北大西洋中古时代北大西洋裂变的动态与欧洲板块内部变形有关
Søren B Nielsen1, Randell Stephenson, Erik Thomsen
1Department of Earth Science, University of Aarhus, Høegh-Guldbergsgade 2, DK-8000 Aarhus C, Denmark. sbn@geo.au.dk
Nature
|December 14, 2007
概括
大陆的分裂导致了6200万年前欧洲板块变形的转变. 这项研究将北大西洋裂变与板内部应力变化联系在一起,驳斥了地幔羽毛理论.
科学领域:
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
- 地球科学 地球科学 地球科学
背景情况:
- 大陆的分裂为板块构造学和深层地幔动态提供了洞察力.
- 板块运动重建缺乏关于事件时间和动态的详细信息.
- 板内部变形记录了板边界过程带来的应力变化.
研究的目的:
- 为了证明北大西洋大陆裂变和欧洲板内部变形之间的因果关系.
- 调查压力变化在大陆分裂中的作用.
- 改进对板块运动学之外的构造事件时间的理解.
主要方法:
- 对应应力变化的板内变形风格的分析.
- 地质事件与板块构造重建的相关性.
- 从板块边界转移到大陆内部的应力转移的建模.
主要成果:
- 发现北大西洋裂变 (约62万年前) 和欧洲板内部变形的变化之间存在因果关系.
- 北大西洋裂变暂停了欧洲和非洲之间的融合.
- 在欧洲,收缩性板内变形停止,并被应力放松取代.
- 破裂前的构造压力,而不是地幔羽毛,可能推动了大陆的分裂.
结论:
- 大陆的分裂直接与板内应力变化有关.
- 洲际层级记录为构造事件提供了关键的时间和动态信息.
- 板块构造学,而不是地幔羽毛,可以驱动大陆的分裂,并影响深层地幔的动态.
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