Physical and temporal factors controlling the development of near-surface ground ice at Illisarvik, western Arctic coast, Canada

• Published in: Canadian Journal of Earth Sciences
• Main Authors: O’Neill, H. Brendan, Burn, C.R.
• Other Authors: Gajewski, Konrad
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2012
• Subjects: Ice; permafrost; Richards Island; Tundra
• Online Access: http://dx.doi.org/10.1139/e2012-043; http://www.nrcresearchpress.com/doi/full-xml/10.1139/e2012-043; http://www.nrcresearchpress.com/doi/pdf/10.1139/e2012-043

Near-surface permafrost was sampled in summer 2010 at 26 sites in the Illisarvik drained-lake basin and nine sites in the surrounding tundra on Richards Island, NWT, to investigate the growth of segregated near-surface ground ice. Permafrost and ground ice have developed in the lake basin since drainage in 1978. The lake bed soils are predominantly silts of varying moisture and organic-matter contents, with sandier soils near the lake margins. Excess-ice contents in the basin were also variable, and ice enrichment was observed to a maximum depth of 60 cm below the 2010 permafrost table. Shrub-covered, wet areas had the highest mean excess-ice content in the top 50 cm of permafrost (10%), while grassy, dryer areas (4%) and poorly vegetated marginal areas (<1%) were less enriched with ice. Site wetness was the most important variable associated with near-surface excess-ice content in the lake basin. Silt content was a secondary variable. Mean excess-ice content in the top 50 cm of permafrost at tundra sites (25%) was much greater than in the basin, with ice enrichment to greater depths, likely a result of the time available for permafrost aggradation since the early Holocene climatic optimum.