Extraction of Mineralized Alteration Information Based on Remote Sensing in Western Tianshan, XinJiang

The wall rock alteration should be reflected in the remote sensing images in the form of spectral information. By the special information they reflected on the spectrum, we can extract the alteration information by using remote sensing image processing methods, in order to get the purpose of finding the mine. Usually, the mineralized alteration in one area is not the result of only one alteration, but the migmatization of various mineralized alteration. Because that the results of band operation and once principal component analysis only enhance and extract single mineralize alteration information, and can't reflect the mixed alteration of various mineralization information. So we could use twice principal component analysis to enhance and extract the mixed information of various mineralization alterations effectively, and show the enhanced mineralized alteration information up clearly. The mixed alterations were extracted by the second principal component analysis method and thresholding technique from Landsat-7 ETM+ remote sensing data in the region of Changgangnuoer. After contrasting with the known ore spot and geologic-structure, we could use the mixed alteration as ore prospecting indicator.