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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 216 for “"volcanism"”.
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Subglacial rhyolite volcanism at Torfajökull, Iceland
Subglacial rhyolite eruptions at Torfajökull, Iceland have produced a variety of volcanic edifices during the last glacial period (115-11 ka). These range from small-volume (<0.1 km<sup>3</sup>) volcanoes, such as Bláhnúkur and Dalakvíslfell, to larger volume (~1 km<sup>3</sup>) flat-topped tuyas …
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Understanding Non-Plume Related Intraplate Volcanism
Intraplate volcanism is a worldwide phenomenon producing volcanoes away from active plate boundaries, a process that cannot yet be sufficiently explained by plate tectonic processes, and thus is still a missing piece in the understanding of the dynamics and evolution of our planet. Models for the …
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Effects of Glaciation on Volcanism in Iceland
… that take account of the diachronous response of volcanism to deglaciation. Numerical models of mantle flow and mantle melting response to the glaciation and deglaciation are developed. A time-lag sampler is incorporated to represent the time lag between the melt production at depths and the …
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Tectonic evolution and midplate volcanism in the South Pacific
… Cook-Austral Island chain, multiple episodes of volcanism have left a diverse population of seamounts. Volume estimates from geophysical data and modeling show that one-half to two-thirds of the volcanic material is over thirty million years old, while the remainder is less than five million …
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Explosive Volcanism in the Kenyan Rift: A Tephrostratigraphic Perspective
… to establish more comprehensive records of volcanism. In this study, two ~Holocene sediment core sequences, Lake Chala (Tanzania) and Lake Naivasha (Kenya), are investigated for the presence of cryptotephra deposits to provide better constraints on eruption histories. The complete Holocene …
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Tectonic evolution and midplate volcanism in the South Pacific
Thesis (Ph.D.)--Joint Program in Oceanography, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, 1999.
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Petrological and rheological controls on volcanism to terrestrial planets
Through experimental petrology and geodynamic modeling, processes of melting under thick lithospheres on the Earth and the moon are investigated. Phase equilibrium experiments were carried out on Apollo 14B and 15C picritic glasses (Chapters 5 and 6) and on a Sierran high-potassium lava (Chapter …
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Deciphering the Tectonics of the Caucasus from Post-Collisional Volcanism
… mantle derived post-collisional magmatism. Volcanism began 5-15 Ma after the initial collision occurred, and after the crust had already thickened to 45-60 km. This thesis presents bulk rock and mineral element and isotope geochemistry to assess the role of asthenosphere, lithosphere and …
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Evidence From High Ni Olivine For Diverse Primitive Magmas In Cascade Volcanism
… appears to challenge the widely held idea that volcanism there is derived primarily from basaltic parental melts that are unusually hot and dry compared to those in other arc systems.</p>
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Visualizing and Understanding Tectonism and Volcanism on Earth and Other Terrestrial Bodies
<p>This dissertation presents new methods of visualizing, teaching, assessing, modeling, and understanding tectonics on Earth and other celestial bodies. Tectonics is the study of planetary lithospheres and includes impact, plate, plume, cryo- and gravitational mechanisms. This dissertation is …
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A Geophysical Survey Of Active Volcanism In The Central And Southern Andes
… plate results in great earthquakes and active volcanism along the Andean margin. The Central Volcanic Zone (CVZ) between 15°S and 28°S and the Southern Volcanic Zone (SVZ) between 33°S and 46°S are separated by a zone of flat slab subduction and differ significantly in the manifestation of …
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Miocene extension and volcanism in the Caliente caldera complex, Lincoln County, Nevada
Includes bibliographical references.
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Mafic volcanism in the Colorado Plateau/Basin-and-Range Transition Zone, Hurricane, Utah
The Hurricane volcanic field (HVF) is a small-volume (0.48 km{dollar}\sp3{dollar}) mafic volcanic field in the Colorado Plateau/Basin & Range Transition Zone located in the eastern part of the St. George basin in southwestern Utah. Strombolian-Hawaiian style eruptions produced thin (10 m) a'a lava …
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Unravelling the Dynamical Mechanisms Underpinning Intra-Plate Volcanism Within and Around Earth's Continents
… mechanisms at the root of Earth's intra-plate volcanism from a computational fluid dynamics perspective. It analyses different convective processes that enable and sustain decompression melting in the uppermost asthenosphere and, subsequently, proposes novel pathways to understanding the …
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Unravelling the Dynamical Mechanisms Underpinning Intra-Plate Volcanism Within and Around Earth's Continents
… mechanisms at the root of Earth's intra-plate volcanism from a computational fluid dynamics perspective. It analyses different convective processes that enable and sustain decompression melting in the uppermost asthenosphere and, subsequently, proposes novel pathways to understanding the …
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Mesozoic alkaline volcanism and mantle evolution of the southwestern São Francisco craton, Brazil
… that these rocks may be coeval to the felsic volcanism of the Araxa Group which was recently dated at 794 Ma by zircon work (Pimentel et al., 1991). Funher to the west still, combined samples from the Nique!andia mafic-ultramafic igneous complex and associated granitic basement rocks yield a …
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Martian meteorites as windows into planetary volcanism: insights from olivine-phyric shergottite meteorites
… This allows for the development of models of volcanism using suites of meteorites, rather than relying solely on single meteorites. One group of shergottite meteorites, comprising approximately 20 samples with crystallisation ages from 2.4 to 0.35 Ga, share similar geochemical characteristics …
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Tectonics and volcanism on Venus : constraints from topographic relief, impact cratering, and degassing
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1995.
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Neotectonic evolution of Grand Canyon : interaction between volcanism, river incision, epeirogenic uplift, and faulting
<p>This thesis focuses on the effects of volcanism, river incision, epeirogenic uplift, and faulting on the landscape evolution of the Grand Canyon region. In the first chapter the migration of increasingly asthenospheric basaltic volcanism is used to constrain lithospheric modification of the …
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