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Alteration History Studies in the Exploratory Studies Facility, Yucca Mountain, Nevada, USA

Published online by Cambridge University Press:  15 February 2011

S. S. Levy ,
D. I. Norman  and
S. J. Chipera
S. S. Levy
Affiliation:
Earth and Environmental Sciences Division, Mail Stop D462, Los Alamos National Laboratory, Los Alamos, NM 87545, sslevy@lanl.gov
D. I. Norman
Affiliation:
Department of Geoscience, New Mexico Tech, Socorro, NM 87801
S. J. Chipera
Affiliation:
Earth and Environmental Sciences Division, Mail Stop D462, Los Alamos National Laboratory, Los Alamos, NM 87545, sslevy@lanl.gov
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Abstract

By mid-1995, the Exploratory Studies Facility (ESF) extended about 1.1 km from Exile Hill westward toward Yucca Mountain, mostly within densely welded, devitrified Tiva Canyon Tuff. Secondary mineral occurrences in this unit include breccia cements of mordenite, a fibrous zeolite, and vapor-phase deposits of silica, alkali feldspar, apatite, hollandite, amphibole, and zircon. Calcite is also a common secondary mineral in faults and fractures. Studies of water and gas contents in fluid inclusions in calcites from a fault in nonwelded tuff and a fracture in densely welded tuff suggest mineral deposition under transient locally saturated conditions. Calcite in the nonwelded tuff incorporated air from the unsaturated tuff adjacent to the fault.

A highly altered interval within pre-Pah Canyon tuffs just above the top of the Topopah Spring Tuff may be a fossil fumarole or other hydrothermal feature associated with cooling pyroclastic deposits, overprinted by later zeolitic alteration. The observed quartz, cristobalite, opal-CT, and fluorite have been widely identified as products of syngenetic devitrification and vapor-phase alteration in and above the Topopah Spring Tuff. Smectite, also an abundant secondary mineral at the ESF site, has been observed elsewhere at this stratigraphic level.

Zeolitic alteration of nonwelded tuffs above the Topopah Spring Tuff, as seen in the ESF, has also been noted in drill core and outcrop at northeastern Yucca Mountain. The hydrologic and geochemical conditions that favored zeolitization only in certain areas of this stratigraphic interval have yet to be determined.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 412: Symposium V – Scientific Basis for Nuclear Waste Management XIX , 1995 , 783
Copyright
Copyright © Materials Research Society 1996

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References

1. Sandia National Laboratories, “Administrative Ramp Cross Section: Lithology and Borehole Projections,” Drawing No. 88-60-09, Version QA1.7 (1994).Google Scholar
2. Chung, F., Journal of Applied Crystallography 7, p. 519 (1974).Google Scholar
3. Chipera, S. and Bish, D., Los Alamos National Laboratory report LA- 11663-MS (1989).Google Scholar
4. Bish, D. and Chipera, S., Clays and Clay Minerals 39, p. 437 (1991).Google Scholar
5. Gundimeda, M., “Environmental Gas Analysis of Fluid Inclusions in Calcium Carbonates from New Mexico, Including Vein Calcites from Los Alamos National Laboratory, Using Quadrupole Mass Spectrometry,” MS Thesis, New Mexico Tech., Socorro, NM, 141 pp. (1995).Google Scholar
6. Newman, B., Norman, D., Gundimeda, M., and Levy, S., Chem. Geology (in press).Google Scholar
7. National Research Council, Ground Water at Yucca Mountain: How High Can It Rise? National Academy Press, Washington, D. C., 231 pp. (1992).Google Scholar
8. Cowan, D., Priest, V., and Levy, S., Appl. Radiat. Isot. 44, p. 1035 (1993).Google Scholar
9. Guthrie, G. Jr., Bish, D., Chipera, S., and Raymond, R. Jr, Los Alamos National Laboratory report LA-12573-MS (1995).Google Scholar
10. Levy, S., in Scientific Basis for Nuclear Waste Management XVI, edited by Interrante, C. and Pabalan, R. (Mater. Res. Soc. Symp. Proc. 294, Pittsburgh, PA 1993), p. 543–548.Google Scholar
11. Carr, W., U.S. Geol. Survey Open-File Report 82–457 (1982).Google Scholar
12. Broxton, D., Vaniman, D., Caporuscio, F., Arney, B., and Heiken, G., Los Alamos National Laboratory report LA-9324-MS (1982).Google Scholar
13. Broxton, D., Chipera, S., Byers, F. Jr., and Rautman, C., Los Alamos National Laboratory report LA-12542-MS (1993).Google Scholar