Geologic mapping is basic to the Survey's mission, and provides the starting point for other geologic studies. Geologic maps are used to evaluate mineral resources, such as coal, oil and gas, metallic and industrial minerals, and groundwater. Maps are valuable to planners and engineers in providing information on properties of earth materials, potential geologic hazards, and environmental conditions. Maps currently complete or in progress extend from Grafton and Alton on the north to Columbia on the south. Mapping focuses on geologic hazards that will affect development, among them landslide-prone areas, karst features, and subsidence due to abandoned underground mines.
Mapping also highlights valuable mineral resources, including limestone, coal, oil, and gas.
We are presently mapping the Karnak, Olmsted, and Cairo Quadrangles at the southern tip of the state. These faults are closely tied to the New Madrid Seismic Zone, a short distance south of Illinois.