THE TECTONIC GEOMORPHOLOGY OF THE SANTA YNEZ MOUNTAINS, TRANSVERSE RANGES, CALIFORNIA

For over a century, scientists have been investigating how landscapes are shaped by interactions between tectonic uplift, geomorphic processes, lithology, and climate. The Santa Ynez Mountains of the Transverse Ranges, CA host a previously documented uplift gradient and varied lithology, but a relatively constant climate across the range. This makes a great study area to investigate how changes in uplift rate and lithologic heterogeneity affect landscape form. Our preliminary topographic analyses show an increase in normalized channel steepness from west to east across the range, which could be due to a gradient in erosion rates and/or differences in lithology as previously suggested by Duvall et al (2004). We also observe a strong chi gradient across the crest of the Santa Ynez Mountains, indicating that the main divide is migrating to the north. This study is still in progress, and we plan to compile existing and take new rock strength measurements using a Schmidt hammer and collect samples for basin averaged erosion rates (using Beryllium-10 in quartz) to better document the erosion rate gradient and how lithologic variation is influencing topographic metrics.