The Recognizing And Comprehensive Evaluation Of Geochemical Anomalies In LuBei Area, Inner Mongolia

Geochemical information is a kind of tiny mineralized outcrop, which could provid direct information of mineral exploration and improve prospect efficiency. The research area is located in the middle and south sections of Da Hinggan Mountains, in which have found many geochemical anomalies of copper-polymetal deposits. How to scientifically and reasonablely select and appraise these anomalies, is key to the effect of mineral exploration.This paper analyzes the 1:50000 stream sediment data in the LuBei area, Inner Mongolia,by use of traditional statistical methods and the concentration-area muti-fractal method, and determines the anomalous threshold of regional geochemical data. The results show three points as follows. Firstly, most values of the anomalous threshold calculated by traditional statistical methods is less than that by muti-fractal method. Secondly, the distribution characteristics of geochemical fields is not followed by the normal distribution and lognormal distribution, but express the characteristics of high cluster fractal distribution. Thirdly, According to the comparison of overlapping the geochemical anomalies map of Cu and Ag element by two methods and the mineral deposits map, the quantities of anomalies confirmed by fractal methods which have relation with the copper-polymetal deposits are less than that by traditional statistical methods.The traditional mathematics geology, such as cluster analysis, principal factor analysis, was effectively applied to study the assemblage of 12 elements in the area of geochemical anomalies, and the principal factor score anomalies were used by characterizing association anomalies of main metallogenetic elements. The studied results show as follows. (1) According to the varimax rotation, Factor 1 account for 23.17 percent of the variance contribution,the area of high scores of F1[Cu-Co-Ag] is coincided with the mineralized point. Cu,Co and Ag which are all chalcophylic element represents the association of mineralized element. (2) F2[As-Mo-Sn-W] which represents the association of high temperature element is not coincided with the mineralized point. (3) F3[Pb-Zn] which represents the association of medium temperature element is coincided with the mineralized point. (4) F4[Cr-Ni-Au] is not coincided with the mineralized point. (5) The result of cluster analysis is consistent with factor analysis, those elements are taken apart into 4 clusters while the correlation coefficient is 0.4, one of the clusters is the association of Cu, Co, Ag, Pb and Zn.By using induced polarization method in the oresearch promsing area of HuoRiGenDaBa west, confirms 9 IP anomalies. The polarization ratio of the rock in the earth's surface are all lower indicates that the high IP anomalies due to the mineralized substance under the surface. The mineralization have close relationship with granodiorites which assumes veinlet and disseminated copper mineralization. The mineralization differ from quartz vein and hydrothermal vein but turn out the potentiality to discover porphyry copper deposits.