韧性剪切带的变形分域现象——以辽东的丹东韧性剪切带为例  

DEFORMATION PARTITIONING IN DUCTILE SHEAR ZONES——AN EXAMPLE FROM THE DANDONG DUCTILE SHEAR ZONE

作　　者：刘如琦 戴立军[1] 王铁军[1] 崔武军[1] 杨秀峰[1] 

机构地区：[1]中钢集团天津地质研究院,天津300061

出　　处：《地质科学》2007年第2期223-233,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金资助项目(批准号:49172135)

摘　　要：丹东韧性剪切带的实例表明:韧性剪切带的持续变形包含了共轴与非共轴两种应变线路或状态,由于分布的不均匀性,导致变形分域现象,形成平面的变形岩石分区。持续变形过程中,又存在应变线路的转换和叠加。微构造是确定变形体制的主要依据。野外观测与应变分析证实,变形分域存在于不同尺度,在总体剪切(非共轴)变形条件下,初始糜棱岩往往表现以共轴变形占优势,而糜棱岩和超糜棱岩则以非共轴变形为主。持续变形导致从共轴向非共轴转变,最后形成后者的主体地位。Recent works on structural analysis of the Dandong ductile shear zone indicated that in terms of path description, both of the coaxial and non-coaxial deformations were involved in the progressive deformation within the shear zone. Moreover, spatially random distribution of the path types gave rise to deformation partitioning, and accordingly, subdivision of deformed rocks in plan. There was also an alteration of strain path during progressive deformation. The microstructures should be one of the most important tools for analysis of deformation regime. The field observation and strain analysis confirmed further that the deformation partitioning took place on different scales within the ductile shear zone, under bulk shear strain （non-coaxial） regime, coaxial deformation always preponderantly occurred in protomylonite, whereas in mylonite and uhramylonite, the non-coaxial type dominated. Progressive deformation led to an evolution from coaxial to non-coaxial strain, with the dominant position of the latter throughout the shear zone ultimately.

关 键 词：变形分域 持续变形 微构造 有限应变 丹东韧性剪切带 

分 类 号：P542[天文地球—构造地质学]