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Isothermal Diffusion of Eu And Th in Deep-Sea Sediments: Experimental Results and a Numerical Model

Published online by Cambridge University Press:  02 April 2024

Gerald B. Epstein  and
G. Ross Heath
Gerald B. Epstein
Affiliation:
Graduate School of Oceanography, University of Rhode Island, Kingston, Rhode Island 02882
G. Ross Heath
Affiliation:
College of Ocean and Fishery Sciences HA-40, University of Washington, Seattle, Washington 98195
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Abstract

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Batch data for the sorption of Eu and Th on pelagic sediments may be represented by equations of the form: ln M = A ln Cs + B/T + D, where M = concentration of sorbate on sediment, Cs = concentration of sorbate in solution, T = absolute temperature, and A, B, and D = constants. Thermodynamic interpretation of this equation leads to an expression for the true thermodynamic equilibrium constant of K = m/CsA and for the enthalpy change, ΔH, of d ln(M/CsA)/d(1/T) = −ΔH/R, where R = universal gas constant.

Experimentally, the sorption of Eu onto clay-rich sediments was very rapid in the first few seconds and slowed over an interval of minutes to hours. Rate curves were similar in shape to those of α-iron hydroxide, rather than of the oxalate-extracted residual sediment, indicating the importance of oxyhydroxide-like phases in the uptake of Eu onto red-clay sediments. For clay-rich sediments, numerical modeling reproduced the general features of a series of diffusion experiments. To a first approximation, the penetration of Eu into a sediment proceeded by saturation of the sediment to the depth of penetration and produced a sharp drop-off in sorbed + dissolved Eu concentration at the diffusion front. Higher partition coefficients (Kp) resulted in greater sorbed + dissolved concentrations, but reduced penetration. For calcareous sediments, however, Eu concentrations at the surface were much higher than at depth, presumably due to the formation of an insoluble carbonate.

Keywords

Deep-sea sedimentsDiffusionEuropiumPartition coefficientSorptionThorium
Type
Research Article
Information
Clays and Clay Minerals , Volume 34 , Issue 3 , June 1986 , pp. 295 - 306
Copyright
Copyright © 1986, The Clay Minerals Society

References

Corliss, B. H., Hollister, C. D., Von Herzen, B., Richardson, M. J., Dow, W., Heath, G. R., Laine, E. P., Prince, R., Epstein, G. B., Leinen, M., Doyle, P., Riedel, W., McDuff, R., Silva, A., Calnan, D., Baldwin, K., Hayes, D., Tucholke, B. E., Taft, B., Scrutton, R. A. and Talwani, M., 1982 A paleoenvironmental model for Cenozoic sedimentation in the central North Pacific The Ocean Floor New York Wiley 277–304.Google Scholar
Doyle, P. S. and Riedel, W.R., 1979 Cretaceous to Neogene ichthyoliths in a giant piston core from the central North Pacific Micropaleontology 25 337–364.CrossRefGoogle Scholar
Duursma, E. K. and Hoede, C., 1967 Theoretical, experimental and field studies concerning molecular diffusion of radioisotopes in sediments and suspended solid particles of the sea. Part A. Theories and mathematical calculations Netherlands J. Sea Res. 3 423–457.CrossRefGoogle Scholar
Glasstone, S., 1946 Textbook of Physical Chemistry 2nd New York Van Nostrand Co. 1047–1048.Google Scholar
Hayward, D. O. and Trapnell, B. M. W., 1964 Chemisorption 2nd Washington, D.C. Buttersworth 159–225.Google Scholar
Heath, G. R., Epstein, G. B., Leinen, M., Prince, R. A. and Talbert, D. M., 1977 Geochemical and sedimentological assessment of deep-sea sediments Seabed Disposal Program Annual Report, January-December 1976 New Mexico Sandia Laboratories, Albuquerque 53–144.Google Scholar
Heath, G. R., Epstein, G. B., Leinen, M., Prince, R. A. and Talbert, D. M., 1978 Geochemical and sedimentological assessment of deep-sea sediments Seabed Disposal Program Annual Report, January-December 1977 New Mexico Sandia Laboratories, Albuquerque 33–188.Google Scholar
Heath, G. R., Laine, E. P., Heggie, D., Epstein, G. B., Leinen, M., Prince, R. A. and Talbert, D. M., 1979 Geochemical and sedimentological assessment of deep-sea sediments Seabed Disposal Program Annual Report, January-December 1978 Albuquerque Sandia Laboratories 121–236.Google Scholar
Heath, G. R. and Pisias, N. G., 1979 A method for the quantitative estimation of clay minerals in North Pacific deep-sea sediments Clays & Clay Minerals 27 175–184.CrossRefGoogle Scholar
Kolthoff, I. M. and Sandell, E. B., 1946 Textbook of Quantitative Inorganic Analysis New York Macmillan 471–473.Google Scholar
Laudelout, H. R., Van Bladel, H. R., Bolt, G. H. and Page, A. L., 1968 Thermodynamics of heterovalent cation exchange reactions in a montmorillonite clay Trans. Faraday Soc. 64 1477–1488.CrossRefGoogle Scholar
Leinen, M. and Heath, G. R., 1981 Sedimentary indicators of atmospheric activity in the northern hemisphere during the Cenozoic Palaeogeog. Palaeoclimatol. Palaeoecol. 36 1–21.CrossRefGoogle Scholar
Li, Y.-H. and Gregory, S., 1974 Diffusion of ions in sea water and in deep-sea sediments Geochim. Cosmochim. Acta 38 703–714.Google Scholar
Manheim, F. T., 1970 The diffusion of ions in unconsolidated sediments Earth Planet. Sci. Lett. 9 307–309.CrossRefGoogle Scholar
McBride, M. B., 1980 Interpretation of the variability of selectivity coefficients for exchange between ions of unequal charge on smectites Clays & Clay Minerals 28 255–261.CrossRefGoogle Scholar
Palmer, J. and Bauer, N., 1961 Sorption of amines by montmorillonite J. Phys. Chem. 65 894–895.CrossRefGoogle Scholar
Prince, R. A., Heath, G. R. and Kominz, M., 1980 Paleomagnetic studies of central North Pacific sediment cores: stratigraphy, sedimentation rates, and the origin of magnetic instability Geol. Soc. Amer. Bull. 91 1789–1835.CrossRefGoogle Scholar
Roache, P. J., 1972 Computational Fluid Dynamics New Mexico Hermosa Publishers, Albuquerque 18–22.Google Scholar
Rodden, C.J., 1950 Analytical Chemistry of the Manhattan Project New York McGraw-Hill 170–171.Google Scholar