| Majiaoshi molybdenum deposit is located in the western polymetallic metallogenic belt of Small Qinling Mountains, Shangluo, Shaanxi province. The exposed strata are from Proterozoic to the Cenozoic. The fold and fracture is developed in the region. Element anomalies such as Mo, Pb, and Zn etc. have been circled by stream sediment survey of 1:50 000 scale, which indicated a polymetallic ore prospect in the area. Before that, although several geological exploration organizations carried out the anomaly investigation and geological prospecting work in the area, but prospecting breakthrough has been unable to obtain for many years because of the use of single survey method.From the year 2011 to 2012, the Sixth Geological Team of Shaanxi Bureau of Geology and Mineral Resources took on the project named “Luo Yuan Polymetallic ore survey in Luonan County, Shaanxi province”, which is covering this area and is a Shaanxi province Fund Project(No.61200901014).The surveyors summed up the past experience and lessons, and synthetically used a variety of exploration means and methods such as large scale geological survey, soil geochemical survey, rock geochemical profile measurement, trenching, drilling engineering verification, etc. Eventually Majiaoshi molybdenum deposit was discovered in the region. Especially the method of 1:10 000 soil geochemical surveys played a crucial role in the process of detecting the deposit.Through the 1:10 000 geological reconnaissances, the ore-forming geological background and geological conditions for mineralization had been generally identified.Soil survey work of 1:10 000 scale in the region has been done. And statistical analysis on the large number of data has been processed. Study on geochemical characteristics of soil in mining area display that the Mo,(Au) are ore-forming elements and Ag, Pb, Zn etc. belong to the indicator elements in this area. In addition, element anomalies such as Mo, Ag, Pb, Zn etc. are reflected again in the region. And abnormal reproducibility is better.A total of 122 single element anomalies had been circled, including 18 Gold anomalies, 25 silver anomalies, 23 Molybdenum anomalies, 18 lead anomalies, 21 zinc anomalies and 17 copper anomalies. And 6 comprehensive anomalies had been delineated, including 3 A-level anomalies.Thereinto, the verification of two soil comprehensive anomaly using geochemical profile of 1:2 000 scale get a molybdenum mineralization belt(Q1).Using surface trenching and sparse drilling engineering to expose and to control the belt, 4 Mo ore bodies had been delineated. Then 333+334 ore resources of 1706.79 tons, Molybdenum resource of 2547.6 tons and associated V2O5 resource of 2548.32 tons had been preliminary estimated.Comprehensive study on geochemical characteristics of 1:10000 scale and geological conditions in this region shows that there is Mo,(Au) deposit prospecting in this area as well. One second-level prospecting target zones and one third-level metallogenic target in the region had been divided; this provided useful clues to the future of the mine prospecting.The discovery of the deposit is a typical example of geochemical prospecting success. Soil measurement of 1:10 000 scales is a feasible and effective method for molybdenum, gold polymetallic deposit in Small Qinling Mountains area. We should vigorously promote the use of this method. |
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