Le pergélisol au Québec nordique : bilan et perspectives

Allard, Michel; Séguin, Maurice K.

doi:10.7202/032671ar

Cited by 89 publications

(64 citation statements)

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“…BP). Climate cooling during the Neoglacial period (~3200 BP) led to a decrease in peat accumulation and drying of the soil surface due to growth of ground ice (Allard and K.-Seguin, 1987).…”

Section: Study Regionmentioning

confidence: 99%

Landscape-gradient assessment of thermokarst lake hydrology using water isotope tracers

Narancic

Wolfe

Pienitz

et al. 2017

Journal of Hydrology

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Please cite this article as: Narancic, B., Wolfe, B.B., Pienitz, R., Meyer, H., Lamhonwah, D., Landscape-gradient assessment of thermokarst lake hydrology using water isotope tracers, Journal of Hydrology (2016), doi: http:// dx.doi.org/10. 1016/j.jhydrol.2016.11.028 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.1 Landscape-gradient assessment of thermokarst lake hydrology using water isotope -Water isotopes are used to characterize thermokarst lake hydrology in Nunavik, Canada.-Rainfall and/or permafrost meltwater are the main lake water sources.-Maritime climate enhances the hydrological resiliency of thermokarst lakes.-Terrestrial carbon inputs from surface runoff are likely to increase in the future.-Thermokarst lakes will persist and methane emissions are likely to increase.3 ABSTRACT Thermokarst lakes are widespread in arctic and subarctic regions. In subarctic Québec (Nunavik), they have grown in number and size since the mid-20 th century.Recent studies have identified that these lakes are important sources of greenhouse gases. This is mainly due to the supply of catchment-derived dissolved organic carbon that generates anoxic conditions leading to methane production. To assess the potential role of climate-driven changes in hydrological processes to influence greenhouse-gas emissions, we utilized water isotope tracers to characterize the water balance of thermokarst lakes in Nunavik during three consecutive mid-to late summer seasons (2012)(2013)(2014). Lake distribution stretches from shrub-tundra overlying discontinuous permafrost in the north to spruce-lichen woodland with sporadic permafrost in the south.Calculation of lake-specific input water isotope compositions ( I ) and lake-specific evaporation-to-inflow (E/I) ratios based on an isotope-mass balance model reveal a narrow hydrological gradient regardless of diversity in regional landscape characteristics. Nearly all lakes sampled were predominantly fed by rainfall and/or permafrost meltwater, which suppressed the effects of evaporative loss. Only a few lakes in one of the southern sampling locations, which overly highly degraded sporadic permafrost terrain, appear to be susceptible to evaporative lake-level drawdown. We attribute this lake hydrological resiliency to the strong maritime climate in coastal regions of Nunavik. Predicted climate-driven increases in precipitation and permafrost degradation will likely contribute to persistence and expansion of thermokarst lakes throughout the region. If coupled with an increase in terrestrial carbon inputs to thermokarst lakes from surface runoff, conditions favorable for mineralizatio...

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Section: Study Regionmentioning

confidence: 99%

Landscape-gradient assessment of thermokarst lake hydrology using water isotope tracers

Narancic

Wolfe

Pienitz

et al. 2017

Journal of Hydrology

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“…The Salluit region was scoured by the Laurentide ice sheet, and Sugluk Fjord was deglaciated circa 8000-7500 yr BP (Gray et al, 1993;Kasper and Allard, 2001). The area is in the continuous permafrost zone and is characterized by an active periglacial morphoclimatic system (Allard and Séguin, 1987;Kasper and Allard, 2001). The present-day regional climate is semiarid Arctic, with polar temperatures and a very short growing season (Gérardin and McKenney, 2001).…”

Section: Study Sitementioning

confidence: 99%

Bone Weathering in a Periglacial Environment: The Tayara Site (KbFk-7), Qikirtaq Island, Nunavik (Canada)

Todisco¹,

Monchot²

2009

ARCTIC

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ABSTRACT. Bone weathering analysis of the Palaeoeskimo Tayara site (Qikirtaq Island, Nunavik, Canada) documents site taphonomy in the Arctic periglacial environment. Like a majority of sites in the eastern Canadian Arctic, Tayara has a faunal assemblage dominated by marine mammals (seal, walrus, and beluga whale) and some terrestrial mammals (caribou, fox, and bear). Statistical and spatial analyses of five weathering stages reveal that large mammal bone preservation is generally good and does not seem to be influenced by taxonomic and skeletal differences. The good preservation of the faunal assemblage seems to have been favored by the burial of bones and their incorporation into the active layer, which suggests only limited mechanical deterioration (i.e., freeze-thaw or wet-dry cycles, or both) before or at the time of burial. Burial depth partly explains the degree of bone weathering. Indeed, the well-preserved bones are found mainly where burial is associated with thicker overlying sediments. This implies rapid bone burial with a low degree of exposure to temperature changes and atmospheric processes. However, analysis also shows the presence of highly weathered bones where burial is associated with thicker overlying sediments. Consequently, differential bone depth probably does not explain all bone-weathering variability within the site. These results show the importance of examining bone weathering before any archaeozoological and paleoethnographic interpretations.Key words: bone weathering, taphonomy, large mammals, periglacial environment, spatial analysis, Palaeoeskimo RÉSUMÉ. L'analyse méthodique de la météorisation osseuse des restes fauniques du site paléoesquimau de Tayara (île Qikirtaq, Nunavik, Canada) documente la taphonomie d'un site archéologique en contexte périglaciaire arctique. Comme dans la plupart des sites arctiques de l'Est canadien, l'assemblage faunique de Tayara est dominé par des mammifères marins (phoque, morse et béluga) plus quelques mammifères terrestres (caribou, renard et ours). Les analyses statistiques et spatiales selon cinq stades d'altération reconnus montrent une bonne conservation des restes osseux des grands vertébrés, qui ne semble pas être influencée par les différences taxonomiques et squelettiques. La bonne conservation de l'assemblage osseux semble avoir été favorisée par l'enfouissement des ossements et leur incorporation dans la couche active. Ceci suggère une détérioration mécanique pré-et synenfouissement limitée (i.e., cycles gel-dégel et/ou d'hydratation-dessiccation). La profondeur d'enfouissement explique en partie le degré de préservation des ossements. En effet, les ossements les mieux conservés se rencontrent principalement dans les zones où les sédiments de recouvrement sont les plus épais. Ceci implique un enfouissement rapide ainsi qu'un faible degré d'exposition des ossements aux changements de température et aux processus atmosphériques. Les analyses montrent aussi la présence de quelques os fortement détériorés situés dans les zones où les sédimen...

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“…The region is located in the zone of continuous permafrost (Allard and Séguin, 1987). The prevailing climate is a cold and dry Arctic climate.…”

Section: Physical Settingmentioning

confidence: 99%

Paleoenvironmental Reconstruction and Timeline of a Dorset-Thule Settlement at Quaqtaq (Nunavik, Canada)

Bhiry

Marguerie

Lofthouse

2016

Arctic, Antarctic, and Alpine Research

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International audienceA geoarchaeological and paleobotanical study of a Paleoeskimo and Neoeskimo site was undertaken in order to reconstruct site-formation processes. The study site JfEl-10 is located on Igloo Island, in Diana Bay, on the southern shore of Hudson Strait. It contains a peat-mineral deposit situated between two successive beach crests, close to a small marsh. Samples from the edge of the site, which consists of a remarkable section of stratigraphy 60 cm thick that contains alternating brown organic beds and light-colored sand beds, were examined in the laboratory. Macrofossil data and pollen data were used to reconstruct the local and regional vegetation and to determine climatic changes over the past 1200 years. The geoarchaeological study includes the stratigraphy and the sedimentology of archaeological sediments. The evolution of the site followed three successive environmental phases, and the site was home to two distinct cultures. The first phase (from ca. 1200 to ca. 950 cal. yr B.P.) was characterized by cold and mesic conditions and the Dorset occupation. In the second phase, conditions became more humid beginning ca. 950 cal. yr B.P. and lasted for approximately 450 years. This period is marked by the arrival of Thule Inuit, who hunted marine mammals in the vicinity. Zooarchaeological information indicated a fall/winter occupation during the Thule Inuit period. The third phase corresponds with the onset of the Little Ice Age (A.D. 1500–1850) and associated cooling. During this time, the Thule Inuit abandoned the site. If the increased cooling caused an earlier freeze-up of Diana Bay, this may have prevented the movement of walrus to their haul-out island during fall. Additionally, the faster accumulation of thick ice would have limited the hunting of seals through their breathing hole

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Le pergélisol au Québec nordique : bilan et perspectives

Cited by 89 publications

References 57 publications

Landscape-gradient assessment of thermokarst lake hydrology using water isotope tracers

Landscape-gradient assessment of thermokarst lake hydrology using water isotope tracers

Bone Weathering in a Periglacial Environment: The Tayara Site (KbFk-7), Qikirtaq Island, Nunavik (Canada)

Paleoenvironmental Reconstruction and Timeline of a Dorset-Thule Settlement at Quaqtaq (Nunavik, Canada)

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