气候变化领域集成服务门户(CCPortal): U-Pb detrital zircon dating supports Early Jurassic initiation of the Cordilleran foreland basin in southwestern Canada

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DOI	10.1130/B31862.1
	U-Pb detrital zircon dating supports Early Jurassic initiation of the Cordilleran foreland basin in southwestern Canada
	Pană D.I.; Poulton T.P.; DuFrane S.A.
发表日期	2019
ISSN	167606
起始页码	318
结束页码	334
卷号	131 期号:2021-01-02
英文摘要	U-Pb geochronology of detrital zircon from Lower Jurassic to Lower Cretaceous strata of the southern Canadian Rocky Mountains fold-and-thrust belt documents the presence of zircon ages close to the time of sediment accumulation throughout this succession. The identification of syndepositional zircons in Lower Jurassic strata indicates proximity of Cordilleran island arcs and terranes to the Western Canada epicratonic basin, consistent with the Jurassic sudden appearance of ash layers in the basin stratigraphy. The association of syndepositional zircon grains with Paleozoic arc-related zircons and zircons in the "North American Magmatic Gap"-likely derived from the Mesoproterozoic Belt-Purcell Supergroup-hints at possible geographic connections to the west or southwest since Early Jurassic, long before the inferred Kimmeridgian initiation of the ancestral Rocky Mountain foredeep trough in the region. Paleozoic and older grains in the Jurassic strata reflect the pre-history of the basin distributive province and show an episodic pattern that includes well-defined lower Paleozoic and Grenvillian maxima, and early Neo- to Paleoproterozoic populations, which may reflect recycling of detrital zircons from older clastic formations uplifted in the Cordilleran orogen. The youngest peaks in the probability diagrams provide maximum depositional ages for several imprecisely dated stratigraphic units. Discordant data modeling suggests a Pb-loss event in the Early Cretaceous (ca. 125-115 Ma). Our provenance data and the Fernie stratigraphic record suggest initiation of Jurassic deposition either in the backbulge or the distal foredeep depozones. We propose two alternative Jurassic foreland basin evolutionary models that explain the Fernie stratigraphic record in the examined epicratonic southwestern Canada as the result of vertical stacking of migrating foreland depozones, east of the encroaching Cordilleran orogen. The two possible initial settings, backbulge or distal foredeep, require either normal cratonward migration of a forebulge or cratonward migration interrupted by a Callovian phase of orogenward retreat, respectively. Besides filling a long-standing knowledge gap, our data allow direct comparison between the southern Canada and northern United States segments of the Cordilleran foreland basin. © 2018 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184974
作者单位	Alberta Geological Survey/Alberta Energy Regulator, 402, Twin Atria Building, 4999 - 98 Avenue, Edmonton, AB T6B 2X3, Canada; Geological Survey of Canada, 3303 33 Street Northwest, Calgary, AB T2L 2A7, Canada; University of Alberta, Department of Earth and Atmospheric Sciences, 1-26 Earth Sciences Building, Edmonton, AB T6G 2E3, Canada
推荐引用方式 GB/T 7714	Pană D.I.,Poulton T.P.,DuFrane S.A.. U-Pb detrital zircon dating supports Early Jurassic initiation of the Cordilleran foreland basin in southwestern Canada[J],2019,131(2021-01-02).
APA	Pană D.I.,Poulton T.P.,&DuFrane S.A..(2019).U-Pb detrital zircon dating supports Early Jurassic initiation of the Cordilleran foreland basin in southwestern Canada.Bulletin of the Geological Society of America,131(2021-01-02).
MLA	Pană D.I.,et al."U-Pb detrital zircon dating supports Early Jurassic initiation of the Cordilleran foreland basin in southwestern Canada".Bulletin of the Geological Society of America 131.2021-01-02(2019).