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Full-Text Articles in Physical Sciences and Mathematics
The Geochemistry Of Loess: Asian And North American Deposits Compared, Daniel R. Muhs
The Geochemistry Of Loess: Asian And North American Deposits Compared, Daniel R. Muhs
United States Geological Survey: Staff Publications
Loess is widely distributed over Asia and North America and constitutes one of the most important surficial deposits that serve as terrestrial records of the Quaternary. The oldest Pleistocene loess in China is likely ∼2.6 Ma, thus spanning much or all of the Pleistocene. In North America, most loess is no older than the penultimate glacial period, with the exception of Alaska, where the record may go back to ∼3.0 Ma. On both continents, loess deposits date primarily to glacial periods, and interglacial or interstadial periods are represented by paleosols. Both glacial and non-glacial sources of silts that comprise the …
Using Strontium Isotopes In Conjunction With Major, And Trace Elements To Identify Water/Rock Interaction In The Upper Kittitas County, Washington, James Patterson, Carey Gazis
Using Strontium Isotopes In Conjunction With Major, And Trace Elements To Identify Water/Rock Interaction In The Upper Kittitas County, Washington, James Patterson, Carey Gazis
All Master's Theses
The complex bedrock lithologies in the Upper Kittitas County provide an ideal setting for developing isotopic methodology to identify groundwater sources and track flow paths through water-rock interaction. A wide range of 87Sr/86Sr (0.7040 to 0.7068) in surface waters, springs, and groundwater from wells was found, allowing for identification of the individual signatures of lithologic units. Rock leachates from different lithology were compared to water samples to determine a general 87Sr/86Sr signature of the water-rock interaction for that lithology. The signatures identified were systematically lower than their associated waters, but similar enough to identify the expected 87Sr/86Sr of water-rock interaction …
Removal Of Select Chlorinated Hydrocarbons By Nanoscale Zero-Valent Iron Supported On Powdered Activated Charcoal, Md Abu Raihan Chowdhury
Removal Of Select Chlorinated Hydrocarbons By Nanoscale Zero-Valent Iron Supported On Powdered Activated Charcoal, Md Abu Raihan Chowdhury
Browse all Theses and Dissertations
Nanoscale Zero Valent Iron (NZVI) has shown limited effectiveness in degrading chlorinated hydrocarbons (CHCs), like 1,1,1-Trichloroethane (1,1,1-TCA) and Trichloroethene (TCE), in aqueous solution. A rapid agglomeration behavior of NZVI particles due to van der waals and magnetic forces can negatively impact its overall effectiveness due to increase in particle size, and decline in CHC degradation kinetics. Different support materials, such as clays and activated carbon, have been used to stabilize NZVI particle and reduce agglomeration in aqueous solution. In this bench-scale study, NZVI supported on Powdered Activated Charcoal (PAC) was selected to prepare a composite, called PAC/NZVI, for a more …
Cycling Of Gypsiferous White Sands Aerosols In The Shallow Critical Zone At White Mountain, New Mexico, Patrick Richard Rea
Cycling Of Gypsiferous White Sands Aerosols In The Shallow Critical Zone At White Mountain, New Mexico, Patrick Richard Rea
Open Access Theses & Dissertations
Dry deposition significantly affects evolution of the critical zone by nutrient supply and contributing to soil genesis. Dust influx and cycling in soils are difficult to quantify because dust sources can be chemically similar to local soils. White Sands, New Mexico, emits gypsum dust with a unique chemical and isotopic signature, providing an opportunity to investigate dust deposition and its movement in soils. This study evaluated the mobility of White Sands dust particles in the critical zone at White Mountain, New Mexico, a highland 100 km downwind. Four soil profiles were collected over limestone, igneous, mixed limestone and dolostone, and …