High Pressure Experiments on Metal‐Silicate Partitioning of Chlorine in a Magma Ocean: Implications for Terrestrial Chlorine Depletion
High Pressure Experiments on Metal‐Silicate Partitioning of Chlorine in a Magma Ocean: Implications for Terrestrial Chlorine Depletion
复制标题
岩浆海洋中氯的金属硅酸盐分配的高压实验：对陆地氯消耗的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
S. Sugita
中科院分区：
文献类型：
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作者：
H. Kuwahara;H. Gotou;T. Shinmei;N. Ogawa;A. Yamaguchi;N. Takahata;Y. Sano;T. Yagi;S. Sugita
在大块硅酸盐地球中，氯比其他具有类似挥发性的元素更加枯竭；然而，陆地氯枯竭的原因并不是很清楚。有两个主要的假说被提出来解释这种损耗：并入地球的金属核心和逃逸到太空。前一种假设可以通过研究氯在富铁金属液体和硅酸盐熔体之间的分配来检验。在这项研究中，我们研究了在4到23 Gpa的压力和1,650到2,400°C的温度下，氯在富铁金属液体和硅酸盐熔体之间的实验分配。结果表明，在实验条件下，氯具有中等到高度的亲石性。在无硫实验中，随着温度的升高，氯变得更亲铁，而随着压力的增加，亲铁变得更少。对于含硫实验，没有观察到压力或温度的显著影响。基于这些数据和热力学考虑，我们得到了估算富铁金属液体和硅酸盐熔体之间氯分配系数的经验定律。在P-T条件下，在地球岩心分凝过程中控制金属-硅酸盐平衡的情况下，计算的金属-硅酸盐对氯的分配系数远低于1。这一结果表明，可能存在于吸积地球中的陆地氯没有被分割到其核心，支持逃逸到太空的假设更有可能。如果陆地上的氯被遗失到太空，那么氯的耗竭可能是由于地球形成过程中原始水圈的丧失造成的。
In the bulk silicate Earth, chlorine is more depleted than other elements with similar volatilities; however, the cause of terrestrial chlorine depletion is not well understood. Two major hypotheses have been proposed to explain this depletion: Incorporation into the Earth's metallic core and escape to space. The former hypothesis can be tested by investigating the partitioning of chlorine between iron‐rich metallic liquids and silicate melts. In this study, we investigated the experimental partitioning of chlorine between iron‐rich metallic liquids and silicate melts at pressures from 4 to 23 GPa and temperatures from 1,650 to 2,400°C using multi‐anvil presses. The results demonstrate that chlorine is moderately to highly lithophile under the experimental conditions. In sulfur‐free experiments, chlorine becomes slightly more siderophile as temperature increases and less siderophile as pressure increases. For sulfur‐bearing experiments, no significant effects of pressure or temperature were observed. Based on these data and thermodynamic considerations, we obtained empirical laws to estimate chlorine partition coefficients between iron‐rich metallic liquids and silicate melts. Under the P‐T conditions that would have controlled metal‐silicate equilibration during core segregation in the Earth, the calculated metal‐silicate partition coefficients for chlorine are much lower than unity. This result suggests that terrestrial chlorine that may have been present in the accreting Earth was not partitioned into its core, supporting that escape to space is the more likely hypothesis. If terrestrial chlorine was lost to space, chlorine depletion may have resulted from the loss of the primordial hydrosphere during the formation of the Earth.
DOI：
10.1098/rsta.2008.0147
发表时间：
2008-11-28
影响因子：
5
作者：
Frost, D. J.;Mann, U.;Rubie, D. C.
通讯作者：
Rubie, D. C.
影响因子：
3.5
作者：
Jochum, Klaus Peter;Stoll, Brigitte;Woodhead, Jon D.
通讯作者：
Woodhead, Jon D.