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TitleThe present state and future fate of permafrost: A paleoenvironmental perspective
AuthorWolfe, S A; Kokelj, S V
Source2016 Yellowknife Geoscience Forum, abstract and summary volume; by Irwin, D (ed.); Gervais, S D (ed.); Terlaky, V (ed.); Northwest Territories Geological Survey, Yellowknife Geoscience Forum Abstracts Volume 2016, p. 79
Alt SeriesEarth Sciences Sector, Contribution Series 20160275
PublisherNorthwest Territories Geological Survey (Yellowknife, Canada)
Meeting44th Annual Yellowknife Geoscience Forum; Yellowknife, NT; CA; November 15-17, 2016
Documentserial
Lang.English
Mediapaper
ProgramLand-based Infrastructure, Climate Change Geoscience
LinksOnline - En ligne (complete volume - volume complet, PDF, 1.72 MB)
AbstractThe geologic, geomorphic, biologic and climatic history of a landscape combines to dictate present-day thermal and physical state of permafrost. The timing and extent of these past environmental conditions provides a foundation for understanding present-day terrain conditions and prediction of future fate of permafrost. Much of Canada's northern landscape reflects a glacial legacy, with the resulting suite of glacial and post-glacial deposits having implications for the amount and type of ground ice retained today within permafrost. In addition, most near-surface permafrost has been environmentally-conditioned by processes occurring within the last 14,000 years, though in unglaciated regions this may be considerably longer.
We review the present-day thermal and physical state of permafrost in relation to modern, late Glacial, and Holocene environmental conditions in North America. We examine the distribution of modern biomes and the relation to present-day distribution and thermal state of permafrost. We then review past biome distributions in northern Canada, to examine major climate-driven environmental shifts that have affected permafrost regimes. Within this context, we discuss the distribution of various ground ice types. This includes the potential distribution of i) buried ice of glaciogenic origin in relation to glacial moraines and hummocky terrain and to glaciofluvial sediments (eskers, kames, and ice-contact deltas), ii) intra-sedimental ice (ice wedges and segregated ice) in relation to maximum (glacial) lake and marine limits. We highlight examples of how post-glacial landscapes and climatically-driven biome changes interact to influence the present-day sensitivity of permafrost to future changes. These include, i) preservation of glacigenic sediments and ground ice within continuous permafrost; ii) climate-driven ground-ice accumulation and/or degradation in relation to past biome changes; iii) chronosequences within lacustrine and marine sediments containing intra-sedimental ground ice in permafrost regions.
Summary(Plain Language Summary, not published)
The environmental history (geologic, geomorphic, biologic and climatic) is an inherited legacy that dictates present-day properties of permafrost. Knowledge of past environmental changes provides a foundation for considering variation in present-day conditions and prediction of future fate of permafrost. We review the present-day thermal and physical state of permafrost in relation to modern, late Glacial, and Holocene environmental conditions in North America. We examine the distribution of modern biomes and the relation to present-day distribution and thermal state of permafrost. The distribution of ground ice is assessed based on glacial and Holocene depositional environments. We review past biome distributions in northern Canada for major climate-driven environmental shifts that have affected permafrost conditions. We highlight regions (examples) where climate-driven biome changes have influenced permafrost conditions and the present-day sensitivity of permafrost to future changes.
GEOSCAN ID299445