Early Holocene glacier advance in the North Cascade Range, Washington

Abstract

Moraines and glacial drift of the White Chuck advance were deposited in early Holocene time in cirques near Glacier Peak, Washington. These sediments overlie Glacier Peak tephra, including layers G, N, F, C, M, T, and B, which were erupted between about 12,500 and 11,250 yr B.P. White Chuck drift is overlain by Mazama tephra layer O, deposited about 6,700 yr B.P. Charcoal collected from till deposited during the White Chuck advance is about 8,300 to 8,400 radiocarbon years old, indicating that the glacial advance that deposited the till occurred about this time and that a previously unrecognized period of cooling and/or increased precipitation of sufficient intensity to produce glacial advances comparable to or greater than those of the recent Little Ice Age occurred in early Holocene time in the North Cascade Range. Other pre-Altithermal moraines from the Cascades, the Rocky Mountains, Laurentide Canada, and Baffin Island may have been produced during this cool period.