During the final retreat of the ice sheet during the Wisconsinan glaciation, several types of landscape features were formed by deposition of glacial sediments. One of these types is an ice-contact feature known as a kame., which is present at Johnsonís Mound Forest Preserve. A kame is a steeply sided mound of glacial sediments composed mainly of sand and gravel deposits. The kame formed as the ice sheet stagnated and began to melt. A hole or depression within the ice was filled as a glacial stream carrying sediments flowed into the depression. Sediment continued to accumulate in the depression as the ice sheet melted. After the ice had melted, accumulated sediment was deposited as a mound on the landscape. Glacial deposits found in kames are usually stratified sands and gravel materials. The bedding features of the sediments are due to the natural sorting performed by the melt water streams flowing into the ice depression.
Click here for an activity that
can be used in a classroom setting to help students understsand the processes
which form a kame and how to identify them.