甘肃白银地区中基性火山岩岩石地球化学特征及构造背景  

The geochemical characteristic for medio-basic volcanic rock from Baiyin area,Gansu Province

作　　者：李莹 付国民[2] 苗箐[3] 李磊[3] 

机构地区：[1]陕西地矿局,陕西宝鸡721300 [2]长安大学资源学院,陕西西安710054 [3]中国石化中原油田分公司,河南濮阳457001

出　　处：《兰州大学学报（自然科学版）》2009年第F06期55-60,共6页Journal of Lanzhou University(Natural Sciences)

基　　金：国土资源部兰州幅1:25万区域地质调查基金项目(J48C004002)

摘　　要：白银地区火山岩位于北祁连造山带东缘,通过对该地区震旦纪中基性火山岩的岩石地球化学研究,探讨北祁连造山带东缘火山岩的构造背景和地幔属性.研究表明:中基性火山岩岩石类型主要为粗面玄武岩和玄武质粗面安山岩,火山岩表现出高碱、低Ti、富集LREE、LILE、具有明显的Nb的负异常、低ε_(Nd)的地球化学特征.岩浆源区为富集的岩石圈地幔,形成于大洋岛弧的构造环境.Baiyin area, located in eastern margin of Northern Qilian orogenic belt, through studying the geochemical analysis of Sinian period medio-basic volcanic rock, the tectonic settings and mantle property of volcanic rocks in eastern margin of Northern Qilian orogenic belt are discussed. They mainly consist of trachyphonolite and basaltic trachyandesite. The study indicated the geochemical characteristics of mediobasic volcanic rocks, and they are showed high alkali, low Ti, enriched in LREE and LILE, negative Nb anomalies obviously, low 6Nd. The Magma Source is the lithosphere mantle, it is likely from the environment from fis-land-arcvolcanic.

关 键 词：中基性火山岩 地球化学 成因 白银 

分 类 号：P588.14[天文地球—岩石学] P588.145[天文地球—地质学]