Origin and Age of Tabular Massive Ice and Ice Wedges in the Smoking Hills, Northwest Territories, Canada

Abstract

The Smoking Hills area is located in the Northwest Territories, Canada. It contains many retrogressive thaw slumps that expose different permafrost units, including tabular massive ice and ice wedges. This study investigates the origin and age of these ice bodies to refine the glacial and permafrost history of the Smoking Hills region. Using cryostratigraphic observations, stable water isotope analysis, major ion geochemistry, and radiocarbon dating, samples from four retrogressive thaw slumps headwalls were analyzed. The results suggest that three of the sites contained buried glacial ice deposited during the Late Wisconsinan glaciation. Deformed and truncated ice wedges at one of the sites also show evidence of a glacial retreat during the Bølling–Allerød interstadial followed by a short glacial re-advance before of during the Younger Dryas. Holocene-aged ice wedges from a second retrogressive thaw slumps reflect the re-establishment of permafrost after the Wisconsin glaciation. Chemical anomalies in some ice units indicate a possible influence from the Smoking Hills Formation on Holocene-aged ground ice. These results highlight a dynamic glacial and permafrost history in the region.