Investigations on Northern Urmia-Dokhtar travertines and comparison with north Sanandaj-Sirjan travertines using 18O and 13C stable isotopes

Main Travertines of Iran are located in a NW-SE trending belt (Urmia-Dokhtar Belt), extending from Tabriz to Zahedan. Neo-tectonic activities (Plecene to now) with travertine deposits around hot springs and volcanic features can be seen along this belt. In this study, East Azerbaijan travertines (northern of Urmia-Dokhtar structural zone) is investigated and are compared with Kurdistan and West Azerbaijan travertine (northern of Sanandaj-Sirjan structural zone). The studied samples classify in thermogene category, using geochemical, mineralogical and 18O and 13C isotopes studies. Based on facies studies, northern Urmia-Dokhtar travertines fall in oncoid crystalline while Sanandaj-Sirjan travertines show oncoid, crystalline crust and pebbly facies. Using the measured δ13C values of travertine gives the δ13C of the CO2 released from the water during travertine deposition. Source of the CO2 in the water springs was crustal magmatic water. The stable isotope composition of two areas were compared with Turkey travertines and they show similar genesis, CO2 source and isotopic composition.