Geochronology of the late Cenozoic volcanism of Yellowstone National Park and adjoining areas, Wyoming and Idaho
Obradovich JD. 1992. Geochronology of the late Cenozoic volcanism of Yellowstone National Park and adjoining areas, Wyoming and Idaho. U.S. Geological Survey (USGS) Open-File Report. 92-408. United States Geological Survey. Denver, CO
Yellowstone National Park and surrounding regions were the scene of two major episodes of volcanism in the early and latter parts of the Cenozoic. The geochronology of the earliest of these volcanic episodes (the Absaroka Volcanic Supergroup) will be dealt with elsewhere. It is the purpose of this report to document the chronology of the volcanism of the three major eruptive phases of the Yellowstone Volcanic Province. This has been an ongoing study and often the geologic relationships as mapped and the geochronology have been at variance. Only through additional studies both in the field and in the laboratory have most of these differences been resolved. The evolution in methodology employed is detailed in Appendix I but it is sufficient to note that the isotopic analyses showing the smallest analytical uncertainty generally reflect the more recent analyses and the more advanced technologies of the time. In the course of this study more than 200 age determinations were made and 170 of these are reported here.
- Type
- Published Report
- Authors
- Obradovich, John
- Date of Issue
- 1992
- Publisher
- United States Geological Survey
- Units
- HIST , YELL
- Keywords
- Cenozoic, central plateau, Dating, ehistory, eruptive history, Geology, History, Obsidian Creek, Roaring Mountain, Sediments, Stratigraphy, Tephra, Upper Basin, Volcanic Formations