东天山中段不同构造环境火山岩地球化学特征  

Geochemical Characteristics of Volcan rocks within Different Tectonic settings in the Centrl Part of East Tianshan Mountains

作　　者：姬金生[1] 陶洪祥[1] 杨兴科[1] 

机构地区：[1]西安地质学院

出　　处：《岩石矿物学杂志》1994年第4期297-304,共8页Acta Petrologica et Mineralogica

基　　金：国家三○五项目

摘　　要：东天山中段分布有阿齐山岛弧区（Ⅱ＿２）安山岩类和海沟区（Ⅱ＿１）混杂岩带玄武岩类火山岩，不同构造环境形成的火山岩各自具有与其环境相对应的地球化学特征。在常量元素、微量元素及稀土元素特征方面，它们可与世界上典型构造环境区形成的火山岩相对比。从地球化学特征发现，Ⅱ＿２区火山岩主要与早石炭世吐鲁番洋壳向塔里木陆壳俯冲有关，形成了Ⅱ＿２区钙碱性安山质火山岩。Ⅱ＿１区混杂岩带内呈洋壳残片产出的玄武岩类与吐鲁番洋盆的扩张有成因联系，岩石属于大洋拉斑玄武岩类。Two kinds of volcanic rocks have been recognized in the central part of east Tianshan Mountains. One is andesitic volcanic rock along the Aqishan island arc(Ⅱ_2),and the other is basaltic volcanic rock in the melange zone of the Qiugeminshi trench(Ⅱ_1).Volcanic rock formed in each tectonic setting has its unique geochomical features that can be matched with the setting.Volcanic rocks in this region are comparable with the volcanic rocks formed in the rogion of typical tectonic settings in such aspects as major elements,trace elements and REE. Based on the differont geochomical features,the authors consider that volcanic rocks in the Aqisshan island arc(Ⅱ_2)were mainly in conjunction with the subduction of Tulufan oceanic crust into Tarim contincntal crust in early Carboniferous, being mainly calc-alkaline volcallic rocks. Basaltic volcanic rock,which occurred as a piece of oceanic crust in the melange zone of the trench(Ⅱ_2),was mainly associated with the exten-sion of Tulufan oceanic basin,belongiug to oceanic tholeiite.

关 键 词：火山岩 构造环境 地球化学 

分 类 号：P588.14[天文地球—岩石学]