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TitleGlacial landforms and sediments (landsystem) of the Smoking Hills area, Northwest Territories, Canada: implications for regional Pliocene-Pleistocene Laurentide Ice Sheet dynamics
AuthorEvans, D J A; Smith, I RORCID logo; Gosse, J C; Galloway, J MORCID logo
SourceQuaternary Science Reviews vol. 262, 106958, 2021 p. 1-50, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20200754
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNorthwest Territories
NTS97A/05; 97A/12; 97A/13; 97B/05; 97B/06; 97B/07; 97B/08; 97B/09; 97B/10; 97B/11; 97B/12; 97B/13; 97B/14; 97B/15; 97B/16; 97C; 97D/04; 97D/05; 97D/12; 97D/13; 97F; 107A/05; 107A/06; 107A/07; 107A/08; 107A/09; 107A/10; 107A/11; 107A/12; 107A/13; 107A/14; 107A/15; 107A/16; 107D; 107E
AreaSmoking Hills; Cape Bathurst; Parry Peninsula; Franklin Bay; Amundsen Gulf; Horton River
Lat/Long WENS-132.0000 -123.0000 70.7500 68.2500
Subjectssurficial geology/geomorphology; stratigraphy; geophysics; sedimentology; structural geology; geochronology; regional geology; geochemistry; Nature and Environment; Science and Technology; Pleistocene; Neogene; Pliocene; organic deposits; flood plains; terraces; deltas; channels; glacial deposits; glacial landforms; glacial features; tills; moraines; glacial flutings; ice flow; glacial lakes; tectonites; gravels; eskers; meltwater channels; kames; kettles; hummocks; glacial history; Wisconsinian glacial stage; glaciation; ice sheets; ice margins; deglaciation; ice retreat; interglacial stages; permafrost; ice wedges; paleomagnetic ages; paleomagnetic interpretations; systematic stratigraphy; stratigraphic correlations; burial history; glacial tectonics; faulting; faults, thrust; deformation; sedimentation; sediment reworking; radiometric dating; radiocarbon dating; paleogeography; lithofacies; Laurentide Ice Sheet; Beaufort Formation; Mason River Formation; Horton Gap; glaciofluvial sediments; glaciolacustrine sediments; ice streams; ice-flow directions; alluvial sediments; glaciofluvial outwash fan sediments; spillways; Phanerozoic; Cenozoic; Quaternary; Tertiary; Mesozoic; Cretaceous
Illustrationslocation maps; geoscientific sketch maps; digital elevation models; photographs; bar graphs; ternary diagrams; pie charts; plots; aerial photographs; satellite images; sketches; lithologic sections; stereonets; correlation sections; time series; tables
ProgramGEM2: Geo-mapping for Energy and Minerals Western Arctic, Tertiary Onshore, Smoking Hills
ProgramPolar Continental Shelf Program
Released2021 06 02
AbstractThe Smoking Hills area in the western Canadian Arctic was purported to contain a regionally rare Quaternary stratigraphic section with multiple, local ice cap-derived tills and a long chronology constrained by palaeomagnetic markers. We present a fundamental revision of previous glacial and magnetostratigraphic interpretations based on detailed sedimentological and structural analyses of the main stratigraphic section and many new exposures, cosmogenic nuclide isochron burial dating, and a systematic reconstruction of the geomorphology and landscape evolution using a glacial landsystem approach. We demonstrate that the Smoking Hills area was fully glaciated during the last (Wisconsinan) glaciation. Previously reported tills ascribed to multiple glaciations represent instead a complex facies sequence of glacitectonic thrust stacking of Laurentide Ice Sheet (LIS) sourced diamictons, glacilacustrine and glacifluvial deposits, together with previously unidentified, poorly-consolidated Cretaceous bedrock rafts and deformed intraclasts. Much of this sedimentation and glacitectonic activity dates to the last (Wisconsinan) glaciation and can be reconciled with a polythermal ice sheet marginal landsystem signature, wherein ice-cored moraine belts are developed over subglacial bedforms (flutings) arranged in discrete flowsets. The flowsets record the complex interaction of ice streams nourished by ice flowing from three main sources: Great Bear Lake to the south, Amundsen Gulf (Franklin Bay) to the east and Liverpool Bay (Mackenzie Valley) to the southwest. Decoupling of the ice margins of these three ice sources gave rise to interlobate ice-dammed lake development over the lower Horton River area during final deglaciation. A cosmogenic 26Al/10Be isochron burial age of 2.9 ± 0.3 Ma (1sigma, n = 4) from the lowermost glacial diamicton and glacitectonite sequence provides evidence of perhaps the earliest continental glaciation of this region. This deposit postdates, or is perhaps a later re-advance of the same initial glaciation that produced widespread glacitectonic disturbance of bedrock in preglacial valley networks and early glacifluvial and glacilacustrine deposits containing an ice wedge pseudomorph. Subsequent glaciations have largely removed or cannibalised pre-existing records to construct complex till and glacitectonite stacks that contain reworked organics with non-finite radiocarbon ages. One site preserves buried 'old' glacier ice in which prominent ice wedges had formed during an interglacial permafrost phase and were then deformed down-flow by the LIS during the Wisconsinan glaciation.
Summary(Plain Language Summary, not published)
This paper summarizes new research on the glacial history of the Smoking Hills, Northwest Territories, region. It provides a significant revision of previous glacial reconstructions, and is the first study to document evidence and provide an age for the earliest known continental glaciation in northwestern Canada (2.9 Ma). It identifies the preservation of "old" buried glacial ice at one site that pre-dates the last glaciation which is important in considerations of long-term permafrost stability in northern Canada. This research demonstrates that the area was fully glaciated during the last glaciation, something that has long been debated. Consequently, this research will strengthen emerging models of past glacial dynamics, which is important in consideration of regional mineral dispersal studies.

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