Constraints on rock uplift in the eastern Transverse Ranges and northern Peninsular Ranges and implications for kinematics of the San Andreas fault in the Coachella Valley, California, USA

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dc.contributor.authorSpotila, James A.en
dc.contributor.authorMason, Cody C.en
dc.contributor.authorValentino, Joshua D.en
dc.contributor.authorCochran, William J.en
dc.contributor.departmentGeosciencesen
dc.date.accessioned2020-08-10T17:59:24Zen
dc.date.available2020-08-10T17:59:24Zen
dc.date.issued2020-06en
dc.description.abstractThe nexus of plate-boundary deformation at the northern end of the Coachella Valley in southern California (USA) is complex on multiple levels, including rupture dynamics, slip transfer, and three-dimensional strain partitioning on nonvertical faults (including the San Andreas fault). We quantify uplift of mountain blocks in this region using geomorphology and low-temperature thermochronometry to constrain the role of long-term vertical deformation in this tectonic system. New apatite (U-Th)/He (AHe) ages confirm that the rugged San Jacinto Mountains (SJM) do not exhibit a record of rapid Neogene exhumation. In contrast, in the Little San Bernardino Mountains (LSBM), rapid exhumation over the past 5 m.y. is apparent beneath a tilted AHe partial retention zone, based on new and previously published data. Both ranges tilt away from the Coachella Valley and have experienced minimal denudation from their upper surface, based on preservation of weathered granitic erosion surfaces. We interpret rapid exhumation at 5 Ma and the gentle tilt of the erosion surface and AHe isochrons in the LSBM to have resulted from rift shoulder uplift associated with extension prior to onset of transpression in the Coachella Valley. We hypothesize that the SJM have experienced similar rift shoulder uplift, but an additional mechanism must be called upon to explain the pinnacle-like form, rugged escarpment, and topographic disequilibrium of the northernmost SJM massif. We propose that this form stems from erosional resistance of the Peninsular Ranges batholith relative to more-erodible foliated metamorphic rocks that wrap around it. Our interpretations suggest that neither the LSBM nor SJM have been significantly uplifted under the present transpressive configuration of the San Andreas fault system, but instead represent relict highs due to previous tectonic and erosional forcing.en
dc.description.notesSupport for this study was provided by U.S. National Science Foundation (Tectonics Program) grants EAR-1145115 and EAR-1802026. Careful reviews from Julie Fosdick and Victoria Langenheim significantly improved the scientific content and style of this manuscript. The authors thank Rebecca Dorsey for scientific leadership and insight on this project, and Luke Sabala at Joshua Tree National Park for his prior work and sharing analytical data and insights from his M.S. thesis under the guidance of Phil Armstrong. Doug Yule and Michelle Cooke are thanked for organizing this special volume on San Gorgonio Pass.en
dc.description.sponsorshipU.S. National Science Foundation (Tectonics Program) [EAR-1145115, EAR-1802026]en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1130/GES02160.1en
dc.identifier.issn1553-040Xen
dc.identifier.issue3en
dc.identifier.urihttp://hdl.handle.net/10919/99635en
dc.identifier.volume16en
dc.language.isoenen
dc.rightsCreative Commons Attribution-NonCommercial 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/en
dc.titleConstraints on rock uplift in the eastern Transverse Ranges and northern Peninsular Ranges and implications for kinematics of the San Andreas fault in the Coachella Valley, California, USAen
dc.title.serialGeosphereen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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