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 23 for “"Southwest Indian Ridge"”.
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Fracture Analysis of the Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge
… formed at the slow-spreading (spreading rate/yr) Southwest Indian Ridge (SWIR)-Atlantis II transform junction. AB is a domal massif composed of lower crustal and upper mantle rocks exhumed along a normal-sense detachment shear zone/fault. OCCs are of high interest since oceanic crust comprises the …
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3D Analysis of Fe-Ti Oxides and How They Affect Crystal-Plastic Deformation in Atlantis Bank, Southwest Indian Ridge
… crystal-plastic deformation in Atlantis Bank, Southwest Indian Ridge by utilizing Micro-CT scanning. This was done through comparing the Micro-CT scans of 15 samples from three different Ocean Drilling Program and International Ocean Discovery Program drill holes using the Nikon NIS Advanced …
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The Impact of Fe-Ti Oxide Concentration on the Structural Ridgity of the Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge
… (OCC) formed at slow-spreading mid-ocean ridges since Fe-Ti oxides are more susceptible to crystal-plastic deformation than silicate minerals. This study investigated the predicted relationship between the presence and concentration of Fe-Ti oxides and the presence and intensity of …
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The influence of ridge geometry at the ultraslow-spreading Southwest Indian Ridge (9º-25ºE) : basalt composition sensitivity to variations in source and process
Between 9º-25º E on the ultraslow-spreading Southwest Indian Ridge lie two sharply contrasting supersegments. One 630 km long supersegment erupts N-MORB that is progressively enriched in incompatible element concentrations from east to west. The second 400 km long supersegment contains three …
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The influence of ridge geometry at the ultraslow-spreading Southwest Indian Ridge (9⁰-25⁰E) : basalt composition sensitivity to variations in source and process
Between 90-25° E on the ultraslow-spreading Southwest Indian Ridge lie two sharply contrasting supersegments. One 630 km long supersegment erupts N-MORB that is progressively enriched in incompatible element concentrations from east to west. The second 400 km long supersegment contains three …
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The evolution of the Indian Ocean triple junction and the finite rotation problem
… Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8°N, 42°W since the Eocene. A detailed survey of the …
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Application of Seasat altimetry to tectonic studies of fracture zones in the Southern oceans
… is investigated along a section of the Southwest Indian Ridge. Geoid anomalies computed from a simple thermal model fairly accurately predict the intermediate-wavelength anomalies across the fracture zones. The shorter wavelength anomalies are consistent with those calculated from …
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Crustal accretion and evolution at slow and ultra-slow spreading mid-ocean ridges
… is to investigate temporal variations in active ridge processes and crustal aging at slow-spreading centers by comparing axial crustal structure with that on conjugate flanks of the slow-spreading Mid-Atlantic Ridge (MAR) (full rate, 20 km/Myr) and the ultra-slow spreading Southwest Indian Ridge …
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Geochemical and rheological constraints on the dynamics of the oceanic upper mantle
… analyses of abyssal peridotites from the Southwest Indian Ridge, I show that the mantle is heterogeneous at a range of length-scales. Abyssal peridotites recovered at ocean ridges are generally interpreted as the depleted residues of melt extraction. I find that melt-rock reaction is a …
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The Effects of Amphibole- and Sulfide-Producing Melts on Crustal Strength in Gabbros of Lower Oceanic Crust in Oceanic Core Complexes, Mid-Atlantic and Southwest Indian Ridges
… complexes in the slow-spreading Mid-Atlantic Ridge (MAR) and the ultraslow spreading Southwest Indian Ridge (SWIR). Dikelets are a texture found in thin section samples from these systems that form as a result of crystal-plastic deformation. Thin section samples from the Atlantis Massif, MARK …
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Geochemical and rheological constraints on the dynamics of the oceanic upper mantle
… analyses of abyssal peridotites from the Southwest Indian Ridge, I show that the mantle is heterogeneous at a range of length-scales. Abyssal peridotites recovered at ocean ridges are generally interpreted as the depleted residues of melt extraction. I find that melt-rock reaction is a …
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Plagioclase preferred orientation in layered mylonites : evaluation of flow laws for the lower crust
… layered gabbro mylonites were collected from the Southwest Indian Ridge (SWIR), ODP Hole 735B. Deformation temperatures are constrained by two-pyroxene thermometry, stress is estimated from grain size, and deformation mechanisms are analyzed by microstructure and the presence or absence of a …
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Interactions between mantle plumes and mid-ocean ridges : constraints from geophysics, geochemistry, and geodynamical modeling
… thesis studies interactions between mid-ocean ridges and mantle plumes using geophysics, geochemistry, and geodynamical modeling. Chapter 1 investigates the effects of the Marion and Bouvet hotspots on the ultra-slow spreading, highly-segmented Southwest Indian Ridge (SWIR). Gravity data …
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Plagioclase preferred orientation in the layered mylonites : evaluation of flow laws for the lower crust
… layered gabbro mylonites were collected from the Southwest Indian Ridge (SWIR), ODP Hole 735B. Deformation temperatures are constrained by two-pyroxene thermometry, stress is estimated from grain size, and deformation mechanisms are analyzed by microstructure and the presence or absence of a …
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The evolution of oceanic gabbros : in-situ and ancient examples
… of shallow melt-rock reaction at mid-ocean ridges. Major-, trace-elements, and isotopes from whole-rocks and minerals from the Lyngen Gabbro, a 480-My old dismembered ophiolite from the Scandinavian Caledonides, indicate that this igneous complex was produced from hydrous supra-subduction …
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Interactions between mantle plumes and mid-ocean ridges : constraints from geophysics, geochemistry, and geodynamical modeling
… thesis studies interactions between mid-ocean ridges and mantle plumes using geophysics, geochemistry, and geodynamical modeling. Chapter 1 investigates the effects of the Marion and Bouvet hotspots on the ultra-slow spreading, highly-segmented Southwest Indian Ridge (SWIR). Gravity data …
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Microseismic observations in the Ceres-Tulbagh aftershock zone, Western Cape, South Africa, and their tectonic implications
… complex from far field stress transfer from the Southwest Indian Ridge. It is proposed, albeit on speculation, that the presence of microseismic activity along the vertically oriented fault zone could be the manifestation of an incipient plate boundary formation.
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Evolution of oceanic gabbros : in-situ and ancient examples
… of shallow melt-rock reaction at mid-ocean ridges. Major-, trace-elements, and isotopes from whole-rocks and minerals from the Lyngen Gabbro, a 480-My old dismembered ophiolite from the Scandinavian Caledonides, indicate that this igneous complex was produced from hydrous supra-subduction …
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Experimental, geochemical and isotopic insights on melting and degassing behavior on Earth
… of arc magmas, and mantle melting at mid-ocean ridges. Through this unlikely “medley” of Earth Science problems, parallels are drawn between experiments investigating melting and degassing at high pressure, geochemical and isotopic fingerprints of the Earth’s oldest rocks, and kinetic processes …
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Trace element geochemistry of oceanic peridotites and silicate melt inclusions : implications for mantle melting and ocean ridge magmagenesis
… genesis and crustal accretion at mid-ocean ridges. It is believed that melts ascend more rapidly than the surrounding mantle, implying a process similar to fractional melting may be occurring, but geochemical evidence for this has been lacking. Furthermore, crustal accretion is thought to be …
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