冀北张宣高变质花岗岩-绿岩带花岗岩类岩石学、地球化学及锆石铀-铅地质年代学  

PETROLOGY, GEOCHEMISTRY AND ZIRCON U-PB GEOCHRONOLOGY OF GRANITOIDS WITHIN HIGH-GRADE METAMORPHIC GRANITE-GREEN-STONE BELT IN ZHANGXUAN AREA NORTHERN HEBEI PROVINCE

作　　者：陈志宏[1] 胡小蝶[1] 赵彦明[1] 王魁元[1] 

机构地区：[1]地矿部天津地质矿产研究所,天津300170

出　　处：《前寒武纪研究进展》1997年第3期29-39,共11页Progress in Precambrian Research

摘　　要：张宣高变质花岗岩－绿岩带内早期花岗质侵入体是以英云间长岩和花岗间长岩为主体的ＴＴＧ岩系，经历了麻粒岩相高级变质作用的改造，已变质成以含紫苏辉石为特征的片麻岩类岩石。麻粒岩相峰期变质作用的时代为２３９０±１９Ｍａ。紫苏花岗岩属典型岩浆成因侵入岩，其侵位成岩时代为２３９０±２４Ｍａ，是区域麻粒岩相峰期变质作用期间长英质熔浆直接结晶的产物。钾质花岗岩类具多种不同的岩石类型，为一系列小规模的富钾质花岗岩侵入体，是与紫苏花岗岩同一构造岩浆活动事件的产物。麻粒岩相峰期变质作用、岩浆活动时代的一致性，表明了本区太古宙末－古元古代早期，由于大规模构造运动，麻粒岩相变质作用由峰期变质条件向相对低温低压条件演化、花岗岩－绿岩带基底岩石由地壳深部向地壳浅部抬升、并同时伴随紫苏花岗岩及钾质花岗岩等大规模岩浆侵入活动的区域地壳演化规律。The early granitic intrusions within zhangxuan high-grade metamorphic granitegreenstone belt were TTG's consisting maily of tonalite and granodiorite which had been subjectedto the rework of granulite-factes metamorphism and retrogressive metamorphisrn later, and hadbeen reworked into gneisses containing hypersthene. The peak granulite-factes metarnorphismoccurred at 2390 ±19Ma. The Charnockite in this region was originated from igneous rock ofmagmatic activity and formed in 2390 ± 24Ma, It crystalized direct from quartzofeldspathicmagma during peak granulite-factes metamorphism. Also a series of smalLscaled potassic graniteswith different mineral assemblage occurred and formed in the same tectono-magmatic event withcharnockite. The contemporous relationship between peak granulite-factes metamorphism andmagmatic activity demonstrated the following crustal evolutionary features: the largescaledtectonic activity occurred in the early stage of Paleoproteyozoic era (2390Ma ± ), the granulitefacies metamorphism altered in the range from peak metamorphic conditions to relative lowertemprature and pressure environment, and uplift of basement rock within Zhangxuan granitegreenstone belt from lower crust took place, coeval with the intruded activity of charnockite andPotassic granites.

关 键 词：花岗岩 岩石学 地球化学 锆石 铀-铅 地质年代 

分 类 号：P588.121[天文地球—岩石学] P597[天文地球—地质学]