西藏冈底斯中段晚侏罗—早白垩世花岗岩特征  

Geological characteristics and tectonic significance for late Jurassic-early Cretaceous granite in middle Gangdis,Tibet

作　　者：黄俊平[1] 曹圣华[1] 陈振华[1] 廖六根[1] 

机构地区：[1]江西省地质调查研究院,江西南昌330201

出　　处：《资源调查与环境》2006年第4期277-285,共9页Resources Survey & Environment

基　　金：国家地调局1:25万措麦幅区域地质调查项目资助

摘　　要：对西藏冈底斯中段1∶25万措麦区幅区域地质调查中新发现的侵入于晚古生代地层中被古近纪林子宗群火山岩喷发沉积不整合覆盖的尼雄超单元、许如错超单元进行了解体,划分了7个单元。许如错超单元同位素年龄值154.2 Ma±3.8 Ma(锆石U-Pb)、141 Ma(锆K-Ar),时代为晚侏罗世,尼雄岩体中获锆K-Ar法年龄值114 Ma、106 Ma,时代为早白垩世,其地球化学及同位素特征反应两岩体为过铝型高钾钙碱性壳幔混合型花岗岩,形成于活动陆缘火山弧构造环境,为大陆弧花岗岩,与雅江洋向北和班-怒洋向南俯冲有关。On the basis of the regional investigation of the 1： 250,000 Cuomei District Sheet and the description of the Xurucuo pluton in geology, petrology, geochemistry of rock and isotopic chronology early Cretaceous Nixiong pluton and late Jurassic Xurueuo bodies are analyzed from the aspect of tectonic enviomment. The result showed the granites of Late Jurassic Early Cretaceous were formed in the tectonic environment of volcano are in an active continental margin and their formation had close relation with the Yaluzangbujiang Ocean Plate subducting northward,which had important tectonic significances for researching the properties of the Gangdis Magmatite Zone and the evolution of the Yaluzangbujiang Tethys Ocean.

关 键 词：尼雄超单元 许如错超单元 大陆弧花岗岩 冈底斯 西藏 

分 类 号：P588.1[天文地球—岩石学]