基于ASTER数据的蚀变矿物信息提取——以哈密黄山铜镍矿区为例

The Extraction of Altered Mineral Information Based on ASTER Data:A Case Study of the Huangshan Copper-Nickel Ore District in Hami

在分析哈密黄山铜镍矿区典型地物波谱特征的基础上,设计了基于ASTER数据的蚀变信息提取流程,详细论述了对4组含不同离子或基团的常见蚀变矿物应用主成分分析(PCA)进行蚀变信息提取、采用光谱角制图法(spectral angle mapper,SAM)进行干扰异常筛选的"SAM去干扰异常主分量门限技术"。4组(9种)蚀变矿物包括:含Fe离子的矿物(针铁矿、赤铁矿)、含CO23-基团的矿物(方解石、白云石)、含Al-OH基团的矿物(白云母、蒙脱石、高岭石)以及含Mg-OH基团的矿物(绿泥石、绿帘石)。蚀变矿物信息提取结果表明,"SAM去干扰异常主分量门限技术"方法可行,对ASTER数据的应用效果与实际情况比较吻合,充分证明ASTER在短波红外范围内具有很强的矿物刻画能力。

Choosing the Huangshan copper-nickel ore district as the study area and ASTER data as the data source,the authors analyzed the spectral characteristics of the typical features in ASTER bands,designed the process of extraction of alteration information,and discussed in detail ＂de-interfered anomalous principal component thresholding technique based on spectral angle mapping（SAM）＂,which was applied to the four groups of common altered minerals containing different ions or groups,and the technique included the extraction of the alteration information by principal component analysis（PCA）and de-interfered anomaly by SAM.The four groups of common altered minerals are as follows：minerals containing Fe ion（goethite and hematite）,minerals containing CO2-3 group（calcite and dolomite）,minerals containing Al-OH group（muscovite,montmorillonite and kaolinite） and minerals containing Mg-OH group（chlorite and epidote）.The results of extraction show that the way of ＂de-interfered anomalous principal component thresholding technique based on SAM＂ is feasible and the result is consistent with the reality.It is proved evidently that ASTER data have great capability of depicting minerals in the short wave infrared range.