气候变化领域集成服务门户(CCPortal): Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset

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DOI	10.1016/j.epsl.2020.116142
	Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset
	Hansen S.E.; Carson S.E.; Garnero E.J.; Rost S.; Yu S.
发表日期	2020
ISSN	0012821X
卷号	536
英文摘要	Given limited seismic coverage of the lowermost mantle, less than one-fifth of the core-mantle boundary (CMB) has been surveyed for the presence of ultra-low velocity zones (ULVZs). Investigations that sample the CMB with new geometries are therefore important to further our understanding of ULVZ origins and their potential connection to other deep Earth processes. Using core-reflected ScP waves recorded by the recently deployed Transantarctic Mountains Northern Network in Antarctica, the current study aims to expand ULVZ investigations in the southern hemisphere. Our dataset samples the CMB in the vicinity of New Zealand, providing coverage between an area to the northeast, where ULVZ structure has been previously identified, and another region to the south, where prior evidence for a ULVZ was inconclusive. This area is of particular interest because the data sample across the boundary of the Pacific Large Low Shear Velocity Province (LLSVP). The Weddell Sea region near Antarctica is also well sampled, providing new information on a region that has not been previously studied. A correlative scheme between a large database of 1-D synthetic seismograms and the observed ScP data demonstrates that ULVZs are required in both study regions. Modeling uncertainties limit our ability to definitively define ULVZ characteristics but also likely indicate more complex 3-D structure. Given that ULVZs are detected within, along the edge of, and far from the Pacific LLSVP, our results support the hypothesis that ULVZs are compositionally distinct from the surrounding mantle and are not solely related to partial melt. ULVZs may be ubiquitous along the CMB; however, they may be thinner in many regions than can be resolved by current methods. Mantle convection currents may sweep the ULVZs into thicker piles in some areas, pushing these anomalies toward the boundaries of LLSVPs. © 2020 The Author(s)
关键词	ScP southern hemisphere ultra-low velocity zones
英文关键词	Seismology; Structural geology; Uncertainty analysis; Velocity; Core-mantle boundary; Mantle convection; Model uncertainties; Seismic coverage; Shear velocities; Southern Hemisphere; Synthetic seismogram; Ultralow velocity zone; Shear flow; core-mantle boundary; data set; lower mantle; mantle convection; seismic data; seismic reflection; seismic velocity; seismicity; seismogram; Southern Hemisphere; Antarctica; New Zealand; Southern Ocean; Transantarctic Mountains; Weddell Sea
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202630
作者单位	Department of Geological Sciences, The University of Alabama, United States; School of Earth and Space Exploration, Arizona State University, United States; School of Earth and Environment, University of Leeds, Ireland
推荐引用方式 GB/T 7714	Hansen S.E.,Carson S.E.,Garnero E.J.,et al. Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset[J],2020,536.
APA	Hansen S.E.,Carson S.E.,Garnero E.J.,Rost S.,&Yu S..(2020).Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset.Earth and Planetary Science Letters,536.
MLA	Hansen S.E.,et al."Investigating ultra-low velocity zones in the southern hemisphere using an Antarctic dataset".Earth and Planetary Science Letters 536(2020).