Remote sensing is a robust and useful tool for providing high‐resolution image data and enabling reliable geological mapping during the initial stage of mineral exploration. One of its main applications is the extraction of lineaments and to locate alteration areas to target gold exploration. It has been long used in the Pan‐African belt of Cameroon to identify a hydrothermal alteration and a great number of lineaments associated with mineralizations. The study area located in the Pan‐African belt hosts numerous alluvial gold deposits where the primary mineralization was still largely poorly unknown until now, due to deep weathering. Therefore, remote sensing combined with field data is useful for targeting potential zones of primary gold resources involved in the hydrothermal and lineament systems. In this study, remote sensing data from Landsat 8 imagery were selected to map the distribution of hydrothermal minerals, and gravity data were interpreted for highlighting structural patterns related to the control of high‐potential zone for gold mineralization, generating a mineral prospect map. The lineaments network shows directions ranging from ENE‐WSW to E‐W, with main direction N45° and a secondary striking N275°. Image enhancement/processing techniques included the application of band ratio and principal component analysis that were helpful to demarcate potential alteration zones marked by iron oxide/hydroxides in which haematite and pyrite are used as proximal alterations and hydroxyl‐bearing minerals in which sericite (muscovite) is used as a marker of proximal alteration, while chlorite, epidote, biotite, quartz, and calcite are used as distal alteration zone, as described by field and petrographic data. The identified alteration zones display a high consistency with the known locations of gold occurrences (mining sites) and closely concordant with large‐scale gold mineralization in the study area. This study presents an integrated approach of Landsat 8 imagery with gravity data and field data for discovering primary mineral resources in a deep weathering area.

A geological based remote sensing study was carried out over the Poli group in Garoua (northern Cameroon), renowned for its hydrothermally occurring mineralizations (Gold and Uranium). In this study, Landsat 8 OLI/TIRS coupled with magnetic data were used in order to realize a regional litho-structural mapping of hydrothermal alteration targets, required for mineral exploration. Hence, the enhancement of both Landsat 8 and magnetic data was achieved via digital image processing (DIP) techniques notably Band rationing (BR), Principal Component Analysis (PCA), Horizontal gradient (HG), and lineament extraction algorithms. Based on reference band ratio combinations (Sultan's and Kaufmann's) and Crosta Technique (PCA analysis), hydrothermally altered minerals such as hydroxyl-bearing minerals and iron oxides were identified. The PCA map was shown to better illustrate hydrothermally altered areas than Band ratios. Thus, a classification map emphasizing on mineral targets was obtained from the PCA map. Besides, the CET grid analysis tool (horizontal gradient) from Geosoft software 8.4 and the line algorithm (pan band 8) from Geomatica 2013 allowed the extraction of subsurface and surface lineaments respectively. The resulting lineaments showed a predominant E-W trending direction, which suggests a major tectonic event having prevailed within the area. Other directions include NE-SW/ENE-WSW, and N-S. The generation of a target exploration map, via ArcGIS 10.4.1, was performed by the overlay of hydrothermal alteration mapping and structural mapping. New regional maps, providing a useful insight for further mining exploration, were obtained.

In mineral exploration, detailed hydrothermally altered minerals mapping is an important approach prior to the field campaign. The study area contains several gold‐bearing quartz veins associated with hydrothermally altered zones rich in sulphides, muscovite/sericite, iron oxides, and hydrous silica. In this study, Aster 07XT, Landsat 8, and aeromagnetic data were integrated to detect potential zones associated with gold mineralization in Northern Cameroon. For this purpose, the relative band absorption depth, band ratioing, and analytic signal techniques were applied to enhance, identify and map hydrothermal alteration minerals, that is, hydroxyl‐bearing, iron oxide/hydroxide. In addition, a semi‐automatic approach was applied to extract remotely sensed and aeromagnetic lineaments from PCI Geomatica and Centre for Exploration Targeting Grid Analysis respectively. Hence, several potential mining targets were delineated from the processing of both remote sensing and aeromagnetic data. The major directions of the lineaments affecting the area include NE–SW/ENE–WSW, E–W, and N–S. Detailed field campaigns, petrographic analyses, and spectral measurements of rock samples were carried out in Tchollire and environs to verify the results from remotely sensed data. The analytical observations indicated the presence of quartz, epidote, chlorite, magnetite, haematite, sericite, galena, sulphide, telluride minerals, etc. Moreover, the target hydrothermal alteration zones were proved to be spatially associated with known mining areas and gold occurrences in the study area. Consequently, new prospective mining areas have been designated. This study confirmed the reliability and applicability of the processing of satellite imagery in mineral exploration in Northern Cameroon. It is suggested that the dataset used in this study provides a suitable tool for mapping hydrothermal alteration minerals linked to gold deposits and can be applied in other provinces with similar geological settings.

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