Wells Creek
Key facts
- Country
- United States
- Diameter
- 12 km
- Age
- about 200 ± 100 million years
- Location
- 36.38° N, 87.67° W
A round pattern of ridges and valleys about 12 km across in the wooded hills of northern Tennessee, near the town of Erin. Shatter cones occur in outcrops in the centre.
Wells Creek is an eroded impact structure about 12 km across in Houston and Stewart counties, northern Tennessee, in the United States. It is a textbook example of a complex crater with a central uplift and rings of faulted rock.
What it hit. The target was a thick sequence of Palaeozoic sedimentary rocks, mainly limestones, dolomites and shales of Ordovician to Mississippian age. In the centre, the rebound of the crater floor lifted Ordovician rocks hundreds of metres above their normal position. Around the uplift, rings of down-dropped and folded rock created the pattern of ridges and valleys seen today.
Age. The age is poorly known. The youngest rocks affected are Mississippian, about 330 million years old, and no younger rocks lie across the structure to fix a lower limit. The age is therefore usually given only roughly, as about 200 million years plus or minus 100 million.
Proof of impact. Wells Creek has abundant shatter cones, cone-shaped fractures that form only under the shock of an impact, some of them very large and well formed. The structure was mapped in great detail in the 1950s and 1960s by geologists who had long suspected a cryptovolcanic origin; the shatter cones and other shock features showed that an impact was responsible.
Why it matters. Wells Creek is one of several old impact structures in the eastern United States that formed in layered sedimentary rock, and its detailed maps help geologists understand how such craters collapse. The impactor is unknown.
Visiting. Most of the area is private land and farmland. Ask landowners' permission before searching for shatter cones.
Did you know?
Wells Creek has some of the best shatter cones in North America.
Its age is uncertain by about 100 million years either way.
Rocks in the centre were lifted hundreds of metres above their usual level.