Peneplain


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peneplain

[′pēn·ə‚plān]
(geology)

Peneplain

 

a denudation plain that has formed where mountainous regions were leveled under humid conditions. In contrast, there are plains whose initially flat relief was the result of accumulation.

The peneplain concept was introduced into geomorphology in the late 19th century by the American geographer W. M. Davis, who considered the peneplain a theoretically conceivable concluding stage of the geographic cycle. According to Davis, the mechanism of peneplain formation consists in the reduction of every point of the surface of a mountainous region by subaerial erosion, but Davis’ explanation is not universally recognized. L. King disagreed with such an explanation of planation and contrasted the concept of the pediplain to that of the peneplain.

Peneplains are formed at the end of major tectonic cycles during the transition from the orogenic stage of development of the earth’s crust to the platform stage. Thick weathering mantles form within peneplains. When tectonic subsidences occur, peneplains may become buried by sedimentary strata; when uplifts occur, peneplains become raised, as in the case of the syrts of the Tien-Shan.

A. E. KRIVOLUTSKII

References in periodicals archive ?
The final number of samples used was 140 (Marshes: 15; Dunes and Sands: 40; Croplands 12; Peneplains and Slopes: 36; Mountains 37).
The Sardinia Variscan peneplain is locally blanketed by scattered patches of post-Variscan successions that are Carboniferous, Permian and Triassic in age.
These districts lie within the low-lying coastal peneplain.
Plagens characterizes the survey as a professional effort, "leaving the art alone to say what is, at least to me, uplifting in the short run, but then, as I worry about it all, a long, sloping, slight, but discernible peneplain of depression.
The area south and east of Taylorsville is a southeastward-sloping peneplain dissected by a close network of streams.
The area is a gently rolling peneplain above 200-m altitude with a few residual hills up to 350 m.
On the island origin of the endemic trees of the British Guiana peneplain.
It is a 14 km-long ridge with a north-west strike, formed into five distinct hills standing about 200 m above the surrounding peneplain.
Laterite nickel and cobalt mineralization is associated with a peneplain surface developed on the ultramafics.
It is a distinct west-trending lineament for some 13 km created by a narrow (300 to 500 m width), "V'-shaped, 50 to 80 m deep valley incised into a peneplain underlain by the Black Brook Suite (granite and granodiorite) (Fig.
The aspect of peneplain is emphasized by thick loess deposits over 25-30 m.