Nitrogen (N) is the most abundant element in Earth’s atmosphere, but is extremely depleted in the silicate Earth. However, it is not clear whether core sequestration or early atmospheric loss was responsible for this depletion. Here we study the effect of core formation on the inventory of nitrogen using laser-heated diamond anvil cells. We find that, due to the simultaneous dissolution of oxygen in the metal, N becomes much less siderophile (iron-loving) at pressures and temperatures up to 104 GPa and 5000 K, a thermodynamic condition relevant to the bottom of the magma ocean in the aftermath of the moon-forming giant impact. Using a core–mantle–atmosphere coevolution model, we show that the impact-induced processes (core formation and/or atmospheric loss) are unlikely to account for the observed N anomaly, which is instead best explained by the accretion of mainly N-poor impactors. The terrestrial volatile pattern requires severe N depletion on precursor bodies, prior to their accretion to the proto-Earth.

中文翻译：

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兆巴压力下核心的氮封存及其对陆地吸积的影响


氮 (N) 是地球大气中最丰富的元素，但在硅酸盐地球中却极度匮乏。然而，目前尚不清楚是否是岩心封存或早期大气损失造成了这种损耗。在这里，我们使用激光加热金刚石砧池研究核心形成对氮库存的影响。我们发现，由于金属中氧的同时溶解，在压力和温度高达 104 GPa 和 5000 K 的情况下，N 的亲铁性（亲铁性）大大降低，这是与岩浆海洋底部相关的热力学条件。形成月球的巨大撞击的后果。使用核心-地幔-大气共同演化模型，我们表明撞击引起的过程（核心形成和/或大气损失）不太可能解释观测到的氮异常，相反最好的解释是主要是贫氮的吸积冲击器。陆地挥发性模式要求前体天体在吸积到原地球之前发生严重的氮消耗。