CAN GEOLOGIC MAPS BENEFIT FROM SOILS DATA? AN EXPLORATIVE INVESTIGATION OF BEDROCK AND SURFICIAL GEOLOGIC MAPS IN NASH COUNTY, NORTH CAROLINA
Soil map units can be sorted based on the geologic material from which they formed. While geologic data embedded in soil maps are typically broadly categorized (i.e. basic rock types), soil maps have potential to provide refinement of geologic map units in certain applications. We selected two USGS 1:24,000 quadrangles in Nash County, North Carolina based on recent work on Tertiary sedimentary deposits and associated soil relationships in this region (Stadelman SEGSA 2017). Nash County is located in the Fall Line Zone between the eastern piedmont and inner coastal plain of North Carolina about 40 miles east of Raleigh. Bedrock geology consists of Paleozoic metavolcanics and igneous intrusive rocks overlain by Tertiary sediments.
GIS analysis of geologic and soil survey maps indicated good potential to improve delineation of bedrock map units in Nash County and especially boundaries between metavolcanics and intrusive igneous map units. This analysis also indicated high potential for improvement in delineation of sedimentary deposits. Field investigations were done in selected areas, and results with preliminary geologic map revisions will be presented.