Old Woman Creek, Ohio

Old Woman Creek, Ohio

Geology

The bedrock underlying the Old Woman Creek watershed is composed of three different rock types, Ohio Shale, Bedford Shale and Berea Sandstone. Ohio Shale is the oldest formation, dating from the Devonian period. Bedford Shale and then Berea Sandstone were both deposited during the Mississippian Period. Ohio Shale is the predominant bedrock formation under the lakes plain, while the other two formations are largely confined to the escarpment and till plain areas of the watershed. It is only where the Old Woman Creek has eroded down through the escarpment that bedrock can be seen.

Glaciers have covered northern Ohio several times during the Pleistocene Period The final glacial retreat was approximately 14-15 thousand years ago. Following this retreat, various ice-dammed lakes were formed above present lake levels. The glacial till in the watershed appears to be either direct deposition from the ice shelf itself (till plain) or sedimentation in ice-dammed lakes (lake plain). The depth of glacial till deposition in the watershed is quite variable. The deepest deposits in the watershed are at the current mouth of Old Woman Creek. This appears to be the preglacial mouth of the Huron River. Here, glacial deposits are greater than 147 feet in depth.