Hyperspectral Signatures of Minerals From the TUNL Library for Geological Mapping: Clays, Sulfur and Iron Minerals

Mineral exploration employs various techniques such as geological, geochemical, geophysical, and drilling methods. In contemporary exploration, hyperspectral remote sensing has proven to be particularly effective. The objective of this study is to enrich the TUNL (TUNisian Library) spectral library of minerals within the Tunisian mining context, initiated by Mezned [1] and expanded upon by Alayet [2]. The focus of this work lies in the analysis of spectral responses for the characterization of iron mineral surfaces and clays, establishing VNIR/SWIR spectral signatures at different particle size scales. As a result of our analysis, hematite, goethite, kaolinite, and montmorillonite were successfully identified spectrally. Additionally, sulfur was detected based on a distinct spectral absorption feature in the VNIR region. The purity of various clay minerals and iron oxides/hydroxides was also considered. The mineralogical compositions confirmed by X-ray diffraction (XRD) analysis align with the presented results. A comparative analysis with public spectral libraries, USGS and JPL, was conducted, with future plans to further enrich the TUNL library. The establishment of a geoportal, showcasing and providing data from the TUNL spectral library, holds significant importance. These advancements will be crucial for a more profound understanding of the mineralogical composition of the studied sites and geological mapping.