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 81 for “"isotope geochemistry"”.
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Boron isotope geochemistry
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institution, 1986.
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Evaluating mantle and crustal processes using isotope geochemistry
… of the mantle heterogeneities, and uses U-series isotope to constrain geodynamic parameters, such as the upwelling velocities and porosities of mantle plumes. The lower continental crust plays a pivotal role in understanding the composition and evolution of the continental crust and the …
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Stable isotope geochemistry of nitrogen in marine particulates
Isotope studies of nitrogen and carbon were undertaken to investigate the fate of particulate organic matter (POM) during its residence in the water column and after deposition on the seafloor. The processes focused on were water-column transformations and sedimentary diagenesis. Sampling sites …
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Evaluating mantle and crustal processes using isotope geochemistry
… of the mantle heterogeneities, and uses U-series isotope to constrain geodynamic parameters, such as the upwelling velocities and porosities of mantle plumes. The lower continental crust plays a pivotal role in understanding the composition and evolution of the continental crust and the …
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Stable isotope geochemistry of nitrogen in marine particulates
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983.
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The isotope geochemistry of abyssal peridotites and related rocks
… 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 zones. The first chapter is an introduction to the problems to be addressed in this work. …
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The isotope geochemistry of abyssal peridotites and related rocks
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1993.
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Geology and isotope geochemistry of the Beaver-Temiskaming Silver Mine, Cobalt, Ontario
… temperatures were about 210-240°C (oxygen isotopes in silicates), 211-258°C (arsenopyrite composition) and 130-227°C (coexisting sulphides). Carbonate isotopic data were reset by meteoric water. Connate waters, interpreted from fluid inclusion data, equilibrated with Archean sulphide-rich …
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The isotope geochemistry of uranium: Igneous petrology, ore deposits, and groundwater contamination
This study applies high precision 238U/235U measurement techniques two three geologic settings: basalt differentiation, uranium ore genesis, and the remediation of a uranium-contaminated groundwater system. In the latter two cases, 238U/235U is used as a tracer of uranium reduction. 238U …
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The oxygen, carbon & hydrogen isotope geochemistry of the Phalaborwa Complex, South Africa
… studies on multi-mineral oxygen and hydrogen isotopes or multi-rock carbonate carbon isotope data for the Phalaborwa Complex. These isotope systems are useful for identifying mineral disequilibrium and alteration, analyzing contamination and constraining the mantle source. Previous work has …
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Helium isotope geochemistry of oceanic volcanic rocks : implications for mantle heterogeneity and degassing
The concentrations and isotopic compositions of helium have been measured in a number of mantle derived oceanic basalts. The goal of this research is to use the helium isotopic systematics to constrain the nature and origin of mantle heterogeneity in the oceanic mantle. Studies of helium …
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Helium isotope geochemistry of oceanic volcanic rocks : implications for mantle heterogeneity and degassing
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982.
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Investigating nitrate attenuation in an urban stream using stable isotope geochemistry and continuous monitoring
Urbanization affects in-stream biogeochemical processes that control nutrient export. Attempts to restore urban streams will not be successful unless the biological and physical controls on water quality are thoroughly understood. The objective of this study was to identify the relative influences …
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Stable Isotope Geochemistry and Paleohydrology of the Poison Strip Sandstone, Early Cretaceous, Eastern Utah
The Poison Strip Sandstone Member is a unique unit in the early Cretaceous Cedar Mountain Formation of eastern Utah. A previous chemostratigraphic study of the Poison Strip Sandstone at the Ruby Ranch Road (RRR) section east of Green River, Utah produced a noteworthy dataset with interesting δ18O …
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Stable isotope geochemistry of the Okenyenya igneous complex, Namibia : constraints on contamination and fluid interaction
… suite, are consistent with the attainment of isotope equilibrium and largely closed system conditions. The majority of the temperatures calculated by conventional mineral-pair thermometers are spurious, as a result of oxygen isotope diffusion during slow cooling. Closure temperatures for …
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Helium and lead isotope geochemistry of oceanic volcanic rocks from the East Pacific and South Atlantic
… source regions and volcanic magmas. He and Pb isotopes were measured in glassy basalts from young seamounts in the East Pacific, and in phenocrysts and corresponding whole rocks, respectively, from the island of st. Helena. He isotopes were also measured in glassy mid-ocean ridge basalts from …
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Paleogeography of Western North America: Insights from Detrital Zircon U-Pb Geochronology and Hf Isotope Geochemistry
… techniques including U-Pb geochronology and Hf isotope geochemistry of detrital zircons, as well as, geologic mapping and paleocurrent analysis. The Neoproterozoic through Pennsylvanian Yukon-Tanana terrane (YTTs) in the Coast Mountains of southeastern Alaska, the Cretaceous through Eocene …
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Mercury stable isotope geochemistry as a tool for tracing sources and chemical transformations in the environment
… and artisanal gold and silver mining. Hg stable isotope ratios have been developed since the early 2000s in order to understand Hg cycling in the environment. The three studies reported in this dissertation aim at developing Hg isotope ratios as tools for source apportionment, identifying Hg …
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Helium and lead isotope geochemistry of oceanic volcanic rocks from the East Pacific and South Atlantic
… source regions and volcanic magmas. He and Pb isotopes were measured in glassy basalts from young seamounts in the East Pacific, and in phenocrysts and corresponding whole rocks, respectively, from the island of St. Helena. He isotopes were also measured in glassy mid-ocean ridge basalts from …
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