MIS 9 to MIS 5 terraces along the Tyrrhenian Sea coast of Latium (central Italy): Assessing interplay between sea-level oscillations and tectonic activity

Abstract

We present a review of the geomorphology of the Tyrrhenian Sea coast of central Italy integrated by a novel structural-geomorphological study coupled with statistical analysis of topographic culminations and comparison with a Digital Elevation Model, aimed at reconstructing a suite of paleo-surfaces corresponding to remnant portions of marine terraces. We performed geochronological, sedimentological, micromorphological and mineralogical investigations on the deposits forming the different paleo-surfaces between Civitavecchia and Anzio towns, in order to provide chronostratigraphical, paleogeographical and paleoenvironmental constraints. Using the newly achieved dataset we correlate these paleo-surfaces with the coastal terraces formed during past sea-level highstands, as recognized by previous studies, and we refine their correlation with the Marine Isotope Stage (MIS) timescale.

In particular, we have extended our geomorphological analyses landward in the area between the Tiber River mouth and Anzio, in order to include the oldest paleo-surface developed above the deposits of the last large explosive eruption at 365 ± 4 ka in the Colli Albani Volcanic District. Results of this study allow us to recognize a set of higher paleo-surfaces at elevation ranging 108 thought 71 m a.s.l., which we interpret as one tectonically displaced, widespread coastal terrace originated during the MIS 9.1 highstand. We correlate the previously identified paleo-surfaces of 66–62 m a.s.l. and 56–52 m a.s.l. with the equivalent coastal terraces developed during the sea-level highstands of sub-stages 7.5 and 7.3/7.1. Moreover, based on data from literature on relative elevation of maximum sea level during the highstands of MIS 11 through MIS 5.1, we assess the regional uplift and the concurrent tectonic displacements that have occurred since 900 ka in this area.