GEOLOGIC MAPPING AT THE MISSOURI DEPARTMENT OF NATURAL RESOURCES, DIVISION OF GEOLOGY AND LAND SURVEY

The Missouri Department of Natural Resources, Division of Geology and Land Survey archives and publishes geologic mapping for the state of Missouri. Currently, over 14,000 square miles of the state have been mapped at a scale of 1:24,000. This includes mapping by various agencies and universities. The majority of this detailed mapping has been done in the Ozark Plateaus region. The division also continues to create new geologic mapping for 7.5 minute quadrangle areas at a scale of 1:24000. Both surficial and bedrock maps are produced. Each mapping geologist at the Missouri Division of Geology and Land Survey takes their map from the initial entry of field data to the final open file product.

Field procedures are currently transitioning from pens and paper maps to ArcPad and a field notebook computer. The geologist collects data by observing outcrops along roads, streams and hillsides throughout the area of investigation, with a target number of 660 control points per quadrangle. In the office, ArcMap is used to prepare outcrop maps and databases with information on map unit name, lithology and structures. Support data located in office files is collected in a similar manner. Digital raster images of USGS 1:24000 scale topographic maps are used as base maps.

The data is interpreted and the geologic map is compiled in ArcMap as a set of shapefiles. Bedrock contacts are drawn as polygon boundaries. Geologic structures are represented as lines and points. Internal standards have been developed for attributes. All components of the map layout are produced in ArcMap, including cross sections, correlation tables and stratigraphic columns. Microsoft Word is used to create text that is later inserted into the “unit description” section of the layout. A layout template is used to standardize appearance of the maps, but the variable length of unit descriptions and cross sections require flexibility of the map layout design.

Images of the maps are stored in PDF or JPEG format. The images are open filed and printed on demand or sold on CD to the public. Metadata is created for the geologic map shapefiles and stored for future revision or compilation.