Studying On Extraction Of Remote Sensing Information About Alteration In Eastern Area Of Tibet Garencuo

With the economic growth and the Increasing demand for mineral products , mineral resources will cannot satisfy the needs of future economic development. The geological work is difficult and degree is low in the qinghai-tibet plateau area in China, due to natural conditions, poor transportation and high exploration cost. Now, with the remote sensing technology, electronic technology, and image processing technology development, the application of remote sensing technology in the geological continues to mature. American landsat7 satellite multi-spectral ETM+ image contains a lot of geological information. Geologists can extract wall-rock alteration information from remot sensing image to guide for ore-prospecting work in Tibet.Based on the south t garencuo east area 1:50000 geological mapping project, select the appropriate method enhance wall-rock alteration of the image and extract it. Based on a Comprehensive analysis of wall-rock alteration remote-sensing geological characteristics and geochemical characteristics, provide a potential prospecting area. This study mainly achievements are as follows:1.There are poor traffic and living conditions in Tibet area, , but the satellite remote sensing image quality is fine and suitable for wall-rock alteration information extraction.2.Use methods of principal component and ratio analysis after masking to enhance wall-rock alteration information , and the method is feasible.3. According to the wall rock alterations of remote sensing information intensity, comprehensive consideration of the characteristics and geological characteristics, created 24 iron stain altered remote sensing information area, 34 altered clay,remote sensing information and be divided into A, B and C three levels.4. after a comprehensive analysis of the wall-rock alteration of remote sensing anomaly area, created four sensing ore-hunting prospect areas.Creating sensing ore-hunting prospect areas can reduce work areasand unnecessary work, decrease the mining cost of exploration work in this area, and provide reliable information for further work. Because of the special geographical natural environment of Tibetan areas, wall-rock alteration of remote sensing information extracting in Tibet is extremely important.