Ice‐wedge rejuvenation, fosheim peninsula, ellesmere Island, Canada

• Published in: Permafrost and Periglacial Processes
• Main Author: Lewkowicz, Antoni G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1994
• Subjects: Canada; Ellesmere Island; Eureka; Fosheim Peninsula; Permafrost and Periglacial Processes
• Online Access: http://dx.doi.org/10.1002/ppp.3430050405; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.3430050405; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.3430050405

Abstract Ice wedges with multiple growth stages and complex wedge systems are described for six sites on the Fosheim Peninsula. Recent rates of lateral wedge growth, inferred from tritium concentrations within the ice, are 2–5 mm a −1 . One factor responsible for ice wedge rejuvenation in this area is colluviation on low‐angled slope segments by slopewash, solifluction and active‐layer detachment processes or by mudflow within retrogressive thaw slumps. The most complex section examined was at the base of a long slope where colluvial deposits overlay peat. Epigenetic and syngenetic wedges of at least two and possibly three different ages were present as a result of sedimentation rates estimated to be 4–25 mm a −1 . The second factor producing wedge rejuvenation is variability in summer climate, and this is responsible for the development of the uppermost growth stages at all actively cracking sites. The deepest thaws in the past 45 years were hind‐cast for 1960 and 1962 so that more than 25 years of aggradation had taken place by the time of fieldwork. More generally, it can be shown that there is a significant probability that secondary wedges will be present during any period without regional climatic change. For the Eureka summer climate, the probability is 0.2 that a secondary wedge at least 5 cm high and 10 years old will be observed at any randomly exposed section. Thus field observation of widespread secondary growth stages is not necessarily an indication of recent climatic change but may be due to normal climatic variability.