An erosional plain is a relatively flat landform created by the long-term wearing down (erosion) of elevated or upland areas.
Understanding Erosional Plains
Erosional plains, sometimes referred to as peneplains (meaning "almost a plain"), are characterized by their generally flat or gently undulating surface. This flatness is the result of extensive erosion over vast periods. Unlike depositional plains which are built up by sediment, erosional plains are carved out of existing land.
Formation of Erosional Plains
The formation process typically involves:
- Uplift: An area of land is uplifted, exposing it to the elements.
- Erosion: Various agents of erosion, such as rivers, wind, glaciers, and chemical weathering, begin to wear down the land surface.
- Gradual Reduction: Over time, these erosional forces gradually reduce the elevation of the land, smoothing out irregularities and creating a relatively flat surface.
Characteristics of Erosional Plains
- Relatively Flat Surface: The most defining feature.
- Undulating Topography: They are hardly smooth and possess an undulating or rolling surface due to varying resistance of the underlying rock.
- Dissected by Streams: Often crossed by numerous streams and rivers that further contribute to the erosional process.
- Resistant Rock Outcrops: May contain isolated hills or ridges (monadnocks) composed of more resistant rock that have survived the erosion process.
Examples of Erosional Plains
- Canadian Shield: A vast area of exposed Precambrian rock in eastern and central Canada, shaped by glacial erosion over millions of years.
- West Siberian Plain: A large plain in Russia, formed by a combination of erosion and deposition but with significant erosional components.
In summary, an erosional plain is a landform shaped by the gradual removal of material from an upland area through erosion, resulting in a relatively flat or gently rolling surface.
