西藏东巧地区东穷玄武岩岩石地球化学特征及地质意义  

Geochemical Characteristics of Rocks and Geological Significance of Basalt in Dongqiang Area of Tibet

作　　者：孔维华 屠江海 尹本银 邹阮兵 刘铭敏 

机构地区：[1]湖北省地质局第六地质大队,湖北孝感432100

出　　处：《资源环境与工程》2016年第6期801-808,共8页Resources Environment & Engineering

基　　金：西藏1:5万班戈江错地区H46E002003等6幅区域地质矿产调查项目(项目编号:1212011221082)

摘　　要：1∶25万班戈幅区域地质调查在东巧地区安多县强马镇南东穷一带圈定出侏罗纪机部乡蛇绿岩带。通过"西藏1∶5万班戈江错地区6幅区调"野外地质调查研究,机部乡蛇绿岩带是由玄武岩、辉长岩、灰岩、放射虫硅质岩等岩石形成的一套洋岛海山组合,其化学特征显示具有富钛、碱、铝,低硅、镁,明显富集大离子亲石元素Rb、Ba、Th,亏损Sr、Y、Yb,在TiO_2-Mn-P_2O_5构造环境判别图中,显示洋岛碱性玄武岩;与蛇绿岩相伴生的沉积物中化石分析鉴定,确定蛇绿岩形成时代为晚三叠世,证实了班公湖—怒江结合带中段在晚三叠世已经打开。Through the six regional geological surveys of 1 ： 50 thousand in Bangejiangcuo area of Tibet, Ophiolite belt inJibu township is a combination of a set of ocean island formed by basalt, gabbro,limestone and radiolarian bedded chert.The chemical characteristics shows rich titanium, alkali, aluminum, low silicon, low magnesium, significantly enriched inion lithophile element Rb, Ba, Th, loss of Sr,Y,Yb. In the discriminant TiO2-Mn-P205 tectonic map, show ocean islandis alkaline basalt; identification of fossil sediments associated with ophiolite. Analysis and identification of fossil sedi-ments associated with ophiolite, it determines the ophiolite formed inzone has been opened in the Late Triassic.

关 键 词：班公湖—怒江结合带 洋岛海山 放射虫硅质岩 

分 类 号：P588.14[天文地球—岩石学]