Météorisation des Blocs de Granite à la Surface des Pédiments dans le Nord du Yukon, Canada

• Published in: Permafrost and Periglacial Processes
• Main Authors: Bjornson, Jean, Lauriol, Bernard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Canada; Yukon; Old Crow; Permafrost and Periglacial Processes; Alaska
• Online Access: http://dx.doi.org/10.1002/ppp.391; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.391; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.391

Abstract This article describes how tors calve granite boulders which are then distributed in three zones on the surrounding pediments. The boulders are broken down to granules, sand, silt and clay on the surface of the pediments. The study site is located on a rounded hill of the Old Crow batholith near the Yukon‐Alaska border. The methods and techniques used were grain size analysis, rock and sediment geochemistry and boulder fabric. Results show that boulders become smaller and less frequent on the pediment as distance from the tor increases. Weathering processes disaggregate the boulders before they reach the talwegs. Chronological evaluation suggests that 10s to 100s ka are necessary for weathering to reduce the boulders to fine particles. Copyright © 2001 John Wiley & Sons, Ltd.