The Crawfordsville and Knightstown Moraines in Indiana

Abstract

The main advance of glacial ice into central Indiana during Wisconsin time had two distinct pulsations within a span of about 1,000 years. The first, about 21,000 years ago, reached farthest south and built the segmented Shelbyville Moraine near its margin. After this first advance, the ice melted somewhat and then readvanced to a new position a few miles short of its previous position about 20,000 years ago. Because the readvance crossed and buried the Champaign and Bloomington Moraines, these names should not be used for any of the few moraines that can be traced eastward out of the interlobate complex in west-central Indiana. The name Crawfordsville Moraine is proposed for the moraine that lies near the distal margin of the drift sheet left during the second ice advance. The Knightstown Moraine is the name given to a recessional moraine that was deposited later than the Crawfordsville Moraine and that merges with the continuation into eastern Indiana of the Farmersville Moraine of Ohio.