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 16 of 16 for “"Nd Isotopes"”.
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Using Nd Isotopes to understand changes in continental weathering flux in Mid-Pennsylvanian (Desmoinesian) carbonate cycles
… of study on Phanerozoic sedimentary deposits indicates that changes in Earth's orbital parameters are one of the main drivers of climate change on the 104-105 yr time scales, however understanding the relationships between climate change on coeval marine and continental deposits is difficult …
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A geochemical profile through the Uitkomst Complex on the farm Slaaihoek, with special reference to the platinum-group elements and Sm-Nd isotopes
… It is situated on the farms Uitkomst 541JT and Slaaihoek 540JT, about 25 km north of Badplaas and 50 km east of the eastern limb of the Bushveld Complex in the Mpumalanga province of South Africa. The intrusion plunges between 8 to 10º to the northwest with an established length of 12 km and …
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Investigating sediment size distributions and size-specific Sm-Nd isotopes as paleoceanographic proxy in the North Atlantic Ocean: reconstructing past deep-sea current speeds since Last Glacial Maximum
… in the North Atlantic can be related to modern and past Atlantic Meridional Overturning Circulation (AMOC) flow speed, particle size distributions (weight%, Sortable Silt mean grain size) and grain-size separated (0–4, 4–10, 10–20, 20–30, 30–40 and 40–63 µm) Sm-Nd isotopes and trace element …
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Marine cycling of neodymium in the South Atlantic and the Southern Oceans
Neodymium (Nd) isotopes have been used as a proxy to trace both modern and palaeo-ocean circulation of the deep ocean which is an important factor controlling the climate. Although there has been widespread utilisation of Nd isotopes as a proxy, the marine cycling of Nd is not fully understood. …
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Ocean circulation and carbon cycle dynamics in the Pacific Southern Ocean during Late Pleistocene interglacials
… ocean basins, driving Antarctic Bottom Water and Antarctic Intermediate Water formation and providing the major return path of Circumpolar Deep Water (CDW) to the ocean surface. The Pacific Ocean is the largest aquatic carbon reservoir and having a strong leverage on atmospheric CO2 …
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Geochemistry, Thermochronometry, Petrogenesis, and Geometry of Igneous Dikes in Central Arkansas: Implications for Mississippi Embayment Evolution
… the Cambrian Mississippi Valley Graben (MVG) and serves as a natural laboratory for extensional tectonics. The Arkansas Alkaline Province (AAP) lies along the ME’s western border in central Arkansas and was emplaced in the mid-Cretaceous Period as a suite of intrusive bodies. The relationship …
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Tectonics of the southern Annapurna Range, central Nepal Himalaya
… however, limiting the accuracy of dynamic and kinematic models. For example, the location of a mega-thrust now exposed in the interior of the range, the Main Central thrust (MCT), is only approximately known across much of the Himalaya. Both because the MCT accommodated at least 150 …
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Tectonic implications of mantle source changes recorded by Eocene-Oligocene basalts from the Dillon volcanic field southwest Montana (USA)
… tectonics, within the northern Rocky Mountains and accordingly, also present across the North American Cordillera. The Dillon volcanic field is composed of lavas and intrusives that crop out across southwestern Montana, but most prominently in the Gravelly Range, where they define multiple …
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U-Th-Pb fractionation in selected carbonate and silicate systems
V-Th-Pb fractionation trends, and the associated variations in Pb-isotopes, provide important constraints on the nature, and age, of a wide range of geological processes. This thesis presents three detailed case studies from a carbonatite intrusive complex, lower crustal granulite xenoliths, and …
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Geochemical and Geochronological Constraints on the Origin and Evolution of Rocks in the Active Woodlark Rift of Papua New Guinea
… that is applicable to developing a better understanding of the geologic record. One such area of the World is Papua New Guinea, much of which is situated in an active and transient plate boundary zone. The focus of this PhD research is to develop a better understanding of rocks in the active …
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Petrology and geochemistry of the diamondiferous K-richteriteand leucite-bearing Kareevlei Kaapvaal lamproite
The Kareevlei diamond mine is the first mine on the evolved leucite-bearing Kaapvaal lamproite. These rock types have generally been believed to be non-diamondiferous or at least sub-economic and as a result, their petrogenesis has remained poorly constrained as the exploration programs focused …
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Evaluating mantle and crustal processes using isotope geochemistry
Geochemical studies are fundamental for understanding how the dynamic Earth works and evolves. These studies place constraints on the composition, formation, age, distribution, evolution and scales of geochemically distinct reservoirs such as the Earth's crust, mantle and core. In this dissertation …
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The isotope geochemistry of abyssal peridotites and related rocks
… of the formation of the Earth's oceanic mantle and crust, using a variety of geologic techniques, principally major elements, radiogenic isotopes and trace elements, but including petrography, mineral chemistry, x-ray diffraction, seafloor geomorphology, and analysis of the tectonics of fracture …
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A geochemical study of metasomatised peridotite and marid nodules from the Kimberley pipes, South Africa
… a large collection of metasomatised peridotite, and MARIO (Mica-Amphibole-ButileIlmenite-Qiopside) xenoliths from the Kimberley pipes, with the aim of obtaining an improved understanding of enrichment processes operating in the sub-continental lithospheric mantle. The metasomatised peridotite …
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Neotectonic evolution of Grand Canyon : interaction between volcanism, river incision, epeirogenic uplift, and faulting
… volcanism, river incision, epeirogenic uplift, and faulting on the landscape evolution of the Grand Canyon region. In the first chapter the migration of increasingly asthenospheric basaltic volcanism is used to constrain lithospheric modification of the Colorado Plateau margins. Buoyancy …