title: (18)O/(16)O and (13)c/(12)c fractionation during the reaction of carbonates with phosphoric Acid: effects of cationic substitution and reaction temperature.
abstract: Abstract   The factors for (18)O/(16)O fractionation between carbonates and CO(2) gas produced by the dissolution of the carbonates in phosphoric acid (sealed vessel method) have been investigated as a function of reaction temperature (20-90°C) and cationic substitution in the solid. Synthetic CaCO(3), Ca(0.75) Mn(0.25) CO(3), MnCO(3), BaCO(3) and SrCO(3) powders, and a natural kutnahorite sample were used as solids. The δ(18)O values of the gaseous CO(2) liberated by the reaction with phosphoric acid decrease with increasing temperature and seem to be a linear function of T(°K)(-2). The slopes are specific for different carbonates. No temperature-depended (13)C/(12)C fractionation seems to exist.
authors.affiliation: a    Institute of Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University   ,  Oldenburg ,    Germany.
authors.forename: M E
authors.initials: ME
authors.lastname: Böttcher