CGRG Bibliography of Canadian Geomorphology
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Author : Carbonneau, A-S.; and Allard, M.
Date : 2010.
Title : Holocene geomorphic evolution and characterization of permafrost in Pangnirtung, Baffin Island.
Publication : 7th Annual ArcticNet Scientific Meeting. December 15-17, 2010. The Westin Ottawa, Ottawa,Ontario.
Issue : Programme.
Page(s) : 105.
Abstract
Climate change has an impact on urban development and infrastructures in the Arctic as permafrost temperature and active layer depth increase. Such changes can impact the stability upon thaw of the frozen ground and the infrastructures that are built on it. Therefore, it is important to enhance our knowledge on permafrost conditions as well as on surficial geology in order to assess the impact of climate change on permafrost, to evaluate risk to man- made infrastructures and to facilitate land use planning decision-making. This concern is particularly important for Pangnirtung as the Hamlet is located on a limited territory with ice-rich soils. Furthermore, the Hamlet has been affected in June 2008 by an extreme peak discharge of the Duval River, which flows across the center of the community, leading to permafrost degradation and instability of the terrain along the banks of the river. Methods used for this project were based on geophysical and geomorphological approaches, including permafrost cores drilled in superfi cial deposits and ground penetrating radar surveys. A preliminary surficial map demonstrates that four major terrain units make up the landscape in Pangnirtung: 1- The sloping terrace covered by colluvial material to the east of the Duval River, 2- The alluvial terrace with boulders and eroded channels along the banks of the Duval river, 3- The Holocene debris fan of the Duval river, and 4-A rocky promontory covered with marine silts and sands. Also, interpretations of four ground penetrating radar profiles correlate the preliminary interpretation of the surficial deposits of the community. Furthermore, one of the profiles reveals many hyperbolic reflectors interpreted as multiple ice wedges across terrain unit 1. Field observations also suggest the presence of ice wedges as numerous possible thermal contraction cracks were observed in this sector. Laboratory analysis using CT-Scan imagery, a non destructive method, and destructive methods (e.g. water contents determinations and grain-size analyses) will allow a detailed characterization of permafrost in terms of cryostructure and ice contents. Moreover, the thermal regime of permafrost in different surfi cial deposits will be analysed using ground temperature data from automated thermistor cables installed in August 2009. Ultimately, the new geotechnical information will be used to produce a map of permafrost conditions in the community and its surroundings to support the community expansion program that is needed due to demographic growth.
Bibliography of Canadian Geomorphology