Peneplain

File:Sanikiluaq peneplain.JPG

Aerial view of the almost flat and drowned peneplain at Belcher Islands, Hudson Bay, Canada. Note that the peneplain cuts across numerous folds.

In geomorphology and geology a peneplain is a low-relief non-constructional plain. This is the definition in the broadest of terms, albeit with frequency the usage of peneplain is meant to imply the representation of a near-final (or penultimate) stage of fluvial erosion during times of extended tectonic stability. Peneplains are sometimes associated with the cycle of erosion theory of William Morris Davis.

The existence of some peneplains, and peneplanation as a geomorphological process, is not without controversy, due to a lack of contemporary examples and uncertainty in identifying relic examples. By some definitions peneplains grade down to a base level represented by sea level, yet in other definitions such a condition is ignored. A common misconception about peneplains is that they ought to be featureless.

Canisteo River Valley from Pinnacle State Park, New York. The distant peaks at the same elevation represent the remnants of a peneplain that was uplifted to form the Allegheny Plateau, which is a dissected plateau in southwestern New York. In this area, the sharp relief that is seen on some of the Allegheny Plateau has been rounded by glaciation.

See also

• Erosion surface
• Planation surface
• South Småland peneplain
• Sub-Cambrian peneplain
• Summit accordance