俯冲的启动:通过添加水来增加关键性?
K Regenauer-Lieb1, D A Yuen, J Branlund
1Institute of Geophysics, Eidgenössische Technische Hochschule-Hönggerberg, Swiss Federal Institute of Technology, 8093 Zürich, Switzerland. klaus@tomo.ig.erdw.ethz.ch
概括
水在启动浮沉中发挥着关键作用,这是板块构造学中的一个基本过程. 数字模型表明,由沉积物负载驱动的水引起的热力学不稳定性,可以在数百万年内触发石层沉降.
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
- 地力学是什么?地力学是什么?
背景情况:
- 沉降是板块构造学中的一个关键过程,它负责将海洋石化层回收到地幔中.
- 引发潜水的精确机制仍然不太清楚,这阻碍了我们对板块构造进化的理解.
研究的目的:
- 为了研究水在引发潜水过程中的作用.
- 为了探索热力学不稳定性,驱动石灰岩层向地幔下流.
主要方法:
- 使用高分辨率的有限元模型 (分辨率<1公里).
- 将石化层的浮力学数据纳入模型中.
- 模拟了沉积物加载和水存在对石质层行为的影响.
主要成果:
- 固体-流体的热力学不稳定性是启动俯冲的必要条件.
- 沉积物负载可以在地质时间尺度 (约. 一亿年前).
- 水起滑剂的作用,促进双重反机制 (热弹性和热rheological) 驱动潜水.
结论:
- 水是引流开始的关键因素.
- 降温启动可能是一个缓慢的过程,由水滑促进的热和学反联合驱动.
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