Application Of WorldView-2 Prospecting In GeJiu Polymetallic District,Yunnan Province

With the development of remote sensing technology and the demands of large scale remote sensing geological survey,the traditional remote sensing geological research which based on medium-low spatial resolution images(such as Aster,ETM+,etc.)has been difficult to meet the require of current fine remote sensing prospecting application.As a new remote sensing data source,WorldView-2 image has unique advantages in terms of spatial resolution,spectral resolution and radiometric resolution.These make it has a very important role in the remote sensing prospecting research,such as the interpretation of fine ore controlling factors and so on.Based on the analysis of regional metallogenetic geological background in the Eastern Gejiu tin-copper polymetallic ore cluster area,this paper will make use of WorldView-2 images to conduct a series of remote sensing prospecting studies.The research results have certain reference value for the exploration of the periphery of this ore-concentrated area.Main achievements of this study are as follows:(1)Study on the formation enhancement methods of the research area: On the basis of comprehensive analyzing characteristics of WorldView-2 images and spectral curves of different lithologies,the author carried out a series of formation enhancement methods,which included spectral enhancement methods and spatial domain methods.At last,the "contrast transformation + HSV transformation +principal component transformation + high pass filtering" method was adopted,and good interpretation effects had been achieved.(2)Interpretation of linear and circular structures: Based on the widely used symbols of linear and circular structures,the research area's symbols were established through the "principal component transformation + high pass filtering" method,which could boost up WorldView-2 images' edge and texture information.According to the established symbols,linear and circular structures of the study area were extracted,and satisfactory results were obtained.(3)Extraction of the ferric contamination anomaly: On the basis of analyzing measured iron oxides' spectral characteristics,the author adopted principal component analysis and "C-A" multifractal approach to extract FCA in the study area.In the double logarithmic scatter plot of the "Pixel DN-Area" model,the alteration anomaly and the background of the iron stain were corresponding to different lines.By finding the boundary point between the two straight lines,we can avoid the phenomenon of leakages in the traditional alteration extraction method,meanwhile,enhance the weak alteration information in the complex environment effectively.Furtherly,the result was divided into three levels under the multifractal method.(4)Synthetical information metallogenic prognosis: In this aspect,the author utilized the MORPAS software to integrate all favorable information for prospecting,including the interpretation results of remote sensing and geochemical prospecting information,and took advantage of the weight of evidence metallogenic prediction model to delineate three favorable metallogenetic zones.