Tectonic effects on Late Holocene sea level changes in the Gulf of Trieste (NE Adriatic Sea, Italy)

A multidisciplinary approach has been used to evaluate Late Holocene relative sea level change along the eastern coast of the Gulf of Trieste. Published data, together with new 14C dating, have been compared with predicted curves in order to evaluate the tectonic behaviour of the studied area. Observations derived from precise geomorphological, archaeological and sedimentological measurements dated from 10 ka cal., sampled at elevations ranging between −25 and +0.10 m. Tectonic rates range from 1.01 mm/y (Gulf of Trieste) and –1.99 mm/y (Villaggio del Pescatore), but are probably higher in the northwestern sector, where the elevation of post-Roman geomorphological markers is lower. A detailed surveying of notches, beachrocks, submerged shore platforms and the geological setting of the coastal area highlight the variability of tectonic subsidence, indicated by geophysical data collected in the central part of the gulf. Analyzed data indicate active tectonism. The tectonic setting of the northernmost sector is affected by the presence of strike-slip faults which cause differential downdrop of the shoreline, as suggested by significant increases of notch depths, ranging between −1.0 m and −2.7 m.