Morphological and sedimentological characteristics of a cuspate foreland (Mytikas Epanomi, east Thessaloniki city, Greece)

Περίληψη

Cuspate foreland is a geographical feature developed in a long shore drift or lakeshores. It is formed in a downwind area of an island or a coast, or at the end of a river where the conditions are appropriate by the incremental progress of sand and gravels in a triangle shape. The formation of the shape depends on the wave refraction and the deposition of sediments at the two sides of the triangle. Some cuspate forelands are flushed with floras which emigrated from the main land and they consist of many geomorphological features, like the lagoon and different types of dunes. Such kinds of ecosystems are sensitive to the human’s activity and nature. The subject of this research was the ecological history and geomorphological characteristics of such a cuspate foreland. To this purpose, electric resistivity tomography (ERT) method was employed to map the vertical sequence of sediments in such an environment. The research was focused on a specific cuspate foreland at ‘Mytikas’ in Epanomi, close to Thessaloniki. The main purpose of the work was to map the surface sediments as well as the stratigraphy in depth and to record all the features that are developed on it and which contributed to the forming of this ecosystem. Mytikas is a wealthy ecosystem, with triangular shape, demarcated by two streams. It has a variety of dunes, which extend on both sides of the triangle. In the inland, there is a chocked lagoon with a diameter of 5.5 km (Kjerfve,1986), which hosts many kinds of birds. Accretion zones are found on the South side of the cuspate foreland and the main direction of the wind on this side is towards the North. Based on the sedimentology and pipette analysis of the sediments collected from the surface and the lagoons, the area is composed of grit sandy mud. Another part of the research was focused on mapping the surface features. In this specific figure, were extracted the results for the shape of the secondary dunes, which gave information for compiling an elevation model of the dunes. Nine ERT profiles in total were measured in the study area. The images that have been produced by the ERT data inversion, allow the estimation of the age of the cuspate foreland, as well as the age of the lagoon. Another ERT was applied to correlate the resistant layers with the stratigraphy of the area in general.