Micro-Morphology of the Snow Surface at the Quelccaya Ice Cap, Peru

Abstract During the June-July 1979 expedition a large variety of micro-forms was observed at the surface of the Quelccaya ice cap, their altitudinal distribution being primarily controlled by the heat budget. At 5200–5300 m penitentes are best developed, with azimuth orientation and inclination of f...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Hastenrath, Stefan, Koci, Bruce
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1981
Subjects:
Online Access:http://dx.doi.org/10.1017/s002214300001145x
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300001145X
Description
Summary:Abstract During the June-July 1979 expedition a large variety of micro-forms was observed at the surface of the Quelccaya ice cap, their altitudinal distribution being primarily controlled by the heat budget. At 5200–5300 m penitentes are best developed, with azimuth orientation and inclination of features conforming to the insolation geometry around local noon. At a westward-facing slope in 5360–5380 m a set of penitentes striking parallel to the contours is superimposed on the pattern dominating at the lower elevations. The ablation forms of penitentes give way to various deposition features above a transition zone around 5400 m in broad agreement with the larger net all-wave radiation and greater importance of melting at lower elevations. The succession of forms with an upward change from surface-parallel plates to elaborate dendritic forms appears to be controlled by the temperature conditions. The conspicuous development of forms encountered during the 1979 expedition appears characteristic of prolonged absence of fresh snow-fall subsequent to a season with abundant precipitation.