Oil and gas, lignite, and potash. Mild tectonic distortion during Phanerozoic related to movement of Precambrian basement blocks. Sedimentary rocks of cratonic sequences Sauk through Tejas are present in the basin. Depositional environments throughout Sauk, Tippecanoe, and Kaskaskia deposition were largely shallow marine. Subtidal and even basinal environments were developed in the basin center, but sabkha deposits were abundant near the basin periphery. Subaerial weathering, pinnacle reefs. Major structures in the basin may result from left-lateral shear along the Colorado-Wyoming and Fromberg zones during pre-Phanerozoic time; renewed movement or "tensing" of pre-Phanerozoic faults. Meteorite impact events have been suggested as the origin for one or more structures.--Modified journal abstract.