湘东邓阜仙二云母花岗岩锆石U-Pb年代学及地球化学研究  

Zircon U-Pb Geochronology and Geochemistry Characteristics of Dengfuxian Two-mica Granite, Eastern Hunan Province, China

作　　者：黄卉[1,2] 马东升[1] 陆建军[1] 蔡杨[1] 谢旭[3] 

机构地区：[1]内生金属矿床成矿机制研究国家重点实验室南京大学地球科学与工程学院,江苏南京210093 [2]广东省地质过程与矿产资源探查重点实验室中山大学地球科学系,广东广州510275 [3]江苏省地质调查研究院,江苏南京210018

出　　处：《矿物学报》2013年第2期245-255,共11页Acta Mineralogica Sinica

基　　金：国家重点基础研究发展计划项目(编号:2012CB416702);中国地质调查局调查项目(编号:1212011085407).

摘　　要：邓阜仙花岗岩体位于湖南茶陵县东北部,是一个由黑云母花岗岩、二云母花岗岩和白云母花岗岩组成的复式岩体。其中,二云母花岗岩与钨成矿关系最为密切。锆石LA-ICP-MS U-Pb同位素定年测得二云母花岗岩的加权平均年龄为154.4±2.2 Ma(MSWD=5.6,n=20),为燕山早期侵位。岩石地球化学研究表明,邓阜仙二云母花岗岩具有高硅、富碱、贫镁铁、强过铝质和高分异的特点。花岗岩相对富集大离子亲石元素Cs、Rb、K和高场强元素Th、U、Pb,亏损Ba、Sr和Ti等,稀土总量偏低(ΣREE平均值为90.59×10-6),轻稀土相对富集(LREE/HREE比值平均为9.97),铕负异常显著(δEu平均值为0.34),稀土元素配分模式呈右倾型。根据区域地质和花岗岩地球化学特征,确定岩石为S型花岗岩,形成于造山后伸展构造环境。The Dengfuxian granitic body located in the northeast Chaling,Hunan province,China,is composed of biotite granite,two-mica granite and muscovite granite.Among them,two-mica granite has closely related with tungsten mineralization.The zircon LA-ICP-MS U-Pb weighted average age of 154.4±2.2 Ma（MSWD=5.6,n=20） indicates that the intrusion of two-mica granite occurred at Early Yanshanian.Dengfuxian two-mica granite is strongly peraluminous,with high Si and alkali contents and low Mg and Fe contents,showing geochemical characteristics of high differentiation.Two-mica granite is rich in large ion lithophile elements（Cs,Rb and K） and high field strength elements（Th,U and Pb）,but deplete in Ba,Sr and Ti.These two-mica granitic rocks have low ΣREE content（average ΣREE=90.59×10-6）,pronounced negative Eu anomaly（average δEu=0.34） and LREE enrichment（average LREE/HREE=9.97）.The chondrite-normalized REE distribution pattern is right-inclining type.Combining the regional geology with bulk rock geochemistry,Dengfuxian two-mica granite is believed to be S-type granite and formed in an extensional tectonic setting during Early Yanshanian.

关 键 词：锆石U-PB年龄 地球化学特征 钨矿 花岗岩 邓阜仙 南岭 

分 类 号：P579[天文地球—矿物学] P581[天文地球—地质学]