摘要
胶莱盆地北缘宋家沟金矿分布众多与矿化相互交切的中基性脉岩,针对这些中基性脉岩开展了详细的LA-ICP-MS锆石U-Pb年代学、岩石学和地球化学研究。结果显示,中基性脉岩可以划分为成矿前和成矿后两类脉岩,岩石类型分别为辉绿岩和闪长岩,两者ΣREE含量均相对较高,成矿前脉岩LREE/HREE比值介于12.76~15.52,成矿后脉岩LREE/HREE比值为18.72,均表现出LREE相对富集,HREE相对亏损的特征。成矿前、后脉岩显著富集大离子亲石元素(Rb、Ba)和高场强元素(U、Th)等,亏损Nb、Ti等高场强元素,表现出受地壳物质混染的板内玄武岩特征。成矿前脉岩锆石U-Pb年龄介于518~802 Ma之间,属捕获锆石年龄,成矿后脉岩锆石U-Pb年龄为121±5 Ma,结合前人获得的莱阳群地层最大沉积年龄(130±2 Ma),认为宋家沟金矿床的形成时间为121~130 Ma。
There are many intermediate-basic dikes which intersect the mineralization belts in Songjiagou gold deposit.Detailed zircon LA-ICP-MS U-Pb geochronology,petrology and geochemistry have been carried out for these intermediate-basic dikes.The results show that the dykes can be divided into pre-metallogenic and post-metallogenic dykes,which consist of diabase and diorite respectively.TheΣREE contents of the two types of dykes are relatively high,the LREE/HREE ratio of the pre-metallogenic dike ranges from 12.76 to 15.52,and the LREE/HREE ratio of the post-metallogenic dike is 18.72.Both are characterized by relative enrichment of LREE and depletion of HREE.The pre-metallogenic and post-metallogenic dikes are enriched in large ion lithophile elements(Rb,Ba)and high field-strength elements(U,Th),but depleted in Nb,Ti and other high field-strength elements,which show the characteristics of intraplate basalts mixed with crustal materials.The zircon U-Pb ages of the pre-metallogenic dikes range from 518 to 802 Ma,which belongs to the captured zircons,while the zircon U--Pb age of the post-metallogenic dyke is(121±5)Ma.Combined with the maximum sedimentary age of Laiyang Group(130±2 Ma),it is concluded that the Songjiagou gold deposit was formed in 121~130 Ma.
作者
何泽宇
申俊峰
王来明
李国武
刘汉栋
张华锋
杜佰松
吴晋超
HE Ze-yu;SHEN Jun-feng;WANG Lai-ming;LI Guo-wu;LIU Han-dong;ZHANG Hua-feng;DU Bai-song;WU Jin-chao(School of the Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Shandong Institute of Geological Survey,Jinan 250013,China;Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China)
出处
《世界地质》
CAS
2020年第3期509-527,共19页
World Geology
基金
山东省地质勘查项目(鲁勘字[2018]19号)
国家重点研发计划“深地资源勘查开采”重点专项(2016YFC0600107)资助。
