Glaciers produce a variety of distinctive landforms as they deposit the sediment and debris they carry.
As glaciers advance, they pick up and transport vast quantities of rock and sediment, known collectively as glacial drift. When glaciers melt, either due to climate change or seasonal variations, this transported material is deposited. The deposition can happen directly from the ice (forming till) or via meltwater streams flowing from or beneath the glacier (forming stratified drift). These processes create unique geological features on the landscape.
Key Glacial Depositional Landforms
Based on glacial processes, several notable landforms are created through deposition. These include:
- Drumlins: These are streamlined, elongated hills composed of till, typically oriented parallel to the direction of ice flow. They often occur in groups called drumlin fields.
- Erratics: These are large rocks or boulders that have been transported by a glacier and deposited in an area where the underlying bedrock is different. They stand out from the surrounding landscape.
- Moraines: These are ridges or mounds of till deposited along the margins of a glacier. Different types exist, such as terminal moraines (marking the farthest extent), lateral moraines (along the sides), medial moraines (formed where two glaciers merge), and ground moraines (a sheet of till left behind as the ice melts).
- Outwash Plain: A broad, flat area formed by glaciofluvial deposits. Meltwater streams flowing from the glacier carry and sort sediment, depositing finer material further from the ice front.
- Esker: A long, winding ridge composed of stratified sand and gravel. Eskers form within tunnels or channels under, within, or on top of melting glaciers where meltwater streams deposit sediment.
- Kettle: A shallow, sediment-filled body of water or a depression in glacial outwash. Kettles form when a block of glacial ice is buried by sediment and later melts, leaving a depression.
- Kame: An irregular hill or mound composed of stratified sand and gravel. Kames typically form where meltwater collects and deposits sediment in depressions on the glacier surface or along its margins.
These landforms provide significant evidence of past glaciation and offer insights into the dynamics of ancient ice sheets and glaciers.
