双板停滞深度由谷粒大小诱导的零星低粘度区域控制,在约1000公里深处
Jing Li1, Keqing Li1, Jiangtao Li2
1Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, China.
Nature communications
|March 3, 2026
概括
数字模型显示,局部低粘度区域 (LVZs) 解释了为什么构造板在660公里或1000公里深处停滞不前. 这些区域是由谷粒大小的减少形成的,在那里古老的板块沉入了超过660公里的不连续性.
科学领域:
- 地质物理学 地质物理学
- 矿物物理 矿物物理
- 构造学 构造学 构造学 构造学
背景情况:
- 地震断层扫描表明,构造板块在大约660公里和1000公里深处在地球地幔内停滞不前.
- 目前还没有一个统一的机制来解释这两个不同深度的板块停滞.
研究的目的:
- 调查对构造板块停滞深度的控制因素.
- 探索谷粒大小演变和局部低粘度区 (LVZs) 在板块行为中的作用.
主要方法:
- 利用了包含自相一致的谷粒大小演变跟踪的数值模型.
- 在沟退缩和LVZ存在的不同条件下,模拟了地幔动态和板块行为.
主要成果:
- 化石板块可以触发穿越660公里不连续性的地幔下沉.
- 在660公里处的相位过渡会导致颗粒大小的减少,在660至1000公里之间形成LVZ.
- 弱停滞深度取决于沟撤退速度和LVZ的存在:用LVZ缓慢撤退导致1000公里的停滞,而快速撤退或没有LVZ导致660公里的停滞或更深的透.
结论:
- 零星的LVZ为观察到的双板停滞深度提供了一个机制.
- 沉没的化石板块可以创建横向异质的中间地幔粘度结构.
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