2014 GSA Annual Meeting in Vancouver, British Columbia (19–22 October 2014)

Paper No. 273-9
Presentation Time: 10:30 AM

FRANKLY SPEAKING: A COMPREHENSIVE RECORD OF HOLOCENE BEHAVIOUR AT FRANKLIN GLACIER, BRITISH COLUMBIA, CANADA


MOOD, Bryan J. and SMITH, Dan J., University of Victoria Tree-Ring Laboratory, Department of Geography, University of Victoria, PO Box 3060 STN CSC, Victoria, BC V8W 3R4, Canada

Franklin Glacier is an 18 km long trunk valley glacier flowing from the west face of Mt Waddington, British Columbia, Canada. Radiocarbon-dated subfossil wood samples from the proximal faces of lateral moraines flanking Franklin Glacier show that it expanded into standing forests numerous times during the late glacial and Holocene. The glacier advanced during the Younger Dryas chronozone at 12911-12691 cal yr BP following the initial down wastingat the end of the last glacial maximum at c. 16000 cal yr BP. During the early Holocene, Franklin Glacier appears to have retreated significantly, leaving no record of expansion until 6356-6285 where it expanded into a standing forest located close to the contemporary ice surface position. Two progressively larger advances occurred following this initial expansion at 5472-5284 and 4772-4577 cal yr BP where it achieved ice levels close to its late Holocene maximum position. This period was followed by down wasting and several intervals of ice expansion at 4257-4084 and 3211-3021 cal yr BP. Franklin Glacier subsequently advanced into a mature standing forest (> 224 years in age) at 2621-2377 cal yr BP then subsequently down wasted and was expanding down valley by 1573-1476 cal yr BP when it overrode young sub alpine fir trees. During the Little Ice Age, the glacier advanced multiple times at 801-676, 608-555, and 570-509 cal yr BP which saw Franklin Glacier reach its late Holocene maximum position. The glacier remained close to its late Holocene maximum until the early 20th century where it has since down wasted and retreated substantially. The record of glacier activity from Franklin Glacier is the most comprehensive recovered from the Coast Mountains and showcases the complexity of mid- and late Holocene glacier behaviour in the region.