激发极化法在黔西北丫都铅锌矿床勘查中的应用

The application of induced polarization method in the Yadu lead-zinc deposit exploring in the northwest of Guizhou Province

丫都矿床位于丫都—蟒洞断裂中段,长期作为贵州省重要的铅锌矿产地,目前已经在F1下盘累计发现铅锌矿体10个,但是经过多年开采,目前地下400 m以上范围内资源已经枯竭。猪拱塘超大型铅锌矿的发现,证实了丫都—蟒洞断裂带500~900 m的深部具有形成大型矿体的地质条件。丫都铅锌矿外围深部具有良好的找矿前景,但是深部地质情况复杂,通过地表地质情况无法推测深部地质,如何快速圈定靶区和设计钻孔,物探工作必不可少。激发极化法是寻找金属矿最有效的方法之一,极电中梯测量可以有效缩小勘查的靶区,但是无法提供异常的地下空间展布;对称四极测深对500 m以浅的异常定位清晰,但是对深部较小异常的识别度不高,三极测深具有效率高、分辨率高和勘探深度大的优点,但是B极(∞极)施工要求较高。本文通过在丫都矿区外围开展激电中梯测量、对称四极测深和三极测深多装置探测工作显示,激电中梯测量获得11个异常,其中强异常5个,弱异常6个,对称四极测深和三极测深的结果乘以地区经验系数0.41后,与钻孔结果具有很好的对应关系,激电多装置联合探测在本区隐伏铅锌矿体的勘查中具有较好的效果,在黔西北地区开展此类找矿工作值得进一步试验和推广。

Yadu deposit,located in the middle of Yadu-Mangdong fault,has long been an important lead and zinc deposit in Guizhou Province.At present,10 lead and zinc deposits have been found in F1 footrol,but the resources above 400 m underground have been exhausted so far after exploitation of quite a few years.The discovery of Zhugongtang super large lead-zinc mine has proved that the deep area among 500 m to 900 m of Yadumangdong fault zone having the geological conditions to form large ore body.The periphery of the deep Yadu leadzinc mine has a good ore-prospecting future,but the complicated geological conditions in deep area contributes the failure to presume the deep geology through the surface geological condition,so geophysical work is necessary to delineate the target area and design drill hole rapidly.Induced polarization method is one of the most effective methods to discover metallic minerals.IP intermediate gradient can effectively narrow the range to explore the target area,but it cannot provide the underground space distribution.Symmetrical four-pole sounding has a clear positioning of 500 m above,but recognition to the tiny anomaly in the deep area is not high.Three-pole sounding has the advantages of high efficiency,high resolution and large exploration depth,but B pole (∞ pole) requires high construction.By applicating IP intermediate gradien,symmetrical four-pole sounding and three-pole sounding multi-device detection in the periphery of Yadu deposit,this paper has found 11 anomalies which are 5 strong anomalies and 6 weak anomalies in IP intermediate gradien,and multipling the result of symmetrical four-pole sounding and three-pole sounding by the regional experience coefficient 0.41 having a good correspondence with the drilling results.The IP multi-device joint detection has a good effect in exploring the hidden lead-zinc ore body and it deserves to be tested and generalized in the northwest of Guizhou Province.