Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

Heiken, G.; Bevier, Mary Lou

doi:10.2172/59097

Cited by 18 publications

(24 citation statements)

References 4 publications

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“…Detailed analyses are in Tables II, III, The original analyses of J-13 were strictly qualitative, obtained with a Debye-Scherrer x-ray powder diffraction camera, scanning electron microscope, and electron microprobe (Heiken and Bevier 1979). The present analyses reveal the presence of smectite in most J-13 cores analyzed, up to 20% in J13-1575 (480.1 m), whereas the original study did not identify smectite in any samples.…”

Section: Mineral Distributions In Drill Holes J-13 Ue-26a#1 Anmentioning

confidence: 54%

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Mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 at Yucca Mountain, Nevada

Bish¹

1986

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The mineralogy of drill holes J-13, UE-25A#1, and USW G-l was previously determined using qualitative and semiquantitative techniques, and most of the available data were neither complete nor accurate. New quantitative x-ray diffraction data were obtained for rocks from all three of these drill holes at Yucca Mountain, Nevada. These quantitative analyses employed both external and internal standard x-ray powder diffraction methods and permitted the precise determination of all phasei commonly found in the tuffs at Yucca Mountain, including glass and opal-GT.These new data supplant previous analyses and include numerous additional phases. New findings of particular importance include better constraints on the distribution of the more soluble silica polymorphs, cristobalite and opal-CT. Opal-CT was associated solely with clinoptilolite-bearing horizons, and cristobalite disaopearance coincided with the appearance of analcime in USW G-l. Unlike previous analyses, we identified significant amounts of smectite in drill hole J-13. We found no evidence to support previous reports of the occurrence of erionite or phillipsite in these drill holes.

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Section: Mineral Distributions In Drill Holes J-13 Ue-26a#1 Anmentioning

confidence: 54%

“…These are minerals that are potentially important in affecting the Eh-pH conditions of groundwater. Heiken and Bevier (1979) reported the occurrence of phillipsite and erionite in several samples of J-13 core, based upon electron microprobe data and an XRO identification listed as "erionite(?). "…”

Section: Fig 4 Graphical Representation Of the Data Inmentioning

confidence: 99%

Mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 at Yucca Mountain, Nevada

Bish¹

1986

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“…1979), we have found no evidence for the presence of these two zeolites in these samples. Heiken and Bevier (1979) reported erionite in samples JA-15, JA-32, and JA-33BC and phillipsite in JA-13 all from Drill Hole J-13. These analyses were based primarily on electron microprobe data, although the discussion of JA-32 included an XRD identification they list as "erionite(?)."…”

Section: Clinoptiloiite and Mordenitementioning

confidence: 93%

“…Phillipsite ?nd Erionite Although phillipsite and erionite were previously reported to occur in several samples from both UE25a#l and J-13 (Heiken and Bevier 1979;Sykes et al . 1979), we have found no evidence for the presence of these two zeolites in these samples.…”

Section: Clinoptiloiite and Mordenitementioning

confidence: 94%

Mineralogic summary of Yucca Mountain, Nevada

Bish¹,

Vaniman²

1985

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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 mappa_,e, but only below the densely welded devitrified part of the Topopah Spring 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.

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“…Los Alamos National Laboratory staff have worked to characterize and to understand the mineralogy and petrology of the rocks at and surrounding Yucca Mountain (Heiken and Bevier 1979;Sykes et al 1979;Bish 1981;Bish et al 1981;Caporuscio et al 1982;Vaniman et al 1984;Bish and Vaniman 1985). Bish and Chipera (1989) is the most complete and recent summary of the mineralogy of Yucca Mountain rocks obtained through quantitative X-ray powder diffraction analyses of drill core and cuttings.…”

Section: Introductionmentioning

confidence: 99%

Distribution of potentially hazardous phases in the subsurface at Yucca Mountain, Nevada

Guthrie¹,

Bish²,

Raymond³

1995

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Los Alamos ABSTRACTDrilling, trenching, excavation of the Exploratory Studies Facility, and other surface-and underground-distributing activities have the potential to release minerals into the environment from tuffs at Yucca Mountain, Nevada. Some of these minerals may be potential respiratory health hazards. Therefore, an understanding of the distribution of the minerals that may potentially be liberated during site-characterization and operation of the potential repository is crucial to ensuring worker and public safety. Analysis of previously reported mineralogy of Yucca Mountain tuffs using data and criteria from the International Agency for Research on Cancer (IARC) suggests that the following minerals are of potential concern: quartz, cristobalite, tridymite, opal-CT, erionite, mordenite, and palygorskite. We have re-evaluated the three-dimensional mineral distribution at Yucca Mountain above the static water level both in bulk-rock samples and in fractures, using quantitative X-ray powder diffraction analysis. Erionite, mordenite, and palygorskite occur primarily in fractures; the crystalline-silica minerals, quartz, cristobalite, and tridymite are major bulk-rock phases. Erionite occurs in the altered zone just above the lower Topopah Spring Member vitrophyre, and an occurrence below the vitrophyre but above the Calico Hills has recently been identified. In this latter occurrence, erionite is present in the matrix at levels up to 35 wt%. Mordenite and palygorskite occur throughout the vadose zone nearly to the surface. Opal-CT is limited to zeolitic horizons.

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Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

Cited by 18 publications

References 4 publications

Mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 at Yucca Mountain, Nevada

Mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 at Yucca Mountain, Nevada

Mineralogic summary of Yucca Mountain, Nevada

Distribution of potentially hazardous phases in the subsurface at Yucca Mountain, Nevada

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