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Showing 1 to 20 of 76 for “"tuff"”.
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Microbial transport in volcanic tuff Rainier Mesa, Nevada test site
… the mobilization of microorganisms in volcanic tuff and impose conditions that are different from those in the rock matrix away from water flow paths. To address the potential for bacterial transport with water in deep fractured tuffs, flow water and six rock samples were taken progressively …
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Correlation and Paleoenvironments above West T9.3 Tuff, Pisco Formation, Peru
… this study, we correlated, mapped, and dated a tuff couplet and associated beds over 25 km2. We measured eight sections that include the tuffs and conducted detailed facies analysis. Sections were broken down into eight facies including: hummocky cross-stratified diatomaceous siltstone, muddy …
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Geochemical and sedimentological investigations of Youngest Toba Tuff ashfall deposits
… The products of this eruption, the Youngest Toba Tuff (YTT), have been implicated in global and regional climate deterioration with widespread ecological effects. In this thesis I study the YTT co-ignimbrite ashfall, in particular the mechanisms of transport, sedimentation and preservation of ash …
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Mechanical and cathodic protection aspects of multi-barrier tuff repository canister designs
The main objective of this work is to design a Multi-Barrier container for storing spent fuel. Design analysis included dimensioning the canister and the concrete pedestal utilizing available materials data, stress calculations and corrosion data. The various corrosion modes were identified, and a …
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Pore-water extraction from unsaturated tuff by compression methods, Nevada Test Site
Includes bibliographical references.
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Long-term desorption behavior of uranium and neptunium in heterogeneous volcanic tuff materials
… using four well-characterized volcanic tuff cores collected from southeast of Yucca Mountain, Nevada. The objectives of the experiments were to 1. Demonstrate a methodology aimed at characterizing <italic>distributions<italic> of sorption parameters (attributes of multiple sorption …
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Thermal Modeling of Cooling Time of Submarine Dacite Lapilli Tuff: Brothers Volcano, Kermadec Arc
<p>Little is known about submarine volcanoes' eruptive histories and styles, even though they are essential to developing island arc systems and represent the second largest volcanic systems on Earth. Scientific drilling allows for the opportunity to study these systems. This study focused on two …
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Equilibrium studies of ion sorption on zeolitized tuff from Rainier Mesa, Nye County, Nevada
… ions on zeolitized tuff from Rainier Mesa, Nevada, and on clinoptilolite from Jordan Valley, Oregon. The fractional uptake of the ions on the zeolitized tuff was investigated so that sorption isotherms and partitioning coefficients describing the affinity of the ions …
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Parametric studies of the criticality of radioactive spent fuel canisters in a tuff repository
… was completely flooded, however, the effect of tuff saturation was minimal. Also, different materials and canister thickness changed k{dollar}\sb{\rm eff}{dollar} between 6.44% and 8.75%. The term k{dollar}\sb{\rm eff}{dollar} expresses the ability of nuclear fuel to sustain a chain reaction. …
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Modeling the rates of lead and strontium uptake by zeolitized tuff from Rainier Mesa, Nevada Test Site, Nevada
… (Pb) and Strontium (Sr) uptake by zeolitized tuff from Rainier Mesa, NTS, was studied as a function of pH, ionic strength, and metal concentration; To test the hypothesis that sorption of Pb occurs through surface precipitation and Sr sorbs through diffusion, the data were modeled by a first …
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Geologic Mapping along the Benton Spring Fault, Nevada: Dextrally-offset Tuff-filled Paleovalleys in the Central Walker Lane
<p>Documenting the spatiotemporal evolution of fault systems along the western margin of North America is a prerequisite for characterizing the forces which drive faulting across the U.S. Cordillera. Within the Cordillera, the Walker Lane, characterized by active intracontinental faults, straddles …
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Paragenesis of Lacustrine Microbialites in the Upper Wilkins Peak Member, Green River Formation, Wyoming
… analyzed that are associated with the “layered tuff”. Samples were collected from correlated sections along a NW to SE, 24 km line of section from lake margin towards lake center. XRD, SEM/EDS, and petrographic analysis show differences in diagenesis above and below the layered tuff.</p> …
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Investigation of Natural Zeolitic Tuffs on their Ability for Sewage Cleaning Purposes
… material used was brownish and reddish zeolitic tuffs. Both materials were found to be very different from each other in their chemical and mineralogical compositions. The untreated sample of reddish zeolitic tuff showed a very high capacity for ammonium adsorption (46g/kg) from an ammonium …
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Comparison of Breien and Canonball Volcanic Tuffs in Southern North Dakota
<p>Volcanic tuffs of Cretaceous age are found sandwiched in many outcrops in southwestern North Dakota. The lateral extent of many of these tuffs has been mapped, but distinguishing discrete tuffs is a work in progress. This report looks at two tuffs found along the Cannonball River south of …
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Characterization of pozzolanic cement for radioactive waste disposal
… by mixing lime or portland cement with volcanic tuff, a natural pozzolanic material extracted from Yucca Mountain, Nevada; Portland-pozzolan and lime-pozzolan mixtures were created, analyzed and tested for compressive strength. In addition, the pH of several mixtures was monitored and the values …
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Post-Closure Silica Transport in the Proposed High Level Radioactive Waste Repository at Yucca Mountain, Nevada
… of Las Vegas, consists of horizontally bedded tuff deposits. Although the region is very arid, enough water exists in the tuffs to create a vapor dominated geothermal system as the pore water evaporates, circulates and recondenses. This study examines how silica leaching might occur as a result …
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Tephrostratigraphy, petrography, geochemistry, age and fossil record of the Ganigobis Shale Member and associated glaciomarine deposits of the Dwyka Group, Late Carboniferous, southern Africa
… as well as extrabasinally derived ashfall tuff beds characterise the more than 40 m thick mudstones and provide the basis for an integrated high-resolution biostratigraphic and tephrostratigraphic framework. The Ganigobis Shale Member contains remains of paleoniscoid fishes, bivalves, …
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The Provenance of Eocene Tuff Beds in the Fossil Butte Member of the Green River Formation of Wyoming: Relation to the Absaroka and Challis Volcanic Fields
… Formation at Fossil Basin, preserve ash fall tuffs deposited in ancient Fossil Lake. 40Ar/39Ar dating of sanidine yielded eruptive ages of 51.29 ± 1.29 Ma and 52.20 ± 3.08 Ma for two of the tuff beds within Fossil Basin. Immobile element and mineral compositions of Fossil Basin tuffs indicate …
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Volcanic and sedimentary processes in phreatomagmatic volcanoes
… interaction. Phreatic maars and phreatomagmatic tuff-rings are underlain by pipe-like diatremes but these structures are poorly developed or absent in surtseyan tuff-rings. Comparisons of phreatomagmatic volcanoes with their eroded diatreme equivalents, which contain subsided …
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High-Resolution Correlation of a Time-Bounded Unit of the Pisco Formation, Peru
… by two time markers, an 40Ar/39Ar-dated white tuff at the base and an 40Ar/39Ar-dated tuff couplet at the top. This interval was chosen because of the continuity and excellent exposure of the tuff beds at six distinct locations in a linear transect 30 km long. Correlation of units was achieved …
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