A holocene ice-core pollen record from Ellesmere Island, Nunavut, Canada

A Holocene record of pollen deposition was obtained from an ice core drilled through the Agassiz Ice Cap. The pollen records long-range atmospheric transport to the ice cap. Pollen concentrations were highest in the early Holocene (similar to 15 grains/L), decreased in the mid-Holocene (similar to 6 grains/L), and increased in the late Holocene (similar to 9 grains/L), In the early Holocene, the higher concentration of tree pollen at a time when large parts of Canada were still ice-covered, and when forest was generally farther away, implies that atmospheric circulation was stronger than at present. Following deglaciation, as vegetation migrated north in central and eastern Canada, sources of pollen were closer to the Agassiz Ice Cap. However, the concentration of tree pollen decreased on the ice cap. This was followed by several relatively rapid changes after 3500 yr ago. Until ca, 3500 yr ago, the pollen concentration curves resembled the ice core delta(18)O and summer melt layer curves, both regarded as temperature proxies. (C) 2000 University of Washington.