MAP DETAIL from
"Map Showing the Thickness and Character of Quaternary Sediments in the Glaciated United States East of the Rocky Mountains"
U.S. Geological Survey Miscellaneous Investigations Series Map I-1970
1993-1998
by David R. Soller
Especially as the glaciers retreated, the Wabash River served as a conduit for glacial meltwater and coarse-grained sediment. The large volumes of sediment in the river channel caused tributary valleys to be dammed, thereby creating lakes which became filled with finer-grained sediment. These images show these features in the lower Wabash River near its confluence with the Ohio River. In the westernmost tributary valley, buried sand and gravel are shown by yellow dots. This area is near the glacial margin (shown by the red line), and the upland glacial deposits are thin. Sediments in the tributaries has been shown to liquefy during earthquakes, and this map has been used in the field to identify areas to search for pre-historic liquefaction features.
