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 13 of 13 for “"geochemical variations"”.
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Mineralogic and Geochemical Variations within the Old Hickory Heavy Mineral Sand, Sussex and Dinwiddie Counties, Virginia
… generations of heavy mineral deposition. The variations in grain size, angularity, and rutile content are likely to be mappable and may prove useful in continuing stratigraphic studies, and in distinguishing separate ore zones.
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Imaging and interpreting seismic heterogeneity in the North American lithosphere
… how they are influenced by thermal and geochemical variations. In this Thesis I jointly interpret inverse modeling of seismic data and forward modeling of chemical and thermodynamic data in order to investigate the origins of seismic heterogeneity within the cratonic lithosphere. I …
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Geology of the Bottle Lake Complex, Maine
… in the granite of Whitney Cove. Both display geochemical variations identifying the respective core facies as the least differentiated zones compared to the rims. On the basis of field relations the relative sequence of intrusion is established between the two intrusives, but geochronologic …
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Geologic and Geochemical Characterization of Cross-Communication Potential within the Northern Edwards Aquifer System, Texas
… the structural, hydrogeological and geochemical variations within the highly karsted region. However, the Northern Segment of the Edwards Aquifer primarily consists of undeveloped rural land, and is therefore lacking sufficient studies to fully understand the structural, …
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Origin of geochemical heterogeneity in the mantle : constraints from volcanism associated with Hawaiian and Kerguelen mantle plumes
… compositions and the processes that created the geochemical heterogeneity within the mantle. Kerguelen and Hawaii are two long-lived mantle plumes and lavas associated with them have very different geochemical characteristics. In this thesis I studied the geochemical compositions of the lavas …
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Element fractionation in the petrogenesis of ocean island basalts
… to persist for at least 30ka. The basanites show geochemical variations related to differences in the degree of partial melting, that are estimated to be between 0.3-2%. Rare earth element (REE) modelling suggests clinopyroxene, rather than garnet control during melting, contrary to expectations …
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Multi-Scale Mapping of Diagenetic Processes in Sandstones Using Imaging Spectroscopy: A Case Study of the Frontier Formation (Wyoming, U.S.A.) and the Utrillas Formation (Burgos, Spain)
… imaging to analyze lateral and vertical geochemical variations and quantify facies and diagenetic mineral abundances. The study was carried out on the delta front deposits of Wall Creek Member of the Cretaceous Frontier Formation, Wyoming and on the upper member of the Utrillas Formation, …
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Cooling and crystallization of komatiite flows.
… from the bulk liquid, and whole-rock geochemical variations within flows by crystal fractionation of highly magnesian olivine. The high chromium content of olivine is of mineralogical and technological interest, and is due to two substitutional mechanisms: $\sp{\lbrack …
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The Hydrology And Geochemistry Of Urban And Rural Watersheds In East-Central Missouri
… than one year to document their hydrologic and geochemical character. Urban streams were characterized by flashier responses to storm perturbations and had reduced baseflow components compared to rural streams. Rural streams had smaller hydrologic and geochemical variations, higher baseflow, and …
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Stratigraphy and petrogenesis of the Parana continental flood basalts, southern Brazil
… distinct magma types is proposed, based on new geochemical data plus a review of literature analyses, which retains the previously established overall classification into high and low-Ti varieties; <i>viz</i>. high-Ti (> 2 wt%) - (Urubici, Pitanga, Paranapanema}, low-Ti (< 2 wt%) - (Gramado, …
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Characterisation of ocean island basalt sources : St. Helena
… framework is developed to illustrate temporal geochemical variations over 2 Ma of subaerial activity. This is accomplished in conjunction with a detailed field study of the SHRS by Baker(1968) which is shown to be largely accurate. It is demonstrated that ascending magma batches are …
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Lithofacies Determination in the Willesden Green and South Pembina Duvernay Formation: Creation, Characterization, and Correlation
… well logs and can be further related to geochemical data, elastic properties, elastic property-based brittleness indices, mineralogical brittleness indices, and basic source rock data. A sedimentological assessment of seven wells was performed and the resultant data used to define the …
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The geochemistry and petrology of the Rodrigues Ridge (Western Indian Ocean)
… showed them to be 8-10 My, with no systematic variations with longitude. All samples recovered from the Rodrigues Ridge were olivine and plagioclase phyric with traces of chrome spinel. Only the most western site contained any phenocryst clinopyroxene. Phenocryst olivine was in the range …