The existence of some peneplains, and peneplanation as a process in nature, 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
While peneplains are usually assumed to form near sea level it has also been posited that peneplains can form at height if extensive sedimentation raises the local base level sufficiently or if river networks are continuously obstructed by
A common misconception about peneplains is that they ought to be so plain they are featureless. In fact, some peneplains may be hilly as they reflect irregular deep
There are various terms for landforms that are either alternatives to classical peneplains, a sub-set of peneplains or partially overlap with the term. The last is the case of planation surfaces that may be peneplains or not, while some peneplains are not planation surfaces.
In their 2013 work Green, Lidmar-Bergström and co-workers provide the following classication scheme for peneplains:
In addition epigene peneplains can be distinguished from exhumed peneplains. Epigene are those that have never been buried or covered by sedimentary rock. Exhumed peneplains are those that are re-exposed after having been buried in sediments.
The peneplain concept is often juxtaposed to that of
According to King pediplains main difference to Davis’ peneplains is in the history and processes behind, and less so in the final shape. A difference in form that may be present is that of residual hills which in Davis’ peneplains are to have gentle slopes while in pediplains they ought to have the same steepness as the slopes in the early stages of erosion leading to pediplanation. Given that the coalesced