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

作　　者：赵明福 李成福 保善东[3,4] 董基恩 祁昌炜 史连昌 魏有宁 李玉龙 ZHAO Mingfu;LI Chengfu;BAO Shandong;DONG Jien;QI Changwei;SHI Lianchang;WEI Youning;LI Yulong(Qinghai Geological Survey,Xining 810000,China;Technology Innovation Center for Exploration and Exploitation of Strategic Mineral Resource in Plateau Desert Region,Ministry of Natural Resources,Xining 810000,China;Qinghai Geological Survey Institute,Xining 810012,China;Key Laboratory of the Northern Qinghai-Tibet Plateau Geological Processes and Mineral Resource,Xining 810012,China)

机构地区：[1]青海省地质调查局,青海西宁810000 [2]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 [3]青海省地质调查院,青海西宁810012 [4]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

出　　处：《西安科技大学学报》2024年第4期748-758,共11页Journal of Xi’an University of Science and Technology

基　　金：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)。

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。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 analyzed,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 deficiency 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 environment.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 

分 类 号：P581[天文地球—岩石学]