South Cameroon Research Articles

Infants Dermatitis in the Pediatric Unit of Regional Hospital Ebolowa in South Cameroon

Infants Dermatitis in the Pediatric Unit of Regional Hospital Ebolowa in South Cameroon

Assessing climate change vulnerability and local adaptation strategies in adjacent communities of the Kribi-Campo coastal ecosystems, South Cameroon

This study assesses vulnerability to climate change and local adaption strategies in the Kribi-Campo coastal area. Variables of exposure, sensitivity and adaptive capacity are described and assessed based on the community's perception and biophysical evidence. Historical changes in rainfall and temperature variables, mangrove cover and occurrence of extreme climatic events are taken as indicators of exposure. Losses of property and income structure are used as indicators of sensitivity. Human, natural, social, financial and physical assets are used as elements of adaptive capacity. Focus group discussions were held with key informants in 12 settlements, and a survey was conducted with 150 household representatives (14 Bagyeli pygmies and 136 Bantou) to gather perceptions on climate change and adaptation strategies. Results show evidence of increased -vulnerability due to decreasing rainfall and irregular rainfall patterns, increasing occurrences of extreme climatic events and increased levels of coastal erosion. These have resulted in several effects, most significantly in the decline of agricultural production, reported by 57% of respondents, and damages to housing reported by 30% of respondents. Adaptive capacities are low. >60% of respondents do not use any adaptation strategy. All sectors considered, the identified responses to climate related phenomena include early harvesting of crop, farm abandonment, change of productive activity, change of farm location, house reinforcement. The study concludes that households living here are susceptible to the possible impacts of climate change. Income diversification, mangrove afforestation and climate education should be considered as priorities for adaptation in this area.

Pesticide Usage and Implications of the Diurnal and Seasonal Dynamics of Cocoa Hemipteran Pests on their Management in South Western Cameroon

Pesticide Usage and Implications of the Diurnal and Seasonal Dynamics of Cocoa Hemipteran Pests on their Management in South Western Cameroon

Questionnaire survey of the pan-African trade in lion body parts.

The African lion is in decline across its range, and consumptive utilisation and trade of their body parts and skins has been postulated as a cause for concern. We undertook a pan-African questionnaire and literature survey to document informed opinion and evidence for the occurrence of domestic and international trade and consumption in African lion body parts across current and former range states. Sixty-five people from 18 countries participated in the online questionnaire survey (run from July 2014 to May 2015), with information provided for 28 countries (including 20 out of 24 countries believed to have extant populations). Respondents were experts within their professional spheres, and 77% had ≥6 years relevant experience within lion conservation or allied wildlife matters. Their opinions revealed wide sub-regional differences in consumptive use, drivers of trade, and access to lions that impact wild lion populations in different ways. Traditional medicine practices (African and Asian) were perceived to be the main uses to which lion body parts and bones are put domestically and traded internationally, and there is reason for concern about persistent imports from former lion range states (mainly in West Africa) for parts for this purpose. The domestic, rather than international, trade in lion body parts was perceived to be a bigger threat to wild lion populations. Parts such as skin, claws, teeth and bones are thought to be in most demand across the continent. The impact of international trade on wild populations was acknowledged to be largely unknown, but occasionally was judged to be ‘high’, and therefore vigilance is needed to monitor emerging detrimental impacts. Seventeen countries were nominated as priorities for immediate monitoring, including: South Africa, Tanzania, Zimbabwe, Mozambique, Zambia, Botswana, Kenya, Nigeria, and Cameroon. Reasons for their selection include: prevalence of trophy hunting, ‘hot spots’ for poaching, active domestic trade in lion body parts, trade in curios for the tourist market, and histories of legal-illegal wildlife trade. This survey, and increased incident reports since mid-2015 of lion poisoning and poaching in Mozambique, Zimbabwe and South Africa, and sporadic poaching events in Uganda and Tanzania, are signalling an escalating trend in the trade of lion products that is an increasing threat to some national populations. The evidence is sufficient to make more detailed investigation of this trade a conservation priority.

Anatomical Characteristics of Garcinia lucida (Vesque) and Scorodophloeus zenkeri (Harms) Wood and Debarking Response in the South Region Cameroon

The aim of this work was to investigate the possible anatomical changes of Garcinia lucida and Scorodophloeus zenkeri after the removal of their bark. Debarking was done on individuals of each species at 1.30 m from the soil. The wound was rectangular in shape with 30 cm side. There was a follow-up every three months for nine months during which the survival and rate of regeneration of the bark were recorded. A block of cube was cut from the regenerated and intact wood of species for microtomy and microscopy activities. On the cross-section of each wood, vessel features like density and diameter were measured before and after wounding. Semi-automatic measurements were made using the SpectrumSee digital image analysis software. In the wood of the two species, it appeared that the density of the vessels before debarking was significantly comparable to the density after debarking, while the diameter of vessels in the regenerated wood was smaller. The cambial area increased slightly in the rainy season for all species. After nine months all the species started the restoration of their conductive zone. G. lucida heals its wound more rapidly than S. zenkeri.

Craterispermum capitatum and C. gabonicum (Rubiaceae): two new species from the Lower Guinean and Congolian Domains.

Craterispermum capitatum and C. gabonicum, two new species of Rubiaceae, are described from the Lower Guinea and Congolian Domains. Detailed descriptions and distribution maps are provided for each species, their conservation status is assessed and their taxonomic affinities are discussed. Craterispermum gabonicum is unique within the genus because of the strong dimorphism in brevistylous and longistylous flowers and inflorescences. We hypothesize that this species shows some form of dioecy. The distribution of C. capitatum shows a wide disjunction: the species is present in the Lower Guinean and Congolian Domains but absent from Gabon and South Cameroon. An identification key for the Craterispermum species present in the Lower Guinean and Congolian Domains is given.

<i>Garcinia lucida</i> Vesque (Clusiaceae): from traditional uses to pharmacopeic monograph for an emerging local plant-based drug development

Objectives: This paper seeks to assess information on the identity, traditional uses, safety and efficacy of Garcinia lucida Vesque (Essok in Boulou and Ewondo local language), in order to highlight it potential as species to be registered in medicinal plant list and formularies needed for the development of monographs leading to local production of phytomedicines. Methodology and Results: Ethnobotanical survey was carried in the Bipindi-Akom II region (South Cameroon) with the help of interviews based on standardised questionnaires addressed to key-informants. Bark and seeds were the major parts used, highly appreciated due to its properties in preventing consumers from poison, diarrhoea and headaches. The most important therapeutic indications were additive to palm wine, antidote to poisoning, gastritis and snake bite. Other uses in treating included gynaecological pains and infections, sexual diseases and cancers. The bark was also believed by local people to act on the stability of chemical antibiotic drugs in pharmacy, while leaves were used as insect repellent against mosquitoes and cockroaches. Conclusions and application of findings: As an additive in palm wine processing, poisoning antidote, aphrodisiac and medicines, bark and seeds are widely used in the Bipindi-Lolodorf-Akom II area, in the Centre and South regions of Cameroon, in Gabon and Equatorial Guinea, in Central Africa and West Africa. This similarity of use across many regions is considered as important biological activity marker tools guiding plant parts or species selection in drug discovery and development using ethnopharmacological approach. Through the ethnobotanical and biological tests, assessed, accurate information is provided to substantiate safety and efficacy of G. lucida and to satisfy the requirements of official compendia such as pharmacopoeia. Further studies are needed to understand the effects of bark and seeds as additive to palm wine, as well as the interaction between bark and chemical antibiotic drugs. Keywords: Garcinia lucida , traditional uses, medicinal plant list, monograph, pharmacopoeia, phytomedicine production

Identification of rare HIV-1 Group N, HBV AE, and HTLV-3 strains in rural South Cameroon

Surveillance of emerging viral variants is critical to ensuring that blood screening and diagnostic tests detect all infections regardless of strain or geographic location. In this study, we conducted serological and molecular surveillance to monitor the prevalence and diversity of HIV, HBV, and HTLV in South Cameroon. The prevalence of HIV was 8.53%, HBV was 10.45%, and HTLV was 1.04% amongst study participants. Molecular characterization of 555 HIV-1 specimens identified incredible diversity, including 7 subtypes, 12 CRFs, 6 unclassified, 24 Group O and 2 Group N infections. Amongst 401 HBV sequences were found a rare HBV AE recombinant and two emerging sub-genotype A strains. In addition to HTLV-1 and HTLV-2 strains, sequencing confirmed the fifth known HTLV-3 infection to date. Continued HIV/HBV/HTLV surveillance and vigilance for newly emerging strains in South Cameroon will be essential to ensure diagnostic tests and research stay a step ahead of these rapidly evolving viruses.

Magnetotelluric Investigation of the Geo-Tectonic Stability of Campo-Ma’an Area in South Cameroon

The magnetotelluric prospection method has been widely used in Cameroon not only as a reconnaissance method for geophysical investigations but also to determine the nature of the subsurface and the structural settings of the various geological formations in the country that resulted from the global geo-tectonic movements. The present study is aimed at employing the magnetotelluric method to provide evidence on major tectonic dislocations which might have led to the presence of plutonic intrusions in the cratonic structure of the Ntem Complex as well as determining the nature of the contact between the sedimentary Campo Basin and the metamorphic cratonic Ntem Complex. The analyses and interpretations of iso-resistivity maps and geoelectric sections from magnetotelluric data has enabled us to show that tectonic forces at contact between the sedimentary Campo Basin and the metamorphic Ntem Complex were of three different categories: gravity gliding, magmatic upwelling and lateral compressions. The results of the action of these forces were the development of vertical and sub-vertical faulting systems at Craton-Sedimentary Basin contact and subsidence of overburden that appears to have also paved the way for the setting-up of the Ntem River bed and its flood plains. This river bed and its flood plains have been characterized as having a sedimentary deposit depth of 500 m and width of 20 km. Meanwhile, the deep-seated contact faulting systems within the two identified formations have varied fault magnitudes with a maximum of 60 km. The relatively high apparently resistivity values (up to1.0 kΩ•m) for the sedimentary and the very high values for the metamorphic formations (up to and above 10.0 kΩ•m) suggest that the whole area is at present relatively geo-tectonically stable.

Magnetic Anomaly Interpretation of the Northern Congo Craton Boundary: Results from Depth Estimation and 2.5D Modeling

A magnetic-based geophysical study was performed across the southern part of Cameroon to investigate the boundary between the Archean Congo craton and the Pan-African metamorphic belt. Magnetic gradient techniques including Euler deconvolution and Tilt derivative have been applied to an aeromagnetic data profile to determine the depth of sources and their lateral extension. 2.5D magnetic modeling shows that the prominent magnetic positive anomalies observed on total magnetic map of south Cameroon are produced by deep and strongly magnetic bodies under the Pan-African formations mainly an important dyke formation structure with a high susceptibility of 0.041 (SI units), at an average depth of 4148 m and with a lateral extension of about 10 km. These bodies are interpreted to have emplaced at high crustal levels in a continental collision zone and were subsequently metamorphosed at granulite grade conditions, during the Pan-African orogeny about 620 Ma ago.

Antidiabetic activity of extracts of Anacardium occidentale Linn. leaves on n-streptozotocin diabetic rats

Anacardium occidentale L. (Anacardiaceae) is used in South Cameroon as well as in other tropical countries by traditional practitioners as a folk remedy for treatment of diabetes mellitus. We demonstrated the antidiabetic potential of the plant extracts in n-streptozotocin diabetic rats. The aim of the current study was to investigate the antidiabetic effects of ethanol extract of leaves of A. occidentale on neonatal streptozotocin diabetic rats.Two day old neonates were injected with 100 mg/kg of streptozotocin. At the end of the experimental period of 30 days, reduction in the fasting blood glucose levels, serum insulin, glycated hemoglobin levels, serum lipid parameters, and renal function biomarkers were estimated in the control and treated rats. Histopathological examination of liver, kidney and pancreas were also carried out.On administration of 100 mg/kg of plant extract, blood glucose levels of the rats showed 8.01% and 19.25% decrease in the fasting blood glucose levels on day 15 and day 30, respectively. The administration of extract showed that the effects of extract treatment are comparable to treatment with the standard drug Pioglitazone.These results demonstrate significant antidiabetic potential of the ethanol extract of leaves of A. occidentale, justifying the use of plant in the indigenous system of medicine. Further studies for investigating the specific compound(s) responsible for such beneficial role in diabetes would open new outlook in the therapy of type 2 diabetes.

Aggressive mosquito fauna and malaria transmission in a forest area targeted for the creation of an agro-industrial complex in the south of Cameroon

Baseline entomological information should be collected before the implementation of industrial projects in malaria endemic areas. This allows for subsequent monitoring and evaluation of the project impact on malaria vectors. This study aimed at assessing the vectorial system and malaria transmission in two ecologically different villages of the South-Cameroon forest bloc targeted for the creation of an agro-industrial complex. For four consecutive seasons in 2013, adult mosquitoes were captured using Human Landing Catch in NDELLE village (located along a main road in a degraded forest with many fish ponds) and KOMBO village (located 5km far from the main road in a darker forest and crossed by the Mvobo River). Morpho-taxonomic techniques were used alongside molecular techniques for the identification of mosquito species. ELISA test was used for the detection of circumsporozoite protein antigen of <em>Plasmodium falciparum</em>. Mosquito biting rate was higher in NDELLE than in KOMBO (28.18 <em>versus</em> 17.34 bites per person per night). Mosquitoes had a strong tendency to endophagy both in NDELLE (73.57%) and KOMBO (70.21%). Three anophelines species were identified; <em>An. gambiae</em>, <em>An. funestus</em> s.s and <em>An. moucheti</em> s.s.. <em>An. gambiae</em> and <em>An. funestus</em> s.s. represented the bulk of aggressive mosquitoes in NDELLE (n=10,891; 96.62%). <em>An. gambiae</em> was responsible for 62.6% and 77.72% of malaria transmission in KOMBO and NDELLE respectively. Mean entomological inoculation rate recorded in KOMBO and NDELLE were 4.82 and 2.02 infective bites per person per night respectively. Vector control was mainly based on the use of long-lasting insecticidal nets and indoor residual spraying. The degraded forest environment added to the presence of fishponds resulted in the increase of aggressive mosquito density but not of malaria transmission. The managers should use these data for monitoring and evaluation of the impact of their project; malaria control strategies should be included in their project in order to mitigate the risk of increased malaria transmission as a result of the implementation of their projects.

The national road 2 (NR2) and the Abang Minko’o border market functioning

The border market of Abang-Minko'o is one of the commercial hubs that drive the economy in the area of the three borders in the South Cameroon. This article discusses the role that the National Road 2 (NR2) plays in the functioning of this market Since it was put in place in 1992. To gather the data required for its completion, a methodology based on documentary research and the collection of primary data on the main survey sites, was used. Processed with computer, the data collected revealed that since 1992, the evolution of the border market activities in Abang Minko'o closely depends on the state of the National Road 2 (RN2) that dessert. Thus, during the 1990s, the volume of activities that place of trade remained low when this road had dirt and in poor condition. But after the asphalting of it and the bridge over the Ntem to Eking this volume began to grow gradually. In total, for this market to be functioning in full operation, the government should make every effort to maintain in good condition, the National Road (NR2) that dessert it

Synergies among social safeguards in FLEGT and REDD + in Cameroon

Two key international policy processes have been developed to combat illegal logging and promote the contribution of forests to climate change mitigation in developing countries: the European Union's Action Plan on Forest Law Enforcement, Governance and Trade (FLEGT) and its Voluntary Partnership Agreements (VPAs), and the United Nations Framework Convention on Climate Change policy on Reducing Emissions from Deforestation and Forest Degradation (REDD+). The implementation of these policies raises concerns about unintended adverse effects on the environment and local peoples' livelihoods. To prevent such effects, both processes involve developing country-level safeguards, so that they ‘do no harm’. This paper presents (i) a comparison of the social safeguards of the FLEGT-VPA and REDD+ processes and an explanation of their commonalities and differences, and (ii) an exploration of the potential synergies and the challenges to realizing them. The three main research methods used in the study were semi-structured interviews, content analysis of policy documents, and focus group discussions with local communities and indigenous peoples in south and east Cameroon. Our analysis shows that whereas FLEGT-VPA includes legality-based safeguards with legally binding monitoring and reporting obligations, REDD+ adopts a right-based approach to safeguards. Potential synergies between the two approaches were identified. The synergies lie in the participatory nature of the process of designing benefit sharing mechanisms, strengthening forest and land tenure, and defining the criteria and indicators in FLEGT-VPA and REDD+ safeguards. However, realizing the synergies is challenging, given the existing political economy of Cameroon.

Ferralsols in the Cameroon plateaus, with a focus on the mineralogical control on their cation exchange capacities

Land use intensity in the Cameroon plateaus, where Ferralsols and the associated highly weathered soils are dominant, has been steadily increasing, so that soil fertility status and its controlling factors on these plateaus should be elucidated to establish long-term land management strategies. Although it is known that Ferralsols have small, but variable CEC values, it has not been fully determined which clay components are the main source of CECclay in Ferralsols. Here, soils in three Cameroon plateau regions of different altitude (the lower South Cameroon (SC) Plateau with an altitude of 300–600m, SCL; the upper SC Plateau with an altitude of 600–900m, SCH; and the Adamawa Plateau with an altitude above 900m, ADM) were collected, and their physicochemical and mineralogical properties were investigated. The relative abundance of illitic minerals, which are a minor but the most promising source of CECclay in Ferralsols, was determined by using three indicators: the relative abundances of 1.0nm-thick structures as represented by XRD peak intensity (XRD1.0nm), structural K in illitic minerals as represented by clay-K content, and the quantity of intermediate interlayer sites between illite and vermiculite structures (i.e., frayed edge sites) as represented by the radiocesium interception potential (RIP). The relative abundances of two low-activity clay components, kaolinite and gibbsite, were determined by differential thermal analysis, and the degree of Al-substitution in goethite was determined by differential x-ray diffraction analysis. All three quantitative indicators for illitic minerals decreased along the altitude gradient, SCL>SCH>ADM, and were positively correlated with CECclay. While kaolinite also showed a decreasing trend at higher altitude, it did not show any significant correlation with CECclay. In contrast to the decrease in these Si-bearing minerals, gibbsite and Al-substituted goethite increased along the same altitude gradient. These associative changes strongly indicate that illitic minerals were the clay component largely controlling CECclay and that de-silication or aluminization may proceed at higher altitude or on stable surfaces with older formation ages in the Cameroon plateau regions. Thus, mineralogical properties well explained the distribution of Ferralsols; they were marginal in the SCL region, while those with relatively high CECclay were dominant in the SCH region and those with lower CECclay were dominant in the ADM region.

Biomedical research and capacity building: Bilateral collaboration between research institutes in South Africa and Cameroon

CITATION: Jacobs, G. B. & Ikomey, G. M. 2016. Biomedical research and capacity building : bilateral collaboration between research institutes in South Africa and Cameroon. South African Medical Journal, 106(10):953, doi:10.7196/SAMJ.2016.v106i10.11365.

Denudation rates on cratonic landscapes: comparison between suspended and dissolved fluxes, and 10Be analysis in the Nyong and Sanaga River basins, south Cameroon

AbstractSouth Cameroon is located in a tropical and tectonically quiescent region, with landscapes characterized by thick highly weathered regolith, indicative of the long‐term predominance of chemical weathering over erosion. Currently this region undergoes huge changes due to accelerated mutations related to a growing population and economical developments with associated needs and increasing pressures on land and natural resources. We analysed two of the main south Cameroon rivers: the Nyong River and Sanaga River. The Sanaga catchment undergoes a contrasted tropical climate from sub‐humid mountainous and humid climate and is impacted by deforestation, agriculture, damming, mining and urbanization, especially in the Mbam sub‐basin, draining the highly populated volcanic highlands. By contrast, the Nyong catchment, only under humid tropical climate, is preserved from anthropogenic disturbance with low population except in the region of Yaoundé (Méfou sub‐basin). Moreover the Nyong basin is dam‐free and less impacted by agriculture and logging.We explore both denudation temporal variability and the ratio between chemical and physical denudation through two catchment‐averaged erosion and denudation datasets. The first one consists of an 11‐year long gauging dataset, while the second one comes from cosmogenic radionuclides [CRNs, here beryllium‐10 (10Be)] from sand sampled in the river mainstreams (timescale of tens to hundreds of thousands of years). Modern fluxes estimated from gauging data range from 5 to 100 m/Ma (10 to 200 t/km2/yr); our calculations indicate that the usual relative contribution of chemical versus physical denudation is 60% and 40%, respectively, of the total denudation. Beryllium‐10 denudation rates and sediment fluxes range from 4.8 to 40.3 m/Ma or 13 to 109 t/km2/yr, respectively, after correction for quartz enrichment. These fluxes are slightly less than the modern fluxes observed in Cameroon and other stable tropical areas. The highest 10Be‐derived fluxes and the highest physical versus chemical denudation ratios are attributed to anthropogenic impact. Copyright © 2016 John Wiley & Sons, Ltd.

Xenomonitoring of sleeping sickness transmission in Campo (Cameroon).

BackgroundThe sleeping sickness focus of Campo in South Cameroon is still active, at a low endemic level, for more than a century, despite a regular medical surveillance. The present study focuses on the spatial distribution of xenomonitoring information obtained from an entomological survey performed in the dry season 2012. It appears that humans constitute a third of the blood meals and that the flies’ densities were coherent with those classically observed in the different biotopes. Paradoxically, the epicenter of the focus is the place where the risk indicators are the lowest ones.MethodsParticular attention was paid to the entomological device so that it covered the main part of human activities in the study area. One hundred and sixty-two pyramidal traps were used to catch tsetse flies twice a day that were identified, counted, dissected. Molecular analysis using classical and specific molecular markers was conducted to determine the importance of trypanosome infections and the nature of the feeding hosts. This information was used to calculate a Transmission Risk Index and to define a gradient of risk that was projected into a Geographical Information System.ResultsConventional entomological indicators such as species identification of tsetse flies or the Apparent Density per Trap per day, show that Glossina palpalis palpalis is the main species in the campo area which is classically distributed into the different biotopes of the study area. Molecular analysis reveals that humans constitute a third of the blood feeding hosts and that 20 % of the dissected flies were infected with trypanosomes, principally with Nannomonas. Nevertheless, one fly was carrying Trypanosoma brucei gambiense, the pathogen agent of sleeping sickness, showing that the reservoir is still active in the epicenter of the focus. Paradoxically, the Transmission Risk Index is not important in the epicenter, demonstrating that endemic events are not only depending on the man/vector contact.ConclusionXenomonitoring provides a valuable guide/tool to determine places at higher risk for vector/human contact and to identify trypanosomes species circulating in the focus. This information from xenomonitoring demonstrates that decision makers should include a veterinary device in a control strategy.

Enhancing evidence informed policymaking in complex health systems: lessons from multi-site collaborative approaches.

BackgroundThere is an increasing interest worldwide to ensure evidence-informed health policymaking as a means to improve health systems performance. There is a need to engage policymakers in collaborative approaches to generate and use knowledge in real world settings. To address this gap, we implemented two interventions based on iterative exchanges between researchers and policymakers/implementers. This article aims to reflect on the implementation and impact of these multi-site evidence-to-policy approaches implemented in low-resource settings.MethodsThe first approach was implemented in Mexico and Nicaragua and focused on implementation research facilitated by communities of practice (CoP) among maternal health stakeholders. We conducted a process evaluation of the CoPs and assessed the professionals’ abilities to acquire, analyse, adapt and apply research. The second approach, called the Policy BUilding Demand for evidence in Decision making through Interaction and Enhancing Skills (Policy BUDDIES), was implemented in South Africa and Cameroon. The intervention put forth a ‘buddying’ process to enhance demand and use of systematic reviews by sub-national policymakers. The Policy BUDDIES initiative was assessed using a mixed-methods realist evaluation design.ResultsIn Mexico, the implementation research supported by CoPs triggered monitoring by local health organizations of the quality of maternal healthcare programs. Health programme personnel involved in CoPs in Mexico and Nicaragua reported improved capacities to identify and use evidence in solving implementation problems. In South Africa, Policy BUDDIES informed a policy framework for medication adherence for chronic diseases, including both HIV and non-communicable diseases. Policymakers engaged in the buddying process reported an enhanced recognition of the value of research, and greater demand for policy-relevant knowledge.ConclusionsThe collaborative evidence-to-policy approaches underline the importance of iterations and continuity in the engagement of researchers and policymakers/programme managers, in order to account for swift evolutions in health policy planning and implementation. In developing and supporting evidence-to-policy interventions, due consideration should be given to fit-for-purpose approaches, as different needs in policymaking cycles require adapted processes and knowledge. Greater consideration should be provided to approaches embedding the use of research in real-world policymaking, better suited to the complex adaptive nature of health systems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12961-016-0089-0) contains supplementary material, which is available to authorized users.

Postrift depositional evolution and sequence stratigraphy from offshore subsurface data of the Kribi-Campo subbasin (Cameroon, West African margin)

Using 2D seismic data and well logs from the Kribi-Campo subbasin in the south Cameroon margin, we have analyzed the postrift succession with the aim of deriving a chronostratigraphic chart and identifying stratigraphic traps. The Kribi-Campo subbasin related to the rifting between Africa and South America could be divided into a structurally complex eastern depocenter and a relatively less disturbed western depocenter in which a break-up unconformity approximately 107.5 Ma underlined the beginning of postrift history. We have used the modern concepts of sequence stratigraphy to identify and characterize seven second-order (SS1, SS2, SS3, SS4, SS5, SS6, and SS7) sequences and one third-order (SS8) sequences grouped into three megasequences (A, B, and C) from Albian to Recent. Sequence 1 (Albian-Cenomanian) was characterized by a retrogradation overlying a lowstand progradational pattern. The SS2 (Campanian-Maastrichtian) and SS3 (Maastrichtian) sequences were deposited during a highstand normal regression. From Paleocene to Eocene, the deposition of sequences SS4–SS5 was controlled by the development of submarine fan turbiditic system related to a forced regression of coastline. From the Middle Miocene to Recent age, the SS6, SS7, and SS8 sequences have been characterized by the development of sigmoidal-oblique clinoforms of a deltaic system well observed in the northern part of the study area. We have studied a new undocumented phase of forced regression of Mio-Pliocene in age within the postrift sequence SS7. The forced regression phases are associated with the Paleogene and Neogene uplift. Relative sea-level curves were constructed and compared with the existing published curves. The processes involved in the formation of these sequences were interpreted as a combination of tectonics, sediment supply, and sea-level changes. Potential reservoirs embedded within the sequences include channel fill, shingled turbidites, slope fan, and basin-floor fan complex.