The krathis lake, one century of evolution.

A riverbed swamp in the Krathis River, N. Peloponnese, is studied and analyzed geomorphologicaly. Our analysis is also based on sedimentological, geochemical, palaeontological and radiometric dating data which enabled the investigation of the possible relationship between the studied swamp and the 1913 Tsivlos landslide. Sedimentological analysis showed that the current sedimentation is dominated by fine grain material and occasional coarse-grained beds. Micropalaeontological analysis indicated that the deeper layers of the core are barren, while the upper ones contain fresh water ostracods suggesting hydrodynamically a progressively more stable environment. In accordance, radiocarbon C14 and 137Cs dating showed a progressively decreasing sedimentation rate over the last fifty years. The results of this study show that the Tsivlos landslide is not the only cause for the formation of the modern swamp. Tectonic movements in the area seem to play a decisive role causing uplift and subsidence in the area near an active fault.