Abstract
Predicting the behaviour of radioactive wastes can be facilitated by comparison with the evolution of natural groundwater systems. During a study of the Kanamaru U mineralization (Japan), geochemical approaches for understanding a shallow (0-50 m) fresh groundwater flow system are being assessed. Deep granitic waters are Ca-HCO3-dominated and slightly acidic to slightly alkaline. Shallow waters within sediments display lower pH and they are more dilute. Halide concentrations suggest the existence of a non marine Br-rich and Cl-depleted deep groundwater in the basement. 234U/238U and 230Th/234U activity ratios in the mineralized sedimentary rocks indicate that U mobilization took place within the last 350,000 years. U dissolution currently continues and it is controled by lateral groundwater flow whereas vertical diffusion appears negligible. Dissolved alkaline earths concentrations and the 87Sr/86Sr ratio indicate that solutes exchanges take place through uppermost low permeable granite followed by mixing with more dilute and Cl-type shallow groundwater.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
R. Bros, H. Hidaka, G. Kamei, T. Ohnuki, Applied Geochem., 18, 1807 (2003).
R. Metcalfe, K. Hama, K. Amano, T. Iwatsuki, H. Saegusa, proceed. Int. Symp. Groundwater Problems related to Geo-environment, Okayama, Japan, pp. 28–30 (2003).
Y. Watanabe, Y. Seki, K. Naito, M. Zhang, M. Suzuki, M. Takeda, and A. Kamei, Geol. Soc. America Annual meeting proceed., 242–21 (2004).
Y. Seki, K. Naito, A. Kamei, H. Tsukamoto, and Y. Watanabe, Geol. Soc. America Meeting, Denver, 242–19 (2004).
Y. Seki, K. Naito, A. Kamei, K. Okuzawa, M. Zhang, and Y. Watanabe, proceed. Conf. on energy, environment and disasters (INCEED), E. 6-457 (2005).
Y. Seki, K. Naito, A. Kamei, K. Okuzawa, N. Takeno, and Y. Watanabe, Geol. Soc. America, special publication, submitted (2005).
J. D. Hanor J. D., in Geofluids: origin, migration and evolution of fluids in sedimentary basins, edited by J. S. Parnell, (Geol. Soc. London, 78, 1994), pp. 151–174.
J. K. Osmond, J. B. Cowart, and M. Ivanovitch, J. Appl. Rad. Isot. 34, 283 (1983).
J. R. Bargar, R. Reitmeyer, J. J. Lenhart, J. A. Davis, Geochim. Acta. 64, 2737 (2000).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bros, R., Seki, Y., Kamei, A. et al. Geochemical Approaches to Understanding a Shallow Groundwater Flow in the Kanamaru Uranium Mineralization Area (Japan). MRS Online Proceedings Library 893, 8930907 (2005). https://doi.org/10.1557/PROC-0893-JJ09-07
Received:
Accepted:
Published:
DOI: https://doi.org/10.1557/PROC-0893-JJ09-07