Pollen distribution in recent marine sediments, eastern Canada

Abstract

Analysis of 90 samples from coastal and continental shelf areas off eastern Canada between 42 and 69.degree.N shows that Quaternary pollen and spores are present in recent marine muds throughout this region. Pollen and spore concentrations range from 50,000-100 grains/cm3 and they decrease both offshore as a function of distance from vegetation sources and northwards as a function of lower vegetation density north of the summer Arctic Frontal Zone. Isopercentage contours show that maximum relative abundances of most palynomorphs occur in marine sediments adjacent to their regions of highest vegetation representation onshore. However, Pinus and Picea pollen tend to increase in percentage abundance with distance offshore. Presence of these tree pollen in marine sediments off Baffin Island implies that wind transport is an important pathway by which bisaccate pollen types enter the ocean, in addition to fluvial transport. Q-mode factor analysis shows that 4 major factors account for 89% of the variance among the marine palynomorph samples, while 2 other factors (6% of the variance) apparently reflect selective transport of Pinus pollen or local over-representation of Gramineae. The major factor assemblages are as follows: boreal forest assemblage, with high weightings of Picea and maximum loading adjacent to the boreal forest, 48-54.degree.N; arctic assemblage, weighted by Rosaceae, Gramineae and Cyperaceae, with maximum loadings off Baffin Island, 60-69.degree.N; mixed forest assemblage, weighted by Betula tree pollen, Picea glauca, Pinus strobus, Tsuga and temperate trees (e.g., Quercus, Acer), with maximum loadings in the southeast, 42-48.degree.N; subarctic assemblage, with high weightings of Sphagnum, Alnus and Lycopodium, and maximum loadings adjacent to forest-tundra and low arctic tundra, 54-60.degree.N. These regional marine pollen assemblages are empirically related to contemporary climatic parameters, thus indicating the potential value of pollen analysis for direct correlation between Quaternary paleoclimatic records onshore and in marine areas bordering eastern Canada.