Mid-Holocene glacier expansion between 7500 and 4000 cal. yr BP in the British Columbia Coast Mountains, Canada

Abstract

The mid-Holocene behaviour of five glaciers in the British Columbia Coast Mountains was reconstructed from radiocarbon ages and stratigraphic analysis. Subfossil wood evidence at Canoe, Fyles, Jacobsen, Tchaikazan and Icemaker glaciers suggests these glaciers were expanding into standing forests prior to 6630, 4900 and 4200 cal. yr BP. Stratigraphically constrained woody detritus at Fyles Glacier records the progradational history of a Gilbert-type delta forming in response to glacial expansion between 7020 and 5470 cal. yr BP. This research provides the first evidence for mid-Holocene glacial expansion in the central and northern British Columbia Coast Mountains. Proxy records describing mid-Holocene climates in the British Columbia Coast Mountains indicate a trend towards slightly cooler and possibly wetter conditions than present. Glacial expansion occurring between 7500 and 4000 cal. yr BP has regional correlatives, suggesting coherent broad-scale climate forcing mechanisms influenced glacial mass balance at this time.