Assessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area.

Assessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area. | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Assessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area. Jean Daniel Ngoh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4624656/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In this study, aeromagnetic data were used to construct a geological model of the Guider-Kaele area in northwestern Cameroon, which is part of the northern segment of the Pan-African belt in Cameroon. The area is dominated by the Poli and Mangbei lithostratigraphic Groups (Neoproterozoic metasedimentary rocks and metavolcanic rocks) intruded by late Pan-African granitoids and tertiary ring complexes. For quantitative analysis, 2.75D forward modelling of these magnetic data was performed using Oasis Montaj v. 8.4 along four transects oriented N‒S (two lines), NNE‒SSW and NNW‒SSE.. Well log information, borehole data, geologic maps, previous geophysical studies, and Euler deconvolution depth estimates constrained the models derived. In particular, Euler’s deconvolution estimated the depth to the magnetic sources (faults and some intrusions) in the 0.39 km to 11.44 km range beneath sea level. Furthermore, the proposed geological models highlight a subsurface composed of a volcanic-sedimentary cover overlying a granitic faulted basement, with some igneous intrusions (doleritic dyke swarms and granodiorites) and several troughs filled with volcanic-sedimentary deposits. In addition, these models reveal that the crust is thinning. The presence of a prominent greenschist layer in this area testifies to the thermal history or degree of metamorphism of its bedrock. Geophysics Planetary Science 2.75D forward modelling Pan African Belt volcano-sedimentary layer thermal history crustal thinning. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1. Introduction To date, several geological and geophysical studies have been carried out on the Pan-African Belt in Central Africa (Nguimbous et al., 2010, Abate Essi et al., 2017 , and references therein), with a particular interest in the mapping of crustal formations and their evolution. Certainly, the contributions of these works have led to major modifications concerning the lithostratigraphy and geodynamic evolution of this geological complex. However, despite previous works and the exploitation and mining of marble in the study area, northern Cameroon remains a relatively poorly known and underexplored region. In fact, the Congo Craton-Adamawa-Yade boundary captured almost all the attention of previous works concerning the Pan African belt in Cameroon. Previous studies revealed that this area, because of its pivotal position between the East-Nigeria area in the west, belonging to the Trans-Saharan chain (Ferré et al., 1998 , 2002 ), and the Mayo-Kebbi domain with juvenile crust to the East (Penaye et al., 2006 ; Isseini, 2011 ), and the Adamaoua-Yadé domain, delimited by the Tcholliré-Banyo Fault (Toteu et al., 2004 ) to the south, would have been intensely affected by successive tectonic events of the Pan-African orogeny. As a result, the bedrock characterization in this area is poorly understood and poses problems related to i) the lithostratigraphy; ii) the nature of the contacts (intrusive, sedimentary, tectonic, metamorphic gradient) between the different sets; and iii) tectonic and geodynamic evolution and the implications for mineral resources. The aim of this work is to examine the metamorphic conditions through 2.75D geophysical modelling of aeromagnetic data in the Guider-Kaele area, northern Cameroon. 2. Geological and tectonic setting The Guider-Kaele area, which belongs to the Pan African domain in Cameroon, ranges between 09°45' and 10°45’N and 13°15' and 14°30’E. In this area, a soudano-Sahelian climate prevails. The average temperature is between 24°C and 36°C. As a part of the northern domain of the Central African Orogeny Belt (CAOB) in Cameroon, especially the Poli-Lere Group, the study domain consists of medium- to high-grade schists and gneisses of volcanic and sedimentary origin that formed in a magmatic back-arc context (Toteu et al., 2006 ) and Neoproterozoic syntectonic calc-alkaline granitoids (Penaye et al., 2006 ). The post-Pan African tectonic calc-alkaline granitoids comprise mafic and felsic dykes crosscutting granites and syenite intrusions in schists and gneisses. They align along a NNW-trending line between batholiths (Toteu et al., 2006 ). The above units are covered by unmetamorphosed sediments and volcanic rocks in several small basins (Toteu et al., 2004 ; Van-Schmus et al., 2008 ). The Palaeoproterozoic formations and Pan-African batholiths of the Adamawa-Yade domain (Houketchang et al., 2009) (Fig. 1 ) dominate the far southeast of the study area. Three tectonic events affected the structural development of this domain, notably a crustal shortening and thickening event caused by collision between Neoproterozoic blocks followed by syn- to postorogenic shear movements (Toteu et al., 2004 ; Ngako et al., 2008 ). A crustal shortening event is shown by gentle folding in isoclinal folds with flat-lying foliations formed by thrust faulting (Fig. 1 ) (Ngako et al., 2008 ). Later, compressional deformation is indicated by vertical and NNE-trending foliations and by tight upright to reclining folds (Ngako and Njonfang, 2011 ). In the Poli area, this deformation is accompanied by dextral and sinistral shearing (Dawai et al., 2013). 3. Aeromagnetic data acquisition and processing The aeromagnetic data used in this study were acquired from the Africa Magnetic Mapping Project (AMMP) surveys of PGW Ltd. (Paterson, Grant & Watson Limited) in collaboration with GETECH and ITC. The flight path was flown at 235 m above the topographic level with a line spacing of 750 m along the N135°E azimuth. Each individual survey was corrected for diurnal variations and gridded using a standard minimum curvature into one coherent dataset. Then, the regional magnetic field of the Earth or the International Geomagnetic Reference Field (IGRF) was removed from the signal to produce a residual magnetic field (TMI), which was gridded at 1/5 of the flight line spacing and displayed as a colour image. Then, the TMI grid was reduced to the equator (RTE) using the inclination and declination angles of the IGRF (-1.01° and − 3.96°, respectively). The RTE anomaly map (Fig. 2 ) contains both small wavelength anomalies, high-intensity anomalies created by magnetized sources at the surface or at shallow depths, and longer wavelength anomalies related to deeper sources. To amplify the effect of the deeper sources, the RTE data were collected upwards to a height of 1 km above the Earth’s surface. 4. Methodology 4.1. The Euler deconvolution method Euler deconvolution (ED) is an analytical method based on Euler's homogeneity equation (Thompson, 1982 ; Reid et al., 1990 ) that is used to estimate the apparent locations and depths of several subsurface features, particularly from magnetic or gravitational fields. The degree of homogeneity is expressed by the structural index, which measures the fall-off rate of the field with distance from the source, as shown by the following equation from Thompson ( 1982 ) and Reid et al. ( 1990 ): For magnetic data, N takes values from 0 to 3 (Thompson, 1982 ; Reid et al., 1990 ). Reid et al. ( 1990 ) showed that only low structural indices (0 to 1) provide the best depth estimates. The Euler depths appear wherever there are lithological discontinuities in the geological formations. They represent the structural and/or stratigraphic changes in various geological formations (Owona-Angue et al., 2013). 4.2. Magnetic modelling For the present study, forward modelling of the source body was performed with the GM-SYS module in Oasis Montaj v8.4 to obtain the optimal fit of the generated source model to the magnetic data. The GM-SYS module helps to calculate the magnetic response from a geological cross-section model. The methods used to calculate the model’s response are based on the methods of Talwani et al. ( 1959 ) and Talwani and Heirtzler ( 1964 ), as well as the algorithms described by Won and Bevis ( 1987 ). Two-and-a-half-dimensional calculations are based on Rasmussen and Pedersen ( 1979 ). The GM-SYS inversion routine utilizes a Marquardt inversion algorithm (Marquardt, 1963 ) and the USGS computer program SAKI (Webring, 1985 ) to linearize and invert the calculations. 5. Results 5.1. Analysis of total magnetic anomaly intensity reduced to the equator (RTE) The RTE magnetic map (Fig. 2 ) reveals anomaly values between − 77 and 300 nT, corresponding to magnetic anomalies covering a wide range of amplitudes and wavelengths. A correlation between the anomalies and some morphological features, such as faults, geological contacts and outcrops, can be inferred. Within northwestern Cameroon, these magnetic anomalies seemingly correlate with Proterozoic granitic and metamorphic lithologies, including metavolcanic rocks, gneisses, and schists (Fig. 1 ). The RTE map contains mainly northeast-trending minima and maxima anomalies that are roughly parallel to the Proterozoic synorogenic strike-slip episodes (Ngako et al., 2008 ). The most prominent anomalies are a series of large wavelengths, low-amplitude magnetic maxima (anomalies 1 and 2) and slightly greater magnetic-amplitude minima (anomalies 3 and 4) in the northern portion of the map (Fig. 2 ). The magnetic maxima are caused by lithologies with lower magnetic susceptibility. Anomalies 1 and 2 occur over the medium- to high-grade gneisses of the NW Cameroon terrane and post-Pan African sediments. In contrast, anomalies 3 and 4 occur over metamorphic Precambrian substrata (ectinites and migmatites) overlain by sedimentary formations (Regnoult, 1986 ) (Fig. 1 ). The extent of these low-amplitude magnetic maxima implies that the magnetic susceptibility of the gneisses is relatively low, with some regions (small wavelength maxima within the region of anomaly 1) having higher susceptibility values. This could be due to high-grade gneisses or isolated mafic or metaigneous bodies (Ngoh et al., 2020 ). In fact, in the study area, the level of weathering of rocks is highly variable. For example, the outcrops encountered and observed in situ show folded, faulted and fractured rocks with some weathering facts available on the ground surface. This weathering impacts the petrographic and geochemical characteristics of rocks and thus the magnetic susceptibility of these rocks. The upwards continued RTE map (Fig. 3 ) exhibits similar patterns of high and low magnetic anomalies, as shown in Fig. 2 . The upwards continued RTE anomaly ranged from − 164.47 to 288.31 nT. The upwards continued RTE map is basically a smoothed version of the RTE map and contains prominent negative (long wavelength) anomalies distributed in the northeastern, central, and southern parts of the study area. This map clearly highlights positive and negative prominent anomalies roughly elongated in the ENE‒WSW direction. The persistence of prominent anomalies with great wavelengths, low-amplitude magnetic maxima (anomalies 1 and 2) and slightly greater-amplitude magnetic minima (anomalies 3 and 4) observed in the northern portion of the map (Fig. 3 ) shows that they are associated with deeper structures. In addition, the upwards continued RTE map shows attenuated anomalies (anomalies 8, 9 and 10) that are also related to upper crustal lithologies. The distribution of these different patterns clearly suggests that the study area is characterized by zones of high and low magnetic susceptibility within different lithologies at depth. Microfaults and microfolds observed in the field were more developed and prevalent within some metamorphic rocks. The structures have various strikes (NE‒SW, NNE‒SSW and E‒W) and subvertical dips, in accordance with the regional structures controlling them. These faults could have been caused by vertical movements due to subsidence of the basin and lateral movements due to shearing and could have affected the substratum (Cimencam, 2016 ). Mapping observations revealed that there was more than one deformation phase. The geodynamic environment corresponds to a sedimentary basin (Mayo Oulo-Lere basin) put in place during the initiation of the South Atlantic opening (Regnoult, 1986 ). 5.2. Depth estimates The Euler deconvolution technique is an analytical method chosen for detecting the locations and depths of different features from obtained anomalies. This study focuses on geological boundaries, faults and dyke locations. The structural indices used are 0.25 and 1.25, corresponding to ideal geometrical contacts and faults, respectively (Barbosa et al., 1999 ). Euler deconvolution is applied to the magnetic RTE field with a 20 km x 20 km window size in the Oasis Montaj Program v.8.4, which provides better resolution for the solutions. The obtained Euler’s solution maps are shown in Fig. 4 . a and Fig. 4 . b . These solutions are relatively consistent with short- and long-wavelength anomalies related to different tectonic features and some lithological formations in the study area. The depths of the faults and contacts ranged from 0.39 km to 11.44 km in the NNW‒SSE, NE‒SW, NW‒SE, and E‒W directions. 5.2.1. Euler solutions for structural index SI = 0.25 The solutions for a structural index of 0.25 (Fig. 4 . a) are located between 0.39 km and 6.6 km depth, with an average depth of 2.32 km. These solutions are more clustered and mainly follow the NW‒SE, NE‒SW and E‒W directions. Most of these solutions represent deep-seated structural features. The surface features and resulting lineaments are located above 0.39 km in depth. The moderately deep-seated solutions are in the central, eastern and southwestern parts of the study area, while the depth solutions of other parts of the area are relatively shallow under an average depth, thus inferring shallow magnetic anomaly sources. In accordance with the geodynamic model proposed by Toteu et al. ( 2004 ), the configuration observed in the area suggests the presence of two collisional blocks: the southern block with a passive and older margin and the northern block with an active margin. This collision generated intense deformation in the North Cameroon domain due to the penetration of the rigid block into the active margin (Abdelsalam et al., 2002 ). 5.2.2. Euler solutions for structural index SI = 1.25 The Euler solutions for the structural index of 1.25 (Fig. 4 . b) provide a depth range from 0.76 km to 11.44 km. As shown previously, there are more similarities and clusters of solutions with solutions for a structural index of 0.25. The observed abundance of solutions in the study area implies the existence of a broad set of dykes or vertical faults. These clusters are crosscut by those due to deep magnetic sources (≥ 5 km) oriented NE‒SW, which have linear stacks of solutions predominant in the NE‒SW, NNW‒SSE, E‒W and NW‒SE directions. There is a lack of solutions in the northern, western, eastern, and southern margins of the study area. The patterns of Euler depths (Fig. 5 . a and Fig. 5 . b ) obtained by interpolation of each structural index are similar and show that the bedrock of the study area is strongly affected by intermediate and deep tectonic features (≥ 3 km), which seem not to exceed a depth of 7 km. The values obtained are within the range of those obtained by previous researchers in the area. There is also a concentration of deep magnetic sources mainly along the NE‒SW to ENE‒WSW directions. This zone is particularly a large-scale apparent average depth zone oriented along the Mousgoy-Moutouroua axis, which would have imposed these preferential directions in both cases. This axis, which contains a set of granitoids and orthogneisses, would therefore be dominated by the structural imprint of the metagongroses of the Mayo-Kebbi domain. Some previously known lineaments and features in the area are highlighted through a clustering of solutions that coincide with their directions. Then, a general trend in the zone of weakness can be observed and linked to the regional tectonic features encountered in the study area. According to both Euler maps, the northeastern area has no more solutions, which implies extremely weak tectonics in that zone. The deepest geological features are located below 5 km; they follow the NNE–SSW, E‒W and NNW‒SSE directions and dominate the study area. 5.3. Magnetic modelling In general, the shape of an anomaly can help to determine the shape and position of density or magnetic contrasts. Theoretically, several geometries will fit a particular anomaly. However, in practice, using realistic geological or other geophysical controls, anomaly fits provide real numerical constraints on anomaly sources (Prieto & Pratsch, 2000 ). Furthermore, the shape and amplitude of the magnetic response depend on many other variables in addition to the concentration of magnetic minerals present, which include the geometry and depth of the deposit, its orientation relative to the magnetic field to the north and the inclination of the Earth’s magnetic field at its location (Prieto & Pratsch, 2000 ; Okiwelu et al., 2011 ). In this study, four geological cross sections were modelled from the RTE map (Fig. 6 ) with a 2.75D forward modelling approach in GM-SYS. These models were constrained by geological knowledge, borehole data (Cimencam, 2016 ) with a maximum depth of 69 m and Euler depths of the study area, and models with a root mean square (RMS) less than 5% were accepted. 5.3.1. Profile 1 The magnetic north‒south cross-section P1 is situated near the Mindif-Kaele axis and is approximately 56 km long. Along this transect, the magnetic field anomaly intensity oscillates between − 255.42 nT and 363 nT (Fig. 7 ). This is possibly caused by subsurface discontinuities or major formations. The magnetic field decreases to -255.42 nT at approximately 11.4 km, while it peaks at 363 nT at approximately 19.3 km from the north. This variability in the magnetic field intensity along the transect reflects the heterogeneity of the Earth's crust. The modelled geological section highlights a subsurface sequence formed by a sedimentary cover including detrital sediments, lagoon-lacustrine sandstones, or arkose-sandstones with a magnetic susceptibility of 0.0209 SI. The latter are bottomed by schists (with a magnetic susceptibility of 0.003 SI), which overlie a crystalline, tabular, and faulted basement. The whole basement consists of gneissic and granitic formations (syn-tectonic granites) with susceptibilities of 0.025 SI and 0.05 SI, respectively. This geological model also highlights a prominent intrusion or batholith overlain by sedimentary formations that extend down beyond 10 km depth into the crystalline basement. The magnetic susceptibility (0.051 SI) of this intrusive batholith suggested that it could be a granodiorite or syenogranite, which are members of the granitoid group. In addition to the observed batholith, this model also reveals a strongly faulted crystalline basement that allowed small magmatic intrusions or magmatic lift during metamorphism. The progressive uplift of the crystalline basement formations from north to south suggests a zone of surrection, the consequence of which would be the rise of the granito-gneissic or granito-migmatitic basement, which would result from the Pan-African orogeny. In addition, given the stratigraphy and apparent geometry of the basement, this geological model reveals a sedimentary basin with crystalline bedrock, which, according to Bessoles and Trompette (1980), constitutes the envelope form and emphasizes the synclinal termination of the Maroua volcano-detrital vein. 5.3.2. Profile 2 Magnetic profile P2 is also north‒south, measures approximately 84 km in length, and cuts the study area longitudinally along the Guider-Figuil axis. Along this transect, the observed magnetic field anomaly varies from − 67.9 to 210 nT. The profile is irregular, and the occurrence of many peaks indicates the presence of discontinuities or geological features (Fig. 8 ). The fairly high magnetic signal in contrast to that in the first profile is a probable signature of near-surface high magnetic susceptibility formations. Like in transect P1, the geological model is a three-layered subsurface. The sedimentary cover (k = 0.0209 SI) consists of limestone, conglomeratic arkosic and ferruginous sandstone layers; then, a schist layer (k = 0.003 SI) is bottomed by a basement made up of gneisses (k = 0.025 SI) and granites (k = 0.05 SI). In addition, this geological model highlights intense fracturing of the crystalline substratum, whose northern block seems to have collapsed while the southern block has moved up. This apparent configuration suggests the existence of multiple faults with vertical displacement and justifies the presence of a crystalline basement uplift observed along this cross section. Therefore, the model’s general architecture suggests that regional metamorphism heavily affected the local basement. This general architecture and the lithology derived from the model therefore highlight that the combined effects of intense tectonic activity and regional metamorphism heavily affected the basement of this area. 5.3.3. Profile 3 The magnetic cross-section P3 is approximately 33 km in length in the NE‒SW direction and is located in the Bossoum-Dourbeye surroundings. Along this transect, the intensity of the magnetic field anomaly oscillates between − 55 and 155 nT. The 2.75D modelled subsurface sequence shows a downwards sedimentary cover lying on top of the schists, and these two geological formations (sedimentary cover and schists) overlie a crystalline faulted basement, which consists of gneisses and granites. The model also highlights a dolerite (k = 0.062 SI) rooted in the gneisses, which would have been emplaced during the syn-orogenic reactivation phases. Therefore, this hypabyssal intrusion resulted from swarms of dikes emanating from a large intrusive body at depth and was facilitated by fracturing of the gneissic formations or lithostratigraphic contact. 5.3.4. Profile 4 Magnetic profile P4 extends more than approximately 10.40 km in the NW‒SE direction and intersects profile P3. Herein, the magnetic field intensity ranges between − 60 nT and 160 nT, with only two peaks, which could be due to the presence of an important geological structure or formation. The geological model (Fig. 10 ) almost conforms with the previous models despite some differences in the shape and amplitude of the anomaly. From northwest to southeast, there is a relative rise (thickening) of the granitic bedrock and thus a thinning of the sedimentary cover, probably resulting from regional isostatic compensation. Like the previous model, this model also suggests the presence of a synform or syncline with a granitic-gneissic basement filled by schist formations. Fracturing with granitic basement infiltration occurs near the northern flank. The southern flank of this syncline was subjected to major fracturing of the granitic bedrock, which was filled by the schist layer. These subsurface faults, fractures, or parts of the geological layers could test the extent and impacts of the tectonic events that occurred during the Pan African orogeny. In addition, the modelled crystalline basement sometimes collapsed or rose and was dotted with subbasins of the sedimentary layer. From northwest to southeast, the geomorphology of this granitic basement suggests an uplifted zone, which results from isostatic compensation, and the presence of a probable granitic unconformity or schistogneissic layer affected by an extensional trough. The thickness of the schist layer, which results from the metamorphism of sedimentary formations with carbon or clayey materials, indicates the extent of the sinking of this synform or syncline. 6. DISCUSSION The Euler deconvolution solution map highlights more clustered solutions from south to north of the study area. Generally, the Euler solutions for different structural indices show a depth range of 0.39 km to 11.44 km (Fig. 4 a and Fig. 4 b). The greatest depth of geological features is found in the central part of the study area and is relatively scattered around the southwestern edge. The basement rocks in the northwest and southeast regions are relatively shallow. These clustered solutions highlighted several main E‒W, NE‒SW and NW‒SE trends, which fit the regional trends. With regard to the major directions, spatial distributions, and roof depths of the investigated structures obtained by the application of Euler’s deconvolution method, these geological formations would indeed be deep-seated. The structural trends highlighted suggest that the main NE geological feature is the tectonic imprint of the Katanguian orogeny, which controls the tectonic arrangement of the Pan-African domain and was confirmed by the Massenya-Ounianga heavy gravity anomaly line (Poudjom-Djomani et al., 1995 , Abate Essi et al., 2017 ). In addition, according to some authors (Poudjom-Djomani et al., 1995 ; Loule et al., 2009; Ganno et al., 2010 ), this dominant structural trend could also be due to the opening of the South Atlantic Ocean, for which the direct insight was the collapse of the unstable corridor of northern Cameroon and southern Chad, with a main NNE‒SSW structural trend (Cornachia & Dars, 1983). Thus, this configuration suggests the earlier hypothesis for global NE‒SW geological and tectonic features. The geological models obtained through 2.75D modelling highlight a mainly faulted geological environment. These geological models revealed sedimentary, metamorphic, and igneous formations overlying a syntectonic granitic basement. The presence of strongly foliated metamorphic rocks such as schists and gneisses in this area suggests that this region could either have been affected by regional metamorphism or originated from deformation under differential stress conditions resulting from tectonic forces, as witnessed by the several metamorphosed rocks occurring in the eroded mountain chain (e.g., as seen in Mindif surroundings) (Stephen, 2018 ). The hypothesis of regional metamorphism seems to be confirmed by the presence of a thick schist layer in the four subsurface 2.75D models. In addition, according to previous geophysical works and geological information (Poudjom et al., 1993 & 1995; Kamguia et al., 2005 ; Nguimbous et al., 2010), with regard to the geometry, thickness, and spatial disposition of layers, the dominant metamorphic facies in the area under study result from high-temperature and high-pressure geothermal gradients. These geological models also highlighted faulting and a southwards progressive thickening of the crust. This occurs because the crust in that area sinks farther either to compensate for the added weight or to react to compressional stresses in the rocks due to tectonic forces. The upwelling or crustal thinning zones, considering the hypothesis of an isostatic phenomenon, could be due to a shallow or deep prominent magmatic source. Several authors (Kamguia et al., 2005 ; Nguimbous et al., 2010) have linked this configuration to the tectonic accidents affecting this region. For example, those affecting Central Cameroon with the establishment of horsts represented by the Adamawa granites or an E‒W extension phase prevailed on the Cameroon Volcanic Line (Popoff et al., 1983 , Reusch et al., 2010 ). Therefore, the several probable subbasins observed in these modelled transects could result from the manifestations of regional isostatic compensation following the elevation of the Adamawa horst, which is in isostatic equilibrium at altitudes below 1000 m (Poudjom et al., 1993). In addition, since the Pan-African belt, in which the study area is located, underwent various tectonic events marked by several rifting phases characterized by prerift deformation followed by crustal thinning. Accordingly, with Poudjom et al. (1995), the idea of crustal thinning on a regional scale seems more plausible. Furthermore, the modelled sections revealed several high magnetic signatures interpreted as intrusions with different susceptibility values. These intrusions vary from one profile to another and suggest potential mineralization zones in this region. Their presence could result from the upwelling of igneous material in the area, probably through diapiric activity, which is a sliding regime leading to the segregation of granodioritic magma (Pons et al., 1995 ). In fact, the green schist facies encountered in the field results from thermal changes leading to the transformation of clays (shale) and limestone into schists and marble, respectively, reaching the green schist facies. This modified the original stratification of the layers observed in the field, giving them a subvertical dip. This hypothesis could explain the presence of high magnetic susceptibility (k = 0.051 SI) granodiorites observed in profile P1 near Mindiff and another high susceptibility intrusion (k = 0.062 SI) in profile P3. In addition to syntectonic plutonism resulting in occasional erosion of orthogneisses, this area records Pan-African late- and postorogenic intrusive rocks such as Mindiff syenite or granodioritic rocks. The evidence of these various intrusive bodies is facilitated by a densely fractured basement, which allows upwelling of mantle materials leading to several batholiths or dikes, swarms all emanating from a large intrusive body at depth. These faults likely weaken the crust in various areas; if they are not filled by crustal material, they are filled by sedimentary or volcano-sedimentary formations. 7. Conclusion In this region, magnetic modelling of the four profiles improved on the reduced-to-equator anomaly map. The reduced to equator anomalies (RTE) map displays magnetic anomalies covering a wide range of amplitudes and wavelengths, with a relatively good correlation between the anomalies and some morphological features, as observed in northwestern Cameroon. The reduced to equator anomalies (RTE) map presents mainly northeast-trending minima and maxima anomalies that are roughly parallel to the strike-slip tectonic episodes. Euler’s deconvolution highlights more clustered solutions from south to north characterized by depth values ranging from 0.39 km to 11.44 km. These clustered solutions highlighted several main E‒W, NE‒SW and NW‒SE trends, which fit the regional trends. The 2.75D forward models obtained highlight faulted and folded geological facies characterized by the presence of several metamorphic rocks. This study suggested that the area was affected by many tectonic features during the Pan African orogeny. Several unconformities materialized by folded and faulted basement or synclinal troughs separated by anticlinal ridges have been highlighted. Declarations Data availability The data used to support the findings of this study are available from the corresponding author upon request. Conflict of interest The authors declare that there are no conflicts of interest regarding the publication of this paper. Acknowledgements The authors are grateful to the reviewers for their constructive comments. 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Lithos, 45, pp. 255-279. Ganno, S., Nzenti, J.P., Ngnotue, T., Kankeu, B. and Kouankap, N.G.D., 2010. Polyphase deformation and evidence for transpressive tectonics in the Kimbi area, Northwestern Cameroon Pan-African fold belt. Journal of Geology and Mining Research. Vol. 2(1), pp. 001-015. Isseini, I., 2011. Croissance et différenciation crustales au Néoprotérozoïque : exemple du domaine panafricain du Mayo-Kebbi au Sud-Ouest du Tchad. Thèse de Doctorat Université Henri Poincaré, Nancy, France, 339 p. Kamguia, J., E. Manguelle-Dicoum, C. T. Tabod and J. M. Tadjou, 2005. Geological models deduced from gravity data in the Garoua basin, Cameroon. Journal of Geophysics & Engineering, 2, pp.147-152. Loule, J.P. and Lumbomil, P., 2009. The Logone Birni Basin (LLB) in Northern Cameroon: Transition between the West African Rift Sub-System (WAS) and the Central African Rift Sub-System (CAS); Tectonic and Geophysical Models. Search and Discovery Article #50171. Marquardt, D.W., 1963, an algorithm for least-squares estimation of nonlinear parameters, J. SIAM, 11, pp. 431-441. Ngako, V., Affaton, P., Njonfang E., 2008. Pan-African tectonics in northwestern Cameroon implication for the history of western Gondwana. Gondwana Research, 14, pp. 509-522. Ngako, V., Njonfang, E., 2011. Plates amalgamation and plate destruction, the Western Gondwana history. In: D. Closson (Ed.), Tectonics. INTECH, UK, p. 3-34. Ngoh, J. , Mbarga, T. , Mickus, K. , Tarek, Y. and Tabod, T.. 2020. Estimation of Curie Point Depth accross the Pan African belt in Northern Cameroon from aeromagnetic data. Open Journal of Earthquake Research, 9, 217-239 Nguimbous-Kouoh, J.J., Ndougsa-Mbarga, T., Njandjock-Nouck, P., Eyike, A., Campos-Enriquez, J.O., Manguelle-Dicoum, E., 2010. The structure of the Goulfey-Tourba sedimentary basin (Chad-Cameroon): a gravity study. Geofisica Internacional, 49 (4), pp. 181-193. Okiwelu, A. A., Okwueze, E. E., OBI, D. A., 2011. Specific Issues on Gravimetric and Magnetic Methods of Geophysical Exploration. European Journal of Scientific Research, 48(3), pp.399-423. Owona Angue, M.L.C., Tabod, C.T., Nguiya, S., Kenfack, J.V. and Tokam Kamga, A.P., 2013. Delineation of Lineaments in South Cameroon (Central Africa) Using Gravity Data. Open Journal of Geology, 3, pp. 331-339. Penaye J., Kröner A., Toteu S.F., Van Schmus W.R., Doumnang J.C., 2006. Evolution of the Mayo Kébbi region as revealed by zircon dating: an early (ca. 740 Ma) Pan-African magmatic arc in southwestern Chad. Journal of African Earth Sciences, 44, pp. 530-542. Pons, J., Barbey, P., Dupuis, D., & Léger, J. M., 1995. Mechanisms of pluton emplacement and structural evolution of a 2.1 Ga juvenile continental crust: The Birimian of southwestern Niger. Precambrian Research, 70(3-4), pp. 281-301. Popoff, M., Benkhelil, J., Simon, B., Motte, J.J., 1983. Approche géodynamique du fossé de la Bénoué (NE Nigéria) à partir des données de terrain et de télédétection. Bull. Centre Rech. Explo. Prod Elf Aquitaine, 7. (1), pp. 323-337. Poudjom-Djomani, Y. H., Nnange, J. M., Diament, M., Ebinger, C. J. and Fairhead, J.D., 1995. Effective elastic thickness and crustal thickness variations in West Central Africa inferred from gravity data. Journal of Geophysical Research, vol. 100, pp. 22047-22070. Poudjom-Djomani, Y.H., 1993. Apport de la gravimétrie à l’étude de la lithosphere continentale et implications géodynamiques: étude d’un bombement intaplaque: le massif de l’Adamaoua (Cameroun). Thèse de Doctorat, Université de Paris Sud, Centre d’Orsay, 294 p. Prieto, C., and Pratsch, C., 2000. Gulf of Mexico study links deep basement structures to oil fields: Demonstrating deep structural control. Integrated Geophysics Corporation footnote series, 4 p. Rasmussen, R., Pedersen, L.B., 1979. End corrections in potential field modelling, Geophysical Prospecting, 27, pp.749-760. Regnoult, J. M., 1986. Synthèse géologique du Cameroun, s.l.: Ministère des mines et de l'énergie (Rép. Cameroun). Reid A.B., Allsop J.M., Granser H., Millett A.J. & Somerton I.W., 1990. Magnetic interpretation in the three dimensions using Euler deconvolution. Geophysics, 55, pp. 80-91. Reusch, A., Nyblade, A., Wiens, D., Shore, P., Ateba, B., Tabod, C., Nnange, J., 2010. Upper mantle structure beneath Cameroon from body wave tomography and the origin of the Cameroon Volcanic Line. Geochem., Geophys., Geosyst., 11 (10), pp. 1-17. Doi: 10.1029/2010GC003200. Stephen, A., N., 2018. Petrology, lectures notes. 14p Talwani, M., Heirtzler, J. R., 1964. Computation of magnetic anomalies caused by two 451 dimensional structures of arbitrary shape. Computers in the mineral industries, part 452 1: Stanford University publications, Geol. Sciences 9, pp. 464-480. Talwani, M., Worzel, J., Landisman, M., 1959, Rapid gravity computations for two-dimensional bodies with apllication to the Mendocino submarine fracture zone, J. Geophys. Res., 64, pp. 49-59. Thompson, D. 1982. EULDPH: A new technique for making computer-assisted depth estimates from magnetic data. Geophysics, 47 (1), pp. 31-37. Toteu, S.F., Penaye, J., Djomani, Y.P., 2004. Geodynamic evolution of the Pan-African belt in central Africa with special reference to Cameroon. Canadian Journal of Earth Sciences 41, pp. 73–85. Toteu, S.F., Penaye, J., Deloule, E., Van Schmus, W.R., Tchameni, R., 2006. Diachronous evolution of volcano-sedimentary basins north of the Congo craton: Insights from U–Pb ion microprobe dating of zircons from the Poli, Lom and Yaoundé Groups (Cameroon). Journal of African Earth Sciences, 44, pp. 428–442. Van Schmus, W.R., Oliveira, E.P., Da Silva Filho, A.F., Toteu, S.F., Penaye, J., Guimarães, I.P., 2008. Proterozoic links between the Borborema Province, NE Brazil, and the Central African Fold Belt. In: Pankhurst, R.J., Trouw, R.A.J., de Brito Neves, B.B., De Wit, M.J. eds., West Gondwana. Pre-Cenozoic correlations across the South Atlantic region. Geological Society (London), Special Publication 294, pp. 69-99. Webring, M., 1985. Semiautomatic Marquardt inversion of gravity and magnetic profiles. U.S. Geological Survey Openfile Report OF-122. 110 p. doi: 10.3133/ofr85122 Won, I.J. and Bevis, M., 1987. Computing the Gravitational Magnetic Anomalies Due to a Polygon: Algorithm and FORTRAN Subroutines. Geophysics, 52, pp. 232-238. Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4624656","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":317855298,"identity":"bc481851-f5fd-449e-8194-6176920bcbac","order_by":0,"name":"Jean Daniel Ngoh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuklEQVRIiWNgGAWjYBACxoYEEGEDYjYeIEVLGphJnBYGBrCWw2AmcVqY23MPv/i447zd2vbDQFtqbKIJO6znXZrlzDO3k7edSQRqOZaW20BQy4wcM2PettvJZgeAWoAuJFrLuWSz8w+J12L8mLftgJ3ZDaJt6XljxjizLTnB7AbQlgRi/GLYnmP84WObnb3Z+fSHDz7U2BChpYGBTQJIJ4JVJhBSDgLywKj5AKTtiVE8CkbBKBgFIxQAADopS53EU4+aAAAAAElFTkSuQmCC","orcid":"","institution":"national advanced school of public works","correspondingAuthor":true,"prefix":"","firstName":"Jean","middleName":"Daniel","lastName":"Ngoh","suffix":""}],"badges":[],"createdAt":"2024-06-23 09:33:06","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-4624656/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4624656/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":59016974,"identity":"59b9e2fc-e2e1-4201-9c48-93f87070233e","added_by":"auto","created_at":"2024-06-25 10:44:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":454683,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSimplified geologic map of the study area (Penaye et al., 2006, modified as a document available in a public domain): \u003c/strong\u003e(1) post-Pan-African sediments; (2) late to posttectonic Pan-African granitoids; (3) syntectonic granites; (4) Mayo-Kebbi batholith: tonalites, trondhjemites and granodiorites; (5) medium- to high-grade gneisses of the NW-Cameroon domain; (6) mafic to intermediate complex of the Mayo-Kebbi domain (metadiorites and gabbro diorites) and amphibolites; (7) Neoproterozoic low- to medium-grade volcano-sedimentary sequences of the Poli-Léré Group; (8) remobilized Palaeoproterozoic Adamawa-Yadé domain; (9) thrust front; (10) strike-slip fault: TBSZ= Tcholliré-Banyo shear zone; GGSZ= Godé-Gormaya shear zone; BSZ= Balche shear zone; (11) state border.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/fbc4bf55ca476c9c6105e73f.png"},{"id":59016205,"identity":"e5ac183c-470d-4a34-a92a-c2679d95c589","added_by":"auto","created_at":"2024-06-25 10:36:01","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":494140,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTotal magnetic anomaly intensity reduction to the equator map of the study area\u003c/strong\u003e.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/ce09f088347954911990b473.png"},{"id":59016203,"identity":"f46dc767-1ad4-437d-a61d-0b4fad4d22b6","added_by":"auto","created_at":"2024-06-25 10:36:01","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":200226,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRTE map (Fig. 2) upwards continued to 1 km above the Earth’s surface\u003c/strong\u003e.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/cb84bd8ba21ebfb288c21809.png"},{"id":59016975,"identity":"e3effe1c-d0da-4280-9971-7a3cb60b4564","added_by":"auto","created_at":"2024-06-25 10:44:01","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":699450,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea: Euler solutions for SI=0.25\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eb: Euler solutions for SI=1.25\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/b1e8667afb83ac31212d6084.png"},{"id":59016978,"identity":"397d5931-67f9-47a3-9187-24b6d874558f","added_by":"auto","created_at":"2024-06-25 10:44:01","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":623276,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea: Euler depth map of the study area for SI=0.25\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eb: Euler depth map of the study area for SI=1.25\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/96c5e087df6d5fb3cfea9fd8.png"},{"id":59016976,"identity":"b696b6bc-98e6-4a5c-8d14-af395c38e409","added_by":"auto","created_at":"2024-06-25 10:44:01","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":765279,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTotal magnetic anomaly intensity reduction to the equator map of the study area with the locations of different profiles\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/cb57e069c2f877e1bf6e6574.png"},{"id":59016208,"identity":"578361fe-c29d-4a42-96b7-3ed7771be264","added_by":"auto","created_at":"2024-06-25 10:36:01","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":295775,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModel of Profile 1\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/ef6db8333bb8944102112269.png"},{"id":59017528,"identity":"08434d7e-6c25-4d41-86cb-2a54a1a169ab","added_by":"auto","created_at":"2024-06-25 10:52:01","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":236812,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModel of Profile 2\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/aae8cf1aa8f7d1a2e245cf73.png"},{"id":59016209,"identity":"b0f46274-b6ad-4639-9867-4a202c906766","added_by":"auto","created_at":"2024-06-25 10:36:01","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":284082,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModel of Profile 3\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/a0387ebe7e023f28a4f7c0a1.png"},{"id":59016213,"identity":"a5104d94-70b3-4e24-93ef-527eea413629","added_by":"auto","created_at":"2024-06-25 10:36:01","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":325808,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModel of Profile 4\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/da07f28ac317f069c44f7be1.png"},{"id":59017936,"identity":"54a89a85-84c3-4b0c-b862-2bdf74d5ce15","added_by":"auto","created_at":"2024-06-25 11:00:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4983339,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4624656/v1/ea999c4a-919b-4d8e-ab67-593ad4be5966.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eAssessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area.\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eTo date, several geological and geophysical studies have been carried out on the Pan-African Belt in Central Africa (Nguimbous et al., 2010, Abate Essi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e, and references therein), with a particular interest in the mapping of crustal formations and their evolution. Certainly, the contributions of these works have led to major modifications concerning the lithostratigraphy and geodynamic evolution of this geological complex. However, despite previous works and the exploitation and mining of marble in the study area, northern Cameroon remains a relatively poorly known and underexplored region. In fact, the Congo Craton-Adamawa-Yade boundary captured almost all the attention of previous works concerning the Pan African belt in Cameroon. Previous studies revealed that this area, because of its pivotal position between the East-Nigeria area in the west, belonging to the Trans-Saharan chain (Ferr\u0026eacute; et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1998\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), and the Mayo-Kebbi domain with juvenile crust to the East (Penaye et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Isseini, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2011\u003c/span\u003e), and the Adamaoua-Yad\u0026eacute; domain, delimited by the Tchollir\u0026eacute;-Banyo Fault (Toteu et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) to the south, would have been intensely affected by successive tectonic events of the Pan-African orogeny. As a result, the bedrock characterization in this area is poorly understood and poses problems related to i) the lithostratigraphy; ii) the nature of the contacts (intrusive, sedimentary, tectonic, metamorphic gradient) between the different sets; and iii) tectonic and geodynamic evolution and the implications for mineral resources. The aim of this work is to examine the metamorphic conditions through 2.75D geophysical modelling of aeromagnetic data in the Guider-Kaele area, northern Cameroon.\u003c/p\u003e"},{"header":"2. Geological and tectonic setting","content":"\u003cp\u003eThe Guider-Kaele area, which belongs to the Pan African domain in Cameroon, ranges between 09\u0026deg;45' and 10\u0026deg;45\u0026rsquo;N and 13\u0026deg;15' and 14\u0026deg;30\u0026rsquo;E. In this area, a soudano-Sahelian climate prevails. The average temperature is between 24\u0026deg;C and 36\u0026deg;C.\u003c/p\u003e \u003cp\u003eAs a part of the northern domain of the Central African Orogeny Belt (CAOB) in Cameroon, especially the Poli-Lere Group, the study domain consists of medium- to high-grade schists and gneisses of volcanic and sedimentary origin that formed in a magmatic back-arc context (Toteu et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) and Neoproterozoic syntectonic calc-alkaline granitoids (Penaye et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The post-Pan African tectonic calc-alkaline granitoids comprise mafic and felsic dykes crosscutting granites and syenite intrusions in schists and gneisses. They align along a NNW-trending line between batholiths (Toteu et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The above units are covered by unmetamorphosed sediments and volcanic rocks in several small basins (Toteu et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Van-Schmus et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The Palaeoproterozoic formations and Pan-African batholiths of the Adamawa-Yade domain (Houketchang et al., 2009) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) dominate the far southeast of the study area.\u003c/p\u003e \u003cp\u003eThree tectonic events affected the structural development of this domain, notably a crustal shortening and thickening event caused by collision between Neoproterozoic blocks followed by syn- to postorogenic shear movements (Toteu et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Ngako et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). A crustal shortening event is shown by gentle folding in isoclinal folds with flat-lying foliations formed by thrust faulting (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) (Ngako et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Later, compressional deformation is indicated by vertical and NNE-trending foliations and by tight upright to reclining folds (Ngako and Njonfang, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). In the Poli area, this deformation is accompanied by dextral and sinistral shearing (Dawai et al., 2013).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Aeromagnetic data acquisition and processing","content":"\u003cp\u003eThe aeromagnetic data used in this study were acquired from the Africa Magnetic Mapping Project (AMMP) surveys of PGW Ltd. (Paterson, Grant \u0026amp; Watson Limited) in collaboration with GETECH and ITC. The flight path was flown at 235 m above the topographic level with a line spacing of 750 m along the N135\u0026deg;E azimuth. Each individual survey was corrected for diurnal variations and gridded using a standard minimum curvature into one coherent dataset. Then, the regional magnetic field of the Earth or the International Geomagnetic Reference Field (IGRF) was removed from the signal to produce a residual magnetic field (TMI), which was gridded at 1/5 of the flight line spacing and displayed as a colour image. Then, the TMI grid was reduced to the equator (RTE) using the inclination and declination angles of the IGRF (-1.01\u0026deg; and \u0026minus;\u0026thinsp;3.96\u0026deg;, respectively). The RTE anomaly map (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) contains both small wavelength anomalies, high-intensity anomalies created by magnetized sources at the surface or at shallow depths, and longer wavelength anomalies related to deeper sources. To amplify the effect of the deeper sources, the RTE data were collected upwards to a height of 1 km above the Earth\u0026rsquo;s surface.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Methodology","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e4.1. The Euler deconvolution method\u003c/h2\u003e\n \u003cp\u003eEuler deconvolution (ED) is an analytical method based on Euler\u0026apos;s homogeneity equation (Thompson, \u003cspan class=\"CitationRef\"\u003e1982\u003c/span\u003e; Reid et al., \u003cspan class=\"CitationRef\"\u003e1990\u003c/span\u003e) that is used to estimate the apparent locations and depths of several subsurface features, particularly from magnetic or gravitational fields. The degree of homogeneity is expressed by the structural index, which measures the fall-off rate of the field with distance from the source, as shown by the following equation from Thompson (\u003cspan class=\"CitationRef\"\u003e1982\u003c/span\u003e) and Reid et al. (\u003cspan class=\"CitationRef\"\u003e1990\u003c/span\u003e):\u003c/p\u003e\n \u003cp\u003e\u003cimg 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\"\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eFor magnetic data, N takes values from 0 to 3 (Thompson, \u003cspan class=\"CitationRef\"\u003e1982\u003c/span\u003e; Reid et al., \u003cspan class=\"CitationRef\"\u003e1990\u003c/span\u003e). Reid et al. (\u003cspan class=\"CitationRef\"\u003e1990\u003c/span\u003e) showed that only low structural indices (0 to 1) provide the best depth estimates. The Euler depths appear wherever there are lithological discontinuities in the geological formations. They represent the structural and/or stratigraphic changes in various geological formations (Owona-Angue et al., 2013).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e4.2. Magnetic modelling\u003c/h2\u003e\n \u003cp\u003eFor the present study, forward modelling of the source body was performed with the GM-SYS module in Oasis Montaj v8.4 to obtain the optimal fit of the generated source model to the magnetic data. The GM-SYS module helps to calculate the magnetic response from a geological cross-section model. The methods used to calculate the model\u0026rsquo;s response are based on the methods of Talwani et al. (\u003cspan class=\"CitationRef\"\u003e1959\u003c/span\u003e) and Talwani and Heirtzler (\u003cspan class=\"CitationRef\"\u003e1964\u003c/span\u003e), as well as the algorithms described by Won and Bevis (\u003cspan class=\"CitationRef\"\u003e1987\u003c/span\u003e). Two-and-a-half-dimensional calculations are based on Rasmussen and Pedersen (\u003cspan class=\"CitationRef\"\u003e1979\u003c/span\u003e). The GM-SYS inversion routine utilizes a Marquardt inversion algorithm (Marquardt, \u003cspan class=\"CitationRef\"\u003e1963\u003c/span\u003e) and the USGS computer program SAKI (Webring, \u003cspan class=\"CitationRef\"\u003e1985\u003c/span\u003e) to linearize and invert the calculations.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"5. Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e5.1. Analysis of total magnetic anomaly intensity reduced to the equator (RTE)\u003c/h2\u003e \u003cp\u003eThe RTE magnetic map (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) reveals anomaly values between \u0026minus;\u0026thinsp;77 and 300 nT, corresponding to magnetic anomalies covering a wide range of amplitudes and wavelengths. A correlation between the anomalies and some morphological features, such as faults, geological contacts and outcrops, can be inferred. Within northwestern Cameroon, these magnetic anomalies seemingly correlate with Proterozoic granitic and metamorphic lithologies, including metavolcanic rocks, gneisses, and schists (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The RTE map contains mainly northeast-trending minima and maxima anomalies that are roughly parallel to the Proterozoic synorogenic strike-slip episodes (Ngako et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The most prominent anomalies are a series of large wavelengths, low-amplitude magnetic maxima (anomalies 1 and 2) and slightly greater magnetic-amplitude minima (anomalies 3 and 4) in the northern portion of the map (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The magnetic maxima are caused by lithologies with lower magnetic susceptibility. Anomalies 1 and 2 occur over the medium- to high-grade gneisses of the NW Cameroon terrane and post-Pan African sediments. In contrast, anomalies 3 and 4 occur over metamorphic Precambrian substrata (ectinites and migmatites) overlain by sedimentary formations (Regnoult, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e1986\u003c/span\u003e) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The extent of these low-amplitude magnetic maxima implies that the magnetic susceptibility of the gneisses is relatively low, with some regions (small wavelength maxima within the region of anomaly 1) having higher susceptibility values. This could be due to high-grade gneisses or isolated mafic or metaigneous bodies (Ngoh et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In fact, in the study area, the level of weathering of rocks is highly variable. For example, the outcrops encountered and observed in situ show folded, faulted and fractured rocks with some weathering facts available on the ground surface. This weathering impacts the petrographic and geochemical characteristics of rocks and thus the magnetic susceptibility of these rocks.\u003c/p\u003e \u003cp\u003eThe upwards continued RTE map (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e)\u003c/span\u003e exhibits similar patterns of high and low magnetic anomalies, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The upwards continued RTE anomaly ranged from \u0026minus;\u0026thinsp;164.47 to 288.31 nT. The upwards continued RTE map is basically a smoothed version of the RTE map and contains prominent negative (long wavelength) anomalies distributed in the northeastern, central, and southern parts of the study area. This map clearly highlights positive and negative prominent anomalies roughly elongated in the ENE‒WSW direction. The persistence of prominent anomalies with great wavelengths, low-amplitude magnetic maxima (anomalies 1 and 2) and slightly greater-amplitude magnetic minima (anomalies 3 and 4) observed in the northern portion of the map (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) shows that they are associated with deeper structures. In addition, the upwards continued RTE map shows attenuated anomalies (anomalies 8, 9 and 10) that are also related to upper crustal lithologies.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe distribution of these different patterns clearly suggests that the study area is characterized by zones of high and low magnetic susceptibility within different lithologies at depth. Microfaults and microfolds observed in the field were more developed and prevalent within some metamorphic rocks. The structures have various strikes (NE‒SW, NNE‒SSW and E‒W) and subvertical dips, in accordance with the regional structures controlling them. These faults could have been caused by vertical movements due to subsidence of the basin and lateral movements due to shearing and could have affected the substratum (Cimencam, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Mapping observations revealed that there was more than one deformation phase. The geodynamic environment corresponds to a sedimentary basin (Mayo Oulo-Lere basin) put in place during the initiation of the South Atlantic opening (Regnoult, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e1986\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e5.2. Depth estimates\u003c/h2\u003e \u003cp\u003eThe Euler deconvolution technique is an analytical method chosen for detecting the locations and depths of different features from obtained anomalies. This study focuses on geological boundaries, faults and dyke locations. The structural indices used are 0.25 and 1.25, corresponding to ideal geometrical contacts and faults, respectively (Barbosa et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1999\u003c/span\u003e). Euler deconvolution is applied to the magnetic RTE field with a 20 km x 20 km window size in the Oasis Montaj Program v.8.4, which provides better resolution for the solutions. The obtained Euler\u0026rsquo;s solution maps are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ea\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eb\u003c/span\u003e. These solutions are relatively consistent with short- and long-wavelength anomalies related to different tectonic features and some lithological formations in the study area. The depths of the faults and contacts ranged from 0.39 km to 11.44 km in the NNW‒SSE, NE‒SW, NW‒SE, and E‒W directions.\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e5.2.1. Euler solutions for structural index SI\u0026thinsp;=\u0026thinsp;0.25\u003c/h2\u003e \u003cp\u003eThe solutions for a structural index of 0.25 (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ea)\u003c/span\u003e are located between 0.39 km and 6.6 km depth, with an average depth of 2.32 km. These solutions are more clustered and mainly follow the NW‒SE, NE‒SW and E‒W directions. Most of these solutions represent deep-seated structural features. The surface features and resulting lineaments are located above 0.39 km in depth. The moderately deep-seated solutions are in the central, eastern and southwestern parts of the study area, while the depth solutions of other parts of the area are relatively shallow under an average depth, thus inferring shallow magnetic anomaly sources. In accordance with the geodynamic model proposed by Toteu et al. (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2004\u003c/span\u003e), the configuration observed in the area suggests the presence of two collisional blocks: the southern block with a passive and older margin and the northern block with an active margin. This collision generated intense deformation in the North Cameroon domain due to the penetration of the rigid block into the active margin (Abdelsalam et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2002\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e5.2.2. Euler solutions for structural index SI\u0026thinsp;=\u0026thinsp;1.25\u003c/h2\u003e \u003cp\u003eThe Euler solutions for the structural index of 1.25 (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eb)\u003c/span\u003e provide a depth range from 0.76 km to 11.44 km. As shown previously, there are more similarities and clusters of solutions with solutions for a structural index of 0.25. The observed abundance of solutions in the study area implies the existence of a broad set of dykes or vertical faults. These clusters are crosscut by those due to deep magnetic sources (\u0026ge;\u0026thinsp;5 km) oriented NE‒SW, which have linear stacks of solutions predominant in the NE‒SW, NNW‒SSE, E‒W and NW‒SE directions. There is a lack of solutions in the northern, western, eastern, and southern margins of the study area.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patterns of Euler depths (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ea\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eb\u003c/span\u003e) obtained by interpolation of each structural index are similar and show that the bedrock of the study area is strongly affected by intermediate and deep tectonic features (\u0026ge;\u0026thinsp;3 km), which seem not to exceed a depth of 7 km. The values obtained are within the range of those obtained by previous researchers in the area. There is also a concentration of deep magnetic sources mainly along the NE‒SW to ENE‒WSW directions. This zone is particularly a large-scale apparent average depth zone oriented along the Mousgoy-Moutouroua axis, which would have imposed these preferential directions in both cases. This axis, which contains a set of granitoids and orthogneisses, would therefore be dominated by the structural imprint of the metagongroses of the Mayo-Kebbi domain. Some previously known lineaments and features in the area are highlighted through a clustering of solutions that coincide with their directions. Then, a general trend in the zone of weakness can be observed and linked to the regional tectonic features encountered in the study area.\u003c/p\u003e \u003cp\u003eAccording to both Euler maps, the northeastern area has no more solutions, which implies extremely weak tectonics in that zone. The deepest geological features are located below 5 km; they follow the NNE\u0026ndash;SSW, E‒W and NNW‒SSE directions and dominate the study area.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e5.3. Magnetic modelling\u003c/h2\u003e \u003cp\u003eIn general, the shape of an anomaly can help to determine the shape and position of density or magnetic contrasts. Theoretically, several geometries will fit a particular anomaly. However, in practice, using realistic geological or other geophysical controls, anomaly fits provide real numerical constraints on anomaly sources (Prieto \u0026amp; Pratsch, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). Furthermore, the shape and amplitude of the magnetic response depend on many other variables in addition to the concentration of magnetic minerals present, which include the geometry and depth of the deposit, its orientation relative to the magnetic field to the north and the inclination of the Earth\u0026rsquo;s magnetic field at its location (Prieto \u0026amp; Pratsch, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Okiwelu et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2011\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, four geological cross sections were modelled from the RTE map (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e6\u003c/span\u003e) with a 2.75D forward modelling approach in GM-SYS. These models were constrained by geological knowledge, borehole data (Cimencam, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) with a maximum depth of 69 m and Euler depths of the study area, and models with a root mean square (RMS) less than 5% were accepted.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e5.3.1. Profile 1\u003c/h2\u003e \u003cp\u003eThe magnetic north‒south cross-section P1 is situated near the Mindif-Kaele axis and is approximately 56 km long. Along this transect, the magnetic field anomaly intensity oscillates between \u0026minus;\u0026thinsp;255.42 nT and 363 nT (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e7\u003c/span\u003e). This is possibly caused by subsurface discontinuities or major formations. The magnetic field decreases to -255.42 nT at approximately 11.4 km, while it peaks at 363 nT at approximately 19.3 km from the north. This variability in the magnetic field intensity along the transect reflects the heterogeneity of the Earth's crust.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe modelled geological section highlights a subsurface sequence formed by a sedimentary cover including detrital sediments, lagoon-lacustrine sandstones, or arkose-sandstones with a magnetic susceptibility of 0.0209 SI. The latter are bottomed by schists (with a magnetic susceptibility of 0.003 SI), which overlie a crystalline, tabular, and faulted basement. The whole basement consists of gneissic and granitic formations (syn-tectonic granites) with susceptibilities of 0.025 SI and 0.05 SI, respectively. This geological model also highlights a prominent intrusion or batholith overlain by sedimentary formations that extend down beyond 10 km depth into the crystalline basement. The magnetic susceptibility (0.051 SI) of this intrusive batholith suggested that it could be a granodiorite or syenogranite, which are members of the granitoid group. In addition to the observed batholith, this model also reveals a strongly faulted crystalline basement that allowed small magmatic intrusions or magmatic lift during metamorphism.\u003c/p\u003e \u003cp\u003eThe progressive uplift of the crystalline basement formations from north to south suggests a zone of surrection, the consequence of which would be the rise of the granito-gneissic or granito-migmatitic basement, which would result from the Pan-African orogeny. In addition, given the stratigraphy and apparent geometry of the basement, this geological model reveals a sedimentary basin with crystalline bedrock, which, according to Bessoles and Trompette (1980), constitutes the envelope form and emphasizes the synclinal termination of the Maroua volcano-detrital vein.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e5.3.2. Profile 2\u003c/h2\u003e \u003cp\u003eMagnetic profile P2 is also north‒south, measures approximately 84 km in length, and cuts the study area longitudinally along the Guider-Figuil axis. Along this transect, the observed magnetic field anomaly varies from \u0026minus;\u0026thinsp;67.9 to 210 nT. The profile is irregular, and the occurrence of many peaks indicates the presence of discontinuities or geological features (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e8\u003c/span\u003e). The fairly high magnetic signal in contrast to that in the first profile is a probable signature of near-surface high magnetic susceptibility formations.\u003c/p\u003e \u003cp\u003eLike in transect P1, the geological model is a three-layered subsurface. The sedimentary cover (k\u0026thinsp;=\u0026thinsp;0.0209 SI) consists of limestone, conglomeratic arkosic and ferruginous sandstone layers; then, a schist layer (k\u0026thinsp;=\u0026thinsp;0.003 SI) is bottomed by a basement made up of gneisses (k\u0026thinsp;=\u0026thinsp;0.025 SI) and granites (k\u0026thinsp;=\u0026thinsp;0.05 SI).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition, this geological model highlights intense fracturing of the crystalline substratum, whose northern block seems to have collapsed while the southern block has moved up. This apparent configuration suggests the existence of multiple faults with vertical displacement and justifies the presence of a crystalline basement uplift observed along this cross section. Therefore, the model\u0026rsquo;s general architecture suggests that regional metamorphism heavily affected the local basement. This general architecture and the lithology derived from the model therefore highlight that the combined effects of intense tectonic activity and regional metamorphism heavily affected the basement of this area.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e5.3.3. Profile 3\u003c/h2\u003e \u003cp\u003eThe magnetic cross-section P3 is approximately 33 km in length in the NE‒SW direction and is located in the Bossoum-Dourbeye surroundings. Along this transect, the intensity of the magnetic field anomaly oscillates between \u0026minus;\u0026thinsp;55 and 155 nT. The 2.75D modelled subsurface sequence shows a downwards sedimentary cover lying on top of the schists, and these two geological formations (sedimentary cover and schists) overlie a crystalline faulted basement, which consists of gneisses and granites. The model also highlights a dolerite (k\u0026thinsp;=\u0026thinsp;0.062 SI) rooted in the gneisses, which would have been emplaced during the syn-orogenic reactivation phases. Therefore, this hypabyssal intrusion resulted from swarms of dikes emanating from a large intrusive body at depth and was facilitated by fracturing of the gneissic formations or lithostratigraphic contact.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e5.3.4. Profile 4\u003c/h2\u003e \u003cp\u003eMagnetic profile P4 extends more than approximately 10.40 km in the NW‒SE direction and intersects profile P3. Herein, the magnetic field intensity ranges between \u0026minus;\u0026thinsp;60 nT and 160 nT, with only two peaks, which could be due to the presence of an important geological structure or formation.\u003c/p\u003e \u003cp\u003eThe geological model (Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e10\u003c/span\u003e) almost conforms with the previous models despite some differences in the shape and amplitude of the anomaly. From northwest to southeast, there is a relative rise (thickening) of the granitic bedrock and thus a thinning of the sedimentary cover, probably resulting from regional isostatic compensation. Like the previous model, this model also suggests the presence of a synform or syncline with a granitic-gneissic basement filled by schist formations.\u003c/p\u003e \u003cp\u003eFracturing with granitic basement infiltration occurs near the northern flank. The southern flank of this syncline was subjected to major fracturing of the granitic bedrock, which was filled by the schist layer. These subsurface faults, fractures, or parts of the geological layers could test the extent and impacts of the tectonic events that occurred during the Pan African orogeny.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition, the modelled crystalline basement sometimes collapsed or rose and was dotted with subbasins of the sedimentary layer. From northwest to southeast, the geomorphology of this granitic basement suggests an uplifted zone, which results from isostatic compensation, and the presence of a probable granitic unconformity or schistogneissic layer affected by an extensional trough. The thickness of the schist layer, which results from the metamorphism of sedimentary formations with carbon or clayey materials, indicates the extent of the sinking of this synform or syncline.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"6. DISCUSSION","content":"\u003cp\u003eThe Euler deconvolution solution map highlights more clustered solutions from south to north of the study area. Generally, the Euler solutions for different structural indices show a depth range of 0.39 km to 11.44 km (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). The greatest depth of geological features is found in the central part of the study area and is relatively scattered around the southwestern edge. The basement rocks in the northwest and southeast regions are relatively shallow. These clustered solutions highlighted several main E‒W, NE‒SW and NW‒SE trends, which fit the regional trends. With regard to the major directions, spatial distributions, and roof depths of the investigated structures obtained by the application of Euler\u0026rsquo;s deconvolution method, these geological formations would indeed be deep-seated. The structural trends highlighted suggest that the main NE geological feature is the tectonic imprint of the Katanguian orogeny, which controls the tectonic arrangement of the Pan-African domain and was confirmed by the Massenya-Ounianga heavy gravity anomaly line (Poudjom-Djomani et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1995\u003c/span\u003e, Abate Essi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In addition, according to some authors (Poudjom-Djomani et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Loule et al., 2009; Ganno et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2010\u003c/span\u003e), this dominant structural trend could also be due to the opening of the South Atlantic Ocean, for which the direct insight was the collapse of the unstable corridor of northern Cameroon and southern Chad, with a main NNE‒SSW structural trend (Cornachia \u0026amp; Dars, 1983). Thus, this configuration suggests the earlier hypothesis for global NE‒SW geological and tectonic features.\u003c/p\u003e \u003cp\u003eThe geological models obtained through 2.75D modelling highlight a mainly faulted geological environment. These geological models revealed sedimentary, metamorphic, and igneous formations overlying a syntectonic granitic basement. The presence of strongly foliated metamorphic rocks such as schists and gneisses in this area suggests that this region could either have been affected by regional metamorphism or originated from deformation under differential stress conditions resulting from tectonic forces, as witnessed by the several metamorphosed rocks occurring in the eroded mountain chain (e.g., as seen in Mindif surroundings) (Stephen, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The hypothesis of regional metamorphism seems to be confirmed by the presence of a thick schist layer in the four subsurface 2.75D models. In addition, according to previous geophysical works and geological information (Poudjom et al., 1993 \u0026amp; 1995; Kamguia et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Nguimbous et al., 2010), with regard to the geometry, thickness, and spatial disposition of layers, the dominant metamorphic facies in the area under study result from high-temperature and high-pressure geothermal gradients.\u003c/p\u003e \u003cp\u003eThese geological models also highlighted faulting and a southwards progressive thickening of the crust. This occurs because the crust in that area sinks farther either to compensate for the added weight or to react to compressional stresses in the rocks due to tectonic forces. The upwelling or crustal thinning zones, considering the hypothesis of an isostatic phenomenon, could be due to a shallow or deep prominent magmatic source. Several authors (Kamguia et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Nguimbous et al., 2010) have linked this configuration to the tectonic accidents affecting this region. For example, those affecting Central Cameroon with the establishment of horsts represented by the Adamawa granites or an E‒W extension phase prevailed on the Cameroon Volcanic Line (Popoff et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1983\u003c/span\u003e, Reusch et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Therefore, the several probable subbasins observed in these modelled transects could result from the manifestations of regional isostatic compensation following the elevation of the Adamawa horst, which is in isostatic equilibrium at altitudes below 1000 m (Poudjom et al., 1993). In addition, since the Pan-African belt, in which the study area is located, underwent various tectonic events marked by several rifting phases characterized by prerift deformation followed by crustal thinning. Accordingly, with Poudjom et al. (1995), the idea of crustal thinning on a regional scale seems more plausible.\u003c/p\u003e \u003cp\u003eFurthermore, the modelled sections revealed several high magnetic signatures interpreted as intrusions with different susceptibility values. These intrusions vary from one profile to another and suggest potential mineralization zones in this region. Their presence could result from the upwelling of igneous material in the area, probably through diapiric activity, which is a sliding regime leading to the segregation of granodioritic magma (Pons et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). In fact, the green schist facies encountered in the field results from thermal changes leading to the transformation of clays (shale) and limestone into schists and marble, respectively, reaching the green schist facies. This modified the original stratification of the layers observed in the field, giving them a subvertical dip. This hypothesis could explain the presence of high magnetic susceptibility (k\u0026thinsp;=\u0026thinsp;0.051 SI) granodiorites observed in profile P1 near Mindiff and another high susceptibility intrusion (k\u0026thinsp;=\u0026thinsp;0.062 SI) in profile P3. In addition to syntectonic plutonism resulting in occasional erosion of orthogneisses, this area records Pan-African late- and postorogenic intrusive rocks such as Mindiff syenite or granodioritic rocks. The evidence of these various intrusive bodies is facilitated by a densely fractured basement, which allows upwelling of mantle materials leading to several batholiths or dikes, swarms all emanating from a large intrusive body at depth. These faults likely weaken the crust in various areas; if they are not filled by crustal material, they are filled by sedimentary or volcano-sedimentary formations.\u003c/p\u003e"},{"header":"7. Conclusion","content":"\u003cp\u003eIn this region, magnetic modelling of the four profiles improved on the reduced-to-equator anomaly map. The reduced to equator anomalies (RTE) map displays magnetic anomalies covering a wide range of amplitudes and wavelengths, with a relatively good correlation between the anomalies and some morphological features, as observed in northwestern Cameroon. The reduced to equator anomalies (RTE) map presents mainly northeast-trending minima and maxima anomalies that are roughly parallel to the strike-slip tectonic episodes. Euler\u0026rsquo;s deconvolution highlights more clustered solutions from south to north characterized by depth values ranging from 0.39 km to 11.44 km. These clustered solutions highlighted several main E‒W, NE‒SW and NW‒SE trends, which fit the regional trends. The 2.75D forward models obtained highlight faulted and folded geological facies characterized by the presence of several metamorphic rocks. This study suggested that the area was affected by many tectonic features during the Pan African orogeny. Several unconformities materialized by folded and faulted basement or synclinal troughs separated by anticlinal ridges have been highlighted.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data used to support the findings of this study are available from the corresponding\u0026nbsp;author\u0026nbsp;upon request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that there are no conflicts of interest regarding the publication of this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The authors are grateful to the reviewers for their constructive comments.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAbate Essi, J.M., Marcel, J., Yene Atangana, J.Q. et al., 2017. Interpretation of gravity data derived from the Earth Gravitational Model EGM2008 in the Center-North Cameroon: structural and mining implications. Arab J Geosci 10, 130 (2017).\u003c/li\u003e\n \u003cli\u003eAbdelsalam, M.G., Li\u0026eacute;geois, J.-P., Stern, R.J., 2002. The Saharan Metacraton. Journal of African Earth Sciences, 34, pp.119-136.\u003c/li\u003e\n \u003cli\u003eBarbosa, V.C.F., B. C. Joao and W.E. Medeiros, 1999.\u0026nbsp;Stability analysis and improvement of structural index estimation in Euler deconvolution: Geophysics, 64, pp. 48-60.\u003c/li\u003e\n \u003cli\u003eBessoles, B. et Trompette, M., 1980. G\u0026eacute;ologie de l\u0026rsquo;Afrique. La cha\u0026icirc;ne Pan-Africaine \u0026laquo;\u0026nbsp;Zone Mobile\u0026nbsp;\u0026raquo; d\u0026rsquo;Afrique Centrale (partie sud) et zone mobile soudanaise. M\u0026eacute;m. 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The Pan-African quartz-syenite of Guider (North-Cameroon): Magnetic fabric and U‒Pb dating of a late-orogenic emplacement, Precambrian Research, http://dx.doi.org/10.1016/j.precamres.2013.07.008.\u003c/li\u003e\n \u003cli\u003eFerr\u0026eacute;, E.C, Gleizes, G., Caby, R., 2002.\u0026nbsp;Tectonics and postcollisional granite emplacement in an obliquely convergent orogen: The Trans-Saharan belt, Eastern Nigeria. Precambrian Research, 114, pp. 199-219.\u003c/li\u003e\n \u003cli\u003eFerr\u0026eacute;, E.C., Caby, R., Peucat, J.J., Capdevila, R., Moni\u0026eacute;, P., 1998. Pan-African, postcollisional, ferro-potassic granite and quartz-monzonite plutons of Eastern Nigeria. Lithos, 45, pp. 255-279.\u003c/li\u003e\n \u003cli\u003eGanno, S., Nzenti, J.P., Ngnotue, T., Kankeu, B. and Kouankap, N.G.D., 2010. Polyphase deformation and evidence for transpressive tectonics in the Kimbi area, Northwestern Cameroon Pan-African fold belt. Journal of Geology and Mining Research. 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Semiautomatic Marquardt inversion of gravity and magnetic profiles. U.S. Geological Survey Openfile Report OF-122. 110 p.\u0026nbsp;doi: 10.3133/ofr85122\u003c/li\u003e\n \u003cli\u003eWon, I.J. and Bevis, M., 1987. Computing the Gravitational Magnetic Anomalies Due to a Polygon: Algorithm and FORTRAN Subroutines. Geophysics, 52, pp. 232-238.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"2.75D forward modelling, Pan African Belt, volcano-sedimentary layer, thermal history, crustal thinning.","lastPublishedDoi":"10.21203/rs.3.rs-4624656/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4624656/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, aeromagnetic data were used to construct a geological model of the Guider-Kaele area in northwestern Cameroon, which is part of the northern segment of the Pan-African belt in Cameroon. The area is dominated by the Poli and Mangbei lithostratigraphic Groups (Neoproterozoic metasedimentary rocks and metavolcanic rocks) intruded by late Pan-African granitoids and tertiary ring complexes. For quantitative analysis, 2.75D forward modelling of these magnetic data was performed using Oasis Montaj v. 8.4 along four transects oriented N‒S (two lines), NNE‒SSW and NNW‒SSE.. Well log information, borehole data, geologic maps, previous geophysical studies, and Euler deconvolution depth estimates constrained the models derived. In particular, Euler\u0026rsquo;s deconvolution estimated the depth to the magnetic sources (faults and some intrusions) in the 0.39 km to 11.44 km range beneath sea level. Furthermore, the proposed geological models highlight a subsurface composed of a volcanic-sedimentary cover overlying a granitic faulted basement, with some igneous intrusions (doleritic dyke swarms and granodiorites) and several troughs filled with volcanic-sedimentary deposits. In addition, these models reveal that the crust is thinning. The presence of a prominent greenschist layer in this area testifies to the thermal history or degree of metamorphism of its bedrock.\u003c/p\u003e","manuscriptTitle":"Assessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-25 10:35:56","doi":"10.21203/rs.3.rs-4624656/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f7c89c36-814a-41dd-aa3d-9570c5efb217","owner":[],"postedDate":"June 25th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":33608895,"name":"Geophysics"},{"id":33608896,"name":"Planetary Science"}],"tags":[],"updatedAt":"2024-06-25T10:35:56+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-25 10:35:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4624656","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4624656","identity":"rs-4624656","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}