Study Of Remoted-sensing Information Extraction Of Alteration In Sunitezuoqi, Inner Mongolia

Wallrock alteration is an important indication for exploitation,it is mean that the componential,ructural and tectonic change of the rock result from the temperature,hydrothermal and fizzwater hydrothermal. Frequently,the ferriferous metallic mineral and alteration mineral which have OH– or CO3 2- Because of hydrothermal ore-forming solution,Most of endogenetic deposit have pyrite mineralization,sericitization,carbonatation etc alteration phenomena, moreover, the region of alteration is bigger than deposit,this provide conditions for information extraction of alteration.Most of altered rocks have major Fe3 +,OH-,CO3 2-.A a mass of rocky spectrum test data prove that ,from visible region to NIR,these ion have reflect or absorb key band,but the chemical constituent of rock-forming mineral(Si,Al,Mg,O) don't have above-mentioned spectral diagnostics,this is the physical foundation of information extraction of alteration. Alteration information not only have spectral characteristics but alse spatial character, The spatial characteristics of alteration information means that,from geologic function aspect,the spatial distribution of alteration information be dictated by structure,rock mass as well as other metallogenesis. The spatial characteristics of alteration information is explained on the basis of the geologic interpretation of alteration information.The geotectonics of Sunitezuoqi region locate on north of giantepicontinental collision orogens,Mesoproterozoic Era,in North China, the joint banding between north China plate and Mongolia plate.The main mineralize stratum is the group of Dshizhai and Zhesi of Permian.The ore control structure is near transmeridional,east northeast,west northwest sub linear structure,circular structure and large-scale ductile shear zone of the reseasch area. The monzonitic granite of Yanshanian and indo-chinese epoch,the granodiorite of terminal Variscan are closely related to metallogenesis. The main alteration type of the reseasch area are silicify,sericitization,chloritization,kaolinization,carbonatation,limonite,iron pyrites,galenite,chalcopyrite etc.Use Ratio compute,Principal Component Analysis(PCA),Spectral Angle Mapper(SAM) etc to extract the alteration information according to the result of the extraction of alteration information,the feature of linear structure and circular structure also areal geology datum.The aim which is using various method of information extraction is that the alteration information can validate themselves one another and improve the distributed dependability of the alteration information. The result of alteration information Extraction indicate that the ferreous alteration and argillization alteration consist in the north and middle part of the reseach area also northeast distributing. Argillization alteration is intense and ferreous alteration is faintish. The distributing of alteration information be dictated by sub structure and relate to the rock mass of Yanshanian,indo-chinese epoch and terminal Variscan. Silicated alteration consist in the middle part of the reseach area, which is related to the dike of the middle part.According to the result of alteration information extraction,thecharacteristic of linear programming and circular structure,the distributional characteristics of rock mass etc compositive remote-sensed information, establish three remote-sensed metallogenic prediction units, which consist in the north,middle part,southwest of the reseach area. Excavate the metallogenetic condition and metallogenetic characteristic of the prognostic units adequately, provide technical base for mineral resources investigation of the reseach area.