The Pondosa fault zone; a distributed dextral-normal-oblique fault system in northeastern California, USA

The tectonic domains of Basin and Range extension, Cascadia subduction zone contraction, and Walker Lane dextral transtension converge in the Mushroom Rock region of northeastern California, USA. We combined analysis of high-resolution topographic data, bedrock mapping, 40Ar/39Ar geochronology, low-...

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Bibliographic Details
Published in:Geosphere (Boulder, Colo.) Colo.), 2023-02, Vol.19 (1), p.179-205
Main Authors: Thompson Jobe, Jessica, Briggs, Richard, Gold, Ryan, DeLong, Stephen, Hille, Madeline, Delano, Jaime, Johnstone, Samuel A, Pickering, Alexandra, Phillips, Rachel, Calvert, Andrew T
Format: Article
Language:English
Subjects:
absolute age
Ar/Ar
Basin and Range Province
C-14
California
carbon
Cascadia subduction zone
Cenozoic
deformation
digital elevation models
extension tectonics
fault scarps
fault zones
faults
geodesy
isotopes
laser methods
lateral faults
lidar methods
microplates
normal faults
North America
northeastern California
oblique-slip faults
plate boundaries
plate tectonics
Pondosa fault zone
radioactive isotopes
Red Mountain
remote sensing
right-lateral faults
stratigraphic units
Structural geology
tectonics
thermochronology
tomography
United States
upper Cenozoic
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Summary:The tectonic domains of Basin and Range extension, Cascadia subduction zone contraction, and Walker Lane dextral transtension converge in the Mushroom Rock region of northeastern California, USA. We combined analysis of high-resolution topographic data, bedrock mapping, 40Ar/39Ar geochronology, low-temperature thermochronology, and existing geologic and fault mapping to characterize an extensive dextral-normal-oblique fault system called the Pondosa fault zone. This fault zone extends north-northwest from the Pit River east of Soldier Mountain, California, into moderately high-relief volcanic topography as far north as the Bartle (California) townsite with normal and dextral offset apparent in geomorphology and fault exposures. New and existing 40Ar/39Ar and radiocarbon dating of offset lava flows provides ages of 12.4 ka to 9.6 Ma for late Cenozoic stratigraphic units. Scarp morphology and geomorphic expression indicate that the fault system was active in the late Pleistocene. The Pondosa fault zone may represent a dextral-oblique accommodation zone between north-south-oriented Basin and Range extensional fault systems and/or part of the Sierra Nevada-Oregon Coast block microplate boundary.
ISSN:1553-040X
1553-040X
DOI:10.1130/GES02450.1