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

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...

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Bibliographic Details
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
Description
Summary: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.

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