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EROSION OR PLANATION SURFACES


Published on: 12/15/2020 4:37:04 AM

Planation surface sometimes called erosion surfaces, have been widely used in geomorphology as indicators of the various stages in the evolution of individual landscapes. The term is applied to areas of land which are flat or have a very low relief, and which are believed to be the end product of long periods of erosion.

Types of Erosion Surfaces

There are six types of Erosion or Planation Surfaces which are given below:

1. Peneplain/ Peneplane

  • End Product of Davisian cycle
  • Product of Temperate & Humid Climate
  • Product of Slope decline & down wasting of Materials
  • It is a lowland of faint relief with convexo-concave profile
  • This plain could only change very slowly, since potential energy for fluvial action was greatly reduced.
  • They represent rivers profile of equilibrium.

2. Pediplain

  • End Product of Arid/ Semi-Arid or savanna cycle of erosion.
  • Concept of L.C King
  • Product of Pediplanation
  • Product of Parallel retreat and down wasting
  • An extensive erosion surface of low relief with steep-sided residual hills that has been formed. by the coalescence of several pediments.

3. Panplain

  • End Product of crickmay's erosion cycle also k/a panplanation cycle
  • Product of parallel retreat, lateral erosion and back wasting.
  • formed by coalescence or joining together of flood-plains.
  • Panplain is much flatter than the peneplain and the residual monadnocks are more steep-sided.

4. Endrumpt

  • Ultimate Landform of Penck's concept of erosion cycle
  • Penck's erosion cycle starts with a low, featureless plain called primarrumpf
  • Product of parallel retreat, slope replacement and backwasting
  • Product of cycle which starts with humid climate and ends in arid climate
  • Residual relief are Barnhardt or inselberg.

5. Etch Plain

  • Where deep weathering occurs on a landscape, a dichotomy is set up b/w the thick regolith of weak, weathered rock and the Underlying zone of intact rock.
  • If subsequent erosion removes the weathered regolith, then a new planation surface develops through exposure of the old weathering front.
  • results in the exposure of structurally defined compartments of resistant rock.
  • characteristic of ancient stable cratonic areas s/a Gondwanaland.

6. Scree Plains

  • Formed by coalescence or joining together of alluvial fans.
  • a collection of broken rock fragments adjacent to maintain slope.
  • result of physical & chemical weathering and erosion acting on a rock face.
  • The Growth of pediments at the expense of the mountain mass result in retreat of the mountain front.

Also Read | PERIGLACIAL CYCLE OF EROSION