LU Mao¹, HUANG Kai¹, JIANG Hai-min¹, ZENG Dao-guo¹, PU Qing-long¹, TANG Yong-yong²

(1. Institute of Geology and Mineral Resource Exploration, Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou，Guiyang 550005, China;
2. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China)

Abstract: The exploration of lead-zinc ore in the Northwestern Guizhou has been currently focused on the concealed Pb-Zn resources in depth of the area. Whether found the geophysical anomalies, caused by the lead-zinc mineralization, could be detected or discovered at depth of 300－1000 m or even deeper place in this area by using normal geophysical prospecting methods is an important research topic which is currently considered by many geophysical prospecting workers in Guizhou Province. Whether the problem could be solved or not is of great practical significance to the present and future prospecting work of Pb-Zn resources in this area. Based on the theory of time-domain induced polarization sounding method, we have believed that under the condition of better coupling between the parameters, including high power, suitable device, and delay timing, and concealed orebodies in depth, the anomalies caused by lead-zinc orebodies in depth of higher than 300 m can be found. In order to verify the feasibility of this method applied to the mineral exploration in depth, we have carried out the high-power induced polarization sounding test by using different devices and different times of power supply cycles on the boreholes of known orebodies in the Xixiangou lead-zinc deposit in Hezhang of the Northwestern Guizhou in this paper. The test results show that good anomalies, caused by Pb-Zn orebodies in depth, can be outlined with the data obtained by using the encryption unequal ratio device measurement method of the IP ladder under conditions including the suitable distance of electrodes, the power supply cycle time of 32s, the delay time of 200 ms, and the sampling width of 200 ms. The locations of IP anomalies inverted by using data of the isometric symmetrical quadrupole sounding measurement of IP under MN/AB=1/10 and depth correction coefficient of 0.41 can be accurately determined. Therefore, this method is worth to be promoted for applying into the exploration of Pb-Zn resoces in this area.

Keywords: The time-domain induced polarization method; encryption unequal ratio device; depth correction; the Xixiangou lead-zinc deposit

ACTA MINERALOGICA SINICA Vol. 40, No.4, 2020, page 502-509