Robinson, S.C., 2007, Late Pleistocene - early Holocene plant microfossils and pollen from the Yukon Flats, central Alaska: Edmonton, Alberta, Canada, University of Alberta, M.Sc. thesis, 98 p.
Dramatic climate changes and expansion of new biomes characterize the late Pleistocene - early Holocene of eastern Beringia. Analysis of plant macrofossils and pollen from three different sites in the Yukon Flats, central Alaska, record the past vegetation during the late Pleistocene - early Holocene (ca. 11,500-6,900 14C yrs BP) transition. The first paper deals with plant macrofossils associated with one of the earliest post-glacial beaver dams (ca. 9,300 14C yrs BP) found in central Alaska. Vegetation reconstruction suggests a warmer-than-modern climate during the early Holocene. The second paper examines eight paleosols and their associated plant macrofossils and pollen in eolian deposits at two sites ranging from 11,500-6,900 14C yrs BP in the Yukon Flats. Spruce macrofossils were found in a paleosol dated at 10,700 14C yrs BP. High spruce pollen percentages (26%) were also recorded near the paleosol. This is the earliest post-LGM evidence for spruce in Alaska. Comparison with other post-glacial spruce records in Alaska, Yukon Territory, and the Northwest Territories suggests a spruce refugium during the late Wisconsinan glaciation, perhaps in northwestern Canada.
Theses and Dissertations