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Showing 1 to 20 of 48 for “"Mantle Plume"”.
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Radial Miscible Viscous Fingering of Icelandic Mantle Plume
The Icelandic plume, a major convective upwelling, has had a considerable influence on the geological evolution of the North Atlantic region. Direct manifestations of this major convective upwelling include positive residual depth anomalies and long wavelength free-air gravity anomalies, both of …
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Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics
… bathymetric and gravity anomalies at five plume-ridge systems to constrain crustal and mantle density structure at these prominent oceanic features. Numerical models are then used to explore the physical mechanisms controlling plume-ridge interaction and to place theoretical constraints on …
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Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.
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Magmatism and dynamics of continental breakup in the presence of a mantle plume
This thesis studies the dynamics of mantle melting during continental breakups by geophysical, geochemical, and numerical analyses. The first part focuses on the mantle melting and crustal accretion processes during the formation of the Southeast Greenland margin, on the basis of deep-crustal …
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Magmatism and dynamics of continental breakup in the presence of a mantle plume
This thesis studies the dynamics of mantle melting during continental breakups by geophysical, geochemical, and numerical analyses. The first part focuses on the mantle melting and crustal accretion processes during the formation of the Southeast Greenland margin, on the basis of deep-crustal …
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Insights into the location, nature and influence of mantle heterogeneity in the Galápagos mantle plume
… of the Earth's, highly heterogeneous, convecting mantle. Our view of the Earth's mantle is, however, partially obscured by processes that influence mantle-derived melts as they transition through the lithosphere (e.g. mixing, assimilation). Nevertheless, via careful consideration of the magmatic …
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The Evolution of the Galapagos Mantle Plume: From Large Igneous Province to Ocean Island Basalt
Mantle plumes are anomalously hot, narrow upwellings of mantle material that originate at the core-mantle boundary. As plumes rise they may form volumetrically large "heads" (~1000 km in diameter) with narrower (~100 km) "tails." Plume head melting is thought to form Large Igneous Provinces (LIPs), …
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Mantle melting processes: evidences from ophiolites, large igneous provinces, and intraplate seamounts
Melting processes in the mantle have a key role in plate tectonics and in the most colossal phenomena in the Earth, like large igneous provinces, mantle plume upwellings, and the constant growth of the planet's tectonic plates. In this study we use the geochemical and petrological evidence …
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Petrography and geochemistry of the Gross Spitzkoppe Igneous Complex Central-Western Namibia
… Mesozoic period. The magmatic event (Tristan mantle plume?) is characterised by bimodal epizonal emplacement of evolved melt fractions and mafic dyke swarms
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Visualizing and Understanding Tectonism and Volcanism on Earth and Other Terrestrial Bodies
… lithospheres and includes impact, plate, plume, cryo- and gravitational mechanisms. This dissertation is concerned with plate tectonics and plate/mantle plume interactions. Plate tectonics describes the mainly horizontal motion of lithospheric plates over the asthenosphere. Lithosphere is …
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Geochemical, Isotopic, and Mineralogical Characterization of the Frobisher Suite Mafic-Ultramafic Sills, Southern Baffin Island, Nunavut, with Implications for Metallogenic Potential
… melting occurred to differing degrees within a mantle plume head, at various depths below the Meta Incognita microcontinent at ca. 1900 Ma. A number of sills formed via injections of multiple, distinct magma types, some of which were influenced by subcontinent lithospheric mantle. Disseminated …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 2)
… represent the surface expression of the Comores mantle plume. New mineral and bulk-rock analyses, as well as selected rare earth element (REE), 87Sr/86Sr and 143Nd/144Nd compositions for lavas from three of the four main islands of the archipelago are presented. The alkaline lavas of the Comores …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 1)
… represent the surface expression of the Comores mantle plume. New mineral and bulk-rock analyses, as well as selected rare earth element (REE), 87Sr/86Sr and 143Nd/144Nd compositions for lavas from three of the four main islands of the archipelago are presented. The alkaline lavas of the Comores …
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The origin of the assymetry in the Iceland hotspot along the Mid-Atlantic ridge from continental breakup to present-day
… with 3D numerical models that simulate a mantle plume interacting with the evolving ridge system. Modeled maps of crustal thickness and plume influence indicate that asymmetrical influence along the ridge system is partially caused by the asymmetric ridge configuration relative to the …
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Understanding uplift of the Ethiopian Plateau from longitudinal profile analysis of the Blue Nile drainage system
… of correlation of <em>k<sub>sn</sub></em> with mantle tomography suggests that higher and lower <em>k<sub>sn</sub></em> values occur above low-velocity and high-velocity zones, respectively, indicating that thermal upwelling beneath the plateau linked to Afar mantle plume largely controls the …
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Understanding Non-Plume Related Intraplate Volcanism
… of intraplate volcanism are dominated by mantle plumes, but alternative explanations, such as adiabatic decompression triggered by lithospheric delamination, and edge driven convection (EDC), could be responsible for magmatism. This dissertation explores intraplate volcanic locations that …
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Melt generation in the Earth's mantle at Convergent Plate Margins
… effect on the melting behavior of the Earth's mantle. Two experimental studies (Chapters 1 and 2) of the melting behavior of mantle peridotite demonstrate that the forefathers of arc magmas are formed at extremely low temperatures in the mantle wedge at convergent plate margins in the presence …
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Testing the hypothesis of the slab-plume interaction on the formation of the Yellowstone hotspot system
… two main categories that involve either a deep mantle plume or only upper mantle processes. Recent seismic tomography images suggest the existence of hot mantle upwelling beneath the present-day Yellowstone, lending support to the plume hypothesis. However, the effect of the Farallon slab on the …
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Tracing mantle degassing along the East African Rift using He and C isotopes: a geospatial approach
… fluids and lavas were used as tracers to detect mantle-degassing across the East African Rift. From the literature, a database of R/Ra and δ13C-CO2 values was produced with accompanying isotopic and geochemical data. The data was filtered, removing samples of ambiguous origin, and samples heavily …
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Seismic anisotropy and mantle flow beneath Africa and Arabia
… phenomena involve edge-driven small-scale mantle convection and the thermal or dynamic effects of one or more mantle plumes. In this study we use continental scale shear-wave splitting (SWS) measurements to provide additional constraints on the various models of rifting, uplifting, and …
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