SEDIMENT CORE STUDIES ON THE NORTH ANATOLIAN FAULT ZONE IN THE EASTERN SEA OF MARMARA: EVIDENCE OF SEA LEVEL CHANGES AND FAULT ACTIVITY

Abstract

Sediment cores BUC-10A and ÝZ-30 located on the North Anatolian Fault Zone (NAFZ), 12 km south of Buyukcekmece and Ýzmit Gulf in the eastern part of the Sea of Marmara, respectively, were studied to inves- tigate tectonics and paleo-oceanographic processes, using sedimentological and geochemical methods. Total inorganic carbon (TIC as total calcium carbonate) and total organic carbon (TOC) contents in core BUC-10A range between 12.1-34.3 and 0.5-4.1 dry wt. %, respectively. The organic matter-rich sapropel unit was identified between 1.60 and 2.43 m below sea floor (bsf) in this core. The concentration ranges of the metals in core BUC-10A were: Cr: 55-96, Cu: 21-37, Ni: 63 39-74, Mn: 345-693, Pb: 19-34, Zn: 79-143 ppm and Fe: 2.30-3.15 dry wt. %. The concentration ranges of TOC, TIC, Cr, Cu, Fe, Ni, Mn, Pb and Zn in core ÝZ-30 were 0.40-1.70 %, 0.25-31%, 39-87 ppm, 13-32 ppm, %2.10-4.80, 18-41 ppm, 315-528 ppm, 7-21 ppm and 78-185 ppm, respectively. Chalcophile element (Fe, Mn, Cu, Pb, and Zn) concentrations in cores ÝZ-30 and BUC-10A give no evidence of hydrothermal activity. A debris flow characterized in core ÝZ-30 and dated 3276±48 a (calendar) before present (BP) was most likely triggered by tectonic activity in the Ýzmit Gulf. Sediments of 49.5 mbsf palaeo- shoreline dated 9364±64 a BP was also identified in the same core from the Ýzmit Gulf.