The Holocene development of a debris slope in subarctic Québec, Canada

• Published in: The Holocene
• Main Authors: Marion, Joëlle, Filion, Louise, Hétu, Bernard
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 1995
• Subjects: Canada; permafrost; Subarctic
• Online Access: http://dx.doi.org/10.1177/095968369500500403; https://journals.sagepub.com/doi/pdf/10.1177/095968369500500403

The development of a debris-covered slope in subarctic Québec was reconstructed in relation to vegetation dynamics, fire history and local permafrost evolution. The slope consisted of a low- elevation rockwall and a rockwall-derived debris veneer overlying a sandy till deposit reworked by gelifluction. The sedimentological and stratigraphical data along with radiocarbon dating and den droecological data indicated that: (1) the period around 5050 BP corresponded to the initial establishment of the forest cover probably after paraglacial rockfall activity following deglaciation; (2) it was followed by a period of stability until c. 3200-3000 BP when gelifluction occurred; (3) the period between c. 3000 BP and 900 BP was one of relative stability; until (4) a series of fires after 900 BP initiated a period of destabilization by mass movements and surficial weathering processes; (5) local permafrost formed during the last few centuries, especially under the forest fringe where Sphagnum peat developed. Results from this study indicate a strong connection between fire, slope destabilization and the intensification of geomorphological slope processes during the last millennium at the study site.