基于ASTER的雅鲁藏布江缝合带泽当-罗布莎蛇绿岩套分析和组分识别

Lithological mapping of ophiolite composition in Zedan-Luobusha,Yarlung Zangbo suture zone using Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER) data.

本文通过对西藏雅鲁藏布江缝合带泽当-罗布莎地区蛇绿岩套的主要岩石组成和蚀变矿物的标准波谱吸收特征分析,比较了标准光谱库的相应岩性光谱吸收特征和ASTER数据波段特征之间的关系,采用连续统去除、比值法和光谱角制图法对ASTER影像数据进行处理及相关岩性和矿物提取。结果表明,蛇绿岩组分岩性中亚铁离子和Fe-OH,Mg-OH的可见-短波红外吸收特征显著,而且有一个宽波长范围的Si-O热红外光谱特征,基于这些光谱特征采用ASTER数据和比值法与光谱角制图法可有效地识别蛇绿岩的主要岩性和相关矿物成分及其空间分布,结果与地质资料基本吻合。

Based on the absorption feature analysis of rock composition and altered mineral of ophiolite in Zedan-Luobusha,Yarlung Zangbo suture zone,Tibet and the spectral comparison between ASTER data and existing spectral library,the detection of the rock types and related minerals was accomplished using ASTER data with the Continuum Removed,Ratio Image and Spectral Angle Mapper methods,taking the spectral curves from existing spectral library as the reference spectra.The results show that the VNIR-SWIR absorption features of ferrous-iron and Fe-OH,Mg-OH are dominant and there is a wide wavelength range of Si-O TIR spectral features in the basic-ultrabasic ophiolite composition rock spectra.And the results also show that the use of ASTER emission and reflectance data as well as the mapping methods can effectively detect the main rocks and related minerals of the ophiolite complex and their spatial distribution,which are almost coincident with geological map in existence.