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 89 for “"Mid-Ocean Ridge"”.
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Mantle Heterogeneity Through Mid-Ocean Ridge Basalts
… Earth's upper mantle is often examined through mid-ocean ridge basalts (MORB), which contest the prevalent assumption of a well-mixed convecting mantle. This dissertation delves into studying mantle heterogeneity from a local to regional scale. Initially, petrological models were utilized to …
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Fluid Flow Processes at Mid-Ocean Ridge Hydrothermal Systems
… structure and temporal variability of mid-ocean ridge hydrothermal systems are examined from a largely theoretical standpoint. The nature of tidal signals is considered in detail and there is a discussion of the mechanisms by which the tidal modulations observed at seafloor hydrothermal …
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Rayleigh waves from mid-ocean ridge earthquakes : source and path effects
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth and Planetary Science, 1972
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Experimental constraints on the generation and evolution of mid-ocean ridge basalts
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991.
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The geochemistry of boron and lithium in mid -ocean ridge hydrothermal vent fluids
… processes occurring below the seafloor along the mid-ocean ridge axis. Boron and lithium in hydrothermal vent fluids were studied because previous results indicated that these elements might be useful tracers of water-rock processes. The B concentration and the Li isotopic signature of …
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Focal depths and mechanisms of mid-ocean ridge earthquakes from body waveform inversion
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1986.
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Examining the effects of mid ocean ridge topography on 3D marine magnetometric resistivity model responses
… order to analyze and invert MMR data taken near Mid Ocean Ridges, it is important to understand the effects of ridge topography on MMR models. To analyze these effects a 3D MMR forward modeling program MMR3D_fwd is used to model Mid Ocean Ridges with varying slopes, resistivities, and …
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Examining the effects of mid ocean ridge topography on 3D marine magnetometric resistivity model responses
… order to analyze and invert MMR data taken near Mid Ocean Ridges, it is important to understand the effects of ridge topography on MMR models. To analyze these effects a 3D MMR forward modeling program MMR3Df̲wd is used to model Mid Ocean Ridges with varying slopes, resistivities, and …
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Oceanic lithosphere magnetization : marine magnetic investigations of crustal accretion and tectonic processes in mid-ocean ridge environments
… in two marine environments; along the ridge axis of the fast spreading East Pacific Rise (EPR) (9º 25’-9º 55’N) and at Kane Megamullion (KMM) (23º 40’N), near the intersection of the slow-spreading Mid Atlantic Ridge with Kane Transform Fault. Marine magnetic anomalies and magnetic …
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The geochemistry of selected mid-ocean ridge basalts from the Southern mid-Atlantic ridge (40°- 55°S)
… recovered from this section of the southern Mid-Atlantic Ridge (SMAR), and significantly expanded the global suite of samples from slow-spreading ridges.
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Oceanic lithosphere magnetization : marine magnetic investigations of crustal accretion and tectonic processes in mid-ocean ridge environments
… in two marine environments; along the ridge axis of the fast spreading East Pacific Rise (EPR) (90 25'-90 55'N) and at Kane Megamullion (KMM) (230 40'N), near the intersection of the slow-spreading Mid Atlantic Ridge with Kane Transform Fault. Marine magnetic anomalies and magnetic …
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Geochemistry of deep-sea hydrothermal vent fluids from the Mid-Cayman Rise, Caribbean Sea
… two vent fields at the ultraslow spreading Mid-Cayman Rise, Earth’s deepest mid-ocean ridge. In Chapter 2, abiotic organic synthesis is shown to occur via two distinct mechanisms in the serpentinizing Von Damm system. Chapters 3 and 4 present in-depth studies of the chemical and isotopic …
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Hydrothermal alteration of the ocean crust: insights from Macquarie Island and drilled in situ ocean crust
… process in the formation and aging of the ocean crust, influencing its structure, physical and chemical properties, and the composition of the oceans and the mantle. The impact of hydrothermal circulation on mid-ocean ridge processes depends on the composition and volume of circulating …
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Paleocene Turbidite Deposition in the Central American Seaway (NW Costa Rica): Geochemical Analysis and Provenance of Detrital Spinel and Clinopyroxene
The Central American Land Bridge is the crucial connection between North and South America, and the Miocene closure of the Panama seaway led to a change in global oceanic circulation patterns. Modern Costa Rica is part of the island arc that formed over the western Caribbean subduction zone, and …
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Geophysical and geochemical constraints on submarine volcanic processes
Submarine volcanic systems form new oceanic crust, host unique chemosynthetic ecosystems, concentrate rare metals, and provide a conduit for chemical transfer from the Earth's interior to hydrosphere. Although our understanding of submarine volcanoes has been historically limited due to their …
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Geophysical and geochemical constraints on submarine volcanic processes
Submarine volcanic systems form new oceanic crust, host unique chemosynthetic ecosystems, concentrate rare metals, and provide a conduit for chemical transfer from the Earth's interior to hydrosphere. Although our understanding of submarine volcanoes has been historically limited due to their …
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Homogeneous equilibria in hydrothermal fluids at near critical conditions.
… from these fluids. Activity ratios computed for mid-ocean ridge hydrothermal vent fluids and alkali chloride solutions are not sensitive to the initial pH, and can provide quantitative information regarding subsurface fluid-mineral equilibria. Analysis of mid-ocean ridge fluids in the …
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Geochemistry of deep-sea hydrothermal vent fluids from the Mid-Cayman Rise, Caribbean Sea
… vent fields at the ultra slow spreading Mid-Cayman Rise, Earth's deepest mid-ocean ridge. A wide variety of possible temperatures and substrates for fluid/rock reaction exist at ultraslow spreading ridges. The flux of chemicals delivered to the ocean by circulating vent fluids exerts a …
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Trace element geochemistry of oceanic peridotites and silicate melt inclusions : implications for mantle melting and ocean ridge magmagenesis
… to basalt 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 …
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Slip on ridge transform faults : insights from earthquakes and laboratory experiments
The relatively simple tectonic environment of mid-ocean ridge transform fault (RTF) seismicity provides a unique opportunity for investigation of earthquake and faulting processes. We develop a scaling model that is complete in that all the seismic parameters are related to the RTF tectonic …
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