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TitleAge dating of a bentonite in the Duo Lake Formation, western Mackenzie Mountains, Northwest Territories
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorFallas, K MORCID logo; Matthews, WORCID logo
SourceGeological Survey of Canada, Current Research (Online) 2022-2, 2022, 14 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Mediaon-line; digital
RelatedNRCan photo(s) in this publication
File formatpdf
ProvinceNorthwest Territories; Yukon
NTS105O/06; 105O/07; 105O/08; 105O/09; 105O/10; 105O/11; 105O/12; 105O/13; 105O/14; 105O/15; 105O/16; 105P/05; 105P/06; 105P/07; 105P/10; 105P/11; 105P/12; 105P/13; 105P/14; 105P/15; 106A/02; 106A/03; 106A/04; 106A/05; 106A/06; 106A/07; 106A/11; 106A/12; 106B; 106C/01; 106C/02; 106C/07; 106C/08; 106C/09; 106C/10; 106C/15; 106C/16; 106F/01; 106F/02; 106G/02; 106G/03; 106G/04
AreaMackenzie Mountains
Lat/Long WENS-133.0000 -128.5000 65.2500 63.2500
Subjectsgeochronology; paleontology; stratigraphy; tectonics; Science and Technology; Nature and Environment; radiometric dating; uranium lead dating; bentonite; zircon; argon argon dating; bedrock geology; lithology; sedimentary rocks; shales; igneous rocks; volcanic rocks; depositional history; fossils; tectonic history; volcanism; biostratigraphy; Duo Lake Formation; Misty Creek Embayment; Marmot Formation; Graptolites; Phanerozoic; Paleozoic; Silurian; Ordovician
Illustrationslocation maps; geoscientific sketch maps; stratigraphic charts; photographs; tables; photomicrographs; plots; Concordia diagrams; stratigraphic columns
ProgramGEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination
Released2022 03 24
AbstractIn the Misty Creek Embayment of the western Mackenzie Mountains, Duo Lake Formation locally includes minor volcanic deposits associated with Marmot Formation volcanism. A bentonite layer from an outcrop of graptolitic shale found in NTS map area 106-B, in the upper part of the Duo Lake Formation, was sampled for U-Pb zircon dating. Analytical results yielded a dominant population of grains with a concordia age of 439.8 ± 3.0 Ma, interpreted as the age of deposition. Minor inherited zircon populations yielded ages ranging from approximately 1200 to 2850 Ma. Observed graptolites from the same outcrop likely range from Middle Ordovician to Early Silurian and are compatible with the interpreted U-Pb age of the bentonite. Previously known Middle and Late Ordovician volcanic activity in the Misty Creek Embayment is here expanded to include Early Silurian activity, and serves as a proxy for the timing of active extensional tectonism in the basin.
Summary(Plain Language Summary, not published)
This paper provides the results of age dating of an outcrop of Duo Lake Formation in the Backbone Ranges of the Mackenzie Mountains, Northwest Territories. Material dated includes zircon grains from a layer of bentonite (volcanic ash) interbedded with shale. These grains were dated using U-Pb geochronology. Fossilized graptolites from the same outcrop were also documented for comparison between the fossil age and the zircon age. The zircon age from the bentonite is the first reported age of this type in this unit and provides an important constraint on the age of the unit and timing of volcanic activity.

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