“In explaining the concept of ‘Pediplanation’, King combined the ideas of Davis, Penck and Wood with his own.” Elaborate.

Q. “In explaining the concept of ‘Pediplanation’, King combined the ideas of Davis, Penck and Wood with his own.” Elaborate.

Pediplanation is Lester Charles King’s model of landscape reduction by parallel scarp retreat and the lateral coalescence of pediments into a pediplain. Its interest lies in its parentage. King borrowed his architecture from Davis, his slope mechanism from Penck and his slope vocabulary from Wood, then fused them with a claim none of the three had made — that scarp retreat is the master process of landscape reduction everywhere. The borrowings can be apportioned precisely.

What King Took From Davis: The Cyclic Frame

• The cycle itself. King kept the Davisian architecture of a directional sequence initiated by uplift running to a low-relief end-form, and Davis’s own vocabulary of youth, maturity and old age for its stages.
• The tectonic assumption. Like Davis, King begins each cycle with rapid uplift followed by long crustal stability — not Penck’s continuous, accelerating upheaval. On this decisive point King is closer to Davis than to Penck.
• An end-surface as the goal. Denudation still drives towards a definable end-form; King simply replaced the peneplain with the pediplain.
• The interrupted cycle. Davis’s rejuvenation becomes King’s polycyclic staircase, successive uplifts leaving older pediplain remnants preserved on summits — King’s antique pediplanation.
• What King discarded was the process content — Davis’s slope decline and downwasting under a humid-temperate “normal” regime.

What King Took From Penck: Parallel Retreat and the Uplift–Denudation Ratio

• Parallel slope retreat. Penck had already argued that slopes need not flatten with time but may retreat backwards while holding their angle, the steep Böschung wasting back above an expanding Haldenhang. King made this the engine of his scarp: “there is no reduction in their steepness when they are wasted back by weathering or rain wash.”
• The endogenetic–exogenetic ratio. From Penck came the principle that landform expresses the ratio of the rate of uplift to the rate of denudation rather than elapsed time — the reasoning behind King’s insistence that scarp form is process-determined, not age-determined.
• The stepped end-landscape. Penck’s Piedmonttreppen — benches cut successively at the retreating margin of an uplifted mass — is the direct ancestor of King’s headward-growing succession of intersecting pediplains, each new scarp initiated at the far edge of the last surface.
• A caution worth registering. The Penck that King inherited was partly a mistranslation: early English renderings of Die morphologische Analyse (1924; translated 1953) made Penck a theorist of parallel retreat, while later readings show he argued for slope replacement, each upper unit replaced by a gentler one from below. King borrowed a simplified Penck — which explains why his parallel retreat is more absolute than anything in the German original.

What King Took From Wood: The Four-Unit Slope

• Alan Wood (1942) — not, as is often miswritten, McGee — identified the four recurring elements of a fully developed hillslope profile, and King took the scheme over almost wholesale.
  • Waxing slope — the convex summital crest, formed by soil creep and weathering.
  • Free face — the bare rock scarp, kept clear of debris by rockfall, landslide and gullying; the most active element of the profile.
  • Debris or constant slope — the rectilinear talus below, standing at the angle of repose of its material.
  • Waning slope or pediment — the basal concavity cut by turbulent sheet flood across solid rock.
• King’s modification was to universalise it. Wood described a slope form; King asserted that all four elements develop in all regions and all climates wherever there is sufficient relief and fluvial denudation dominates.
• Semi-independent evolution. King added that the four units evolve partly independently while remaining coupled, so where bedrock is weak or relief slight the free face and debris slope vanish first, leaving a decadent convexo-concave hillslope.

What Was King’s Own

• Scarp retreat as the master process. King’s central original claim is that backwearing, not downwearing, reduces landscapes, and that this holds under most climates, not merely in deserts — an inversion of Davis’s hierarchy of processes, not an amendment to it.
• The pediment as the fundamental landform. King’s southern African landscape resolved into three elements: rock pediments of 1.5° to 7° cut across solid rock, bounding scarps of 15° to 30° retreating by backwasting, and residual inselbergs, whose rounded forms are bornhardts and castle koppies.
• Coalescence into pediplains. As scarps retreat, adjacent pediments widen and merge into the “multi-concave” pediplain — an end-form distinct from both Davis’s convexo-concave peneplain and Penck’s Endrumpf.
• The pediplanation cycle (proposed 1948; systematised in “Canons of landscape evolution”, 1953, and The Morphology of the Earth, 1962), driven by the twin processes of pedimentation and scarp retreat.
  • Youth — uplift of a pre-existing pediplain; rapid incision, gorges, knickpoints migrating upstream; small pediments appear at valley bottoms; relief at its maximum.
  • Maturity — downcutting slackens, lateral planation dominates, pediments of 5° to 10° widen and begin to coalesce, interfluves shrink to inselbergs.
  • Old age — pediments merge into an extensive pediplain carrying a few surviving inselbergs; unlike a peneplain it continues to grow headward as a fresh scarp consumes the surface behind it.
• Semi-arid as the normal case. King reversed Davis’s baseline, treating the savanna and semi-arid landscape as the geomorphic norm and the humid-temperate case as the special one.
• Gondwana-wide correlation. King used his surfaces as global stratigraphic markers, matching the Jurassic Gondwana pediplain of Africa at about 1300 m with Brazilian counterparts at 700–1000 m, and the Cretaceous African surface with an Australian equivalent — an argument that presupposes continental drift and dates the highest remnants to before Gondwana break-up.

Source	What King took	What King changed
Davis (1899)	Cyclic frame; youth–maturity–old age; uplift then stability; an end-surface; the interrupted cycle	Replaced slope decline with backwearing, and the peneplain with the pediplain
Penck (1924)	Parallel retreat of the scarp; the uplift–denudation ratio; the Piedmonttreppen staircase	Simplified a partly mistranslated Penck; restored Davisian episodic uplift
Wood (1942)	The four-unit slope: waxing slope, free face, debris slope, pediment	Made it universal across climates and allowed semi-independent evolution of units
King’s own	—	Scarp retreat as master process; pediment as fundamental landform; pediplain by coalescence; Gondwana correlation

Pediplain Against Peneplain

Aspect	Pediplain (King)	Peneplain (Davis)
Dominant process	Backwearing by scarp retreat	Downwearing by vertical denudation
Slope behaviour	Parallel retreat at constant angle	Progressive slope decline
Normal climate	Semi-arid and savanna	Humid temperate
Surface form	Multi-concave, coalesced pediments, inselbergs	Smoothly convexo-concave, monadnocks
After completion	Grows headward as a new scarp retreats	Static until re-uplifted

Field Anchors

• The Great Escarpment of southern Africa is King’s own ground and his strongest case: a continuous, steep, retreating scarp separating a high interior pediplain from lower coastal surfaces — the model written across a subcontinent.
• India’s Western Ghats escarpment is routinely read in King’s terms, as a scarp retreating eastwards from a rifted margin while pediments extend at its foot in the Konkan.
• The Peninsular and Deccan erosion surfaces are the Indian test case — K.R. Dikshit’s work (1970) on polycyclic reliefs of the Deccan trap, the accordant patlands of the Ranchi plateau, and the Kaimur, Panna and Rewa surfaces of the Belan basin. The debate turns on whether these are pediplain remnants at all, since the Deccan’s horizontal trap flows of unequal resistance yield step-topography by differential erosion alone.
• Inselbergs and monadnocks in the Nilgiris, on the Bundelkhand granite upland and among the Aravalli residuals give King’s residual-hill category real Indian instances.

Critique and Modern Standing

• Universalism is the central charge. The model was built from southern African evidence and then exported; the claim that landform development is uniform across environments, and climatic change geomorphically insignificant, is its weakest plank.
• The humid tropics escaped him. Deep weathering and stripping — the etchplanation of Wayland (1934) and Büdel (1957) — explains many tropical surfaces better than sheet-flood pedimentation, and pediments are now often attributed to structure, weathering-front geometry and tectonics rather than lateral planation alone.
• The surfaces cannot be dated. Antique pediplanation rests on altimetric correlation across continents over immense spans, with warping, tilting and burial destroying the correspondence; the chronology is inferential.
• Timing worked against it. The “Canons” appeared in 1953, as geomorphology turned to instrumented measurement at short timescales; King’s qualitative, continental-scale reasoning found few takers.
• Hack (1960) supplied the alternative. Working in the Appalachians and the Shenandoah Valley, Hack argued for dynamic equilibrium in an open system, with form reflecting the balance between rock resistance and process intensity — dispensing with end-forms altogether and so denying the very target towards which both peneplanation and pediplanation are directed.

Conclusion

The verdict in the quotation is exact and should be defended, not merely repeated. King’s achievement was integrative rather than inventive: Davis gave him the cycle, Penck the retreating slope, Wood the anatomy of that slope, and King supplied the argument that binds them — that backwearing, not downwearing, is how the Earth’s surfaces are made. That argument was over-generalised from one continent and remains hard to date, yet the pediment and the pediplain survive as working categories, and no later model has replaced scarp retreat as the explanation of a great escarpment.