A 14,000 yr paleoenvironmental record from Windmill Lake, Central Alaska: Lateglacial and Holocene vegetation in the Alaska range

Abstract

A 14,000 yr high-resolution pollen and lake-level record from Windmill Lake in central Alaska provides new evidence for the Late Pleistocene and Holocene paleoenvironments of this region. At 14,000 14C yr BP, sparse herb tundra and low lake-levels indicate a cold, arid environment. About 11,800 14C yr BP, the vegetation abruptly shifted to a shrub tundra and lake-levels increased, suggesting warmer and more mesic conditions. Ca 10,500–10,200 14C yr BP, herbaceous taxa increased at the expense of the shrubs, suggesting a transient episode of climatic deterioration nearly contemporaneous with the Younger Dryas chronozone. By 8000 14C yr BP, spruce was present in the watershed and alder grew locally by 6500 14C yr BP. The AMS radiocarbon chronology indicates later expansions of Betula, Picea, and Alnus than at most sites in central Alaska, which are conventionally dated.