Stratigraphy of a Silt-cored Palsa, Atlin Region, British Columbia, Canada

• Published in: ARCTIC
• Main Author: Seppälä, Matti
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Arctic Institute of North America 1980
• Subjects: Cores; Drilling; Ground ice; Palsas; Palynology; Radiocarbon dating; Sedimentation; Atlin Lake region; British Columbia/Yukon; Atlin; Atlin Lake; British Columbia; Canada; Yukon; Arctic; Ice; palsa; palsas; permafrost
• Online Access: https://journalhosting.ucalgary.ca/index.php/arctic/article/view/65621

Palsas in the Fourth of July Creek valley, B.C., Canada are round- or oval-shaped single hummocks with cores of silty permafrost. Their height ranges from 0.5 to 3 m. The top layer of the studied palsa is only 7 cm peat. In the frozen silt core are found segregated ice lenses up to 15 cm thick. The 0.006-0.02 mm size fraction of the core material of the palsa constitutes 55%. Carbon fourteen datings of the organic material of two different layers in the core of the palsa gave 7470 ± 180 and 7990 ± 180 years B.P. Special attention is given to the unusual sequence of dates obtained and to the pollen stratigraphy. The material is explained by redeposition by flood water into a pond and later uplifting by frost. No evidence of mixing of the original bottom sediments is found.