Electrical and thermal conductivity of Earth's core and its thermal evolution——A review  

作　　者：Yuan Yin Qingwen Zhang Youjun Zhang Shuangmeng Zhai Yun Liu 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,550081,China [2]International Research Center for Planetary Science,College of Earth Sciences,Chengdu University of Technology,Chengdu,610059,China [3]Institute of Atomic and Molecular Physics,Sichuan University,Chengdu,610065,China [4]Key Laboratory of High-Temperature and High-Pressure Study of the Earth’s Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,550081,China

出　　处：《Acta Geochimica》2022年第4期665-688,共24页地球化学学报（英文）

基　　金：financial support from the National Natural Science Foundation of China(Grant Nos.41804082 and 41873073);the Special Research Assistant Funding Program provided by the Chinese Academy of Sciences。

摘　　要：The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly correlated to geodynamo.Here we review a large number of studies on the electrical and thermal conductivity of iron and iron alloys and discuss their implications on the thermal evolution of the Earth’s core.In summary,we suggest that the Wiedemann-Franz law,commonly used to convert the electrical resistivity to thermal conductivity for metals and alloys,should be cautiously applied under extremely high pressure-temperature(P-T)conditions(e.g.,Earth’s core)because the Lorentz number may be P-T dependent.To date,the discrepancy in the thermal conductivity of iron and iron alloys remains between those from the resistivity measurements and the thermal diffusivity modeling,where the former is systematically larger.Recent studies reconcile the electrical resistivity by first-principles calculation and direct measurements,and this is a good start in resolving this discrepancy.Due to an overall higher thermal conductivity than previously thought,the inner core age is presently constrained at~1.0 Ga.However,light elements in the core would likely lower the thermal conductivity and prolong the crystallization of the inner core.Meanwhile,whether thermal convection can power the dynamo before the inner core formation depends on the amounts of the proper light elements in the core.More works are needed to establish the thermal evolution model of the core.

关 键 词：Earth’s core Electrical and thermal conductivity Iron and its alloys Thermal evolution GEODYNAMO 

分 类 号：P542.5[天文地球—构造地质学]