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Fluid processes in subduction zones: two-phase flow numerical simulation and observational constraints

俯冲带流体过程：两相流数值模拟和观测约束

基本信息

批准号：
72476102
负责人：
Professor Dr. Harro Schmeling
金额：
--
依托单位：
Graduate School of Science and Engineering / Earth and Planetary Sciences
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2008
资助国家：
德国
起止时间：
2007-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/72476102?language=en
关键词：
Fluid processes subduction zones two

项目摘要

Subduction zones are places of intense mass exchange between the Earth’s surface and its interior, and consequently are associated with extensive volcanism and earthquakes. Geophysical fluids, especially water, are deeply involved in this exchange process but the physics underlying the fluid transport from the dehydrating subducting lithosphere to the surface is still matter of debate. Indeed, several modes of transportation (dykes, diapirs, Darcy-type percolation) have been suggested but their degree of implication has still to be determined. The two-phase flow theory in its new formulation (Bercovici and Ricard 2003) is used to investigate the consequence of water exsolution and percolation on the dynamics of the surrounding matrix (subducting lithosphere and mantle wedge). In the first phase of the project an appropriate 2D code (fluid & rocky matrix) including compaction with variable bulk viscosity has been developed, and a semi-analytical new solution of a solitary porosity wave has been found to benchmark such codes. After including the energy equation and poro-viscoelasticity numerical models will be carried out in a 2D geometry adapted to subduction zone settings. The effect of matrix compaction and water exsolution on the mantle wedge dynamics and thus on the arc-magma generation and water recycling into the deep mantle will be studied. The cooperation partner Prof. H. Iwamori of the Tokyo Institute of Technology will provide his expertise on subduction zone petrology and focus on water effects on phase change thermodynamics. Numerical results will be compared to the available seismic and petrological data, especially from the Japanese arc.

俯冲带是地球表面和内部之间进行强烈质量交换的地方，因此与广泛的火山活动和地震有关。地球物理流体，特别是水，深深地参与了这种交换过程，但流体从脱水的俯冲岩石圈向地表输送的物理基础仍然存在争议。事实上，已经提出了几种运输方式(堤坝、底辟、达西型渗流)，但它们的影响程度仍有待确定。采用新的两相流理论(Bercovici和Ricard 2003)研究了水的析出和渗流对周围基质(俯冲岩石圈和地幔楔体)动力学的影响。在项目的第一阶段，已经开发了一个适当的2D程序(流体和岩石矩阵)，其中包括变体积粘性压实，并找到了一个孤立孔隙率波的半解析新解来作为基准。在包含能量方程和多孔粘弹性之后，将在适应俯冲带环境的2D几何结构中进行数值模型。将研究基质压实和水的出溶对地幔楔形动力学的影响，从而对弧岩浆的产生和水进入地幔深部的循环的影响。合作伙伴东京工业大学的H.Iwamori教授将提供他在俯冲带岩石学方面的专业知识，并专注于水对相变热力学的影响。数值结果将与现有的地震和岩石学数据进行比较，特别是来自日本弧区的数据。