Effects of thermal, compositional and rheological properties on the long-term evolution of large thermochemical piles of primordial material in the deep mantle

作     者：Min HUANG Yang LI Liang ZHAO 

作者机构：State Key Laboratory of Lithospheric EvolutionInstitute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519080China College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2022年第65卷第12期

页      面：2405-2416页

核心收录：

学科分类：0810[工学-信息与通信工程] 081801[工学-矿产普查与勘探] 081802[工学-地球探测与信息技术] 08[工学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0827[工学-核科学与技术] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41888101,41625016) the International Partnership Program of Chinese Academy of Sciences(Grant No.132A11KYSB20200019) the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.311021003) the Key Research Program of the Institute of Geology and Geophysics CAS(Grant No.IGGCAS-201904) the Pioneer Hundred Talents Program of Chinese Academy of Sciences 

主　　题：LLSVPs Primordial material Thermochemical piles Thermochemical structure of the deep mantle 

摘      要：Seismic tomography observations have shown that there are two large low shear velocity provinces(LLSVPs)above the core-mantle boundary beneath Africa and the *** thermal and compositional properties of these two LLSVPs may differ from those of the ambient mantle,and they are suggested to be thermochemical piles of primordial material in the lower *** evolution is of great importance to our understanding of mantle *** this study,we systematically conducted numerical experiments to investigate the effects of the buoyancy ratio(B),compositional viscosity ratio(Δη_(c)),and heat-producing ratio(Λ)of the primordial material on the long-term evolution of thermochemical *** results show that the buoyancy ratio plays the most important role in the stability of these *** the buoyancy ratio is small,and the primordial material is enriched in heat-producing elements(Λ1),the stability of these piles decreases with increasing compositional viscosity ratio or heat-producing *** cases with homogeneous heat production(Λ=1),the stability of these piles increases with increasingΔη*** further compare constant internal heating with radioactive decay internal heating,and find that the longterm stability of thermochemical piles slightly decreases with radioactive decay heating,but the overall differences between these two internal heating modes are relatively small.