北疆祖鲁洪花岗岩体的主要特征及成因  

BASIC CHARACTERISTICS AND GENESIS OF ZULUHONG GRANITIC BODY IN NORTH XINJIANG

作　　者：周有勤[1] 王奎仁[1] 

机构地区：[1]中国科学技术大学地球和空间科学系,合肥230026

出　　处：《岩石学报》1993年第1期70-76,共7页Acta Petrologica Sinica

基　　金：国家305项目Ⅳ_2课题

摘　　要：祖鲁洪黑云母花岗岩系海西中期岩浆活动的产物,全岩Rb-Sr等时线年龄为284Ma。岩石中钛铁矿含量明显大于磁铁矿;岩石化学特征为高硅、富碱,岩体的^(87)Sr/^(86)Sr初始比值为0.7064,稀土分布模式与壳型花岗岩相同,δEu值为0.37。全岩δ^(18)O值为11.18‰,石英的δ^(18)O值为12.84‰。岩体主要由地壳岩石经部分熔融所形成,具有S型和陆壳改造型花岗岩的特征。The whole-rock Rb-Sr isochronous age of Zuluhong biotite granite in North Xinjiang is 284.14Ma, and the K-Ar age of biotite is 300.8Ma. So the granitic body is a product of Middle Hercynian magmatism. Content of ilmenite (28g/t) in the granite is obviously higher than that of magnetite (11g/t). Petrochemically the granite is characterized by high silica (SiO_2=73.36%) and alkalies (K_2O+Na_2O=7.76%). Biotite is rich in Al_2O_3(15.81%) and poor in MgO(5.67%), and belongs to Fe-biotite. The whole-rock δ^(18)O value in the granitic body is 11.18‰, δ^(18)O value of quartz is 12.84‰ and biotite 7.09‰. The chondrite-normalized REE pattern of the granitic body is same as that of crust-derived granite, δEu=0.37. All these data indicate that the rock-forming materials of granitic body had derived from the crust. The initial ^(87)Sr/^(85)Sr ratio(0.7064), Rb/Sr ratio(0.37～2.24) and ΣREE(159.2ppm) in the granitic body are low. It indicates an adding of mantle materials to the granitic body.

关 键 词：花岗岩 岩石 成因 新疆 岩体 

分 类 号：P588.121[天文地球—岩石学]