智利铁氧化物-铜-金矿床区域定位构造-矿田构造类型与特征

Types and Characteristics of Regional Tectonics and Ore-field Structures of Iron Oxide-Copper-Gold Deposits in Chile

智利铁氧化物铜金矿床形成于安第斯型活动大陆边缘中生代岩浆弧及弧后盆地,区域构造特征主要为岩浆侵入构造岩相带和阿塔卡玛断裂系统(AFZ),岩浆侵入构造及岩相分带控制矿田形成,AFZ断裂系统控制了矿化带和大型矿体产出。矿田构造主要有五种类型:火山构造;岩浆侵入构造+复式背斜;NS向平行韧性断裂带+岩浆侵入构造;走滑断裂弯曲节点由于转换扩张机制形成封闭的弧环形构造和热液角砾岩筒型。岩浆、断裂系统与成矿作用有密切的关系,关键因素是深成中酸性岩浆活动。通过研究提出了选区及勘查构造标志并认为矿田内构造蚀变岩相填图是一种有效的工作方法。

Iron oxide-copper-gold deposits in Chile were formed in the Mesozoic magmatic arc and back-arc basins on the Andes-type active continental margin.Regional tectonics are mainly characterized by magmatic intrusive faces and the Atacama fault system （AFZ）.Magmatic intrusive structures and litho faces zonation control the formation of ore fields and the AFZ fault system controls the occurrences of mineralized zones and large-scale ore bodies.Structures of ore fields include five types： volcanic structure,magmatic intrusive structure ＋ anticlinorium,NS trending parallel ductile fault zones ＋ magmatic intrusive structures,closed arc annular structures and hydrothermal breccia-pipe structures formed by transition and expansion of bending nodes of strike-slip faults.Magmatic systems and fault systems are closely related to mineralization,and plutonic intermediate-acid magmatic intrusive activities may be the key factor.Through studies,we suggested structural indicators for target selection and exploration and thought that the structure-altered faces mapping in ore field is one of the effective working methods.