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TitleHolocene lake-level recession, permafrost aggradation and lithalsa formation in the Yellowknife area, Great Slave Lowland
AuthorWolfe, S A; Morse, P D
SourceProceedings of GEOQuebec 2015 - Canadian Permafrost Conference; 2015 p. 1-8
Year2015
Alt SeriesEarth Sciences Sector, Contribution Series 20150084
PublisherCanadian Geotechnical Society
MeetingGeoQuebec 2015: Challenges from North to South; with 7th Canadian Permafrost Conference; Quebec, QC; CA; September 20-23, 2015
Documentbook
Lang.English
Mediapaper; digital
File formatpdf (Adobe® Reader®)
ProvinceNorthwest Territories
NTS85I; 85J; 85K; 85N; 85O; 85P
AreaYellowknife; Great Slave Lake; Yellowknife River
Lat/Long WENS-117.5000 -113.0000 63.7500 62.0000
Subjectssurficial geology/geomorphology; environmental geology; geochronology; geochemistry; Nature and Environment; Science and Technology; Holocene; glacial lakes; surface waters; lakes; water levels; glacial history; deglaciation; emergence; permafrost; ground ice; periglacial features; organic deposits; peatlands; clays; sands; silts; soils; organic materials; alluvial plains; mass spectrometer analysis; radiometric dating; radiocarbon dating; isotopic studies; oxygen isotopes; Great Slave Lowland; Glacial Lake McConnell; Ancestral Great Slave Lake; Laurentide Ice Sheet; lithalsas; aggradation; glaciolacustrine sediments; lacustrine sediments; alluvial sediments; landscape evolution; elevations; Phanerozoic; Cenozoic; Quaternary
Illustrationsgeoscientific sketch maps; photographs; tables; lithologic sections; plots; stratigraphic charts; frequency distribution diagrams
ProgramLand-based Infrastructure, Climate Change Geoscience
Released2015 01 01
AbstractThe Great Slave Lowland occupies the north shore of Great Slave Lake. After glaciation, it was inundated by Glacial Lake McConnell and ancestral Great Slave Lake. Holocene lake-level recession around Yellowknife is determined from accelerator mass spectrometer ages of peat and detrital organics. In the last 8000 years, recession occurred at about 5 mm/year, and permafrost is youngest near the modern shoreline and older at higher elevations. Silty-clay sediments are abundant, and lithalsas (ice-rich permafrost mounds within mineral soils) occurring within 40 m above the present lake level are less than 6000 years old. They are common on Yellowknife River alluvium deposited within the last 3000 years. Lithalsas on this surface are assumed to have developed as permafrost aggraded into saturated sediments, and ground ice has formed within the last 250 years.
Summary(Plain Language Summary, not published)
The Great Slave Lowland occupies the north shore of Great Slave Lake. After glaciation, it was inundated by glacial Lake McConnell and ancestral Great Slave Lake. Holocene lake-level recession around Yellowknife is determined from accelerator mass spectrometer ages from peat and detrital organics. In the last 8000 years, recession occurred at about 5 mm/year, and permafrost is youngest near the modern shoreline and older at higher elevations. Silty-clay sediments are abundant, and lithalsas (ice-rich permafrost mounds) occurring within 40 m above the present lake level are less than 6000 years old. They are common on Yellowknife River alluvium deposited within the last 3000 years. Lithalsas on this surface probably developed as permafrost aggraded into saturated sediments, and ground ice has formed within the last 250 years.
GEOSCAN ID296563