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TitleDetrital zircon U-Pb geochronology of upper Devonian and lower Carboniferous strata of western Laurentia (North America): a record of transition from passive to convergent margin
AuthorHedhli, M; Hadlari, TORCID logo; Grasby, SORCID logo; Beauchamp, B; Alonso-Torres, D; Matthews, W A
SourceLithosphere 9585729, 2022 p. 1-18, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20210703
Mediapaper; on-line; digital
File formatpdf; html
AreaCanada; United States of America
Lat/Long WENS-171.3342 -104.3169 70.0458 28.6783
Subjectsgeochronology; Science and Technology; Nature and Environment; zircon; uranium lead dating; Laurentia; Carboniferous; Devonian
Illustrationslocation maps; diagrams; charts
ProgramEnergy Geoscience Geothermal Energy
Released2022 06 20
AbstractThe Late Devonian-Early Carboniferous (DC) Antler orogeny in southwestern Laurentia is contemporaneous with influx of clastic sediments, unconformities, and volcanism across much of western Laurentia (WL), suggesting the demise of the Paleozoic passive margin. However beyond the type Antler orogeny in southwestern Laurentia, the DC tectonic setting is still unclear. Westerly sediment provenance has been suggested as evidence of a convergent margin setting in a foreland basin. However, there is a gap in our understanding in central WL (Alberta and Montana) despite the fact that paleogeographic reconstructions place this area at the centre of WL. We provide detrital zircon (DZ) U-Pb geochronological data from strata in Alberta, Montana, and Nevada that are synchronous with the Antler orogeny to constrain sediment dispersal patterns and test the westerly sediment sourcing hypothesis. We show three DZ facies specific to particular geographic locations: DZ facies 1 in southern Nevada has a prominent subpopulation of early to mid-Mesoproterozoic (mode at 1430 Ma), DZ facies 2 in northeastern Nevada has a late Paleoproterozoic population (mode at 1823 Ma), and DZ facies 3 in Alberta and Montana displays Mesoproterozoic to Neoproterozoic (mode at 1036 Ma), mid-Paleozoic (mode at 411 Ma), and depositional (ca. 360-340 Ma) ages. North-south variation in DZ facies indicates that WL basins were locally sourced from various tectonic fragments having different signatures. Comparing our data with published data, we show that WL is dominated by DZ recycled from uplifted older strata with input from mid-Paleozoic arc terrane (s) to the west. Westerly sourcing is evidenced by the presence of near-depositional ages and affinities of this study's DZ facies with strata located to the west. Our results and geological evidence from other studies suggest that the Antler orogeny triggered a depositional shift and controlled sediments dispersal in WL, signaling the demise of the Paleozoic passive margin.
Summary(Plain Language Summary, not published)
The clastic sediments of western Canada represent a recycling of Cambrian clastics that are derived from the crystalline basement of North America. in general the clastic rocks of western Canada are recognized for their wealth in natural resources. They host major reservoirs and act as hot water aquifer in the subsurface. Studying the provenance of the Paleozoic clastics of western Canada and link them to their original source allows us to better understand reservoir types and distribution for potential geothermal use.

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