eEarth Discussions www.electronic-earth-discuss.net 1815-3836 1815-3844 4 1 2009 10.5194/eed-4-55-2009 http://www.electronic-earth-discuss.net/4/55/2009/ http://www.electronic-earth-discuss.net/4/55/2009/eed-4-55-2009.html http://www.electronic-earth-discuss.net/4/55/2009/eed-4-55-2009.pdf 55 75 2009-03-24 Holocene evolution and sedimentation rate of Alikes Lagoon, Zakynthos island, Western Greece – preliminary results P. Avramidis pavramid@teimes.gr N. Kontopoulos Technological Educational Institute of Mesolonghi, Department of Aquaculture and Fisheries Management, 30200 Mesolonghi, Greece University of Patras, Department of Geology, 26500 Patras, Greece In the present study we present preliminary results of Zakynthos Alikes lagoon, which is one of the most seismically active regions of Greece. In order to estimate – interpret the Holocene evolution of the area and to reconstruct the palaeonvironmental changes, we based on the data of a 21 m sediment core. Sediment types, structure, colour, as well as contact depths and bed characteristics, were recorded in the field. Standarised sedimentological analysis were carried out, on 46 samples including grain size analysis, calculation of moment measures, and micro- and molluscan fossils of 17 selected samples. Moreover, radiocarbon age determinations have been made on individual Cardium shells from two horizons and whole – core Magnetic Susceptibility (MS) measurements were taken. The interpretation of depositional environments suggests a coastal environment (restricted-shallow) with reduced salinity such as a lagoon margin and in a tidal flat and/or marsh particularly. The maximum age of the study sediments is about 8500 BP. The rate of sedimentation between 8280 BP and 5590 BP was 5.3 mm/yr and between 5590 BP and modern times 1.03 mm/yr. The rate of sedimentation was higher until mid-Holocene while decrease after to 1.03 mm/yr, results which are similar to other coastal areas of western Greece. Aubouin, J. and Dercourt, J.: Zone préapulienne, zone ionienne et zone du Gavrovo en Péloponnèse occidental, Bull. Soc. Gèol. France, 7, t. IV, 785–794, Paris, 1962. Avramidis, P., Bouzos, D., Antoniou, V., and Kontopoulos, N.: Application of grain size trend analysis and spatio-temporal changes of sedimentation, as a tool for lagoon management. Case study: the Kotychi lagoon (western Greece), Geological Carpathica, 59, 3, 261–268, 2008. Bird, E.: Coastline changes. A global review, J. Wiley and Sons, Chichester, 219 pp., 1985. Folk, R. I.: Petrology of sedimentary rocks, Hamphill, Austin, Texas, 1–182, 1974. Kelletat, A.: Holocene sea level curve for the eastern Mediterranean from multiple indicators, Zeitschrift für Geomorphologie N.F., Supplement 137, 1–9, 2005. Kontopoulos, N. and Avramidis, P.: A late Holocene record of environmental changes from the Aliki lagoon, Egion, North Peloponnesus, Greece, Quatern. Int., 111, 75–90, 2003. Kontopoulos, N. and Koutsios, A.: A late Holocene record of environmental changes from Kotihi lagoon, Elis Northwest Peloponnesus, Greece, Quatern. Int., in press, doi:10.1016/j.quaint.2008.10.001, 2009. Kraft, J. C., Rapp, G. (Rip), Gifford, J. A., and Aschenbrenner, S. E.: Coastal change and archaeological settings in Elis, The American School of Classical Studies at Athens, Hesperia, 74/I, 1–39, 2005. Lekkas, E.: Neotectonic map of Greece, Zakynthos – Volime, scale 1:50000, University of Athens, 116 pp., 1993. Underhill, J.: Triassic evaporites and Plio-Quaternary diapirism in western Greece, Journal of Geological Society of London 145, 269–282, 1988. Vött, A.: Relative sea level changes and regional tectonic evolution of seven coastal areas ni NW Greece since the mid-Holocene, Quaternary Sci. Rev., 26, 894–919, 2007. Zelilidis, A., Kontopoulos, N, Avramidis, P., and Piper D. J. W.: Tectonic and sedimentological evolution of the Pliocene – Quaternary basins of Zakynthos, Greece: Case study of the transition from compressional to extensional tectonics, Basin Res., 10(4), 393–408, 1998.