00000nam 2200000zi 4500 9.902724 CaOODSP 20230131161140 m o d f cr mn||||||||| 210820t20222022oncab ob f000 0 eng d 9780660401195 CaOODSP eng rda CaOODSP eng eng fre n-cn-nt M44-2022/2E-PDF Fallas, K. M., author. Age dating of a bentonite in the Duo Lake Formation, western Mackenzie Mountains, Northwest Territories / K.M. Fallas and W. Matthews. [Ottawa] : Geological Survey of Canada, 2022. ©2022 1 online resource (14 pages) : illustrations (some colour), colour map. text txt rdacontent computer c rdamedia online resource cr rdacarrier Current research, 1701-4387 ; 2022-2 Includes bibliographical references (pages 12-14). "In 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"--Abstract, page 1. Includes abstracts in English and French. Bentonite Northwest Territories. Uranium-lead dating Northwest Territories. Bentonite Territoires du Nord-Ouest. Datation Méthode uranium-plomb Territoires du Nord-Ouest. Geological Survey of Canada, issuing body. Current research (Geological Survey of Canada) 2022-2. (CaOODSP)9.506236 PDF 22.18 MB https://publications.gc.ca/collections/collection_2022/rncan-nrcan/M44-2022-2-eng.pdf HTML N/A https://doi.org/10.4095/328830