Global ETD Search
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 40 for “"plate motion"”.
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Oblique Seafloor Spreading, the Malpelo Plate Hypothesis, and Cocos-Nazca-Pacific Plate Motion Circuit
… spreading centers of the Cocos-Nazca plate boundary between 91°W and 94°W (α≈9°), and superfast spreading centers of the East Pacific Rise at the Nazca-Pacific plate boundary between 29°S and 32°S (α≈10°) and perhaps between ≈16°S and ≈22°S (α≈4°). Thus, oblique spreading occurs across …
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Geophysical and petrological constraints on ocean plate dynamics
… thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I …
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Geophysical and petrological constraints on ocean plate dynamics
… thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I …
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Towards a model of the Cenozoic tectonic development of New Zealand
… the New Zealand sector of the Australia-Pacific plate boundary. (2) The tectonic setting during the Paleogene. (3) The nature and location, north of the Alpine Fault proper, of the relative plate motion which is evident as dextral fault displacement on the Alpine Fault. (4) The total amount of …
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Tectonic evolution of Pegasus Basin and the Hikurangi Trench, offshore New Zealand, The
… oblique southwest subduction of the Pacific Plate below the East Coast of the North Island of New Zealand, and the strike-slip faulting that dominates the majority of the South Island of New Zealand. The transition from this strike-slip zone into the actively subducting Hikurangi Trench …
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Transform Faults, Fracture Zones, and the Kinematics of Horizontal Thermal Contraction of Oceanic Lithosphere
Plate rigidity is a key assumption of the plate tectonics theory. The assumption allows us to study plate motion on Earth with great simplicity. However, recent developments in understanding plate cooling have put the assumption of plate rigidity to test. Kumar and Gordon [2009] advance the theory …
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Tip clearance and angle of attack effects upon the unsteady response of a vibrating flat plate in crossflow
… unsteady pressure response of a vibrating flat plate was investigated experimentally. Unsteady pressure measurements were taken for a variety of incidence angles, vibration frequencies and tip clearances over a Mach number range of 0.2 to 0.6. It was found that changes in tip clearance had an …
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Dynamics of the North American Plate: Numerical Development, Mantle Flow Modeling, and Receiver Function Analysis
With only approximately one quarter of plate margins composed of subduction zones, North American plate is an unique continental plate featured with a western active continental margin atop widespread slow seismic velocity anomalies in the asthenosphere, an eastern passive continental margin …
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Characterization of secondary mantle convection from geophysical data and models
… by the shear associated with the lithospheric plate motion, or as helices, formed when sinking cold plumes, falling from the base of the lithosphere are sheared away by the large-scale flow. Our study shows that the secondary convection under the Pacific plate occurs in the form of 3D plumes …
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Mantle flow and lithosphere-asthenosphere coupling beneath the southwestern edge of the North American craton: constraints from shear-wave splitting measurements
… that are mostly parallel to the absolute plate motion direction of North America. Except for a small area in the vicinity of the Llano Uplift in central Texas, no systematic azimuthal variations of the splitting parameters are observed, suggesting that a single layer of anisotropy with …
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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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Tectonic evolution and midplate volcanism in the South Pacific
… with small changes in Pacific-Farallon relative motion. The simple flexural signal of a locked fracture zone may be obscured by tectonic effects, and there is no evidence for the release of shear stress on the fracture zone by vertical slip after leaving the active transform. One such small …
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Discipline-Based Planetary Education Research and Computational Fluid Dynamics Analysis of Mars
… a geophysics study of the possibility of former plate motion (or plate tectonics) on Mars. A 2-D finite element convection model for the mantle of Mars was designed and solved using COMSOL Multiphysics 5.1, to investigate whether or not thermal gradients in a Mars-sized planet could cause …
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LATERALLY HETEROGENEOUS SEISMIC ANISOTROPY INVESTIGATED BY SHEAR WAVE SPLITTING ANALYSES
… by a simple geodynamic model invoking absolute plate motion related to simple shear in the lithosphere-asthenosphere transitional layer and mantle flow deflected by the thick lithospheric root of the basin in the upper asthenosphere. In the vicinity of the 2019 Ridgecrest M7.1 earthquake …
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Elastic and viscous anisotropy in Earth's mantle : observations and implications
… a model of shear in the upper mantle due to plate motion, a model of buoyancy-driven instabilities, and a model of flow in the mantle wedge of subduction zones. My models revealed that anisotropic viscosity leads to substantial changes in all the flows I examined. In the upper mantle beneath …
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Analysis of Model-driven vs. Data-driven Approaches to Engaging Student Learning in Introductory Geoscience Laboratories
… physical geology lab modules for calculating plate motion. One engages students with a model-driven approach using contrived data. Students are taught a descriptive model and work with a set of contrived data that supports the model. The other lab exercise uses a data-driven approach with real …
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Late Cretaceous-Cenozoic Accretionary History of Volcanic Arcs and the Bering Oceanic Plateau in the Northwestern in Alaska and Northeastern Russia Constrained by Integration of Geologic, Geophysical, and Radiometric Data
The political division of the northern Pacific plate margin between northeastern Asia in Russia, the Bering Sea, and Alaska and the Aleutian Islands in the USA has slowed the tectonic understanding of this vast, 9,100,000 km2 region. In this study I have compiled geologic, gravity, magnetic, …
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Kinematically consistent, elastic block model for the eastern Mediterranean constrained by GPS measurements
… blocks are considered, including the major plates, based largely on previous geodetic, seismic, and geologic studies: Eurasia (EU), Nubia (NU), Arabia (AR), Anatolia (AN), Caucasus (CA), South Aegea (AE), Central Greece (GR), North Aegea (NE), Southeast Aegea (SE), Macedonia (MA), and Adria …
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Space-Time Analysis of Magmatism: Evidence for a Early Cryogenian Plume Track in Eastern Laurentia
… 735 to 705 Ma observed in the north, and yield a plate motion rate of ~2 cm/year.
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