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Radiation-Enhanced Aqueous Dissolution of Minerals

Published online by Cambridge University Press:  03 March 2011

Catherine A. Dukes
Affiliation:
Laboratory for Atomic and Surface Physics, University of Virginia, Materials Science and Engineering, 395 McCormick Road, Charlottesville, VA 22904
Raúl A. Baragiola
Affiliation:
Laboratory for Atomic and Surface Physics, University of Virginia, Materials Science and Engineering, 395 McCormick Road, Charlottesville, VA 22904
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Abstract

Mineral samples of varying petrology, exposed to ion irradiation and subsequently immersed in water or exposed to a humid environment, show up to 60% depletion of specific surface atoms (Mg, Ca, K, and Na) — a depletion that is enhanced 26,000x compared to unirradiated surfaces. Surface depletions of irradiated minerals exposed to water were measured using X-ray photoelectron spectroscopy. Irradiations were performed with 4 keV Ar+ ions at fluences from 1014 – 1019 ion cm-2; samples were subsequently exposed to liquid water or humid air (35º C and 70% RH). Analyses were done before irradiation, after irradiation, and after exposure to water, allowing identification of changes in composition due solely to ion irradiation or combined with water exposure. Before water exposure, we observe no significant change in stoichiometry of the minerals for ion fluences <1018 ions cm-2. We find incongruent depletion of 60% Mg for forsterite after exposure to humidity or three minutes (or more) water immersion. Augite undergoes reduction in the surface concentration of approximately 30% Mg, 40% Ca, and 55% Na after 1.9 x 1017 Ar cm-2 and immersion in HPLC water (pH: 6.8) for three minutes. Depth profiles of the irradiated, water exposed, minerals show that the depth of the depleted region is on the order of the ion range, ~15nm. In addition, preliminary results for albite, anorthoclase, and microcline in water show significant depletions of Na, Na and K, and K, respectively, from the mineral surface.

Type
Articles
Copyright
Copyright © Materials Research Society 2011

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References

REFERENCES

1. Cantando, E.D., Dukes, C.A., Loeffler, M.J., and Baragiola, R.A., JGR 113, E09011 (2008).Google Scholar
2. Bradley, J. P., Science 265, 925929 (1994).Google Scholar
3. Demyk, K., Carrez, Ph., Leroux, H., Cordier, P., Jones, A. P., Borg, J., Quirico, E., Rayna, P. I. and d’Hendecourt, L., Astron. Astrophys. 368, L38L41 (2001).Google Scholar
4. Toppani, A., Dukes, C.A., Baragiola, R.A., and Bradley, J.P., LPS XXXVII Abstract #2056 (2006).Google Scholar
5. Dukes, C.A., Baragiola, R.A., and McFadden, L.A., JGR 104, 18651871 (1999).Google Scholar
6. Jäger, C., Fabian, D., Schrempel, F., Dorshner, J., Henning, Th., and Wesch, W., Astron.Astrophys. 401, 5765 (2003).Google Scholar
7. Ewing, R. C., Weber, W. J. and Clinard, F. W. Jr., Prog. Nucl. Energy 29, 63 (1995).Google Scholar
8. Tamain, C., Dacheux, N., Garrido, F., Habert, A., Barré, N., Özgümüs, A., and Thomé, L., J. Nuclear Mat, Volume 358, Issues 2-3, 30 November 2006, Pages 190-201.Google Scholar
9. Casey, W.H. and Bunker, B., Leaching of mineral and glass surfaces during dissolution, in Mineral and Water Interface Geochemistry, edited by Hochella, M. F. and White, A. F. (1990) pp. 397426.Google Scholar
10. Fearn, S., McPhail, D.S., Morris, R.J.H., and Dowsett, M.G., Applied Surface Science 252, 70707073 (2006).Google Scholar
11. Lanford, W.A., Davis, K., LaMarche, P., Laursen, T., Groleau, R., and Doremus, R. H., Journal of Non-Crystalline Solids 33, 249266 (1979).Google Scholar
12. Feldmann, M. and Weissman, R., Journal of Non-Crystalline Solids 218, 205209 (1997).Google Scholar
13. Blum, A. and Lasaga, A., Nature 33, 431433 (1988).Google Scholar
14. Pokrovsky, O.S. and Schott, J., Geochim. Cosmochim.Acta 64, 33133325 (2000).Google Scholar
15. Zeigler, J.F., The Stopping and Range of Ions in Matter: SRIM-03 Program, I.B.M., Yorktown Heights, N.Y., 2003.Google Scholar