Research On The Extraction Methods Of Geochemical Anomaly Of Soil

The object of geochemical exploration is to discover geochemical(primary and secondary)halo by systematically measuring the geochemical properties of natural materials.It is an efficient,intuitive and effective method for mineral exploration.The determination of lower limit anomaly is the core in geochemical exploration,and it is also a key link to determine the success of mineral exploration.In this paper,we collect data of geochemical processing methods,geological,and geochemical exploration from Jiamulong Au deposit in Xiahe Country of Gansu Province.The 1:10 000 soil geochemical data ini the study area were analyzed by correlation analysis,cluster analysis and factor analysis,to identify the element combination and the zoning patterns as follow:(Cu-Pb-Zn-Ag)-(Mo-W)-Bi-(Au-Sb-As).According to mean standard deviation method,cumulative frequency method,median contrast filtering method in sub-area and trend surface analysis method,the anomaly lower limits of 10 elements are obtained.The application effects of four geochemical data processing methods in this area are compared and analyzed.Combined with the metallogenic geological background,the anomalies are comprehensively analyzed and evaluated,and four comprehensive anomalies with prospecting potential are delineated.Based on the research,the conclusions are as followed:1.The lower limit of fixed-value anomaly highlights the high-background part of data and is suitable for small-scale geochemical anomaly identification.The lower limit of variable-value anomaly conforms to the changing trend of geochemical surface.In the process of delineating anomaly,the high-background anomaly is high and the low-background anomaly is low,which not only strengthens some weak anomalies,but also weakens some anomalies in high-background area,which is the advantage of the lower limit of variable-value anomaly.It is suitable for large-scale regional anomaly recognition with complex geological background.2.Although the cumulative frequency method has no requirement for data distribution,it is only suitable for data distribution which is more uniform and does not have a number of centralized extremes(less than 15%).The advantage is simple to calculate and easy to implement.3.Based on the metallogenic geological background and tectonic environment of Jiamulonggou gold deposit,the advantages and disadvantages of four geochemical exploration methods are analyzed.Based on the small area of the study area(16 km~2),we conclude that the mean standard deviation method is the most suitable geochemical exploration method in this area.4.The direct geochemical indicator for prospecting in this area is the Au-Sb-As element assemblage,and the regional prospecting indicators are the NW-trending faults and their secondary faults.