Master of Science (MS)
Emmanuel J. Gabet
Geomorphometry, Glacial geomorphology, Sierra Nevada
Geomorphology; Geology; Geographic information science and geodesy
This study employed a semi-automated approach to evaluate the degree of glacial modification of bedrock valleys in the Sierra Nevada, California, by quantifying morphological variability in cross-sectional form assessed from ~27,000 locations throughout the range. Measures of morphology including a shape ratio, a quadratic curve fit, and a power law curve fit were computed for each cross-section along with a novel metric, the V–index, and were compared to mapped glacial extent and bedrock lithology. Results indicate that Quaternary glaciations had a significant effect on bedrock valley morphology that is locally variable and largely independent of lithology at the range scale. Analysis of valley cross-sections and longitudinal profiles further suggest that glaciers in the Sierra Nevada modified pre-existing fluvial valleys primarily through widening. Moreover, the novel V-index is proposed as an alternative to traditional morphological measures due to its utility in describing irregular valley cross-sections and equivalent discriminatory power compared to established techniques for quantifying glacial geomorphology.
Zimmer, Paul D., "Assessing Glacial Modification of Bedrock Valleys in the Sierra Nevada, California, Using a Novel Approach" (2016). Master's Theses. 4784.