Stable isotopes in water from Taftan volcanic Mount

Category Petrology
Group GSI.IR
Location 23th symposium on geosciences
Holding Date 05 May 2008

      Taftan stratovolcano is located about 100 km south-southeast of Zahedan in Sistan and Baluchestan province. This Quaternary stratovolcano mainly composed of pyroclastic deposits and andesitic, dacitic and rhyolitic lava flows. These rocks locally were extensively altered by hydrothermal waters. The Taftan volcano is now in a very active fumaroles stage. At the main summit and some flanks of the volcano there are many active fumaroles vents and a few hot springs. Gas emissions and fumaroles, warm springs and extensive alteration zones in Taftan volcano are indicative of an active geothermal field and economic mineralization. Four samples from warm springs and river waters in the volcano were analyzed in Japan to determine their stable isotopes and chemical composition. ??D and ?18O values of the river waters are ?30.0 and ?35.0 per mil and??5.4 and ?6.4 per mil, respectively. ??D and ?18O values of the warm springs are ?25.0 and ?26.0 per mil and??2.0 and ?2.0 per mil, respectively. ??D and ?18O values of the river waters almost fall on MWL while??D and ?18O values of the warm springs are haveir and show shift from MWL. Our studies show that higher values of ?D and ?18O in the warm springs in the Taftan volcano are due to subsurface evaporation.