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 485 for “"magma"”.
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Titanite zoning and magma mixing
… Caledonian age pluton that displays evidence of magma-mixing processes at depth and also contains notable amounts of titanite. Samples of different host granite and diorite enclave lithologies and relationships were documented and collected in order to asses the ability of titanite to retain …
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The influence of magma supply and eruptive processes on axial morphology, crustal construction and magma chambers
… the Earth is created at mid-ocean ridges where magmas rise from the mantle and cool to form the oceanic crust. The objective of this Thesis is to examine the influence of magma supply and eruptive processes on axial morphology, crustal construction, and the properties of crustal magma chambers …
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The influence of magma supply and eruptive processes on axial morphology, crustal construction and magma chambers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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Magma genesis beneath active continental rifts
… easily-fusible mantle components in driving magma genesis in the absence of significant thermal anomalies. These heterogeneous mantle domains may be linked to the complex tectonic histories of continents, which often involve multiple stages of accretion and associated recycling of materials …
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Quantifying magma recharge at Parinacota volcano, northern Chile (52 ka - recent): Insight from the Magma Chamber Simulator
The Magma Chamber Simulator (MCS; Bohrson et al., 2014) was used to produce new thermodynamic models that constrain and quantify recharge and fractional crystallization (RFC) processes for the Old Cone (OC; 52-20 ka; 56-66 wt.% SiO<sub>2</sub>) and Healing Flows (HF; >8 ka-recent; 58-64 wt.% …
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Magma mingling : Die hydrodynamische Genese magmatischer Dispersionen
… Silikatschmelzen treten im gesamten Spektrum magmatischer Aktivität auf. Dabei kann es sowohl zu Magma mingling-, als auch zu Magma mixing-Prozessen kommen. Magmatische Enklaven und Dispersionen sind dabei Zeugen der ehemaligen Interaktion und Vermischung der beteiligten Schmelzen. Diese …
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Timescales of magma residence and transport underneath Iceland
… Borgarhraun eruption was fed by mixed primary magmas that ponded near the Moho (approximately 24 km depth). Diffusion chronometry conducted on olivine macrocrysts show that crystal entrainment into the carrier-liquid took place approximately 13 days before eruption with some crystals having …
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Magma genesis in the northern Lau Basin, S.W. Pacific
… the inner wall of the northern Tonga trench. The magma genesis of these lava suites is related to the structural and geochemical controls imposed during the tectonic evolution of the region. The geochemical controls result from processes related to the mantle dynamics in the northern Lau Basin, …
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Origin of net-veined and mixed-magma ring intrusions
Net-veined and mixed-magma ring intrusions are a characteristic simultaneous emplacement of mafic, intermediate and silicic magmas. Net-veined ring-intrusions consist of areas of granophyric net-veined mafic to intermediate rock which elsewhere forms rounded to elongate pillows in a silicic host …
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Crystal mobilisation in convecting magma chambers: an analogue experimental approach
… igneous intrusions from originally liquid magma chambers display a large number of different sedimentary features. These features include the gravitational collapse of sidewalls producing slumps and the layering produced by gravitational settling of crystals. In the chamber fluid-dynamic …
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Mantle upwelling, melt generation, and magma transport beneath mid-ocean ridges
… the melt appears to accumulate in small crustal magma chambers, before erupting in small batches to form numerous overlapping hummocky lava flows and small volcanoes. This suggests that crustal accretion, particularly at slow-spreading centers, may be a highly discontinuous process. …
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Mantle-Melting at High Pressure: Experimental Constraints on Magma Ocean Differentiation
… are relevant to the crystallisation of a deep magma ocean, that likely existed during Earth’s accretion. The melting relations of potential magma ocean compositions, such as peridotitic and chondritic bulk compositions, were investigated using multianvil apparatus at pressures of 25-26 GPa and …
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Magma emplacement and deformation in rhyolitic dykes : insight into magmatic outgassing
… distribution of intruded particles and degree of magmatic overpressure required for dyke propagation were governed by the country rock permeability and strength, with pre-existing fractures playing a pivotal governing role. During this stage of dyke evolution significant amounts of exsolved gas …
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Mantle upwelling, melt generation, and magma transport beneath mid-ocean ridges
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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Terrestrial magma ocean solidification and formation of a candidate D" layer
… we investigate the solidification of early magma oceans on the Earth and the formation of a deep dense layer at the core-mantle boundary. We also study the concentrations and densities of the last layers of the solidified magma ocean and how they create a deep dense layer after solid-state …
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Intense Shallow Magma Sediment Mingling within Dikes at Guffey Butte Maar, Idaho
The interactions between magma and shallow unconsolidated sediments on the way to the surface influences the eruption behavior and products. Phreatomagmatic eruptions are a result of the interaction of magma and water or wet sediment and their deposits are evidence of this interaction. The relative …
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The Mercurian magma ocean, first crust, and implications for planetary formation mechanisms
… core, and by processing the mantle through a magma ocean, would produce a low-iron crust. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. The earliest crusts expected in a giant impact scenario are discussed in …
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