Long continental pollen sequence from Washington State (U.S.A.): correlation of upper levels with marine pollen-oxygen isotope stratigraphy through substage 5e

Abstract

Fossil pollen from a 7.70-m core and a pit excavated 2.20 m deep in a mire at Humptulips, located on glacial drift of the Olympic Peninsula in western Washington State, presents a continuous record of vegetation since the Middle Pleistocene. Chronostratigraphic relations, established from sedimentation rates based on finite and infinite radiocarbon dates in the upper 2 m of the deposit, cover the last glacial cycle, Illinoian glaciation, and apparently older millennia. The pollen stratigraphy, contained in 16 pollen assemblage zones, shows a sequence of vegetation types including tundra, park tundra, woodland, and closed confierous forest. Comparison with pollen and oxygen isotope stratigraphy of marine core Y72 11 1 from the Pacific Ocean off Oregon establishes direct continental-marine correlation of upper levels at Humptulips through substage 5e.