煎茶岭含钴硫化镍矿床成矿作用研究

The study on ore-forming process of Jianchaling large cobalt-bearing nickel ore deposit

对煎茶岭硫化镍矿床地质背景、岩体及矿石的地质地球化学特征进行了研究。结果表明:煎茶岭大型含钴硫化镍矿床的形成与镁质超基性岩体密切相关且具有特殊性,其成矿物质主要来源于深部岩浆;源自上地幔局部熔融的母岩浆,在通过上地幔岩石圈上升侵位过程中,就地发生硫化物熔离作用和硫化作用,形成早期的富镍矿体和部分贫矿石;稍后的蛇纹石化作用是形成该矿床中后期富镍矿体的主要原因;元古代岩浆作用、硫化作用和蛇纹石化作用是煎茶岭镍矿床主要的成矿作用方式;成矿机制是岩浆分结+硫化熔离+蛇纹石化。认为该镍矿床PGE含量较低且贫铜,Cu/Ni值极低,成因上属岩浆型矿床,但后期存在热液成矿作用。

The geological background of Jianchaling nickel sulfide deposit,and geological geochemical characeristics of its ore and rockbody have been studied.It is concluded that the formation of Jianchaling large nickel sulfide deposit is nearly related with the magnesian ultrabasic rockbody,which is its speciality,and its oreforming is mainly derived from magma in deepth.Parent magma which originated from partial melting of the upper mantle generated sulfide melting segregation and sulfurization to form early rich nickel ore bodies and some poor ore during rifting through the upper mantle lithosphere to emplace.Late serpentinization are the main reason to form latter rich nickel ore bodies.Proterozoic magmatism,sulfurization,and serpentinization are the main metallogenic ways of the nickel sulfide deposit.The metallogenic mechanism includes magmatic fractionationcrystallization, sulfurizationsegregation,and serpentinization.The nickel deposit has a low content of PGE and copper,with very low Cu/Ni ratio,it should belong to magma type ore deposit,also exist late hydrthermal fluid mineralization.