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.