赣杭铀成矿带中段鹅公山火山盆地铀矿控矿因素分析

Analysis on Ore Controlling Factors of Uranium Deposits in Egongshan Volcanic Basin,Middle Ganhang Uranium Metallogenic Belt

鹅公山火山盆地位于赣杭铀成矿带中段,已探明林家、双头埠、新安埠3个铀矿床及众多铀矿(化)点。文章对盆地内铀矿控矿因素进行分析,认为铀矿化受地层、构造、次火山岩、中基性脉岩等联合控制。上侏罗统和下白垩统火山-沉积岩及下二叠统安洲组、栖霞组灰岩是主要的赋矿岩层;基底近EW向、NE向断裂是导矿构造,铀矿床定位于两者的复合部位;NW向断裂、推(滑)覆断裂、层间破碎带是主要的含矿构造,也是流体中成矿物质沉淀富集的有利场所。盆地东部以NW向断裂控矿为主,西部以推(滑)覆断裂为主;次火山岩及中基性脉岩的侵位不仅为铀成矿提供了热源和流体来源,还提供了有利的矿化剂、还原剂。综合分析认为:盆地东部以NW向断裂及中基性脉岩为主要找矿线索,西部则以推(滑)覆断裂为主要找矿方向。

Egongshan volcanic basin is located in the middle Ganhang uranium metallogenic belt,which have produced Linjia,Shuangtoubu,Xinanbu three uranium deposits and many ore（mineralized）occurreces.The study of uranium ore controlling factors shew that mineralization was controlled by the joint of the stratum,structure,the volcanic rocks and intermediate-basic dike.Volcano-sedimentary rocks in Late Jurassic-Early Cretaceous period and Early Permian Anzhou,Qixia group limestone are the main ore layer.EW and NE basement rift are major ore-control structure,the composite parts positioning uranium ore deposits.The NW fracture,inter-formation fracture zone,nappe and detachment fault are the main ore-bearing structures,which are good places for rich uranium fluid flowing and ore-forming material concentration.The NW fractures are ore-controlling structures in the east of basin,the nappe and detachment faults are ore-controlling structures in the west.The volcanic rocks and intermediate-basic dike are not only the uranium mineralization source of heat and fluid,but also are favorable mineralizer and reducer.Comprehensive analysis suggest that the NW fracture and intermediate-basic dike are the main prospecting clues in the eastern of basin and the nappe and detachment faults are the main prospecting criteria in the west.