Kettle (landform)

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Kettle lakes in Siberia, adjacent to the Gulf of Ob (image right). The different colors of the lakes reflect different amounts of sediment or depth; the deeper or clearer the water, the bluer the lake.

A kettle (or kettle hole) is a small, often round landform depression formed as a result of glacial movement. It is formed when a large piece of ice breaks away from the edge of a retreating glacier, and becomes partially buried under sediment deposited by the glacier. After it melts, this fragment leaves a small depression in the landscape.

A Kettle Pond or Kettle Lake is formed when water fills up the kettle hole.

The Kettle Moraine is a region of Wisconsin, covering an area from Green Bay to south-central Wisconsin, and has numerous kettles, moraines and other glacial features. It has many kettle lakes, some of which are 100 to 200 feet deep. Kettle Point, Ontario, a First Nation community on Lake Huron in Ontario, Canada has many examples of kettles, hence the name.

Pothole lakes dot the landscape of the Northern Hemisphere in the American and Canadian prairies, the Russian steppes, and throughout northern Siberia. Some of these lakes are far from agricultural land and settled areas, so they have fairly clear and unpolluted waters. Scientists use satellite images of these glacial kettle lakes to measure water clarity and to make environmental assessments. Scientists also monitor these lakes to study climate change. Researchers reported in Science that over the past 30 years, some glacial kettle lakes in northern Siberia have drained as the region has warmed and the permafrost beneath the lakes has "cracked," allowing lake water to drain out.

Kettle lakes are not fed or drained by rivers; they rely on percipitation to keep them from drying out.