Mattoon Anticline

Location

Northwestern Cumberland and western Coles Counties (F, G-7)

References

Clegg 1959, 1965b

Description

Clegg (1959) used borehole data on the Herrin and Danville Coal Members (Pennsylvanian) to define the Mattoon Anticline. The structure extends to all deeper mapped horizons, including the Beech Creek ("Barlow") Limestone (ISGS open files), the Ste. Genevieve Limestone (Bristol and Howard 1976), the New Albany Group (Stevenson et al.1981), and the Galena (Trenton) Group (Bristol and Buschbach 1973). Proprietary seismic-reflection data confirm that strata down to at least Upper Cambrian are folded. The Mattoon Anticline has a gently curved axis that trends slightly east of north. On the south, the fold plunges and dies out; northward, an offset saddle separates the Mattoon Anticline from the Cooks Mills Anticline. The Mattoon Anticline has closure of 60 to 70 feet (18-21 m) on the Pennsylvanian coals and similar relief (not precisely defined) at deeper horizons. The west limb is steeper than the east one.

The Mattoon Anticline is not generally considered to be part of the La Salle Anticlinorium, although its form and position suggest a genetic relationship.

The Mattoon Oil and Gas Field is developed along the anticline. The field has yielded nearly 22 million barrels of oil, principally from Cypress Sandstone and Ste. Genevieve Limestone reservoirs. Eleven billion cubic feet of gas from Devonian strata have also been produced. Mattoon field has been the largest commercial gas producer in Illinois.