LATE HOLOCENE VEGETATION CHANGES FROM A LAKE WITH VARVED SEDIMENTS FROM THE GATINEAU REGION OF QUéBEC

A sediment core from Lac Brûlé (45°43'09" N, 75°26'32"O 270m), in western Québec contained varved sediments which provide the basis for a high-resolution analysis of the late Holocene climate and vegetation of the region. Lac Brûlé is 43 m deep, and the deepest sediments showed a clear succession of alternating brown and black layers; a radiocarbon date confirms the laminations are varves. Variability of several timescales are evident in the varve thickness data, in particular a major change in varve thickness at 650 years ago. Pollen analysis from core provides a 1400-year record of vegetation change. Abundant taxa in the sediments include Pinus, Betula, Picea, Quercus, Abies and Tsuga.