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Social and Behavioral Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

2008

Physical Sciences and Mathematics

Georgia State University

Articles 1 - 6 of 6

Full-Text Articles in Social and Behavioral Sciences

Timing And Characterization Of The Change In The Redox State Of Uranium In Precambrian Surface Environments: A Proxy For The Oxidation State Of The Atmosphere, Gerald D. Pollack Dec 2008

Timing And Characterization Of The Change In The Redox State Of Uranium In Precambrian Surface Environments: A Proxy For The Oxidation State Of The Atmosphere, Gerald D. Pollack

Geosciences Dissertations

The redox-sensitive geochemical behavior of uranium permits the use of Th/U ratios as a geochemical proxy for the oxidation state of the atmosphere and oceans during sedimentary processes. Due to the effects of post-depositional uranium mobility on Th/U ratios during events involving oxygenated fluids, direct measurements of Th/U ratios are often misleading, but the whole rock Pb isotope composition may be used to determine a sample¡¦s apparent time-integrated Th/U ratio (ƒÛa) and the timing associated with the onset of the U-Th-Pb geochemistry. Rare earth element (REE) concentrations were determined by isotope dilution mass spectrometry to evaluate the influence of multiple …

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Improving Summer Drought Prediction In The Apalachicola-Chattahoochee- Flint River Basin With Empirical Downscaling, John Robert Dean Jul 2008

Improving Summer Drought Prediction In The Apalachicola-Chattahoochee- Flint River Basin With Empirical Downscaling, John Robert Dean

Geosciences Theses

The Georgia General Assembly, like many states, has enacted pre-defined, comprehensive, drought-mitigation apparatus, but they need rainfall outlooks. Global circulation models (GCMs) provide rainfall outlooks, but they are too spatially course for jurisdictional impact assessment. To wed these efforts, spatially averaged, time-smoothed, daily precipitation observations from the National Weather Service cooperative network are fitted to eight points of 700 mbar atmospheric data from the NCEP/NCAR Reanalysis Project for climate downscaling and drought prediction in the Apalachicola-Chattahoochee-Flint (ACF) river basin. The domain is regionalized with a factor analysis to create specialized models. All models complied well with mathematical assumptions, though the …

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A Comparative Study Of The Badger Pass Igneous Intrusion And The Foreland Volcanic Rocks Of The Mcdowell Springs Area, Beaverhead County, Montana: Implications For The Local Late Cretaceous Sequence Of Events, Brookie Jean Gallagher Apr 2008

A Comparative Study Of The Badger Pass Igneous Intrusion And The Foreland Volcanic Rocks Of The Mcdowell Springs Area, Beaverhead County, Montana: Implications For The Local Late Cretaceous Sequence Of Events, Brookie Jean Gallagher

Geosciences Theses

Intermediate igneous rocks exposed in the Badger Pass area and 3.5 km away in the McDowell Springs area of Beaverhead County, Montana, previously mapped as Cretaceous intrusive (Ki), and Cretaceous undifferentiated volcanics (Kvu) respectively, exhibit little geochemical variation. Trace element, and lead isotope analyses provide strong evidence allowing for a single source. REE patterns, obtained through ID-ICP-MS, are essentially identical. Mineral/melt Eu analyses reveal that Eu behaved predominantly as a divalent cation, refuting an earlier study asserting that trivalent Eu dominated. Data suggest rocks were formed under low oxygen activity conditions, not oxidizing conditions as previously reported. Geochemical data combined …

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Estimation Of Hydraulic Properties Of The Shallow Aquifer System For Selected Basins In The Blue Ridge And The Piedmont Physiographic Provinces Of The Southeastern U.S. Using Streamflow Recession And Baseflow Data, Farshad Baloochestani Apr 2008

Estimation Of Hydraulic Properties Of The Shallow Aquifer System For Selected Basins In The Blue Ridge And The Piedmont Physiographic Provinces Of The Southeastern U.S. Using Streamflow Recession And Baseflow Data, Farshad Baloochestani

Geosciences Dissertations

The objectives of this research are to measure the aquifer properties (S, T, and K) of selected watersheds delineated to the U.S. Geological Survey gauging stations using streamflow recession and baseflow data and to describe the relations among the properties of shallow aquifers and the physical properties of the basins, such as slope, regolith type and thickness, and land use type. Geographic Information System (GIS) techniques are utilized to investigate critical physiographic controls on transmissivity and storage coefficients on a regional basis. Moreover, the effect of evapotranspiration on recession index is illustrated. Finally, a detailed quantitative comparison of results for …

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A Multitemporal Analysis Of Georgia's Coastal Vegetation, 1990-2005, Charles, Iii F. Breeden Apr 2008

A Multitemporal Analysis Of Georgia's Coastal Vegetation, 1990-2005, Charles, Iii F. Breeden

Geosciences Theses

Land and vegetation changes are part of the continuous and dynamic cycle of earth system variation. This research examines vegetation changes in the 21-county eco-region along coastal Georgia. The Advanced Very High Resolution Radiometer (AVHRR) with Normalized Difference Vegetation Index (NDVI) data is used in tandem with a Principal Component Analysis (PCA) and climatic variables to determine where, and to what extent vegetation and land cover change is occurring. This research is designed around a 16 year time-series from 1990-2005. Findings were that mean NDVI values were either steady or slightly improved, and that PC1 (Healthiness) and PC2 (Time-Change) explained …

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Recollections Of Gilbert F. White In Colorado, Risa Palm Jan 2008

Recollections Of Gilbert F. White In Colorado, Risa Palm

Geosciences Faculty Publications

No abstract provided.

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