Age determination for segments of the North Anatolian Fault (NAF) northern branch by 234U/230Th dating of Soğucak (Yalova) range-front travertines, south Marmara, Turkey

The Soğucak travertine occurrences developed along north segment of the North Anatolian Fault (NAF) in Yalova province, Marmara Region, Turkey. The range-front type travertines outcropping over an approximately 1 km2 area with 20-40 m thickness are middle-thick bedded and back-tilted southward or horizontally. Lithology of the travertines includes physolite, stalactites-stalagmites, cave pearls, sharp pebble carbonate nodules, spherical-roller-intricate shapes and laminated banded travertines. Geochemical analysis was performed on six samples of the travertines. The samples showed high calcite composition (averagely 98%) and Mg carbonite content varying from 0.87 to 1.33%. The travertines were deposited by means of normal faults as indicated by structural and morphological relationship with active tectonics. 234U/230Th dating of the travertines provided an age range from 61.318 (±3.091) to 231.944 (±141.902) ka. Findings show that the travertine deposition and deployment of faults in the region occurred approximately at 231 ka, corresponding to Middle Pleistocene. Therefore, the age of both travertines and NAF was determined as Middle Pleistocene.