Early Holocene glacier advance, southern Coast Mountains, British Columbia, Canada

Abstract

Terrestrial and lake sediment records from several sites in the southern Coast Mountains, British Columbia, provide evidence for an advance of alpine glaciers during the early Holocene. Silty intervals within organic sediments recovered from two proglacial lakes are bracketed by AMS 14 C -dated terrestrial macrofossils and Mazama tephra to 8780–6730 and 7940– 6730 14 C yr BP [10,150–7510 and 8990– 7510 cal yr BP]. Radiocarbon ages ranging from 7720 to 7380 14 C yr BP [8630– 8020 cal yr BP] were obtained from detrital wood in recently deglaciated forefields of Sphinx and Sentinel glaciers. These data, together with previously published data from proglacial lakes in the Canadian Rockies, imply that glaciers in western Canada advanced during the early Holocene. The advance coincides with the well-documented 8200-yr cold event identified in climate proxy data sets in the North Atlantic region and elsewhere.