自哈迪纪以来,地球地幔的恒定氧化状态
Fangyi Zhang1, Vincenzo Stagno2, Lipeng Zhang3,4
1Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China. zhangfy@qdio.ac.cn.
Nature communications
|August 10, 2024
概括
地幔氧气流动性 (fo2) 在阿纪时期较低,但随着时间的推移由于世俗冷却而增加. 这导致了更深的融化,融化中的FO2更高,并导致大气氧化.
科学领域:
- 地质化学 地质化学
- 地质物理学 地质物理学
- 行星科学 行星科学
背景情况:
- 地幔氧气流动性 (fo2) 的演变对于理解地幔衍生的融化物和大气组成至关重要.
- 以前关于地幔FO2进化的研究已经产生了有争议的结果.
- 由地幔衍生的融物,包括科马提和皮克里特,为深层地球过程提供了洞察力.
研究的目的:
- 通过时间来研究地幔热和氧化还原状态的演变.
- 分析从3.8亿年前到现在的羽毛衍生和环境地幔衍生化的综合数据集.
- 为了确定地幔氧气流失的长期趋势.
主要方法:
- 编制和分析一个全面的数据集的komatiites,picrites,和 (meta) basalts.
- 地质化学分析以确定古代地幔衍生的化的氧气流动性 (fo2).
- 将fo2标准化为恒定的参考压力 (潜在的氧气流动性),以考虑融深度的变化.
主要成果:
- 地板衍生的融化物 (风和环境) 在阿尔开纪期间表现出较低的FO2比阿尔开纪后.
- 随着时间的推移,地幔衍生融化的fo2的增加与地幔潜在温度和融化深度的下降相关.
- 自哈迪纪以来,潜在的氧气流动性一直相对不变,这表明深层地幔的氧化还原条件稳定.
结论:
- 地球地幔的长期冷却已经减少了地质时间的融化深度.
- 降低融深度增加了地幔衍生的融的氧气流动性 (fo2).
- 这一过程可能有助于地球大气层的逐渐氧化.
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