裂历史对火山边缘形成的重要性
John J Armitage1, Jenny S Collier, Tim A Minshull
1Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, UK. j.armitage@imperial.ac.uk
Nature
|June 19, 2010
概括
大陆裂变和岩石流是相互关联的,但地幔温度不是唯一的驱动因素. 以前的延伸事件在大陆分裂期间显著影响了火山活动,解释了全球范围内的多样性岩.
科学领域:
- 地质地质地质地质地质地
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
背景情况:
- 裂变和岩石化是关键的地质过程,它们之间的关系对于理解行星表面演变至关重要.
- 以前,地幔温度被认为是大陆分裂期间岩产生的主要控制因素,主要基于北大西洋数据.
- 来自其他裂纹边缘的观测,比如印度洋西北部,挑战了这一观点,尽管与断裂事件有明显的联系,但显示出低质量.
研究的目的:
- 为了调和在断裂的大陆边缘的岩石运动的相互矛盾的观察.
- 调查过去的构造事件对当前裂期间的岩产生的影响.
- 开发一个数值模型,在不同的裂环境中比较岩.
主要方法:
- 应用数值模型来模拟裂变过程.
- 在模型中明确纳入早期地延伸事件的影响.
- 印度洋西北部和北大西洋边缘的岩石流的比较分析.
主要成果:
- 裂纹边缘的岩受地幔温度和延伸历史的控制.
- 之前的延伸事件可以显著抑制或增强在随后的裂纹过程中化的产生.
- 该模型成功地解释了在印度洋西北部边缘观察到的低磁性.
结论:
- 大陆的分解岩不仅仅取决于地幔温度.
- 遗传的延伸史是一个关键因素控制风格和体积的岩石在裂变期间.
- 这一发现解决了以前对全球裂边缘的岩变异的神秘观测.
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