Research On Remote Sensing Mineralization And Alteration Information Extraction In Mingyue Mountain Area Of Jiangxi

The tectonic position of Mingyueshan area in Jiangxi Province is located in the structural contact zone between Yangtze block and Cathaysian Block.The unique geological and structural conditions shape the unique metallogenic environment in the study area,which has good prospecting potential.However,it is very difficult to use traditional geological means to carry out prospecting work,and the combination of remote sensing technology and prospecting work can effectively solve the problems of difficult and slow extraction of alteration information.According to the characteristics of high vegetation coverage in the study area,this paper takes ETM + image as the data source,comprehensively uses standard principal component analysis,eigenvector principal component analysis,directional principal component analysis and secondary principal component analysis,etc.on the basis of weakening vegetation interference,through the distribution characteristics of remote sensing mineralization alteration anomaly information,It provides strong support for the delineation of metallogenic prospect areas in the study area.The main research results are as follows:(1)ENVI software is used to carry out atmospheric correction,terrain correction,geometric correction,image fusion and other preprocessing steps for ETM + images in the study area,which optimizes the information loss caused by error factors,greatly restores the real situation of complex surface,strengthens the difference information characteristics of different surface features,and provides a good guarantee for the accuracy of subsequent alteration information extraction results.According to the terrain characteristics of the study area,terrain correction steps are added to improve the interference of terrain shadow.(2)In this paper,four principal component analysis methods are used to extract alteration information.Among them,the secondary principal component analysis method and standard principal component analysis method are successful in extracting iron alteration information,the eigenvector principal component analysis method is effective in extracting argillaceous alteration information,while the directional principal component analysis method is ineffective in extracting alteration information.The results of the four methods are compared,and the second principal component analysis method is the best.(3)In the color composite map obtained by standard principal component analysis,eigenvector principal component analysis and secondary principal component analysis,it is found that argillization alteration information and Ferritization alteration information are mainly distributed in the eastern and central regions of the study area,and are densely distributed in a porphyritic manner,while other parts are not exposed in a large area.The distribution range of alteration information obtained by principal component analysis is generally consistent with the distribution of proven ore spots.(4)Based on the spatial superposition of the extracted mineralization alteration information and the existing geological data,three metallogenic prospect areas are divided in the study area,one for grade I,one for grade II and one for grade III,and the metallogenic prediction map is made.