Ultrafiltration by a compacted clay membrane—I. Oxygen and hydrogen isotopic fractionation,☆☆

https://doi.org/10.1016/0016-7037(73)90105-1Get rights and content

Abstract

Laboratory experiments were carried out to determine the magnitude of the isotopic fractionation of distilled water and of 0.01 N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disc compacted to a porosity of 35 per cent by a pressure of 330 bars. The ultrafiltrates in both experiments were depleted in D by 2.5%. and in O18 by 0.8%. relative to the residual solution. No additional isotopic fractionation due to a salt filtering mechanism was observed at NaCl concentrations up to 0.01 N. Adsorption is most likely the principal mechanism which produces isotopic fractionation, but molecular diffusion may play a minor role.

The results suggest that oxygen and hydrogen isotopic fractionation of ground water during passage through compacted clayey sediments should be a common occurrence, in accord with published interpretations of isotopic data from the Illinois and Alberta basins.

References (24)

  • J.D. Bredehoeft et al.

    On the maintenance of anomalous fluid pressures, I. Thick sedimentary sequences

    Bull. Geol. Soc. Amer.

    (1968)
  • G.V. Chilingar et al.

    Relationship between pressure and moisture content of kaolinite, illite, and montmorillonite clays

    Bull. Amer. Assoc. Petrol. Geol.

    (1960)
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    Publication authorized by the Director U.S. Geological Survey.

    ☆☆

    Contribution 73-5 of the Institute of Geophysics and Planetary Physics, University of California at Riverside.

    Now at the Institute of Geophysics and Planetary Physics, University of California, Riverside, California 92502.

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