1. Glacier Meltwater: As glaciers melt, they release large volumes of water. This water is often laden with sediment that the glacier has eroded from the surrounding landscape.
2. Meltwater Channels: The meltwater flows in channels that form on the surface of the glacier or at its edges. These channels often carry a high volume of water and sediment.
3. Deposition: As the meltwater flows away from the glacier, it loses energy and deposits its sediment load. This deposition occurs in a fan-shaped pattern at the glacier's edge, creating a plain.
4. Sediment Sorting: The sediment deposited by meltwater is often sorted by size. Larger, coarser sediment is deposited closer to the glacier, while finer sediment is carried further out.
5. Outwash Plain Formation: Over time, the deposition of sediment by meltwater creates a flat, gently sloping plain known as an outwash plain.
Characteristics of Outwash Plains:
* Flat and gently sloping: The surface of an outwash plain is typically flat or gently sloping, reflecting the deposition of sediment by meltwater.
* Well-sorted sediment: The sediment on an outwash plain is often well-sorted, with coarser sediment near the glacier and finer sediment further away.
* Kames and kettles: Outwash plains can also contain features such as kames (hill-like mounds of sediment) and kettles (depressions formed by the melting of blocks of ice).
* Stream channels: Outwash plains are often dissected by stream channels that carry meltwater away from the glacier.
Examples of Outwash Plains:
* The Sand Hills of Nebraska: This region in the central United States is a classic example of an outwash plain.
* The Puget Sound Lowland: This region in Washington state is also an outwash plain, formed by the melting of the Vashon Glacier.
Outwash plains are important features of glacial landscapes, and they provide valuable insights into the history of glacial activity.
