Premium
Expérience de laboratoire sur la mobilisation par cryoreptation d'un dépôt de pente schisteux, grossier et hétérométrique
Author(s) -
Calmels Fabrice,
Coutard JeanPierre
Publication year - 2000
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/1099-1530(200007/09)11:3<207::aid-ppp351>3.0.co;2-h
Subject(s) - geology , humanities , geomorphology , forestry , art , geography
Head deposits are generally assumed to have accumulated by frost creep and gelifluction processes. The aim of the laboratory experiment related here was to verify these hypothesis. The schistous material used was taken from a natural slope of the Massif Armoricain (Lower Normandy). The 25° gradient of the experimental slope corresponds to that typical of the zones producing head material at many sites in Normandy. After 18 freeze–thaw cycles, the mean value of the surface displacement measured ranged between 0.5 and 3.7 cm per cycle. All the mass of the material was deformed by frost creep. Mean per cycle flow of material accumulated at the bottom of the slope was 0.43 cm 3 cm −1 . At the surface, the fabric of the more elongated fragments was modified; the a ‐axis of one‐third of elongate fragments became oriented parallel to the maximum slope direction. Copyright © 2000 John Wiley & Sons, Ltd.