GEOLOGIC MAP OF CASS COUNTY, MISSOURI

Cass County, located in west-central Missouri was mapped over an interval of 15 years by 50 graduate students enrolled in Geologic Mapping course 561 offered by the Department of Geosciences, University of Missouri-Kansas City. Two of the fourteen 7.5 minute quadrangles that give coverage to the county were mapped with grants awarded by the U.S. Geological Survey under The National Cooperative Geological Mapping Act, Educational Component (EDMAP) and gave us the experience and the incentive to map the entire county.

Cass County lies in the Scarped Plain, a providence within the Interior Lowland Region of the United States. The South Grand River and it's largest tributaries, have dissected the upland area into a system of rolling hills. Rocks of the Pennsylvanian Subsystem underlie the entire county and consist mostly of alternating beds of limestone and shale. The 120m (400ft) thick rock section consists of 85 named members and formations.

The regional dip is several feet per mile toward the structural axis of the Forest City basin, about 165 km (100 mi) northwest of the mapped areas. This is not a uniform dip. The strata have been "wrinkled" and form numerous small folds and faults. A major structure is the Belton Ring-fault complex, a circular-shaped area about 4.8 km (3 mi) in diameter where the strata are complexly folded and faulted and large blocks of strata have moved downward over 45 m (150 ft) along high angle faults formed by dissolution into the thick Mississippian limestone and dolomite beds that underlie the regolith at depths of several hundred feet, an interpretation based on the data from 4-test core boreholes.

The county is underlain by large reserves of industrial grade limestone but environmental concerns are increasingly preventing the exploitation of these resources as Metropolitan Kansas City moves southward into an area that is rapidly becoming suburbanized. The county population is over 100,000.

The map includes the subsurface stratigraphic column of Lower Paleozoic sedimentary rocks 600 m (2000 ft) thick that rest on Precambrian "basement" rocks. The inclusion of the subsurface rock section is intended to be an aid to organizations engaged in future investigations to locate favorable sites for deep underground installations or the occurrence of economic mineral deposits.