Turkey Run State Park: The power of erosion (GM-36)
About 20,000 years ago, when the last ice sheet that covered west-central Indiana began to waste away rapidly at the end of the Ice Age, streams of meltwater cut through the ice, through the soft deposits under the ice, and into the sandstone bedrock below. Carrying abundant loads of sand and gravel that were effective cutting tools, these streams quickly eroded narrow, steep-walled canyons in the rock.

Sugar Creek cut the largest canyon in this area, but stream deposits formed since the downcutting conceal many features formed by the running water. The Narrows, however, remains as visible evidence of the power of stream erosion. Lesser examples include the tributary canyons through which many of the trails run.

Look for potholes and the rounded cobbles that helped form them, along with scoured canyon walls and other evidence of stream erosion, as you walk through the scenic canyons of Turkey Run.

Our Hoosier State Beneath Us: Geomorphology