摘要
郎村钨钼矿床位于浙西北安吉县境内,是钦杭成矿带东段新发现的中型斑岩型矿床.矿体主要产于花岗斑岩岩体中以及岩体与围岩的内外接触带中.为探讨成矿岩浆来源及动力学背景,在野外地质工作基础上对矿区与成矿相关的花岗斑岩进行了详细的岩相学、锆石年代学和岩石地球化学研究.结果表明,花岗斑岩LA-ICP-MS锆石U-Pb年龄为129.7±1.1 Ma.岩石地球化学结果显示高硅、富碱和弱过铝质特征,属于钾玄岩系列花岗岩类,其稀土配分曲线显示轻稀土富集型特征,并具有明显的Eu负异常(δEu=0.36~0.40).高硅、富碱、高的10000 Ga/Al比值(2.57~2.90)和高Zr+Nb+Ce+Y值(379.5×10^(-6)~462.0×10^(-6)),显示了A型花岗岩的特征.花岗斑岩全岩的(87Sr/86Sr)i为0.70717~0.70908,ε_(Nd)(t)为-6.1~-4.0,二阶段模式年龄(T_(DM2))为1.25~1.42 Ga;锆石的ε_(Hf)(t)为-5.94~-0.87,二阶段模式年龄(TMD2)介于1.23~1.56 Ga,表明花岗斑岩来源于中元古代地壳部分熔融,并有少量地幔物质的参与.花岗斑岩可能形成于中国东部岩石圈伸展—减薄的构造背景下,是华南大规模岩浆-构造事件的产物.
The Langcun tungsten-molybdenum deposit is a medium porphyry-skarn type deposit in the Northwest Zhejiang Province,western Qinzhou-Hangzhou metallogenic belt(QHMB).In this paper,it analyzed the petrological,chronological and geochemical characteristics of the ore-forming related granite porphyry in this deposit to constrain its genesis and interpret its tectonic significance.Granite porphyry formed at 129.7±1.1 Ma(zircon U-Pb,LA-ICP-MS)and belongs to shoshonite series with high SiO_(2),alkali contents,and weakly peraluminous.The characteristics,i.e.,right-dipping chondrite normalized REE pattern with negative Eu anomalies(δEu=0.36-0.40)and the 10000 Ga/Al and Zr+Nb+Ce+Y values range from 2.57 to 2.90 and 379.5×10^(-6) to 462.0×10^(-6),respectively,suggest that the granite porphyry belongs to A-type granite.Whole rock Sr-Nd compositions are characterized by ISr andε_(Nd)(t)range from 0.70717 to 0.70908 and-6.1 to-4.0,respectively,with Nd model ages of 1.25 to 1.42 Ga.Meanwhile,zircon Hf compositions are characterized byε_(Hf)(t)=-5.94 to-0.87 with two stage model ages of 1.23 to 1.56 Ga.All these evidences suggest that granite porphyry is formed by an ancient continental crust mixed with mantle material source under the tectonic of lithosphere extension and thinning in South China.
作者
崔凯
谢玉玲
曲云伟
唐燕文
李腊梅
陈琦
Cui Kai;Xie Yuling;Qu Yunwei;Tang Yanwen;Li Lamei;Chen Qi(Civil and Resource Engineering School,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;Institute of Mineral Resources Research,China Metallurgical Geology Bureau,Beijing 101300,China;No.1 Geological Exploration Unit of Zhejiang Province,Hangzhou 310012,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2023年第10期3725-3742,共18页
Earth Science
基金
国家“十二五”科技计划项目(No.2011BAB04B00)
国土资源部公益性行业基金项目(No.201011011).
关键词
郎村钨钼矿床
花岗斑岩
地球化学
年代学
岩石学
矿床学
Langcun W-Mo deposit
granite porphyry
geochemistry
geochronology
petrology
mineralogy
