硫酸盐在雪球后地球海洋的起源:河流输入与架衍生的H2S
Huiming Bao1,2, Yongbo Peng1,2, Xiaobin Cao1,2
1International Center for Isotope Effects Research, Nanjing University, China.
National science review
|November 18, 2024
概括
从6.35亿年前的全球巴里特硫酸盐同位素数据挑战了大气氧气的河硫酸盐假设. 货架上的水性H2S氧化模型是一个有希望的替代方案,需要进一步的科学验证.
科学领域:
- 地质化学 地质化学
- 古气候学 古气候学
- 同位素地质学的同位素.
背景情况:
- 新新生态时代,特别是6.35亿年前全球冰川的结束,见证了大气和海洋的重大变化.
- 这一时期大气中独特的17O贫氧 (O2) 标志一直是科学研究的焦点.
- 以前的假设表明,河硫酸盐是这种独特的同位素特征的主要载体.
研究的目的:
- 用全球酸硫酸盐同位素数据重新评估17O贫大气O2签名的来源.
- 为了测试当前的假设,即河流硫酸盐输入对观察到的大气同位素组成负责.
- 探索可以解释同位素异常的替代地质化学模型.
主要方法:
- 从大约6.35亿年前的全球酸硫酸盐同位素数据的编译和合成.
- 在巴里特样本中分析氧和硫同位素比率 (δ18O, δ34S).
- 同位素数据与来自不同地质化学模型的预测进行比较.
主要成果:
- 合成的巴里特硫酸盐同位素数据不支持河硫酸盐是17O贫大气O2的主要来源的假设.
- 同位素组成表明,除了河流之外的硫酸盐来源占主导地位.
- 一种涉及大陆架上含有硫化 (H2S) 氧化的替代模型为观察到的同位素特征提供了更令人信服的解释.
结论:
- 传统的河硫酸盐假设17O贫大气O2签名被新的同位素证据所破坏.
- 大陆架上的水性H2S氧化被认为是产生这种大气特征的重要,替代途径.
- 在多个科学领域对H2S氧化模型的广泛验证对其接受至关重要.
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