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Structure of the Tshirege Member of the Bandelier Tuff at Mesita del Buey, Technical Area 54, Los Alamos National Laboratory

Description: The geological structure of the Tshirege Member of the Bandelier Tuff at Mesita del Buey, Technical Area 54, was examined using precise surveying of the contact between tuff units Iv and 2 for 3.5 km along the north wall of Pajarito Canyon and 0.6 km along the north wall of a tributary to Caiiada del Buey. Estimated structure contours on this contact indicate typical strikes of N40E to N70E along this part of Mesita del Buey, although the apparent stfike of the tuff is E-W at the western part of the survey. Typical dips are 1.OO to 2.0o to the east or southeast, with an estimated maximum dip of 3.2o near the west end of Material Disposal AreaG. Thirty seven faults with vertical displacements of 5 to 65 cm were observedin outcrops along the Pajarito Canyon traverse, and, due to the incomplete exposure of the contact between unit lV and unit 2, many more faults of this magnitude undoubtedly exist. The faults have a wide range in strike and have either down-to-the-west or down-to-the-east components of offset, although about 65% of the observed displacement is down-to-the-west or northwest. The general absence of larger-scale offsets or inflections along the contact between units lV and 2 in areas where the small-scale faults were observed suggests that they are not associated with major fault zones. Instead, these faults may record distributed secondary deformation across the Pajarito Plateau associated with large earthquakes on the main Pajarito fault zone 8 to 11 km to the west, or perhaps earthquakes on other faults in the region. The survey data also suggest that a 150 to 250 m wide zone of greater magnitude faulting is present near the west end of the traverse associated with a horst-and-graben structure displaying about 1.5 to 3.5 m of offset on ...
Date: December 1, 1998
Creator: LaDelfe, Carol; Broxton, David E.; Carney, John S. & Reneau, Steven L.
Partner: UNT Libraries Government Documents Department

Fracture Characteristics in a Disposal Pit on Mesita del Buey, Los Alamos National Laboratory

Description: The characteristics of fractures in unit 2 of the Tshirege Member of the Bandelier Tuff were documented in Pit 39, a newly excavated 13.7 m deep disposal pit at Material Disposal Area G on Mesita del Buey. The average spacing between fractures is about 1.0 to 1.3 m, the average fracture aperture is about 3 to 5 mm, and the average fracture dip is about 76o to 77o. Fracture spacing and dip in Pit 39 are generally consistent with that reported from other fracture studies on the Pajarito Plateau, although the fracture apertures in Pit 39 are less than reported elsewhere. Measured fracture orientations are strongly affected by biases imparted by the orientations of the pit walls, which, combined with a small data set, make identification of potential preferred orientations dlfflcult. The most prominent fracture orientations observed in Pit 39, about E-W and N20E, are often not well represented elsewhere on the Pajarito Plateau. Fracture fills contain smectite to about 3 m depth, and calcite and opal may occur at all depths, principally associated with roots or root fossils (rhizoliths). Roots of pifion pine extend in fractures to the bottom of the pit along the north side, perhaps indicating a zone of preferred infiltration of water. Finely powdered tuff with clay-sized particles occurs within a number of fractures and may record abrasive disaggregation associated with small amounts of displacement on minor local faults.
Date: December 1, 1998
Creator: Vaniman, David T. & Reneau, Steven L.
Partner: UNT Libraries Government Documents Department

Core flow experiment protocol

Description: This letter report describes the current status of the core flow through apparatus and describes the protocol and test matrix to be followed during the initial experimental stage of radionuclide transport studies in the Integrated Testing task.
Date: December 1, 1997
Creator: Viani, B.E. & Martin, S.I.
Partner: UNT Libraries Government Documents Department

Report on laboratory tests of drying and re-wetting of intact rocks from the drift scale and single heater tests

Description: The primary focus of this report is the measurement of moisture retention curves of tuff as a function of temperature for both drying and re-wetting conditions. The report contains descriptions of experimental designs and procedures, data, observation, preliminary analyses, and future work. Knowledge of unsaturated transport properties is critical for understanding the movement of water through the unsaturated zone. Evaluation of the performance of a potential nuclear waste repository also depends on these properties. Moisture retention data are important input of numerical models of moisture movement in unsaturated porous media. Also important is the effect of sample history on the moisture retention curves, and whether or not there is significant hysteresis between wetting and drying measurements. This report addresses initial observations regarding this aspect of the research.
Date: January 1, 1998
Creator: Roberts, J.J.; Carlberg, E.; Pletcher, R. & Lin, W.
Partner: UNT Libraries Government Documents Department

Determination of mineral abundances in samples from the Exploratory Studies Facility, Yucca Mountain, Nevada, using x-ray diffraction

Description: Tuff samples collected from the Exploratory Studies Facility (ESF) were X-rayed to estimate relative mineral abundances. X-ray analysis was performed on sub-samples of specimens collected from both the Single Heater Test (SHT) and Drift Scale Heater Test (MT) that were used for thermomechanical measurements, as well as samples collected from cores retrieved from boreholes in the Drift Scale Test Area. The abundance of minerals that could affect the behavior of the host rock at repository relevant temperatures is of particular interest. These minerals include cristobalite, which undergoes a phase transition and volume change at elevated temperature (-250 {degree}C), and smectite and clinoptilolite that can dehydrate at elevated temperature with accompanying volume reduction. In addition, the spatial distribution of Si02 polymorphs and secondary minerals may provide evidence for deducing past fluid pathways. The mineral abundances tabulated here include data reported previously in three milestone reports but reanalyzed, as well as previously unreported data.
Date: January 13, 1998
Creator: Roberts, S. & Viani, B.
Partner: UNT Libraries Government Documents Department

Anisotropic behavior in 0.5m scale blocks of Topopah Spring tuff

Description: Laboratory tests on 0.5 meter scale blocks of Topopah Spring tuff were performed to determine fluid flow and mechanical behavior of samples containing fractures. Results include data for a comprehensive set of flow measurements through a rock sample containing a horizontally oriented fracture at uniaxial stress conditions up to 8 MPa at room temperature. Directional channeling, rather than mean fracture aperture, controls the flow. On the time scale of these experiments, inhibition is negligible.
Date: February 1, 1998
Creator: Blair, S. C. & Costantino, M. S.
Partner: UNT Libraries Government Documents Department

A Review of Degradation Behavior of Container Materials for Disposal of High-Level Nuclear Waste in Tuff and Alternative Repository Environments

Description: Corrosion resistance of materials in aqueous systems is reviewed from the perspective of their suitability as container materials for nuclear waste. A discussion of the chemistry and characterization of repository environments, namely, tuff and alternative environments (shale, limestone, and carbonate), is followed by a description of corrosion mechanisms. In this review, emphasis is placed on localized corrosion (e.g., stress corrosion cracking, crevice corrosion, and pitting) because localized corrosion is difficult to account for in design of components, but it is the life-limiting factor for many metallic and nonmetallic systems.
Date: June 1989
Creator: Maiya, P. S.
Partner: UNT Libraries Government Documents Department

Results of plug-flow reactor experiments with crushed tuff at 280C and 300C

Description: We report on the results to date for two plug-flow reactor experiments, PFR-11 and PFR-13, designed to simulate reactive transport chemical and physical processes. These experiments provide a physical model of idealized one dimensional plug flow and chemical reaction using deionized water and crushed Topopah Springs Tuff (Tsw2). Data consist of effluent ion concentrations and pH measurements taken at several times during both experiments and limited mineralogical analysis of post-test solid phases for PFR-11.
Date: September 2, 1999
Creator: Dibley, M J; Knauss, K G & Rosenberg, N D
Partner: UNT Libraries Government Documents Department

Neutron and gamma (density) logging in welded tuff

Description: This Technical Implementation Procedure (TIP) describes the field operation, and the management of data records pertaining to neutron logging and density logging in welded tuff. This procedure applies to all borehole surveys performed in support of Engineered Barrier System Field Tests (EBSFI� ), including the Earge Block Tests (LBT) and Initial Engineered Barrier System Field Tests (IEBSFT) - WBS The purpose of this TIP is to provide guidelines so that other equally trained and qualified personnel can understand how the work is performed or how to repeat the work if needed. The work will be documented by the use of Scientific Notebooks (SNs) as discussed in 033-YMP-QP 3.4. The TIP will provide a set of guidelines which the scientists will take into account in conducting the mea- surements. The use of this TIP does not imply that this is repetitive work that does not require profes- sional judgment.
Date: September 12, 1998
Creator: Lin, W.
Partner: UNT Libraries Government Documents Department

[Evolution of Sedimentary Basins--Uinta and Piceance Basins: Chapters J and K]

Description: From abstract: This is a report on reconnaissance geologic mapping and isotopic dating of tuff beds in the Uinta Basin of Utah that show that Lake Uinta probably persisted into late Eocene time in the area east of Duchesne and Strawberry Reservoir.
Date: 1989
Creator: Bryant, Bruce; Naeser, Charles W.; Marvin, Richard F. & Mehnert, H. H.
Partner: UNT Libraries Government Documents Department

Postglacial Volcanic Deposits at Mount Baker, Washington, and Potential Hazards From Future Eruptions

Description: Abstract: Eruptions and other geologic events at Mount Baker during the last 10,000 years have repeatedly affected adjacent areas, especially the valleys that head on the south and east sides of the volcano. Small volumes of tephra were erupted at least four times during the past 10,000 years. Future eruptions like these could cause as much as 35 centimeters of tephra to be deposited at sites 17 kilometers from the volcano, 15 centimeters of tephra to be deposited 29 kilometers from the volcano, and 5 centimeters, 44 kilometers from the volcano. Lava flows were erupted at least twice during the last 10,000 years and moved down two valleys. Future lava flows will not directly endanger people because lava typically moves so slowly that escape is possible. Hot pyroclastic flows evidently occurred during only one period and were confined to the Boulder Creek valley. Such flows can move at speeds of as much as 150 kilometers per hour and can bury valley floors under tens of meters of hot rock debris for at least 15 kilometers from the volcano. Large mudflows, most of which contain hydrothermally altered rock debris, originated at Mount Baker at least eight times during the last 10,000 years. The largest mudflow reached 29 kilometers or more down the valley of the Middle Fork Nooksack River, west of the volcano, about 6,000 years ago. Extensive masses of hydrothermally altered rock that are potentially unstable exist today near the summit of the volcano, especially in the Sherman Crater-Sherman Peak area. Avalanches of this material could be triggered by stream explosions, earthquakes, or eruptions, or may occur because of slow-acting forces or processes that gradually decrease stability. Large avalanches could move downslope at high speed and could grade downvalley into mudflows. Floods caused by rapid melting of snow and ice ...
Date: 1978
Creator: Hyde, Jack H. & Crandell, Dwight Raymond
Partner: UNT Libraries Government Documents Department

Analysis of Fracture in Cores from the Tuff Confining Unit beneath Yucca Flat, Nevada Test Site

Description: The role fractures play in the movement of groundwater through zeolitic tuffs that form the tuff confining unit (TCU) beneath Yucca Flat, Nevada Test Site, is poorly known. This is an important uncertainty, because beneath most of Yucca Flat the TCU lies between the sources of radionuclide contaminants produced by historic underground nuclear testing and the regional carbonate aquifer. To gain a better understanding of the role fractures play in the movement of groundwater and radionuclides through the TCU beneath Yucca Flat, a fracture analysis focusing on hydraulic properties was performed on conventional cores from four vertical exploratory holes in Area 7 of Yucca Flat that fully penetrate the TCU. The results of this study indicate that the TCU is poorly fractured. Fracture density for all fractures is 0.27 fractures per vertical meter of core. For open fractures, or those observed to have some aperture, the density is only 0.06 fractures per vertical meter of core. Open fractures are characterized by apertures ranging from 0.1 to 10 millimeter, and averaging 1.1 millimeter. Aperture typically occurs as small isolated openings along the fracture, accounting for only 10 percent of the fracture volume, the rest being completely healed by secondary minerals. Zeolite is the most common secondary mineral occurring in 48 percent of the fractures observed.
Date: March 1, 2008
Creator: Prothro, Lance
Partner: UNT Libraries Government Documents Department

Deposits of Pre-1980 Pyroclastic Flows and Lahars from Mount St. Helens Volcano, Washington

Description: From introduction: This report describes the character, origin, age, and extent of deposits of pyroclastic flows and lahars that were formed at Mount St. Helens before 1980, and their stratigraphic relations to other rocks and deposits of volcanic and glacial origin.
Date: 1987
Creator: Crandell, Dwight Raymond
Partner: UNT Libraries Government Documents Department

High-pressure mechanical properties of an Area 12, Nevada Test Site tuff

Description: The mechanical properties of tuff from instrument hole UG3, tunnel U12e.06 at the Nevada Test Site have been investigated to 1400 MPa, The shear strength increases from about 5 MHa unconfined to 12 MPa at 300 MPa mean pressure. A brittle-ductile transition was indicated at about 250 MPa. In uniaxial strain, the sample loads to the vicinity of the failure envelope and then is parallel to that envelope up to the highest stresses, 420 MPa. Hydrostatic pressure of 1400 MPa produces about 9% volume compression and 1.3% permanent compaction in this apparently saturated tuff. (auth)
Date: November 19, 1973
Creator: Duba, A.; Abey, A. E. & Heard, H. C.
Partner: UNT Libraries Government Documents Department

Intracrystalline diffusion in clinoptilolite: Implications for radionuclide isolation

Description: Experiments have been performed to measure the rate of exchange diffusion in the zeolite clinoptilolite (CL) for elements important to radionuclide isolation at Yucca Mountain, NV. Clinoptilolite is one of the major sorptive minerals in the tuffs at Yucca Mountain, and occurs both as a major component in zeolitized units (Calico Hills), and in fractures in non-zeolitized tuffs (Topopah Spring). Field evidence and numerical modeling suggests that the movement of fluids through the tuff rocks adjacent to the potential repository may occur via episodic flow through fractures. Under conditions of rapid fracture flow the effective sorptive capacity of fracture-lining clinoptilolite may be controlled by exchange diffusion rather than exchange equilibrium.
Date: November 16, 1995
Creator: Roberts, S.K.; Viani, B.E. & Phinney, D.
Partner: UNT Libraries Government Documents Department

Geochemistry of core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG{number_sign}3, Yucca Mountain, Nevada

Description: The Tiva Canyon Tuff of Miocene age is composed of crystal-poor, high-silica rhyolite overlain by a crystal-rich zone that is gradational in composition from high-silica rhyolite to quartz latite. Each of these zones is divided into subzones that have distinctive physical, mineralogical, and geochemical features.Accurate identification of these subzones and their contacts is essential for detailed mapping and correlation both at the surface and in the subsurface in drill holes and in the exploratory studies facility (ESF). This report presents analyses of potassium (K), calcium (Ca), titanium (Ti), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), barium (Ba), lanthanum (La), and cerium (Ce) in core samples of the Tiva Canyon Tuff from drill hole UE-25 NRG {number_sign}3. The concentrations of most of these elements are remarkably constant throughout the high-silica rhyolite, but at its upper contact with the crystal-rich zone, Ti, Zr, Ba, Ca, Sr, La, Ce, and K begin to increase progressively through the crystal-rich zone. In contrast, Rb and Nb decrease, and Y remains essentially constant. Initial {sup 87}Sr/{sup 86}Sr ratios are relatively uniform in the high-silica rhyolite with a mean value of 0.7117, whereas initial {sup 87}Sr/{sup 86}Sr ratios decrease upward in the quartz latite to values as low as 0.7090.
Date: July 1, 1996
Creator: Peterman, Z.E. & Futa, K.
Partner: UNT Libraries Government Documents Department

Yucca Mountain tuffs

Description: This is a compilation of petrographic slides detailing the microstructure and petrographic character of the tuff deposits associated with the Yucca Mountain radioactive waste repository. It describes crystal structures, clay alterations, and mineral associations. The paper contains a description of the petrographic thin-sections but contains no narrative or conclusions of what the slides suggest with regards to the facility.
Date: August 1, 1996
Partner: UNT Libraries Government Documents Department

Baseline neutron logging measurements in the drift scale test

Description: The Drift Scale Test (DST) is one of the thermal tests being conducted in the Exploratory Studies Facility (ESF). One of the objectives of the DST is to study the coupled thermal-mechanical- hydrological-chemical (TMHC) processes in the ESF at the repository horizon of the potential high-level nuclear waste repository in Yucca Mountain, Nevada. The objectives, the test design, and the test layouts of the DST are included in the test design report by CRWMS M&O Contractor LLNL. The configuration of the DST includes a declining Observation Drift driven mostly east and downward from main tunnel in the ESF, at about 2.827 km from the North portal. The downward slope of the Observation Drift (11.5 to 14.0 percent) ensures a minimum 10 m of middle nonlithophysal Topopah Spring Tuff as the overburden for the DST. The length of the Observation Drift is about 136 m. At the elevation of the DST crown (nominally 10 m below the upper extent of the middle nonlithophysal Topopah Spring Tuff) the Connecting Drift breaks out to the north from the Observation Drift, 136 m from the main tunnel of the ESF. The Connecting Drift extends approximately 40 m to the north from the Observation Drift. A Heater Drift breaks out westward from the Connecting Drift at about 30 m from the Observation Drift. The Heater Drift consists of an 11 m long entry, which includes a plate- loading niche, and a 47 m long heated drift. The nominal diameter of the drifts is 5 m. The detail configuration of the DST, including diagrams showing the drift and borehole layout, is included in the test design report by CRWMS M&O Contractor LLNL. Thermal neutron logging is a method used to determine moisture content in rocks and soils and will be used to monitor moisture content in ...
Date: January 1, 1998
Creator: Lin, W.; Carlson, R. & Neubaurer, D.
Partner: UNT Libraries Government Documents Department

Kinetic measurements on the silicates of the Yucca Mountain potential repository. Final report for October 1994--September 1995

Description: This Final Report includes a summary and discussion of results obtained under this project on the solubilities in subcritical aqueous solutions of Mont St. Hilaire analcime, Wikieup analcime, and Castle Creek Na-clinoptilolite. Also included here are the methods and results of hydrothermal flow-through experiments designed to measure the rates of Na-clinoptilolite dissolution and precipitation at 125{degree}C. In this report, high-temperature solubility measurements made in our lab are integrated and discussed along with the low-temperature measurements made at Yale University. The final report prepared by the group at Yale University (Lasaga et al.) includes a synthesis of dissolution rate measurements made between 25{degree} and 125{degree}C on the Na-clinoptilolite.
Date: August 1, 1995
Creator: Barnes, H.L. & Wilkin, R.T.
Partner: UNT Libraries Government Documents Department