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TitleCambrian detrital zircon signatures of the northern Cordilleran passive margin, Liard area, Canada: evidence of sediment recycling, non-Laurentian ultimate sources, and basement denudation
AuthorMcMechan, M; Currie, L; Ferri, F; Matthews, W; O'Sullivan, P
SourceCanadian Journal of Earth Sciences vol. 54, issue 6, 2017 p. 609-621, https://doi.org/10.1139/cjes-2016-0127
Year2017
Alt SeriesEarth Sciences Sector, Contribution Series 20160262
PublisherNRC Research Press
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceYukon; British Columbia; Alberta; Northwest Territories
AreaLiard Area
Lat/Long WENS-128.0000 -115.0000 62.0000 59.0000
Subjectsgeochronology; uranium lead dates; uranium lead dating; zircon dates; source rocks; Vizer Formation; Mount Roosevelt Formation; Liard Line
Illustrationslocation maps; geological sketch maps; stratigraphic correlations; tables; histograms; graphs
ProgramShale Reservoir Characterization, Geoscience for New Energy Supply (GNES)
AbstractDetrital zircon U-Pb age probability distributions for the Cambrian Vizer formation (informal) and middle member of the Mount Roosevelt Formation of the northern Canadian Cordilleran miogeocline indicate extensive recycling from ~1.7 to 1.6 Ga Paleoproterozoic sandstones with no detectable first cycle input from Laurentian basement. The Vizer formation contains North American Magmatic Gap (1610 to1490 Ma) detrital zircons and lacks ultimate Grenvillian sourced grains. An ultimate non-Laurentian source is indicated and the grains were mostly likely sourced from a nearby Mesoproterozoic basin. Detrital zircon U-Pb ages of 690 to 640 Ma from the middle member of the Mount Roosevelt Formation indicate associated volcanic clasts were locally sourced, and are not of syn-sedimentary Middle Cambrian age. Provenance of these units was indirectly impacted by the Liard Line basement feature.
Detrital zircon U-Pb age probability distributions from the northern Canadian Cordilleran miogeocline indicate significant variations in source areas occurred during the Early and Middle Cambrian. Source areas changed from the east in the Early Cambrian (Terreneuvian; Vizer formation and correlatives) to northeast during Early Cambrian (Series 2) deposition of Sekwi Formation and correlative strata. In the early Middle Cambrian the middle member of the Mount Roosevelt Formation was locally sourced from the east, west and north, whereas the upper member was derived from Laurentian basement to the east and southeast. The change from reworked Paleoproterozoic cover in the Terrenuvian to primary basement sources in the Middle Cambrian suggests significant denudation of the basement occurred east of the northern miogeocline.
Summary(Plain Language Summary, not published)
Detrital zircons have been used to show the changes in source areas for Cambrian strata in part of northwestern Canada. Although most grains are recycled from older sediments some of the grains originally came from Australian and not North American sources. Changes in source areas also suggest more erosion and exposure of the basement occurred with time.
GEOSCAN ID299420