SEA LEVEL AND PALEOENVIRONMENT DURING ROMAN TIMES INFERRED FROM COASTAL ARCHAEOLOGICAL SITES IN TRIESTE (NORTHERN ITALY)

Paleoenvironment and sea level markers have been studied from new and published data at two archaeological sites in Trieste. Results allowed to locate the Roman Age shoreline, presently buried under the city. Archaeological data clearly indicate the presence of a well-organized Roman Age seaside, which gradually moved offshore. Imperial Roman Age structures have been found at the site located close to the Curia building. Archaeological finds indicate the subsequent widening of the seafront. During the 1st century BC, a stone wall parallel to the coast already existed at the back of a sandy beach. After the widening of the city, a large quay was built and the seafront moved offshore, covering the former Imperial Age structures. The quay was used up the 4th century AD. Late Roman Age structures have been found at the site called Cavazzeni. The period when the site was abandoned is clearly indicated by the construction of the Medieval walls overtopping the Roman Age structures. The presence of two docks located just in front of the site are reported in several sketches, maps and historical sources dated at the 16th-17th century. Microfaunistic composition of sediments indicates that protected sectors of the harbour were built in order to allow the recovering of ships and other coastal activities. Archaeological finds together with paleoenvironmental data suggest that vertical tectonic movements in the urban area of Trieste are significantly lower in respect of the Northern Adriatic. In fact, the presence of marine deposits with bad-preserved microfossils at elevations higher than present-day mean sea level is related to the possible occurrence of a violent storm or a tsunami event. For the latter case, radiocarbon date suggests a possible correlation to the 361 AD earthquake occurred along the Eastern Adriatic coasts.