东昆仑大灶火沟北地区花岗岩地球化学特征与构造意义
Geochemical characteristics and tectonic significance of granites in the northern area of Dazaohuogou in East Kunlun
赵明福 1李成福 1保善东 2董基恩 1祁昌炜 1史连昌 1魏有宁 1李玉龙1
作者信息
- 1. 青海省地质调查局,青海 西宁 810000;自然资源部高原荒漠区战略性矿产勘查开发技术创新中心,青海 西宁 810000
- 2. 青海省地质调查院,青海 西宁 810012;青藏高原北部地质过程与矿产资源重点实验室,青海 西宁 810012
- 折叠
摘要
东昆仑造山带矿产资源丰富、岩浆作用复杂,为分析东昆仑大灶火沟北地区加里东期花岗岩形成背景与成矿作用之间的关系,以花岗闪长岩、二长花岗岩、正长花岗岩及似斑状花岗闪长岩为研究对象,分析地球化学特征,利用岩相学、年代学方法开展研究.结果表明:大灶火沟北地区花岗岩具有过铝质和高钾钙碱性系列岩石的特点,轻稀土强烈富集、重稀土相对亏损,呈明显的负铕异常,Ba、Ta、Nb、Ce、P、Ti元素呈负异常,K、Rb、Th、Nd、Zr等元素呈正异常,与壳源花岗岩(S型)特点相似;LA-ICP-MS 锆石U-Pb 测年显示岩体形成于 439±1 Ma,时代为早志留世,形成于同碰撞构造环境;早志留世岩浆活动为区域矿产的形成提供了物质来源,形成了与志留纪碰撞型花岗岩有关的二道沟钨矿、万宝沟-昆仑河钨矿.研究成果为东昆仑造山带的构造演化提供了重要的年代学约束,也为成矿条件分析和今后的找矿部署研究提供了依据.
Abstract
The East Kunlun orogenic belt is rich in mineral resources and has complex magmatism.In order to analyze the relationship between the formation background and mineralization of Caledonian granites in the northern areas of Dazaohuogou in East Kunlun,the granites,monzogranite,syenite and porphyritic grandiorites were taken as the research objects.The geochemical characteristics were ana-lyzed,and the petrographic and chronological methods were used to conduct research.The results show that the granites in the northern areas of Dazaohuogou area have the characteristics of peraluminous and high-potassium calc-alkaline series rocks,with strong enrichment of light rare earth and relative defi-ciency of heavy rare earth,showing obvious negative europium anomalies,negative anomalies of Ba,Ta,Nb,Ce,P and Ti elements,and positive anomalies of K,Rb,Th,Nd and Zr elements,which are similar to the characteristics of crust-derived granites(S-type).LA-ICP-MS zircon U-Pb dating shows that the rock mass was formed in 439±1 Ma,Early Silurian,and formed in a syncollisional tectonic environ-ment.The Early Silurian magmatic activity provided the material source for the formation of regional minerals,and formed Erdaogou tungsten deposit and Wanbaogou-Kunlunhe tungsten deposit,which were related to the Silurian collisional-type granites.This provides an important chronological constraint for the tectonic evolution of the East Kunlun orogenic belt,and also provides a basis for the analysis of metallogenic conditions and the study of future prospecting and deployment.
关键词
地球化学/锆石U-Pb年龄/构造环境/成矿作用/大灶火沟北Key words
geochemistry/zircon U-Pb age/structural environment/mineralization/the north Dazao-huogou area引用本文复制引用
基金项目
中国地质调查局青藏专项基金项目(1212011121187)
青海省地质勘查基金项目(青国土资[2016]315号)
出版年
2024
国家科技期刊平台
NSTL
万方数据