Nitrogen Content in the Earth's Outer Core
Nitrogen Content in the Earth's Outer Core
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DOI：
10.1029/2018gl080555
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
S. Bajgain;M. Mookherjee;R. Dasgupta;D. Ghosh;B. Karki
中科院分区：
文献类型：
--
作者：
S. Bajgain;M. Mookherjee;R. Dasgupta;D. Ghosh;B. Karki
使用第一性原理分子动力学模拟，我们探索氮（N）的密度和声速的液态铁的影响，并评估其潜在的轻元素在地球的外核。我们的研究结果表明，Fe-N熔体不能同时解释地球外核的密度和地震速度。虽然约2.0重量% N可以解释外核的体声速，这样的N含量仅使液态Fe的密度降低~ 3%。与其他轻元素的速度和密度相匹配，将核心中的N限制在10.2wt.%。我们的发现表明，氮是地核中微量元素的一种，并且与地球化学质量平衡与陆地氮丰度和合金硅酸盐分配数据一致，这表明地核中不可能存在大量氮。
Using first principles molecular dynamic simulations, we explore the effects of nitrogen (N) on the density and sound velocity of liquid iron and evaluate its potential as a light element in the Earth's outer core. Our results suggest that Fe‐N melt cannot simultaneously explain the density and seismic velocity of the Earth's outer core. Although ~2.0 wt.% N can explain the bulk sound velocity of the outer core, such N content only lowers the density of liquid Fe by ~3%. Matching both the velocity and density by the other light elements limits the N in the core to ≪2.0 wt.%. Our finding suggests that nitrogen is a minor to trace element in the Earth's core and is consistent with the geochemical mass balance with terrestrial abundance of N and alloy‐silicate partitioning data, which suggest that there cannot be significant N in the core.