西昆仑大红柳滩-白龙山矿集区锂矿成矿特征与成矿规律初探

Geological characteristics and metallogenic regularity of lithium deposits in Dahongliutan-Bailongshan area,West Kunlun,China

大红柳滩-白龙山一带是西昆仑-喀喇昆仑花岗伟晶岩分布最为集中、稀有金属矿化最好的地区。通过多年的研究,本文对大红柳滩-白龙山矿集区21个锂多金属矿床进行了全面系统的梳理,将矿集区划分为大红柳滩矿田和白龙山矿田。矿集区内赋矿地层巴颜喀拉山群的形成时代为214~223Ma,花岗岩岩体年龄208~214Ma,不含矿伟晶岩年龄为210~213Ma,含矿伟晶岩年龄为206~213Ma,反映出稀有金属矿产与中生代岩浆岩具有耦合关系。成矿母岩(二云母花岗岩、黑云母花岗岩等)演化后期分异的含锂稀有金属伟晶岩脉沿着片理化带或构造薄弱地段就位成矿,成矿空间为距离中酸性岩体500~2000m的巴颜喀拉山群(或康西瓦岩群)地层中,符合构造-岩浆-层位“三位一体”控矿规律。同时,项目组将大红柳滩-白龙山矿集区从北至南划分为5个稀有金属矿化伟晶岩脉群带,分别为:阿克萨依稀有金属矿化伟晶岩脉群带、大红柳滩北稀有金属矿化伟晶岩脉群带、大红柳滩南稀有金属矿化伟晶岩脉群带、白龙山-雪凤岭锂矿化伟晶岩脉群带、俘虏沟-双牙锂矿化伟晶岩脉群带。其中,白龙山-雪凤岭锂矿化伟晶岩脉群带长约18km,俘虏沟-双牙锂矿化伟晶岩脉群带长约25km,这2个带呈南北对称分带。而俘虏沟-双牙锂矿化伟晶岩脉群带显示了巨大的找矿潜力,是下一步找矿的重要地段。

Dahongliutan-Bailongshan area is the most important rare-metal concentration area in the West Kunlun-Karakorum where there are most concentrated granite pegmatites and most developed rare-metal mineralization.This paper comprehensively and systematically surmurized 21 lithium polymetallic deposits in this area based on the achievements of years of research,and divided the ore concentration area into the Dahongliutan ore field and Bailongshan ore field.The ore-bearing strata in the ore concentration area is the Bayankela Group,whose formation age is 214~223Ma.Meanwhile,the age of granite rock mass is 208~214Ma,the ages of non-ore pegmatites and the ore-bearing pegmatites are 210~213Ma and 206~213Ma,respectively,which reflects the coupling relationship between the rare metal minerals and the Mesozoic magmatic rocks.The Li-bearing rare metal pegmatite veins formed by differentiation of the ore-forming parent rocks(biotite granite,biotite granite,etc.)in the late evolutionary stage are distributed in schistose zone or structurally weak area 500~2000m away from the intermediate-acid rock mass in the ore-forming strata of the Bayankala Group(or Kangxiwa Group),which conforms to the“trinity”ore-controlling law of structure-magma-horizon.At the same time,the project team divided the Dahongliutan-Bailongshan ore concentration area into five rare-metal mineralized pegmatite vein group belts from north to south,namely,the Aksayi rare-metal mineralized pegmatite vein group belt,the Dahongliutan north rare-metal mineralized pegmatite vein group belt,the Dahongliutan south rare-metal mineralized pegmatite vein group belt,the Bailongshan-Xuefengling lithium mineralized pegmatite vein group belt and the Fulugou-Shuangya lithium mineralized pegmatite vein group belt.Among them,the Bailongshan-Xuefengling and the Fulugou-Shuangya lithium mineralized pegmatite vein group belts are about 18km and 25km long,respectively,which are symmetrically zoned in the north and south of this area.The Fulugou-Shuangya lithium mineralized pegmatite vein group belt shows great prospecting potential,so it is an important belt for the next prospecting.