Pediplain
In geology and geomorphology a pediplain (from the Latin pes, genitive case pedis, meaning "foot") is an extensive plain formed by the coalescence of pediments.[1] The processes through which pediplains forms is known as pediplanation.[2] The concepts of pediplain and pediplanation were first developed by geologist Lester Charles King in his 1942 book South African Scenery. The concept gained notoriety as it was juxtaposed to peneplanation.[3][A]
The coalesced pediments of the pediplains may form a series of very gentle concave slopes.[B] Pediplains main difference to W. M. Davis’ peneplains is in the history and processes behind, and less so in the final shape. Perhaps the most notable 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.[4]
Pediplanation is linked to scarp retreat in the following way: as scarps retreat over geological time pediments migrate and extend over large areas. The result is that the surface is eroded chiefly backward and that downward erosion is limited.[1][3] In contrast to common peneplain conceptualizations several pediplains might form simultaneously at different altitudes and do not necessarily grade to a base level.[2] Pediplains are normally formed in areas of arid and semi-arid climate.[5] 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).[6]
Cryoplanation is a variant of pediplanation that is restricted to cold climates.[2]
Examples
See also
Notes
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- ^ King himself held that: : A peneplain in the Davisian sense, resulting from slope reduction and downwearing, does not exist in nature. It should be redefined as "an imaginary landform."[4]
- ^ It is argued by T.J. Fair that peneplains also have these gentle concave forms, but W. M. Davis’ view on the issue is not clear, meaning possibly that he might have held that peneplains had very gentle convex slopes.[4]
References
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- ^ a b Page Module:Citation/CS1/styles.css has no content.Jones, David K.C. (2004). "Denudation chronology". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. pp. 244–248.
- ^ a b c Page Module:Citation/CS1/styles.css has no content.Migoń, Piotr (2004). "Planation surface". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. pp. 788–792.
- ^ a b Page Module:Citation/CS1/styles.css has no content.Twidale, C.R. (1992). "King of the plains: Lester King's contributions to geomorphology". Geomorphology. 5 (6): 491–499. Bibcode:1992Geomo...5..491T. doi:10.1016/0169-555x(92)90021-f.
- ^ a b c Page Module:Citation/CS1/styles.css has no content.King, L.C. (1953). "Canons of landscape evolution". Geological Society of America Bulletin. 64 (7): 721–752. doi:10.1130/0016-7606(1953)64[721:cole]2.0.co;2.
- ^ Page Module:Citation/CS1/styles.css has no content."Pediplain". Encyclopædia Britannica.
- ^ Page Module:Citation/CS1/styles.css has no content.Fairbridge, Rhodes W.; Finkl Jr., Charles W. (1980). "Cratonic erosion unconformities and peneplains". The Journal of Geology. 88 (1): 69–86. Bibcode:1980JG.....88...69F. doi:10.1086/628474.
- ^ Page Module:Citation/CS1/styles.css has no content.Muñoz-Farías, Sebastián; Ritter, Benedikt; Dunai, Tibor J.; Morales-Leal, Jorge; Campos, Eduardo; Spikings, Richard; Riquelme, Rodrigo (2023). "Geomorphological significance of the Atacama Pediplain as a marker for the climatic and tectonic evolution of the Andean forearc, between 26° to 28°S". Geomorphology. 420. Bibcode:2023Geomo.42008504M. doi:10.1016/j.geomorph.2022.108504.
- ^ Page Module:Citation/CS1/styles.css has no content.Fölster, Horst (1964). "Morphogenese der südsudanischen Pediplane". Zeitschrift für Geomorphologie (in German). 8 (4): 393–423.
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