The effect of watershed spatial scale on chemical weathering is inadequately known for subtropical environments. In order to determine the relationship between watershed scale and weathering chemistry, the Enoree River basin was sampled at seven different spatial scales ranging from second-order watersheds smaller than 2 km^2 to a sixth order watershed of 1840 km^2. The second-order watersheds ...

[1] In the McMurdo Dry Valleys, Antarctica, dilute glacial meltwater flows down wellestablished streambeds to closed basin lakes during the austral summer. During the 6–12 week flow season, a hyporheic zone develops in the saturated sediment adjacent to the streams. Longer Dry Valley streams have higher concentrations of major ions than shorter streams. The longitudinal increases in Si and K su...

[1] Spectral interpretation that silicic rocks are widespread on Mars implies that Earth’s differentiated crust is not unique. Evaluation of observations bearing on the composition of the Martian crust (Martian meteorite petrology and a possible crustal assimilant, analysis of Mars Pathfinder rocks, composition of Martian fines, interpretation of spacecraft thermal emission spectra, and inferre...

cerium oxide (ceria) nano particle, as photodegradation prevention agent was studied in water-based polyurethane clear coat  systems. polyurethane coatings show superior weathering resistance compared with acrylic melamine systems. however, any chemical change has detrimental effects on the property profile of pu coatings. coatings containing various amounts of cerium oxide nanoparticles were p...

The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial p...

Oxidation–hydration weathering of uraninite, the most common U-bearing mineral in nature, comprises various physical and chemical processes that lead to the destruction of the fluorite-type structure of uraninite where U is present as tetravalent. This results in replacement of uraninite by weathering products containing U in hexavalent form, i.e. as uranyl ion, UO2 2+. The final assemblage of ...

The Great Oxidation Event (GOE) is currently viewed as a protracted process during which atmospheric oxygen increased above ∼10(-5) times the present atmospheric level (PAL). This threshold represents an estimated upper limit for sulfur isotope mass-independent fractionation (S-MIF), an Archean signature of atmospheric anoxia that begins to disappear from the rock record at 2.45 Ga. However, an...