A note on biological weathering on nunataks of the juneau icefield, Alaska
Observations on a number of nunataks of the Juneau Icefield indicate that chasmolithic algae play a major role in the breakdown of granitic rock. Expansion and contraction of the algal mucilage, caused by wetting and drying episodes, results in the surface flaking of the rock. Available data suggest...
| Published in: | Permafrost and Periglacial Processes |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/ppp.3430010209 |
| Summary: | Observations on a number of nunataks of the Juneau Icefield indicate that chasmolithic algae play a major role in the breakdown of granitic rock. Expansion and contraction of the algal mucilage, caused by wetting and drying episodes, results in the surface flaking of the rock. Available data suggest that the average mass of material lost per year from 1 m2 of rock could be as high as 562 g. It is suggested that biological weathering may be a major destructive mechanism of the granitic lithologies. Des observations sur plusieurs nunataks du glacier Juneau indiquent que des algues chasmolithiques jouent un rǒle capital dans la rupture des roches granitiques. L'expansion et la contraction du mucilage algaire, dues à des périodes de sécheresse et d'humidité entraìnet la détachement de plaques superficielles de roche. Les données disponibles suggèrent que la masse de matériau perdue par an sur une surface de 1 m2 de roche peut atteindre une valeur aussi élevée que 562 g. Il est suggéré que cette altération biologique peut ětre un mécanisme de désagrégation capital pour des roches granitiques. |
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