辽东铀成矿带黄沟铀矿床地质特征及成因探讨

Geological Features and Ore Genesis of Huanggou Uranium Deposit in Eastern Liaoning Uranium Metallogenic Belt

连山关地区位于华北陆块铀成矿省辽东铀成矿带。笔者近几年在连山关地区开展铀矿普查找矿工作,通过黄沟铀矿床野外工作和室内研究,对其赋矿围岩的岩石学特征、地球化学特征、蚀变特征进行了细致研究。结果表明:赋矿围岩重熔混合岩有4种类型,主要特点是石英含量高,绿泥石含量变化大,石英与绿泥石的含量呈负相关;地球化学特征表明其主量元素具富Si、略富Al、富Na、富K和低Mg、低Ca特点;微量元素表现出富集Be、Mo、Pb、Y、Ba、La、Cu和亏损Co、Ni、Zn、Cr、Ti、V等特点;与铀关系密切的共生元素有Pb、Mo、V、Be;稀土元素具有明显的轻稀土元素富集和重稀土元素相对亏损等特征,具有较显著的Eu负异常;蚀变特征研究表明胶状黄铁矿化、绿泥石化、硅化与铀矿化关系密切。最后探讨了铀矿成因,并首次提出了重熔混合岩热液型铀矿。

The Lianshanguan area is located in the eastern Liaoning uranium metallogenic belt which belongs to the uranium metallogenetic province of the North China block.The reconnaissance and exploration on uranium deposit have been carried out in recent years to understand the mineralization characteristics and ore genesis.Based on the field investigation and laboratory studies,authors systematically studied petrologic,geochemical and wall-rock alteration characteristics of ore-hosting rocks.The results show that there are four types of anatexites in the ore-hosting rock series,which are characterized by the high silica content and the various content of chlorite.Moreover,there is a negativecorrelation between quartz and chlorite contents in the anatexite.The major element compositions in the ore-hosting rock show that it contains high SiO_2,Na_2O and K_2O,with slightly high Al_2O_3 and low MgO and CaO.Meanwhile,the trace elements show the enrichment of Be,Mo,Pb,Y,Ba,La,Cu and depletion of Co,Ni,Zn,Cr,Ti,V.These studies significantly demonstrate that such paragenetic elements as Pb,Mo,V,Be as are also closely related to uranium mineralization.Rare-earth element characteristics of samples are remarkable Eu negative anomalies,enriched in LREE（light rare earth elements）and depleted in HREE（heavy rare earth elements）.Colloidal pyritization,chloritization,silicification have close relationship with uranium mineralization.It＇s first proposed that there occur remelting migmatite-hydrothermal uranium deposits in the Lianshanguan area.