MULTI-TECHNIQUES GEOLOGIC AND GEOMORPHOLOGIC MAPPING OF THE BEDROCK OUTCROPS WITHIN THE MCDANIELS QUADRANGLE, ROUGH CREEK GRABEN, KENTUCKY

The McDaniels Quadrangle is a northeastern continuation of the Cambrian-age Rough Creek Graben within Kentucky. Lack of proper understanding of the depositional history and complex structures of the Paleozoic rocks was the motivation for a 1:10,000 geologic mapping project, supported by USGS EDMAP program. Standard geologic field methods, thin section petrography, core analysis, and high-resolution remote sensing and topographic data analyses were utilized to map geologic structures, lithology, stratigraphic contacts, and geomorphology. Sentinel-2 images and 1.5m LiDAR DEM were used to guide field mapping, and extract river profiles using MATLAB-based stream power-law codes. Using these multiple datasets, an interactive digital geologic map is created at a higher resolution than the published 1978 map, with additional information such as lithologs, depositional environments, and paleontological, structural, and geomorphological data.

The study area is composed of mostly sandstone, shale, and limestone, with characteristic sedimentary structures such as double mud-drapes, tidal bundles, herringbone cross-stratification, and hummocky cross-stratification. The depositional environments are interpreted to represent shallow-marine, coastal-plain, and incised valleys, with the tide, wave and storm-dominated systems. Thin-section petrographic analysis shows that sandstone units are ferruginous with dominantly quartz grains and iron oxide. The limestone units have a variety of textures, including mudstone, grainstone, and oolites. The area is structurally controlled by two NE- and E-trending fault zones associated with the Rough Creek Graben. Field and remote sensing-based structural analysis reveals a predominant NE-trending mesoscale structure. The river longitudinal profile analysis reveals geomorphological signals recorded by knickpoint distribution in a bedrock-controlled system. Our geologic map of the McDaniels Quadrangle provides a necessary update to an old map with more detailed insights for stakeholders to anticipate potential hazards, plan construction projects, and gain a deeper knowledge of both the surface and subsurface features of the area.