Etchplain
An etchplain is a plain where the bedrock has been subject to considerable "etching" or subsurface weathering. Etchplanation is the process forming etchplains. Contrary to what the name might suggest, etchplains are seldom completely flat and usually display some relief, as weathering of the bedrock does not advance uniformly. This means that weathering is unrelated to the flatness which might be derivative of various other processes of planation including peneplanation and pediplanation.[1] Erosion of etchplains can result in the exposure of inselbergs such as bornhardt and tors.[2] Generally the topography exposed at a stripped etchplain, that is an etch surface,[3] after erosion of regolith is one with many irregularities as result of structurally defined areas of rock strength.[4]
A distinction can be made between etchplains and etch surfaces as the latter may or may not be flat and can represent the landform arising from the stripping of an etchplain.[3]
As climate changes, arid and semi-arid periods of pediplanation may alternate with more humid periods of etchplanation resulting in the formation of flattish surfaces (peneplains) of mixed origin (polygenetic).[5]
During wet seasons
The African Surface formed 70–40 million years ago is an example of an etchplain.[2]
History of the concept
The term 'etchplain' or 'etched peneplain' was originally coined to describe surfaces in
See also
- Strandflat – Type of landform found in high-latitude areas
- Sub-Mesozoic hilly peneplains – Landscape in Scandinavia of undulating hills and joint valleys
References
- ^ a b Migoń, Piotr (2004). "Etchning, etchplain and etchplanation". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. Routledge. pp. 345–347.
- ^ .
- ^ S2CID 128915651.
- ^ "Planation surface". Encyclopædia Britannica.
- doi:10.1086/628474.
- ^ Inselberg Formation Theories, The Geo Room
- ISBN 978-1118687437.