Publication Date
Summer 2022
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Geology
Advisor
Kimberly Blisniuk
Subject Areas
Geology
Abstract
New Quaternary geologic slip rates were determined for the northern Rodgers CreekFault at two sites near Windsor, CA. Slip rates were determined through Quaternary mapping and geochronologic dating, specifically in situ cosmogenic 10Be, and infrared stimulated luminescence dating. At the Shiloh Ranch Regional Park site, a terrace dated to ~3.2 ka – 7.9 ka and offset 18 m – 45 m yielded a preliminary slip rate of 6.1 mm/yr ± 4.5 mm/yr. At the Foothill Regional Park site, an older Quaternary terrace and a younger alluvial fan deposit are reconstructed with source drainages across the fault. Reconstructing the ~68.8 ka – 88.8 ka terrace with a similar terrace across the fault produced an offset of 280 m – 400 m. Reconstructing the ~24.2 ka – 35.7 ka alluvial fan with a source drainage across the fault, produced an offset of 85 m – 130 m. This reconstruction also realigns six pairs of deposits with similar relative geomorphic age across the fault, immediately to the south. These results were used to calculate slip rates of 4.3 mm/yr ± 1.1 mm/yr since ~88 ka and 3.6 mm/yr ± 1.2 mm/yr since ~35 ka, respectively, and a combined slip rate of 4.2 mm/yr ± 1.0 mm/yr. Comparison of these slip rates with published slip rates allows for a greater understanding of slip partitioning within the Santa Rosa Pull-Apart basin and within the North Coast section of the San Andreas Fault system.
Recommended Citation
Walker, Alianora, "Quaternary Geologic Slip Rates for the Northern Rodgers Creek Fault, Near Windsor, Ca" (2022). Master's Theses. 5324.
DOI: https://doi.org/10.31979/etd.yc5r-nuzd
https://scholarworks.sjsu.edu/etd_theses/5324
