Global ETD Search
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Showing 1 to 15 of 15 for “"Melt Transport"”.
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Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle
… questions regarding the mechanisms of melt transport and its effects on the shallow mantle. Chapter 1 details the current understanding of melt migration from observations at mid-ocean ridges and ophiolites. Chapter 2 uses the size distribution and abundance of dunites measured in the …
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Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle
… questions regarding the mechanisms of melt transport and its effects on the shallow mantle. Chapter 1 details the current understanding of melt migration from observations at mid-ocean ridges and ophiolites. Chapter 2 uses the size distribution and abundance of dunites measured in the …
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Geochemical properties of the Beni Bousera (N. Morocco) peridotites : a field and laboratory approach to understanding melt infiltration and extraction in an orogenic peridotite massif
… and trace element patterns suggest partial melting of the peridotite played a significant role in the evolution of the massif, as has been previously suggested for other orogenic peridotites. Heterogeneous zones - regions throughout the massif with diverse groups of peridotites and …
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Seismic constraints on the processes and consequences of secondary igneous evolution of Pacific oceanic lithosphere
… operation of both focused and diffuse modes of melt transport through the lithosphere. Analysis of seismic observations from Guaymas Basin, in the Gulf of California, endeavor to advance our understanding of sill-driven alteration of sediments, an important consequence of secondary magmatism. We …
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Seismic constraints on the processes and consequences of secondary igneous evolution of Pacific oceanic lithosphere
… operation of both focused and diffuse modes of melt transport through the lithosphere. Analysis of seismic observations from Guaymas Basin, in the Gulf of California, endeavor to advance our understanding of sill-driven alteration of sediments, an important consequence of secondary magmatism. We …
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Spatial-Statistical Properties of Geochemical Variability as Constraints on Magma Transport and Evolution Processes at Ocean Ridges
… petrogenetic and scientific: crystallization, melt transport, and sampling. In Chapter 2, I use spatial patterns of mid-ocean ridge basalt (MORB) glass variability to test competing hypotheses about crystallization in the thermal boundary layer beneath ocean ridges. I develop the hypothesis …
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Basalt petrogenesis beneath slow- and ultraslow-spreading Arctic mid-ocean ridges
To explore the ability of melting mafic lithologies to produce alkaline ocean-island basalts (OIB), an experimental study was carried out measuring clinopyroxene (Cpx)melt and garnet (Gt)-melt partition coefficients during silica-poor garnet pyroxenite melting for a suite of trace elements, …
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Basalt petrogenesis beneath slow- and ultraslow-spreading Arctic mid-ocean ridges
To explore the ability of melting mafic lithologies to produce alkaline ocean-island basalts (OIB), an experimental study was carried out measuring clinopyroxene (Cpx)- melt and garnet (Gt)-melt partition coefficients during silica-poor garnet pyroxenite melting for a suite of trace elements, …
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Effects of Glaciation on Volcanism in Iceland
… rates in the mantle, causing enhanced mantle melting rates. However, existing theoretical work cannot account for large variations of Rare Earth Element (REE) concentrations in the Icelandic lavas. Lavas erupted during the last deglaciation are depleted in REEs by up to 70\%; whereas, existing …
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Kinetics of chemical exchange during melting of planetary interiors
… the kinetics of chemical exchange during partial melting within the mantles of the terrestrial planets. Chapter 1 presents experiments on the diffusion rates of La, Ce, Nd, Dy and Yb in diopside at pressures of 0 to 2.5 GPa and temperatures of 1050 to 1450 'C. The results demonstrate a large …
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QUANTIFICATION OF MELT DISTRIBUTION, MELT CONNECTIVITY, AND ANISOTROPIC PERMEABILITY OF DEFORMED PARTIALLY MOLTEN ROCKS USING X-RAY MICROTOMOGRAPHY
… and ocean water are all influenced by how the melt is distributed in partially molten rocks, and how easily it can flow through the partially molten mantle beneath these ridges. In particular, it is often assumed that most of the melt ascends through isolated channels that direct it towards the …
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Carbon systematics of the Icelandic crust and mantle
… to the low solubility of carbon within silicate melt, these undegassed basalt suites are rare. The majority of basalts have lost their mantle carbon information en route to eruption through the crust. Various crustal processes act to modify the geochemistry of melts before eruption, therefore it …
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Timescales of magma residence and transport underneath Iceland
… the timescales of pre-eruptive residence and transport: the Skuggafjöll eruption, Bárðarbunga volcanic system; the Borgahraun eruption, Theistareykir volcanic system; and the Laki eruption, Grímsvötn volcanic sytem. These findings are then synthesised within an Icelandic and global framework. …
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Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics
… from the plumes. The dynamics of mantle flow and melting at ridge-centered plumes are investigated in Chapters 3 using three-dimensional, variable-viscosity, numerical models. Three buoyancy sources are examined: temperature, melt depletion, and melt retention. The width W to which a plume spreads …