Characteristic Of Primary Halos And Deep Prospecting Prediction Of Yangshan Gold Deposit, Wenxian, Gansu

The Yangshan gold deposit, tectonically located in the triangle area of the north of Yangtze landmass, the south of Qinling orogenic belt and the east of Songpan-Ganzi plot, belongs to the south subzone of Qinling orogenic belt. Yangshan gold depositgive priority tomicro-fine-disseminatedtype, the ore possess the medium and low temperature temperature mineral association and the alteration is characterized by hydrothermal alteration, which is similar to the gold deposits in the west Qinling Mountain.Preliminary consider the deposit genesis type belongs tohypabyssal and medium and low temperaturehydrothermal alteration rock type.Through the methods of mathematical statistics, axial zoning sequence studies,geochemical parameters calculation and establishment of the ideal model of Primary superimposed halo, studied thegeochemical characteristics of primary halo in No.311 ore body’s 3 horizontal passageway systematically and make deep prospecting prediction. The result shows the primary halo prospecting indicator elements are: supra-ore halo indicator elements:As、Sb、Hg;near-ore halo indicator elements:Au、Ag、Cu、Pb;sub-ore halo indicator elements:Bi、Co. The calculation of Primary halo axial zoning sequence of 4 exploration line as follows: NO.01: Sb-As-Au-Bi-Mo-HgCo-Mn-Zn-Cu-Ag-Pb;NO.09:Mn-Co-Mo-Bi-Sb-Au-As-Hg-Zn-Ag-Pb-Cu;NO.17:CuBi-As-Ag-Au-Mn-Zn-Sb-Co-Hg-Mo-Pb;NO.25:Ag-Au-As-Pb-Bi-Sb-Hg-Co-Mn-ZnMo-Cu.The results of correlation analysis show that Au is related with Ag well, meanwhile, Ag is a good indicator element for gold mineralization. Based on cluster analysis, the ore-forming elements and its associated elements of ore body NO.311 can be divided into 3 groups as Au、Hg、Ag、Cu、Pb; As、Sb; Zn、Co、Mn、Mo、Bi. Factor analysis results show that the Yangshan gold deposit had the characteristics of the multi-stage mineralization. The section contour figure of primary halo prospecting indicator elementscontent is well matched with the ore body. The supra-ore elements anomalies, which develop complicated and changeable on the top of horizontal passageway and also have a trend of enhanceat the bottom of the horizontal passageway, have a large scale and intensity.The sub-ore elements anomalies, which have a certain amount of enrichment on the top and at the bottom of the horizontal passageway, have a small scale and intensity, but fluctuate weakly. Geochemical parameters emerge complicated trend of Increases �' Decreases �'Increases�'Decreases�'Increases.Through the establishment of Primaryhalo model and the ideal model of Primary superimposed halo to predict that there may be a low-grade ore body exist in the deep section of exploration line NO.09, and a good mineralization perspective exist in the deepsection of exploration line NO.17.