Stratigraphic Units
You need to learn the characteristics of the different stratigraphic units before we go into the field. In your field notebooks, make a stratigraphic column showing the different members, formations, groups, and their assigned ages.
Light yellow, micaceous sandstones (note characteristic piping) and light grey-white claystones of the Golden Valley Formation capped by the darker grey claystones of the South Heart Member of the Chadron Formation.
(Photo Allan Ashworth)
Cemented sandstones of the Chalky Buttes Member of the Chadron Formation.
(Photo Allan Ashworth)
What stratigraphic units are represented in this butte?
(Photo Allan Ashworth)
Light brown mudstones of the Brule Formation
(Photo B. Saini-Eidukat)
Fossil of an oreodont skull from the Brule Formation.
(Photo Allan Ashworth)
Popcorn weathered claystones of the South Heart Member of the Chadron Formation in the "haystack butte" in the foreground. The South Heart Member overlies the light grey sandstones and claystones of the Chalky Buttes Member.
What is the yellow colored formation in the background?
(Photo Allan Ashworth)
Acknowledgment: Web site and course info based on material developed by Allan Ashworth