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Showing 1 to 19 of 19 for “"ignimbrite"”.
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3D and 4D Modeling of Ignimbrite Eruptions
… magma chamber and other possible sites for ignimbrite eruption has been accelerated by the development of the areas surrounding the volcanoes. Early detection of eruptions is the most important aspect when trying to reduce casualties from an eruption. The magma chamber at Yellowstone has …
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Relationships between the geomechanics and petrography of ignimbrite
Fundamental petrographic controls on ignimbrite strength are examined, and those aspects of the texture and fabric of the rocks which are primarily responsible for the strength of ignimbrite identified. The range of strength exhibited by ignimbrite is quantified, and the value of common, …
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The initiation and evolution of ignimbrite faults, Gran Canaria, Spain
… of meters within moderately and densely welded ignimbrite units on the caldera island of Gran Canaria, Spain. Through the investigation of fault populations within different ignimbrite units I have examined how the fault architecture changes with accumulated displacement, identified the factors …
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An investigation of two periglacial landforms on ignimbrite blockslopes in Kluane National Park and Reserve, Yukon Territory
… the treeline, mantling a blocky open matrix of ignimbrite cobble-to-boulder material. BSTs differ from expected solifluction characteristics by showing apparent periodicity, large sample sizes, oblique orientations relative to their slope, and material too coarse to support the formation of ice …
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Understanding the evolution of compositional zoning in San Juan Volcanic Field ignimbrites using iron isotope ratios
… remnant of a large Tertiary aged calc-alkaline ignimbrite flare up. Previous work has led to detailed characterization of the volcanic stratigraphy and temporal evolution of many large calderas. Ignimbrites include both compositionally zoned rhyolitic to dacitic eruptions as well as monotonous …
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Near-vent processes of the 273 ka Poris eruption (Tenerife)
… between proximal and counterpart distal ignimbrites. Consequently, understanding of the full course of these eruptions and how to analyse their deposits for purposes of hazard assessment has been limited. This study aims to address the limitations by using a lithofacies architecture …
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Geochemical and sedimentological investigations of Youngest Toba Tuff ashfall deposits
… effects. In this thesis I study the YTT co-ignimbrite ashfall, in particular the mechanisms of transport, sedimentation and preservation of ash deposits. I use distal marine and terrestrial ash sediments: a) to estimate the volume of YTT ash fallout; b) to quantify variability in the …
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Resolving abrupt palaeoenvironmental changes in a lake sediment sequence from Ioannina, northwest Greece
… Two visible tephra layers, the Campanian Ignimbrite (CI/Y-5; ca. 39.8 ka BP) and Pantelleria Green Tuff (PGT/Y-6; ca. 45.7 ka BP) are identified, as well as the Holocene Vallone del Gabellotto cryptotephra marker (E-1; ca. 8.3 ka BP). Evidence for repeated remobilisation and redeposition …
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Ignimbrítið í Hólafjalli og tengdar myndanir - Rakning myndunarsögu gjóskubergs í Fannardal í Norðfirði
… gjóskubergsmyndanir sem líktust ignimbríti (e. ignimbrite). Hlíðar Hólafjalls í Fannardal geyma slíkar gjóskubergsmyndanir grænleitar að lit og þær eru viðfangsefni þessarar rannsóknar. Markmið rannsóknarinnar er helst að rekja myndunarsögu berglaganna. Myndununum var skipt upp í þrjú snið: lag …
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A Geophysical Survey Of Active Volcanism In The Central And Southern Andes
… body on Earth and erupted at least 10,000 km3 of ignimbrite in the Late Miocene (10-1 Ma). In this dissertation, I use InSAR (interferometric synthetic aperture radar), thermal remote sensing, and seismology to investigate active volcanism in the Central and Southern Andes. InSAR and thermal …
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The Volcanic Evolution of Syrtis Major Planum, Mars
… products of this magma reservoir include an ignimbrite, now exposed in Nili Patera. The second phase of magmatism (~2.7 Ga – ~2.2 Ga) consisted of temporally sporadic volcanism, spatially concentrated in the central caldera complex, and includes two examples of high-silica lava units. These …
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Characterizing the deformation history of the southern Mina Deflection: field and structural studies in the Huntoon Mountains, California-Nevada
… plagioclase, Nagorsen-Rinke et al., 2013) latite ignimbrite. These units are overlain in buttress and angular unconformity by basalt lavas and mafic volcanic centers that range in age from 4.08 ± 0.10 (<sup>40</sup>Ar/<sup>39</sup>Ar groundmass plagioclase, Tincher and Stockli, 2009) to 2.996 ± …
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A GIS-Based Volcanic Hazard and Risk Assessment of Eruptions Sourced within Valles Caldera, New Mexico
… distribution and runout of the Battleship Rock Ignimbrite. Once calibrated, hazards are simulated at two other vent locations determined from probability distributions of structural features, in order to generate the final hazard maps.<p>In assessing communities’ hazard preparedness, social …
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Extractable organics and colour in a bleached kraft mill effluent land application system and recipient ground waters
… movement through fractured zones in four major ignimbrite aquifers. Wells were placed at depths between 9 and 110 m, and at distances from immediately adjacent to 2.7 km from the seepage area to sample ground water from these zones. Contamination was found largely within the highly fractured, …
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Engineering geological characterization of volcanic rocks of ethiopian and sardinian highlands to be used as construction materials
… of aphyric basalt, phyric basalt, trachybasalt, ignimbrite/rhyolite, tuff and minor trachyte. Thorough literature review has been conducted on volcanic rocks as construction materials and from the compiled information a laboratory testing program was envisaged and conducted on the samples …
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Use of local available material for inverted pavement technique
… basalt, quartzite, trachite, dolomite and ignimbrite. All these are materials with good features such as mechanical endurance and durability. An in-depth bibliographic research was done about the 'Inverted Pavement’ technique for understanding the behavior of this type of paving during the …
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Understanding topographic evolution of continents with landscape evolution simulations: the case of North America
… intensities. This time is coeval with the ignimbrite flare-up in the western U.S. and the drainage reversal within the Colorado Plateau. I conclude that this mid-Cenozoic regional uplift is due to increased lithospheric buoyancy and dynamic uplift, both of which are associated with the …
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Buffalo Canyon: An Oligocene Greisen-Like Intrusion-Related Gold Deposit in the Union Mining District, Nye County, Nevada
… volcanism during slab rollback that led to the ignimbrite flare-up in the central Nevada. Though most RIRG systems in Nevada could indeed be Mesozoic, the research on Buffalo Canyon opens the possibility that similar deposits may also be related to much younger intrusions that may be largely …
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PETROLOGIC AND GEOCHEMICAL ANALYSIS OF INTERMEDIATE TO MAFIC MAGNETITE-BEARING VOLCANIC FLOWS AND ASSOCIATED DIKES IN THE KNIGHT RANGE, GRANT COUNTY, NEW MEXICO
<p>The Knight Range of southwestern Grant County, New Mexico, is made up of a northeast-dipping package of Cretaceous-Tertiary volcanic, volcaniclastic, and sedimentary units. It is located in the Burro Uplift, south of the Tyrone mining district, at the intersection of the Mogollon-Datil volcanic …