| Chifeng-Weichang area is located in the conjunct region between two tectonic units of North China Craton and Inner Mongolia-Daxing'anling Geosyncline belt, whose regional geological background is complex, with frequent magmatic activity as well as distinct metamorphism and deformation. There are many researches on the geology, geochemistry, geophysics, metallization, ore deposit and metallogenic belts in the research area. As a result, many ore deposits, especially for gold deposits, have been founded around Chifeng in the east and very few deposits recognized around Chifeng in the west even though the geological background is quite same in the whole area. So the study focus metalloginic difference between Chifeng and Weichang area, collecting and processing the data of geological, geochemical, minerals investigation and exploration through the modern ore-forming theory. Based on the comprehensively study, the forecast of gold prospecting has been conducted and then discussed the metallogenic differences on gold ore potential between Chifeng area and Weichang area, which is providing new ideas for the gold exploration.The geological study has proved that the Archaean strata, especially the one near the intrusion with interlayer of hornblende-plagioclase gneiss, is close related to the Au-forming. Granitic intrusion has played an important role and fault has served as a conduct and depositing site during the ore forming.This thesis has collected, processed and dealt with the geochemical data and, combining with regional geology, mineral resources data, set up a spatial database of geology, geochemical information of the study area by GIS software of MapGIS. Total 11 Au-forming related elements of Au, Ag, As, Sb, Hg, Bi, Cu, Pb, Zn, W, Sn, Mo are selected and series of geochemical contour maps and the equivalent zones maps are formed with the help of GeoExpl software, showing the anomalies related with gold. The anomalies can be divided into outer zone, middle zone and inner zone at scale of 85%, 95.5% and 98% frequency values. Fixed the background content, the geochemical anomalies have been mapped and described for the element distribution and concentration. It was summarized that element Au occurs in a complicated way in the south and gentle in the north, element Ag distributes as two N-E extending belts, while As is gradually decreasing from north to south and Sb anomaly extends in the same direction as local structure. Based on the single-element geochemical anomalies, combined anomaly maps of elements have been compiled and the characteristics of the combined anomalies have been analyzed, which provide strong geochemical evidences to the mineralization forecast.Based on analysis of ore-forming geological setting, gold mineralization, and metallogenic feature, the paper considered that the Archaean strata, faults, acidic and mediate intrusions were the main ore-controlling factors. According to the detail description of typical gold ore deposit, the relation between Au mineralization, Au geochemistry anomalies and geochemical association are analyzed respectively to establish regional geological and geochemical metallogenic predicting model.According to the metallogenic prediction criteria and indicator, 7 different levels of predicting area are delineated for the predicting element or element combination and deposit types. And gold potential resources of specific predicting area are calculated by the methods of metal content in plane and resources fitting linear with typical deposits known. It is studied the Au mineralization differences between the east and the west in the area. The research has confirmed that the area is very potential for gold exploration not only in the east but also in the west.
|
PDF Full Text Request