Meheut M., Lazzeri M., Balan Etienne, Mauri F. (2007). Equilibrium isotopic fractionation in the kaolinite, quartz, water system : Prediction from first-principles density-functional theory. Geochimica et Cosmochimica Acta, 71 (13), p. 3170-3181. ISSN 0016-7037.
Titre du document
Equilibrium isotopic fractionation in the kaolinite, quartz, water system : Prediction from first-principles density-functional theory
Geochimica et Cosmochimica Acta, 2007,
71 (13), p. 3170-3181 ISSN 0016-7037
Isotopic fractionation factors for oxygen, hydrogen and silicon have been calculated using first-principles methods for the kaolinite, quartz, water (ice and gas water) system. Good agreement between theory and experiment is obtained for mineral-water oxygen isotope fractionation. This approach gives reliable results on isotopic fractionation factors as a function of temperature, within a relative precision of typically 5%. These calculations provide independent quantitative constraints on the internal fractionation of oxygen in kaolinite, the fractionation of silicon isotopes at equilibrium, or hydrogen fractionation between kaolinite and water. Calculated fractionation factors at 300 K are 12.5 parts per thousand for the kaolinite internal-fractionation of oxygen, and 1.6 parts per thousand for silicon fractionation between quartz and kaolinite.
