近日，法国巴黎城市大学 Felix Vayrac团队报道了太古宙石英的地幔地球动力学和大气逸出记录。2025年11月7日出版的《科学进展》杂志发表了这项成果。

早期的行星脱气和大气逃逸是塑造早期地球的两个主要但不受限制的过程。模型预测大气中²⁰Ne/²²Ne的比值对太阳-Ne地幔在地质时期的脱气非常敏感。在大氧化事件之前，大气逸出逐渐耗尽了大气中的Xe，留下了同位素印记。然而，古代大气中氙的含量在很大程度上仍然未知。

研究组对太古宙热液石英流体中的稀有气体进行了分析，发现现代大气中²⁰Ne/²²Ne的比值在2.7 Ga以前几乎达到了，这意味着在地球历史的前17亿年里，地幔脱气非常强烈，比今天高出3个数量级。此外，研究组确定了太古代大气的Xe/Kr比，比今天高2.3倍，与大气逃逸的Xe耗竭模型一致。

附：英文原文

Title: Records of mantle geodynamics and atmospheric escape in Archean quartz

Author: Félix Vayrac, Guillaume Avice, Xinmu J. Zhang, Rita Parai, Pascal Philippot

Issue&Volume: 2025-11-07

Abstract: Early planetary degassing and atmospheric escape are two major, yet unconstrained, processes that shaped early Earth. Modeling predicts that the atmospheric 20Ne/22Ne ratio is sensitive to solar-Ne mantle degassing over geological time. Until the Great Oxidation Event, atmospheric escape progressively depletes the atmosphere in Xe, leaving an isotopic imprint. However, the quantity of xenon in the ancient atmosphere remains largely unknown. In this study, we analyzed noble gases in Archean hydrothermal quartz fluid inclusions and show that a modern atmospheric 20Ne/22Ne ratio was almost reached 2.7 Ga ago, implying intense mantle degassing during the first 1.7 billion years of Earth’s history, three orders of magnitude higher than today. Furthermore, we determine an Archean atmospheric Xe/Kr ratio, 2.3 times higher than today, consistent with models of Xe depletion over time through atmospheric escape.

DOI: aea3380

Source: https://www.science.org/doi/10.1126/sciadv.aea3380