Abstract
The modified increment method has been applied to the calculation of oxygen isotope fractionation factors for hydroxide minerals. The results suggest the following sequence of 18O-enrichment in the common hydroxides: limonite > gibbsite > goethite > brucite > diaspore. The hydroxides are significantly enriched in 18O relative to the corresponding oxides. The sequence of 18O-enrichment in the hydroxides and oxides of trivalent cations is as follows: M(OH)3 > MO(OH) > M2O3. There are also considerable fractionations within the polymorphos of Al(OH)3. The internally consistent fractionation factors for hydroxide–water systems are obtained for the temperature range of 0 to 1200 °C, which are comparable with the data derived from synthesis experiments and natural samples at surficial temperatures. Temperature dependence of oxygen isotope fractionations between goethite, gibbsite, boehmite and diaspore and water are significant enough for the purpose of geothermometry. Thus the hydroxide–water pairs hold great promise of serving as reliable paleothermometers in surficial geological environments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
