Dissertation/Thesis Abstract

Quantifying Late Quaternary Deformation In The Santa Ynez Valley, Santa Barbara County, California
by Farris, Andrew C., M.S., California State University, Long Beach, 2017, 158; 10262235
Abstract (Summary)

The Santa Maria Basin (SMB) is located on the Central Coast of California and comprises the area bound by the Santa Ynez Fault to the south, the Little Pine-Foxen Canyon-Santa Maria River Fault Zone to the northeast, and the Hosgri fault to the west. The SMB is located in a zone of convergence between the clockwise rotating Western Transverse Ranges (WTR) and the relatively non-rotated Southern Coast Ranges (SCR). The rate and style of Late Quaternary deformation and uplift has been poorly defined in the SMB. The Zaca Creek Field Area, in the northern Santa Ynez Valley, contains a sequence of fluvial strath terraces that provide markers for uplift and deformation. Fluvial terraces along Zaca Creek were mapped as 8 separate units, surveyed for deformation with GPS and 1 m Pleiades DEM based transects, and sampled for Luminescence dating. Luminescence results suggest an age of 48 ka for a terrace 52 m above the active channel, and an age of 79 ka for a terrace 75 m above the active channel. One fold and two faults have been active in the Late Quaternary, but the structures slip or deform at very slow rates of 0.05 m/ka-0.17 m/ka. Stream incision rates and minimum rock uplift rates range between 0.95 m/ka to 1.08 m/ka. The rapid uplift rates of the Santa Ynez Valley are best explained by continued vertical axis rotation of the WTR, where strain is distributed via a regional detachment.

Indexing (document details)
Advisor: Onderdonk, Nate W.
Commitee: Garcia, Antonio F., Kelty, Tom K.
School: California State University, Long Beach
Department: Geological Sciences
School Location: United States -- California
Source: MAI 56/03M(E), Masters Abstracts International
Subjects: Geology
Keywords: California, Santa Maria Basin
Publication Number: 10262235
ISBN: 978-1-369-69848-0
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