ANNUAL WORKFLOW OF THE STATEMAP-FUNDED DIGITAL SURFICIAL GEOLOGIC MAPPING PROGRAM AT THE KENTUCKY GEOLOGICAL SURVEY

The Kentucky Geological Survey has been producing surficial geologic maps as part of the U.S. Geological Survey’s STATEMAP program since 2004. The goal for each geologist involved is to produce an accurate surficial map of one 7.5-minute quadrangle each year; this includes a 1:24,000-scale paper product and a GIS database.

Our mapping cycle begins with a review of existing data and relevant publications, creation of a standardized geodatabase in the NCGMP09 format, and compilation of and digitizing subsurface information on water wells and oil and gas wells, and from geotechnical reports and other sources.

Base maps are then compiled for each quadrangle, which include orthoimagery, digital elevation models, slope maps, and contours (10-, 5-, and 2-ft intervals) derived from LiDAR (1-m resolution). Contacts between residuum, colluvial slopes, artificial fill, alluvium, alluvial fans, and terraces are often apparent from LiDAR derivatives and are constructed. This digital data collection is uploaded to ArcGIS Online and made available to each geologist through a mobile device loaded with the ESRI Collector app.

Field work throughout the remainder of the year assesses questionable features, confirms contacts and units, and obtains material characterization data such as color, grain size, soil development, thickness, and spatial extent. Many of these data are instantly recorded using Collector and updated in our database. A truck-mounted Geoprobe is used to obtain core samples and determine depth to bedrock. As field work progresses, contacts and units are updated and digitized.

Outcrops or cores suitable for optically stimulated luminescence or cosmogenic radionuclide geochronology are also identified or collected; at least a 6-month window is ideal to incorporate results into our final product.

Near the end of the cycle, preliminary drafts are produced, followed with field reviews to check the accuracy and completion of the map, as well as establish a consensus among geologists. Reviews are incorporated into a final version, reviewed by our internal editor, and delivered to the USGS.

This workflow helps us maintain consistency, identify areas of potential concern for further investigation, and produce high-quality 1:24,000-scale surficial geologic quadrangle maps in one year.