U-Th Ages and Facies Properties of Edremit Travertines and Tufas, Van, Eastern Anatolia: Implications for the Neotectonics of the Region

Abstract

Travertine formation is one of the most important archives of active tectonics in a region and provides information about climate, water temperature and quantity, and biological activity. The Edremit travertines and tufas extend over nearly160 km(2) within the boundaries of the Edremit area to the east of Lake Van (eastern Turkey), and yield important evidence towards understanding the neotectonics of the region. The Edremit travertines and tufas were studied throughout their full stratigraphic extent, the factors controlling the formation of these deposits were examined, and the succession was sampled for U/Th analysis. Travertine formation was found to occur from 542-29.7 ka, with two different tufa formation periods: from 29.7-5.8 ka and 5.8-2.08 ka. Pauses in travertine formation (palaeosols) were identified from 510-470 ka, 289-269 ka and 91-34 ka. Our study showed that climate parameters affected the formation of tufa, while the Edremit travertines developed under the control of tectonism. The Van Fault is directly associated with travertine development and its age was identified as 542 ka or older. Since the Gurpinar Fault, one of the most important faults in the region, is effective in shaping the southern slope of the travertines and limiting the movement of the Van Fault, its age should be younger than 542.4 ka. The Elmalik Fault played an active role in the formation of the Edremit tufas and is proposed to be 29.7 ka in age, from stratigraphic relationships in the region.