Joachim Dolomite
| Joachim Dolomite | |
|---|---|
| Stratigraphic range: Ordovician | |
Joachim Dolomite over St. Peter Sandstone (Pacific, Missouri) | |
| Type | Formation |
| Unit of | Ancell Group |
| Underlies | Pecatonica Formation and Plattin Limestone |
| Overlies | St. Peter Sandstone |
| Thickness | 0 to 100+ feet in Arkansas |
| Lithology | |
| Primary | dolomite |
| Location | |
| Region | Arkansas, Illinois, Missouri |
| Country | United States |
| Type section | |
| Named for | Joachim Creek, Jefferson County, Missouri |
| Named by | Arthur Winslow |
The Joachim Dolomite is a Middle Ordovician geologic formation in Arkansas, Illinois, and Missouri. The name was first introduced in 1894 by Arthur Winslow in his study of the geology of Missouri. Winslow designated a stratotype along Plattin Creek, which was misidentified as Joachim Creek, in Jefferson County. The name was introduced into Arkansas in 1911, replacing part of the, now abandoned, Izard Limestone.