Postglacial vegetational change and soil development in southeastern Labrador as inferred from pollen and chemical stratigraphy.

Palynological and geochemical analyses of Holocene lake sediments are used to evaluate long-term interactions between vegetation and soils from 4 sites in SE Labrador, Canada. Early Holocene lake muds deposited under tundra vegetation are predominantly inorganic and contain high concentrations of allogenic clastics derived from the erosion of barren soils. Concentrations of humic materials and redox - pH-sensitive elements (Fe, Mn, P, Al) of authigenic origin increace markedly with the subsequent invasion of spruce and fir (8000-7000yr BP). This transition of inorganic tundra inceptisols to humic-rich boreal spodosols contributed to the competitive replacement of Picea glauca and Abies balsamea by the more edaphically tolerat P. mariana between 6500-6000yr BP. A subsequent decline in sedimentary humic content and increase in allogenic components may signal a regional climatic cooling after 4000yr BP. Geochemical analyses of lake sediments reveal no stratigraphic changes in allogenic mineral composition that might indicate progressive soil weathering.-from Authors