Central Canadian palynology and its relevance to northwestern Europe in the late quaternary period

Abstract

Analyses of fossil pollen grains and macroscopic plant remains have been made of peat from Keewatin and Manitoba in central Canada, at sites in the tundra and at the northern edge of the Boreal forest. Organic accumulation began immediately after very rapid deglaciation of the region between 8,000 and 6,500 years ago, when Picea forest swiftly colonised the bare ground. There is no evidence for establishment of tundra vegetation after the ice retreat. There is evidence from pollen analysis, plant macrofossils and fossil soils that the forest extended north of its present range by about 300 km from 6,000 to 3,500 years B.P. Movements of the forest limit have been interpreted as reflecting climatic change, and in particular the latitudinal movement of the Arctic airmass in summer (which is considered to determine the northern limit of tree growth in central Canada). Several radiocarbon determinations which have been made of the age of significant horizons in the pollen diagrams show that the inferred climatic changes were synchronous with those experienced by northwestern Europe during the last 6,000 years. The changes in this area also seem to have paralleled those of northern Europe, and this is explained by analogy with the modern pattern of Northern Hemispheric general circulation. Because of the global nature of circulation patterns it is to be expected that the timing of climatic changes should be the same throughout the world, but not that the change should be in the same direction in all regions. The synchroneity and parallelism mentioned above make it worthwhile to employ palynological evidence from central Canada (relatively undisturbed by human activity) to investigate climatic changes in northern Europe, where the fossil-pollen record for the past 5,000 years has been affected by anthropogenic factors.