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A multivariate analysis of clast displacement rates on stone‐banked sheets, Cordillera Real, Bolivia
Author(s) -
Francou Bernard,
Bertran Pascal
Publication year - 1997
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/(sici)1099-1530(199710/12)8:4<371::aid-ppp263>3.0.co;2-7
Subject(s) - geology , geomorphology , mineralogy , archaeology , geography
Clast movements of stone‐banked sheets were measured for five years at Chacaltaya (5200 m ASL) in the Bolivian Andes (16°S). This environment is characterized by frequent surficial freeze–thaw cycles and high displacement rates, up to 100 cm a −1 on the sheets and 30–40 cm a −1 on the stone banks. Multivariate analysis makes it possible to identify slope gradient, clast size, type of clast substratum (fine‐ or coarse‐grained material) and clast morphology as the main factors controlling the movement. The material in the sheet appears to move faster than the stone bank and the stone banks have a greater velocity than the stone pavement located in the front of them. As a consequence, downslope surfaces are progressively overrun by the banks. This analysis allows quantification of the mechanisms which explain the stratified nature of slope deposits in an Andean periglacial environment. © 1997 John Wiley & Sons, Ltd.