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TitleSignificance of glacial landsystems and process-form regimes in permafrost terrain: the Smoking Hills region of northwestern Arctic Canada
AuthorSmith, RORCID logo; Evans, D; Gosse, J
SourceINQUA 2019: 20th Congress of the International Union for Quaternary Research, programme; O-5047, 2019 p. 1 Open Access logo Open Access
LinksOnline - En ligne
Alt SeriesNatural Resources Canada, Contribution Series 20180353
PublisherInternational Union for Quaternary Research
MeetingINQUA 2019: 20th Congress of the International Union for Quaternary Research; Dublin; IE; July 25-31, 2019
DocumentWeb site
Mediaon-line; digital
File formathtml; pdf
NTS97B; 97C
AreaSmoking Hills; Horton River
Lat/Long WENS-128.0000 -126.0000 69.5000 68.5000
Subjectssurficial geology/geomorphology; stratigraphy; Nature and Environment; Science and Technology; permafrost; ground ice; glacial history; deformation; landslides; slumps; glacial deposits; tills; glacial landforms; Amundsen Gulf Ice Stream; Phanerozoic; Cenozoic; Quaternary
ProgramGEM2: Geo-mapping for Energy and Minerals Western Arctic Sverdrup Basin
Released2019 07 01
AbstractIn northern Canada, considerations of natural resource potential include not simply identification of a resource itself, but also an understanding of aspects of engineering geology of surficial and shallow bedrock materials within formerly glaciated terrain, particularly in areas of ice-rich permafrost. Hence, understanding the landscape is not simply a surficial geology mapping exercise, but more an integrated consideration of the evolution of the landsystem and the inherent process-form regimes. As part of the Geological Survey of Canada's GEM2 research program, this study examined the Smoking Hills region of northwestern Arctic Canada (~69°N; 127°W). While parts of this area were previously reported as unglaciated during the last (Late Wisconsinan) glaciation, new glaciological models and field studies argue that the entire region was glaciated, and that the study area was situated south of the westward-flowing Amundsen Gulf Ice Stream. A unique older glacial stratigraphy (3-5 separate glaciations) is preserved in the region, for which an improved chronology based on cosmogenic nuclide burial dating and a stratigraphic reinterpretation is being undertaken.
Regionally exposed bedrock and complex Quaternary stratigraphies located in incised valleys document a range of past glacial processes, and in particular extensive glaciotectonic deformation and entrainment of poor to weakly-consolidated Cretaceous sedimentary bedrock. Glaciotectonic features include deformed intraclasts of coherent bedrock ranging from thin (<1 cm) stringers and blocks to large metre-scale boudins, cohesive bedrock rafts (metres to 10s of metres thick) and acute to overturned fold structures ?100 m in vertical height. Extensive preglacial bedrock slumping along valleys likely contributed much of the entrained bedrock material, however, sections of deformed bedrock in valley walls also clearly demonstrate regional-scale, thin-skinned glaciotectonic deformation. Southward directed, arcuate, en echelon ridges on either side of the Horton River valley in an area of thin (0-2 m), discontinuous till cover expose massive ice and ice-rich debris that is interpreted as glacial thrusting of proglacial sediments, possibly buried glacial ice, and underlying bedrock. Elsewhere thick (up to 12 m) layers of buried glacial ice in valley bottoms suggests the potential for long-term preservation and re-incorporation by subsequent glaciations. The ice-thrust ridges are amongst the only regional-scale surface landforms recognized in the area (i.e. no extensive fluting or drumlin fields), suggesting that while the presence of patchy till cover indicates warm-based conditions, the thin-skinned tectonics and buried glacier ice, reflect localised basal freeze-on. Thicker tills within the complex stratigraphies of the buried valleys yield clast macrofabrics indicative of long term ice flow from the east or northeast. The evolution of this landsystem signature likely requires transitory changes in glacier basal thermal regimes possibly in association with advance and retreat of the adjacent westward-flowing Amundsen Gulf Ice Stream.
Summary(Plain Language Summary, not published)
This study presents results of fieldwork undertaken by the GEM-2 Smoking Hills activity. It highlights aspects of the region¿s glacial history and integrates these into a broader study of the overall landsystem that connects glacial and geological processes with identified landforms and stratigraphy. These are then considered in the context of engineering geology, and how this can be applied to the study and assessment of glaciated arctic permafrost environments. It is being presented at a conference of international peers, and a special session considering advances in glacial and periglacial landsystems and their implications for engineering geology.

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