干旱区TM图像岩石地层信息提取与分析方法研究

Extraction and Analysis of Lithostratigraphic Information from Landsat Thematic Mapper Imagery in Arid Region

本文以新疆柯坪地区为例，通过不同岩石地层单元的岩石化学特征，矿物组合特征和室内反射光谱特征研究，结合图像数据的计算机处理结果，对干旱区沉积岩的ＴＭ图像岩石地层信息提取方法进行了探讨。经对岩石测试分析数据和其图像表征的综合分析，作者将区内的岩石地层单元划分为１０类，划分精度可达到岩性段，说明了ＴＭ图像在岩石学应用研究领域具有较大的潜力。研究中采用的技术方法也具有一定的推广性。

The study focuses on the Kalpin Region, where is of an arid climate, 40-80mm annual precipitation,sparse vegetation, and well exposed rocks. The strata of the study area are mainly composed of carbonates from littoral to shallow marine factes and elastics from marine-continent transitional to terrestrial factes.Based on the synthetical analysis of the characteristics of chemical and mineral composition, renectance specturm, and imagery brightness values of different rocks, the method for extracting the lithostratigraphic information from Landsat Thematic Mapper (TM) imagery has been approached.The results of reflectance spectrum measurement show that the absorption features of different rocks are all present from the electronic transitions and vibrations of the ferro ions, hydroxyl, molecular water, and carbonaceous ion in the constituent minerals. The results of X ray diffraction analysis and thin section identification show that the dinerals are mainly calcite,dolomite, chlorite, and hematite etc., and most of the minerals appear in the rocks as main component or impurity and cement. According to the spectral renectance features of the minerals, the authors pointed out that the band ratio images, such as TM3/1, TM2/3, TM4/3, and TM7/5, can extract the lithostratigraphic information of different rocks in the study area effectively.By analysing the imagery features of different rocks using a ratio colour composite image, which was superimposed on the TM4 single band image, the authors also presented the results of lithostratigraphic interpretation of the study area, which has shown a good potential for extracting lithostratigraphic information by using TM image data.