Remote Sensing Alteration Extraction In Dexing Porphyry Copper Deposits Area Of Jiangxi Province

On the basis of geological remote sensing alteration information and structural information for remote sensing prospecting,and taking Jiangxi Dexing porphyry Cu polymetallic ore district as the study area,and using DEM and Landsat OLI as the basic data,the structural information or alteration information had been extracted and analysised.Compared to the traditional methods in the alteration information extraction of remote sensing,the theory of fractal method has some advantages,then provides more comprehensive information for the regional ore prospecting.The main researches and achievements are as follows:(1)Analysis of the characteristics of the structural information in the study area,this paper chooses DEM and Landsat OLI as the data source,and this data carries on the pretreatment.The linear structures extract with DEM data have use computer automatic,and combined with the selection of OLI 753 synthetic image as the visual interpretation map,and the further analysis of the structure information extraction for regional prospecting.(2)Analysised the spectrum characteristics of alteration information,according to the alteration types of the Dexing copper polymetallic ore concentration area,alteration mineral analysis will be divided into the iron factor,silicide factor,argillation factor of the ratio method and the containing hydroxyl or iron minerals alteration factors of principal component method,then extracted the five alteration information respectively,and the five alteration factors conduct the twice principal components analysis to extract the mixed alteration information.(3)In this paper,the results of remote sensing alteration information extraction based on threshold method and fractal theory respectively are compared and analyzed.Another,Using cluster analysis method to eliminate some false anomaly information of the mixed alteration information extraction,and finally get the results of mixed alteration information in the study area.(4)According to the existing geological and mineral information,the analysis and verification of the extracted structure information and alteration information in the study area,and the further spatial analysis of remote sensing prospecting information,finally get the structural,and alteration information in Dexing area,and which are closely linked with the distribution of the lithology and ore deposits.Therefore,the development degree of the structure and the abnormal information of the surrounding rock alteration are still the important research contents of the metallogenic prognosis.The results showed that the remote sensing alteration and the structural information as a geological record,and the alteration information not only has the characteristic with multiple fractal characteristics and the fractal characteristics,compared with other traditional methods,such as threshold method,the fractal method can carry on the reasonable classification of remote sensing alteration anomaly effectively,to make up the shortage of the traditional method of threshold method,and achieved good results.Therefore,the fractal method provides the new method of a quantitative technique and the selected threshold accurately in the study of the alteration information for geologists.