北山方山口地区典型蚀变岩矿的光谱特征研究

利用遥感数据提取蚀变矿物的基础就是熟知不同岩石和矿物的光谱吸收特征，尤其是要掌握不同物理、化学环境下岩石和矿物的光谱变异特征。北山方山口地区地质演化历史复杂，蚀变岩石类型多样。那么不同岩石和矿物的光谱吸收特征有何特点，跟遥感影像上对应端元的光谱曲线是否吻合呢?另外，何种采集条件下获取的地面岩矿光谱最具代表性呢?就上述问题，笔者对方山口试验区内典型岩矿的光谱特征展开研究。实验结果表明：原位露头岩石样品和原地碎石样品与岩石标样在光谱曲线特征上最为接近，样品表层的沙漠漆对特征峰的吸收深度有一定影响。而岩矿的可见光-近红外光谱主要取决于矿物的成分和分子结构，岩石的物理破坏作用不会导致特征谱带的变化。各蚀变岩石影像端元光谱曲线与其实测光谱曲线所反映的曲线形态和吸收峰位置基本一致，但不同蚀变岩石的光谱曲线相似性很高，因此仅利用遥感影像难以准确识别出蚀变岩石的类别，但利用遥感图像提取含Fe2+、Fe3+、OH-、CO32-离子或离子基团的蚀变矿物具有较好的可行性。这对遥感蚀变矿物信息的提取起到了理论指导作用。

Spectral Characteristics of Typical Altered Rocks and Minerals from Fangshankou Area in Beishan

The basis of using remote sensing data to extract the altered minerals is to know the spectral absorption characteristics of different altered rocks and minerals. In particular, we need to master the spectral variation characteristics of rocks and minerals in different physical and chemical environments. The Fangshankou area in Beishan has complex geological evolution history, where developed various types of altered rocks. So, what are the characteristics of spectral absorption characteristics of different rocks and minerals, and is it consistent with the spectral curves of the corresponding terminal elements on remote sensing images? In this paper, the related research has been carried out. The experiment results show that the spectral curve of outcrop rock sample and crushed stone samples are the most closely related to the standard sample. In addition, the desert varnish on the surface of the sample has a certain effect on the absorption depth of the spectral characteristic peak. However, the physical destruction of rocks cannot lead to changes of the spectral. By analyzing the spectral characteristics of typical altered rocks, it's found that the altered rocks in this study area contain alteration minerals with Fe2+, Fe3+, OH-, CO32- ions and groups. The remote sensing spectral curves of altered rocks and their measured spectral curves have roughly the same characteristics. However, due to the high similarity of the spectral curves of different altered rocks, it is quite difficult to identify the types of alteration rocks accurately and effectively by using remote sensing images only. These results will provide a theoretical guidance for the extraction of remote sensing altered minerals.