气候变化领域集成服务门户(CCPortal): Laramide Orogenesis Driven by Late Cretaceous Weakening of the North American Lithosphere

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DOI	10.1029/2020JB019570
	Laramide Orogenesis Driven by Late Cretaceous Weakening of the North American Lithosphere
	Saylor J.E.; Rudolph K.W.; Sundell K.E.; van Wijk J.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	This paper investigates the causes of the Late Cretaceous transition from “Sevier” to “Laramide” orogenesis and the spatial and temporal evolution of effective elastic thickness (EET) of the North American lithosphere. We use a Monte Carlo flexural model applied to 34 stratigraphic profiles in the Laramide province and five profiles from the Western Canadian Basin to estimate model parameters which produce flexural profiles that match observed sedimentary thicknesses. Sediment thicknesses come from basins from New Mexico to Canada of Cenomanian–Eocene age that are related to both Sevier and Laramide crustal loads. Flexural models reveal an east-to-west spatial decrease in EET in all time intervals analyzed. This spatial decrease in EET may have been associated with either bending stresses associated with the Sevier thrust belt, or increased proximity to attenuated continental crust at the paleocontinental margin. In the Laramide province (i.e., south of ~48°N) there was a coeval, regional decrease in EET between the Cenomanian–Santonian (~98–84 Ma) and the Campanian–Maastrichtian (~77–66 Ma), followed by a minor decrease between the Maastrichtian and Paleogene. However, there was no decrease in EET in the Western Canada Basin (north of ~48°N), which is consistent with a lack of Laramide-style deformation or flat subduction. We conclude that the regional lithospheric weakening in the late Santonian–Campanian is best explained by hydration of the North American lithosphere thinned by bulldozing by a shallowly subducting Farallon plate. The weakening of the lithosphere facilitated Laramide contractional deformation by focusing end-loading stresses associated with flat subduction. Laramide deformation in turn may have further reduced EET by weakening the upper crust. Finally, estimates of Campanian–Maastrichtian and Paleogene EET are comparable to current estimates indicating that the modern distribution of lithospheric strength was achieved by the Campanian in response to flat subduction. ©2020. The Authors.
英文关键词	flat Subduction; flexural modeling; flexure; Monte Carlo; rheology
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187690
作者单位	Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada; Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, United States; Department of Geosciences, University of Arizona, Tucson, AZ, United States; Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM, United States
推荐引用方式 GB/T 7714	Saylor J.E.,Rudolph K.W.,Sundell K.E.,et al. Laramide Orogenesis Driven by Late Cretaceous Weakening of the North American Lithosphere[J],2020,125(8).
APA	Saylor J.E.,Rudolph K.W.,Sundell K.E.,&van Wijk J..(2020).Laramide Orogenesis Driven by Late Cretaceous Weakening of the North American Lithosphere.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Saylor J.E.,et al."Laramide Orogenesis Driven by Late Cretaceous Weakening of the North American Lithosphere".Journal of Geophysical Research: Solid Earth 125.8(2020).