变形角闪质岩石流动变形及其意义——以辽东古元古宙褶皱带变形斜长角闪岩为例

Flow and Deformation Mechanisms of Hornblende Rocks——Example of Deformed Amphibolites from the Paleoproterozoic Fold Belt in Liaodong Peninsula

通过显微和亚微分析揭示出辽东地区3种变形特点的角闪质岩石(片麻状斜长角闪岩、条带状斜长角闪岩和糜棱状斜长角闪岩)具有差异的显微及亚微构造。通过地质温压计计算,3种斜长角闪岩及其原岩的形成与变形温压条件具有从升温升压经降温升压到降温降压的变化规律(片麻状斜长角闪岩:597.0℃,0.536 GPa;条带状斜长角闪岩:617.3℃,0.455 GPa;糜棱状斜长角闪岩:558.8℃,0.514 GPa)。从其趋势和规律,结合显微构造分析,3种岩石是同一期变形不同阶段的产物。在递进变形作用过程中,塑性变形是斜长角闪岩流动和蠕变的主要机制。结合前人的实验变形结果,修正了大陆岩石圈结构模型。

Microstructural studies of three types of tectonites from eastern Liaoning area with diffe-rent deformation characteristics（gneissic,banded and mylonitic structures） by means of microstructural analysis,transmission electron microscope（TEM） analysis shows us they have different microstructures and submicrostructures.Through geothermometry and geobarometry,the temperature and pressure conditions of the three types of amphibolites are calculated,gneissic amphibolites： 597.0 ℃,0.536 GPa,banded amphibolites： 617.3 ℃,0.455 GPa,mylonitic amphibolites： 558.8 ℃,0.514 GPa.From the trend of variation of temperatures and pressures and in combination of microstructural analysis of three types of tectonites,it is suggested that they are formed and deformed at different stages in the same episode of deformation and metamorphism.In combination with experiments data,the dynamic and rheological structure of the lithosphere is discussed.