钦杭成矿带南段阳春盆地中侏罗世钨铅锌矿床的厘定及意义  

Discovery and significance of Middle Jurassic W-Pb-Zn deposits in the Yangchun basin,southern Qin-Hang metallogenic belt

作　　者：赵海杰[1] 郑伟 欧阳志侠 汪汝澎 杨胜虎 ZHAO HaiJie;ZHENG Wei;OUYANG ZhiXia;WANG RuPeng;YANG ShengHu(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,CAGS,Bejing 100037,China;Geology Bureau for Nonferrous Metals of Guangdong Province,Guangzhou 510080,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037 [2]广东省有色金属地质局,广州510080

出　　处：《岩石学报》2021年第3期927-942,共16页Acta Petrologica Sinica

基　　金：国家自然基金项目(41773041、41702083、41203036);国家重点研发计划项目(2017YFC0601403)联合资助。

摘　　要：钦杭成矿带是华南地区一条著名的中生代斑岩-矽卡岩铜铅锌多金属成矿带,其南段阳春盆地内以集中发育白垩纪钨锡多金属矿床为特征,侏罗纪成矿仅有个别铜铁钼矿床报道。因此,区内有关侏罗纪成矿特征、矿化元素组合、成岩成矿物质等问题尚不明晰。本文对阳春盆地内黑石岗矽卡岩型铅锌矿床和留洞石英脉型钨钼矿床进行了成岩成矿年代学研究。结果显示,黑石岗花岗闪长岩的锆石U-Pb等时线年龄为164.9±0.7Ma,留洞钨钼矿的辉钼矿Re-Os同位素等时线年龄为164.6±4.0Ma,加权平均值161.2±2.4Ma,表明区内铅锌钨钼成矿作用均发生于中侏罗世晚期。该结果不仅扩充了区内侏罗纪成矿作用规模,同时丰富了区内侏罗纪矿化元素组合,包括铜铁-铜铅锌-钨钼等多金属矿床。留洞矿床辉钼矿具有极低的Re含量(514.6×10^(-9)~2365×10^(-9)),黑石岗花岗闪长岩的ε_(Hf)(t)值变化于-5.2~-2.9之间,平均为-4.3。通过对成矿带内侏罗纪铜多金属矿床的相关数据综合及对比分析,本文认为阳春盆地此时期成岩成矿物质均以壳源为主,可能混有少量幔源物质。黑石岗和留洞矿床成岩成矿年龄的确定为下一步在阳春盆地开展侏罗纪矿床找矿勘探提供了重要信息,也为进一步深入研究钦杭成矿带侏罗纪成岩成矿作用动力学背景提供了参考。The Qin-Hang metallogenic belt is famous for amount of Mesozoic porphyry-skarn Cu-Pb-Zn polymetallic deposits in South China.The Yangchun basin is located in its southern part and is characterized by abundant Cretaceous W-Sn polymetallic ore deposits with few Jurassic Cu-Fe-Mo deposit.The Jurassic deposits in terms of metallogenic and metal associations in Yangchun basin are unclear.Here we present geochronologic data for Heishigang Pb-Zn-Cu deposit and Liudong W-Mo deposit in Yangchun basin.The Heishigang is a skarn deposit related to granodiorite and its orebody occur as laminated and lenticular in the contact between the granodiorite with the Carboniferous carbonate.Liudong ore-bearing quartz veins develop in the Cambrian metamorphic rock.Zircon UPb dating and molybdenite Re-Os geochronology indicate that the emplacement of the Heishigang granodiorite and the associated Pb-ZnCu mineralization occurred at 164.9±0.7 Ma,consistent with the Liudong W-Mo mineralization at 164.6±4.0 Ma.The results demonstrated that the Jurassic mineralization in Yangchun basin includes not only the Cu-Fe-Mo ores,but also W-Sn-Pb-Zn-Cu deposits.The rhenium contents of Liudong molybdenite samples are in the range of 514.0×10^(-9)~2370×10^(-9),and the Heishigang rocks show negative zirconεHf(t)values(-5.2~-2.9),suggesting the W-Mo and magmas mainly generated through the old crustal components and a little mantle material inputted.This result highlights the potential for discovering the Jurassic ores in Yangchun basin,and also provides important information for further discussion on the geodynamic settings of Qin-Hang metallogenic belt.

关 键 词：锆石U-Pb年龄 辉钼矿Re-Os测年 黑石岗铅锌铜矿床 留洞钨钼矿床 阳春盆地 

分 类 号：P618.4[天文地球—矿床学]