In the tidally influenced Fraser River and adjacent Strait of Georgia (SoG), Canada, palynological and carbon isotope (δ13Corg) signatures of channel-margin sediments are compared to environmental parameters (e.g., substrate grain size, water salinity) in order to establish how these vary across the tidal-fluvial transition. Palynological assemblages in both the Fraser River and SoG (delta front and prodelta) are dominated by tree pollen, which comprises between 85% and 95% of all assemblages. Relative abundances of marine dinocysts are markedly low, and the maximum abundance of dinocysts is 6.8% or 1,023 cysts g-1 of sediment in samples recovered from the prodelta. Dinocyst abundances do not exceed 2% of the total palynological assemblage in the Fraser River, and the number and diversity of dinocysts gradually decreases landward. Organic carbon-13 enrichment values range from -26.55‰ in sediments deposited in the freshwater-tidal reach of the Fraser River, to -21.08‰ in prodeltaic sediments. The δ13Corg and palynological signatures of river, delta front, and prodelta sediments indicate a dominance of terrestrially sourced organic matter regardless of brackish-water and tidal influence on sediment deposition.
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