Peneplain

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.

[4] In fact, some peneplains may be hilly as they reflect irregular deep weathering, forming a plain grading to a base level only at a grand-scale.

[5] In their 2013 work Green, Lidmar-Bergström and co-workers provide the following classification scheme for peneplains:[5] Rhodes Fairbridge and Charles Finkl argue that peneplains are often of mixed origin (polygenetic), as they may have been shaped by etchplanation during periods of humid climate and pediplanation during periods of arid and semi-arid climate.

Further, alternation of processes with varying climate, relative sea level and biota make old surfaces unlikely to be of a single origin.

[3] Peneplains that are detached from their base level are identified by either hosting an accumulation of sediments that buries it or by being in an uplifted position.

As Davis put it in 1885:[16] Uplifted peneplains can be preserved as fossil landforms in conditions of extreme aridity or under non-eroding cold-based glacier ice.

[17][18] In the Fennoscandian Shield average glacier erosion during the Quaternary amounts to tens of meters, albeit this was not evenly distributed.

[18] For glacier erosion to be effective in shields a long "preparation period" of weathering under non-glacial conditions may be a requirement.

Aerial view of the almost flat and drowned peneplain at Belcher Islands , Hudson Bay, Canada, cutting across numerous geologic folds .
Sketch of a hypothetical peneplain formation after an orogeny .
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 .
The Hardangervidda plateau in southern Norway is a peneplain formed in the Miocene epoch and then uplifted to its present altitude of 1200 m a.s.l. [ 14 ]