Cryostratigraphy, carbon and nitrogen content and <sup>14</sup>C dating of permafrost cores from sites across the Canadian Arctic
Abstract
Sustainability of existing infrastructure and new projects in the Arctic rely on a detailed knowledge of the thermal and geotechnical properties of permafrost, which is required to adopt appropriate maintenance and construction practices and select proper structural and thermal engineering designs. Physical properties of permafrost are also used as input variables for the parameterization in thermal modelling and thaw settlement predictive models.
These data series were obtained following the ADAPT permafrost drilling protocol. For lower latitude sites, the top 2 meters of the permafrost, which do not include the active layer, was sampled. At higher latitudes in the continuous permafrost zone where it was difficult to drill into permafrost, only the first meter of permafrost was drilled. Each ADAPT site had two subsites. At each subsite, two boreholes were drilled into the permafrost table(for a maximum of 4 boreholes per ADAPT site) from the base of one of the three soil pits used for the active layer soil sampling.
The frozen cores were recovered for analysis of physical properties (ground ice content and structure, ground water content, grain-size determination, laboratory tests for thermal conductivity measurements) and carbon content. The top and bottom of each core segments (core segments had a maximum length of 30 cm ) were sub-sampled for C-H -N determination giving a minimum of 4 sub-samples per 30 cm. All sub-samples were analysed at the Centre d'études nordiques (CEN) Radiocarbon Dating Laboratory of the CEN, where the total mass content of carbon (C), nitrogen (N) and hydrogen (H) were also analysed, by combustion using a LECO CHN628 Elemental Analyzer. All permafrost sub-samples were 1) weighed for the determination of the bulk density of the soil, 2) dried and weighed again to determine the water content, and 3) ground and mixed using a mortar and pestle before a subsample was removed and analyzed. Conventional 14C dating was done at the CEN Radiocarbon Laboratory, and samples for 14C-AMS dating were prepared at CEN and dated at the University of California Riverside radiocarbon facility.
Cryostratigraphic analyses were done by X-ray computed tomography scans (CT-scans) of frozen cores with a Siemens Somatom 64 scanner at the Institut National de la Recherche Scientifique (INRS-ETE) in Québec City. The CT-Scan method is is a non-destructive (thus preserving sample integrity) approach to determine the physical properties of permafrost in undisturbed samples. The cores were scanned over their entire length with a slice thickness of 0.6 mm. According to the core diameter (100 mm), a pixel resolution of 0.2 x 0.2 mm is provided. By selecting a range of tomographic intensity values corresponding to each of the soil components (sediment, ice and gas), voxel classification and quantification of the soil components are achieved using a MATLAB script, therefore providing the fractional volume of the permafrost samples components (soil phase-diagram).
The cryostratigraphic, carbon, nitrogen, water content, and 14C data analyses were done on samples from 9 ADAPT sites: Arviat, Beaver Creek, Daring Lake, Vallée des Trois (VDT- Umiujaq), BGR (Umiujaq), SAS (Kuujjuarapik), Ward Hunt Island, Bylot Island and Churchill. Further details on ADAPT Standard Protocols are given at the ADAPT website.
These data series were obtained following the ADAPT permafrost drilling protocol. For lower latitude sites, the top 2 meters of the permafrost, which do not include the active layer, was sampled. At higher latitudes in the continuous permafrost zone where it was difficult to drill into permafrost, only the first meter of permafrost was drilled. Each ADAPT site had two subsites. At each subsite, two boreholes were drilled into the permafrost table(for a maximum of 4 boreholes per ADAPT site) from the base of one of the three soil pits used for the active layer soil sampling.
The frozen cores were recovered for analysis of physical properties (ground ice content and structure, ground water content, grain-size determination, laboratory tests for thermal conductivity measurements) and carbon content. The top and bottom of each core segments (core segments had a maximum length of 30 cm ) were sub-sampled for C-H -N determination giving a minimum of 4 sub-samples per 30 cm. All sub-samples were analysed at the Centre d'études nordiques (CEN) Radiocarbon Dating Laboratory of the CEN, where the total mass content of carbon (C), nitrogen (N) and hydrogen (H) were also analysed, by combustion using a LECO CHN628 Elemental Analyzer. All permafrost sub-samples were 1) weighed for the determination of the bulk density of the soil, 2) dried and weighed again to determine the water content, and 3) ground and mixed using a mortar and pestle before a subsample was removed and analyzed. Conventional 14C dating was done at the CEN Radiocarbon Laboratory, and samples for 14C-AMS dating were prepared at CEN and dated at the University of California Riverside radiocarbon facility.
Cryostratigraphic analyses were done by X-ray computed tomography scans (CT-scans) of frozen cores with a Siemens Somatom 64 scanner at the Institut National de la Recherche Scientifique (INRS-ETE) in Québec City. The CT-Scan method is is a non-destructive (thus preserving sample integrity) approach to determine the physical properties of permafrost in undisturbed samples. The cores were scanned over their entire length with a slice thickness of 0.6 mm. According to the core diameter (100 mm), a pixel resolution of 0.2 x 0.2 mm is provided. By selecting a range of tomographic intensity values corresponding to each of the soil components (sediment, ice and gas), voxel classification and quantification of the soil components are achieved using a MATLAB script, therefore providing the fractional volume of the permafrost samples components (soil phase-diagram).
The cryostratigraphic, carbon, nitrogen, water content, and 14C data analyses were done on samples from 9 ADAPT sites: Arviat, Beaver Creek, Daring Lake, Vallée des Trois (VDT- Umiujaq), BGR (Umiujaq), SAS (Kuujjuarapik), Ward Hunt Island, Bylot Island and Churchill. Further details on ADAPT Standard Protocols are given at the ADAPT website.
Data citation
ADAPT 2016. Cryostratigraphy, carbon and nitrogen content and <sup>14</sup>C dating of permafrost cores from sites across the Canadian Arctic, v. 1.0. Nordicana D25, doi: 10.5885/45427AD-06F05740704B4CA3.
Location map
Contributors
Allard, Michel
Centre d'études nordiques, Université Laval
Lemay, Mickaël
ArcticNet/Centre d'études nordiques, Université Laval
Fortier, Daniel
Université de Montréal
Grogan, Paul
Queen's University
Berteaux, Dominique
Université du Québec à Rimouski
Burn, Christopher
Carleton University
Doré, Guy
Centre d'études nordiques, Université Laval
Gauthier, Gilles
Centre d'études nordiques, Université Laval
Grant, Robert
University of Alberta
Henry, Greg
University of British Colombia
Lamoureux, Scott
Queen's University
Lévesque, Esther
Université du Québec à Trois-Rivières
Pienitz, Reinhard
Centre d'études nordiques, Université Laval
Roulet, Nigel
McGill University
Vincent, Warwick F.
Centre d'études nordiques, Université Laval
Wolfe, Brent
Wilfrid Laurier University
Acknowledgements
The ADAPT team would like to thank all ADAPT HQPs, field and research assistants from the 15 ADAPT laboratories as well as many close collaborators that contributed to the CHN database in applying the standard protocols all across the Canadian Arctic. A special thank to the CEN’s research assistants, Jonathan Roger, Andrée-Sylvie Carbonneau, Denis Sarrazin, Emmanuel L’Hérault, Guillaume Labrecque, Ariane Beauféray-Marais and Luc Cournoyer for their precious help for the sample and data management.
Polar Data Catalogue links (Metadata)
Version history
-
Version 1.0 (2013–2014)Updated August 16, 2016
You can request an older version by contacting nordicana@cen.ulaval.ca
Measurement sites
| Site | Latitude | Longitude | Altitude (m) | Information Forages/<br>Borehole logs | |
|---|---|---|---|---|---|
| Arviat | 61.09793 | -94.11942 | More info | ||
| Beaver Creek | 62.33624 | -140.83206 | More info | ||
| BGR (MA) | 56.61639 | -76.22083 | More info | ||
| Bylot Island | 73.15039 | -80.00474 | More info | ||
| Churchill | 58.72716 | -93.83666 | More info | ||
| Daring Lake | 64.86667 | -111.55 | More info | ||
| Iqaluit | 63.75639 | -68.55583 | More info | ||
| SAS2 | 55.22615 | -77.69585 | More info | ||
| Umiujaq | 56.54778 | -76.46194 | More info | ||
| Ward Hunt Island | 83.05381 | -74.09365 | More info |
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