COLUMBUS, OH -- A new topography map that dramatically depicts subterranean hills, valleys, and plains on Ohio's bedrock surface, is now available from the Ohio Department of Natural Resources (ODNR). Geologists, geotechnical consultants, land-use planners, ground water specialists, educators, and others interested in geotechnology will find many uses for the map that was digitally produced by the ODNR Division of Geological Survey. It is available in either a full-color, wall-sized version, or on CD-ROM in Geographic Information System (GIS) format. It is the result of a seven-year effort by geologists with the ODNR Division of Geological Survey to map the bedrock of Ohio. They compiled and digitized uppermost bedrock elevation contours and more than 158,000 data points during the work.
Ice-age glaciers advancing into western and northern Ohio smoothed and buried an ancient, complex surface that was significantly different from today's landscape. Erosion before, during, and after the glacial period created a bedrock surface that ranges from smooth to gorge-like. That bedrock surface, which is depicted on the map, is buried beneath glacial deposits commonly 25 to 50-feet thick, but sometimes attaining a thickness of more than 700 feet in portions of western Ohio.
One of the most striking features on the map is the remnant of the Teays River Valley, formed by a major north-flowing surface stream in southern and western Ohio prior to and throughout the time of the great glaciers. The now-buried Teays River Valley is clearly visible on the map, running between Scioto and Mercer counties. The main Teays River, and what were once its tributary streams, formed steep-walled gorges that range up to 400-feet deep and cut across the buried southern and western Ohio bedrock.
A paged-size version of the Shaded Bedrock-Topography Map Of Ohio is available for viewing or downloading from the ODNR web page at ohiodnr.com/geosurvey/new/new.htm . Copies of the detailed, wall-size version of the map may be ordered for $15, plus $4 handling (add $1.50 for mailing tube if map is to be sent rolled) and $1.02 tax (Ohio addresses only).
Orders for either the wall map or the CD-ROM version can be placed by calling 614-265-6576; or by writing the ODNR Division of Geological Survey, 4383 Fountain Square Drive, Columbus, OH 43224-1362.