Palynology and Phytogeographical Significance of a Late-Pleistocene Refugium Near Kalaloch, Washington

Abstract

A sea cliff facing the open ocean 3 km north of Kalaloch, Washington, and exposing 32 m of interbedded peat, clay, sand, and gravel contains a unique continuous record of late-Pleistocene vegetation and environments on the western side of the Olympic Peninsula. The record obtains from the palynology of plant communities in the unglaciated refugium. Fourteen radiocarbon dates from peat beds in the sea cliff reveal that the record spans the time from 16,700 B. P. to greater than 47,000 B. P. The earliest organic deposits are estimated to date from 70,000 B. P. Pollen assemblages from 222 sample levels in a measured section, divided into 16 zones, are correlated, in the main, with the sequence of Salmon springs, Olympia, and Fraser geologic-climatic units in the Puget Lowland. Correlation derives from the fluctuations of a July average temperature curve reconstructed from the modern vegetation and climatic equivalents of the pollen assemblages. The sequence of stadial and interstadial environments depicted at Kalaloch is found to be more complex than is indicated by the Puget Lowland succession.