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Full-Text Articles in Physical Sciences and Mathematics
Environmental Influences On The Mobility And Speciation Of Arsenic In The Geothermal Waters Of El Tatio Geyser Field, Chile, Lindsey R. Johnson
Environmental Influences On The Mobility And Speciation Of Arsenic In The Geothermal Waters Of El Tatio Geyser Field, Chile, Lindsey R. Johnson
LSU Master's Theses
El Tatio geyser field, northern Chile, impacts regional water quality, policy, and agricultural commerce due to the geothermal waters containing high concentrations of naturally-occurring arsenic (As). In the circumneutral pH, non-sulfidic thermal waters at El Tatio, dissolved arsenite [As(III)] dominates geyser discharge water upstream, but dissolved arsenate [As(V)] dominates downstream. Microbial mats and sediments were analyzed for changes in As speciation using X-ray spectroscopy methods, such as XANES and EXAFS at both the As and Fe K-edges, combined with ATR-FTIR spectroscopy and molecular genetics, to understand As cycling. The sediments and microbial mats were dominated by As(V) speciated as both …
Mineralogy And Micromorphology Of An Atacama Desert Soil, Chile: A Model For Hyperarid Pedogenesis, Michael S. Howell
Mineralogy And Micromorphology Of An Atacama Desert Soil, Chile: A Model For Hyperarid Pedogenesis, Michael S. Howell
UNLV Theses, Dissertations, Professional Papers, and Capstones
The Atacama Desert is the oldest and driest desert on Earth. Hyperarid soils in this desert are dominated by rare (or exclusive) salt minerals and assemblages. Previous research details salt origins and abundance, however pedogenic processes involved in salt distribution are not adequately explained. Therefore, the main goal of this investigation was to identify and document evidence for hyperarid pedogenesis (via salt mineralogy and soil micromorphology) at a field site, Oficina Ercilla, located ~80 km northeast of Antofagasta, Chile within the Central Depression and hyperarid core of the Atacama Desert. This study presents an interpretational model for hyperarid pedogenesis, which …