Geomorphological mapping and relief evolution of the Dokali River catchment near Demonià (South-western Lakonia, Greece) / Cartographie géomorphologique et évolution du relief du bassin versant de la rivière Dokali près de Démonia (Laconie du sud-ouest, Grèce)

摘要

Abstract Open to the sea in the Demonià area, the Dokali basin, inside the Lakonia graben, constitutes a relief unit representative of the landscape of the entire western coast, from Molaoi to Neapolis. A survey was carried out for the purpose of reconstructing the geomorphological evolution of this typical Mediterranean coastal region. The attached map summarises the work accomplished and this paper deals mainly with the explanatory notes. Structural landforms are here strictly tied to a particular situation deriving from the overriding of carbonate rocks, belonging to the Gavrovo-Tripolitza nappe, on the metamorphic complex of the Lower Western Hellenic nappe (phyllites, quartzites and evapo- rites). In the inner Dokali basin a thick series of Plio-Quaternary marine sediments filled a composite structural and morphological depression. In this context exogenous processes (slope, fluvial, karstic and coastal) have generated a highly dissected topography, controlled by the sharp contrast between the two above mentioned lithological complexes, and involving differential weathering. Some different types of cal- crete have also been found on the slopes, providing further information about the long-term evolution of the landscape. The successive stages of landscape development are summarised as follows: 1) palaeo-relief (altitude between 400 and 500 m above palaeosea level) consisting of plateaux, flat divides, ridges and valleys; 2) first incidence of significant uplift and deep incision of the Dokali River fluvial system up to 100 m a.s.l.; 3) long period of stability, allowing 1 km of slope recession and pediment formation; 4) second incidence of limited uplift, followed by a renewed valley incision to below the present sea level; 5) Neogene marine ingression and consequent filling of the valley up to 100 m a.s.l.; 6) Quaternary eustatic sea level changes, with new cycle of valley incision and formation of marine terraces.