Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemishy inlo a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between weathering index and depth. In this ...

Title of Document: TRACING CONTINENTALWEATHERING USING LITHIUM AND MAGNESIUM ISOTOPES: INSIGHTS FROM THE CHEMICAL WEATHERING OF COLUMBIA RIVER BASALTS AND MASS BALANCE MODELING Xiao-Ming Liu, Ph.D., 2013 Directed By: Professors Roberta L. Rudnick & William F. McDonough, Department of Geology Chemical weathering is an important mechanism that changes the mass and composition of the continental c...

Tectonic uplift is one of the key factors controlling the supply of material to weathering environments. At present however, there is debate about whether tectonics or climate plays a larger role in controlling chemical weathering rates on a global scale over geologic time. We measured riverine weathering fluxes from twelve catchments along the Skykomish River in the Washington Cascades, where ...

Landscapes evolve in response to external forces, such as tectonics and climate, that influence surface processes of erosion and weathering. Internal feedbacks between erosion and weathering also play an integral role in regulating the landscapes response. Our understanding of these internal and external feedbacks is limited to a handful of field-based studies, only a few of which have explicit...

Weathering is a continuous process; the best way to deal with weathered coal is to identify the extent of weathering. Based on level of weathering its consumption pattern should be changed, this will help in minimizing the effect of weathering on coke quality. Due to weathering, various technological properties of coal get altered such as as ash, free swelling index, fluidity, plastic range and...

Weathering of silicate minerals impacts many geological and ecological processes. For example, the weathering of basalt contributes significantly to consumption of atmospheric carbon dioxide (CO2) and must be included in global calculations of such consumption over geological timeframes. Here we compare weathering advance rates for basalt (wD β ), where D and β indicate the scale at which the r...

Connections between glaciation, chemical weathering, and the global carbon cycle could steer the evolution of global climate over geologic time, but even the directionality of feedbacks in this system remain to be resolved. Here, we assemble a compilation of hydrochemical data from glacierized catchments, use this data to evaluate the dominant chemical reactions associated with glacial weatheri...

The relationships among climate, physical erosion, and chemical weathering have remained uncertain, because long-term chemical weathering rates have been difficult to measure. Here we show that long-term chemical weathering rates can be measured by combining physical erosion rates, inferred from cosmogenic nuclides, with dissolution losses, inferred from the rock-to-soil enrichment of insoluble...

During the 2010 Deepwater Horizon oil well blowout in the Northern Gulf of Mexico (GoM), the application of 6.97 million litres of chemical dispersants was used at the well-head and on the sea surface to promote oil degradation and weathering of the Mississippi Canyon 252 (MC252) crude oil. Chemical dispersants encourage microbial degradation by increasing the surface area of the spilled oil, w...

Quantifying long-term rates of chemical weathering and physical erosion is important for understanding the long-term evolution of soils, landscapes, and Earth’s climate. Here we describe how long-term chemical weathering rates can be measured for actively eroding landscapes using cosmogenic nuclides together with a geochemical mass balance of weathered soil and parent rock. We tested this appro...