辽东地区金矿床类型、成矿特征及找矿潜力

辽东地区是我国重要的金矿集区之一,中生代构造、岩浆活动强烈,并伴生强烈的金成矿作用。根据金矿床时空分布及成矿特征,将辽东地区划分为三个金矿集区:青城子、五龙、猫岭。矿集区内金矿包括石英脉型金矿和蚀变岩型金矿这两种类型,并分别受高角度断裂和低角度断裂构造体系控制。辽东地区金矿成矿时代主要为早白垩世,少量早侏罗世。已有H-O同位素、成矿流体及地质研究表明:(1)区内金成矿与中生代岩浆活动有关、受断裂构造控制,并以强烈硅化-绢云母化为特征标志;(2)区内金矿床属于岩浆热液型矿床;(3)充填作用和混合作用可能是辽东地区金矿床成矿物质沉淀的机制。辽东地区金矿成矿系统按其产出环境及特点,可分为两个亚系统:产于中生代花岗质岩体内岩浆热液金成矿系统(五龙式)及产于古元古代变质岩中岩浆热液金成矿系统(青城子式、猫岭式)。结合区域找矿进展和近期研究工作,建立了辽东地区金矿找矿预测地质模型,认为本区具有与胶东地区相似的金矿成矿条件,成矿潜力巨大,研究工作对区域矿产勘查部署工作有指导意义。

The metallogenic characteristics and exploring ore potential of the gold deposits in eastern Liaoning Province

The eastern Liaoning Province is one of the most important Au ore-concentrated areas in China. The Mesozoic tectonic and magmatic activities developed in eastern Liaoning Province accompanied with the intense gold mineralization. According to the time-space distributions and metallogenic characteristics of the gold deposits, the eastern Liaoning Province can be divided into three gold ore-concentrated districts:the Qingchengzi, the Wulong and the Maoliang districts. Gold deposits includes two gold mineralization types:quartz vein type and altered rock type. The quartz vein type gold deposits are controlled by the high-angle fault system, and the altered rock type gold deposits are controlled by the low-angle fault system. The ore-forming epochs of the gold mineralization in eastern Liaoning Province are major Early Cretaceous with minor Early Jurassic. Combing with the H-O isotopes, ore-forming fluids and geological studies, we think that:(1) the gold mineralization is related to the Mesozoic magmatic activities, and is characterized by the strong silicification and sericitization; (2) the gold deposits belong to the magmatic hydrothermal gold deposit; and (3) the filling and mixing might be the major depositional mechanism of the gold deposits. The gold hydrothermal ore-forming system of the eastern Liaoning Province is divided into two sub-ore-forming systems by the occurrence environment and features of the gold deposits:the gold ore-forming system hosted in Mesozoic granitoids (the Wulong type) and the gold ore-forming system hosted in Paleoproterozoic metamorphic rocks (the Qingchengzi type and Maoling type). By integrating the progress of the prospecting and recent studies, we set up the geological model of prospecting and prediction for gold deposits in Liaodong area, and proposed that eastern Liaodong area has the similar gold ore-forming conditions with the Jiaodong area, and therefore, the eastern Liaodong area also has huge metallogenic potentiality. The studied works has guiding significance for the regional mineral prospecting.