University of Twente Student Theses


Discrimination of individual Iron-bearing minerals with the Sentinel-2 Super-Spectral Imager

Umar, Nazif (2023) Discrimination of individual Iron-bearing minerals with the Sentinel-2 Super-Spectral Imager.

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Abstract:Iron-bearing minerals such as jarosite, goethite and hematite act as proxies, indicating the presence of underlying mineralization with high economic potential, especially in areas where valuable ore deposits may be concealed beneath the sediments. Consequently, mapping of these minerals using multispectral satellite imagery has been a subject of research for several decades. Geological Remote Sensing techniques, such as band ratio, are valuable in iron mineral mapping because they effectively emphasize the spectral signatures of specific minerals. Iron minerals exhibit distinct absorption features in the VNIR spectral range, making it crucial to have a multispectral sensor with high spectral resolution at the VNIR to identify and discriminate them. Sentinel-2, a high-resolution satellite sensor, with multiple narrow bands at the VNIR compared to the fewer bands of ASTER and Landsat 8 at the VNIR is employed for this study. Twenty-nine high-resolution spectra collected from the created synthetic minerals were resampled to Sentinel-2 resolution. Existing band ratios were tested to evaluate whether they discriminate between iron minerals or not. Subsequently, the shortcomings of the existing band ratios led to the development of novel band ratios. Iron-bearing mineral distribution in a real-world setting was explored using novel band ratios. The distributions of hematite and goethite were determined using band ratios (B4/B3) and (B3/B2), respectively, with significant matching to a published hyperspectral map. However, discrepancies become evident in discriminating jarosite using the (B5+B11)/B12 ratio, potentially due to overwhelming absorption features from other minerals. The combination of the band ratios into a composite enhanced the discrimination. The findings show the success of the proposed band ratios in identifying hematite and goethite minerals and highlights the significance of integrating band ratios as composite in mineral discrimination. In addition, this research has successfully produced high-quality spectra of iron minerals thereby adding to the existing spectral libraries and can be used as reference for future studies. Finally, this study highlights the challenges related to interaction of iron minerals with minerals in real world, making discrimination difficult.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Subject:38 earth sciences
Programme:Geoinformation Science and Earth Observation MSc (75014)
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