内蒙古某金矿区韧性剪切带及其与金矿化的关系  

The Feature of Ductile Shear Zone and Relationshipof the a Certain Gold Deposits in Inner Mongolia

作　　者：张臣[1] 朱亮璞[1] 

机构地区：[1]北京大学地质学系

出　　处：《河北地质学院学报》1994年第4期345-353,共9页

基　　金：国家自然科学基金

摘　　要：内蒙古某金矿区发育ＮＷＷ向韧性剪切带，糜棱岩分带明显，由糜棱岩化岩石、糜棱岩和糜棱片岩组成．根据韧性剪切带内Ｓ∧Ｃ夹角、拉伸线理及Ｓ型组构指示韧性剪切带在平面上具右行剪切特征．剪切应变值４．５～５．７，应变性质以简单剪切为主的平面应变兼有压扁变形特征．野外观察，岩石薄片鉴定及岩石化学分析表明，岩石明显发生退化变质现象，剪切带边部到中心，矿物和化学成分都发生了明显变化，ＳｉＯ２、Ｆｅ２Ｏ３、Ｎａ２Ｏ在剪切带中心明显降低，ＭｇＯ、ＣａＯ、Ｋ２Ｏ在剪切带中随变质变形强度增加而增加．金矿床沿韧性剪切带分布，含金石英脉和含金蚀变岩金矿体明显受剪切带控制．金矿化与韧性剪切作用、韧性剪切退变质作用及后期脆性构造叠加和中酸性岩浆活动有关，说明本区金矿的形成是多阶段成矿作用的结果．The ductile shear zone trending NWW were developed in a certain gold depositisarea. The ductile shear metamorphic rock can be divided into three groups:mylonitiaization rock, mylonite, mylonite schist. According to S∧C included angle,linealion and S type fabrics within ductile shear zone indicates that shear zone is the featureof right lateral shear in plane, Shear strain r=4.5-5.7, Strain nature is characterized byplane strain of simple shear with flaser deformation. The field observation, thin section examination and major clement analysis all indicate both the minerals and the chemical composition have altered from sides to the center of the shear zone: SiO2, Fe2O3, FeO, Na2Owere decrease,MgO, CaO. K2O were increase with increase of deformation intensity. Theductile shear zone controlled the distribution of auriferous quartz and altered rooks golddeposits. The gold mineralization is related to ductile shearing, degradation metamorphism,Structure reduplication of late period and meso-acid amgmatism. The formation of golddeposits is the result of multistage mineralization.

关 键 词：剪切带 金矿床 糜棱岩 矿化 

分 类 号：P618.510.5[天文地球—矿床学]