大陆不稳定俯冲的动力学研究

发布时间：2018-05-01 09:30

本文选题：大陆不稳定俯冲 + 大陆稳定俯冲　；参考：《中国科学:地球科学》2017年02期

【摘要】：利用地球动力学数值模拟方法分析了大陆汇聚速率、地壳流变强度以及岩石圈热结构等三种主要动力学参数对大陆俯冲碰撞模式的影响和制约,并以此为基础,重点对大陆不稳定俯冲的发育条件、主要类型以及动力学演化过程进行探讨.模拟结果表明,有利于弱化大陆岩石圈流变强度的动力学条件,如低流变强度地壳、岩石圈高温热结构或低汇聚速率等,对大陆不稳定俯冲的形成均起到积极作用.根据俯冲大陆的动力学演化特征可将大陆不稳定俯冲概括为"多阶段断离"型、"持续性流入"型和"大规模拆沉"型等三种类型.这三种类型的发育分别与低汇聚速率、中-高速汇聚的大陆岩石圈高温热结构和低汇聚速率下的中等-高流变强度地壳有关.模拟结果也显示,大陆碰撞区域内岩石部分熔融的分布受地壳流变性质的显著影响.这些模拟结果为认知特定地球动力学背景下不同俯冲条件孕育的大陆俯冲格局具有意义.
[Abstract]:By using the geodynamic numerical simulation method, the influence and restriction of three main kinetic parameters, such as the continental convergence rate, the crustal rheology intensity and the lithosphere thermal structure, on the continental subduction and collision model are analyzed. On this basis, the development conditions, main types and dynamic evolution process of the continental unstable subduction are focused on. The simulation results show that the dynamic conditions for weakening the rheological strength of the continental lithosphere, such as the low rheological strength of the earth's crust, the high temperature thermal structure of the lithosphere or the low convergence rate, are all active in the formation of the unstable subduction of the continent. The three types of development are related to the low convergence rate, the high temperature thermal structure of the continental lithosphere and the medium high rheological strength at low convergence rate, respectively. The simulation results also show the distribution of partial melting of rocks in the continental collision region. The effects of the rheological properties of the earth's crust are significant. These results are significant for recognizing the continental subduction pattern of different subduction conditions under specific geodynamic background.

【作者单位】：中山大学地球科学与地质工程学院;中国科学院大学地球科学学院计算地球动力学实验室;中国科学院青藏高原研究所卓越研究中心;
【基金】：国家重点基础研究发展计划项目(编号:2014CB440901和2015CB856106) 重点研发计划专题项目(编号:2016YFC0600303) 国家自然科学基金项目(批准号:41190073和41372198) 中央组织部青年千人计划项目中山大学中央高校基本科研业务费专项资金资助
【分类号】：P541

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