GIS-BASED ANALYSIS OF BEDROCK STRUCTURE AND DRAINAGE MORPHOMETRY IN THE RICHMOND SOUTH (KY) QUADRANGLE

To ultimately understand the structural control on drainage morphometry in the Richmond South (KY) Quadrangle, we conducted a GIS-based analysis of first-, second-, and third-order tributaries of the Kentucky River. Using ArcGIS, we digitized orthoimagery of the tributaries and incorporated a 20ft DEM to determine their span and orientation; focusing on the systematic trends that were found in the higher elevation areas within the quadrangle. This data, in conjunction with aerial photography and topographic maps, was used to determine optimal locations for physical examination of exposed bedrock alongside streambeds. Once located, we traversed the streams noting their orientations and identified jointing within the bedrock; measuring the orientations of these joints with a Brunton compass. After the necessary amount of stream and joint orientation data was collected it was plotted on rose diagrams via the program GeoRose. The resulting data likely suggest several dominating trends that seem to generally follow a northwesterly direction. Activity along several minor faults that lie between the Kentucky River and Irvine-Paint Creek Fault Zones, two branches of the Lexington Fault System, are likely the primary causes of this directional trend. These minor faults include the Richmond Fault, which lies within the Richmond North Quadrangle, and the Tates Creek Fault, which runs through the uppermost part of the Richmond South Quadrangle. The Lexington Fault System and its branches were likely created from tectonic stresses produced by the subsidence that formed the surrounding Appalachian and Ohio basins.