胶东金矿“热隆伸展”成矿理论及其找矿意义

胶东地区近年来深部找矿取得重大进展,新探明金资源储量1 500多吨,发现了千吨级金矿田。研究指出:胶东不同类型金矿形成于同一地质时代,具有一致的物质来源,主要有2类赋矿围岩,受3种成矿构造带控制,有4种主要蚀变类型。"岩浆热隆、流体活动、伸展拆离"是导致胶东大规模金矿形成的三大关键要素,早白垩世地幔隆起引起壳幔同熔型伟德山花岗岩强烈活动,诱发大范围流体活化和广泛的伸展拆离构造,为金矿成矿提供了有利条件。据此,创建了胶东金矿"热隆-伸展"成矿理论,提出焦家式金矿不同于目前国际上公认的其他类型金矿。认为金矿在倾斜方向上主要沿控矿断裂倾角变化的平缓部位和陡、缓转折部位富集,构成"阶梯式"分布型式,在胶东地区已探明和开采的浅部金矿(第一台阶)之下还会有第二、第三个成矿台阶,胶东主要成矿区深部资源潜力巨大。

Thermal UpliftingExtension Oreforming Theory and Its Prospecting Significance in Jiaodong Gold Deposit

In recent years, deep prospecting has made great progress in Jiaodong area. More than 1500 tons gold mineral resources have been verified, and kiloton class gold fields have been found as well. It is pointed out that different types of gold deposits in Jiaodong area were formed in the same geological era, and had a consistent material sources. It has two main types of orebearing country rocks, and were controlled by three kinds of metallogenic tectonic zone and formed four main alteration types. The upwelling of hot magma, fluid activities and extensional detachment are three key elements for forming large scale gold deposits. In early Cretaceous, strong activities of Weideshan granite caused by mantle uplift had evoked a wide range of fluid activation and widely extensional detachment structure. It provided favorable conditions for gold mineralization. Accordingly, thermal upliftingextension oreforming theory has been established. It is said that Jiaojia type gold deposit is a new type gold deposit which has accepted by the world. Gold deposits are emplaced and enriched at the gentle angle fault segements and the break part from steep to gentle dip angles, and formed a ladder like distribution pattern. There are second and third metallogenic steps in the depth of proven and mining shallow gold deposits (first metallogenic step). The deepseated gold resources are with great potentiality in Jiaodong area.