气候变化领域集成服务门户(CCPortal): Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions

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DOI	10.1029/2019JB018560
	Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions
	Rajaonarison T.A.; Stamps D.S.; Fishwick S.; Brune S.; Glerum A.; Hu J.
发表日期	2020
ISSN	21699313
卷号	125 期号:2
英文摘要	Over the past few decades, azimuthal seismic anisotropy measurements have been widely used proxy to study past and present-day deformation of the lithosphere and to characterize convection in the mantle. Beneath continental regions, distinguishing between shallow and deep sources of anisotropy remains difficult due to poor depth constraints of measurements and a lack of regional-scale geodynamic modeling. Here, we constrain the sources of seismic anisotropy beneath Madagascar where a complex pattern cannot be explained by a single process such as absolute plate motion, global mantle flow, or geology. We test the hypotheses that either Edge-Driven Convection (EDC) or mantle flow derived from mantle wind interactions with lithospheric topography is the dominant source of anisotropy beneath Madagascar. We, therefore, simulate two sets of mantle convection models using regional-scale 3-D computational modeling. We then calculate Lattice Preferred Orientation that develops along pathlines of the mantle flow models and use them to calculate synthetic splitting parameters. Comparison of predicted with observed seismic anisotropy shows a good fit in northern and southern Madagascar for the EDC model, but the mantle wind case only fits well in northern Madagascar. This result suggests the dominant control of the measured anisotropy may be from EDC, but the role of localized fossil anisotropy in narrow shear zones cannot be ruled out in southern Madagascar. Our results suggest that the asthenosphere beneath northern and southern Madagascar is dominated by dislocation creep. Dislocation creep rheology may be dominant in the upper asthenosphere beneath other regions of continental lithosphere. ©2019. The Authors.
英文关键词	edge-driven convection; lattice preferred orientations; lithosphere-mantle wind interactions; mantle flow modeling; seismic anisotropy; splitting parameters
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/188002
作者单位	Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States; Department of Geology, University of Leicester, Leicester, United Kingdom; GFZ German Research Center of Geosciences, Potsdam, Germany; Institute of Earth and Environmental Sciences, University of Potsdam, Potsdam, Germany; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States
推荐引用方式 GB/T 7714	Rajaonarison T.A.,Stamps D.S.,Fishwick S.,et al. Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions[J],2020,125(2).
APA	Rajaonarison T.A.,Stamps D.S.,Fishwick S.,Brune S.,Glerum A.,&Hu J..(2020).Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions.Journal of Geophysical Research: Solid Earth,125(2).
MLA	Rajaonarison T.A.,et al."Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions".Journal of Geophysical Research: Solid Earth 125.2(2020).