Abstract

A rich sedimentary deposit reaches a depth of more than 4 m in a cave located on the Eardley Escarpment in the Gatineau Park. Analysis shows that the infilling started during the last Ice Age. Following the deglaciation and the Champlain Sea retreat, terrestrial sedimentation began. Radiocarbon dating of wood charcoal indicates that around 9200 ± 110 years BP trees and shrubs were starting to grow on the Eardley Escarpment. A fauna, with boreal affinity, including the Ungava collared lemming (Dicrostonyx hudsonius), was living in vegetation dominated by jack pine. After 8170 ± 60 years BP, the boreal forest was replaced by a mixed forest dominated by white pine, oak, and red maple. The faunal assemblage was enriched at that time by woodland vole (Microtus pinetorum) and Strobilops aenea, a terrestrial mollusk. These two species are presently living in the Carolinian Life Zone south of the Great Lakes. By around 5742 ± 120 years BP these two species had left the site, and the modern fauna was established with mammals, such as the black bear and the white-tailed deer. Holocene infilling of the cave was gravity driven and unassisted, except for an episode just before 8170 ± 60 years BP when a sand layer was deposited by water coming from the surface.

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