Holocene coastline evolution of Procida Island, Bay of Naples, Italy

Abstract

We studied the sea-level change and the volcano-tectonic behaviour of the pericoastal belt of Procida and Vivara islands, which are part of the insular Phlegraean Fields in the Naples Bay, southern Italy, on the basis of geological, geomorphological, and archaeological markers. The recognition of two outcrops of submerged beachrocks and the use of many different archaeological remains allowed us to better constrain the morpho-evolutionary history of the study area in term of both temporal and palaeoenvironmental reconstructions. The archaeological heritage of the Phlegraean area is very rich, spanning from the Bronze Age to the Middle Age and presenting a high density of evidence, also in the submarine environment. The submarine geomorphological survey furnished numerous new data for the construction of reliable eustatic and subsidence curves. Three major episodes of subsidence can be recognized in the Phlegraean area, in the Bronze Age, Roman period, and Middle Age. The events related to the oldest period have been linked to the history of the Vivara–Procida geoarchaeological system, whereas the subsequent episodes recorded in the study area have been correlated to the Roman and Medieval episodes of subsidence recorded in part of the continental Phlegraean area. The sea-level curve reveals some differences with regard the other similar curves from the continental area, both in the amount of subsidence in single time intervals and for the absence of positive motion during the post-Roman period. The curve relative to the subsidence rates is characterized by a cyclic alternation of periods with different rates, with a frequency of about 2 ky, due to the inversion of the volcano-tectonic vertical mobility.