摘要
对湘东北三墩铜铅锌矿区花岗岩进行了系统的锆石U-Pb年代学、岩石地球化学和Hf同位素分析。LA-ICP-MS锆石U-Pb定年表明,三墩铜铅锌矿区花岗岩成岩年龄为131.9±1.1Ma。三墩铜铅锌矿区花岗岩为一套强过铝质钙碱性系列花岗岩,富集U、Ta、Pb,亏损Ba、Nb、Sr、Zr、Ti等元素,稀土元素配分模式为右倾配分模式,具有弱负Eu异常。Hf同位素分析表明,三墩铜铅锌矿区花岗岩燕山晚期锆石ε_(Hf)(t)值为-5.9^-2.4,Hf同位素二阶段模式年龄为1558~1338Ma,表明其物质来源于中元古代古老地壳岩石部分熔融。749.5Ma继承锆石核的ε_(Hf)(t)值为+4.8,Hf同位素二阶段模式年龄为1355Ma,暗示其物质来源有幔源物质加入。三墩铜铅锌矿区花岗岩可能是由于中下地壳的熔融岩浆形成后,混入少量幔源物质上侵形成的。
In this paper,the authors studied the petrogenesis and tectonic-significance of the granite from the Sandun Cu-Pb-Zn polymetallic deposit in northeastern Hu'nan Province by means of zircon U-Pb isotope chronology,whole rock geochemistry and Hf isotope.LA-ICP-MS zircon U-Pb dating yielded crystallization age of131.9±1.1Ma for the Sandun granite.The Sandun granite is a peraluminous high-Al calc-alkaline intrusive granite.The rocks are characterized by high U,Ta,Pb and low Ba,Nb,Sr,Zr,Ti values.The REE distribution patterns are strongly LREE enriched and HREE depleted,with weakly negative Eu anomalies.The Hf isotope analyses show that theεHf(t)values of the late Yanshanian granite zircons are between-5.9and-2.4,and the two stage Hf model ages ranging from1558Ma to1338Ma,which indicates that its parental magma was derived from partial melting of rocks of Middle Proterozoic paleo-crust.Inherited zircon with an age of749.5Ma has theεHf(t)of+4.8and two stage Hf model age of1355Ma,respectively,which indicates that its parental magma was mainly derived from the mantle.The Sandun granite probably resulted from the formation of the molten magma in the middle and lower crust and the formation of a small amount of mantle derived material.
作者
张鲲
徐德明
胡俊良
卢友月
黄皓
ZHANG Kun;XU Deming;HU Junliang;LU Youyue;HUANG Hao(Wuhan Institute of Geology and Mineral Resources, Wuhan 430205, Hubei, China)
出处
《地质通报》
CAS
CSCD
北大核心
2017年第9期1591-1600,共10页
Geological Bulletin of China
基金
中国地质调查局项目<钦杭成矿带(西段)重要金属矿床成矿规律及找矿方向研究>(编号:1212011085405)
<钦杭成矿带西段资源远景调查评价>(编号:12120113067200)和<湘南柿竹园-香花岭有色稀有金属矿产集中开采区地质环境调查>(编号:DD20160334)
