Geochemical Studies of Stable Isotopes (Carbon and Oxygen) in Mahallat Travertine Deposits (South East Arak)
Subject Areas :Keywords: Stable isotope Travertine Geochemistry Mahallat.,
Abstract :
Fresh water carbonates are different in geochemical characteristics, especially in isotopic geochemical characteristics. Stable carbon and oxygen isotopes of carbonates such as travertine is one of the most important methods of study. Mahallat area with large travertine deposits, is talented to geochemical studies. this area is located in the southeast of Arak and this is a part of central Iran structural zone. Based on stable isotope studies, there are two types of travertine: thermogene and meteogene types. Thermogene C-isotope composition range between -4 ‰ and 8 ‰. However, δ13C value for meteogene type range between -11 ‰ and 0 ‰. Mahallat area travertine C-isotope composition range between 1.69 ‰ and 9.70 ‰ which indicate thermogene type. In addition, Another way to distinguish the type of travertine, is determination of carbon dioxide source. Low values of 〖〖δ^13 C〗_( CO)〗_2 imply to thermogene type and 〖〖δ^13 C〗_( CO)〗_2 Mahallat area travertine show -8.47‰ and this confirm thermogene type for these deposits. Also, water temperature during the travertine precipitation can calculate by oxygen isotope study. The temperature in Abegarm travertine is 43°C which it is evidence for thermogene type.