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Showing 1 to 20 of 28 for “"Weathering Rates"”.
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Hillslope erosion and weathering rates in Earth's most rapidly uplifting mountains
Knowledge of hillslope erosion rates and processes is necessary for understanding landscape response to tectonic and climatic forcing and for determining the degree to which mountains regulate biogeochemical cycles and global climate. Landslide erosion and soil production are the principle …
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Stable isotope and trace element fractionation and implications for chemical weathering rates
The student, Nicole Fernandez-Franzan, accepted the attached license on 2020-05-05 at 04:05.
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Using high resolution Sr isotope data from the Nama Group, South Africa, to constrain global stratigraphic relationships and continental weathering rates in the terminal Ediacaran
… and/or environmental change. Continental weathering fluxes into the oceans can influence redox conditions and seawater chemistry and can be tracked using the strontium isotope ratio of seawater, which can be faithfully captured by carbonate minerals. However, analysis of strontium isotopes …
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A method for correlation of gravestone weathering and air quality (SO2), West Midlands, UK
… cores, lake acidification studies and gravestone weathering have all been used to reconstruct the history of air quality. A 120-year record of acid deposition reconstructed from lead-lettered marble gravestone weathering combined with SO2 measurements from the air monitoring network across the …
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Weathering below Irish blanket bogs and impacts on carbon dynamics
… investigates CO2 consumption by chemical weathering related to mineral soils and bedrock underlying peatland catchments in Ireland via measurement of major ion fluxes and runoff. Influence of peatland condition and substrate composition is investigated by comparison of catchments with …
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Adsorption–Desorption Reactions in the Weathering Zone: Implications for Silicate Weathering & the Carbon Cycle
The carbonic acid-driven chemical weathering of silicate minerals removes carbon dioxide (CO2) from Earth's atmosphere. The tectonic processes of uplift, exhumation, and erosion modulate the negative feedback relationship between climate, silicate weathering rates, and atmospheric CO2 removal rates …
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Weathering Pathways and Limitations in Biogeochemical Models: Application to Earth System Evolution
… due to long-term geological limitation of global weathering rates. The timescale matches the observed gaps between extreme glaciations at this time, suggesting that the late Neoproterozoic system was oscillating around a steady state temperature below the snowball threshold. In the model, the …
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Inferences on the influences of age & porosity on oxidative weathering of seafloor massive sulfide deposits at the endeavour segment of the Juan de Fuca Ridge
… are collectively described as oxidative weathering. While the observed textures of these deposits suggest significant variation in weathering rates, neither the causes of this variation nor the drivers that govern biogeochemical oxidation of massive sulfides are well-characterized. To …
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Basalt alteration and its consequences
… modelling coupled to geochemical analyses. The weathering of basalt creates unique chemical environments that can drive carbonate mineral precipitation and other secondary mineral formation. The extreme reactivity of basalt, with very fast weathering rates relative to other surface rocks, means …
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Inferences on the Influences of Age & Porosity on Oxidative Weathering of Massive Sulfides at the Endeavour Segment of Juan de Fuca Ridge
… are collectively described as oxidative weathering. While the observed textures of these deposits suggest significant variation in weathering rates, neither the causes of this variation nor the drivers that govern biogeochemical oxidation of massive sulfides are well-characterized. To …
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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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Evolution of chemical composition along river drainage networks
… in the underlying bedrock. Other indices of weathering rates and processes showed strong similarities despite the change in bedrock. The dominance of silica, alkalinity, calcium and sodium (after sea-salt correction) in surface waters suggests that anorthite and albite are the dominant …
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Mechanisms of nutrient limitation and nutrient acquisition in managed and unmanaged forest ecosystems
… earth elements to serve as tracers of apatite weathering by mycorrhizal fungi in soils. In the greenhouse experiment, both of these tracers showed clear effects of biological systems (mycorrhizal and non-mycorrhizal birch seedlings) on the weathering rates of trace minerals including apatite. …
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Biogeochemical Cycling and Paleoenvironmental Reconstructions of the Toarcian Oceanic Anoxic Event from Western North America
… of the osmium cycle suggests that continental weathering rates increased during the T-OAE by 230 – 540%. Rhenium abundance data also suggests that the increased geographic extent of marine anoxia during the T-OAE caused a global drawdown in the seawater rhenium inventory. Iron speciation data …
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Physical Investigation of Field Scale Groundwater Recharge Processes in the Virginia Blue Ridge Physiographic Province
… in Floyd County, Virginia indicate that recharge rates to the subsurface are controlled by a small scale thrust fault associated with regional thrust faulting within the Blue Ridge Province. Recharge rates appear to be correlated to spatial variation in the hydraulic conductivity of the regolith, …
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Role of fluids in geological processes
… environment where generation of abiotic carbohydrates occur. The ocean chemistry varied in the geologic past to reflect major changes in the intensity of weathering, rates of midocean ridge hydrothermal discharge, changes in the climate and atmospheric CO2 concentration, and also played an …
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Quantifying the impacts of exogenous dust inputs to watersheds using reactive transport modeling
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms
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RE – OS AND PGE GEOCHEMISTRY OF ORGANIC-RICH SEDIMENTARY ROCKS AND PETROLEUM
… identify oil source units. Chapter three demonstrates, through the analysis of Kimmeridge Clay Fm. core and North Sea oil, that unradiogenic mantle like values within oils from wells in the Viking Graben and East Shetland Basin cannot be inherited from source. It is hypothesised that they are …
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Microbial and Chemical Zonation and Mineral Weathering in the Middendorf Aquifer, South Carolina
… to better understand the kinetics of chemical weathering in the Cretaceous Middendorf aquifer of South Carolina, USA, and the relationship of this process to subsurface microbial activity. The model accounts for the kinetics of mineral dissolution and precipitation, ion exchange, and the CO2 …
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Silicate weathering in the Himalayas: Constraints from the Li isotopic composition of river systems
Chemical weathering of silicate rock consumes atmospheric CO2 and supplies the oceans with cations, thereby controlling both seawater chemistry and climate. The rate of CO2 consumption is closely linked to the rate of CO2 outgassing from the planetary interior, providing a negative feedback loop …
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