Pickneyville Anticline

Location

Central Perry County (I-5)

References

Bell et al. 1931, Cady et al. 1938

Description

Bell et al. (1931) defined the Pinckneyville Anticline largely on the basis of elevation surveys from underground mines in the Herrin Coal Member. The fold trends due north and has a relatively steep west flank and a gentle east limb. It plunges abruptly at the south end and gently at the north end. Closure is indicated to be about 60 feet (18 m). Bell et al. (1931) stated that a normal fault was encountered in mines about 0.75 mile (1.2 km) west of the anticlinal crest. The fault strikes due north and the east side is downthrown 28 feet (8.5 m) in a mine in the northeast quarter of Section 26, T5S, R3W. They noted that the fault is parallel to the Du Quoin Monocline and suggested that it developed under the same stresses.

Cady et al. (1938) mapped the anticline essentially the same as did Bell et al. (1931), but they did not show the fault. The Pinckneyville Anticline persists in Mississippian strata. A map of the top of the Karnak Limestone (R. Howard, unpublished mapping) shows an anticline with closure of 40 to 60 feet (12-18 m) essentially as mapped on the coal.