Stratigraphic framework of the Absaroka volcanic supergroup in the Yellowstone National Park region
Smedes HW and Prostka HJ. 1972. Stratigraphic framework of the Absaroka volcanic supergroup in the Yellowstone National Park region. U.S. Geological Survey (USGS) Professional Paper. Series Volume Number: 729-C. United States Government Printing Office. Washington, DC
This is a brief description of the stratigraphy of the Eocene Absaroka volcanic field, Wyoming and Montana. The Absaroka Volcanic Supergroup, three groups, five formations, and five members are defined. This report briefly describes the stratigraphy of the Absaroka volcanic field in and near Yellowstone National Park. The volcanics, mainly andesitic, basaltic, and dacitic volcaniclastic rocks, are herein named the Absaroka Volcanic Supergroup. The supergroup comprises, from oldest to youngest, the Washburn Group, Sunlight Group, and Thorofare Creek Group (new names). Within these groups, the following five new formations and five new members are defined: In the Washburn Group- Sepulcher Formation and its Daly Creek and Fortress Mountain Members, and Lamar River Formation. In the Sunlight Group- Mount Wallace Formation and its Slough Creek Tuff Member, and the Pacific Creek Tuff Member (of the Trout Peak Trachyandesite). In the Thorofare Creek Group -Langford Formation and its Promontory Member, and the Two Ocean Formation. The usage of some formerly established units is modified on the basis of new data, and correlations with rocks in outlying parts of the volcanic field are proposed. This stratigraphic framework has been established by mapping of lithologic units and by potassium-argon age data and fossils.
- Type
- Published Report
- Authors
- Smedes, Harry; Prostka, Harold
- Date of Issue
- 1972
- Publisher
- United States Government Printing Office
- Units
- HIST , YELL
- Keywords
- Basalts, Distribution, ehistory, Formation, Formations, Geology, Geomorphology, History, Rocks, Sedimentary Rock, Stratigraphy, Sunlight Group, Throrofare Creek Group, Volcanic Rocks, Washburn Group