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Uraninite-Water Interactions in an OxidizingEnvironment

Published online by Cambridge University Press:  03 September 2012

M. Fayek ,
T. K. Kyser ,
R. C. Ewing  and
M. L. Miller
M. Fayek
Affiliation:
Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA 87131, fayek@unm.edu, rewing@unm.edu, mmiller@unm.edu
T. K. Kyser
Affiliation:
Department of Geological Sciences, Queen's University, Kingston, Ontario, Canada, K7L 3N6, kyser@Geol.QueensU.ca
R. C. Ewing
Affiliation:
Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA 87131, fayek@unm.edu, rewing@unm.edu, mmiller@unm.edu
M. L. Miller
Affiliation:
Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, USA 87131, fayek@unm.edu, rewing@unm.edu, mmiller@unm.edu
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Abstract

Exceptionally low δ 18O values of primary uraninite andpitchblende (i.e. -32 per mil to -19.5 per mil) from Proterozoicunconformity-type uranium deposits in Saskatchewan, Canada, in conjunctionwith theoretical uraninite-water oxygen isotope fractionation factorssuggest that primary uranium mineralization is not in oxygen isotopieequilibrium with clays and silicates. The low δ 18O values havebeen interpreted to have resulted from the recrystallization of primaryuranium mineralization in the presence of modern meteoric fluids having lowδ 18O values of ca. -18 per mil. The absence of apparentalteration in many of the uraninite and pitchblende samples requires thatthe uranium minerals exchange oxygen isotopes with fluids, with only minordisturbances to their original chemical compositions and textures. However,experiments on the interaction between water and natural uraninites, fromthese deposits, and detailed electron micro-probe analyses of naturaluraninite and pitchblende indicate that, in the presence of water, olduraninite rapidly alters to curite (Pb2U5O174H2O). The hydrationof uraninite to curite releases uranium and calcium into solution andbecquerelite (Ca(UO2)6O4(OH)6H2O)is precipitated. In the presence of Si-saturated waters, uranium silicateminerals, soddyite ((UO2)2(SiO4)2H2O) andkasolite (Pb(UO2)SiO4H2O are precipitatedin addition to, curite and schoepite ((UO2)8O2(OH)12(H2O)12).The mineral paragenesis observed in these experiments is similar tosequences observed in oxidized zones in uranium deposits andUO2-water experiments. Therefore, it is unlikely that naturaluraninite and pitchblende can simply exchange oxygen with an oxidizing fluidwithout a concomitant change in phase chemistry or structure, nor willoxidation of uraninite lead to the formation of U3O7.as predicted by theoretical calculations used in natural analogue studiesfor the disposal of high level nuclear waste.

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Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 465: Symposium II – Scienfific Basis for Nuclear Waste Management XX , 1996 , 1201
Copyright
Copyright © Materials Research Society 1997

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References

REFERENCES

1. Finch, R.J. and Ewing, R.C., J. Nucl. Mater., 190, p. 133–156 (1992).Google Scholar
2. Janeczek, J., Ewing, R.C., Oversby, V.M. and Werme, L.O., J. Nucl. Mater., in press (1996).Google Scholar
3. Hattori, K. and Halas, S., Geochim. Cosmochim. Acta, 46, p. 1863–1868 (1982).Google Scholar
4. Hoekstra, H.R. and Katz, J.J., U.S. Geological Survey Professional Paper 300, p. 543–547 (1956).Google Scholar
5. Hattori, K., Muehlenbachs, K., and Morton, D., Geol. Soc. Amer.-Geol. Soc. Can., Pgm. w Abst, 10, A417 (1978).Google Scholar
6. Kotzer, T.G. and Kyser, T.K., Am. Mineral., 78, p. 1262–1274 (1993).Google Scholar
7. Fayek, M. and Kyser, T.K., accepted, Can. Min (1996).Google Scholar
8. Zheng, Y., Geochim. Cosmochim. Acta., 55, p. 2299–2307 (1991).Google Scholar
9. Wilson, M.R. and Kyser, T.K., Econ. Geol., 82, p. 1450–1557 (1987).Google Scholar
10. Kotzer, T.G. and Kyser, T.K., Sask. Energy and Mines, Sask. Geol. Surv., Misc. Rep. 90–4, p. 153–157 (1990).Google Scholar
11. Kotzer, T.G. and Kyser, T.K., Chern. Geol., 120, p. 45–89 (1995).Google Scholar
12. Janeczek, J., Ewing, R.C. and Thomas, L.E., J. Nucl. Mater., 207, p. 177–191 (1993).Google Scholar
13. Cramer, J.J. and Smellie, J.A.T., AECL Rep. 10851 (1994).Google Scholar
14. Cramer, J.J., AECL Rep. 11204 (1995).Google Scholar
15. Smellie, J.A.T. and Karlsson, F., SKB Tech. Rep. TR 96–08, (1996).Google Scholar
16. Bowles, J.F.W., Chem. Geol., 83, p. 47–53 (1990).Google Scholar
17. Wronkiewicz, D.J., Bates, J.K., Gerding, T.J., Veleckis, E. and Tani, B.S., J. Nucl. Mater., 190, p. 107–127 (1992).Google Scholar
18. Grandstaff, D.E., Econ. Geol., 71, p. 1493–1506 (1976).Google Scholar
19. Gronvold, F., J. Inorg. Nucl. Chem., 1, p. 357–370 (1955).Google Scholar
20. Berman, R.M., Journal of the Mineralogical Society of America, 42, p. 705–731 (1957).Google Scholar
21. Powers, L. and Stauffer, M., Can. J. Earth Sci., 25, p 1945–1954 (1985).Google Scholar
22. Janeczek, J. and Ewing, R.C., R.C., J. Nucl. Mater., 190, p. 128–132 (1992).Google Scholar
23. O'Neil, J.R., Stable Isotopes in High Temperature Geological Processes, eds. Valley, J. W., Taylor, H.P., O'Neil, J.R. (Reviews in Mineralogy, 16, Mineral. Soc. of Amer, 1986), p. 1–37.Google Scholar
24. Kieffer, S.W., Rev. Geophys. Space Phys., 30–4, p. 827–849 (1982).Google Scholar
25. Becker, R.H. and Clayton, R.N., Geochim. Cosmochim. Acta, 40, p. 1151–1165 (1976).Google Scholar