CGRG Bibliography of Canadian Geomorphology
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Author : Frechette, B.; Wolfe, A.P.; Miller, G.H.; de Vernal, A. and Richard, P.J.H.
Date : 2003.
Title : Evidence of an early Holocene thermal optimum in the eastern Canadian Arctic.
Publication : Canadian Geophysical Union. Annual Meeting, May 10 -14, 2003. Banff Centre, Banff, Alberta.
Issue :
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Abstract
Early Holocene paleoclimatic records from the eastern Canadian Arctic are the subject of debate because of apparent contradictions between terrestrial, marine, and ice core proxies. Some terrestrial proxies suggest cooler than present conditions before 8000 cal BP, despite peak Holocene summer insolation that produces a warm response in other records. The pollen record has proven especially enignmatic, given the potential complications of low local production and delayed plant colonization. Here, we present new pollen data from 2 lakes on Cumberland Peninsula, Baffin Island, which strongly suggest that early Holocene summer climates were significantly warmer than present. Early Holocene sediments from Lake Fog (67°11’N, 63°15’W, 460 m asl) and Lake Akvaqiak (66°47’N, 63°57’W, 45 m asl), dated by AMS 14 C on macrofossils and humic acids, each have Betula (shrub birch) pollen influxes about 15 times greater than those registered in mid- to late-Holocene units (8000 cal BP to present). Such high birch pollen percentages and fluxes imply the presence of local birch populations well north of modern distributional limits, presumably under an early Holocene climatic regime characterized by warm summers. Although the possibility of pollen redeposition exists for Fog lake, which is underlain by polleniferous interglacial sediments, Akvaqiak lake lies well within the Late Foxe glacial limit. The concordance of the two records implies that the early Holocene shrub pollen peaks are primary features of the regional early Holocene pollen rain, and thus reflect contemporaneous plant communities.
Bibliography of Canadian Geomorphology