焦家断裂带对成矿的制约

焦家金矿田内矿体稳定、规模巨大,勘查深度已超过2000m,探获金金属量已超千吨,是我国重要的金矿产地。矿体严格受NNE向焦家断裂带控制,产状与构造面产状基本一致。从断层岩岩性和构造面表面形态入手,构建了三维构造模型,研究了断层面形态和断层岩岩性差异对成矿的约束作用。系统收集焦家金矿田内500个钻孔地质资料,通过二维三维相结合方式,发现断层岩岩性从浅部向深部发生明显变化,由断层泥渐变为糜棱岩,而上盘矿体数量和蚀变分带也随着断层岩的改变发生明显变化。对构造面进行表面坡度分析,发现矿体主要赋存在表面坡度较小部位,且沿倾向上表面坡度由陡急速变缓部位易于形成厚大矿体。

Constraints of Jiaojia Fault Zone on Mineralization

The orebody in Jiaojia gold ore field is stable and huge in scale. The exploration depth has exceeded to 2000m, and the amount of detected gold metal has exceeded to 1000t. It is an important gold deposit in China. The orebody is strictly controlled by Jiaojia fault zone with the trend of NNE. The orebody attitude coincides basically with structural plane. Based on the lithology of fault rocks and the surface morphology of tectonic planes, threedimensional structural model has been set up to study the constranits of fault stratigraphic morphology and fault rocks lithology to mineralization. Geological data of 500 boreholes in Jiaojia gold ore field have been systematically collected. Through the combination of twodimensional and threedimensional methods, it is found that the lithology of fault rocks changed significantly from fault gouge to mylonite with the depth gradually deeper. The number of ore body and alteration zone on the fault hanging wall also changed significantly with the lithology of fault rocks. Based on the analysis of the surface slope of the structural planes, it is found that the ore bodies are mainly located in the part of small surface slope, and the thick orebodies occur easily in the turning point, where the surface slope change sharply from steep to gentle.