Geology Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2774

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    Topographic signatures in the Himalaya: A geospatial survey of the interaction between tectonics and erosion in the Modi Khola valley, central Nepal
    (2009) Walsh, Lisa Schleicher; Martin, Aaron J; Geology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Spurred by the recognition that lithologic resistivity to erosion influences the steepness of terrain, the purpose of this study is to enhance our understanding of feedbacks between erosion and tectonics in the Himalaya. Using spatial statistics, within a Geographic Information Systems (GIS) framework, this study extracts steepness and curvature values from the terrain to identify the unique spatial signature of lithologic units in the Annapurna Range. The spatial relationship of faults and significant changes in river steepness (ksn) and concavity (θ) are examined in this project using high resolution digital elevation models (DEMs), derived from a variety of interpolation methods. Through these quantifications, I explore the possibility of a new model for tectonic activity in central Nepal, in an effort to improve our understanding of how surface processes sculpt the landscape.
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    Characterization of the spatial differences in hydrological functioning in a tidal marsh, Patuxent River, MD: A framework for understanding nutrient dynamics
    (2004-12-08) Phemister, Karen; Prestegaard, Karen L.; Geology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study investigates spatial variations in sediment hydraulic conductivity (K), network channel shape and horizontal groundwater flux magnitude toward tidal network channels in a freshwater tidal marsh. Results showed the average value of K at zero meters from the creekbank was significantly higher than the K at both 5 and 15 meters from the network channel creekbank. Creekbank gradient did increase with increasing distance from the main channel and some data indicated that channel width-to-depth ratio (F), which is inversely related to creekbank gradient, correlates well with K. In addition, horizontal groundwater flux magnitude at a depth of 11 cm was significantly greater than flux magnitude at 22 cm below the ground surface at the first-order network channel location. Horizontal flux magnitude was also significantly higher from 5 to 0 meters than from 15 to 5 meters from the network channel creekbank at both the first- and second-order channel locations.