CSAMT测深和重力测量技术在哈密白山钼矿深部找矿和远景评价中的应用

The application of CSAMT and GS on prospecting and evaluation in Baishan molybdenum deposit,Hami,Xinjiang

针对隐伏金属矿产勘查的深度逐渐加大、勘查区逐渐向工作程度相对较低、情况更加复杂的山区转移,常规的单一的物探方法在勘探深度及精度等方面都已经无法满足目前勘查的需要.本文提出可控源音频大地电磁测深法(CSAMT)与重力测量(GS)的技术组合,并将其运用于新疆哈密白山钼矿勘查实践中.哈密白山钼矿深孔在1400m以下的深部验证了隐伏花岗岩体的存在,证实白山钼矿属于斑岩型钼矿.岩体顶盖碎裂角岩化带是热接触变质的产物,含矿物质来源于深部岩浆热液.CSAMT测深和重力测量能较好地反映隐伏花岗岩体的就位空间和大致的侵入界线,深部隐伏花岗岩显示高阻高重力异常,中低阻异常围绕高阻高重异常周边分布,钻探验证在高阻异常顶部200～2500Ωm中低阻异常区间对应的是钼矿层位.依据钻探工程对隐伏花岗岩和钼矿层的控制,对应CSAMT测深剖面似电阻率等值线区间,大致推断隐伏花岗岩的侵入顶界和定位预测深部的钼矿赋存空间.白山钼矿的预测远景资源量可达200万吨以上.

Along with the increasing exploration depth of concealed metal deposits, and exploration areas gradually transferring to relatively poorly surveyed and complex mountainous districts, single geophysical methods are unable to meet the present exploration needs in depth and precision. To solve this problem, this paper proposes a combinedmethod of CSAMT and GS technology, and has applied it to the survey of concealed molybdenum deposit in the Baishan, Hami, Xiniiang. During the Deep Drilling Activity, there exsits a hidden granite body in 1400 meters deep of Hami Baishan molybdenum mine to be discovered, it confirmed that Baishan molybdenum mine is a porphyry molybdenum mine. Cataclastic hornfelsed zone in the coping granite are product of heat contact metamorphism, the ore materials are mainly derived from deep magma hydrothermal solution. The CSAMT and Gravity Survey were able to reflect the space and intrusive boundary in rough of buried granite body very well, deep hidden granite showed high-resistivity and high-gravity anomaly and the low-resistivity anomaly distributied around them, drilling verified that 200-2500 low-resistivity anomaly range at top of high-resistivity corresponded to the molybdenum ore horizon, According to the control of drilling works on buried granite and molybdenum ore horizon, corresponding resistivity contour lines interval of CSAMT, we inferred approximately the top intrusion boundary of buried granite and located and predicted the deep molybdenum ore forming space. Potential reserve prediction of Baishan molybdenum mine could be more than 2 million tons.