The origin of the terrestrial noble-gas signature
The origin of the terrestrial noble-gas signature
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DOI：
10.1038/nature11506
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发表时间：
2012-10
期刊：
影响因子：
64.8
通讯作者：
S. Shcheka;H. Keppler
中科院分区：
文献类型：
--
作者：
S. Shcheka;H. Keppler
与球粒陨石中的丰度相比，在地球和火星的大气中，氙的含量相对于氩而言明显减少。对于这种损耗的起源知之甚少，,,,,,,,,,。在这里，我们发现超过 1% 重量的氩可能溶解在 MgSiO3 钙钛矿（地球下地幔最丰富的相）中，而氙在 MgSiO3 钙钛矿中的溶解度要低几个数量级。因此，我们认为，在地球历史的早期阶段，钙钛矿从岩浆海洋中结晶出来，使氩集中在下地幔中。在大部分原始大气消失后，下地幔的脱气补充了大气中的氩和氪，但没有补充氙。我们的模型表明，氙相对于氩的消耗表明钙钛矿是从地球早期历史中的岩浆海洋中结晶出来的，也许还有火星。
In the atmospheres of Earth and Mars, xenon is strongly depleted relative to argon, when compared to the abundances in chondritic meteorites,. The origin of this depletion is poorly understood,,,,,,,,,,. Here we show that more than one weight per cent of argon may be dissolved in MgSiO3perovskite, the most abundant phase of Earth’s lower mantle, whereas the xenon solubility in MgSiO3perovskite is orders of magnitude lower. We therefore suggest that crystallization of perovskite from a magma ocean in the very early stages of Earth’s history concentrated argon in the lower mantle. After most of the primordial atmosphere had been lost, degassing of the lower mantle replenished argon and krypton, but not xenon, in the atmosphere. Our model implies that the depletion of xenon relative to argon indicates that perovskite crystallized from a magma ocean in the early history of Earth and perhaps also Mars.