Detection and Mapping Distribution of Iron Ore Mineralization Using Aster and Sentinel−2 Msi Data in Sekota District, Northern Ethiopia
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Date
2024-05-25
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Addis Ababa University
Abstract
Iron plays a vital role in fueling the economic development and technological advancement of a country. Despite Ethiopia, being endowed with a large amount of iron ore resources in different parts of the country, prospective zones are not delineated properly. Therefore, this research aims to identify the iron ore prospective zones in the Sekota district of Ethiopia utilizing ASTER and Sentinel 2B satellite data for further onsite exploration and testing. In addition, powder diffraction analysis was conducted to determine the type of iron ore. The image processing techniques such as band ratio, ASTER band 2/band 1 (ASB2/B1) and Sentinel 2 band 4 /band 2 (S2B4/B2), principal component analysis (PCA), and subpixel level mapping techniques including linear spectral unmixing (LSU) and mixture-tuned matched filtering (MTMF) were used to map hematite abundance. ASTER band 4/ band 5 (ASB4/B5) and Sentinel 2 band 11/band 12 (S2B11/B12) ratios were also used to map the distribution of lateritic iron. ASB2/B1 and S2B4/B2 band ratios mapped hematite iron ore covering an area of 102.5 and 97. 68 km2 respectively. ASB4/B5 band ratio detected 138.46 km2 of lateritic iron and the S2B11/B12band ratio delineated a comparably 168.13 km2 area. The selected PC4 of ASTER delineated hematite mineralized zones covering 133.40 km2 and Sentinel 2 PC3 of 110.70 km2 area. A very high match was found between the extracted hematite endmember and USGS resampled hematite spectra. The spectral fit was 0.74 for ASTER and 0.86 for Sentinel 2. Hematite anomaly zones were identified with MTMF and LSU techniques using these endmembers in different parts of the study area. Powder x-ray diffraction analysis revealed high hematite phases ranging from 36.8%−85.5% of Fe2O3. A strong positive correlation between was found S2B4/B2 and S2B4/B2 (r=0.83), ASB2/B1 and ASTER PC4 (r=0.94). Moderate correlations for ASB2/B2, S2B4/B2 (r=0.44), PCA (r=0.44), ASTER and Sentinel−2 MTMF (r=0.36). Results of both datasets show comparable areal coverage and overlay with three of the existing known iron occurrence polygons. Techniques employed in this research were effective in narrowing hematite mineralized potential zones for further exploration and can be used in other localities.
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Band Ratio, PCA, Endmember Collection, MTMF, XRD