GIS APPLICATIONS IN BEDROCK MAPPING THE POPLAR BLUFF 30' X 60' QUADRANGLE, SOUTHEAST MISSOURI

The Bedrock Geologic Map of the Poplar Bluff 30’ X 60’ Quadrangle is a compilation of previously mapped 7.5’ quadrangles and interpretations of bedrock patterns and geologic structures based on well log data where bedrock exposure is poor. The collection of field data was performed using GPS technology while the compilation, integration, and presentation of the data was entirely done using Esri GIS software. The data was originally compiled using ArcView with no projection information included, thus requiring a projection to be defined. Some geologic features were reinterpreted by using well logs and outcrop data to eliminate any discrepancies in the map pattern along quadrangle boundaries. Some polygons mapped at 1:24,000 scale were merged or deleted for portrayal at 1:100,000 scale. Bedrock geologic maps of individual 7.5’ quadrangles were originally constructed by plotting field data, well logs, and mine and quarry data in ArcView 3.0 software. The locations and character of geologic contacts and structures were then identified or inferred. Stratigraphic columns, geologic cross-sections, and detailed descriptions of mappable units and structures were included on each 1:24,000 scale map. The resulting map pattern displays predominately flat-lying to gently dipping Cambrian-Ordovician units offset by generally NE-SW trending normal faults. Sporadic Precambrian igneous knob sare found as well as overlying Cenozoic sediments in the southeast. This STATEMAP funded project allows information to be made available to the public through printed maps and web based applications and serves as the foundational data upon which regional scale geologic interpretations are made. The web-based application GeoSTRAT provides geologic information housed at the Missouri Geological Survey accessible to the public.