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 1173 for “"geochemical"”.
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Geochemical Flow Modeling
… of uranium roll-fronts could be reproduced using geochemical flow modeling. Under suitable conditions, selenium and arsenic mineralization occurs during roll-front genesis and that the positions of these trace metals are located immediately upstream and downstream, respectively, of the uranium …
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Pattern formation in geochemical systems.
Compositional patterns are extremely common in natural minerals. While, in many cases, variations in the solid mineral composition reflect the external changes in the environment at the time of the mineral formation, the role of self-organization is increasingly acknowledged. For example, in …
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Geochemical Aspects of Waste Disposal
The work began with an investigation of methods of determination of phenol in solution and was extended to investigate ways of rendering phenol harmless using chemical means applicable to conditions encountered at a waste disposal site. In addition the possibility of finding a catalyst which may …
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Geochemical studies of earth materials
Natural chalcopyrite-bearing fluid inclusions from the Red Mountain, Arizona, porphyry copper prospect have been used to experimentally document the movement of hydrogen into and out of fluid inclusions in quartz. Chalcopyrite daughter minerals in inclusions do not dissolve during heating studies …
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Geochemical characterization of endmember mantle components
This thesis uses trace elements and radiogenic isotope tracers to define elemental abundances in reservoirs of the Earth's mantle, including EM2 (the Enriched Mantle 2), as seen in the Samoan hotspot track, and DMM (the depleted upper mantle), which is sampled at mid-ocean ridges. Together these …
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Geochemical characerization of endmember mantle components
This thesis uses trace elements and radiogenic isotope tracers to define elemental abundances in reservoirs of the Earth's mantle, including EM2 (the Enriched Mantle 2), as seen in the Samoan hotspot track, and DMM (the depleted upper mantle), which is sampled at mid-ocean ridges. Together these …
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Geochemical Investigations of Respirable Particulate Matter
… reactor was used to evaluate two applications of geochemical methods to characterize the behavior of inhaled particles in the body. Dissolution rates of a well-characterized sample of powdered talc were measured in solvents that mimic fluids found in the human lung. These studies showed that …
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Geochemical Reactions in Unsaturated Mine Wastes
Although mining is essential to life in our modern society, it generates huge amounts of waste that can lead to acid mine drainage (AMD). Most of these mine wastes occur as large piles that are open to the atmosphere so that air and water vapor can circulate through them. This study addresses the …
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Geochemical Significance of Biomarkers in Paleozoic Coals
Diese Arbeit analysiert extrahierbares organisches Material von 40 paläozoischen Proben mit dem Ziel, Einblicke in die biochemische Evolution der Landpflanzen zu gewinnen. Zusätzlich wird der Zusammenhang zwischen sauerstoffhaltigen Verbindungen und den nichtfunktionalisierten aromatischen …
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Appalachian rhyolites--geochemical data concerning their origin.
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1972.
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Organic geochemical biosignatures in alkaline Hydrothermal ecosystems
The 13C content of microbial products are controlled by many factors, including the 13C content of the growth substrate, growth rate, the flux of carbon through various parts of the biochemical network, and the isotopic fractionation imposed by the enzymes of that network. We analyzed the 13C …
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Geochemical Evolution at White Island, New Zealand
… from crystallizing. The tectonic setting and geochemical characteristics of the magma body at White Island are similar to features observed in economic porphyry systems elsewhere. These data suggest that development of economic porphyry copper mineralization at White Island is likely.
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Geophysical and geochemical constraints on submarine volcanic processes
Submarine volcanic systems form new oceanic crust, host unique chemosynthetic ecosystems, concentrate rare metals, and provide a conduit for chemical transfer from the Earth's interior to hydrosphere. Although our understanding of submarine volcanoes has been historically limited due to their …
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Geochemical characterisation of Archaean granitoids in eastern Finland
The oldest rocks in Finland are the Archaean grey gneisses of eastern and northern Finland. The Archaean of the Karelian craton spans about 1000 Ma of crustal growth and evolution and forms the core of the Fennoscandian shield. The Karelian province is a complex patchwork of different rock types. …
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A geochemical analysis of municipal solid waste ash
Bulk chemical analysis of a combined municipal solid waste (MSW) bottom and fly ash from one facility showed most elements enriched over average soil abundances. Eleven minerals were identified using powder X-ray diffraction (XRD). Standard additions using XRD gave the following weight % minerals …
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Geochemical effects on natural convection in porous media
We describe a model of buoyancy-driven flow in a saturated reactive porous medium, the porosity and permeability of which evolve through precipitation and dissolution as a mineral is lost or gained from the pore fluid. We consider two scenarios: convection driven solely by solutally induced …
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EASTERN EQUATORIAL PACIFIC PRODUCTIVITY VIA TWO GEOCHEMICAL PROXIES
… Proposal 626) have been used as a reference for geochemical concentration parameters, as well as a comparison tool for productivity variations among the central and eastern sites. The central equatorial geochemistry results provided support for sea level changes driving paleoproductivity …
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