LATE PLEISTOCENE AND HOLOCENE SEA-LEVEL CHANGE IN GREECE AND SOUTH-WESTERN TURKEY - A SEPARATION OF EUSTATIC, ISOSTATIC AND TECTONIC CONTRIBUTIONS

Sea-level change during Late Pleistocene and Holocene times is a combi nation of eustatic, isostatic and tectonic contributions. In the centr al Mediterranean Sea region of Greece and western Turkey, the isostati c components are important, due to the changing gravitational potentia l of the Earth, the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans, in cluding the Mediterranean. Changes in relative sea-level due to these glacio-hydro-isostatic adjustments have reached amplitudes of 1 mm yr( -1) during the last few thousand years. A model for the isostatic cont ribution to sea-level change, including the movement of shorelines due to the combined eustatic-isostatic changes, is developed, based on ea rth-model and ice-sheet parameters estimated from sea-level observatio ns from other areas. Comparisons of this model with observations of se a-level change permit rates of vertical movement to be estimated for L ate Holocene time. Allowance for the isostatic factors makes a signifi cant difference to these rates. The plains of Argolis, Lakonia, Messin ia and Navarine, in the southern Peloponnese, for example, appear to b e tectonically stable on time-scales of a few thousand years and longe r, consistent with the position of the Last Interglacial shoreline clo se to the present-day sea-level. The observations here, of a rising se a-level, are largely the consequence of the glacio-hydro isostasy and not of a long-term tectonic process. Crete as a whole is subject to te ctonic uplift, but at variable rates, and forms part of an arcuate zon e of uplift extending from Rhodes and Karpathos in the east to Kithera in the west at rates that locally exceed 4 mm yr(-1). The southern sh ore of the Gulf of Corinthos is also subject to uplift at rates approa ching 1.5 mm yr(-1). These isostatically corrected estimates for the p ast few thousand years are in agreement with longer-term estimates bas ed on the position of the Last Interglacial shoreline. Only on the Per achora Peninsula do the tectonic rates over these two time intervals a ppear to be in disagreement, with the Late Holocene rates being much h igher than the long-term rates.