摘要
西藏措勤地区布嘎寺组火山岩是一套钾质到超钾质的岩石,根据化学组成可以分为中酸性和中基性火山岩。在前人研究的基础上对布嘎寺组中基性火山岩进行野外地质调查及全岩地球化学分析,并对该构造背景、源区性质及岩石成因做了进一步的研究和探讨。该火山岩具有轻稀土元素强烈富集、大离子亲石元素和高场强元素不同程度富集、弱负铕异常等地球化学特征,形成于青藏高原碰撞后的陆内拉张环境,可能是富集的上地幔和地壳不同深度不同层次的岩石不同程度部分熔融的产物。其形成与分布受青藏高原晚新生代拆离、伸展活动产生的南北向地堑控制。
The Cuoqin volcanic rocks of Miocene Bugasi Formation in Tibet are a set of potassic to ultrapotassic rocks.They are divided into two subgroups based on the chemical composition,that is,intermediate-acid group and intermediate-basic group.Based on previous studies,this paper further researches the tectonic setting,the nature of the source area and diagenesis by conducting the field geological investigation and doing geochemical analysis of the volcanic rocks from Bugasi Formation.The volcanic rocks are strongly enriched with LREE,large ion lithophile elements,high field strength elements to varying degrees,and weak negative Eu anomaly.They formed in an intra-continental extensional environment after the collision of Qinghai-Tibet Plateau and are probably the products formed by partial melting of the rocks from upper mantle and crust of different depths with different degrees.The formation and distribution is also controlled by the north-south graben which generated by the tectonic detachment and extension of Late Cenozoic on Qinghai-Tibet Plateau.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第2期204-210,共7页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
矿物学
岩石学
矿床学国家重点(培育)学科建设基金资助项目(SZD0407)
中国地质调查局区域地质调查项目
关键词
西藏错勤
布嘎寺组
中基性火山岩
源区性质
成因
Cuoqin
Tibet
Bugasi Formation
intermediate-basic volcanic rock
source region
cause
