Cryoturbation flats in Wales. A giant variety of garlanded soils
DOI:
https://doi.org/10.26485/BP/1963/12/5Keywords:
cryoturbation, soils, periglacial processes, WalesAbstract
Article in French.
ORIGINAL TITLE: Des replats de cryoturbation au Pays de Galles; une variete geante de sols en guirlandes
In mid-Wales, distinct terrace features have been observed, particularly in the Llanidloes area, Llanfair Caereinion, and the Gerniog, Cledan, Colwyn, and Nodwydd river valleys. These terraces form a stepped pattern on slopes of 2.5°–8°, with convex surfaces 2–15 m high and 50–200 m in diameter. They are composed of poorly sorted material, and the imbrication—perpendicular at the front and parallel within the terrace—indicates mass movement that contributed to their formation. These terraces cannot be the result of agricultural activity or geological structure. They are considered periglacial features, very similar to the Arctic and Alaskan features described by Capps and Taber. Their predominantly easterly exposure suggests formation by nival processes, when westerly winds caused snow to accumulate on the leeward sides of the hills. In a later stage, slow mass movement formed the layered shape of the terraces and the characteristic arrangement of stones.
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