胶东西北部重要金成矿断裂带特征

Features of Major Gold Metallogenic Fracture Belt in Northwestern Jiaodong

胶东地区已累计探明金资源储量超过4 500 t,成为世界级重要的金矿集区之一。该地区发育蚀变岩型、石英脉型和层间破碎带型金矿,受区域主干断裂、次级断裂及盆地边滑动断裂的控制,其中蚀变岩型金矿是区内最重要的金矿类型。胶东西北部已发现的超大型金矿均受胶西北三山岛、焦家和招平3条主干断裂的控制,3条主干断裂控制的金矿资源量已超过3 300 t。这3条主干断裂阶段活动明显:早阶段发生韧性剪切变形作用,形成韧性剪切带,由糜棱岩和糜棱岩化岩石组成;中阶段发生脆性变形作用,形成碎裂岩(化)带;晚阶段为挤压变形,形成断层泥。金矿成矿与中期脆性变形密切相关,金矿化赋存于主干断裂带中碎裂(角砾)岩带发育部位。研究表明,3条主干断裂深部仍具有巨大的找矿潜力。

Over 4 500 tons of gold reserves have been proved in Jiaodong area,and Jiaodong area has become one of the important world-class gold cluster areas.Altered rock type,quartz vein type and interlayer fracture zone type gold ores are the major gold ore type in Jiaodong area,these gold ores are controlled by major regional faults,secondary faults and interlayer slide faults.Altered rock type gold deposit is the most important gold deposit in Jiaodong area.The discovery super-large gold deposits are controlled by Sanshandao,Jiaojia and Zhaoping faults,over 3 300 tons gold reserves have been proved in these three major faults.Sanshandao,Jiaojia and Zhaoping faults are characterized by poly-stage activities:early stage ductile shear deformation characterized by mylonite and mylonitic rocks,middle stage brittle deformation characterized by the cataclastic rock(or breccia),and late stage compressional deformation characterized by the fault gouge.The gold mineralization in Jiaodong area is closely related to the middle stage brittle deformation,and the gold mineralization occur within the catclastic(breccia)zones.The research shows that the three major faults still have huge exploration ore potential.