Effect of iron content on thermal conductivity of ferropericlase: implications for planetary mantle dynamics.
Effect of iron content on thermal conductivity of ferropericlase: implications for planetary mantle dynamics.
复制标题
铁含量对方镁石热导率的影响：对行星地幔动力学的影响。
DOI：
10.1029/2022gl101769
复制
发表时间：
2023
影响因子：
5.2
通讯作者：
M. Osako
中科院分区：
文献类型：
--
作者：
Y. Zhang;T. Yoshino;M. Osako
我们通过脉冲加热方法同时测量了不同 Fe 含量（Fp3、Fp5、Fp10、Fp20、Fp30 和 Fp50）的多晶方镁石的热导率 (λ) 和热扩散率 (κ)，最高可达 23 GPa 和 1100 K。实验结果表明，即使方镁石中含有少量的铁，与氧化镁方镁石相比，在低温下的导热系数也会大幅降低数倍。随着方镁石中Fe的增加，它们对压力和温度的依赖性均减小。与硅酸盐相比，含Fe方镁石的λ对温度不敏感，并且随着温度的升高呈现先增大后减小的趋势。推导了估算地幔条件下任意组成的方镁石铁酶λ的通用方程。富铁方镁石酶的低λ值可以解释超低速区的一种可能起源。这项研究表明，方镁石中的铁含量是控制类地行星冷却历史的重要因素。
We have simultaneously measured thermal conductivity (λ) and thermal diffusivity (κ) for polycrystalline ferropericlase with different Fe contents (Fp3, Fp5, Fp10, Fp20, Fp30and Fp50) up to 23 GPa and 1100 K by a pulse heating method. Experiment results reveals that even small amounts of Fe in ferropericlase can strongly reduce the thermal conductivity by several times at low temperature compared with MgO periclase. With increasing Fe in ferropericlase, both their pressure and temperature dependence decrease.λof Fe‐bearing ferropericlase is not sensitive to temperature compared with silicates and shows a tendency of first increasing and then decreasing with increasing temperature. A universal equation was derived to estimateλof ferropericlase with arbitrary composition under mantle conditions. The lowλvalues of Fe‐rich ferropericlase can explain one possible origin of ultralow velocity zones. This study suggests that Fe content in ferropericlase is an important factor controlling the cooling history of terrestrial planets.