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Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
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在没有热点轨迹的情况下,绝对板块运动和真正的极地流浪
Bernhard Steinberger1, Trond H Torsvik
1Centre for Geodynamics, Geological Survey of Norway, Leiv Eirikssons vei 39, 7491 Trondheim, Norway. bernhard.steinberger@ngu.no
Nature
|April 4, 2008
概括
这项研究区分了真正的极地流浪和3200万年来的板块运动. 它揭示了不同的旋转事件,表明了长期的地质稳定性和地幔过程的新参考框架.
科学领域:
- 地质物理学 地质物理学
- 板块构造学是一种板块构造学.
- 古磁力学是一种古磁学.
背景情况:
- 与地球旋转轴相对的大陆运动可能是由于真正的极地漫游或单个板块运动而产生的.
- 区分这些运动对于理解长期的地球动态至关重要.
- 3,2亿年前庞盖亚超大陆的形成提供了一个关键的时间框架.
研究的目的:
- 为了区分真正的极地流浪与过去3200万年的板块运动.
- 在古磁参考框架内计算全球平均大陆运动和旋转.
- 建立一个新的参考框架,用于表层和深层地幔的相关工艺.
主要方法:
- 使用古磁数据计算了全球平均大陆运动和旋转.
- 分析了自庞盖亚形成以来的过去3200万年的数据.
- 确定了稳定向北运动和明显的旋转事件的组成部分.
主要成果:
- 确定了稳定的北向大陆漂移和重大真正的极地流浪事件.
- 记录了反时钟旋转 (250-220亿年前) 和时钟旋转 (195-145亿年前) 在未来三重交点附近的特定轴周围.
- 观测到进一步的旋转 (145-135万年前和110-100万年前) 在北非/阿拉伯的一个轴周围,与地质极值相关联.
结论:
- 确定的旋转为真正的极地流浪事件提供了证据.
- 在3200万年中近于零的净旋转表明了长期的地质和地幔结构稳定性.
- 为地幔过程研究提出了一个新的基于古磁学的参考框架,对真正的极地漫游进行了校正.
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