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.
Results
Showing 1 to 19 of 19 for “"Mantle processes"”.
-
Geochemistry of the Northern Izu-Bonin arc: implications for crustal recycling and mantle processes
… the exchange of elements between flux<br/>and mantle that lead to the creation of arc magmas. These calculations allow the changes in<br/>fluid flux from the slab and the variations of mantle composition to be correlated with the<br/>variations in across-arc geochemistry.<br/>All of the …
-
A study of the diamonds, diamond inclusion minerals and other mantle minerals from the Swartruggens Kimberlite, South Africa
… a 'revolution' in the scientist's perception of mantle processes, particularly that regarding diamond formation. Kramers (1977) fIrst clearly recognised the ancient origin of diamonds from his studies of composited sulphide inclusions. However, it was not until mid-Archean ages were obtained from …
-
Evaluating mantle and crustal processes using isotope geochemistry
… distinct reservoirs such as the Earth's crust, mantle and core. In this dissertation the strategy has been to work on a broad range of topics to evaluate crustal and mantle processes. This study presents Re-Os systematics to constrain the composition, formation and age of the lower continental …
-
The lattice preferred orientation of olivine in Beni Bousera Ultramafic Massif, Morocco
The roll of melt in deformation of the mantle is important for understanding mantle processes and evolution. The Beni Bousera Ultramafic Massif, northern Morocco, shows petrologic evidence that melt was an important part of its history. The massif, dominantly composed of spinel lherzolite with …
-
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 …
-
Climatic and geodynamic influences on ocean island geomorphology
… erosion and the contribution of lithosphere and mantle processes to surface deformation at hotspots. Through physically-based modeling, analysis of remote sensing and geochronologic data, and field measurements, this thesis examines (1) the dominant mechanisms of vertical motion in the Hawaiian …
-
Petrogenesis of kimberlites from South Africa and lamproites from Western Australia and North America
… and North America are relatively unfractionated mantle-derived igneous rocks, situated on or close to ancient cratonic areas. They are characterised by high trace element contents, while the range in N d and Sr isotopes encompasses much of that reported for various upper and lower crustal rocks. …
-
Testing the Utility of S Receiver Function Analysis For Mapping Seismic Discontinuities In the Sierran Lithosphere
… of overall intermediate crust from a mafic mantle, processes that have long puzzled geologists (Bird et al., 1979; Zandt et al., 2004). In order to better understand this enigmatic process, the Sierra Nevada EarthScope Project deployed a two phase, broadband seismic array consisting of 95 …
-
The relationship between plate curvature and elastic plate thickness : a study of the Peru-Chile Trench
… the trench do not appear to be linked to upper mantle processes which impose the dip at greater depth. Finally, we consider the possibility that the elastic thickness of the lithosphere would be reduced for trenches that are highly arcuate in map view, again due to inelastic yielding. If such a …
-
Primitive magmas of the Earth and Moon : a petrologic investigation of magma genesis and evolution
… major physical evidence used to determine the mantle potential temperature of the Archean. Chapter 2 uses phase equilibrium experiments investigate the origin of the Apollo 15 green glasses from the Moon. Garnet-lherzolite saturated experiments are used to calibrate a melting algorithm used to …
-
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 …
-
GEOCHRONOLOGY, GEOCHEMISTRY, AND TECTONIC CHARACTERIZATION OF QUATERNARY LARGE-VOLUME TRAVERTINE DEPOSITS IN THE SOUTHWESTERN UNITED STATES AND THEIR IMPLICATIONS FOR CO2 SEQUESTRATION
… Travertines are surface expressions of dynamic mantle processes related to the tectonic setting. This dissertation includes four chapters that focus on different aspects of travertine formation and their scientific value. They are excellent, although underestimated, diagnostic tools for …
-
Unveiling the lithospheric and mantle dynamic controls on Antarctic topography
… influenced by spatially and temporally variable mantle dynamics. This study uses an interdisciplinary approach to probe the present-day crust and mantle beneath Antarctica. First, observed bathymetry and topography in the oceanic and continental realms are corrected for isostatic effects to …
-
Petrogenesis of the Eshowe melilitites
… 200my. This magmatism was probably related to mantle processes responsible for the continental fragmentation and was controlled by a fluctuating mantle thermal regime. The Eshowe melilitites intrude an area of attenuated crust in an essentially rift valley setting. Petrological, and chemical …
-
Magma genesis beneath active continental rifts
… continental rift systems on Earth, but the processes governing rift dynamics remain controversial. The large volume and distinct chemistry of Cenozoic rift-related lavas, combined with geophysical evidence for low-density mantle underlying both rifts, have traditionally been interpreted as …
-
Magmatic processes at basaltic volcanoes: insights from the crystal cargo
… transported between reservoirs, from the upper mantle and through the crust, leading to melt mixing, reactions and volatile exsolution. Basaltic volcanic systems are fed by primitive melts, and due to the rapid ascent of melts and short magma storage times, these volcanoes provide the best means …
-
Evaluating mantle and crustal processes using isotope geochemistry
… distinct reservoirs such as the Earth's crust, mantle and core. In this dissertation the strategy has been to work on a broad range of topics to evaluate crustal and mantle processes. This study presents Re-Os systematics to constrain the composition, formation and age of the lower continental …
-
New Experimental Data for a Re-Calibration of the Fe-Ti Oxide Thermo-Oxybarometers
… information, e.g. on redox states in the Earth’s mantle, processes in magma chambers, or the crystallisation conditions of lunar or martian basalts. Current thermodynamic formulations of the Tmt-Ilmss thermo-oxybarometer (Andersen & Lindsley, 1988; Ghiorso & Sack, 1991) fail to reproduce …
-
LATERALLY HETEROGENEOUS SEISMIC ANISOTROPY INVESTIGATED BY SHEAR WAVE SPLITTING ANALYSES
… property of the Earth’s crust and upper mantle. In this study, we utilize the shear wave splitting technique to investigate the piercing-point-dependent azimuthal anisotropy beneath the northeastern edge of the Sichuan Basin in central China, and the spatial and temporal variations of …