使用光谱学的矿物制图-从实地测量到机载卫星成像光谱

矿物物理学决定了岩石和土壤在电磁波谱上的外观。在可见光/近红外(VNIR)和短波红外(SWIR)中，许多材料吸收特定波长的辐射，允许通过吸收特征的位置和特征来识别它们。波长小于1.0微米的电子过程可以识别含有Fe+3的矿物。分子振动特征在~1.0和2.5微米波长是含有阴离子基团的矿物的诊断，如Al-OH, Mg-OH, Fe-OH, Si-OH, CO3, NH4和SO4。吸收带位置和形状的微小差异与矿物成分的差异和变异性有关。自20世纪80年代初，成象光谱技术就开始应用于基于光谱特征的二维矿物分布制图。地质应用包括岩性测绘等领域;贵金属和贱金属勘探;以及石油、天然气和地热能的勘探。场光谱在成像光谱仪数据的校准、分析和验证中起着至关重要的作用。 Spectral libraries have been measured for a variety of minerals. Imaging spectrometer datasets have been acquired around the world using airborne platforms and recent satellite systems provide spectral measurements for selected areas. Case histories will be presented demonstrating the link between laboratory, field, and imaging spectrometer data. Selected physics-based analysis methodologies will be discussed and the level of information available from the data will be demonstrated. Examples will include mineral identification and mapping in the context of hydrothermal alteration associated with active and fossil hot springs and mineral deposits. Specific mineral mapping examples will include hematite, goethite, and jarosite in the VNIR and identification and separation of calcite, dolomite, and calc-silicates along with phyllosilicates and sulfate minerals such as alunite and jaorsite using SWIR spectroscopy. Spectral variability caused by processes such as anion substitution in illite/muscovite, crystallinity in kaolinite-group minerals, and spectral mixing will also be discussed.