北淮阳构造带鲜花岭找矿远景区铜铅锌矿化相关侵入岩的锆石U-Pb年龄和Hf同位素特征  

U-Pb AGE AND HF ISOTOPIC CHARACTERISTICS OF ZIRCONS FROM INTRUSIVES CONCERNED WITH COPPER, LEAD,ZINC MINERALIZATION IN THE XIANHUALING PROSPECT OF THE NORTHERN HUAIYANG TECTONIC BELT

作　　者：王波华[1] 倪培[2] 王国光[2] 方明[1] 李利[2] 张怀东[1] WANG Bo-hua;NI Pei;WANG Guo-guang;Fang Ming;LI Li;ZHANG Huai-dong(No. 313 Unit of Bureau of Geology and Mineral Exploration of Anhui Province, Lu'an Anhui 237010, China;National KeyLaboratory for the Study of Metallogenic Mechanism of Endogenous Metallic Ore Deposit, Institute of Geological Fluid, School of Geosciences and Engineering, Nanjing University, Nanjing, Jiangsu 210046, China)

机构地区：[1]安徽省地质矿产勘查局313地质队,安徽六安237010 [2]南京大学内生金属矿床成矿机制研究国家重点实验室,地质流体研究所,地球科学与工程学院,江苏南京210046

出　　处：《安徽地质》2018年第3期176-181,共6页Geology of Anhui

基　　金：国家重点研发计划项目(2016YFC0600206);安徽省霍山县凌家冲地区金矿成矿地质条件和成矿规律研究项目;中央高校基本科研业务费专项资金(020614380065)资助

摘　　要：安徽北淮阳构造带鲜花岭找矿远景区发育中酸性侵入岩相关的铜铅锌矿化,本次研究选取铜铅锌矿化相关的鲍冲二长岩开展锆石LA-ICP-MS U-Pb年代学及LA-MC-ICP-MS锆石Lu-Hf同位素分析。结果显示锆石Th/U比值为0.54-1.33,属于典型岩浆成因锆石。鲍冲二长岩锆石U-Pb年龄加权平均值为(124±2)Ma(n=10,MSWD=3.2);结合锆石自形、发育岩浆环带等特点,该年龄是鲍冲二长岩的结晶年龄。这一形成年龄对应于大别造山带构造垮塌事件,因此,北淮阳构造带鲜花岭地区铜铅锌矿化可能形成于早白垩世后岩石圈减薄环境。原位锆石Lu-Hf同位素研究显示,鲍冲二长岩的εHf(t)在-15.7～-10.2之间,两阶段锆石Hf模式年龄为1.82～2.17 Ga,指示岩浆源区为古元古代的基底。结合前人资料,安徽北淮阳构造带成矿作用可以划分为三期:第一期晓天盆地的火山热液型金矿化(130 Ma),第二期鲍冲岩体有关的铜铅锌矿化(124 Ma)和第三期的斑岩型钼矿化(114Ma)。Mineralization of copper,lead and zinc related to the intermediate acidic intrusions is developed in the Xianhualing prospect of Northern Huaiyang tectonic belt of Anhui Province.In this paper,zircon LA-ICP-MS U-Pb chronological study and LA-MC-ICP-MS zircon Lu-Hf isotopic analysis were carried out on the Baochong monzonite granite related to the mineralization of copper,lead and zinc.The results show that the zircon Th/U ratio is0.54-1.33,indicating a typical magmatic origin for the zircon.The weighted average of U-Pb age of zircon from the Baochong monzonite is124±2Ma(n=10,MSWD=3.2),and is thought to be the crystallization age o f the monzonite with the id iomorphic zir con and development of magma tic zoning being taken into consideration.This age corresponds to the tectonic collapse in the Dabie orogenic belt.Therefore,the copper,lead,zinc mineralization in the Northern Huaiyang tectonic belt may be formed in the lithospheric thinning environment later than ear ly Cretaceous.Lu-Hf isotopic s tudies of in-situ zircons show that the Baochong monzonite hasεHf(t)between-15.7^-10.2,and two-stage zircon Hf model age of1.82~2.17Ga,indicating that the magmatic origin is the basement of Paleoproterozoic.By reference to previous data,mineralization in the Northern Huaiyang tectonic belt of Anhui Province can be divided into:stage one,volcanic hydrothermal gold mineralization(130Ma)in the Xiaotian Basin;stage two,copper,lead,zinc mineralization(124Ma)related to the Baochong rock mass;and stage three,porphyry molybdenum mineralization(114Ma).

关 键 词：铜铅锌矿化 鲍冲二长岩 LA-ICP-MS锆石U-PB定年 锆石HF同位素 早白垩世 造山带构造垮塌 

分 类 号：P612[天文地球—矿床学] P618.2[天文地球—地质学]