QUATERNARY MATERIALS ADJACENT TO THE GLACIATED MARGIN IN NORTH-CENTRAL OHIO

The surficial geology map of the Mansfield 30 x 60-minute quadrangle shows the complex Quaternary geologic history representative of the transition between the Till Plains, the Glaciated Allegheny Plateau, and the Unglaciated Appalachian Plateau physiographic regions in north-central Ohio. The map covers portions of eleven Ohio counties with four counties (Richland, Ashland, Crawford, and Morrow Counties) comprising 80% of the map. Data to generate the vertical and horizontal material variations and sequences shown on the map came from county soil surveys, water-well logs, oil and gas well logs, fieldwork, Ohio Department of Transportation and Ohio Environmental Protection Agency boring logs, and published and unpublished information from the Ohio Division of Geological Survey and other sources. One new GIS application developed during this project converts water well text descriptions into scaled-lithology stick figures. Plotting the lithology sticks on a GIS layer of soil parent material permitted rapid vertical and horizontal material analysis. An extensive history and distribution of pro-glacial lakes in the map area is indicated by numerous lacustrine or patchy lacustrine deposits as the topmost stratigraphic layer, particularly notable in the northwest quarter of the map. Analysis of the surface topography and buried fluvial drainage topography in the map area indicates a history of fluvial flow reversals and pro-glacial lakes breaching their impoundments, creating new outlet channels. The southeast quarter of the map area contains a relatively extensive deposit of sand and gravel that locally exceeds 100 ft in thickness and may represent a pre-Wisconsinan depositional event. The Mansfield 30 x 60-minute map completes surficial geology coverage along Ohio's Interstate 71 corridor and joins seven additional surficial geology maps covering the north-central and northeastern areas of Ohio. The eight surficial geology maps covering the northeastern quarter of Ohio will be a valuable asset for planning and development in this region. Mapping was partially funded by a U.S. Geological Survey STATEMAP grant.