辽宁兴城地区岩石光谱测试及特征分析

Rock Spectral Measurements and Their Characterization Analysis in Xingcheng Area,Liaoning Province

在辽宁兴城野外实习基地采用ASD光谱仪完成不同岩石样品光谱测试的基础上,分析了不同类型、不同地质时代的岩浆岩和沉积岩,及其风化面和新鲜面的光谱曲线特征。兴城野外不同岩浆岩与沉积岩光谱曲线形态相似,新鲜面和风化面的特征光谱吸收位置相差不大,但新鲜面的反射率普遍高于风化面的反射率;岩浆岩和沉积岩样品一般在波长为900nm左右存在铁离子吸收谷;除了在1 400nm和1 900nm处有水汽吸收带外,岩浆岩和沉积岩样品在2 200nm左右还存在强吸收谷,而灰岩在2 300nm左右有比较高的吸收谷,这也是利用实测光谱进行岩性分类的理论基础。但是,不同地质年代下的岩石光谱曲线变化并无规律,更多地与岩石结构、成分和环境因素等相关。这样,岩石光谱测试及其特征分析可满足研究区岩性识别、矿化蚀变信息提取的需要。

Remote sensing images record the rock spectral radiation characteristics and morphological characteristics.In the study,after the spectra of different rocks were measured in Xingcheng area for ASD spectrometer,the spectral characteristics are analyzed to the rocks with fresh and weathering surfaces for different rock types and different geological era.The spectral curves of different sedimentary and magmatic rocks are similar,and their absorbing positions have the same wavelength.But the reflectance of the fresh surface of rocks is higher than the weathering surface.Around 900 nm,the spectral absorption valley may be due to iron ions.In addition to 1 400 nm and 1900 nm of water vapor absorption band,sedimentary and magmatic rocks have a strong absorption valley around 2 200 nm,while limestone has a relatively high peak around 2 300 nm.These are theoretical basis of rock classification in the spectral method.But the spectral features of rocks on different geological era are not obvious.And it is related to the texture and components of rocks. Thus,the rock spectralmeasurements and spectral characterization analysis can meet the need of lithology recognition,mineralization alteration information extraction for geological investigation and mineral exploration.