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]
View of a scarpment and pediment in Namibia. The somewhat flat area in the foreground is an incipient pediplain.
Cattle on an Oudalan pediplain, between Gorom and Oursi, Burkina Faso.
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]
^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
^ abJones, David K.C. (2004). "Denudation chronology". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. pp. 244–248.
^ abcMigoń, Piotr (2004). "Planation surface". In Goudie, A.S. (ed.). Encyclopedia of Geomorphology. pp. 788–792.
^ abTwidale, 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.
^ abcKing, 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.
pediplain, geology, geomorphology, pediplain, from, latin, genitive, case, pedis, meaning, foot, extensive, plain, formed, coalescence, pediments, processes, through, which, pediplains, forms, known, pediplanation, concepts, pediplain, pediplanation, were, fir. 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 View of a scarpment and pediment in Namibia The somewhat flat area in the foreground is an incipient pediplain Cattle on an Oudalan pediplain between Gorom and Oursi Burkina Faso 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 Contents 1 Examples 2 See also 3 Notes 4 ReferencesExamples EditSouth Sudan 7 See also EditErosion surface Natural surface created by rock erosion Etchplain Plain where the bedrock has been subject to considerable subsurface weathering Paleosurface Surface made by erosion of considerable antiquity Planation surface Large scale surface that is almost flatNotes Edit 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 Edit a b Jones David K C 2004 Denudation chronology In Goudie A S ed Encyclopedia of Geomorphology pp 244 248 a b c Migon Piotr 2004 Planation surface In Goudie A S ed Encyclopedia of Geomorphology pp 788 792 a b 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 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 Pediplain Encyclopaedia Britannica 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 Folster Horst 1964 Morphogenese der sudsudanischen Pediplane Zeitschrift fur Geomorphologie in German 8 4 393 423 This article about geography terminology is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Pediplain amp oldid 1143442712, wikipedia, wiki, book, books, library,
