Stable Isotope-Enabled Hydrogeochemistry
The interaction of water and mineral surfaces can be studied using the stable isotopes of hydrogen and oxygen in water. We are making advances in techniques to study these interactions and their stable isotope dynamics.
The interaction of water and mineral surfaces can be studied using the stable isotopes of hydrogen and oxygen in water. We are making advances in techniques to study these interactions and their stable isotope dynamics.
Oxygen isotope fractionation effects in soil water
via interaction with soil mineral particles
The relationship of shifts in the 18O composition of soil water in mixtures of Mg-, Ca-, K-, Na-treated montmorillonite and water to gravimetric water content (Oerter et al., 2014, Journal of Hydrology).
In isotope-enabled approaches to hydrology, the soil matrix is typically assumed to be inert with respect to the water oxygen isotopes in the system. We show that Mg, and Ca ions adsorbed to clay minerals exert an effect on the water molecules nearby that tends to concentrate the H2O molecules with an 18O atom around each metal ion, while K ions tend to attract 16O. Our report is the first observation and quantification of this effect and raises the notion that this effect may be present in natural soils that have high clay contents and high cation concentrations. This effect may be a mechanism to explain unusual soil water isotope and ecohydrologic behavior observed in many instances.
Oerter, E, K Finstad, J Schaeffer, G Goldsmith, T Dawson, R Amundson, 2014, Oxygen isotope fractionation effects in soil water via interaction with cations (Mg, Ca, Na, K) adsorbed to phyllosilicate clay minerals. Journal of Hydrology, v. 515, p. 1-9. pdf pdfdf
Hydrogen and oxygen stable isotope dynamics of
hyper-saline and salt-saturated aqueous solutions
Oerter, E, M Singleton, L Davisson, 2018, Hydrogen and oxygen stable isotope dynamics of hyper-saline and salt-saturated aqueous solutions, Geochimica et Cosmochimica Acta, v. 238, p. 316-328.
Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy
Oerter, E, M Singleton, L Davisson, 2017, Hydrogen and oxygen stable isotope signatures of goethite hydration waters by thermogravimetry-enabled laser spectroscopy. Chemical Geology, v. 475, p. 14-23