辽宁阜新排山楼金矿区岩浆岩锆石SHRIMP定年及其意义  

SHRIMP U-Pb zircon age of magmatic rock in Paishanlou gold mine district, Fuxin, Liaoning Province, China

作　　者：罗镇宽[1] 苗来成[1,2] 关康[1] 裘有守[1] Y.M.Qiu N.J.McNaughton D.I.Groves 

机构地区：[1]天津地质研究院 [2]中国科学院地质与地球物理研究所,北京100029 [3]Centre for Strategic Mineral Deposits,Department of Geology amd Geophysics,the University of Western Australia

出　　处：《地球化学》2001年第5期483-490,共8页Geochimica

基　　金：中国和澳大利亚经济技术合作研究基金;国家攀登预选项目(95-预-25)

摘　　要：采用先进的SHRIMP定年技术对辽宁阜新排山楼金矿区成矿前变形的闪长玢岩脉、变形花岗斑岩脉、成矿后的闪长玢岩脉和大石头沟黑云母花岗岩的锆石进行了U-Pb年龄测定,获成矿前变形闪长玢岩脉的206Pb/238Pb年龄为(126±2)Ma;变形花岗斑岩脉为(124±1)Ma;成矿后的闪长玢岩脉为(125±1)Ma;大石头沟黑云母花岗岩为(124±1)Ma。这4类岩浆岩的年龄在误差允许范围内可基本视为同时代的。这一结果揭示,排山楼韧性剪切带型金矿床是中生代燕山晚期形成的,这与前人采用Ar-Ar法测得矿石蚀变黑云母的年龄犤(124.4±0.391)Ma犦是一致的。这表明,在中国东部,许多产在前寒武系岩层中、受韧性剪切带控制的金矿床形成时代是中生代燕山晚期。广泛产在胶东、辽西北票—蒙东赤峰、河北张家口和内蒙古乌拉山等地区的金矿床都主要是中生代燕山晚期形成的,表明燕山晚期是中国东部最重要的金矿化期。Paishanlou gold deposit is situated in Fuxin area at the margin of the North China craton occurring in Proterozoic meta volcanic clastic rock of Waziyu Formation. Ore bodies in layeroid and lenticular forms are strictly controlled by ductile shear zone and hosted in biotite anorthose gneissic mylonite and felsic mylonite, generally in altered mylonite. Pyrite, minor poly metal sulfides and native gold are the main ore minerals accounting for about 1%～3%of the ore. Sericite, biotite, feldspar are main gangue minerals. YanshanianDashitougou biotite granite batholith is widely outcropped in the north of the mine district and various dykes are developed in the mine district. The dykes are the deformed pre ore diorite porphyrite and granite porphyry, the post orerhyolite porphyry, diabase and lamprophyre. SHRIMP technique is applied to determine U Pb age of the deformed pre ore diorite porphyrite and granite porphyry dykes and the post ore diorite porphyrite dykes and the Dashitougou granitebatholith. Measurement on the zircon from the deformed pre ore diorite porphyrite shows 206Pb/ 238Pb age of (126±2) Ma and (124±1) Ma from the deformed pre ore granite porphyry; (125±1) Ma and (124±1) Ma from the post ore diorite porphyrite and Dashitougou batholith respectively. Therefore, the four kinds of magmatic rocks may be formed contemporaneously in the permitted measurementlimit of error. The Ar Ar age measured on biotite from the ore before is (124.4±0.4) Ma. The close coincidence indicates that Paishanlou gold deposit was formed in Yanshanian Period and the contemporaneous magmatic activities provided heat dynamics and thermal fluid. The gold deposit, together with the other Yanshanian gold deposits, such as those in Jiaodong (Shandong Province), Beipiao (west Liaoning Province) Chifeng (Inner Mongolia), Zhangjiakou (Hebei Province) and Wulashan (Inner Monglia) which are all located in Precambrian rocks and controlled by ductile shear zone imply that Yanshanian Period is major Au ore forming epoch in

关 键 词：SHRIMP定年 岩浆岩 金矿床 燕山期 辽宁 形成时代 韧性剪切带 中生代 

分 类 号：P618.51[天文地球—矿床学]