气候变化领域集成服务门户(CCPortal): Joint Local and Teleseismic Tomography in the Central United States: Exploring the Mantle Below the Upper Mississippi Embayment and the Illinois Basin

CCPortal

DOI	10.1029/2020JB020625
	Joint Local and Teleseismic Tomography in the Central United States: Exploring the Mantle Below the Upper Mississippi Embayment and the Illinois Basin
	Geng Y.; Powell C.A.; Saxena A.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Three-dimensional, high-resolution crustal and upper mantle P and S wave velocity (Vp and Vs) models are presented for the central United States using body wave tomography. The study utilizes local and teleseismic data recorded by the Northern Embayment Lithospheric Experiment stations, the CERI New Madrid Seismic Network, the Earthscope Transportable Array, and the Ozark Illinois INdiana Kentucky Flexible Array. Vp and Vs solutions are very similar and are well resolved in the depth range 40 to 400 km. Two anomalously slow regions are present below the Illinois Basin, forming a northwest dipping low-velocity zone (LVZ) extending from ~200 to 400 km. Maximum anomaly magnitudes in the LVZ reach about −4% and −5% for Vp and Vs, respectively. The LVZ appears to connect to a well-documented LVZ located below the northern Mississippi Embayment. The Illinois Basin velocity anomalies cannot be explained by elevated temperature alone and require compositional heterogeneity involving elevated orthopyroxene content in addition to an increase in iron and water content. The need for additional orthopyroxene suggests that the LVZ is being produced by metasomatism of mantle rocks by hydrous, silica-rich fluids ascending from a slab fragment trapped in or near the transition zone. This supports previous interpretations for the existence of the LVZ below the Embayment. We suggest that the LVZs below the Mississippi Embayment and the Illinois Basin are linked to the presence of a large igneous province, which convection models suggest is currently located below the central United States. ©2020. American Geophysical Union. All Rights Reserved.
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/187582
作者单位	Center for Earthquake Research and Information, University of Memphis, Memphis, TN, United States; Department of Geological Sciences, University of Florida, Gainesville, FL, United States
推荐引用方式 GB/T 7714	Geng Y.,Powell C.A.,Saxena A.. Joint Local and Teleseismic Tomography in the Central United States: Exploring the Mantle Below the Upper Mississippi Embayment and the Illinois Basin[J],2020,125(10).
APA	Geng Y.,Powell C.A.,&Saxena A..(2020).Joint Local and Teleseismic Tomography in the Central United States: Exploring the Mantle Below the Upper Mississippi Embayment and the Illinois Basin.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Geng Y.,et al."Joint Local and Teleseismic Tomography in the Central United States: Exploring the Mantle Below the Upper Mississippi Embayment and the Illinois Basin".Journal of Geophysical Research: Solid Earth 125.10(2020).