Core-Mantle Co-Evolution - An Interdisciplinary Approach
Core-Mantle Co-Evolution - An Interdisciplinary Approach
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核-幔共同演化——跨学科方法
DOI：
10.1002/9781119526919.ch12
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Davies C
中科院分区：
文献类型：
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作者：
Davies C
热化学相互作用 核幔边界（CMB）的中子在确定地球深部内部的动力学和演化方面起着不可或缺的作用。这篇评论考虑了在CMB的热量和质量传递所产生的核心过程，特别关注热化学分层和氧化物的沉淀。一个基本参数是核心的热导率，我们估计为W mKat CMB条件的基础上一致的外推，从最近的一些研究。这些高电导率值意味着早期基底岩浆海洋（BMO）的存在，覆盖在热核心上，快速冷却可能导致发电机在内部核心形成之前就失去了动力，即所谓的“新核心悖论”。耦合核心热演化模型和计算之间的化学平衡液态铁和硅酸盐熔体表明，FeO从BMO溶解到核心后，其形成，创造一个稳定分层的化学层下面的CMB，而沉淀的MgO和Siwas推迟到最后Gyrs，因此无法提供动力的早期发电机，但是，一旦启动，沉淀提供了充足的电力场发电。我们还提出了一个可能的解决方案，新的核心悖论，而不需要沉淀或放射性加热usingWmK。该模型与现今的内核大小和对流地幔顶部的热流和温度相匹配。它预测了现今的CMB热流为8.5 TW，化学稳定层厚100 km，BMO寿命为2 Gyrs。
Thermo‐chemical interactio ns at the core‐mantle boundary (CMB) play an integral role in determining the dynamics and evolution of Earth's deep interior. This review considers the processes in the core that arise from heat and mass transfer at the CMB, with particular focus on thermo‐chemical stratification and the precipitation of oxides. A fundamental parameter is the thermal conductivity of the core, which we estimate asW mKat CMB conditions based on consistent extrapolation from a number of recent studies. These high conductivity values imply the existence of an early basal magma ocean (BMO) overlying a hot core and rapid cooling potentially leading to a loss of power to the dynamo before the inner core formed aroundGyrs ago, the so‐called “new core paradox.” Coupling core thermal evolution modeling and calculations of chemical equilibrium between liquid iron and silicate melts suggests that FeO dissolved from the BMO into the core after its formation, creating a stably stratified chemical layer below the CMB, while precipitation of MgO and Siwas delayed until the lastGyrs and was therefore not available to power the early dynamo; however, once initiated, precipitation supplied ample power for field generation. We also present a possible solution to the new core paradox without requiring precipitation or radiogenic heating usingW mK. The model matches the present inner core size and heat flow and temperature at the top of the convecting mantle. It predicts a present‐day CMB heat flow of 8.5 TW, a chemically stable layer 100 km thick, and a BMO lifetime of 2 Gyrs.