Remote Sensing Alteration Information Extraction And Prediction In Zhegu Area Of Tibet

Zhegu is located in the mountain area of southern Tibet plateau, in which geological exploration is inadequate because of the influence of altitude conditions, but the development potential of Mineral resources is tremendous. The area is sparsely populated with a low rate of vegetation; all kind of rocks are exposed to the surface which is a great advantage for using remote sensing technology to extract minerals information and forecast mineral resource.This paper uses the ETM+and ASTER data to extract the Geological and mineralization information of Zhegu area of Tibet, Main achievements have been gained as follows:(1) False color image which is combined from optimal bands of ETM+is used to interpret geological information of Zhegu area in Tibet.Types of the rocks, characteristics of lithological association in the stratum and the characteristics of the line-loop structure are studied in the area.(2) Spectrum features of the altered mineral which are composed of Fe3+, OH-and CO32-groups are analyzed to find out the relationship between the altered minerals’spectrum and bands of ETM+and ASTER remote sensing data which provide a theoretical basis for the remote sensing alteration information extraction.(3) Ratio and principal component analysis methods are adopted to extract iron alteration, clay alteration and silicified alteration information in the workspace after masked the snow and water on the plateau. The abnormal thresholds are determined by means of mean+skewness*standard deviation, the alteration information is compared with the artwork through PCI8.2algorithms library.(4) Characteristics of ETM+and ASTER data’s extraction of geological information in Zhegu are analyzed and the results of the mineralization and alteration information are Compared.From which we find that the ASTER data has a greater advantage in the extraction of OH-、CO32-groups.(5) Based on the remote sensing alteration information extraction results, geological exploration results and classification principles of Prediction,7 mineralization prediction areas are specified, in which contains2potential areas of class A,3potential areas of class B, and2potential areas of class C.