Globally distributed subducted materials along the Earth's core-mantle boundary: Implications for ultralow velocity zones

被引：18

作者：

Hansen, Samantha E. ^{[1
]}

Garnero, Edward J. ^{[2
]}

Li, Mingming ^{[2
]}

Shim, Sang-Heon ^{[2
]}

Rost, Sebastian ^{[3
]}

机构：

[1] Univ Alabama, Dept Geol Sci, Tuscaloosa, AL 35487 USA

[2] Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ 85281 USA

[3] Univ Leeds, Sch Earth & Environm, Leeds LS2 9JT, England

来源：

SCIENCE ADVANCES | 2023年 / 9卷 / 14期

基金：

英国自然环境研究理事会;

关键词：

OCEANIC-CRUST; SEISMIC EVIDENCE; PARTIAL MELT; BASE; TEMPERATURE; IRON; CONSTRAINTS; SOLIDUS; PLUMES; MORB;

D O I：

10.1126/sciadv.add4838

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Ultralow velocity zones (ULVZs) are the most anomalous structures within the Earth's interior; however, given the wide range of associated characteristics (thickness and composition) reported by previous studies, the origins of ULVZs have been debated for decades. Using a recently developed seismic analysis approach, we find widespread, variable ULVZs along the core-mantle boundary (CMB) beneath a largely unsampled portion of the Southern Hemisphere. Our study region is not beneath current or recent subduction zones, but our mantle convection simulations demonstrate how heterogeneous accumulations of previously subducted materials could form on the CMB and explain our seismic observations. We further show that subducted materials can be globally distributed throughout the lowermost mantle with variable concentrations. These subducted materials, advected along the CMB, can provide an explanation for the distribution and range of reported ULVZ properties.

引用

页数：1