周期性不稳定性和克拉顿石化层的恢复
Lijun Liu1, Ling Chen1, Zebin Cao1
1State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
National science review
|March 6, 2025
概括
克拉托基根比周围的地幔更密集,挑战了传统的观点. 石层分层和再分层解释了大陆的升起和超大陆周期上的克拉顿演变.
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:
- 克拉顿是古老的大陆核心,传统上被认为是稳定的,这是由于浮力和强大的岩层根.
- 这种稳定性模型受到新的数据的挑战,这些数据表明更密集的岩根和动态过程.
研究的目的:
- 重新评估对kraton长寿负责的机制及其观察到的属性.
- 提出一个由超大陆周期驱动的岩石层演变的新模型.
主要方法:
- 审查现有的地质和地质物理研究.
- 对克拉顿石质层结构和密度的观测约束的分析.
- 石质层分层,再分层和表面提升过程的建模.
主要成果:
- 克拉顿根比环境地幔更密,热浮力仅部分抵消了组成密度.
- 一个中层石质层的不连续性促进了分层,然后再分层,导致显著的表面升高 (>1公里,>100 Myr).
- 这种动态过程比静态提升模型更好地与观测到的石层变形保持一致.
结论:
- 由超大陆周期驱动的重复分层-再分层循环的克拉托尼变形形成了当今的克拉托尼石化层.
- 这种机制解释了在大陆上观察到的长期地表升起和沉降模式.
- 这项研究表明了对cratonic进化和超大陆动态的新研究途径.
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