铜陵矿集区清水塘铜矿成矿年代学特征及其地质意义  

Ore-forming Age of Qingshuitang Copper Deposit in Tongling Metallogenic District and its Significance

作　　者：蔡杨[1,2] 杜建国 施珂[1,2] 万秋 董婷婷 CAI Yang;DU Jianguo;SHI Ke;WAN Qiu;DONG Tingting(Geological Survey of Anhui Province,Hefei 230001,Anhui,China;Technology Innovation Center of Coverage Area Deep Resource Exploration Engineering,MNR,Hefei 230001,Anhui,China)

机构地区：[1]安徽省地质调查院,安徽合肥230001 [2]自然资源部覆盖区深部资源勘查工程技术创新中心,安徽合肥230001

出　　处：《大地构造与成矿学》2020年第5期958-970,共13页Geotectonica et Metallogenia

基　　金：安徽省重点研究与开发计划(201904a07020077);安徽省国土资源科技项目(2016-k-3)联合资助。

摘　　要：铜陵矿集区是中国东部重要的铜金多金属成矿带,清水塘铜矿床是矿集区内典型的矽卡岩型铜矿床,位于凤凰山矿田内。本文对清水塘铜矿床中的辉钼矿进行了Re-Os同位素测年,显示辉钼矿的Re-Os同位素模式年龄范围为140.9±1.1 Ma^141.4±1.1 Ma,加权平均年龄为141.3±0.7 Ma,对应的等时线年龄为142.0±1.7 Ma,与新屋里岩体花岗闪长岩的年龄(141.3±1.3 Ma)接近,表明清水塘铜矿床与花岗闪长岩具有密切的成因联系,属于早白垩世岩浆–成矿作用的产物。辉钼矿Re的含量为2.23×10^−6~4.94×10^−6,表明成矿物质可能以壳源为主。铜陵地区具有多期成矿的特点,其中135~145 Ma是铜金成矿作用的高峰期。清水塘铜矿的成岩成矿作用与铜陵矿集区中生代大规模铜金成矿作用在时间上一致,具有统一的地球动力学背景,形成于由挤压到伸展转化的构造背景下。The Tongling metallogenic district is one of the important copper-gold-polymetallic ore belts in East China.The Qingshuitang copper deposit is a typical skarn-type copper deposit in the district,which is located in the Fenghuangshan orefield.Re-Os dating of molybdenite from the Qingshuitang copper deposit has been carried out to constrain the age of mineralization.The molybdenite samples have Re-Os model ages range from 140.9±1.1 Ma to 141.4±1.1 Ma,with an average age of 141.3±0.7 Ma.The Re-Os isochron age of 142.0±1.7 Ma is consistent with the zircon U-Pb age(141.3±1.3 Ma)of the Xinwuli granodiorite.The dating results indicate that the Qingshuitang copper deposit is genetically related to the Early Cretaceous Xinwuli granodiorite.The Re contents of molybdenite range from 2.23×10^−6 to 4.94×10^−6,indicative of a crustal source.Formation of the Qingshuitang copper deposit is consistent with the peak period(135 to 145 Ma)of copper-gold polymetallic mineralization in the Tongling metallogenic district.Therefore,the Qingshuitang copper deposit was formed under a tectonic transition environment from compression to extension.

关 键 词：铜陵地区 清水塘铜矿 辉钼矿RE-OS年龄 动力学背景 

分 类 号：P67[天文地球—海洋地质]