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Paleomagnetically defined brief lifespans for two large shield volcanoes in the Cascades Arc

January 9, 2023

Mafic to intermediate shield volcanoes with multi-cubic-kilometer eruptive volumes are common in the Cascades Volcanic Arc, but little is known about their eruptive histories as either singular or sustained episodes, or the total time required for their construction. Paleomagnetic data were collected from the lava flows of Ash Creek Butte (17 sites) and Crater Mountain (14 sites) in northern California; both volcanoes are large shields with total volumes of ∼11 km3 each. Tightly clustered paleomagnetic results at both volcanoes, when coupled with analysis of geomagnetic secular variation, suggest that each edifice was built in only a few centuries, possibly in as little time as 50–90 years, indicating sub-century to century scale eruptive durations for two sizeable regional shield volcanoes within the Cascades Arc. These rapidly built shield volcanoes are substantially larger than typically defined monogenetic volcanoes, yet both are wholly formed within a single ‘episode’ at the limits of temporal resolution. Paleomagnetic methods provide a high-resolution tool that can be applied to understanding the tempo of regional volcanism in arcs.

    Citation Information

    Publication Year 2023
    Title Paleomagnetically defined brief lifespans for two large shield volcanoes in the Cascades Arc
    DOI 10.1016/j.jvolgeores.2022.107740
    Authors Anthony Francis Pivarunas, Dawnika Blatter, L. J. Patrick Muffler, Michael A. Clynne, Andrew T. Calvert, Lauren N Harrison, R.L. Christiansen
    Publication Type Article
    Publication Subtype Journal Article
    Series Title Journal of Volcanology and Geothermal Research
    Index ID 70239842
    Record Source USGS Publications Warehouse
    USGS Organization Geology, Minerals, Energy, and Geophysics Science Center; Volcano Science Center