3 Geomorphic Cycles of Slope Development-Davis, Penck and King YouTube Lecture Handouts
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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
| Cycle | Youth | Old | Maturity |
| Cycle of Drainage Development | Major Rivers | Rivers with Floods | Flood Plains |
| Cycle of Slope Development | Convex Slope Vertical Downcut | Lateral Erosion | Flatter Slope |
| Cycle of Landscape Development | V-Shaped Valley | Lateral Development | Low 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 β 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)
| Davis Cycle of Erosion | Penck Cycle of Erosion |
| Erosion starts when upliftment stops | Erosion & upliftment go together; initial stages have rapid upliftment |
| Long crustal stability after initial uplift | Continuous upliftment which stops very late in the cycle |
| Compared to erosion, upliftment happens in very small period | Span of upliftment is more or less same as that of erosion |
| Structure, time & process affect the erosion | Erosion depends on rate of upliftment, & degradation |
| Time dependent | Time independent |
| Start on many different structural units | Starts on convex lowland known as primarrumpf |
| Peniplain is the end product | Endrumpf is the end product |
| Down wasting of slopes | Backwashing of slopes |
| Definite landform sequence | Landform sequence depends on rate & characteristics of upliftment & erosion |
| Backward Looking Theory | Forward Looking Theory |
KingΥs 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) β Convex, More Transportation due to high slope
- Free Face (Scarp) - bedrock outcrop
- Debris Slope (Constant Slope) β retreats with free face
- Waning Slope (Pediment) β Concave, Sheet wash
β Manishika