Tectonically-dominated Quaternary landscape evolution of the Ventura basin, southern California, quantified using cosmogenic isotopes and topographic analyses

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dc.contributor.authorRood, DHen_AU
dc.contributor.authorHughes, Aen_AU
dc.contributor.authorWhittaker, ACen_AU
dc.contributor.authorBell, REen_AU
dc.contributor.authorWilcken, KMen_AU
dc.contributor.authorCorbett, Aen_AU
dc.contributor.authorBierman, Pen_AU
dc.contributor.authorDeVecchio, DEen_AU
dc.contributor.authorRockwell, TKen_AU
dc.date.accessioned2024-05-08T00:28:32Zen_AU
dc.date.available2024-05-08T00:28:32Zen_AU
dc.date.issued2020-05-04en_AU
dc.date.statistics2023-05-08en_AU
dc.description.abstractSpatial and temporal variations in fault activity informs models of seismic hazards and can affect local patterns of relief generation and channel morphology. Therefore, the quantification of rates of fault activity has important applications for understanding natural hazards and landscape evolution. Here, we quantify the complex interplay among tectonic uplift, topographic development, and channel erosion recorded in the hanging walls of several seismically-active reverse faults in the Ventura basin, southern California, USA. We use cosmogenic 26Al/10Be isochron burial dating to construct a basin-wide geochronology for the Saugus Formation: an important, but poorly dated, regional Quaternary strain marker. Our geochronology of the Saugus Formation is used to calculate tectonically-driven rock uplift rates and reduce uncertainties in fault-slip rates. In addition, we calculate 10Be catchment-averaged erosion rates, characterise patterns of catchment relief and channel steepness indices, and analyse river long-profiles in fault hanging walls to compare with patterns of fault displacement rates averaged over various temporal scales. The results of the burial dating confirm that the Saugus Formation is time-transgressive with ages for the top of the exposed Saugus Formation of ~0.4 Ma in the western Ventura basin and ~2.5 Ma in the eastern Ventura basin. The burial ages for the base of shallow marine sands, which underlie the Saugus Formation throughout the basin, are ~0.6 Ma in the western Ventura basin and ~3.3 Ma in the eastern Ventura basin. The results of the landscape analysis indicate that relief, channel steepness, and erosion rates are still adjusting to tectonic boundary conditions imposed by different tectonic perturbations that have occurred at various times since ~1.5 Ma, which include fault initiation and fault linkage. The data presented here suggest that, for transient landscapes in sedimentary basins up to 2500 km2, where climate can be considered uniform, fault activity is the primary control on patterns of relief generation and channel morphology over periods of 104 to 106 years. © Author(s) 2022. This work is distributed under the Creative Commons Attribution 4.0 Licence.en_AU
dc.identifier.citationRood, D., Hughes, A., Whittaker, A., Bell, R., Wilcken, K., Corbett, A., Bierman, P., DeVecchio, D., & Rockwell, T. (2020). Tectonically-dominated Quaternary landscape evolution of the Ventura basin, southern California, quantified using cosmogenic isotopes and topographic analyses. Presentation to the EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-16537. Retrieved from: https://doi.org/10.5194/egusphere-egu2020-16537en_AU
dc.identifier.conferenceenddate2020-05-08en_AU
dc.identifier.conferencenameEGU General Assembly 2020en_AU
dc.identifier.conferenceplaceOnlineen_AU
dc.identifier.conferencestartdate2020-05-04en_AU
dc.identifier.otherEGU2020-16537en_AU
dc.identifier.urihttps://doi.org/10.5194/egusphere-egu2020-16537en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15588en_AU
dc.language.isoenen_AU
dc.publisherCopernicus GmbHen_AU
dc.relation.urihttps://doi.org/10.5194/egusphere-egu2020-16537en_AU
dc.subjectTectonicsen_AU
dc.subjectQuaternary perioden_AU
dc.subjectCaliforniaen_AU
dc.subjectGeologic faultsen_AU
dc.subjectGeomorphologyen_AU
dc.subjectExceptional natural disastersen_AU
dc.subjectBeryllium 10en_AU
dc.subjectErosionen_AU
dc.titleTectonically-dominated Quaternary landscape evolution of the Ventura basin, southern California, quantified using cosmogenic isotopes and topographic analysesen_AU
dc.typeConference Abstracten_AU
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