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Date Permissions Signed


Date of Award


Document Type

Masters Thesis

Degree Name

Master of Science (MS)



First Advisor

Housen, Bernard Arthur

Second Advisor

Burmester, Russell F.

Third Advisor

Caplan-Auerbach, Jacqueline


The Fish Creek-Vallecito basin (FCVB) is a large Plio-Pleistocene sedimentary basin in the western Salton Trough, CA. The FCVB formed during subsidence along the West Salton Detachment fault and was uplifted and tilted when slip along the West Salton Detachment fault ended and the region became dominated by strike-slip faulting. This study uses paleomagnetism and magnetostratigraphy to determine the timing and rate of rotation of the FCVB. Two hundred and one sites were sampled in the Palm Spring Group of the FCVB. Magnetite and hematite are identified as carriers of remanence, and rock magnetic measurements are consistent with a magnetite detrital remanent magnetization and hematite detrital remanent magnetization or chemical remanent magnetization. Polarity interpretation yielded nine geomagnetic polarity intervals. Correlation of the magnetostratigraphy to the geomagnetic polarity time scale at a U-Pb dated ash layer within the sampled section yields an age span of 1.78 to 3.33 Ma for the section. Comparison of the modern expected direction with mean normal and reverse-polarity directions yields 14±3° to 17±3° of clockwise rotation for the FCVB. Rotations are interpreted to be uniform for the sampled section and younger than the approximately 1.2 Ma age attributed to uplift and deformation of the FCVB. Rotation of the FCVB is attributed to slip along the Elsinore fault. Calculations of fault slip from 14±3° or 17±3° of clockwise rotation of the FCVB since 1.2 Ma produce maximum estimates of 2.1±0.3 or 2.4±0.3 mm/yr of right lateral slip along the Elsinore fault and vertical-axis rotation rates of 16±3° or 19±3° /Myr of clockwise rotation.





Western Washington University

OCLC Number


Subject – LCSH

Faults (Geology)--California--Fish Creek Basin; Faults (Geology)--California--Vallecito Basin; Strike-slip faults (Geology)--California--Fish Creek Basin; Strike-slip faults (Geology)--California--Vallecito Basin; Paleomagnetism--California--Fish Creek Basin; Paleomagnetism--California--Vallecito Basin; Geology, Stratigraphic--Pliocene; Geology, Stratigraphic--Pleistocene

Geographic Coverage

Fish Creek Basin (Calif.); Vallecito Basin (Calif.)




masters theses




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