| The exploration areas in Dongshan Town, Shidian County, Yunnan Province is mainly composed of lead-zinc mine. After years of exploitation, a batch of lead-zinc ore of outcrop or near-surface have been found. So the following step is to find the deep concealed deposits. Because most of exploration areas’ground surface is composed of the highly weathered rocks (dolomite and limestone), lack of direct prospecting criteria, so it is difficult to find the deep concealed deposits.According to the results of earlier geology, geophysics and geochemistry exploration, superadd the remote sensing data, some partly outcropped and shallowly buried industrial orebody in the east of exploration areas have been found, however, there is not breakthrough in the west. By analysing the former data of conventional geophysical and geochemical methods, the possibility of finding the shallow orebody is small, so the focal point of exploration is the search for deep buried ore body.With support of the project of The National Natural Science Foundation of China: field of geogas on concealed geological and fracture research (project Numbers:41074094),and the key project of natural science of education ministry of Sichuan province "research of geogas field on the concealed metallica deposits’"(Project Numbers:10ZA118),and project "Plan of three years of geological prospecting action in Yun Nan province", according to the demand of deep concealed deposits prospecting, the paper start a research of geogas prospecting on great depth lead-zinc ore.The geogas measuring method with the characteristics of deep probing and direct indication of mineralization, good environmental adaptability, simple sampling operation, independent of the covering layer. So this thesis adopts geogas measuring method to detect deep mineralization, study the information of deep mineralization in the exploration area.Aim at control of favorable ore-forming structure and strata in the exploration area, three geogas exploration lines (56#,0#,39#)were depostited. Three measuring lines all throughed the known mining areas and the unknown mainly concerned area, totally completed318geogas measuring points, each measuring point contains geogas information of38kinds of elements. For the convenience, the exploration area is divided into the eastern area known and the western area unknown bounded on the F18 fracture. According to the accumulated value of lead, zinc after normalized, ten anomaly regions of geogas measuring result have been found on the three exploration lines. Based on the former data of geology, geophysics and geochemistry exploration, by the research on the characteristics of geogas anomaly regions, an evaluation work of anomaly regions was carried out, so as to confirme the most avail target region in the field of prospecting to guide the region to further prospecting work.The results of the thesis were summarized as follows:1. By draw the accumulated value of normalized the measuring elements (lead, zinc) profile map, according to the value of Pb+Zn, ten anomaly regions of geogas have been found on the three exploration lines. By comparison, there is a corresponding relationship between the upper part of known ore body and the geogas anomaly, which showed that the geogas measuring method is a effective prospecting method in the exploration area in Dongshan.2. By means of multivariate statistical analysis and combined with other geophysical and geochemical data, basically grasped the geogas anomaly characteristics of the mineralized area in Dongshan.3. A geogas anomaly belt was delineated in section of the Lower Permian Shazipo Formation between the F6and F8fracture on the56#,0#exploration lines, the geogas measuring data were analyzed by cluster analysis, correlation analysis, trace element analysis, The results show that the anomaly belt has the basic characteristics of mineralized geogas anomaly, accompanied with the corresponding induced polarization anomalies, so the anomaly belt should be the most hopeful prospecting targets.4. According to the data of geogas measurement, the possibility of finding the shallow or partly outcropped orebody in the east of Dongshan area is small, so the focal point of exploration is the search for deep buried ore body.5. The preliminary research confirmed that the three methods which are cluster analysis, correlation analysis, and trace element analysis are fit to tesearch geogas anomaly characteristics, established the evaluation standard of geogas anomalies which caused by ore, and then to evaluate geogas anomalies nature is feasible. |
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