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<p>Progress in mapping and geomorphic modelling has promoted interest on surface processes and mineral exploration with a&#xa0;focus on lateritic duricrusts over tropical shields. Landsat 8 Operational Land Imager (L8-OLI) and Copernicus (COP-30) digital elevation model have been combined with the geomorphological and geochemical characteristics of lateritic surfaces to provide an accurate distribution of their preserved duricrust at Minim-Martap. Band ratios (BR) and image algebra were used to delineate bauxite duricrusts (Al-bearing surface), erosional slopes, pediment duricrusts (Fe-bearing) and alluvial plains. Predictivity maps were determined by the band 4/band 2 (BR1), (band 4 + band 6)/band 5 (BR2) band ratios, lateritic index (LI) and principal component analysis (PCA). Correlation between BR2, PC4 and reliable constraints (petrology, altitudes, geomorphology, geochemistry) allowed thresholding in a Boolean logic to extract and validate favourable areas of duricrust landscapes. Results depict an accuracy of 92% confidence upon mapping bauxites and pediments with BR2. For the alluvial plains, PC4 results demonstrate their extension over the entire study area. The effectively moderate duricrust preservation (31%) and the spatial/dynamic consistency of the final map in a RED modelled sequence of lateritic residium (R), erosional slopes (E), and depositional terrain (D) ascertain capabilities of Landsat 8 OLI and reliable constraints to depict stages of laterites differentiation. The study also determines patterns of structurally constrained incisions over Minim-Martap landscapes and dissection/dispersion scenarios on rolling pediplains. The pioneering map issued is an asset towards understanding regolith-erosion-pediment associations, which are proxies for mineral resource classification, past-climate and landform reconstruction scenarios in Cameroon.</p>

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LANDSAT-8/OLI Classification and Geomorphic Analysis in Mapping Bauxites and Pediments Lateritic Duricrusts of Minim-Martap, Adamaoua-Cameroon

  • 期刊论文

  • 发表日期：

    2025年4月9日

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  • Alex Fotso Kengne,
  • Mathieu Momo Nouazi,
  • Paul Tematio,
  • Romaric Ntchantcho,
  • Roland William Edima Yana,
  • Ethel Ashukem Nkongho,
  • Salomon Cesar Nguemhe Fils,
  • Gatien Romuald Kenfack Nguemo,
  • Donnald Hermann Fossi,
  • Marie Alex Chimeu Akaba,
  • Rachel Ngo Nyouma

摘要

Progress in mapping and geomorphic modelling has promoted interest on surface processes and mineral exploration with a focus on lateritic duricrusts over tropical shields. Landsat 8 Operational Land Imager (L8-OLI) and Copernicus (COP-30) digital elevation model have been combined with the geomorphological and geochemical characteristics of lateritic surfaces to provide an accurate distribution of their preserved duricrust at Minim-Martap. Band ratios (BR) and image algebra were used to delineate bauxite duricrusts (Al-bearing surface), erosional slopes, pediment duricrusts (Fe-bearing) and alluvial plains. Predictivity maps were determined by the band 4/band 2 (BR1), (band 4 + band 6)/band 5 (BR2) band ratios, lateritic index (LI) and principal component analysis (PCA). Correlation between BR2, PC4 and reliable constraints (petrology, altitudes, geomorphology, geochemistry) allowed thresholding in a Boolean logic to extract and validate favourable areas of duricrust landscapes. Results depict an accuracy of 92% confidence upon mapping bauxites and pediments with BR2. For the alluvial plains, PC4 results demonstrate their extension over the entire study area. The effectively moderate duricrust preservation (31%) and the spatial/dynamic consistency of the final map in a RED modelled sequence of lateritic residium (R), erosional slopes (E), and depositional terrain (D) ascertain capabilities of Landsat 8 OLI and reliable constraints to depict stages of laterites differentiation. The study also determines patterns of structurally constrained incisions over Minim-Martap landscapes and dissection/dispersion scenarios on rolling pediplains. The pioneering map issued is an asset towards understanding regolith-erosion-pediment associations, which are proxies for mineral resource classification, past-climate and landform reconstruction scenarios in Cameroon.