沂沭断裂带中段及西侧金矿成矿类型及成矿作用

Analysis of typical metallogenic types and mineralization of gold deposits in the Yishu fault belt,Shandong,China

探讨沂沭断裂带中段及其西侧金矿床的成矿类型及成矿作用,为金矿勘查提供依据。研究区金矿床类型包括岩浆期后热液型和绿岩带型,其中岩浆期后热液型又分为矽卡岩型、隐爆角砾岩型和潜火山热液石英脉型。选取铜井金铜矿床和化马湾金矿床作为岩浆期后热液型和绿岩带型金矿类型的典型代表,从矿床的地质特征、矿体特征及成矿作用等方面进行分析。研究表明岩浆作用是岩浆期后热液型矿床成矿主导因素,控矿构造是其空间展布形式;区域变质作用是绿岩带型金矿成矿的主导因素。该地区寻找与燕山期侵入杂岩体有关的火山热液型金矿床是下一步找矿的重要方向,其中次火山侵入杂岩体分布区、爆破角砾岩筒、断裂构造交汇部位以及化探异常与地质标志相对应地段均是找矿勘查的方向。

Metallogenic types and gold mineralization along the middle part of Yishu fault belt are studied so as to provide more theoretical basis and prospecting clues for gold exploration in this area. Two types of gold deposits occur in the study area, including post magmatic hydrothermal type and greenstone belt type. The former can be subdivided into the contact metasomatic type, cryptoexplosion breccia type and submarine volcano hydrothermal quartz vein type respectively. The Tongjing gold-copper deposit and Huamawan gold deposit are selected as a typical representative of the post magmatic hydrothermal type and greenstone belt type to study their geological features, orebody characters and mineralization. It shows that magmatism is the dominant factor to control the formation of post magmatic hydrothermal type deposits and the ore-controlling structures determine spatial distribution of ore. Regional metamorphism is the leading factor in gold mineralization to the greenstone belt type. The prospecting direction for future work is to find volcano hydrothermal gold deposit related to intrusive complex of Yanshan period, and volcano intrusive complex, explosion breccia and fault intersections are the key to exploration targets.