petrography and classifying of the Ghorveh-Takab road travertines by using isotopic analysis method and SEM pictures

In this study, travertines from Gorveh, Bijar and Takab area, north west of Iran, were investigated using geochemical, mineralogical and isotopic methods. The investigated travertines are classified as thermogene group and the source of CO2 in travertine springs water were determined magmatic type by analysing 18O and 13C isotopes. These travertines belong to three lithofacies namely pebbly travertine, oncoid and crystalline crust. 13C ranges from .08 to .84. A probable reason for the observed high carbon isotope content in these deposits, is the presence of algae microorganisms, that is verified by SEM images. According to XRD analysis, the dominated mineral phase in the majority of samples is Calcite while Aragonite and Fe-Oxides minerals are also abundant. Ghorveh-Takab travertines may be classified in to four groups on the basis of petrographic and SEM criteria. These include compacted, laminated, Fe-Oxides and aragonite bearing classes.