Study On Extraction Method Of Alteration Information Of Porphyry Copper Deposit In Middle And High Vegetation Coverage Area

The study area is located in the Gezan of Shangrila area,which belongs to the Hengduan Mountains,south-eastern TibetanPlateau.The region has ragged topography,thick vegetation,ice and snow coverage.The elevation of region is 3000-4000 m.Because of cold climate,economic backwardness,poor transportation condition,poor field work condition,it is difficult to implementregular mineral resources exploration.Remote sensing image has broad horizon,can be a macro to reflect the relationship between the various geological phenomena,in the interpretation of the regional geological information have irreplaceable advantage.This paper chose two regions as typical research area: Pulang and Baoxingchang mining area.This paper presents an alteration extraction method based on the combination of mixed pixel decomposition and independent component analysis(ICA),which is based on the ASTER data for the study of remote sensing alteration information extraction in the high vegetation coverage area and the Xuejiaping study area.In this paper,ASTER data are used to extract the mineralization alteration information of the Pulang mining area and the Xuejiaping mining area.The information of potassium,sericite and green rock is extracted.In this paper,the data preprocessing of remote sensing images is carried out,and the interference removal of image interference is eliminated.The traditional high-end cutting mask interference removal and the quantitative elimination of interference information based on linear mixed pixel decomposition are adopted.The principal component analysis method and independent component analysis were used to extract the mineralization alteration information of the porphyry type copper deposit in the vegetation coverage area,and the extraction results were superimposed with the geological map of the mining area.The advantages and disadvantages of each method are compared and analyzed.It is found that independent component analysis and principal component analysis have advantages in extracting different alteration information.When the remote sensing alteration information of the porphyry copper deposit is extracted from the medium and high vegetation area,the pseudo-alteration information extracted by the linear mixed pixel decomposition to the interference information is reduced compared with the conventional mask method.On the basis of this,the ICA method is more accurate than PCA in extraction of kaolinite and sericite,and PCA is more accurate than ICA in extracting potassium information.The ICA and PCA methods can be combined on the basis of linear mixed pixel decomposition and interference information,and the extraction accuracy of remote sensing and alteration information can be improved by extracting the alteration information of porphyry copper type in medium and high vegetation coverage area.It also shows that the independent component analysis method based on linear mixed pixel decomposition is feasible to extract the alteration information of porphyry copper deposits in medium and high vegetation coverage area.The remote sensing,GIS and geological comprehensive analysis techniques are used to improve the remote sensing and alteration information of medium and high vegetation coverage area,and the accuracy of mineralization alteration information extraction is improved,provide a basis for mineralization prediction,and more efficient for mineral exploration.