Oxygen and Carbon Isotope Fractionation Study of Coexisting Limestones

Department of Chemistry, Patna University, Patna-5, Department of Chemistry, Bihar University, Muzaffarpur Manuscript received 11 April 1975; accepted 15 July 1975. Investigation of limestone samples has been made with a view to study O18 and C13 fractiona­tion. The isotopic fractionation between dolomite and calcite are in the range —0.23 to 0.95 for oxygen and —1.49 to 1.13 for carbon. The variation in ∆O18 and ∆C13 have been explained as due to the formation of dolomite from the calcite precursor by the combination of both solid state cation exchange (metasomatic) and dissolution processes under isotopic non-equilibrium