基性麻粒岩半脆性域剪切带形成机制的实验研究  

EXPERIMENTAL STUDY OF MECHANISM FOR SEMI BRITTLE DUCTILE SHEAR ZONES IN MAFIC GRANULITE

作　　者：刘顺[1] 孙天泽[2] 钟大赉[3] 

机构地区：[1]成都理工学院地质学系 [2]中国科学院地球物理研究所 [3]中国科学院地质研究所

出　　处：《成都理工学院学报》1997年第3期36-41,共6页Journal of Chengdu University of Technology

基　　金：中国科学院地球动力学高温高压开放实验室资助;国家自然科学基金

摘　　要：在温度为８００～９００℃，围压为１ＧＰａ的条件下对基性麻粒岩进行了压缩变形实验。样品变形处于半脆性域，以出现非破裂的准韧性剪切带为特征。提出了剪切带是由样品的原始缺陷向外稳态扩展而形成的机制，可用稍加改变的流变介质断裂力学原理对这种扩展过程进行说明；并将此机制推广到剪切带的形成中。A mafic granulite from Shanxi Province, North China has been deformed at a confining pressure of 1 GPa and temperatures of 800￣900℃. Optical micrographs of deformed samples show that different scales of semi brittle ductile shear zones (SBDSZ) occur with different strains. A mechanism for the forming of SBDSZ, briefly to say, is to nucleate at pre existing weakness first and then to develop from this weakness steadily, which can be expressed by slightly revised theory of fracture mechanics of rheological materials. The experimental result is of significance in discussing the formation of ductile shear zones in the continental lower crust.

关 键 词：麻粒岩 剪切带 形成机制 实验研究 基性麻粒岩 

分 类 号：P588.346[天文地球—岩石学]