Answers are grounded in this paper and cite their sources.
Analyses of lignin oxidation products and pollen for an 11-meter core from Lake Washington provide independent but similar reconstructions of the late Quaternary vegetation in the Puget Lowland. An exception is in sediments of the late Pleistocene where pollen percentages and influx values suggest conifer forest whereas lignin compositions suggest a treeless source region. This dissimilarity appears to result from different major provenances: eolian transport of pollen to the lake from adjacent or downstream drainage basins as opposed to fluvial transport of lignified plant debris only from the Lake Washington drainage basin.
No takes yet. Share an insight, caveat, or question.
Leopold et al. (1982) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: