Morphology and possible origins of the Perm anomaly in the lowermost mantle of Earth  

作　　者：YuMei He LianXing Wen Yann Capdeville 

机构地区：[1]Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]Mohe Observatory of Geophysics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [3]Laboratory of Seismology and Physics of Earth’s Interior,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China [4]Department of Geosciences,State University of New York at Stony Brook,Stony Brook,New York,USA [5]Laboratoire de Planétologie et Géodynamique de Nantes,UMR6112,CNRS,Universitéde Nantes,Nantes,France

出　　处：《Earth and Planetary Physics》2021年第1期105-116,共12页地球与行星物理（英文版）

基　　金：the National Natural Science Foundation of China(grant 41474042);the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(IGGCAS);grant IGGCAS-201904;the Computer Simulation Lab,IGGCAS and NSF(grants 0911319 and 1214215).

摘　　要：We have constrained a small-scale,dome-shaped low-velocity structure near the core-mantle boundary(CMB)of Earth beneath Perm(the Perm anomaly)using travel-time analysis and three-dimensional(3-D)forward waveform modeling of seismic data sampling of the mantle.The best-fitting dome-shaped model centers at 60.0°E,50.5°N,and has a height of 400 km and a radius that increases from 200 km at the top to 450 km at the CMB.Its velocity reduction varies from 0%at the top to–3.0%at 240km above the CMB to–3.5%at the CMB.A surrounding 240-km-thick high-velocity D''structure has also been detected.The Perm anomaly may represent a stable smallscale chemical pile in the lowermost mantle,although the hypothesis of a developing mantle plume cannot be ruled out.

关 键 词：seismic velocity structure core-mantle boundary Perm anomaly chemical pile 

分 类 号：P542.5[天文地球—构造地质学]