ORIGIN AND STRUCTURAL GEOMETRY OF FOLDING IN THE EUREKA-HOUSE SPRINGS STRUCTURE

The Eureka-House Springs structure exposed north of House Springs in eastern Missouri features deformation styles of faulting and folding. The structure is exposed along Highway 30 north of House Springs where bedding abruptly tilts to the southwest at dip angles higher than 35 degrees, inclinations uncharacteristic of eastern Missouri. In the area of most prominent folding several fault surfaces can be inferred and a prominent unconformity is also present. Several studies have investigated this structure and interpretation of the deformation style range from a positive flower structure to an asymmetrical anticlinal fold to a plunging monocline.

This study utilizes stratigraphic analysis and field measurements of attitudes of fault surfaces and bedding contacts to construct geologic cross sections. The outcrop measurements are combined with bedding contacts obtained from 73 water wells in the House Springs area. The cross sections are used to test different deformation styles (e.g., flower structure, drape folding, fault propagation folding, monoclonal folding) resulting in the observed deformation patterns.