BEDROCK MAP OF THE KARBERS RIDGE 7.5 MINUTE QUADRANGLE, GALLATIN AND HARDIN COUNTIES, ILLINOIS

The Karbers Ridge 7.5 Minute Quadrangle is located within the west longitudes of 88° 22' 30'' and 88° 15' and the north latitudes of 37° 37' 30'' and 37° 30' in southeastern Illinois. Geologic mapping is being conducted as a continued effort to produce 1:24,000-scale quadrangle maps of the entire state of Illinois. The Karbers Ridge Quadrangle is being mapped to further elucidate the Mississippi Valley Type (MVT) fluorite deposits, and associated ultramafic igneous breccia and diatremes located within this quadrangle. The ultramafic igneous rocks are highly altered and will be examined through standard optical, geochemical, and electron microscopic methods in order to classify the igneous rocks. The tectonics of the region will be examined to identify potential targets for new mineral exploration projects. Techniques for producing this map consisted of field observations and corresponding interpretations, drilling, and subsequent logging of several holes and the use of ArcGIS in the creation of the final copy of the map. Funding for this project was provided by the United States Geological Survey STATEMAP program and the Illinois State Geological Survey.