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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 29 for “"Magma chambers"”.
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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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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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Controls of Melt Genesis and Evolution at Buldir Volcano in the Western Aleutian Island Arc
… removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation versus source variability in the …
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Seismic and gravitational studies of melting in the mantle's thermal boundary layers
… to constrain the location and depth of axial magma chambers at the Endeavour Segment of the Juan de Fuca spreading ridge, and then correlates these magma chamber locations with features of the hydrothermal heat extraction system in the upper crust such as microseismicity caused by thermal …
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Seismic and gravitational studies of melting in the mantle's thermal boundary layers
… to constrain the location and depth of axial magma chambers at the Endeavour Segment of the Juan de Fuca spreading ridge, and then correlates these magma chamber locations with features of the hydrothermal heat extraction system in the upper crust such as microseismicity caused by thermal …
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Petrogenetic Relationship of the Postcaldera Eruptions of Mount Mazama, Crater Lake, Oregon; Evolution of a Sub-volcanic Magma Chamber Following a Large Silicic Eruption
… formed a dome (Bacon et al., 2002). How magmatic systems evolve following a shallow, relatively large silicic eruption is the focus of this study. In situ geochemical analysis coupled with high-resolution textural images of plagioclase crystals in the four postcaldera volcanic edifices …
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Order and chaos in the olivine underworld: two mechanisms for the formation of basal olivine layers
<p>Recent debate has questioned the efficiency of magma differentiation in basaltic magma chambers (Marsh, 2013). As a result, petrologists are increasingly inclined to interpret olivine cumulate layers in small intrusive bodies as separately injected slurries, as opposed to the result of in-situ …
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Element fractionation in the petrogenesis of ocean island basalts
… processes, involving residence in deep (>4kbar) magma chambers, that are inferred to persist for at least 30ka. The basanites show geochemical variations related to differences in the degree of partial melting, that are estimated to be between 0.3-2%. Rare earth element (REE) modelling suggests …
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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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Geochemistry and petrogenesis of the Catoctin Volcanic Province, central Appalachians
… represents a sequence of rift related tholeiitic magmas erupted during late Precambrian opening of the Iapetus ocean basin. Three transects have been mapped across the province in northern Virginia in order to demonstrate that there is a mappable stratigraphy and to provide a framework upon which …
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Petrogenetic Processes Characterizing the Mount Bachelor, Oregon Magmatic System: Open- versus Closed-System Processes
… with time, but a detailed assessment of magma chamber processes has not been conducted. To gain a more thorough understanding of the magmatic processes that have contributed to the observed compositional evolution, this study focuses on one of four eruptive episodes, specifically episode …
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The record of magma storage conditions in mineral compositions below a glacial to ice-free Askja volcano, Iceland
… and textures from basaltic lavas to reconstruct magma chamber conditions before, during and after glaciation. In this study, 36 lava flow and gabbro xenolith samples were collected from seven separate units: two glacial, the Early Holocene, and four historical. These samples were analyzed along …
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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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The geochemistry, kinematics and geodynamics of the Gannakouriep dyke swarm
… was initiated as a series of low level crustal magma chambers which subsequently gave rise to a series of dyke complexes that comprise the Gannakouriep dyke swarm. The geochemical variability between individual dyke complexes across the entire swarm is negligible; only slight differences being …
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Numerical simulations of magma chamber dynamics at Campi Flegrei, and associated seismicity, deformation and gravity changes
… by volcanic monitoring network and shallow magma processes is a crucial headway for the comprehension of volcanic processes and a more realistic evaluation of the associated hazard. This question is very relevant at Campi Flegrei, a volcanic quiescent caldera immediately north-west of Napoli …
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The nature and origin of fine-scale sea-floor relief
… is suggested to be controlled by the width of magma chambers at faster spreading centers and the extent of viscous forces at deeply rifted slow spreading centers.
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The geochemistry, mineralogy and igneous petrology of some fracture zone basalts from the southern Mid-Atlantic Ridge
… are used to identify 4 distinct parental magmas. Consideration of Fe-Mg partitioning between olivine and the host rock is used to identify possible liquid compositions. Such considerations indicate that the olivine phyric Group C sample represent olivine ( + minor Cr-spinel) enriched …
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