A new gravity survey was carried out in the northern part of the onshore Kribi-Campo sub-basin in Cameroon. The data were incorporated to the existing ones and then analyzed and modeled in order to elucidate the subsurface structure of the area. The area is characterized in its north-western part by considerably high positive anomalies indicative of the presence of a dense intrusive body. We find, 1) from the analysis of the gravity residual anomaly map, the high positive anomalies observed are the signature of a shallow dense structure; 2) from the multi-scale analysis of the maxima of the horizontal gradient, the structure is confined between depths of 0.5 km and 5 km; 3) from the quantitative interpretation of residual anomalies by spectral analysis, the depth to the upper surface of the intrusive body is not uniform, the average depth of the bottom is h 1 = 3.6 km and the depths to particular sections of the roof of the intrusion are h 2 = 1.6 km and h 3 = 0.5 km; 4) and the 3D modeling gives results that are suggestive of the presence of contacts between rocks of different densities at different depths and a dense intrusive igneous body in the upper crust of the Kribi zone. From the 3D model the dense intrusive igneous block is surrounded by sedimentary formations to the south-west and metamorphic formations to the north-east. Both formations have a density of about 2.74 g/cm 3 . The near surface portions of this igneous block lie at a depth range of 0.5 km to 1.5 km while its lower surface has a depth range of 3.6 km to 5.2 km. The shape of the edges and the bottom of the intrusive body are suggestive of the fact that it forms part of a broader structure underlying the Kribi-Campo sub-basin with a great influence on the sedimentary cover.How to cite this paper: Malquaire, K.P.R.,

In order to produce a more detailed structural and geometrical information, and determine sediments thickness along the Kribi-Campo sub-basin, statistical spectral analysis and horizontal gradient analysis of residual anomalies coupled with the Euler deconvolution approach were applied on the gravity data in the area. The results obtained from the 2D spectral analysis on anomaly grids gave a depth to the basement rocks of the basin from 0.60 km to 3.93 km. This represents the thickness of the sedimentary formations overlying the basement. The interpretation of the spectral analysis results indicated that the potential hydrocarbon field areas are situated between Kribi and Lolabe and at Campo given that those areas have the highest sedimentary thicknesses values. From the analysis of the horizontal gradient, deep faults mainly striking SW-NE have been traced and a structural map of the area has been produced. By applying the Euler deconvolution method to the gravity data, information about the depth and trend of the main subsurface structures have been obtained.

With the aim to produce a detailed structural map and then enhance the geological information of the south-western Cameroon, a field gravity study is carried out in the Kribi-Campo-Ma'an area (SW Cameroon). This study area is assumed to undergo pending active tectonics as witnessed by several earthquakes [1]. Besides, the area has been affected by some shears that gave rise to many major faults including the Kribi-Campo Fault (KCF). This N-S lineament is an active fault corresponding to the NW margin of the CC [2] [3] and related to the development of the Kribi-Campo basin. The gravity data analysis enables to highlight many deeply-seated structural features trending in the NE, NNE, N-S, NNW, NW and E-W directions in this region. The NW-SE trend is more strongly developed than the other identified trends and could have deeply affected the major NNE structure. The NNE-SSW to N-S fractures and faults which are local relays of the Kribi-Campo fault are related to the Kribi shear zone. The fairly good clustering observed on local maxima of the horizontal gradient magnitude enables to suggest that the contacts outlined have vertical to subvertical dips. However, a probable interpretation of these features is that they are vertical to subvertical faults which follow the aforementioned directions. The location of the study area in the gulf of Guinea suggests that it sustains tectonics related both to the equatorial and the south Atlantic oceans opening.How to cite this paper: Clotilde, O.A

This geothermal source prospecting work is carried out in order to respond to the energy deficit affecting the populations of South Cameroon in particular. The study combines audio-magnetotelluric (AMT) and Landsat 8 data for the geolocation of reservoirs, as well as the geological and tectonic information. The processing of these data defined 5 profiles and led to two-dimensional models of resistivity sections for each profile. The interpretation of the data identified a highly conductive zone with a resistivity ranged 1–10 Ω·m at an estimated depth of 1200 m in the locality of Menve’ele. The Landsat 8 data collected in this area during the same period enabled the elaboration of temperature and lineament anomaly maps of the study area. High-temperature areas with high lineament predominance correlate better with areas of low resistivity. For example, Menve’ele (A1) has a surface temperature range of 20°C–30°C and a high density of lineaments. By correlating these results with those provided by previous authors, the Menve’ele locality may be the target of a potential geothermal reservoir. A 3D resistivity model is built to better understand the variations of resistivity and their depths. The geological and tectonic information of the region confirm the tectonic origin of the faults and lineaments as well as the predominance of metamorphic and sedimentary formations.

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