总体非共轴持续变形产生的构造及其运动学意义——以金州韧性剪切带为例  

Structures formed during bulk non-coaxial progressive deformation and their kinematic significance:An example from Jinzhou ductile shear zone

作　　者：刘如琦 戴立军[1] 王铁军[1] 张鹏程[2] 

机构地区：[1]中钢集团天津地质研究院,天津300061 [2]中国黄金集团公司,北京100011

出　　处：《地质科学》2009年第3期825-835,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:49172135)资助

摘　　要：构造解析证实,金州韧性剪切带是以右行走滑为主的大型缓倾斜剪切带,带内发育的糜棱面理—小型褶皱—香肠构造及肿缩构造—S-C组构的系列,以及广泛分布的拉伸线理,是总体非共轴持续变形条件下,带内共轴与非共轴线路相结合的结果,并且后者占主要地位。糜棱面理是最早生成的透入性构造,对其他构造的形成有重要作用。剪应变量(γ)大小与糜棱岩化程度有直接关系。鞘褶皱多发育于γ≥10地段。微构造发育机制的变化是:γ由低到高,石英变形从低温晶体—塑性转向塑性变形与重结晶作用;而云母矿物从外形定向转向粘性颗粒—边界滑动。A detailed structural analysis of related planar and linear structures indicates that Jinzhou ductile shear zone was actually a gentle-dipping strike-slip shear zone with dextral sense of movement. Structural series of mylonitic foliation--minor folds--boudinage and pinch-and- swell structures--S-C fabrics together with extensively distributed stretching lineation in the belt was recognized to be the result of combination of two strain paths, the coaxial and the non- coaxial, with the latter occupying dominant position in the bulk non-coaxial progressive strain regime of the shear zone. Mylonitic foliation, the earliest planar structure, penetratively developed throughout the zone, played an important role in the formation of many other structures. The bulk of shear strain γ had a direct relationship with the extent of mylonitization. Sheath folds, the classic indicator for non-coaxial shear, were found in places where γ≥10. γ also led to changes of microstructural mechanisms： increasing of γ led to quartz deformation changing from low-temperature crystal-plasticity to plastic deformation and recrystallization,while mica minerals from shape orientation to viscous grain-boundary sliding.

关 键 词：非共轴持续变形 糜棱面理 金州韧性剪切带 微构造 糜棱岩化 

分 类 号：P542[天文地球—构造地质学]