| Studying area is Mozhugongka region, which is located in the south-central of the Tibet and includs the two known deposits——Qulong porphyry copper deposit and Jiama copper-polymetallic deposit. Studying area is a alpine areas of deep cuts, high elevation and steep slope, so it is more difficult for large areas of prospecting work. From this perspective, it is essential to study the remote sensing ore-finding information of the known areas using remote sensing means, thereby further grasping the prospecting information from the macroscopic and providing effective aids for other prospecting method. Based on the remote sensing prospecting alteration and interpreted of linear structure and ring structure information extracted from the studying areas and combining lithology, geochemical and geophysical prospecting data from a comprehensive analysis of information, the method, which gives priority to prospecting information based on remote sensing and is supplemented by other information, proved to be important and effective.ETM+ image and ASTER images were used as remote sensing data sources. Firstly, with previous research results, researches on the prospecting alteration information extraction theory and analysis of the spectral characteristics of ETM+ and ASTER data were done; secondly, preprocess the images and remove the interferences; finally, extract the remote sensing prospecting alteration information by using the ratio method or the principal component analysis. Using spatial overlay analysis for the result of alteration information from different data sources extracted, quantitative analysis of space superposition alteration information, then the comprehensive altered anomaly information was got based on different data sources and method of alteration information extraction.With the spectral band characteristics of ETM+ image, by doing relevant analysis of band, to get ETM7\ETM4\ETM1 band to RGB combination, then uses this image to do visual interpretation of geological structure. Remote sensing signs of structural interpretation in the studying area are established, and interpreted linear structure and ring structure, and obtained the geological structure interpretation graph, then orientation analysis of linear structure, density analysis of linear structure and ring structure. Linear structure and ring structure are not the independent geological structure phenomenon, they appeared with different combination forms, so, Through analysis the linear structure concentration area, the ring structure concentration area, and the linear-ring structure concentration area, thus determine the favorable ore-prospecting area, finally, to verify remote sensing linear-ring structures has a certain internal relations with the mineral in the studying area.The results, made by compositely overlaying the remote sensing alteration information extracted from the studying areas with the formation lithology, geochemical and geophysical information, showed a good positive correlation, so the remote sensing alteration information extracted in this paper proved to be reliable and efficient. At last, An comprehensive analysis of prospecting information for Qulong and Jiama mining area was made and the results showed that: In the mining areas, remote sensing alteration information, linear-ring structure and formation lithology, geochemical data prospecting information appeared to be highly positive-correlated, which verified the validity of the remote sensing alteration information and linear-ring geological structure as prospecting information.In order to locate the prospecting areas more accurately, the emphasis is that: improving the remote sensing anomaly extraction methods and processes with RS and GIS, strengthening the interpretation of the extent of remote sensing geological structure to further improve the efficiency of remote sensing alteration information and linear-ring structure in prospecting work and thereby comprehensively analyzing the multivariate prospecting information. |
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