Abstracts
Abstract
A rock labyrinth in the Devonian Palliser Formation, which dips at 24° in the direction 224°, occurs in the Front Ranges of the Rocky Mountains, 5 km northeast of the town of Jasper, Alberta. The area that composes the Rock and Boulder Gardens, 200 m by 500 m in size, is visible on aerial photographs of the Maligne Valley. The labyrinth is distinguished by the regular arrangement of large blocks of carbonates that are separated by widely-gaping joint planes. Kinematic freedom for the translation of these blocks was created when erosion of the south slope allowed blocks to slide out of the hanging Maligne Valley into the Athabasca Valley. The rock labyrinth is believed to have formed under periglacial conditions, driven by the build up of snow in open joints exerting a downslope force on blocks.
Résumé
Dans la Formation dévonienne de Palliser se trouve un labyrinthe rocheux orienté à 224°, dont la pente est de 24° ; il est situé dans les chaînes frontales des montagnes Rocheuses, à 5 km au nord-est de la ville de Jasper, en Alberta. La zone des Rock and Boulder Gardens, qui couvre une superficie de 200 par 500 m, est discernable sur les photographies aériennes de la vallée Maligne. Le labyrinthe se distingue par l’agencement régulier de grands blocs de carbonate séparés par des diaclases béantes. En rendant possible la translation des blocs, l’érosion de la pente sud a permis leur glissement de la vallée suspendue Maligne vers la vallée Athabasca. La formation du labyrinthe rocheux, survenue à la faveur de conditions périglaciaires, aurait été déclenchée par l’accumulation de neige dans les diaclases ouvertes, laquelle aurait exercé sur les blocs une pression vers le bas de la pente.
Appendices
References
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