The Application Of Short Wavelength Infrared Technology In Mineral Mapping And Remote Sensing Lithology Identification

Hyperspectral Short Wavelength Infrared (SWIR) technology is one kind remote sensing technique applying to the spectrum mineral measures. In short wavelength infrared, hydrous mineral, hydroxyl mineral (most are layered silicate and clay-genus), sulphate and carbonate have specificity, which made short wavelength infrared technology has broad applying prospect in mineral mapping. At present it is mainly used to altered mineral mapping. Two study areas are chosen: Ma An Shan copper and molybdenum deposit in Tu Quan County of Inner Mongolia and Quanzhou area in Guilin of Guangxi . In Ma An Shan deposit SWIR is used to rock and mineral spectral measurement. By means of process and analysis of spectral data, the spectral signature of typical altered mineral is studied, the distribution characteristics and regularities of altered mineral are analyzed, the practical and operational information is provided to the geological exploration for this area. In Quanzhou area by means of spectral measurement of lithology and stratum in typical district, comparison and analysis of image spectrum, the identification and extraction method of remote sensing lithology information is studied.Main study achievements as follows:(1) The principle of short wave infrared technique, short wave infrared sorption specificity of altered mineral, spectrum effect, combination spectrum and the influencing factors for rock or mineral spectrum had been studied sufficiently. These are bases for altered mineral mapping and lithology distinguishes extracting experiments.(2) Research the relation between spectral reflectivity, characteristic absorption strength of altered rock and alteration intensity. The same kind of altered rocks have the similar waveform and the characteristic absorption band is consistent. But the spectral reflectivity and characteristic absorption strength is not consistent and varied with different alteration level.(3) Study the relation between mineral and mineral, mineral and metal, mineral and structure, and the mineral distribution feature and regularity. In the study area of Inner Mongolia, the correlation between montmorillonite, kaopaque and calcite is fairly high. In the geological sketch map and profile curve diagram, argillation alteration mainly composed with montmorillonite and kaopaque have obvious zonation. The curve peak value of montmorillonite, kaopaque and calcite all appeared on the fault tectonic zone and mineralization alteration zone and nearby regions. Illite is found on the peripheral region. It can be concluded that argillation alteration have the close origin relation with the fault fracture zone and metal mineralization.(4) In Guilin area, by the comparison and analysis of actual spectrum measured by near infrared mineral analyzer and remote sensing image spectrum, band ratio, spectral mapping and mixed pixel decomposition are used to identify and extract lithology information. Dolomitite and limestone can be fairly separated from carbonate rock. The purpose of this study is reached on the whole.