Premium
An astronomical age for the Bishop Tuff and concordance with radioisotopic dates
Author(s) -
Zeeden Christian,
Rivera Tiffany A.,
Storey Michael
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl059899
Subject(s) - geology , sanidine , quaternary , geochronology , sedimentary rock , paleontology , paleomagnetism , zircon , chronostratigraphy , absolute dating , lava , stage (stratigraphy) , horizon , earth's magnetic field , volcano , biotite , quartz , physics , astronomy , quantum mechanics , magnetic field
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 40 Ar/ 39 Ar 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 238 U/ 206 Pb zircon and 40 Ar/ 39 Ar 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 δ 18 O global benthic stack and its age model. This age is consistent with Bishop Tuff radioisotopic ages, including new single crystal 40 Ar/ 39 Ar sanidine fusion analyses presented here, which demonstrates that concordance through multiple dating techniques is achievable within the Quaternary.