SURFICIAL GEOLOGIC MAPPING IN EASTERN KENTUCKY: APPLICATIONS AND QUESTIONS

Surficial geologic mapping of Quaternary sediments in eastern Kentucky consists of analyzing topography, soils data, digital elevation models, mining data, aerial photography, and bedrock geology. GIS comparisons of existing data sets can highlight inconsistencies and relationships to create a powerful and efficient tool for new field work. GIS allows for the creation of detailed maps that are much more useful to transportation, geotechnical, energy, and hazard-mitigation audiences.

Active field mapping is delineating unconsolidated materials (engineering soils); the resulting map units represent genetic origin, lithology, and, where possible, thickness. Alluvium, colluvium, and residuum are the primary surficial units in eastern Kentucky. Minor units mapped include alluvial fans, terraces, and landslides. Areas disturbed by mining, construction, or excavation are also noted and delineated. KGS is collecting the necessary data to satisfy a variety of audiences that use different classification systems for their applications. For example, lithologic descriptions are collected that satisfy users of both the USDA soil classification and the Unified Soil Classification System.

Landslide susceptibility is also an application for this mapping. Landslides and unstable slopes damage existing infrastructure and cause millions of dollars in losses, discouraging economic development in eastern Kentucky. Landslides are commonly viewed as unpredictable, but knowledge of ground conditions (topography, geology, drainage) combined with well-planned construction can reduce exposure to the hazard and help to reduce landslide-related losses.

Delineating and describing material on both natural landscapes and disturbed areas has proven difficult for a variety of reasons. Highly variable grain sizes and thickness within colluvial slopes makes implementing a standard lithologic characterization difficult. The abundance of coal mining, much of it historical mining, presents a challenge to integrate details of mining activity into a surficial geologic map. Applying consistent field techniques to accurately describe and delineate surficial materials is crucial to satisfy varying users of surficial geologic maps.