矿源系统地质-地球化学例析

GEOLOGICAL AND GEOCHEMICAL STUDY ON ORE SOURCE SYSTEM OF JIAODONG GOLD ORE DEPOSIT CLUSTER, SHANDONG,CHINA

以胶东金矿集中区矿源系统为例 ,运用现代分形理论、数学地质和模拟实验等方法 ,探索矿质来源和富集过程。结果表明 ,胶东群正变质岩的原岩——太古代拉斑玄武岩为初始矿源岩 ;太古代—元古代胶东群、荆山群和粉子山群变质岩为中间矿源岩 ;中生代剪切重熔岩浆岩——玲珑型花岗岩和郭家岭型花岗岩是成矿物质的直接提供者 ;郭家岭型花岗岩可能既为金成矿提供物质来源 ,又起到“热机”作用。金的成矿作用是在古老地幔分异出的太古代拉斑玄武岩基础上 ,经韧性剪切→区域变质→岩浆重熔等构造热动力作用逐步富集的过程 。

Taking the Jiaodong gold ore deposit cluster for example,based on geological analysis, modern fractal theory,mathematics geology,modeling experiment and computer simulation,a through study on ore source system was made. The results show that:(1)Ore source system consists of initial ore source rock,intermediate ore source rock and direct ore source rock.The Jiaodong Group,the Jingshan Group or the Fenzishan Group and Linglong type granites provided materials for mineralization.While Guojiaoling type granites may not only provide ore forming materials partly,but also play a role as “hot engine”.There is little probability for the Penglai Group and Luanjiahe type granites to provide ore forming materials.(2)Gold mineralization is a complex ploy stages and ploy sources process.It started with Archean tholeiites fractionated from the old mantle and underwent shear,regional metamorphism and anatexis.Gold was enriched gradually in those tectonic thermal dynamic processes.Mesozoic shear remelting granites provided ore forming materials directly.(3)Remobilization,migration and enrichment of ore forming material generated by compression extensional shear tectonic activities are the main cause of mineralization.The understanding will provide a new way for the study of gold origin,perfecting of genetic classifications of gold deposits and setting up metallogenetic model. It shows the direction of ore prospecting.