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Filtering by: Creator Niemi, Nathan A. Remove constraint Creator: Niemi, Nathan A. Creator Townsend, Kirk F. Remove constraint Creator: Townsend, Kirk F. Keyword Western Transverse Ranges Remove constraint Keyword: Western Transverse Ranges Discipline Science Remove constraint Discipline: Science

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  • Reverse faulting within a continental plate boundary transform system [Data set]

    work
    Creator:
    Townsend, Kirk F., Clark, Marin K., and Niemi, Nathan A.
    Description:
    These datasets support the findings of Townsend et al. (in review) investigating the timing of faulting relative to changes in the orientation of the North American-Pacific plate boundary. Coeval with development of an oblique plate boundary segment (i.e. the “Big Bend” of the San Andreas fault), active shortening is inferred to have initiated at ~5 Ma in the Western Transverse Ranges (WTR). However, new low-temperature thermochronometric transects yield Miocene to Pleistocene apatite (U-Th-Sm)/He cooling ages and partially reset zircon (U-Th)/He ages. Inverse thermal modelling indicate that reverse faulting initiated as early as 10 Ma, several million years prior to our current understanding of the timing of the Big Bend. New and existing thermochronometry data delineate the WTR as the locus of rapid post-Miocene exhumation, and demonstrate that similar exhumation is not present in the broader region surrounding the Big Bend. We posit that reverse faulting is localized in the WTR because of a weak underlying lithosphere and predates the more recent geometric anomaly of the restraining bend in the transform margin.
    Keyword:
    Reverse faults, Fault initiation, Fault propagation, Low-temperature thermochronometry, Western Transverse Ranges, and San Andreas Fault
    Citation to related publication:
    Townsend, K. F., Clark, M. K., & Niemi, N. A., in review, Reverse faulting within a continental plate boundary transform system. Tectonics
    Discipline:
    Science