Pattern and rate of post-20 ka verticaltectonic motion around Capo Vaticanopromontory (W Calabria, Italy) based onoffshore geomorphological indicators

Abstract

The magnitude and rate of Late Pleistocene – Holocene vertical tectonic movements offshore Capo Vaticano (western Calabria) have been quantified on the basis of the depths of infralittoral prograding wedges (IPWs) and associated abrasion platforms formed during the stillstand of the Last Glacial Maximum (LGM). These features were identified on high-resolution reflection seismic profiles acquired along the continental shelf and upper slope around the promontory. The pattern of vertical movements of the Capo Vaticano promontory is characterized by a marked asymmetry associated with a NE-directed tilt. Removal of the non tectonic component of vertical changes using an ice-volume equivalent eustatic sea-level compilation indicates ~11 (± 5) m of uplift and ~25 (± 5) m of subsidence during the post-LGM from southwest to northeast along the promontory over a distance of ~22 km. The resulting uplift and subsidence rates (including both regional and local components) for the last 20.350 (± 1.35) years are 0.52 (±0.28) mm/ka and 1.23 (±0.32) mm/ka, respectively. Results are consistent with estimates from the analysis of raised Upper Holocene shorelines and from longer-term estimates based on uplifted 215-80 ka old coastal terraces. Integration of offshore and coastal markers indicates a pattern of episodic tilting of Capo Vaticano. Our data provide also evidence that the WNW–ESE striking Coccorino and Nicotera normal faults offshore the SW coast of the promontory were inactive during the post-LGM, and thus are not responsible for tilting of the promontory during the last 20 ka.