Geochemical Anomaly Identification And Mineralization Prediction Of Deep Soil In Shallow Coverage Area

At present,the possibility of discovering new deposits in exposed areas has become increasingly small.People face two major ore-prospecting challenges,one is the exploration of indiscernible ore deposits,and the other is finding ore in coverage areas.With the help of the analysis technique,the characteristics of geochemical exploration are distinguishing the mineralized abnormal information effectively that are invisible by the naked eye.However,the burial depth of the ore bodies in the covered area,the influence of the surficial geochemistry and human activities are the reasons for the hidden and weak geochemical anomalies.Therefore,it is more important to explore the new theory and method of geochemical prospecting in the shallow coverage area.Zhangbaling-Guandian area is located in the northern part of Zhangbaling tectonic belt,eastern part of Anhui Province,on the one hand,it has strong tectonic and magmatic activities and closely related to the Jiaodong gold deposit area in China,on the other hand,it is a potential gold prospecting area.The study area belongs to low mountains and hilly landscape with shallow outcrop.The average thickness of soil cover is about 1.5 meters.In this paper,it focuses on the 1: 50 000 scales of deep soil geochemical data of Au element in the eastern part of Anhui province-the area of Zhangbaling-Guandian.Then it extracts geochemical anomaly of Au,As,Bi,Pb,Sb,Sn six elements with singularity mapping technique,based on multrifractal theory and it has delineated 6 prospecting targets for exploration.The results show:(1)Through the statistical analysis of characteristic parameters and element symbiosis combination in geochemical data,it has found that Au elements have high range and very high coefficient of variation,and the spatial distribution of elements is not balanced.The results indicate that there is a good potential of gold mineralization in this area.The multivariate statistical analysis suggests that there are similar data characteristics of As,Bi,Pb,Sb,Sn in the region,while the target element Au is shown to be independent of a single class.The area of Au mineralization should be studied with Au as a main indicator element,As,Bi,Pb,Sb,Sn as secondary indicator elements and then carry out further mineral anomaly identification.(2)The distribution characteristics of Au singularity index in deep soil have a good correspondence with the distribution of known Au-polymetallic ore spot in this area,and it also reflects the spatial relationship between deep concealed fracture structure and known ore deposit.The singularity mapping technique which is based on non-linear theory can lower the impact of geochemical background and has tremendous advantage in identify geochemical anomalies compare with traditional method,it can be applied in the study of geochemical anomaly identification under the hidden and shallow environment.(3)By analyzing the vertical distribution characteristics of different elements in soil profile,it is shown that from the surface to the deep,the variation of geochemical elements content is very random and the regularity is poor.Thus,the adoption of topsoil in the region to characterize the original distribution of deep earth chemical elements may have significant inaccuracies and uncertainties.(4)Based on the singularity index of geo-chemical elements,using the 85% cumulative frequency method to determine the anomaly threshold of single element anomalies.This paper selected 34 integrated anomalies among which are 10 type A(4 type A1,6 type A2),12 type B(5 type B1,4 type B2,3 type B3)and 12 type C(6 type C1,4 type C2,2 type C3)integrated anomalies.On the basis of this,According to the metallogenic geological features,ore-controlling conditions,metallogenic regularity,mine(mineralization)sites and the distribution of geophysical and geochemical abnormalities,it predicts the study area of metallogenic prospect and preliminary delineation 6 metallogenic prospect areas.Besides,it analyzes ore prospect and lays a good foundation for the geochemical prospecting work in this area.