We used Airborne Visible Infrared Imaging Spectrometer-Next Generation data for mapping possible mineral alterations, which aid in mineral exploration over larger areas. The data were subjected to various advanced processing techniques like Minimum Noise Fraction, Pixel Purity Index, N-Dimensional visualization and Spectral angle mapper classification. End-member spectra were matched with those of the minerals as available in the United States Geological Survey Spectral Library. In the present study, the Ambaji–Deri area of northwestern India was mapped for mineral alterations. The area has thick forest cover along with rugged topography, which warranted the use of hyperspectral remote sensing approach. The minerals such as calcite, muscovite and chlorite have been mapped, which are showing a good correlation with the ground geological records, barring epidote, whose distribution is scattered. We attribute the possible reason to be the spectral similarities between epidote and chlorite, which makes them difficult to differentiate only on the basis of the present hyperspectral study. The hyperspectral technique, as illustrated, provides powerful tool for mapping mineral alteration to mineral deposits. This enables scrutiny of a wider area of interest to being narrowed down for first-hand field investigations.

中文翻译：

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使用高光谱遥感评估安巴吉-德里地区（印度西北部）的矿物变化

我们使用机载可见光红外成像光谱仪-下一代数据绘制可能的矿物蚀变图，这有助于更大区域的矿物勘探。数据经过各种先进的处理技术，如最小噪声分数、像素纯度指数、N 维可视化和光谱角映射器分类。端元光谱与美国地质调查局光谱库中提供的矿物光谱相匹配。在本研究中，印度西北部的 Ambaji-Deri 地区绘制了矿物蚀变图。该地区有茂密的森林覆盖和崎岖的地形，这需要使用高光谱遥感方法。已测绘方解石、白云母、绿泥石等矿物，与地面地质记录有较好的相关性，除非绿帘石，其分布是分散的。我们将可能的原因归因于绿帘石和绿泥石之间的光谱相似性，这使得仅基于目前的高光谱研究难以区分它们。如图所示，高光谱技术为将矿物蚀变映射到矿床提供了强大的工具。这使得可以对更广泛的感兴趣领域进行审查，从而缩小范围以进行第一手实地调查。