Factors in the development of rocky coasts between Lerici and Tellaro (Gulf of La Spezia, Liguria, Italy)

Abstract

The evolution of rocky coasts has been described by several Authors as the result of different interacting factors, referred to as littoral forces, either internal (tectonics, volcanism, seismicity) or external ones (atmospheric, hydrospheric, biospheric and cryospheric). Rocky coasts between Lerici and Tellaro (Gulf of La Spezia, eastern Liguria, Italy) present some features that are intermediate between shore platforms and plunging cliffs. Four types of profile have been identified; they have near-horizontal to steep surfaces, often showing an almost vertical step in the seaward margin. These forms were initially interpreted as wave-cut platforms suspended at different heights from sea level by simple eustatic oscillations. In this work, a polygenetic origin is proposed for these forms, in which tectonics, weathering, wave action and inheritance are all involved.