Late Quaternary climatic and glacial history of the west-central Yukon Territory, Canada

Investigation of two areas in the west-central Yukon Territory, Canada suggests that previous glacial and paleoclimatic chronologies require reinterpretation. Both lakes were selected because they lie in terrain previously assumed to have remained unglaciated during the last ice age, yet both appear to have anomalously young basal ages. Cores from Chapman Lake, and geomorphic mapping of the Reid age (Illinoian) moraine in which it lies suggest that the age of the moraine is in fact much younger, and that it was likely deposited during the last ice age (McConnell). Radiocarbon dating and correlations between the Chapman and Gravel Lake organic matter records and the GISP2 ice core suggest that climate following the deposition of this moraine was highly variable, with two cold periods during the Late Glacial correlating to the Older and Younger Dryas. Paleoclimatic reconstructions at Chapman Lake suggest, in contrast to previous work, that the Holocene climate of the Yukon was also highly variable, with intervals corresponding to the Neoglacial, Medieval Warm Period and Little Ice Age recorded in organic matter, grain size and macrofossil data.; These data provide important new insight into the glacial chronology and post-glacial climate of the Yukon and suggest that hemispheric and global changes in climate documented from locations elsewhere in North America and Europe also affected the Yukon. This suggests that post-glacial climate across the Northern Hemisphere was actually very uniform and that a persistent atmospheric teleconnection between the Atlantic and Pacific regions existed through the Late Glacial and into the Holocene.*; *This dissertation includes a CD that is compound (contains both a paper copy and a CD as part of the dissertation). The CD requires the following applications: Windows 95/98; Adobe Acrobat; Microsoft Office; Internet browser; Imaging Preview.