Geomorphological mapping, a basic tool for interpreting rock coasts landforms: an example from Eastern Liguria (Italy)

Abstract

This work deals with the geomorphological setting, with particular regard of rock coast morphologies along the coastline, of Palmaria Island, in the easternmost part of the Ligurian coast. We carried out a detailed geomorphologic survey on the island, focused on coastal landforms. The rock seaward slope of Palmaria Island has two types of long profiles: 1) a slope over wall profile (plunging cliff) and 2) narrow rock surfaces at sea level or a few meters above it backed by steep slopes (palaeocliff). The first type of slope profile is due to the presence of faults, linked to NW-SE-striking fault system, responsible for the displacement of the eastern Ligurian continental shelf. Our data indicate the up-throw side of the fault, corresponding to the island coast, is stable, so that an incipient notch can evolve along the cliff face in connection with present day sea level. The second type of slope profile shows at its bottom a narrow, discontinuous rock platform which is currently being demantled, constrained in elevation below 5 m asl. This surface is interpreted as inherited from a past interglacial phase, thanks also to the OSL dating of a scree slope deposits that overlaps it.