A
glacial lake is a
lake with origins in a melted
glacier. They are formed when a glacier erodes the land, and then melts, filling the hole or space that it has created. Near the end of the last
glacial period, roughly 10,000 years ago, glaciers began to retreat. A retreating glacier often left behind large deposits of ice in hollows between
drumlins or
hills. As the ice age ended, these melted to create lakes. This is apparent in the
Lake District in Northwestern
England where post-glacial sediments are normally between 4 and 6 metres deep. These lakes are often surrounded by
drumlins, along with other evidence of the glacier such as
moraines,
eskers and
erosional features such as
striations and
chatter marks.