[2] At its center beneath southern Illinois, the basin contains a thickness of about 15,000 feet of Cambrian through Pennsylvanian sedimentary rocks, predominantly marine, and mostly dolomite, limestone, shale, and sandstone.

Bituminous coal is present in Pennsylvanian rocks in the basin, deposited in freshwater swamp environments.

[6] Coal production was 99 million short tons in 2008, roughly equally divided between Illinois, Indiana, and western Kentucky.

In 2009, Archer Daniels Midland Corp. began pilot testing the carbon sequestration potential of the Mt.

[10] As of January 2015, one million metric tons of carbon dioxide had been sequestered in the Illinois Basin-Decatur Project.