Geologic Mapping Program

Geologic mapping at the scale of 1:24,000 is one of the primary activities of the ISGS. To map an area, geologists examine and sample exposures of rocks and earth materials in stream banks, road cuts, mines, and quarries. They examine all available well records for the area and drill additional holes to obtain core samples. Data are complied on USGS 7.5-minute topographic maps and published in one of the ISGS map series. The map-making process is computerized, and maps are available to the public in digital and printed form.

ISGS geologist, Joe Devera explaining the geology to local landowners

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.

St. Louis Metro East Area

A team headed by Joe Devera is mapping this area, which is undergoing rapid population growth. 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.