皖南东至查册桥金矿岩浆岩锆石U-Pb年龄及其成矿意义  

U-Pb Zircon Geochronology of Magmatic Rocks from the Zhaceqiao Gold Deposit in the Dongzhi Area,South Anhui Province and its Metallogenic Significance

作　　者：聂张星[1] 石磊[1] 古黄玲[2] 钱祥[1] 胥飞[1] 杨金龙[1] 杨晓勇[2] 

机构地区：[1]安徽省地质矿产勘查局311地质队,安徽安庆246003 [2]地球和空间科学学院,中国科学技术大学,合肥230026

出　　处：《地质学报》2016年第6期1146-1166,共21页Acta Geologica Sinica

基　　金：安徽省国土资源厅《安徽省东至县查册桥-西峰尖金铜多金属矿成矿条件及控矿因素研究》(2012-1-28);安徽省地质矿产勘查局科技项目《安徽省东至县赵家岭金矿成矿条件与近代矿因素研究》(KJ2014-04);国家自然科学基金(41372087)共同资助的成果

摘　　要：安徽省东至县查册桥金矿是近年来在江南过渡带上新发现的具一定规模的金矿床,包括多个矿段（点）。矿体受NNE向、NE向及近EW向断裂控制。矿化类型以高硫浅成低温热液型金（锑）矿化为主。其矿床的形成与燕山期岩浆活动有密切的时空和成因联系,区内岩浆岩主要有花岗斑岩、花岗闪长岩、花岗闪长斑岩、闪长玢岩及英安玢岩。本文通过对区内岩浆岩LA-ICP-MS锆石U-Pb测年,确定了区内岩体成岩时间晚侏罗世到早白垩世之间,花岗闪长斑岩在143-148Ma侵位,花岗闪长岩侵位年龄为145Ma,闪长玢岩略晚（142Ma）,金多金属矿化稍晚,且持续时间较长。矿区岩浆岩中均发育大量继承锆石,反映有大量成岩物质来源于古老地壳基底,与岩浆岩的成因类型（壳幔同熔型）对应,并与所处的江南过渡带的大地构造位置（江南过渡带）及地质构造发展历史有关。（2522±72Ma）古老的继承锆石年龄,指示本区存在太古代基底物质;较为广泛的新元古代600-1000Ma继承锆石年龄数据,反映了江南过渡带晋宁期扬子陆块与华夏陆块碰撞造山过程所形成的物质再循环到本区燕山期岩浆活动与成矿过程中去。查册桥金矿成矿作用与岩浆期后大规模热液蚀变相联系,并在持续的岩浆活动和热液作用下富集和成矿。综合成矿地质背景、成岩成矿年代学,可以认为,查册桥金矿是一个受断裂构造控制的、与燕山期中酸性岩浆作用密切相关的浅成低温热液型金矿床。The Zhaceqiao gold deposit in the Dongzhi area of Anhui Province is a recently discovered gold deposit in the Jiangnan transition belt,which contains a certain amount of gold reserves and multiple ore occurrences or prospects.The orebodies are controlled mainly by NNE-,NE-and near EW-trending faulting.The mineralization type is dominantly high S epithermal gold（Sb）deposit.The formation of the deposit has close spatio-tempero relationship with the Yanshanian magmatic activity.Magmatic rocks in the mining area include granite porphyry,granodiorite,granodiorite-porphyry,diorite porphyrite and porphyritic dacite.LA-ICP-MS U-Pb zircon dating for igneous rocks indicates that the Zhaceqiao intrusions was emplaced between the late Jurassic and early Cretaceous,with granodiorite porphyry in the 143-148Ma,granodiorite in 145 Ma,and diorite porphyrite in the late（142Ma）.But the gold-polymetallic mineralization occurred later than that of the magmatic rocks and lasted for long period.A large amount of inherited zircons developed in this area reflects that the ore-forming material might derive from the ancient crustal basement and corresponds to natures of magmatic rocks（crust-mantle syntexitype）,indicating that it might relate to the unique tectonic position of the Jiangnan transition zone and development history of geology tectonic.Old inherited zircon U-Pb dating of（2522±73Ma）indicates Archean basement materials;The extensive Neoproterozoic inherited zircon ages of 600-1000Ma reflects the materials formed by the collision orogenic process between Yangtze block and Cathaysia block in Jinningian period was recycled to the Yanshanian magmatic activity and mineralization process.The Zhaceqiao gold mineralization is closely related to post-magmatic large-scale hydrothermal alteration,during which the gold was enriched and deposited under the continuous magmatic activity and hydrothermal action.Combined with metallogenic geological background and geochronological data,it can be concluded that the Zhaceqiao gold

关 键 词：锆石LA-ICP-MS U-PB年龄 太古代基底 查册桥金矿 东至 皖南 

分 类 号：P618.51[天文地球—矿床学]