Figure 9 - uploaded by Mary Immaculate Fru
Content may be subject to copyright.
![Landsat 8 band ratio 7/5, 5/4, 6/7 in RGB [1] of the study area](profile/Mary-Immaculate-Fru/publication/342096590/figure/fig3/AS:913188044423168@1594732404132/Landsat-8-band-ratio-7-5-5-4-6-7-in-RGB-1-of-the-study-area.png)
Source publication
![Figure 9. Landsat 8 band ratio 7/5, 5/4, 6/7 in RGB [1] of the study area](profile/Mary-Immaculate-Fru/publication/342096590/figure/fig3/AS:913188044423168@1594732404132/Landsat-8-band-ratio-7-5-5-4-6-7-in-RGB-1-of-the-study-area_Q320.jpg)
Abstract 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 ta...
Contexts in source publication
Context 1
... Kaufmann's band ratio combinations 7/5, 5/4, 6/7 in RGB (Figure 9) illustrate vegetation zones in green (ratio 5/4), while water (drainage pattern) is represented in dark blue. Ferric and ferrous iron depicted by band 7/5 are expressed in pink color. ...
Context 2
... Kaufmann's band ratio combinations 7/5, 5/4, 6/7 in RGB (Figure 9) illustrate vegetation zones in green (ratio 5/4), while water (drainage pattern) is represented in dark blue. Ferric and ferrous iron depicted by band 7/5 are expressed in pink color. ...
Similar publications
ABSTRACT
This study analyses the influence of extreme precipitation and flood amplification on the spatial and temporal level at the IRAD Multipurpose Station of Foumbot (IMSF) from a hydro-climatic and anthropogenic approach. The processing and analysis for 20 years of rainfall data allowed the measurement and the extent of the phenomenon in the...
Snails are an emerging problem in banana production in Cameroon due to the damages caused on the banana fruits. They attack the banana fruits resulting in aesthetically disfigured fruits. This study was carried out to compare the effectiveness of selected
agrochemicals in the laboratory and the field for the control of the snails. The agrochemical...
Citations
... Among those models, Earth Magnetic Anomaly Grid version 2 (EMAG2v2) data have mostly been utilised for DBML estimations in several areas such as: in the north China (Xu et al. 2017), in Turkey (Pamuk 2019;Pamuk and Özsöz 2022), in the Adamawa region, Cameroon (Njeudjang et al. 2020(Njeudjang et al. , 2022, and in the whole African continent (Mohamed and Al Deep 2021). Other studies were based on the extraction of tectonic structures from the interpretation of EMAG2v2 data (Basseka et al. 2016;Anaba Fotze et al. 2019;Cheunteu Fantah et al. 2022;Njeudjang et al. 2022). On the other hand, Earth Magnetic Anomaly Grid version 3 (EMAG2v3) data have been utilised for DBML and/or thermal structure investigations (Njiteu Tchoukeu et al. 2021;Lei et al. 2022;Solano-Acosta et al. 2022) and for tectonic structures enhancement as well (Lei et al. 2022;Solano-Acosta et al. 2022;Som Mbang et al. 2023). ...
Global geomagnetic models are a compilation of existing magnetic data which were reprocessed and freely made available as 2 or 3 arc minute resolution grids at 0-km or 4-5-km altitude relative to the geoid. Thus, many researchers rely on those data due to their open access. This study aims at evaluating freely released global geomagnetic models with respect to aeromagnetic data which are the original data, usually subjected to third party or commercial restrictions in Cameroon. Hence, both global geomagnetic models and aeromagnetic data were sampled along 4 profiles for assessment. The extracted data were analysed using Pearson's correlation coefficient depicted in tables. The Power Spectrum Density curves of both aeromagnetic and their respective global geomagnetic grids were computed and displayed as graphs. The results show that the so-claimed 4-5-km altitude relative to the geoid of global geomagnetic models is heterogeneous in Cameroon since the spectral content of those models vary from 5-20 km. Besides, considerable discrepancies were observed with Earth Magnetic Anomaly Grid version 3 (EMAG2v3) data, indicating that they are not reliable for scientific studies based in Cameroon. This study provides insights on global geomagnetic models and could aid in optimizing the use of those models in Cameroon. ARTICLE HISTORY
... The eigenvector matrix shows the statistical correlation between the PCs (dependent variables or lines) and the input image strips (independent variables or columns). In CP4, the negative contributions of bands 1, 2, 4, 5, and 6 and positive contributions of the other bands (3,7,8,9) highlight the distribution of high-reflective minerals in bands 3, 7, 8, and 9, such as iron oxide and kaolinite. Concerning iron oxide, the ratio of the band that allows us to map the area rich in this mineral is the division of band 3 and band 4. According to the table, we can see that the CP4 has positive pixels of band 3 and negative of band 4. Thus, the iron oxide present by clear pixels in the CP4 and CP5 formed a positive contribution from bands 3, 4 and 7, with minerals having strong reflectance in bands 3 and 5, and absorption in the other bands, that are ferrous silicates and carbonates. ...
IMITER is an area in Morocco which is considered to be the most important zone for silver exploration. It is characterized by two units: an upper Neoproterozoic volcaniclastic unit and a basal sedimentary unit alternating with Neoproterozoic pelite and sandstone levels, which carry silver mineralization. Remote sensing is the science of obtaining information about an area by analyzing data, such as satellite images, collected by a device or sensor without direct contact with the object studied. Several techniques are used on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite image: image transformation techniques, such as band ratios, principal component analysis, and unsupervised classification, which are used to successfully identify hydrothermal alteration zones in the area of study. These techniques have been used to contrast the different lithologies and areas of high concentrations of mineral assemblages resulting from alteration of kaolinite, carbonate, oxide iron, Fe³⁺, and ferrous silicate. A comparison between the results obtained and the high-resolution aeromagnetic geophysical data showed the presence of these alterations in the area. The results indicate several areas with high mineralization potential in the study area that can be considered for future systematic exploration programs. The current study showed that ASTER image processing and remote sensing techniques are valuable mapping tools for recognizing hydrothermal alteration areas by providing accurate preliminary maps and cost-effectiveness.
... GIS predictive modelling is ideal for exploration studies because it allows for the accurate evaluation of various geospatial data while identifying promising mineralization zones. The use of spatial data can be well integrated using empirical or conceptual models (Abate Essi et al., 2019;Anaba Fotze et al., 2019;Binam et al., 2018;Dehnavi et al., 2010;Hung et al., 2005;Lysytsyn, 2015;Neh-Fru et al., 2020;Pour et al., 2017aPour et al., , 2017bPour et al., 2021;Sadiya et al., 2015;Traore et al., 2020). The selection of these models in evaluating mineral deposit occurrences is based on specific factors such as known geological occurrences of existing mineral deposits. ...
... The late Pan-African granites which dominate this domain were then emplaced mainly along the transcurrent shear zones of Central Cameroon. Evidence of rifting along these shear zones lies in the presence of a Neoproterozoic syn-tectonic pull-apart basin (Lom Basin) with low to high grade greenschist facies, metavolcanic and metasedimentary rocks (Tchameni et al., 2006;Tchakounté et al., 2017;Abate Essi et al., 2019;Anaba et al., 2019;Ndonfack Azeuda et al., 2022). Younger plutonic and volcanic rocks (65 Ma and younger) encountered within this domain are known to be part of the Cameroon Volcanic Line (CVL) (Burke, 2001;Elsheikh et al., 2014;Marzoli et al., 2000;Nana et al., 2021). ...
Regional scale mineral resource exploration is best accomplished through the use of Remote Sensing (RS) and Geographic Information System (GIS) techniques. Prospective sapphire zones in Belel and its environs (northern Cameroon) were identified in this study by integrating spatial data representing geological, geomorphological, and alteration types. The Predictive Area Curve (PAC) analysis was also used to assess the statistical relationship between the evidential data and known sapphire mineralization occurrences. To integrate geospatial data and generate mineral favourability maps for sapphire mineralization, a multi-criteria weighted sum model was used. The mineral potential maps were then discretized using multi-fractal analysis, and the Receiver Operating Curve/Area Under Curve (ROC/AUC) analysis was used to evaluate the accuracy levels for the GIS predictive model. According to PAC analysis, spatial data on proximal distances to first order streams (78%) and curvature (72%) show the strongest correlation with existing sapphire mineralization. The correlations are lowest for quartz content (67%), ferrous iron content (66%) and proximity to host rock (53%). GIS predictive map based on the Weighted Sum Model (WSM) displayed a high favorability for sapphire mineralization within the eastern and south eastern parts of the study area. The multi-fractal analysis segregated the predictive model into 4 classes. Zones of high and very high favourability or sapphire mineralization accounted for 52% of the study area. Statistical validation using ROC/AUC analysis suggests that WSM has a high prediction accuracy of 81.3%. The Weighted Sum Model's dependability attests to its usefulness as a prospecting technique.
... This not only aids visualization and interpretation, but also helps to map detailed alteration zone for narrowing down the exploration target. Although, large-scale alteration zones can be easily mapped with moderate resolution multispectral data such as landsat series: Multi Spectral Scanner (MSS) (Abrams et al., 1983;Arribas et al., 1995;Chavez et al., 1980;Goetz & Rowan, 1981;Goetz et al, 1983;Rowan et al., 1974Rowan et al., , 1977, Thematic Mapper (TM) (Abdelsalam et al., 2000;Ferrier et al., 2002;Gad & Kusky, 2006;Sabins, 1999), Enhanced Thematic Mapper (ETM) (Masoumi et al., 2017a;Mia & Fujimitsu, 2012;Pour et al., 2013;Van der Meer et al., 2012), Operational Land Imager (OLI) (Fotze et al., 2019;Frutuoso et al., 2021;Masoumi et al., 2017a;Pour & Hashim, 2015;Prasath & Kusuma, 2018;Zhang et al., 2016), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) (Kumar et al., 2015;Maiti, 2018b, 2021;Masoumi et al., 2017b;Pour et al., 2013;Rajendran & Nasir, 2019;Mars & Rowan, 2006;Sengupta et al., 2019) as documented by several researcher but it is difficult for vegetated zone with small-scale geological outcrops. Vegetation presence in such regions hinders the information partially of the underlying geological material (Mahanta and Maiti, 2018b;Pour et al., 2013). ...
WorldView-3 sensor with higher spectral and spatial resolution provides greater opportunity to map the hydrothermal alteration zones. Advancement of remote sensing techniques have been manifold in the field of mineral and alteration mapping enabling subpixel level mineral identification. However, remote mapping of alteration zone in vegetated terrain still remains challenging. The present work is aimed at mapping of hydrothermal alteration zones in a sparsely vegetated terrain using high resolution WorldView-3 data. Minimum Noise Fraction (MNF), Spectral Information Divergence classification (SID) and Selective Principal Component Analysis (SPCA) techniques are used collectively for mapping different alteration zones. The alteration minerals mapping has been further supported by laboratory spectroscopy methods, field observation and petrographic microscopic study. A comprehensive analysis on the ability of different techniques to detect the alteration zone in a sparsely vegetated terrain named Lawa mines, North Singhbhum Mobile Belt has been documented in this paper. Image-derived reflectance spectra corresponding to field locations have been used for SID classification and an accuracy of 78% is obtained for the current study. The vegetation covered areas have been classified as vegetated using both MNF and SID techniques. Besides, the SPCA results have better highlighted all the alteration zones present in the area by suppressing the vegetation effects. While MNF provides a broad overview of the spectrally different litho-units, SID classification gives more detailed pixel wise classification of various rock types present and furthermore SPCA method highlights various alteration types present in the area. Therefore, combined MNF, SID and SPCA can provide a detailed alteration map of the sparsely vegetated region. Ferruginisation, silicification, sericitization, and chloritization types of alterations primarily observed in both mesoscopic and microscopic scale. Ferruginisation and silicification alteration are predominant types among all. These alterations are also evident in hosting mineralization of Au, Ag, Cu and Rare Earth Elements. Mineralization is primarily associated with various rocks, such as quartz vein, quartzite and talc chlorite sericite schist.
... Indeed, Remote Sensing techniques provide a synoptic overview of areas regardless of fieldwork constraints (climate conditions, politically unstable localities, inaccessible features, confined study area, etc.), thereby allowing a quick regional survey of both surface and subsurface targeted materials. In addition, the signal acquired from sensors (reflectance, magnetic susceptibility, density, resistivity, etc.) can be processed and interpreted based on the respective objectives and perspectives of different fields of research such as climate studies, natural hazards monitoring, water resources application, mineral exploration, etc. (Acharya et al., 2016;Anaba Fotze et al., 2019Forson et al., 2021;Frutuoso et al., 2021;Ketchaya et al., 2021;Traore et al., 2020;Yang et al., 2013). ...
... Iron oxides (haematite, goethite, jarosite) show diagnostic features in the VNIR bands (Abdelnasser et al., 2018;Ketchaya et al., 2021). On the other hand, hydroxyl-bearing minerals, and carbonates absorption features are best visualized in the SWIR bands (Anaba Fotze et al., 2019;Forson et al., 2021;Ketchaya et al., 2021;Neh-Fru et al., 2020;Pour & Hashim, 2014. ...
... Hydrothermally altered minerals and lineaments can be enhanced by remote sensing data processing (Anaba Fotze et al., 2019;Forson et al., 2021;Ketchaya et al., 2021;Pour et al., 2019;Pour, Park, Park, Hong, Hashim, et al., 2018a;Pour, Park, Park, Hong, Hashim, et al., 2018b;Pour, Park, Park, Hong, Zoheir, et al., 2018). Besides, the results from this data enhancement can serve as an important tool for the identification of potential mineral resources linked to hydrothermal alteration processes such as argilitization, sericitization, chloritization, silicification, etc. (Bolouki et al., 2020). ...
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. The study area contains several gold‐bearing quartz veins associated with hydrothermally altered zones rich in sulphides, muscovite/sericite, iron oxides, and hydrous silica. Despite the mining potential of the area, several zones remain unexplored. In this study, Aster 07XT, Landsat 8, and aeromagnetic data were integrated to detect potential zones associated with gold mineralizations in Northern Cameroon. For this purpose, the relative band absorption depth, band ratioing, and analytic signal (AS) techniques were applied to enhance, identify and map hydrothermal alteration minerals, that is, hydroxyl‐bearing, iron oxide/hydroxide. Besides, 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 intersection of all region of interest pixel points from argillic (314 942), phyllic (304 740), and propylitic (327 377) alteration minerals allowed the enhancement of 1077 pixel points which represent areas where argillic, phyllic, and propylitic alteration coincide. Hence, the 1077‐pixel points computed were considered potential mining sites. The extracted lineaments and 1077 potential ore deposits were superimposed on both the AS anomaly map (in purple) and the band ratio 4/2 image (iron oxides better enhanced in red with 20% transparency). We could denote that most of the 1077 potential mining sites fall either on the purple signal (representing high magnetic susceptibility areas due to magnetite, ilmenite, etc.) or on the red signal which is linked to iron‐bearing minerals such as haematite, goethite, jarosite, etc. Thus, there exists a positive correlation between the 1077 potential sites and iron oxide minerals. Besides, the structural features extracted from both remote sensing and magnetic data show a positive correlation with most of the 1077 potential sites enhanced. 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.
... However, the resulting images obtained from both band ratios 6/7 (for highlighting hydroxyl-bearing minerals) and the NDVI show a positive correlation of higher value pixels between both bands (Figure 10a,b). Indeed, vegetation hampers the detection of hydroxylbearing minerals (Anaba Fotze et al., 2019) due to the overlapping of band ratio 6/7 with the lignin-cellulose spectral band (Galvão et al., 2005). Hence, the need to remove NDVI from bands 6/7 is useful. ...
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. Regional lineaments from satellite images showing the spatial distribution, and high‐potential areas of gold mineralization in Gamba district.
... For this reason, they can be used for determination of clay areas and hydrothermal alteration zones. After 2013, similar studies were conducted using Landsat 8 (especially using OLI sensors) (Aryanmehr et al., 2018;Safari et al., 2018;Abdelmalik, 2019;Marc Anaba Fotze et al., 2019;Mia et al., 2019;Pour et al., 2019;Susantoro et al., 2020). ...
... It is used frequently for the detection of hydrothermal alteration and in researching possible mineralization in recent years (Cró sta & Moore, 1989;Ranjbar et al., 2002;Tangestani & Moore, 2000;Vural & Aydal, 2020;Vural et al., 2017). This technique can be applied to selected 4 or 6 bands (Abdul Sulemana et al., 2020;Al Kwatli et al., 2012;Cró sta & Moore, 1989;Liu et al., 2011;Marc Anaba Fotze et al., 2019;Mia et al., 2019;Rutz-Armenta & Prol-Ledesma, 1998;Vural, 2006). Considering that, depending to the purpose, the determination of hydrothermal alteration areas (e.g., clay occurrence areas, weathering areas) is of great importance in mineral exploration, one of the most important points to be considered in this type of study is selecting the right principal component (PC). ...
The clay areas in Gümüşhane (NE Turkey) were examined in mineralogical and geochemical terms, and by remote sensing methods. X-ray diffraction, scanning electron microscope and chemical analysis were completed on samples from 11 selected clay areas in the region. Within the scope of remote sensing, Landsat 7 and 8 satellite images of the region were processed with the Crósta technique to assess the clay areas. The Kale and Tamzı clays are contained within a Late Cretaceous turbiditic series. The clays in Canca, Refene and Çamlıca occur in intensively hydrothermally altered volcanic rocks of the Eocene Alibaba Formation. The other clay areas are in the Liassic Şenköy Formation consisting of a volcano-sedimentary series. The clays in the Şenköy Formation are generally below the coal levels. While mainly illite and lesser kaolinite were determined in Dörtkonak, Alemdar, Yukarı Kov and Çamlıca, the clays in Tahnis and Kabantaşı are smectite. Tekke, Canca and Refene clays are kaolinite with smaller amounts of illite, whereas Kale and Tamzı clays are mainly chlorite with lower content of illite–smectite interlayers. Illites in Dörtkonak, Alemdar, Yukarı Kov and Çamlıca are poor in iron and magnesium and formed by hydrothermal alteration of feldspars in the host rocks. Findings of the remote sensing studies using Landsat 7 and 8 datasets were compatible with the results obtained from field observations and general geological studies, and so it is concluded that the Crósta technique provided good results for exploration of clay occurrences and their determination in the region.
... Recent advances in alteration mapping have been centered on a more sophisticated spectral analysis technique [18][19][20], which is based on calculating the spectral similarity between the image spectra and reference spectral as well as determining the relative abundance of the material that are depicted on the satellite imagery [21]. In Cameroon, geological investigations have been limited to field, geochemical, petrographic and structural studies however, some researchers have attempted geological investigations using the remote sensing approach [22][23][24][25][26]. Mayo Kila is located within the Pan African mobile belt which is well known for its mineral potential [27,28]. ...
Remote sensing analysis is an essential and cost-effective reconnaissance tool in mineral exploration. This tool is meant to generate initial litho-structural data valuable in identifying areas that host mineralization. This data assist in designing intensive mapping in the area of interest. This is achieved by constraining the mapping to areas that host potential mineralization as evaluated from the remote sensing data. In this study we apply remote sensing technique in the Mayo Kila area known for its gem mineralization as attested by large artisanal workings as well as previous research in the area. However, there is paucity of geological data in the area. Remote sensing was therefore used to generate preliminary litho-structural and hydrothermal alteration data. This was achieved using Principal component analysis for lithological and alteration mapping and Digital elevation model for structural investigation. By applying principal component to band 1-5 and 7, six different lithologies were identified (1) Calc-alkaline monzonitic granite, (2) Migmatitic gneiss (3) Calc-alkaline potassic granite, (4) Basaltic rocks and (5) Hornblende-Biotite granite (6) Trachytes and Rhyolites. Selective principal component analysis on Landsat reveals the uneven distribution of hydrothermal alteration across the study area, while fractal analysis segregated high and low alteration zones. Lineament extraction and analysis suggest a dominant NE-SW structural trend accompanied by a subtle NW-SE trending direction. Alterations are confined to the NE-SW structures characterized by granitic intrusions. These intrusions are probably the source of the fluids responsible for hydrothermal alteration hence mineralization of the study area.
... Recent advances in alteration mapping have been centered on a more sophisticated spectral analysis technique [18][19][20], which is based on calculating the spectral similarity between the image spectra and reference spectral as well as determining the relative abundance of the material that are depicted on the satellite imagery [21]. In Cameroon, geological investigations have been limited to field, geochemical, petrographic and structural studies however, some researchers have attempted geological investigations using the remote sensing approach [22][23][24][25][26]. Mayo Kila is located within the Pan African mobile belt which is well known for its mineral potential [27,28]. ...
... The remote sensing results are consistent with magnetic results (Figure 9). These structures and directions are consistent with previous studies [25] [85] in the area and at the vicinities. Indeed, these works have highlighted many faults or fractures interpreted as tectonic accidents affecting the CC, the basement of the CAFB domain without providing a real explanation on the faulting history or kinematics to help understanding geodynamics at the northern margin of the CC. ...
A semi-regional study was carried out in the Yaounde-Sangmelima area, a densely vegetated tropical region of southern Cameroon located in the Central Africa Fold Belt (CAFB)/Congo Craton (CC) transition zone. Towards structural lineaments and predictive hydrothermal porphyry deposits mapping, an integrated analysis of Landsat-8 OLI data, aeromagnetic, geological and mineral indices maps was performed. The Remote sensing using False colour composite images involving bands combinations and Crosta method (features oriented principal components analysis) enabled the mapping of the gneisses and schists domains without a clear differentiation between the Yaounde and Mbalmayo schists; despite the reflectance anomalies evidenced NW of Akonolinga, hydrothermal alterations in the study area failed to be detected. Besides, aeromagnetics depicted a moderately fractured northern zone (the CAFB) contrasting with a high densely fractured zone (the CC, known as Ntem complex). The Ntem complex displays signatures of a meta-
igneous, an intrusive complex, greenstone relics south of Sangmelima and hydrothermal activity. Indeed, CET porphyry analysis tool detected many porphyry centres. In general, the study revealed many lineaments including contacts, fractures faults zones and strike-slips. The major aeromagnetics structures are SW-NE to WSW-ENE and WNW-ESE to NW-SE while those from Landsat-8 are NE-SW, WNW-ESE, NW-SE, WSW-ENE and NW-ESE to NNW-SSE. Together, these structures depict trans-compressions or trans-tensions corresponding to a broad NE-SW strike-slips channel that affect both the CAFB and the Ntem Complex, and they control the intrusions thus confirming a pervasive hydrothermal activity within the Ntem Complex. The proximity or coincidence of these porphyry centres with some mapped Iron-Gold affiliated mineral indices and porphyry granites indicate the possible occurrence of many hydrothermal ore deposits. These results show the high probability for the Ntem complex to host porphyry deposits so they may serve to boost mineral exploration in the Yaounde-Sangmelima region and in the entire southern Cameroon as well.
