胶莱盆地东北缘地区金矿特征及找矿方向

胶莱盆地东北缘地区,成矿条件优越,近年来发现了大中型金矿床多处,特别是辽上特大型金矿,引起众多专家学者关注。中生代侏罗纪至白垩纪,在扬子板块、伊佐奈岐板块以及印度洋板块联合作用下,形成了鲁东地区特殊的格局,胶莱盆地为该时段的产物。复杂的构造环境及两期次大的岩浆活动,为牧牛山地区金成矿作用提供了良好的储矿空间和成矿作用的动力及物质来源。古元古代荆山群含石墨的变质岩系和早白垩世形成的中基性脉岩,共同成为该地区金成矿重要的地球化学障。根据矿床显著的特点将牧牛山地区金矿分为蓬家夼式、土堆式、辽上式和宋家沟式四种类型,并建立了区域成矿模式,分析了成矿演化机制。指出了未来找矿方向。

Features and prospecting direction of the gold deposits in the northeastern margin of the Jiaolai Basin

On the northeastern margin of the Jiaolai basin, which has superior metallogenic conditions, several medium- and large-sized gold deposits have been discovered, especially the super-large Liaoshang deposit, which has attracted much attention. The distinctive geological setting of eastern Shandong developed under the joint action of the Yangtze, Izanagi and the Indian-Ocean plates from Jurassic to Cretaceous during which the Jiaolai Basin formed. The complicated tectonic environment and large-scale magmatic activities in two phases created the ore-forming space as well as the driving-material sources to gold mineralization in the Muniushan area. The geochemical barriers of this area comprise the graphite-bearing metamorphic rock series of the Paleoproterozoic Jingshan Group and the intermediate-basic Early-Cretaceous dike rocks. According to notable deposit features, the deposits in the Muniushan area can be classified to four types, namely the Pengjiakuang type, Tudui type, Liaoshang type and the Songjiagou type. The regional metallogenic models are accordingly established which permit to analyze the metallogenic evolution mechanism and to guide future prospecting.