التفاصيل البيبلوغرافية
| العنوان: |
Re-evaluating the Relevance of Vegetation Trimlines in the Canadian Arctic as an Indicator of Little Ice Age Paleoenvironments |
| المؤلفون: |
Wolken, Gabriel J., England, John H., Dyke, Arthur S. |
| المصدر: |
ARCTIC; Vol. 58 No. 4 (2005): December: 331–458; 341-353 ; 1923-1245 ; 0004-0843 |
| بيانات النشر: |
The Arctic Institute of North America |
| سنة النشر: |
2010 |
| المجموعة: |
University of Calgary Journal Hosting |
| مصطلحات موضوعية: |
trimlines, lichen-free areas, paleoenvironment, Little Ice Age, Arctic Canada, plateau ice caps, climate change, Neoglacial, lichens, seasonal snow cover, glaciers, épaulements, zones sans lichen, paléoenvironnement, petit âge glaciaire, Arctique canadien, calottes glaciaires des plateaux, changement climatique, néoglaciaire, couverture de neige saisonnière |
| الوصف: |
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. ; L’origine des épaulements propres aux zones dites sans lichen de l’Arctique canadien a été attribuée tant à l’expansion des champs de neige pérenne pendant le petit âge glaciaire qu’à la couverture de neige longévive d’époques plus récentes. Puisqu’il existe des hypothèses disparates (écologiques par opposition à paléoclimatiques) quant à la formation de ces épaulements, on a arrêté de s’en servir à titre d’indicateur paléoclimatique depuis plus d’une vingtaine d’années. Ici, ce débat fait l’objet d’un nouvel examen où l’on se penche sur la validité des hypothèses divergentes à la lumière du nouveau mappage régional des ... |
| نوع الوثيقة: |
article in journal/newspaper |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| Relation: |
https://journalhosting.ucalgary.ca/index.php/arctic/article/view/63509/47446; https://journalhosting.ucalgary.ca/index.php/arctic/article/view/63509 |
| الاتاحة: |
https://journalhosting.ucalgary.ca/index.php/arctic/article/view/63509 |
| رقم الانضمام: |
edsbas.7F939AE2 |
| قاعدة البيانات: |
BASE |