Lithological discrimination based on Landsat-9 OLI sensor and field observation data: The bana an-orogenic volcano-plutonic ring complex, West Cameroon line.

The western region, encompassing the an-orogenic Bana volcano-plutonic ring complex in Cameroon, underwent comprehensive exploration involving remote sensing analysis, fieldwork investigations, petrographic, and volcanological studies. The primary objective of this work was to integrate remote sensing analysis, fieldwork, and laboratory studies to achieve accurate lithological mapping for future prospective mineral explorations in the study area. Field relationships among co-occurring rock units in the area were examined, utilizing Landsat-9 OLI data. Petrographic analysis, including the use of a polarizing microscope, was conducted on various rock units (15 samples), along with volcanological processes studies. Operational Land Imager (OLI) images of Landsat 9 were processed using algorithms including False Colour Composite (FCC), Decorrelation Stretch (DS), Band Ratio (BR) composite, Principal Component Analysis (PCA), Spectral Angle Mapper (SAM) and Constrained Energy Minimization (CEM) methods to identify distinct rock units in the Bana ring complex. As a result, the later methods permitted to identify the petrographic units of the ring complex, which primarily comprise a volcano-plutonic sequence, along with metamorphic rocks like gneisses. The volcanic units include variety of basalts, trachytes, rhyolites and volcanic tuffs, while the plutonic units including gabbros, diorites, syenites and fine-grained granites. The findings of this study accurately at 99 % have permitted to newly setup a geologic map of the study area with implications for future mineral explorations.

Fuzzy-logic technique for gold mineralization prospecting using Landsat 9 OLI processing and fieldwork data in the Bibemi goldfield, north Cameroon.

Identifying potential hydrothermal alteration areas is indeed an essential method for mineral exploration. In this research, we developed an algorithm for the delineation of alteration mineral deposits related to gold mineralization in the Bibemi region using set of criteria derived from Landsat 9 OLI data using false colour composites, band ratios, principal component analysis, spectral angle mapper, and fuzzy-logic overlay methods. The methods used showed iron-oxides, ferrous, and hydroxyl-bearing and carbonate mineral properties related to gold mineralization. The fuzzy overlay map identified regions depending on their mineralization prospective, serving as foundation for prospective mineral deposit evaluation investigation, which was produced by the merging of band ratios and PC's alteration markers labelled very good, and excellent and encompasses 0.8-0.9, 0.9-1.0 respectively. The identified regions fit gold mineralization zones based on their potential as proven by prior and field research. In addition, lineaments analysis showed the presence of three main structural direction impacting the Bibemi region (N-S, NNE-SSW, and ESE-WNW to SSE-NNW), when merged with identified rock formations permits the possible deposition of mineral deposits. The innovative aspect of this research is the integration and processing of Landsat 9 OLI and fieldwork data, which allows for the identification of potentially mineralized rock formations and defining exploration targets.