An astronomical age for the Bishop Tuff and concordance with radioisotopic dates

Tiffany Rivera, Christian Zeeden, Michael Storey

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

    Abstract

    The Bishop Tuff forms a key stratigraphic horizon for synchronization of Quaternary sedimentary records in North America. The unit stratigraphically overlies the Matuyama-Brunhes geomagnetic polarity reversal by several thousand years; high-precision dating of this tuff may be valuable for regional and global correlation of records. The Quaternary time scale is anchored by 40Ar/39Ar ages on lava flows and ash layers where available, with stage boundaries and geomagnetic reversals including astronomically tuned records. However, astronomical dating has not yet validated the high-precision 238U/206Pb zircon and 40Ar/39Ar sanidine ages of the Bishop Tuff. We have identified the Bishop Tuff within the marine sedimentary record and derived an astronomical age of 0.765 ± 0.008 Ma by correlation to the LR04 δ18O global benthic stack and its age model. This age is consistent with Bishop Tuff radioisotopic ages, including new single crystal 40Ar/39Ar sanidine fusion analyses presented here, which demonstrates that concordance through multiple dating techniques is achievable within the Quaternary
    OriginalsprogEngelsk
    TidsskriftGeophysical Research Letters
    Vol/bind41
    Udgave nummer10
    Sider (fra-til)3478-3484
    ISSN0094-8276
    DOI
    StatusUdgivet - 2014

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