3 Geomorphic Cycles of Slope Development - Davis, Penck and King YouTube Lecture Handouts

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3 Geomorphic Cycles of Slope Development - Davis, Penck and King

Major Theories

  • Peneplanation or Slope Decline theory of W. M. Davis
  • Pendiplanation or Slope Replacement Theory of W. Penck
  • Pedimentation or Parallel Retreat Theory of L. C. King

DAVIS

Erosion only after upliftment is completed

Trio of Davis

Illustration: Trio of Davis
Illustration: Trio of Davis
Table of Cycle of DavisTable of Cycle of Davis
CycleYouthOldMaturity
Cycle of Drainage DevelopmentMajor RiversRivers with FloodsFlood Plains
Cycle of Slope DevelopmentConvex Slope

Vertical Downcut

Lateral ErosionFlatter Slope
Cycle of Landscape DevelopmentV-Shaped ValleyLateral DevelopmentLow Surface & Low Gradient

Strengths & Weaknesses of Davis Model

Revolutionary Ideas by Davis

  • Landscape development
  • Development of slope
  • Development of river & drainage profiles
  • Effects of rock type on different stages
  • Integrating the effect of climatic accidents on denudation forces

PENCK

  • Shape of landforms is function of ratio of velocity of endogenous movement to intensity of erosion

Premises by Penck

  • Surface is result of competition b/w endogenetic and exogenetic forces
  • Shape & Intensity depend on rate of incision & removal of debris
  • Explain tectonic movement and cause – By crust information
  • Upliftment & erosion are co-existent

Stages by Penck

Waxing Or Accelerating Stage (Aufsteigende)

Uniform Development Stage (Gleichformige)

Waning Or Development Stage (Absteigende)

Table of Davis Cycle of Erosion and Penk Cycle of ErosionTable of Davis Cycle of Erosion and Penk Cycle of Erosion
Davis Cycle of ErosionPenck Cycle of Erosion
Erosion starts when upliftment stopsErosion & upliftment go together; initial stages have rapid upliftment
Long crustal stability after initial upliftContinuous upliftment which stops very late in the cycle
Compared to erosion, upliftment happens in very small periodSpan of upliftment is more or less same as that of erosion
Structure, time & process affect the erosionErosion depends on rate of upliftment, & degradation
Time dependentTime independent
Start on many different structural unitsStarts on convex lowland known as primarrumpf
Peniplain is the end productEndrumpf is the end product
Down wasting of slopesBackwashing of slopes
Definite landform sequenceLandform sequence depends on rate & characteristics of upliftment & erosion
Backward Looking TheoryForward Looking Theory

King՚s Theory

  • Parallel retreat of scarps
  • Resulting constraint on down wearing of scarp surface
  • Uplift due to denudational unloading

Slope Profile by King

  • Waxing Slope (Crest) – Convex, More Transportation due to high slope
  • Free Face (Scarp) - bedrock outcrop
  • Debris Slope (Constant Slope) – retreats with free face
  • Waning Slope (Pediment) – Concave, Sheet wash
Illustration: Slope Profile by King

✍ Manishika