在钻石中的coesite中保存的极端地氧同位素签名
Daniel J Schulze1, Ben Harte, John W Valley
1Department of Geology, University of Toronto, Erindale College, Mississauga, Ontario, Canada L5L 1C6. dschulze@credit.erin.utoronto.ca
Nature
|May 2, 2003
概括
古老的海底变化的生态石异石提供了大陆进化的证据. 来自钻石中的coesite包含的新氧同位素数据支持这种联系,加强了克拉顿稳定模型.
科学领域:
- 地质化学 地质化学
- 石化学 石化学是一门学科.
- 同位素地质学的同位素.
背景情况:
- 来自cratonic上层地幔的eclogite xenoliths显示异常的氧同位素值,表明古代海底的变化.
- 这一观测支持了大陆进化的模型,其中涉及到海底的海洋石化层,稳定了早期的石坑.
- 之前的研究发现了小的同位素异常,阻碍了对生态石的接受,将其视为变形的海底玄武岩.
研究的目的:
- 为了研究在生态石异石中含有的矿物质含量的氧同位素组成.
- 为了提供更强有力的证据,改变了海洋底基岩和地幔生态岩之间的遗传联系.
- 为了解决氧同位素异常之间的异常和已知的改变基岩石之间的异常.
主要方法:
- 在钻石中的coesite含量中对氧同位素组成的现场分析.
- 使用离子微探针/二次离子质谱仪进行精确的同位素测量.
- 将coesite包含的氧同位素值与潜水区元岩和岩的氧同位素值进行比较.
主要成果:
- 发现coesite含有物的氧同位素值大大高于以前报告的亚地层地幔石.
- 这些高氧同位素值是潜水区元基岩的典型特征.
- 这些发现表明,改变的海底玄武岩和地幔生态石异岩之间存在显著的联系.
结论:
- 这项研究提供了强有力的支持,即eclogite xenoliths起源于变形,改变了海洋底基岩的假设.
- 新的数据协调了观察到的氧同位素异常,加强了克拉顿形成和稳定模型.
- 这项研究增强了我们对早期地生长和地地相互作用在地球历史上的理解.
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