气候变化领域集成服务门户(CCPortal): Long-Wavelength Gravity Field Constraint on the Lower Mantle Viscosity in North America

CCPortal

DOI	10.1029/2020JB020484
	Long-Wavelength Gravity Field Constraint on the Lower Mantle Viscosity in North America
	Reusen J.M.; Root B.C.; Szwillus W.; Fullea J.; van der Wal W.
发表日期	2020
ISSN	21699313
卷号	125 期号:12
英文摘要	The long-wavelength negative gravity anomaly over Hudson Bay coincides with the area depressed by the Laurentide Ice Sheet during the Last Glacial Maximum, suggesting that it is, at least partly, caused by glacial isostatic adjustment (GIA). Additional contributions to the static gravity field stem from surface dynamic topography, core-mantle boundary (CMB) topography, and density anomalies in the subsurface. Previous estimates of the contribution of GIA to the gravity anomaly range from 25% to more than 80%. However, these estimates did not include uncertainties in all components that contribute to the gravity field. In this study, we develop a forward model for the gravity anomaly based on density models and dynamic models, investigating uncertainty in all components. We derive lithospheric densities from equilibrium constraints but extend the concept of lithospheric isostasy to a force balance that includes the dynamic models. The largest uncertainty in the predicted gravity anomaly is due to the lower mantle viscosity, uncertainties in the ice history, the crustal model, the lithosphere-asthenosphere boundary, and the conversion from seismic velocities to density have a smaller effect. A preference for lower mantle viscosities >1022 Pa s is found, in which case at least 60% of the observed long-wavelength gravity anomaly can be attributed to GIA. This lower bound on the lower mantle viscosity has implications for inferences based on models for mantle convection and GIA. ©2020. The Authors.
英文关键词	glacial isostatic adjustment; gravity modeling; Hudson Bay; mantle viscosity
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/187475
作者单位	Astrodynamics & Space Missions, Delft University of Technology, Delft, Netherlands; Department of Geosciences, Kiel University, Kiel, Germany; School of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin, Ireland; Department Fsica Tierra y Astrofsica, Universidad Complutense de Madrid, Madrid, Spain
推荐引用方式 GB/T 7714	Reusen J.M.,Root B.C.,Szwillus W.,et al. Long-Wavelength Gravity Field Constraint on the Lower Mantle Viscosity in North America[J],2020,125(12).
APA	Reusen J.M.,Root B.C.,Szwillus W.,Fullea J.,&van der Wal W..(2020).Long-Wavelength Gravity Field Constraint on the Lower Mantle Viscosity in North America.Journal of Geophysical Research: Solid Earth,125(12).
MLA	Reusen J.M.,et al."Long-Wavelength Gravity Field Constraint on the Lower Mantle Viscosity in North America".Journal of Geophysical Research: Solid Earth 125.12(2020).