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Showing 1 to 19 of 19 for “"mineral weathering"”.
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Microbial and Chemical Zonation and Mineral Weathering in the Middendorf Aquifer, South Carolina
… of acid as CO2, but reaction of groundwater with minerals in the aquifer consumes the acid, driving up pH and controlling the evolution of the groundwater's major ion chemistry. The thermodynamic energy available to the various functional groups of microbes, except the autotrophic …
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Impacts of Carbonate Mineral Weathering on Hydrochemistry of the Upper Green River Basin, Kentucky
… site is more strongly influenced by carbonate mineral dissolution, reflected in higher specific conductance (SpC) and pH. The SpC at Munfordville ranges from 0.9 to 4.8 times that at Greensburg, averaging 2.0 times higher. Although rainfall is impacted by sulfuric acid from coal burning, river …
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Geochemical Investigations of Mineral Weathering: Quantifying Weathering Intensity, Silicate versus Carbonate Contributions, and Soil-Plant Interactions
This study is the geochemical examination of mineral weathering and its path from hinterland, through sediment deposition and pedogenesis, to its dissolution and eventual uptake into plants or precipitation as carbonate minerals. The three papers examine the rate and character of carbonate and …
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Surfaces of weathered minerals associated with soil drainage: A quantitative microscopic evaluation
… of the surfaces of silt and sand sized soil minerals. These surfaces are a record of the weathering history of the grain in a particular pedochemical environment. The objective of this dissertation was to develop SEM techniques for the qualitative evaluation of weathered mineral surfaces, and …
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Impacts of Climate Change in Snowmelt-Dominated Alpine Catchments: Development and Assessment of Comparative Methods to Quantify the Role of Dynamic Storage and Subsurface Hydrologic Processes
… a pseudoinverse method was developed to compare mineral weathering fluxes in a series of nested sub-catchments over an eleven year study period. Advances from this work include the use of an independently-created energy balance snowmelt model for spatially-distributed hydrologic input for …
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Radium isotopes and radon-222 as tracers of sediment-water interaction in Arctic coastal and lacustrine environments
… organic matter leaching and degradation, and mineral weathering. Radium isotopes (²²³Ra, ²²⁴Ra, ²²⁶Ra, ²²⁸Ra) and radon-222, naturally occurring radioactive isotopes produced in sediments, are well-suited as tracers of nutrients, trace metals, and organic matter cycling processes at the …
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Investigating the impact of microbial interactions with geologic media on geophysical properties
… of organic acids and biosurfactants; (2) mineral weathering promoted by organic acids causes increases in electrolytic conductivity, concomitant with increases in major cation concentrations; (3) interfacial conductivity generally parallels microbial cell concentrations and biofilm …
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Nutritional contribution of atmospheric deposition to the Strandveld vegetation of West Coast South Africa Justine Muhoro Nyaga.
… through which nutrients may be acquired are weathering of rock and atmospheric deposition. Symbiotic and free-living diazotrophic bacteria and blue green algae also contribute N. In ecosystems with limited occurrence of N₂-fixation and occurring on low-nutrient bedrock, atmospheric deposition …
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Nitrate Sorption in the Soils of the Coweeta Hydrologic Laboratory
… C, phosphate and sulfate yet there is enough mineral weathering to provide the mineralogical structures that can support positively charged surfaces.
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Radium isotopes and radon-222 as tracers of sediment-water interaction in Arctic coastal and lacustrine environments
… organic matter leaching and degradation, and mineral weathering. Radium isotopes (223Ra, 224Ra, 226Ra, 228Ra) and radon-222, naturally occurring radioactive isotopes produced in sediments, are well-suited as tracers of nutrients, trace metals, and organic matter cycling processes at the …
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Arsenic dispersion associated with the Barbrook gold mine in the Mpumalanga Province of South Africa
… enhanced As mobility as a result of the sulphide mineral weathering which accompanies gold mining and processing. Sampling of local waters, soils and sediments, as well as the ore and waste rock at Barbrook was undertaken during a week of fieldwork in August 1996. A range of chemical analyses were …
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Seasonal and interannual variability in the hydrology and geochemistry of an outlet glacier of the Greenland Ice Sheet
… the impact of glacial hydrology on subglacial weathering. Analysis of partial and total digestions of the riverine suspended load (SSL) found that trace carbonates within the silicate watershed largely controlled the 87Sr/86Sr ratio in the dissolved load. Experiments and sampling transects …
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Effects of Land-Use History on Soil Macro- and Trace Elements in the Southern Piedmont of North America
… In our second study, samples of the upper 0.6-m mineral soil archived in 1962 and 1997 revealed three cycling patterns: 1) Extractable B and Mn were significantly depleted because tree uptake of B and Mn from mineral-soil greatly outpaced resupplies from atmospheric deposition, mineral …
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Seasonal and interannual variability in the hydrology and geochemistry of an outlet glacier of the Greenland Ice Sheet
… the impact of glacial hydrology on subglacial weathering. Analysis of partial and total digestions of the riverine suspended load (SSL) found that trace carbonates within the silicate watershed largely controlled the 'Sr/'Sr ratio in the dissolved load. Experiments and sampling transects …
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Ultramafic Alteration and the Cooling of Earth and Mars
… via incongruent reactions which form clay minerals, iron oxides, and ultimately release cations to the ocean. Due to their instability, they play an out-sized role in Earth's long-term carbon cycle. My first chapter investigates a hitherto unappreciated mechanism by which ultramafic rocks …
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Catchment Structure Regulates Hydrodynamic Drivers of Chemical Weathering in Shallow Forest Soils
… and soil solution acidity are known to influence weathering rates and soil transformation processes, an integrated understanding of these factors together is still lacking. This dissertation explores the effects of subsurface flow on the mobility and distribution of dissolved organic carbon (DOC) …
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Weathering of sulfide ores in model soils, potentially toxic element release and bioavailability
… if improperly disposed of and managed, waste mineral particles can behave as vectors that disperse PTEs via aeolian and fluvial transport, subsequently contaminating soils and crops used to support human populations. The importance of these particles, as sources and influencers of PTE …
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Macro to Micro Legacies of Landuse at the Calhoun Critical Zone Observatory
… the landscape processes of soil erosion, bedrock weathering, and landcover. In this work, interfluve (hilltop) networks were ordered according to Hortonian methodology at the CCZO in South Carolina with corresponding “hillshed” areas delineated and bounded at the base by valleys and streams. At …