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Fieldwork in the Blackstone Uplands (August 2nd to 22nd, 2018) was uneventful this year, although the weather was rather cold and rainy. Below are some photos of Maude (who joined the trip to lend a hand), Pascale, and baby-Florent in the field.
Pascale visiting the basin of a drained seasonal pond
Maude setting up temperature sensors in a thermokarst initiation feature
Pascale and Florent downloading data loggers
Pascale (and baby Florent!) participated in the 2018 Yellowknife Geoscience Forum, which had a very good turn out of permafrost scientists!
Pascale presented a poster with some data and thought son the Evolution of incipient lowland thermokarst features in the Blackstone River valley, Yukon (abstract on p. 108 of the Forum’s book of abstracts).
Pascale also presented a brief overview of the thermal monitoring and geomorphological mapping work carried by Maare Packalen, Jim McLaughlin, and Zlatka Pironkova in Ontario Far North. See Permafrost monitoring in the Hudson Bay Lowlands: preliminary results from the Ontario Far North in the Forum’s book of abstracts, p. 60.
The stirring committee of the new Canadian Permafrost Association used the opportunity to have a fruitful meeting in person. The new association should be up and running this summer! Kumari Karunaratne and Toni Lewkowicz gave a presentation to update the community and gather input regarding the mission statement, logo, etc. See The formation of a Canadian permafrost association in the abstract book of the Forum, p. 44.
Welcome to our newest and smallest lab member, Florent Léveillée-Renard, born on June 26th, 2017. Florent went on his first field trip to the Yukon with Pascale this summer, at the age of 2 months. He was great help while visiting field sites along the Dempster highway.
Methane escapes from a hole drilled through lake bottom sediment (photo credit: Z. Braul)
A paper published by Roy-Leveillee and Burn (2017) in the Journal of Geophysical Research- Earth Surface reports observations of permafrost degradation and talik development beneath water depths less than 15% of the maximum ice thickness in lakes of Old Crow Flats, northern Yukon. This is surprising as, in the near-shore zones of thermokarst lakes, it is generally assumed that permafrost is sustained where water depth is less than 60% of the local maximum ice thickness.
Jet-drilling to delineate the talik permafrost boundary (Photo credit: P. Roy-Léveillée)
The paper investigates controls on permafrost degradation and reveals that sub-lake permafrost is sensitive to on-ice snow distribution where the water column freezes through. It shows the importance of the thermal offset where conditions are marginal for talik initiation and highlights the role of interannual variability for prompt talik initiation near receding shores.
These findings improve understanding of permafrost degradation beneath shallow water, a topic of particular concern in the context of climatic warming as methane release from thaw lakes is concentrated near receding lake margins and is most active at the thaw front beneath the lake bottom.
In July and August, Emma, Nathan, and Pascale visited the Blackstone Uplands, Yukon, to investigate field conditions at sites that showed signs of increased permafrost degradation between the 1950s and early 2000s. The data collected will be used for Emma’s honor thesis, as she will examine the distribution of thermokarst features in the Blackstone River valley and discuss terrain characteristics at the affected sites.
Photographs of thermokarst features in the Blackstone Uplands and some field work photos are found here, and more pictures of students hard at work in the field are found here. Nathan and Emma’s field work was made possible by funding from the Goodman School of Mines and the Northern Scientific Training Program. Thanks to the Na-Cho Nyak Dun and Tr’ondëk Hwëch’in First Nations for allowing us to conduct field work on their traditional territories.
Clockwise from top left corner: Degrading ice wedges and thermokarst tunnels; Expanding ponds; Active-layer detachment slides; Developping beaded streams. All photos taken in the Blackstone Uplands in 2016, by Pascale Roy-Leveillee.