| Title | Re-evaluating the relevance of vegetation trimlines in the Canadian Arctic as an indicator of Little Ice Age paleoenvironments |
| Author | Wolken, G J; England, J H; Dyke, A S |
| Source | Arctic vol. 58, no. 4, 2005 p. 341-353, https://doi.org/10.14430/arctic448 (Open Access) |
| Links | Abstract - Résumé
|
| Year | 2005 |
| Alt Series | Earth Sciences Sector, Contribution Series 2004247 |
| Publisher | The Arctic Institute of North America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Nunavut |
| NTS | 27; 28; 29; 37; 38; 39; 47; 48; 49; 57; 58; 59; 67; 68; 69; 77; 78; 79; 87; 88; 89; 97; 98; 99; 120; 340; 560 |
| Area | Canadian Arctic; Canadian Arctic Archipelago; Queen Elizabeth Islands |
| Lat/Long WENS | -128.0000 -60.0000 84.0000 68.0000 |
| Subjects | surficial geology/geomorphology; Nature and Environment; Recent; paleoenvironment; paleoclimatology; glaciation; neoglaciation; glaciers; vegetation; trimlines; snow; carbonate rocks; climate; Little
Ice Age; Lichen; climate change; plateau ice caps; seasonal snow cover; climate indicators; equilibrium-line altitude (ELA); Cenozoic; Quaternary |
| Illustrations | sketch maps; photographs; aerial photographs; cross-sections; models |
| Program | Reducing Canada's Vulnerability to Climate
Change |
| Program | NSERC Natural Sciences and Engineering Research Council of
Canada |
| Program | University of Alberta,
Canadian Circumpolar Institute, Northern Research Grants |
| Released | 2010 01 29 |
| Abstract | The origin of trimlines associated with the so-called "lichen-free" areas in the Canadian Arctic has been attributed both to perennial snowfield expansion during the Little Ice Age (LIA) and to
seasonally persistent snow cover in more recent times. Because of the disparate hypotheses (ecological versus paleoclimatic) regarding the formation of these trimlines, their use as a paleoclimatic indicator has been abandoned for more than two
decades. We re-examine this debate and the validity of the opposing hypotheses in the light of new regional mapping of trimlines across the Queen Elizabeth Islands (QEI). The ecological hypothesis-insufficient duration of the growing season resulting
from seasonally persistent snow cover-fails to account for the poikilohydric nature of lichens and their ability to endure short growing seasons. It cannot adequately explain the existence of sharp trimlines or account for the occurrence of those
trimlines on sparsely vegetated carbonate terrain. Furthermore, trimlines outlining the former extent of thin plateau ice caps are accordant with trimlines associated with former perennial snowfields, indicating that these trimlines record snow and
ice expansion during the LIA rather than the seasonal persistence of more recent snow cover. We suggest that these features represent an important LIA climate indicator and should therefore be used for paleoclimatic reconstruction. |
| GEOSCAN ID | 216220 |
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