大陆下地壳麻粒岩的流变学研究进展

Deformation Mechanism and Rheological Property of Granulite in the Continental Lower Crust:A Review

大陆下地壳麻粒岩的流变学研究可以解释地壳变形、壳幔物质交换以及岩石圈深部动力学过程等科学问题。前人通过研究各矿物的显微构造变形特征与变形机制,运用广义混合流变律探讨多矿物复合岩石的流变性质,结合水与流体对岩石变形强度的弱化作用,阐明在大陆下地壳变形环境下复矿麻粒岩的塑性变形和韧性流变性质。目前人们致力于对天然变形岩石和实验变形矿物的高温高压实验研究,通过实验室模拟大陆下地壳变形条件下岩石矿物的变形、熔融过程,探讨大陆下地壳复矿麻粒岩流变学特征。大陆下地壳麻粒岩流变学研究在宏观和微观构造上存在着密切的联系,以青藏高原下地壳流动与麻粒岩高温塑性流变的关系为例,阐述区域构造(造山带深部物质的挤出)与大陆下地壳流变学的关系及其制约因素研究的进展。复矿麻粒岩流变学研究是探讨大陆下地壳流动变形和变形强度的科学基础,由于该项研究在国内外开展时间还不算长,许多科学问题尚待深入研究。

The rheological study of granulite from continental lower crust is one of the scientific problems,which reveals the crustal deformation,crust-mantle exchange,and deep lithosphere dynamic process.This paper integrates the previous work on microstructure and deformation mechanisms of multiphase granulite,and clarifies the plastical deformation mechanism and rheological properties of multiphase granulite under the deformation conditions of lower continental crust by the application of generalized mixed flow law and combining the effect of water weakening or fluid on the deformation strength of the lower crust.At present,researchers are working on the high-temperature and high-pressure deformation experiments of natural and experimental deformed minerals,and explore the rheological property of multiphase granulite in the continental lower crust by means of experimental simulation of the process of mineral deformation and melting under the lower continental crust condition.There is a very close relationship between the macroscopic and microscopic structure study of rheological study of lower continental crust granulite.This paper introduces research progress of the rheological relationship between regional tectonics（the extrusion of material beneath the orogenic belt） and lower continental crust flow and their controlling factors,taking the example of the relationship between lower crustal flow from Tibet plateau and the high temperature plastic rheology of granulite under continental lower crust.The rheological study of multiphase granulite is the scientific basis for discussion on the continental lower crust deformation and its strength.Since the time of the study carried out in China and abroad is not too long,many scientific issues are still need further study.