Role of Water in Deformed Omphacite in UHP Eclogite from the Dabie Mountains,Eastern China  

作　　者：SUWen YOUZhendong CONGBolin YEKai 

机构地区：[1]LaboratoryofLithosphereTectonicEvolution,InstituteofGeologyandGeophysics,ChineseAcademyofSciences,Beijing100029 [2]ChinaUniversityofGeosciences,Wuhan,Hubei430074

出　　处：《Acta Geologica Sinica(English Edition)》2003年第3期320-325,共6页地质学报（英文版）

基　　金：funded by the Ministry of Science and Technology of China(No.G19990755-01);the National Natural Science Foundation of China,Postdoctoral Science Foundation of China,the Chinese Academy of Sciences Wong K.C.Post-doctoral Research Award Fund and the State Key Laboratory of Mineral Deposits,Nanjing University

摘　　要：Omphacite grains from UHP eclogite of the Dabie Mountains in eastern China are elongated and show strong lattice preferred orientations (LPOs). Observations by the transmission electron microscopy (TEM) identified not only structures of plastic deformation occurring as free dislocation, dislocation loops and dislocation walls, but also bubbles of water present in the deformed omphacite. The bubbles attach to the dislocation loops which are often connected to one another via a common bubble. Using infrared spectroscopy (IR), two types of hydrous components are identified as hydroxyl and free-water in the omphacite. An analysis of deformation mechanism of microstructure in omphacite suggests that the mineral deformed plastically under UHP metamorphic conditions by dislocation creep through hydrolitic weakening.Omphacite grains from UHP eclogite of the Dabie Mountains in eastern China are elongated and show strong lattice preferred orientations (LPOs). Observations by the transmission electron microscopy (TEM) identified not only structures of plastic deformation occurring as free dislocation, dislocation loops and dislocation walls, but also bubbles of water present in the deformed omphacite. The bubbles attach to the dislocation loops which are often connected to one another via a common bubble. Using infrared spectroscopy (IR), two types of hydrous components are identified as hydroxyl and free-water in the omphacite. An analysis of deformation mechanism of microstructure in omphacite suggests that the mineral deformed plastically under UHP metamorphic conditions by dislocation creep through hydrolitic weakening.

关 键 词：DEFORMATION hydrolitic weakening OMPHACITE UHP eclogite Dabie Mountains China 

分 类 号：P588.3[天文地球—岩石学] P578.954[天文地球—地质学]