广东金坑铜锡铅锌矿床成矿地质体研究

Research on the mineralization geological body in Jinkeng copper-tin-lead-zinc deposit,Guangdong

金坑铜锡铅锌矿区位于广东莲花山断裂带南西段,为中型热液充填交代铜锡铅锌矿床。文章在综合前人大量研究成果资料基础上,从成矿地质体与成矿的时空关系、物质来源方面进行系统分析研究。主微量元素与Hf同位素表明细粒黑云母花岗岩为高分异的I型花岗岩,并为成矿提供了巨量的物源和热源;硫、铅、氢氧稳定同位素证明成矿物质来源于深源岩浆,成矿流体以岩浆水为主并混入部分大气水,成矿环境为低盐度、中高温;岩浆岩LA-ICP-MS锆石U-Pb定年发现,细粒黑云母花岗岩成岩年龄为(141.0±0.3)Ma,矿床中与锡石毒砂共生的辉钼矿进行Re-Os同位素定年发现,成矿年龄为(141.3±1.0)Ma;由此初步认为该区成矿地质体为早白垩世细粒黑云母花岗岩。

Jinkeng copper-tin-lead-zinc property,located in the southwestern section of Lianhuashan fault zone,Guangdong Province,belongs to a medium-sized hydrothermal filling-metasomatism type deposit. Based on the former researches,this paper systematically analyzes and studies the time-space relationship between the mineralization geological body and mineralization,as well as the material source. The characteristics of major elements,trace elements and the zircon＇s Hf isotope show that the fine-grained biotite granite belongs to the highly fractionated I-type granite,which provides massive ore-forming materials and heat source for mineralization. The sulfur,lead,hydrogen and oxygen isotopic characteristics prove that the ore-forming material is derived from deep-seated magma,the ore-forming fluid is mainly composed of the magmatic water mixed with some atmospheric water,and the mineralization was occurred in a low salinity and medium to high temperature conditions. The LA-ICP-MS zircon U-Pb dating results of the magmatite show that the fine-grained biotite granite＇s diagenetic age is（ 141.0±0.3） Ma,and the Re-Os isotopic data of the molybdenite associated with cassiterite and arsenopyrite shows that the mineralization age is（ 141.0±1.0） Ma. Therefore,the paper preliminarily accounts that the early Cretaceous fine-grained biotite granite is most likely the mineralization geological body.