中条铜矿峪超大型斑岩铜矿床:地质、蚀变与成矿

山西中条山铜矿峪超大型斑岩铜矿床位于华北板块南部,秦岭造山带北侧,处在聚合板块活动大陆边缘的挤压-伸展的构造转换环境。矿区地层主要为古元古界"铜矿峪亚群",即火山-次火山岩,岩石经变质作用为绿片岩相和低角闪岩相。铜矿床在空间上与元古代钙碱性S型花岗斑(杂)岩体紧密共生,严格受火山机构控制。据辉钼矿Re-Os年龄,成矿时代为(2 108±32)Ma,是我国最古老的斑岩型铜矿床。铜矿床呈厚板状透镜体产出,矿石以细脉浸染状构造为主,有少量块状矿石产出。铜矿平均品位为0.68%,其中30%为富铜矿,并伴生钼、金。成矿热液主要源自深部地幔,也与地壳成分和天水渗入有关。因火山喷气和二次沸腾,在高侵位后,由分离作用形成碱质交代及石英绢云母化叠加红长石化的围岩蚀变,无面型环状分带特征。矿床成因推测为变火山热液斑岩型铜矿床。预测矿床深部可能赋存有岩浆房,找矿潜力很大。

Geology, alteration and metallogenesis of giant Tongkuangyu porphyry copper deposit in Zhongtiaoshan area

The giant Tongkuangyu porphyry copper deposit in Zhongtiaoshan area, shanxi province is located in the southern part of North China plate and/or the northern side of Qinling orogen where is a convergent active continent margin from compressional to extensional environment. The main stratum in the mining area is Tongkuangyu Subgroup of green schist of low amphibolite metamorphoded from volcanic and subvolcanic rocks. Spatially, the deposit is closely related to Proterozoic calc-alkaline S-type granite and is strictly controlled by volcanic apparatus. Re-Os age dating of molybdenite is (2 108±32)Ma and is the oldest porphyry copper deposit in China. Copper ore body occurs in thick tabular lens with veinlet-disseminated ore dominated and injected massive ore. The average grade is 0.68% Cu. Rich ore is about 30%. Ag and Mo are the by-products. Ore fluid is mainly derived from mantle and incorporated with crustal materials and meteoric water. Alkaline replacement and quartz + sericitization and the overprinting albitization occur at high level emplacement because of volcanic exhalation and secondary boiling. No planar ring structure is observed. The copper deposit is inferred a meta-volcanic hydrothermal porphyry copper deposit. Magma chamber is predicted and it is potential for further prospecting to depth of the deposit.