The evolution of travertine masses in the Sivas area (Central Turkey) and their relationships to active tectonics
Sicak Cermik, Delikkaya and Sarikaya are important travertine fields with active hot springs located 31 km west of Sivas. Based on their morphology, most of the travertines are classified as fissure-ridge travertines. Eroded sheet-type, terraced, and self-built channel types of travertine are also present at a few locations. Faults and fissures formed in the underlying incesu Formation, and fissures developing in the fissure-ridge travertines are linked to one another. Tectonic deformation forming the fissure-ridge travertines resulted from NE-SW extension associated with a NW-SE compressional regime related to the Central Anatolian Thrust Belt and Sivas Backthrust. U/Th series age dating results indicate that the travertine deposition extends back to 400 ka and yields ages of 11.400 (+/- 500) to 364.000 ((+201.000)/(-76.000)) from the fissure-ridge travertines. Age data and fissure width observations indicate that a similar to 0.06 mm/year extension rate is associated with the compressional regime in the Sivas Basin. On average, fissure-ridge travertines formed over intervals of 56.000 years, and indicate that a major regional seismic event with a magnitude of 7.4 has occurred here with this order of frequency. The Pamukkale travertines in Western Turkey are one of the most spectacular natural heritage sites in the world, as well as a site of active tectonic studies, and are now protected for these reasons. As shown by this study, the Sicak Cermik travertines are of comparable interest and should receive similar protection.