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Full-Text Articles in Earth Sciences
Water Sourcing Strategies Of Highly Resilient Vegetation In Desert Soils: Stable Isotope Analysis Of A Northern Chihuahuan Desert Ecosystem, Hayden Eleanor Thompson
Water Sourcing Strategies Of Highly Resilient Vegetation In Desert Soils: Stable Isotope Analysis Of A Northern Chihuahuan Desert Ecosystem, Hayden Eleanor Thompson
Open Access Theses & Dissertations
Plant water use strategies and water transport dynamics are important for understanding ecosystem productivity and soil-vegetation-atmosphere interactions within an environment (Li et al., 2007). Recent research using stable isotope analysis in wet and humid climates has found that vegetation uses tightly particle-bound water stored in the soil that does not participate in translatory flow (Brooks et al., 2010; Goldsmith et al., 2011; McDonnell 2014). In arid and semi-arid deserts of the United States, highly resilient vegetation, such as the Honey Mesquite (Prosopis glandulosa) and the Creosote shrub (Larrea tridentata), exhibit some degree of activity year-round despite limited water availability during …
Ductile Deformation In The Central Panamint Mountains - A Multi-Disciplinary Approach To A Multi-Dimensional Problem., Tai Antonia Subia
Ductile Deformation In The Central Panamint Mountains - A Multi-Disciplinary Approach To A Multi-Dimensional Problem., Tai Antonia Subia
Open Access Theses & Dissertations
This study provides new insights into the geometry and timing of ductile, syn-metamorphic structures in the central Panamint Mountains of eastern California. The study focused on Surprise Canyon, where exposures of Meso- to Neoproterozoic miogeocline rocks, reworked crystalline basement, and syn-metamorphic granitoids record fabric overprints indicative of at least two distinct dynamo-thermal metamorphic events. Prograde metamorphism at greenschist and amphibolite metamorphic facies conditions occurred during Early Jurassic plutonism based on deformation of a dioritic pluton with a U-Pb date reported here of 175.6 ± 3.2 Ma. Mid Jurassic deformation (D1) generated the main continuous cleavage in the rocks (S1) as …
Gypsum, Calcite, And Dolomite Caprock Fabrics And Geochemistry From The Gypsum Valley Salt Diapir, Paradox Basin, Southwestern Colorado, Kevin Lerer
Open Access Theses & Dissertations
Caprocks are found on top of or in a lateral position relative to salt diapirs. The caprocks predominantly comprise sulfate minerals such as anhydrite or gypsum, which presumably accreted during the dissolution of salt from evaporite sediments. In some cases, the sulfate minerals are replaced by carbonate minerals, referred to as "carbonate caprock". Carbonate caprocks associated with salt diapirs are important because they can act as reservoirs or conduits for hydrocarbons, and because they can be easily misidentified as carbonate lithologies belonging to the stratigraphy of the sedimentary sequences adjacent to the diapir, which can jeopardize the accurate interpretation of …
Genesis Of Unique Carbonate Fans In A Pre-Salt Reservoir Analogue, Indio Mountains, West Texas, Andre Llanos
Genesis Of Unique Carbonate Fans In A Pre-Salt Reservoir Analogue, Indio Mountains, West Texas, Andre Llanos
Open Access Theses & Dissertations
Hydrocarbon exploration in pre-salt sediments of rift basins on the South Atlantic Margin have proven to be successful major oil plays. Located on the western margin of the rift, the Brazilian pre-salt reservoirs of the Santos, Campos, and Espirito Santo Basins are hosted by lacustrine/marine-influenced carbonates that comprise laterally extensive, laminated microbialite facies. The Indio Mountains, located in West Texas, provide well-exposed outcrops of Lower Cretaceous marine and non-marine rift basin strata that can be considered a reservoir-analog to the South Atlantic Margin pre-salt facies. Of particular interest for hydrocarbon exploration are unique carbonate features that have been discovered in …
Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete
Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete
Open Access Theses & Dissertations
Copper isotopes may prove to be a useful tool for investigating bacteria-metal interactions recorded in natural waters, soils, and rocks. However, experimental data that constrain Cu isotope fractionation in biologic systems are limited and unclear. In this study we utilized Cu isotopes (65Cu) as a tool to investigate Cu-bacteria interactions, including surface adsorption and intracellular incorporation. Experiments were conducted with individual Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacterial species as well as with bacterial consortia from several natural environments. Adsorption experiments were conducted with live or dead cells over the pH range 2.5 to 6. Surface adsorption of Cu …