Esker

• Eskers are meandering ridges along a valley floor formed by melt water streams in/or under a glacier.
• As streams move through and out a glacier they lose power and energy, as a result they deposit material along the river bed.
• Eskers are made up of melt water sand and gravels, these are sorted by size.
• Heavier stones are dropped first by flowing water, lighter stones are carried further.
• The stones tend to be more rounded than glacial deposits as the act of moving water rounds their edges by erosion this process is called attrition.
• Attrition is when rocks are carried along by the meltwater and hit against each other creating smaller, rounder pieces.
• Upon reaching lower altitudes the glacier melts, and sub-glacial streams deposit material in the tunnel and an esker is left.