Planation surface

In geology and geomorphology a planation surface is a large-scale surface that is almost flat with the possible exception of some residuals hills. The processes that forms planation surfaces are labelled collectively planation and are exogenic (chiefly erosion). Planation surfaces are planated disregarless of bedrock structures. In Earth they constitute some of the most common landscapes. Peneplains, pediplains, etchplains are proposed types of planation surfaces planated by "peneplanation", "pediplanation" and "etchplanation". In addition to these there are planation surfaces proposed to be formed by cryoplanation, marine processes, areal glacial erosion and salt weathering. The term planation surface is often preferred over other because some more specific planation surface types and processes remain controversial.