Thermal Diffusivity of Lherzolite at High Pressures and High Temperatures Using Pulse Method  

作　　者：Sheqiang Miao Yongsheng Zhou Heping Li 

机构地区：[1]State Key Laboratory of Earthquake Dynamics, Institute of geology,China Earthquake Administration [2]CAS Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences

出　　处：《Journal of Earth Science》2019年第1期218-222,共5页地球科学学刊（英文版）

基　　金：sponsored by the National Natural Science Foundation of China (No. 41504072);the "135" Program of Institute of Geochemistry, Chinese Academy of Sciences (CAS) and State Key Laboratory of Earthquake Dynamics

摘　　要：Lherzolite is one of the most important components of the subcontinental mantle lithosphere, and the study of its heat transfer properties aids in understanding the thermal structure of the continental mantle lithosphere. Currently, few studies have examined the heat transfer properties of lherzolite, and the experimental results remain controversial. This experiment utilized a pulse method to measure the thermal diffusivity of lherzolite at pressures ranging from 1.0 to 4.0 GPa and temperatures from 300 to 1 073 K on a cubic press apparatus. We obtained a thermal diffusivity for lherzolite of approximately 2.10 mm^2s^(-1) at ambient condition. The experimental pressure derivative of the thermal conductivity of lherzolite decreased with temperature, reaching approximately 10% at high temperature, a value higher than the previously reported 4%, which indicates that the temperature gradient of the upper mantle lithosphere is smaller than previously thought. Therefore, concerning calculation of the lithosphere thickness using the thermal conductivity of the lherzolite, the previous calculation using pressure derivative of the thermal conductivity of 4% may cause an underestimation of the upper mantle lithosphere thickness by approximately 6% in a first approximation.Lherzolite is one of the most important components of the subcontinental mantle lithosphere, and the study of its heat transfer properties aids in understanding the thermal structure of the continental mantle lithosphere. Currently, few studies have examined the heat transfer properties of lherzolite, and the experimental results remain controversial. This experiment utilized a pulse method to measure the thermal diffusivity of lherzolite at pressures ranging from 1.0 to 4.0 GPa and temperatures from 300 to 1 073 K on a cubic press apparatus. We obtained a thermal diffusivity for lherzolite of approximately 2.10 mm^2s^(-1) at ambient condition. The experimental pressure derivative of the thermal conductivity of lherzolite decreased with temperature, reaching approximately 10% at high temperature, a value higher than the previously reported 4%, which indicates that the temperature gradient of the upper mantle lithosphere is smaller than previously thought. Therefore, concerning calculation of the lithosphere thickness using the thermal conductivity of the lherzolite, the previous calculation using pressure derivative of the thermal conductivity of 4% may cause an underestimation of the upper mantle lithosphere thickness by approximately 6% in a first approximation.

关 键 词：THERMAL DIFFUSIVITY LHERZOLITE PULSE method PRESSURE DERIVATIVE 

分 类 号：P[天文地球]