Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

The Holocene chronology of gelifluction events in a snow‐patch environment of the Richmond Gulf area, eastern Hudson Bay Coast (northern Québec), has been constructed using sixty radiocarbon‐dated buried organic horizons. The samples were recovered from nine soil trenches located along an altitudinal gradient associated with a chronosequence as determined by the regional land emersion curve. The most significant gelifluction activity occurred after c. 2,800 B. P. Gelifluction events occurred around 5,600, 5,000, 4,500, 3,150, 2,500, 1,550, 1,200 and 450 B.P., and at present. According to the frequency of 14C dates. gelifluction has been particularly active between 2,800‐2,300, 1,700–900 and 600‐300 B.P., and at present. Gelifluction occurrence seems to be closely related to well‐bracketed cold episodes in northern Québec. The increase in frequency of 14C dates associated with burial of organic matter through gelifluction after c. 2,800 B. P. substantiates the colling trend depicted elsewhere, both in northern Québec and in the northern hemisphere.