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

Indexed In

Volume 140 / 2010

Authors:

Erol SARI, Namık ÇAĞATAY

Keywords:

Sea of Marmara, Sea level change, North Anatolian Fault, hydrothermal activity, submarine mass flow

Abstract:

Sediment cores BUC-10A and ÝZ-30 located on the North Anatolian Fault Zone (NAFZ), 12 km south of Büyükçekmece and Ýzmit Gulf in the eastern part of the Sea of Marmara, respectively, were studied to investigate 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 İZ-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 İZ-30 and BUC-10A give no evidence of hydrothermal activity. A debris flow characterized in core İZ-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 palaeoshoreline dated 9364±64 a BP was also identified in the same core from the İzmit Gulf.