Remote Sensing Research Of Copper Mineralization Information In Tibet Nimu District

Nimu district is located in the south-central region of the gangdese metallogenicbelt which is located in Tibet. At present in the area has been found several mines,such as Bairong、Gangjiang、Chongjiang、Tinggong etc. In its periphery also foundseveral potential ore bodies and abnormal. So in the area is expected to form a largeeven very large porphyry copper clusters. But the area is located in the mountains, athigh altitudes, cold climate, traffic inconvenience etc. These are to conventional fieldgeological prospecting work to increase the difficulty. So it is very necessary toresearch the copper mineralization information of the area by the remote sensing tools.In this paper, we first do the work in research area of the wall-rock alterationinformation extraction and linear and ring structure interpretation. Then combine thebasal geological information and the geophysical information, overlay andcomprehensive analysis these information. At last we delineate Remote sensingore-hunting prospect areas and to analyze them.(1) The article studies the wall-rock alteration anomaly information extraction inthe area based on the ASTER data. The area covers three original images. ThenCrossTalk correction, radiation calibration and FLAASH atmosphere correction willbe done on the images, inlay and cut them to get the image of the research area.（2）In order to extract the accurate altered information，it need to eliminate theinformation which will influence the results of the image extracted. After observingand analyzing, five kinds of the information are confirmed to eliminate：the water、thequaternary、the shadow、 the vegetation and the ice and snow. According to thetypical porphyry copper mining hydrothermal alteration zoning pattern and the actualsituation of the area, it confirmed to extract the following four kinds of the alteredinformation: the iron ion altered mineral、The alumina hydroxyl altered mineral、the magnesium hydroxyl altered mineral and the carbonated root ion altered mineral.The extraction method is main component analysis method. According to the normaltheory and error theory, we do the standardized classification of the strength grade,dividing the extraction altered abnorma into three levels（3）Using ETM+remote sensing image in the study area for remote sensinggeology interpretation work，linear structure and ring structure are the main structureto interpretative. Then we do the work of the orientation analysis and the densityanalysis for the extraction of the results, Analysis of the line and ring structure forbearing and distribution clusters. And the key analysis is the mineralization favorableposition of the intersection and the tangent point of the line and ring structure.(4) Adding the altered information and geological information together, analysisthe relationship between the altered information and the stratigraphic and the lithology.From the angle of geophysical to analysis the metallogenic information of the studyarea by the ground△T magnetic anomaly plane equivalence value map of Gangjiangarea which get by collection.(5) We do a comprehensive analysis of the remote sensing altered information、the line and ring structure information、the basic geological information and theGeophysical information. Confine six place of the remote sensing mineralizationvision area in the study area in the end. providing important remote sensinginformation for the prospecting work in this area.