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Title: Mineralogic summary of Yucca Mountain, Nevada

Abstract

Quantitative x-ray powder diffraction analysis of tuffs and silicic lavas, using matrix-flushing techniques, has been used to obtain a model of three-dimensional mineral distributions at Yucca Mountain, Nevada. This method of analysis is especially useful in tuff, where the most abundant phases are commonly too fine grained for optical determination. The three-dimensional distributions of primary glass and of tridymite are particularly well constrained. Vitric nonwelded glasses occur above and below the welded devitrified Topopah Spring Member, but the glass in the lower nonwelded vitric zone is progressively altered to zeolites to the east where the zone is closer to the static water level. The zeolites clinoptilolite, mordenite, heulandite, and erionite have all been found at Yucca Mountain, but only mordenite and clinoptilolite are abundant and can be mapped between many drill holes and at many depths. Heulandite distribution is also mappable, but only below the densely welded devitrified part of the Topopah Storing Member. Erionite has been confirmed only once, as a fracture coating. There is a fairly continuous smectite-rich interval immediately above the basal vitrophyre of the Topopah Spring Member, but no evidence suggests that the smectites can provide information on the paleogroundwater table. There are at least fourmore » mappable zeolitized zones in Yucca Mountain, and the thicker zones tend to coincide with intervals that retained glass following early tuff devitrification. Problems in extrapolation occur where zones of welding pinch out. No phillipsite has been found, and some samples previously reported to contain phillipsite or erionite were reexamined with negative results. The deeper alteration to albite and analcime was not sampled in every drill hole, and the distribution of these phases is difficult to map.« less

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
59793
Report Number(s):
LA-10543-MS
ON: DE86007579
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Oct 1985
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 05 NUCLEAR FUELS; YUCCA MOUNTAIN; TUFF; MINERALOGY; X-RAY DIFFRACTION; GLASS; SMECTITE; CLINOPTILOLITE; MORDENITE; Yucca Mountain Project

Citation Formats

Bish, D L, and Vaniman, D T. Mineralogic summary of Yucca Mountain, Nevada. United States: N. p., 1985. Web. doi:10.2172/59793.
Bish, D L, & Vaniman, D T. Mineralogic summary of Yucca Mountain, Nevada. United States. https://doi.org/10.2172/59793
Bish, D L, and Vaniman, D T. 1985. "Mineralogic summary of Yucca Mountain, Nevada". United States. https://doi.org/10.2172/59793. https://www.osti.gov/servlets/purl/59793.
@article{osti_59793,
title = {Mineralogic summary of Yucca Mountain, Nevada},
author = {Bish, D L and Vaniman, D T},
abstractNote = {Quantitative x-ray powder diffraction analysis of tuffs and silicic lavas, using matrix-flushing techniques, has been used to obtain a model of three-dimensional mineral distributions at Yucca Mountain, Nevada. This method of analysis is especially useful in tuff, where the most abundant phases are commonly too fine grained for optical determination. The three-dimensional distributions of primary glass and of tridymite are particularly well constrained. Vitric nonwelded glasses occur above and below the welded devitrified Topopah Spring Member, but the glass in the lower nonwelded vitric zone is progressively altered to zeolites to the east where the zone is closer to the static water level. The zeolites clinoptilolite, mordenite, heulandite, and erionite have all been found at Yucca Mountain, but only mordenite and clinoptilolite are abundant and can be mapped between many drill holes and at many depths. Heulandite distribution is also mappable, but only below the densely welded devitrified part of the Topopah Storing Member. Erionite has been confirmed only once, as a fracture coating. There is a fairly continuous smectite-rich interval immediately above the basal vitrophyre of the Topopah Spring Member, but no evidence suggests that the smectites can provide information on the paleogroundwater table. There are at least four mappable zeolitized zones in Yucca Mountain, and the thicker zones tend to coincide with intervals that retained glass following early tuff devitrification. Problems in extrapolation occur where zones of welding pinch out. No phillipsite has been found, and some samples previously reported to contain phillipsite or erionite were reexamined with negative results. The deeper alteration to albite and analcime was not sampled in every drill hole, and the distribution of these phases is difficult to map.},
doi = {10.2172/59793},
url = {https://www.osti.gov/biblio/59793}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 01 00:00:00 EDT 1985},
month = {Tue Oct 01 00:00:00 EDT 1985}
}