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 10 of 10 for “"carbon and oxygen isotopes"”.
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Sulfur, carbon, and oxygen isotopes of coexisting sulfides and carbonates in gas and oil seeps from the Gulf of Mexico
… bacterial disproportionation of sulfur (BDS), and BSR coupled with anaerobic oxidation of methane (BSR-AOM) occur in the Gulf of Mexico (GOM) at sites where hydrocarbon oil and gas seep through conduits to the seafloor. Thus far, no studies have measured the solid-phase sulfides from GOM seeps …
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Integrated approach to solving reservoir problems and evaluations using sequence stratigraphy, geological structures and diagenesis in Orange Basin, South Africa
Sandstone and shale samples were selected within the systems tracts for laboratory analyses. The sidewall and core samples were subjected to petrographic thin section analysis, mineralogical analyses which include x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive …
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Deciphering isotopic signals of monsoon-induced upwelling in foraminifera from the Western Arabian sea sediment trap
… sediment trap in the Arabian Sea during the 1986 and 1987 monsoons. Two of the species are non-spinose thermocline dwellers (Neogloboquadrina dutertrei, Globorotalia menardii) and two are spinose surface dwellers (Globigerinoides sacculifer, Globigerina bulloides). Individual tests were measured …
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An investigation of the tufa deposits at Ga-Mohana Hill in the Northern Cape, South Africa: palaeoenvironmental context for Late pleistocene and holocene human occupation in the Southern Kalahari
… area is poorly understood. Secondary calcium carbonates, including tufa, are common in the Kalahari, yet their palaeoclimate potential remains relatively unexploited. Tufa deposits at Ga-Mohana Hill, an archaeological site in the southern Kalahari, represent past water availability in a …
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Seasonal Influences on the Carbon-Water Relations in Ponderosa Pine Forests in the Northern Boundary of the North American Monsoon System
Climate models have projected that arid and semiarid lands will experience warmer and drier conditions for the next 100 years. For the last twenty years, the Southwestern US has been experiencing one of the worst droughts over the last century, not only threatening ecological systems but also the …
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Geochemistry of a volcanic hydrothermal system at Mount Spurr, Alaska
Mount Spurr is an ice and snow-covered andesitic volcano located at the northern extent of the Aleutian arc in south central Alaska. Previous workers have identified a prospective geothermal resource on the volcano's south side. This research aims to characterize more fully the hydrothermal system …
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Syn-sedimentary tectonostratigraphic influence and isotopic δ18O and δ13C characterization of the Kimmeridgian Akimpech Formation, Campeche-Chiapas Subbasin (Campeche Sound), offshore Mexico.
Carbonate reservoirs are notoriously heterogeneous, with variability driven by both depositional and diagenetic controls. In such reservoirs, conceptual models play an important role in generating understanding and predictive insights. Yet, predictions are only as good as the conceptual models. …
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Integrated approach to solving reservoir problems and evaluations using Sequence Stratigraphy, Geological Structures and Diagenesis in Orange Basin, South Africa"
… approach to evaluate reservoir rock quality and source rock potential is becoming increasingly important in petroleum geology. This approach was employed to unravel the reason for variable reservoir quality of sandstones and evaluation of source rock potential of shale intervals of Orange …
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Mineralogy and geochemistry of the non-sulfide Zn deposits in the Sierra Mojada district, Coahuila, Mexico
… deposits, "non-sulfide Zn" (NSZ) deposits, and a Pb carbonate deposit hosted by Upper Jurassic to Lower Cretaceous carbonates. This study focuses on the two non-sulfide Zn deposits, the Smithsonite Manto and the Iron Oxide Manto, that occur south of the San Marcos fault. The Smithsonite …
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Early Palaeogene planktic foraminiferal assemblages in Australasian sequences: links to past changes in climate and carbon cycling
… as significant perturbations in climate and carbon cycling marked this time interval clearly evidenced by major turnovers in biota, and profound variations in global carbon isotope (δ^13C) records. The most prominent of these δ^13C changes include an interval of extreme ^13C-enrichement, …