- journal_title：Geological Society of America Bulletin
- Contributor：Marvin A. Lanphere ; Duane E. Champion ; Robert L. Christiansen ; Glen A. Izett ; John D. Obradovich
- Publisher：Geological Society of America
- Date：2002-
- Format：text/html
- Language：en
- Identifier：10.1130/0016-7606(2002)114<0559:RAFTOT>2.0.CO;2
- journal_abbrev：Geological Society of America Bulletin
- issn：0016-7606
- volume：114
- issue：5
- firstpage：559
40Ar/39Ar ages were determined on the three major ash-flow tuffs of the Yellowstone Plateau volcanic field in the region of Yellowstone National Park in order to improve the precision of previously determined ages. Total-fusion and incremental- heating ages of sanidine yielded the following mean ages: Huckleberry Ridge Tuff—2.059 ± 0.004 Ma; Mesa Falls Tuff— 1.285 ± 0.004 Ma; and Lava Creek Tuff— 0.639 ± 0.002 Ma.
The Huckleberry Ridge Tuff has a transitional magnetic direction and has previously been related to the Reunion Normal- Polarity Subchron. Dating of the Reunion event has been reviewed and its ages have been normalized to a common value for mineral standards. The age of the Huckleberry Ridge Tuff is significantly younger than lava flows of the Reunion event on Ré union Island, supporting other evidence for a normal-polarity event younger than the Reunion event.