Influence of Thermal Stratification on the Structure and Evolution of the Martian Core
Influence of Thermal Stratification on the Structure and Evolution of the Martian Core
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DOI：
10.1029/2021gl095198
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发表时间：
2021-11-28
影响因子：
5.2
通讯作者：
Pommier, Anne
中科院分区：
文献类型：
--
作者：
Greenwood, Sam;Davies, Christopher J.;Pommier, Anne
火星内部产生的磁场在3.6-4.1Ga处明显结束，这是火星历史上的一个关键事件，与核心冷却不足有关。我们使用参数化模型研究了火星核和地幔的热演化和磁演化，并在以往研究的基础上考虑了三个改进。首先，我们的模型考虑了地心的热分层。其次，这些模型受到对当今地区的估计的限制。第三，我们考虑了最近在火星核心条件下对铁合金进行的实验所建议的核心热导率Kc在5-40Wm(-1)K-1范围内的值。我们的大多数模型表明，目前火星的核心是完全导电的，核心温度大于1940K。所有的模型都符合k(C)=16-35Wm(-1)K-1的范围。活化体体积为6(0)cm(3)摩尔(-1)的模型需要地幔参考粘度为10(19)-10(20)(10(20)-10(21))PaS。
The apparent end of the internally generated Martian magnetic field at 3.6-4.1 Ga is a key event in Martian history and has been linked to insufficient core cooling. We investigate the thermal and magnetic evolution of the Martian core and mantle using parameterized models and considered three improvements on previous studies. First, our models account for thermal stratification in the core. Second, the models are constrained by estimates for the present-day areotherm. Third, we consider core thermal conductivity, kc, values in the range 5-40 W m(-1) K-1 as suggested by recent experiments on iron alloys at Mars core conditions. The majority of our models indicate that the core of Mars is fully conductive at present with core temperatures greater than 1940 K. All of our models are consistent with the range of k(c)=16-35 W m(-1) K-1. Models with an activation volume of 6 (0) cm(3) mol(-1) require a mantle reference viscosity of 10(19)-10(20)(10(20)-10(21)) Pa s.