The development of Tongchuan City,Shaanxi Province,located in the northwestern region of China,is restricted by water resources.The direct current resistivity and induced polarization sounding methods are typically ap...The development of Tongchuan City,Shaanxi Province,located in the northwestern region of China,is restricted by water resources.The direct current resistivity and induced polarization sounding methods are typically applied in finding urban groundwater.These methods,however,are not effective due to their complicated topography and geological conditions.The application practice shows that the audio magnetotelluric(AMT)method has a large depth of exploration,high work effi ciency,and high lateral resolution.To investigate the distribution of groundwater resources,we deployed three audio-frequency magnetotelluric profiles in the city area.The impedance tensor information of AMT data is obtained using SSMT2000.AMT data dimension analysis reveals that the two-dimensional structural features of the observation area are obvious.The main structure of the observation area is about 45°northeast,as indicated by structural trend analysis.A shallow two-dimensional electrical profile of 1 km in Tongchuan City is obtained by two-dimensional nonlinear conjugate gradient inversion.Finally,combined with regional geological information,the geological structure characteristics reflected by the electrical profile were obtained along with the detailed characteristics of water-rich structures in the area.The infl uence of the structure on the groundwater distribution was analyzed,and the water-rich areas were identifi ed.This work contributes to the prospective development of Tongchuan City.展开更多
The results of recent mineral exploration in the Yuele lead-zinc mining area of Daguan County, northeastern Yunnan province, showed that there are much early Paleozoic strata under thick late Paleozoic strata in north...The results of recent mineral exploration in the Yuele lead-zinc mining area of Daguan County, northeastern Yunnan province, showed that there are much early Paleozoic strata under thick late Paleozoic strata in northeastern Yunnan province, where developed some hidden salt structures (SSs), often with lead-zinc polymetallic mineralization varying degrees along the tension torsional fault (belts) or fracture (joint). The ore-bodies belong to the epigenetic hydrothermal filling vein-type deposit, and the prospecting potential is great. In this area, the superficial mineralization information displayed clear, but the deep mineralization is unknown, so the exploration work is restricted. The audio-megnetotelluric (AMT) surveying is an advantageous method to characterize the size, resistivity and skin depth of the polarizable mineral deposit concealed beneath thick overburden. This paper presents the surveying results using AMT method to evaluate the concealed lead-zinc mineralization in Yuele lead-zinc ore field, Daguancounty, NE Yunnan province, China. After comparing the interpretation result of AMT surveying data with the geological data and the drilling data, it is found that there is some distinct difference in resistivity and polarizable between ore-bodies hosted strata, upper strata and gypsum strata. The results show that AMT method is helpful to identify lead-zinc mineralization under this geological condition.展开更多
基金This work is financially supported by the National 863 Program(No:2014AA06A602)National Natural Science Foundation of China(Nos.41404111,41904076 and 42074084).
文摘The development of Tongchuan City,Shaanxi Province,located in the northwestern region of China,is restricted by water resources.The direct current resistivity and induced polarization sounding methods are typically applied in finding urban groundwater.These methods,however,are not effective due to their complicated topography and geological conditions.The application practice shows that the audio magnetotelluric(AMT)method has a large depth of exploration,high work effi ciency,and high lateral resolution.To investigate the distribution of groundwater resources,we deployed three audio-frequency magnetotelluric profiles in the city area.The impedance tensor information of AMT data is obtained using SSMT2000.AMT data dimension analysis reveals that the two-dimensional structural features of the observation area are obvious.The main structure of the observation area is about 45°northeast,as indicated by structural trend analysis.A shallow two-dimensional electrical profile of 1 km in Tongchuan City is obtained by two-dimensional nonlinear conjugate gradient inversion.Finally,combined with regional geological information,the geological structure characteristics reflected by the electrical profile were obtained along with the detailed characteristics of water-rich structures in the area.The infl uence of the structure on the groundwater distribution was analyzed,and the water-rich areas were identifi ed.This work contributes to the prospective development of Tongchuan City.
文摘The results of recent mineral exploration in the Yuele lead-zinc mining area of Daguan County, northeastern Yunnan province, showed that there are much early Paleozoic strata under thick late Paleozoic strata in northeastern Yunnan province, where developed some hidden salt structures (SSs), often with lead-zinc polymetallic mineralization varying degrees along the tension torsional fault (belts) or fracture (joint). The ore-bodies belong to the epigenetic hydrothermal filling vein-type deposit, and the prospecting potential is great. In this area, the superficial mineralization information displayed clear, but the deep mineralization is unknown, so the exploration work is restricted. The audio-megnetotelluric (AMT) surveying is an advantageous method to characterize the size, resistivity and skin depth of the polarizable mineral deposit concealed beneath thick overburden. This paper presents the surveying results using AMT method to evaluate the concealed lead-zinc mineralization in Yuele lead-zinc ore field, Daguancounty, NE Yunnan province, China. After comparing the interpretation result of AMT surveying data with the geological data and the drilling data, it is found that there is some distinct difference in resistivity and polarizable between ore-bodies hosted strata, upper strata and gypsum strata. The results show that AMT method is helpful to identify lead-zinc mineralization under this geological condition.
