威尔逊周期在 3 亿年开始,由亚大陆地幔的钻石显示
Steven B Shirey1, Stephen H Richardson
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA. shirey@dtm.ciw.edu
概括
钻石中的矿物质含量揭示了大约30亿年前地球地幔的主要组成变化. 这种变化,从石石到生态石的钻石,意味着板块构造学的早期出现.
科学领域:
- 地质化学 地质化学
- 矿物学是什么?矿物学是什么?
- 构造学 构造学 构造学 构造学
背景情况:
- 钻石中的矿物质含量是地球地幔的原始样本,提供了对其历史的见解.
- 这些含量提供了关键的年龄和化学数据,跨越了35亿年,包括大陆生长和大气演变.
研究的目的:
- 分析钻石中酸盐和硫化物含有物的同位素和散装化学数据.
- 为了确定地球地幔在地质时间上的组成变化.
主要方法:
- 从矿物质含量中汇编同位素和散装化学数据.
- 对钻石构成的分析,特别是石和生态石类型.
主要成果:
- 大约在30亿年前 (Ga) 确定了形成钻石的地幔的显著组成变化.
- 在3.2亿年前,只有石钻石形成;此后,生态石钻石成为主导.
结论:
- 转向生态石质钻石的转变表明,被压缩的海洋地被纳入了次大陆地幔.
- 这一事件与潜伏和大陆碰撞有关,可能标志着板块构造学和威尔逊周期的开始.
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