence off Calabria, Italy

摘要

This synthesis integrates recently acquired archaeological and geological data with earlier documented observations to shed light on the subsidence of ancient Greek coastal facilities in southern Italy. These are now positioned between former shorelines and inner shelf sectors at five Calabrian margin localities. Submergence of coastal to inner shelf facilities has resulted in part from sea-level rise by about 2 m associated with glacio-hydro-isostatic factors since archaic to classic Greek time. This phenomenon alone, however, does not explain the wide variation of measured subsidence rates from site-to-site. The marked lowering of coastal site substrates by seismo-tectonic activity (including extensional fault motion), stratal readjustments at depth, and compaction of underlying sediment sequences is significant. Four of the subsided facilities are positioned near emerged Calabrian areas where prevailing Holocene average annual land uplift rates range to ?1.0 mm/yr; at the fifth, near Hipponion, terrains have risen by nearly 2 mm/yr. In marked contrast, submerged and/or buried structures record the following late Holocene long-term average rates of coastal margin subsidence: Sybaris-Thuri on the Taranto Gulf margin (?0.5-1.0 mm/yr); Hipponion-Vibo Valentia along the Tyrrhenian coast (?0.8 to ?3.2 mm/yr); and Locri-Epizefiri, Kaulonia, and Capo Colonna on Calabria's Ionian margin (?1.6, ?1.6-2.4, and ?4.0 mm/yr, respectively).