ST
Maître de Conférences
Activité scientifique
Profil chercheur
Enseignant-chercheur à l’Université de Yaoundé I. Grade : Maître de Conférences.
Publications scientifiques
Félicité Ayaba, Wan-Ting Hsu, Brilliant Kandjim Nforba, Kwan‐Nang Pang, Jean Pierre Tchouankoué
Peguy Noel Nkouamen Nemzoue, Narelle Maia de Almeida, George Satander Sá Freire, Jean Pierre Tchouankoué, Arrissa Agathe Noucoucouk, Rafael De Mendeiros Lima
Quaternary and Environmental Geosciences
Bioclastic sediments have economic value due to their high concentration of calcium minerals and can be used as soil amendments in agriculture, in cement factories, for animal feed formulation, and in the cosmetic industry. In Brazil, they are widely exploited on the continental shelf. Although the sedimentary facies of the Ceará continental shelf are known, there is no information about the composition of bioclastic constituents, their diversity, and distribution. This study aims to identify the constituents of marine benthic communities and their relationship with abiotic factors such as depth, morphology, and sedimentary facies. To this end, analyses of remote sensing data, bathymetry, and sediment samples were conducted. Features such as submerged dunes (oblique, parallel, and transverse), beach sandstones, and paleochannels were observed, and, according to physiographic and morphological aspects, five zones were interpreted (1. suspended sediment zone, 2. transverse dune zone, 3. oblique dune zone, 4. reef construction zone, and 5. flatbed zone). Sedimentological analyses identified components with their respective relative frequencies: bryozoans (35.5%), calcareous algae (27%), foraminifera (12.3%), molluscs (12%), cnidarians (4%), echinoderms (3.9%), sponges (3.5%), and arthropods (1.7%). Principal component analyses (PCA) showed a positive correlation between the biotic components (calcareous algae, sponges, and cnidarians) and the abiotic factors (depth 20-40 m, zones 2 and 4 (Z2 and Z4), and the bioclastic gravelly sand facies (BGS)). Otherwise, arthropods tend to occur from 40 to 60 m depth and are commonly associated with the biolithoclastic sand facies (BLS), while echinoderms and molluscs tend to occur in shallower regions (0-20 m), associated with zone 1 (Z1) and to the bioclastic gravel (BG) and bioclastic sand with gravel (BSG). This research demonstrates the relationship between geology, geomorphology, and benthic marine life in the region and provides a valuable database for measuring and monitoring the area, which has attracted attention from various sectors of the Blue Economy, especially during the Decade of the Oceans.
Bovari Syprien Yomeun, Wei Wang, Jean Pierre Tchouankoué, Michele Sandra Kamguia Kamani, Kevin Igor Azeuda Ndonfack, Emmanuel Archelaus Afanga Basua
Arabian Journal of Geosciences
Valderez P. Ferreira, Thyego R. Silva, Mariucha Maria Correia Lima, Alcídes N. Sial, A.F. Silva Filho, Charles Henrique Neves et 2 autre(s)
SSRN Electronic Journal
Siggy Signe Nformidah-Ndah, Peter Tollan, Jörg Hermann, Jean Pierre Tchouankoué
Journal of African Earth Sciences
Clinopyroxene bearing spinel harzburgites recovered from Cenozoic alkaline basalts from the Kapsiki plateau were investigated with the aim of understanding depletion and enrichment processes in the subcontinental mantle below a major tectonic line. Concentrations of major and trace elements (including H) were determined in-situ in olivine, orthopyroxene , clinopyroxene and spinel by EPMA , LA-ICP-MS and FTIR . The xenoliths are refractory with high olivine (0.91–0.92) and orthopyroxene (0.92–0.93) Mg# coupled with relatively high modal proportions of clinopyroxene (5–8%) and a remarkably wide range in clinopyroxene Mg# (0.91–0.94), interpreted to reflect high degrees of partial melting followed by modal and chemical metasomatic refertilization. A fractional partial melting model of orthopyroxene trace elements in a depleted mantle indicates 20–30% of melting. Clinopyroxenes show two groups based on their CaO contents (18.7–18.9 and 20.6–22.6 wt %) suggesting a secondary origin and modal metasomatism . The low Ca clinopyroxenes were the latest to be formed, and the wide range of clinopyroxene Mg# shows a lack of equilibrium with the coexisting minerals. The high Ca clinopyroxenes record ancient metasomatic events that are also documented in orthopyroxene. Cryptic metasomatism is shown by strong progressive enrichments in LREEs and MREEs of orthopyroxene and clinopyroxene. Th vs La and Sr vs Nd of clinopyroxene are used to identify different generations of metasomatism. Ti/Eu vs (La/Yb) N and Zr/Hf systematics indicate that the metasomatising agent has both a carbonatite and a silicate component. The structural hydroxyl contents of the different mineral phases are very low (<1 ppm for olivine, 40–48 ppm for orthopyroxene and 164–277 ppm for clinopyroxene). The very low water contents compared to typical sub-continental peridotites could be attributed to the depleted nature of the xenoliths or reflect lower water activities of carbonatitic melts relative to alkaline melts. Estimated f O 2 values expressed as ΔlogFMQ, (where FMQ corresponds to the fayalite magnetite-quartz oxygen buffer) range from -0.42 to -0.26 and are consistent with minor OH stretching regions of 3520 cm - 1 in orthopyroxene, related to a ferric iron defect. The combination of textural investigations, major, and trace element and H 2 O data suggests that a refractory subcontinental mantle was affected by several episodes of intraplate metasomatism dominated by silicate-carbonatite melts above the North-Eastern end of the Cameroon Volcanic Line.
Noël-Aimée Kouamo Keutchafo, Nicole Armelle Wambo Simeni, Brillant Kandzi Nforba, Agathe Arrissa Noucoucouk, Josiane Demlabin Sonmo, Depesquidoux Tchato Tchaptchet et 2 autre(s)
Geosciences
In the western Cameroon, crop out several dyke swarms of Paleozoic–Mesozoic age. These dykes intrude the Precambrian basement in the southern continental part of the Cretaceous Cameroon Volcanic Line. In the Njimom area, two groups of mafic dykes that crosscut the Neoproterozoic basement rocks have been observed. A first group intrudes the mylonites whereas the second group intrudes the granites. The dykes are alkaline basalts and hawaiites. The mineralogical assemblage of both groups of dykes consists of plagioclase, clinopyroxene, altered olivine, and opaque oxides. The dykes that cross-cut the Precambrian mylonitic gneisses show moderate TiO2 (1.7–2.0 wt.%), low MgO (4.4–7.1 wt.%), and compatible trace element concentrations (e.g., Cr = 70–180 ppm; Ni = 30–110 ppm). The dykes that intrude the granites have TiO2 contents between 2.3 and 2.5 wt.% and moderate compatible trace element concentrations (e.g., Cr = 260–280 ppm; Ni = 170–230 ppm). MgO varies from 5.9 to 9.2 wt.%. All mafic dykes are enriched in light lanthanide element and show moderate Zr/Nb and high Zr/Y, Nb/Yb, and Ti/V ratios similar to those of average ocean island basalt (OIB)-type magmas. Some dykes that intrude the mylonites show evidence of contamination by continental crust. The composition of the clinopyroxenes of the dykes that intrude the mylonites clearly indicate different and unrelated parental magmas from dykes that intrude the granites. Contents and fractionation of the least and the most incompatible elements suggest low degrees of partial melting (3–5%) of heterogeneous source slightly enriched in incompatible elements in the spinel stability field. The geochemical features of Njimom dykes (in particular the dykes that intrude the granites) are similar to those of Paleozoic and Mesozoic dykes recorded in the southern continental part of the Cameroon Volcanic Line, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of the South Atlantic Ocean.
Yanick Brice Lemdjou, Da Zhang, Jean Pierre Tchouankoué, Jiaxiu Hu, Nicaise Blaise Tchuimegnié Ngongang, Landry Soh Tamehe et 1 autre(s)
Lithos
Jean Pierre Tchouankoué, De Pesquidoux I. Tchato Tchaptchet, Liliane Madeleine Nyassa, Joseline Dieugnou Njuinang, Céline Maffo Feudjou, Clauter Fils Tchato et 2 autre(s)
Journal of African Earth Sciences
Noël-Aimée Keutchafo Kouamo, Depesquidoux Tchato Tchaptchet, Anne Laure Tezanou Ngueguim, Nicole Armelle Simeni Wambo, Jean Pierre Tchouankoué, Ciro Cucciniello
Arabian Journal of Geosciences
Noël-Aimée Keutchafo Kouamo, Depesquidoux Tchato Tchatptchet, Anne Laure Tezanou Ngueguim, Nicole Armelle Simeni Wambo, Jean Pierre Tchouankoué, Ciro Cucciniello
Arabian Journal of Geosciences
Joëlle Flore Tene Djoukam, Charles Nkoumbou, Jean Pierre Tchouankoué, Robert Moritz
Journal of African Earth Sciences
Aurélie Ngamy Kamwa, Jacqueline Numbem Tchakounté, Charles Nkoumbou, Sébastien Owona, Jean Pierre Tchouankoué, Joseph Mvondo Ondoa
Journal of African Earth Sciences
Depesquidoux Tchato Tchaptchet, Nicole Armelle Simeni Wambo, Noël Aimé Keutchafo Kouamo, Jean Pierre Tchouankoué, Ciro Cucciniello
Comptes Rendus Géoscience
The broadly N70°–90°E-trending dykes swarm at Kekem cut across the Paleoproterozoic-to-Achean terranes of West Cameroon remobilized during the Pan-African orogeny. They are picrite basalts and basalts with tholeiitic/transitional affinity, as shown by mineralogical and geochemical data, with variable major and trace element contents, MgO ranges from 7.3 to 12.4 wt.%, Cr from 190 to 411 ppm, Ni from 15 to 234 ppm. All the dykes are light REE enriched with La N /Yb N values of 5.3–8.1, suggesting a co-magmatic origin. They originated from a 2.8% partial melting of a spinel-mantle source with no or little crustal input. The geochemical features of Kekem dykes are similar to those of Paleozoic and Mesozoic dykes recorded in North and Central Africa, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of Central and South Atlantic Oceans.
Xian‐Hua Li, Yi Chen, Jean Pierre Tchouankoué, Chuan‐Zhou Liu, Jiao Li, Xiao‐Xiao Ling et 2 autre(s)
Precambrian Research
Chuan‐Zhou Liu, Liuyang Yang, Xian‐Hua Li, Jean Pierre Tchouankoué
Chemical Geology
Jean Pierre Tchouankoué, Armelle Nicole Simeni Wambo, Noël Aimé Keutchafo Kouamo, Xian‐Hua Li
Acta Geologica Sinica - English Edition
Zsanett Pintér, Levente Patkó, Joëlle Flore Tene Djoukam, István Kovàcs, Jean Pierre Tchouankoué, György Falus et 6 autre(s)
Journal of African Earth Sciences
Jean Pierre Tchouankoué, Nicole Armelle Simeni Wambo, Armand Kagou Dongmo, Xian‐Hua Li
Journal of African Earth Sciences
Jean Pierre Tchouankoué, Arliane Nicole Tetchou Tchekambou
한국토양비료학회 학술발표회 초록집
Suzi Huff Theodoro, Jean Pierre Tchouankoué, António Olímpio Gonçalves, O. H. Leonardos, Julia Harper
Revista Brasileira de Geografia Física
Este trabalho apresenta os resultados de uma pesquisa em desenvolvimento por cientistas brasileiros e de três países africanos (Angola, África do Sul e Camarões). O fio condutor da pesquisa foi a tecnologia da rochagem, que prevê a adição de rochas moídas, que contenham uma ampla variedade de agrominerais, para melhorar os índices de fertilidade dos solos. A partir de interesses comuns - a expansão da pesquisa sobre remineralização dos solos agrícolas e a difusão da tecnologia, o grupo visa principalmente a formalização e consolidação de uma rede de cooperação científica Sul-Sul (afro-brasileira) com ênfase em tecnologias agroecológicas. O incremento dos níveis de fertilidade permite o aumento da produção e contribuí para de segurança alimentar/nutricional e ambiental em meio aos agricultores familiares desses países. Apesar dos diferentes estágios em que se encontram as pesquisas nos quatro países, os resultados já alcançados são muito positivos, pois indicam que pressupostos científicos, socioeconômicos e políticos, até então intransponíveis, podem ser alterados. Palavras-Chave: Rochagem, Agricultores Familiares Afro-brasileiros e Agroecologia The Importance of a Stonemeal Technological Network for Sustainability in Tropical Countries ABSTRACT This paper presents the results of a research being developed by scientists from Brazil and three African countries: Angola, South Africa and Cameroon. The main guide line of the research was stonemeal technology, which provides improvements on the rates of soil fertility by the addition of crushed rocks, which contain a wide variety of Agrominerals. Starting from interests in common – such as the expansion of research on soil remineralization and the diffusion of agricultural technology -, the group aims mainly to formalize and consolidate a South-South (African-Brazil) cooperation network in science with emphasis on agro-ecological technologies. Despite allowing an increased on production levels, the enhance of fertility levels also contributes to the food / nutrition and environmental security among small farmers in those countries. In spite of the different stages of the research is taking place in the four countries, the achieved already are very positive, once they indicate that scientific, socioeconomic and political assumptions hitherto insurmountable, can in fact be changed. Keywords: Stonemeal, Afro-Brazilian Small Farmers and Agroecology
Suzi Huff Theodoro, Jean Pierre Tchouankoué, António Olímpio Gonçalves, O. H. Leonardos, Julia Harper
LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas)
Este trabalho apresenta os resultados de uma pesquisa em desenvolvimento por cientistas brasileiros e de três países africanos (Angola, África do Sul e Camarões). O fio condutor da pesquisa foi a tecnologia da rochagem, que prevê a adição de rochas moídas, que contenham uma ampla variedade de agrominerais, para melhorar os índices de fertilidade dos solos. A partir de interesses comuns - a expansão da pesquisa sobre remineralização dos solos agrícolas e a difusão da tecnologia, o grupo visa principalmente a formalização e consolidação de uma rede de cooperação científica Sul-Sul (afro-brasileira) com ênfase em tecnologias agroecológicas. O incremento dos níveis de fertilidade permite o aumento da produção e contribuí para de segurança alimentar/nutricional e ambiental em meio aos agricultores familiares desses países. Apesar dos diferentes estágios em que se encontram as pesquisas nos quatro países, os resultados já alcançados são muito positivos, pois indicam que pressupostos científicos, socioeconômicos e políticos, até então intransponíveis, podem ser alterados.
The Open Geology Journal
Basaltic dyke swarms in the southern continental part of the Cameroon Volcanic Line (Bangangte, Dschang, Manjo areas) are tholeiitic in composition with 46 to 50 wt.% SiO 2 and have moderate Mg-numbers (53-59), medium TiO 2 contents (1.48-2,05 wt.%), and flat to mildly enriched incompatible trace element patterns. Comparison with trace element patterns of representative Cenozoic basaltic rocks of the Cameroon Volcanic Line (Bana anorogenic complex, Mt. Bambouto, Adamawa Plateau basalts) indicates that these dykes are less enriched in light REE and show different incompatible trace element ratios (La/Yb: 5.7 to 8.6; Zr/Nb: 7.6 to 12.0; Ba/Th: 87.7 to 93.3). The trace element patterns of the dykes and their Sr-and Nd-isotope compositions, however, are similar to those of the pre-Cenozoic volcanic rocks of the Benue Trough in Nigeria. Our data therefore suggest that these dykes represent the magmatic history related to the break-up of Africa and South America and are unrelated to the Tertiary volcanism of the Cameroon Line.
Gautier Njiekak, A. Gerdes, Jean Pierre Tchouankoué, Gernold Zulauf
Striking characteristics of the Pan-African belt of central Africa north of the Congo craton are the large volume of granitoids and crustal-scale shear zones. New structural and geochronological data from this area are provided to put constraints on the tectonic evolution of this segment of the belt and to make further correlations between major shear zones exposed on both sides of the Atlantic Ocean.
Gilbert Kuepouo, H. Sato, Jean Pierre Tchouankoué, Mamoru Murata
Resource Geology
Abstract FeO*‐Al 2 O 3 ‐TiO 2 ‐rich rocks are found associated with transitional tholeiitic lava flows in the Tertiary Bana plutono‐volcanic complex in the continental sector of the Cameroon Line. These peculiar rocks consist principally of iron‐titanium oxides, aluminosilicates and phosphates, and occur as layers 1–3 m thick occupying the upper part of lava flows on the southwest (site 1) and northwest (site 2) sites of the complex. Mineral constituents of the rocks include magnetite, ilmenite, hematite, rutile, corundum, andalusite, sillimanite, cordierite, quartz, plagioclase, alkali feldspar, apatite, Fe‐Mn phosphate, Al phosphate, micas and fine mixtures of sericite and silica. Texturally and compositionally, the rocks can be subdivided into globular type, banded type, and Al‐rich fine‐gained massive type. The first two types consist of dark globule or band enriched in Fe‐Ti oxides and apatite and lighter colored groundmass or bands enriched in aluminosilicates and quartz, respectively. The occurrence of andalusite and sillimanite and the compositional relations of magnetite and ilmenite in the FeO*‐Al 2 O 3 ‐TiO 2 ‐rich rocks suggest temperatures of crystallization in a range of 690–830°C at low pressures. The Bana FeO*‐Al 2 O 3 ‐TiO 2 ‐rich rocks are characterized by low concentrations of SiO 2 (25–54.2 wt%), Na 2 O + K 2 O (0–1%), CaO (0–2%) and MgO (0–0.5%), and high concentrations of FeO* (total iron as FeO, 20–42%), Al 2 O 3 (20–42%), TiO 2 (3–9.2%), and P 2 O 5 (0.26–1.30%). TiO 2 is positively correlated with Al 2 O 3 and inversely correlated with FeO*. The bulk rock compositions cannot be derived from the associated basaltic magma by crystal fractionation or by partial melting of the mantle or lower crustal materials. In ternary diagrams of (Al 2 O 3 )−(CaO + Na 2 O + K 2 O)−(FeO*+ MnO + MgO) and (SiO 2 )−(FeO*)−(Al 2 O 3 ), the compositional field of the rocks is close to that of laterite and is distinct from the common volcanic rocks, suggesting that the rocks are derived from lateritic materials by recrystallization when the materials are heated by the basaltic magmas. A hydrothermal origin is discounted because the rocks contain high‐temperature mineral assemblages and lack sulfide minerals. It is proposed that the FeO*‐Al 2 O 3 ‐TiO 2 ‐rich rocks of the Bana complex were formed by pyrometamorphism of laterite by the heat of basaltic magmas.
Jean Pierre Tchouankoué, Robert Temdjim, C. Tchawoua
Congres Geologique International, Resumes
Rose Noël Ngo Belnoun, Jean Pierre Tchouankoué, Friedrich Koller, Martin Thöni
Phaidra (Universität Wien)
Clémentine Njofang, Jörg Matschullat, Jean Pierre Tchouankoué, A. Amougou
Pakistan Journal of Biological Sciences
This study reports on the distribution of trace elements in the sediments of the Noun River valley. Two groups of trace elements have emerged based on their distribution and geochemical behaviour. The first group shows lower values whereas the second group aligns higher values. Elements like Al and Sr in one side and Zn, Zr in the other present concentrations statistically different from those of the rocks compared to other elements in trace analyzed (Cr, Ni, Ba, Co, Cu, Fe, Mn, V, As and Pb). The trace elements Al, Sr, Zr, Zn and Pb in the sediments of the Noun River show concentrations rather lower than those of the world. The average concentrations in elements C (3.72%), N (0.27%), S (0.05%) and of the ratios C/N (13.77) and N/S (5.29) reflect those resulting from the decomposition of the organic matter which derives from soils with very small concentrations in S. The Noun valley sediments are mostly of primary (quartz, microcline, plagioclase, orthoclase, ilmenite, anatase) and newly formed or secondary (kaolinite, gibbsite, hematite, goethite) minerals. This mineralogy and the overall low concentration of the studied trace elements, with Al, Fe, Ti and Mn as most abundant elements, is consistent with the local geology made up of the basic rocks (basalts, volcanic ash) and of the acid rocks (granites, gneiss). Overall the trace elements concentration and distribution suggest their geogene origin. Yet, this study is a first contribution of its kind towards the development of a baseline geochemical database essential for a sustainable and healthier Noun valley ecosystem.
Gilbert Kuepouo, Jean Pierre Tchouankoué, Takashi NAGAO, H. Sato
Journal of African Earth Sciences
Gautier Njiekak, Wolfgang Dörr, Friedrich Finger, Jean Pierre Tchouankoué, Gernold Zulauf
Jean Pierre Tchouankoué, Umberto G. Cordani, Artur Takashi Onoe
Valderez P. Ferreira, Thyego R. Silva, M.M.C. de Lima, Alcídes N. Sial, Adejardo Francisco da Silva Filho, Charles Henrique Fernandes Sales das Neves et 2 autre(s)
Journal of South American Earth Sciences
Arliane Nicole Tchekambou Tetchou, Josiane Demlabin Sonmo, Armanda Nguiffo, Jean Pierre Tchouankoué, Jean Pierre Nguetnkam, Suzi Huff Theodoro
Asian Journal of Soil Science and Plant Nutrition
This study evaluates the fertilizing potential of micaschist powder in sugarcane farming on ferrallitic soils of the Mbandjok area in Cameroon. These soils are poor in exchangeable cations and assimil able phosphorus, very acidic, with low to moderate CEC. An experimental design, which consisted in a randomized Fischer block, is composed of six replications of five treatments:T0: conventional fertilization (Ureemulticote 39 00, 150 kg ha-1; MAP, 125kg ha-1; KCl,250kg ha-1) T0-M1: T0 + 5 t ha-1of Micaschist powder, T0-M2: T0 + 7 t ha-1of Micaschist powder, NP-M1:N and P supply, conventional dose (no KCl) + 5 t ha-1of Micaschist powder, N-M2: N supply, conventional dose (no P and K) + 7 t ha-1of Micaschist powder. The experiment was carried out between October 2015 and February 2019. During this period, soil samples were collected, sugarcane was planted and monitored with great care in order to determine the parameters indicative of the growth and yield of sugarcane plants. The results indicate an important increase of the sugarcane yield during the three years of experiment, on soils where micaschist powder was added, compared to the control. Concerning the percentage of lift and voids, the T0-M1 treatment had 3% of voids compared to the T0 (9%) treatment which is the reference fertilizer; for Tillers parameter, T0-M1 (338 stems) performs very well during the experiment compared to the T0 (297stems) and for the growth parameter, T0-M1 treatment was good increasing from 182 cm in the first year to 280 cm in the second year. This suggests that micaschist powder has a positive and significant effect on the growth components. For the yield of sugarcane, the best result of tons of sugarcane (TC) was obtained with T0-M1 treatment which increased from 77.15 TC ha-1 in the first year to 86.13TC ha-1 in the third year. The overall results indicate that using micaschist powder as fertilizer can enhance sugar cane yield with a long lasting residual effect of rock powder.
Bovari Syprien Yomeun, Wei Wang, Michele Sandra Kamguia Kamani, Jean Pierre Tchouankoué, Ying-De Jiang, Si‐Fang Huang et 4 autre(s)
Precambrian Research
Bovari Syprien Yomeun, Wei Wang, Jean Pierre Tchouankoué, Michele Sandra Kamguia Kamani, Kevin Igor Azeuda Ndonfack, Si‐Fang Huang et 3 autre(s)
Lithos
Henri Appolinaire Kenzo, Victor Metang, Willy Stephane Segue, Legrand Joseph Tchop, Lucas Mouafo, Diane Marilyn Nkamga Mbakam et 3 autre(s)
Arabian Journal of Geosciences
Fuh Calistus Gentry, Charles Nkoumbou, Jacqueline Tchakounté Numbem, Kundu Okia Mukete, Jean Pierre Tchouankoué
Lithos
De Pesquidoux I. Tchato Tchaptchet, Jacqueline Numbem Tchakounté, Aurélie Kamwa Ngamy, Jean Pierre Tchouankoué, Soumyajit Mukherjee
China Geology
The Central Africa Fold Belt (CAFB) is a collision belt endowed with gold deposits in Eastern Cameroon area mined for about 50 years. However, favorable areas for gold exploration are poorly known. This paper presents (1) the kinematics of the brittle deformation in the Kékem area in the SW portion of the Central Cameroon Shear Zone and (2) constraints gold mineralization events with respect to the collisional evolution of the CAFB. The authors interpret that the conjugate ENE to E and NNW to NW trending lineament corresponds to the synthetic (R) and the antithetic (R’) shears, which accompanied the dextral slip along the NE to ENE striking shear. The latter coincides with the last 570–552 Ma D<sub>3</sub> dextral simple shear-dominated transpression, which is parallel to the Bétaré Oya shear zone hosting gold deposits. Gold mineralizations, which mainly occurred during the last dextral shearing, are disseminated within quartz veins associated to Riedel’s previous structures reactivated due to late collisional activities of the CAFB as brittle deformation. Gold mineralizations occurred mainly during the 570–552 Ma D<sub>3</sub> event. The reactivation, which might be due to dextral simple shear during mylonitzation, plausibly remobilized the early gold deposits hosted in syn-compressional rocks and/or possibly focused deep-sourced fluid mixed with those released by dehydration. Therefore, the Central Cameroon Shear Zone where Kékem is located, and which shows similar petrographical and structural features to those controling Batouri gold district, is a target area for gold exploration in Cameroon.
P. N. N. Nemzoue, N. A. K. Keutchafo, Jean Pierre Tchouankoué
Revista de Engenharia Térmica
Africa is currently experiencing a period of economic growth. Its population is growing rapidly and its economies grow and diversify. To be sustainable, such growth requires a large investment in the energy sector. In the case of Cameroon hydroelectric energy is the main source of electrical power whereas the analysis of the geological point of view shows that Cameroon is unique in west-northern of Africa for its active volcanic line (with the last eruption of Mount Cameroon that last erupted in 1999 and 2000) that is a favorable zone for the production of power from geothermal resources. The Cameroon Volcanic Line (CVL) is 100 km wide linear magmatic megastructure oriented N30°E that extends more than 1500 km from Pagalu Island in the Gulf of Guinea to Lake Chad. Along this active volcanic line, more than one hundred and thirty thermal springs are found with the hottest spring at Woulndé (74°C).The aim of this paper is to evaluate the importance of geothermal energy development in the Cameroon Volcanic Line through a geological investigation of areas (Mt. Cameroon and Adamawa) bearing springs with hottest temperatures. This work is a compilation of the bibliographic analysis find at the same topic of research with a source like an International reviewed article, local documents and a websites research. The absence of commitment and enthusiasm from the government is weakening the sector potentiality to be developed either by private sector investments and also foreign investors. Other applications of geothermal energy in Cameroon are also discussed.
Michele Sandra Kamguia Kamani, Wei Wang, Jean Pierre Tchouankoué, Si‐Fang Huang, Bovari Syprien Yomeun, Er‐Kun Xue et 1 autre(s)
Precambrian Research
Christoph Schmidt, Christian Laag, Jörn Profe, Tom Richter, Jean Pierre Tchouankoué
EGU General Assembly Conference Abstracts
Christoph Schmidt, Jean Pierre Tchouankoué, Peguy Noel Nkouamen Nemzoue, Félicité Ayaba, Siggy Signe Nformidah-Ndah, Emmanuel Nformi Chifu
PLoS ONE
Nyos maar is located in the Cameroon Volcanic Line and generates a multitude of primary and secondary hazards to the local population. For risk assessment and hazard mitigation, the age of the Nyos maar eruption provides some vital information. Since previous dating efforts using a range of techniques resulted in vastly varying eruption ages, we applied thermoluminescence (TL) methods to obtain independent and direct chronological constraints for the time of maar formation. Target minerals were granitic quartz clasts contained in pyroclastic surge deposits. Thermoluminescence plateau results prove that heat and/or pressure during the phreatomagmatic eruption was sufficient to reset the inherited luminescence signal of granitic bedrock quartz. Parallel application of three TL measurement protocols to one of the two samples gave consistent equivalent doses for the quartz ultra-violet emission. Despite the robustness of our dose estimates, the assessment of the dose rate was accompanied by methodological challenges, such as estimation of the original size distribution of quartz grains in the pyroclastic deposits. Considering results from additional laboratory analyses to constrain these uncertainties, we calculate an average maximum TL age of 12.3 ± 1.5 ka for the Nyos maar eruption. Based on these new data, a more solid risk assessment can be envisaged.
Nicole Armelle Wambo Simeni, Depesquidoux Tchaptchet Tchato, Rose Noël Ngo Belnoun, Jean Pierre Tchouankoué, Alembert Alexandre Ganwa
International Journal of Geosciences
The work is a vivid description of the structural relationship between brittle deformation of the Precambrian basement in the southern continental part of the Cameroon Line and intrusive Paleozoic and Mesozoic basalt dykes swarms. A multidisciplinary approach that involves a combination of remote sensing techniques and field studies show that the major trend of brittle structures correspond to well-known regional structures: N70°E (Adamawa Shear Zone), N135°E (upper Benue trend) and N30°E (Cameroon Volcanic Line) corresponding to E-W and N-S directions respectively. Basalt dykes are associated to NE-SW, E-W and NW-SE oriented fractures. An integration of the available information on brittle structures and basalt dykes directions suggest an emplacement of the Mesozoic and Paleozoic basalt dykes structurally controlled by Precambrian structures that were originated through Riedel’s fracture kinematic model with dextral strike-slip Adamawa Shear Zone as the main shear zone during late stage of the Pan-African collision. Spatially, the restriction of the basalt dykes to the corridor of the Adamawa Shear Zone indicate that a rejuvenation of Precambrian faults may very well be the origin of the dykes with possibility that they may have been reworked several times during the Phanerozoic eon.
Christoph Schmidt, Maria Schaarschmidt, Thomas Kolb, Daniel Richter, Jean Pierre Tchouankoué, Ludwig Zöller
EGU General Assembly Conference Abstracts
Christoph Schmidt, Jean Pierre Tchouankoué, Peguy Noel Nkouamen Nemzoue, Félicité Ayaba, Siggy Signe Nformidah-Ndah, Emmanuel Nformi Chifu
Figshare
Nyos maar is located in the Cameroon Volcanic Line and generates a multitude of primary and secondary hazards to the local population. For risk assessment and hazard mitigation, the age of the Nyos maar eruption provides some vital information. Since previous dating efforts using a range of techniques resulted in vastly varying eruption ages, we applied thermoluminescence (TL) methods to obtain independent and direct chronological constraints for the time of maar formation. Target minerals were granitic quartz clasts contained in pyroclastic surge deposits. Thermoluminescence plateau results prove that heat and/or pressure during the phreatomagmatic eruption was sufficient to reset the inherited luminescence signal of granitic bedrock quartz. Parallel application of three TL measurement protocols to one of the two samples gave consistent equivalent doses for the quartz ultra-violet emission. Despite the robustness of our dose estimates, the assessment of the dose rate was accompanied by methodological challenges, such as estimation of the original size distribution of quartz grains in the pyroclastic deposits. Considering results from additional laboratory analyses to constrain these uncertainties, we calculate an average maximum TL age of 12.3 ± 1.5 ka for the Nyos maar eruption. Based on these new data, a more solid risk assessment can be envisaged.
Xian‐Hua Li, Yi Chen, Jiao Li, Chuan Yang, Xiao‐Xiao Ling, Jean Pierre Tchouankoué
Precambrian Research
Jean Pierre Tchouankoué, Xian‐Hua Li, Rose Noël Ngo Belnoun, Lucas Mouafo, Valderez P. Ferreira
Journal of African Earth Sciences
Jean Pierre Tchouankoué, Yannick Lemdjou, F. C. TCHATO
Acta Geologica Sinica - English Edition
E. Kemayou Tchamako, R.V. Tsinkou Fotsing, Jean Pierre Tchouankoué, Jules Rémy Ndam Ngoupayou, Benjamin Ngounou Ngatcha, Nancy W. Hinman
Procedia Earth and Planetary Science
The Ngam and Mou Rivers belong to the river system of the central part of the Cameroon Volcanic Line. The Ngam River watershed comprises 51 Ma old basalts, while the Mou River watershed comprises younger, < 5 Ma pyroclastic basalts. The physico-chemical characteristics of water samples from both watersheds indicated pH between 4.2 and 8.2, and 4.2 to 7.5, and very low mineralization between 11 and 246 μS/cm and 45 to 165 μS/cm, respectively, for the Ngam River and the Mou River. Chemical data showed that waters from old, highly weathered plateau basalts (Ngam River watershed) were dominated by calcium and sodium (signatures of feldpars from syenites and orthogneisses), while waters in the Mou River watershed were dominated by magnesium (signature of olivines and pyroxenes from basalts). Mineralizations in the two watersheds are thus primarily controlled by lithology rather than anthropic activities. These results are promising for identifying potential potable water resources in these areas.
Jean Pierre Tchouankoué, D. G. Nkouathio, C. Njofang, Éder de Souza Martins, S. H. Theodoro
Clémentine Njofang, Jörg Matschullat, Amougou Akoa, Jean Pierre Tchouankoué, Hermann Heilmeier
Environmental Geology
Merline Laure Djouka-Fonkwé, Bernhard Schulz, Ulrich Schüssler, Jean Pierre Tchouankoué, Charles Nzolang
Journal of African Earth Sciences
Gautier Njiekak, Wolfgang Dörr, Jean Pierre Tchouankoué, Gernold Zulauf
Lithos
Jean Pierre Tchouankoué, Umberto G. Cordani, Artur Takashi Onoe
Boletim de Resumos
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