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Geochemical and Petrological Insights into the Neoproterozoic Moumba Metabasites: Implications for Crustal Processes in the West Congo Belt (Republic of Congo)

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Journal of Geoscience and Environment Protection 2024年第2期12卷 1-29页

作者： Ulrich Verne Matiaba-Bazika Nelson Lekeba Makamba Vicky Tendresse Télange Bouénitéla Nicy Carmelle Bazebizonza Tchiguina Timothée Miyouna florent boudzoumou Laboratory of Geosciences Faculty of Sciences and Technics Marien NGOUABI University Brazzaville Republic of Congo National Institute for Research in Exact and Natural Sciences (IRSEN) Brazzaville Republic of Congo Geographid Research and Cartographic Production Center (CERGEC) Brazzaville Republic of Congo

The West Congo Belt contains in its rocks of Neoproterozoic age from Nemba complex outcropping in the Moumba River. This West Congo belt is made up of a crustal segment of the Arcuaï-West Congo orogen which extends from southwest Gabon to the northeast of Angola. This study aims to constrain the geochemical signature Nemba complex of West Congo belt from the petrograhic and geochemical study on the whole rock. The petrographic data from this study show the Moumba metabasites are made up of amphibolites, metagabbros, epidotites and greenschists interstratified in the Eburnean metasediments and affected by mesozonal to epizonal metamorphism characterized by the retromorphosis of intermediate amphibolite facies minerals into greenschist facies. Whole-rock geochemical data indicate that these metabasites are continental flood basalts (CFB) of basic nature and transitional affinity emplaced in intraplate context. These continental flood basalts are generated from magma originating from a significantly enriched shallow mantle plume and this magma then contaminated by the continental crust during their ascent. The reconstruction of tectonic signature suggests that West Congo belt would result from closure of an ocean basin with subduction phenomena. This collision would be marked by the establishment of ophiolite complex. We show that this model is incompatible with the CFB nature of metabasites and the orogenic evolution of Neoproterozoic. It does not seem that we can evoke a genetic link with a subduction of oceanic crust, because the paleogeography of Neoproterozoic (Rodinia) is marked by intracontinental rifts linked to opening of Rodinia. We therefore suggest the non-existence of ophiolitic complex in western Congo belt and reject the collisional model published by certain authors. We confirm the currently available intracontinental orogen model.

关键词： Mayombe Metabasites Moumba Mantle Plume Continental Rifting Basalts Flood Continental

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Petrology and Geodynamic Context of Metabasic Rocks of Nemba Complex in the West Congo Fold Belt (Republic of Congo)

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International Journal of Geosciences 2018年第1期9卷 1-18页

作者： Louis Marie Joachim Djama Ulrich Verne Matiaba Bazika florent boudzoumou Kinga Mouzeo Université Marien Ngouabi Département de Géologie Brazzaville Congo Institut de Recherches en Sciences Exactes et Naturelles (IRSEN) Avenue de l’Auberge de Gascogne Cité Scientifique (Ex-ORSTOM) Chateau d’Eau Brazzaville Congo

The West Congo belt contains Paleoproterozoic and Neoproterozoic Units which are deformed during Panafrican event. The Neoproterozoic Unit contains rift and post rift deposits. The rift formation is made of metabasite, volcanic and volcano-sedimentary rocks. The metabasite constitutes the Nemba Complex which is considered put into place in a continental or oceanic context. Samples from Nemba Complex collected along the “Congo ocean railway realignment” are analyzed. Major elements indicate a low potassic subalkaline affinity of the samples. Classification diagrams based of major elements shows that the rocks are a tholeiitic serie constituted of andesitic basalts, sub-alkaline andesitic basalts and a sub-alkaline to alkaline basalts. Some samples with a calc-alkaline signature indicate a crustal contamination. The traces elements plots indicate that the rocks are the MORB. The spectrum of multi-elements is characteristic of continental rocks with a lithospheric origin. This is an agreement with many works on the Nemba Complex and the alkali plutons and acid volcanic rocks associated which attribute there a rift context.

关键词： West Congo Neoproterozoic Tholeiite Andesitic Basalts Basalts MORB Continental Rocks

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Geochemistry and Petrogenesis of Basic and Ultrabasic Rocks Elogo Complex in Ivindo Archean Block (Congo Craton): Geodynamic Implications

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Open Journal of Geology 2023年第2期13卷 107-135页

作者： Nelson Lekeba Makamba Vicky Tendresse Télange Bouenitela Ulrich Verne Matiaba-Bazika florent boudzoumou Geodynamics Laboratory Faculty of Science and Technology Marien Ngouabi University Brazzaville Republic of the Congo Department of Geosciences National Institute for Research in Exact and Natural Sciences Brazzaville Republic of the Congo

The Elogo complex is a greenstone belt portion located on the Eastern edge of the Archean Congo craton at the junction with the Paleoproterozoic to Neoproterozoic Sembe Ouesso basin. This study was carried out on this complex to determine the context of the placement of basaltic rocks. Metaluminous tholeiitic basalts (basic and ultrabasic), calc-alkaline basalts, andesitic basalts, and peraluminous calc-alkaline dacites represent greenstones. Tholeiitic and calc-alkaline basalts come from deep enriched and depleted mantle sources, including garnet in fusion residues [Al2O3/TiO2 > 16 (16.5 to 35.12) and in some samples between 12.45 to 14.48;CaO/Al2O3 1 (1.04 to 1.35) in ten samples and (Gb/Yb)PM > 1]. The calc-alkaline dacites come from a shallow depleted mantle source [Al2O3/TiO2 > 16;CaO/Al2O3 1]. Tholeiitic and calc-alkaline basalts have a negative Rb, Ba, Ce, and Nb anomaly without negative Ti anomaly, positive Ta, Pb anomalies, and a lack of significant REE [(La/Yb)n = 0.36 to 0.97 and 1 to 2.15;(Ce/Yb)n = 0.27 to 0.96 and 1.04 to 1.72, respectively] fractionation. High Nb/Th (2 to 10) and Nb/U (1.82 to 26) ratios and low La/Ta (5 to 27) ratios are characteristic of divergent margin magmatic sources. Tholeiitic and calc-alkaline basalts correspond to an extensive back-arc basin-type tectonic setting. Calc-alkaline andesitic basalts and dacites show positive Ba, U, Th, K, La, Ce, Pb, and Li anomalies and negative Nb, Ta, and Ti anomalies reflecting crustal contamination and hydrothermal alteration in a compressive tectonic context as a volcanic arc in a subduction regime marking the interruption of the meso-neoarchean Elogo’s opening. Elogo’s opening and closing are probably associated with the emplacement of the greenstone of the meso-neoarchean Gabon Belinga group and the relics of the Mesoarchean greenstones of the Cameroun Ntem complex.

关键词： Elogo Greenstone Archean Tholeiitic Andesitic Basalts Dacites Magma Source

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New Computerized Method for the Geochemical Classification of Precambrian Carbonate Rocks: Case of a Set of African Cap Carbonates

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International Journal of Geosciences 2013年第10期4卷 37-49页

作者： Hélène Miche Roland Simler Pascal Affaton Olivia Mickala florent boudzoumou Michel Mbina Aix-Marseille Université CNRS IRD CEREGE UM 34 Aix en Provence France Département de Géologie Faculté des Sciences et Techniques Université Marien Ngouabi de Brazzaville Brazzaville République du Congo Département de Géologie Université des Sciences et Techniques de Masuku Franceville Gabon Université d’Avignon et des pays du Vaucluse INRA EMMAH UMR 1114 LHA Avignon France

Post-sedimentary transformations have masked or completely obliterated the structures and textures of Precambrian carbonate rocks. Therefore, methods of classification of the carbonate rocks founded on the observation of primary structures or textural characteristics are ill-adapted. Consequently, only certain geochemical classification methods allow us to distinguish the various rock-types in the case of Neoproterozoic carbonates. After presenting the most suitable geochemical classifications, we propose a new classification into 14 groups based on a regular ternary diagram with computerized data input. For each sample of carbonate rock, analysis of calcium and magnesium contents allows us to calculate the input data for our diagram i.e. the percentages of Calcite, Dolomite and Insoluble Residue. To automate the application of this diagram, input parameters are created in a descriptive file “***” using an option called “Ternaires” in the “Diagrammes” software developed by Roland Simler. Thirty cap carbonates of Africa are used to validate this new method.

关键词： Carbonate Rock Cap Carbonate Ternary Diagram Software Calcite Dolomite

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Petrology and Geochemistry of Loukounga Metabasites Rocks: Constraining the Geodynamic Context of Neoproterozoic Nemba Complex in the Mayombe Belt

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Open Journal of Geology 2022年第11期12卷 919-946页

作者： Ulrich Verne Matiaba Bazika Vicky Tendresse Télange Bouénitéla Nelson Makamba Lekeba florent boudzoumou Laboratoire de géodynamique Faculté des Sciences et Techniques Université Marien Ngouabi Brazzaville Congo Département des Géosciences Institut National de Recherches en Sciences Exacts et Naturelles Brazzaville Congo

This study focuses on the metabasite rocks of the Nemba Complex of the Mayombe belt, an African segment of Araçuaï-West Congo Orogen (A-WCO) extending from the southwest of Gabon to the northwest of Angola. These metabasite rocks outcrops are in southwestern Congo along the Loukounga river. The Nemba complex is of Neoproterozoic age and represents the lower part of the west congolian Supergroup. The objective of this study is to constrain the geodynamic context of the Nemba complex from the petrology and geochemistry of the metabasites sampled in the Loukounga River. The observed rocks are composed of amphibolites, metagabbros, epidotites and greenschists and are affected by folding accompanied by flux schistosity and crenulation schistosity. Geochemical analyzes show that the rocks have a basic to ultrabasic chemical composition with SiO2 contents between 41.85% and 58.23%. The geochemical composition of the major and traces elements shows that the rocks are basalts, basaltic andesites and andesites. The magma shows enrichment in LREE, LILE and depletion in HREE and HFSE. The multielement spectra show negative anomalies in Nb-Ta, Ti and a relatively low Nb/La ratio which characterize a lithospheric source contaminated by continental crust. Traces elements discrimination plots show that Loukounga metabasites are emplaced in intraplate geodynamic context like that associated with the basalts of the trap-types continental shelves and are possibly derived from mantle plumes contemporaneous with or slightly prior to magmatism.

关键词： Nemba Complex Mayombe Loukounga Greenstone Geodynamic Context Mantle Plumes

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Comparative Study of Slope Soils Analysis by Using Limit Equilibrium and Finite Element Methods

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International Journal of Geosciences 2022年第12期13卷 1089-1102页

作者： Kempena Adolphe Watha Ndoudy Noël Obami Ondon Harmel Mbilou Urbain Gampio Antonio Olimpio Gonçalves Rafael Guardado Lacaba boudzoumou florent Department of Geology Faculty of Sciences and Techniques Marien Ngouabi University Brazzaville Republic of Congo Mechanical Energy and Engineering Laboratory Higher National Polytechnic School Marien Ngouabi University Brazzaville Republic of Congo Department of Geology Faculty of Sciences Agostinho Neto University Luanda Angola Department of Geology Faculty of Mines and Geology Higher Institute of Mines and Metallurgy Moa Cuba

The slope soil analysis remains a corporate concern in construction activities. Because of its significance, the evaluation of slope soil stability has called widespread attention to several researchers all over the world. Many methods have been technologically advanced to evaluate the stability of slopes soils founded on distinct expectations and circumstances. Every method has specific benefits and limits. This work makes a comparison among safety factors and slip surfaces of slopes soils based on using Limit Equilibrium and Finite Element methods. Therefore, SLIDE 6.0 and PLAXIS 8.0 software were used for Limit Equilibrium and Finite Element methods, respectively. The computations of safety factors were performed for diverse shapes of slopes including different types of soils. Failure surfaces and values of safety factors obtained were compared for both methods used. It was noticed that the safety factors obtained from Limit Equilibrium methods were larger than of which is obtained by the finite element code. Moreover, an important change is noticed between the slip surfaces obtained by using both approaches.

关键词： Slopes Soils Slip Surface Limit Equilibrium Finite Element Factor of Safety

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Characterization of Gold Bearing Placers and Associated Minerals in the Elogo Region (North-West Congo Republic)

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Open Journal of Geology 2023年第5期13卷 287-305页

作者： Noël Watha-Ndoudy Prince Espoire Wamene Okoumel Timothée Miyouna Renaud Hermann Assouka Mpika Eddy Guembou Massala Guichel Souaty Mibantsa Kester Mayenga Joseph Victor Hell Boniface Kankeu florent boudzoumou Laboratory of Geosciences Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo National Institute of Forestry Research (IRF) Brazzaville Congo Gold Mines and Quarries of Congo MAC-CONGO Brazzaville Congo Institute of Geological and Mining Research (IRGM) Yaoundé Cameroun

The Elogo region has been subjected to craft industry and semi-industrial mining for gold-bearing placers, since the colonial times. It is actually undergoing an intensive exploration for a primary gold deposit. The goal of this study is to contribute to the exploration of the primary gold deposit in the Elogo Region (North-West of Congo Republic). The methodology consisted of characterization of placers deposits by their lithology, mineralogy and the gold grains shape, in order to constrain the source of gold with the respect to the local geology. The results obtained show that alluviums are polygenic and yields seventeen mineral species composed of zircon, olivine, magnetite, ilmenite, gold, garnet, rutile, coltan, cassiterite, monazite, apatite, amphibole, tourmaline, pyrite, limonite, chromite, and amphibole. The morphoscopy of gold grain shows single grains and grains with quartz inclusions that suggest their relationship with quartz veins. The gold grains are flattened, sub-flattened, and rounded. The northern region of Elogo characterized by a dominance of coarser quartz-included gold grains indicates a proximal proparte origin (less than 50 m), while the southern region, showing less coarse and more evolved grains with choc marks, appears to be associated with a distal pro-parte origin (more than 300 m). The multivariate statistical analysis shows seven classes of samples corresponding to the mineralogical paragenesis suggesting various sources, consisting of high-grade metamorphic, granitoids, pegmatites, basic and ultrabasic rocks, and BIFs that provided minerals to the placers. Gold mainly comes from hydrothermal quartz veins and probably from the peptization of gold from the weathering of sulfides occurring in the BIF. In the Elogo region, gold exploration for primary deposits should look for and follow the hydrothermal system developed in this region. Chemical analysis for the gold grains and associated minerals is necessary to better guide the proposed

关键词： Auriferous Placers Associated Minerals Correspondence Factor Analysis Principal Component Analysis Elogo Gold Exploration

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Data-driven analysis of chemicals,proteins and pathways associated with peanut allergy:from molecular networking to biological interpretation

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Food Science and Human Wellness 2024年第3期13卷 1322-1335页

作者： Emmanuel Kemmler Julian Braun florent Fauchère Sabine Dölle-Bierke Kirsten Beyer Robert Preissner Margitta Worm Priyanka Banerjee Institute for Physiology Charité-University Medicine BerlinBerlin 10115Germany Member of the KFO339 FOOD@Berlin 10115Germany Si-M/“Der Simulierte Mensch”a science framework of Technische Universität Berlin and Charité-Universitätsmedizin Berlin Berlin 10115Germany Charité-Universitätsmedizin Berlin corporate member of Freie Universität BerlinHumboldt-Universität zu Berlinand Berlin Institute of HealthBerlin 10115Germany Division of Allergy and Immunology Department of DermatologyVenerology and AllergyCharité-Universitätsmedizin Berlincorporate member of Freie Universität Berlin and Humboldt-Universität zu BerlinBerlin 10115Germany Pediatrics Campus VirchowCharité-University Medicine BerlinBerlin 10115Germany

Peanut allergy is majorly related to severe food induced allergic *** food including cow's milk,hen's eggs,soy,wheat,peanuts,tree nuts(walnuts,hazelnuts,almonds,cashews,pecans and pistachios),fish and shellfish are responsible for more than 90%of food ***,we provide promising insights using a large-scale data-driven analysis,comparing the mechanistic feature and biological relevance of different ingredients presents in peanuts,tree nuts(walnuts,almonds,cashews,pecans and pistachios)and ***,we have analysed the chemical compositions of peanuts in different processed form raw,boiled and *** the data-driven approach we are able to generate new hypotheses to explain why nuclear receptors like the peroxisome proliferator-activated receptors(PPARs)and its isoform and their interaction with dietary lipids may have significant effect on allergic *** results obtained from this study will direct future experimeantal and clinical studies to understand the role of dietary lipids and PPARisoforms to exert pro-inflammatory or anti-inflammatory functions on cells of the innate immunity and influence antigen presentation to the cells of the adaptive immunity.

关键词： Allergy informatics Knowledge-graph Data analysis Food allergy Peroxisome proliferator-activated receptors Fatty acids

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Production and achievements of Sesamum indicum industry in the world:Past and current state

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Oil Crop Science 2024年第3期9卷 187-197页

作者： Gazali B.T.A.Sanni Vincent Ezin Ifagbémi Bienvenue Chabi Antoine Abel Missihoun Quenum florent Zangui Hamissou Mareme Niang Adam Ahanchede Department of Crop Production Faculty of Agricultural SciencesUniversity of Abomey-Calavi01BP 526CotonouBenin Laboratory of Valorization and Quality Management of Food Bio-Ingredients Faculty of Agricultural SciencesUniversity of Abomey-Calavi01BP 526CotonouBenin Laboratory of Genetic and Biotechnology Faculty of Sciences and TechnologyUniversity of Abomey-CalaviBP 526CotonouBenin Department of Vegetal Production Abdou Moumouni UniversityFaculty of AgronomyBP:10960Niamey-Niger ISRA-CERAAS Thies-EscaleThiesBP 3320Senegal

Sesame production is important in agriculture,food industry,and the crop diversity due to its rich nutritional profile and health *** its significant value,sesame is still an orphan crop that has received little scientific attention,resulting in low yield compared to other major oilseed *** review offers a comprehensive overview of the present state of production,knowledge,and research advancements concerning Sesamum indicum on a global *** FAOSTAT database was extensively used to examine the global trends from 1961 to *** the past 60 years,global sesame production has substantially increased,with Asia and Africa being the primary *** integration of omics technologies and biotechnological interventions has revolutionized our understanding of the genetic basis of sesame,enhanced productivity,invigorated stress resilience,and improved seed ***-throughput sequencing methods such as RNA-seq,RAD-seq,SLAF-seq,and GBS technology are used in various studies,linkage mapping,and identification of trait-associated *** linkage maps,and multi-omics studies such as genomics,proteomics,transcriptomics,and metabolomics have been employed in sesame research for gene and QTL *** and metabolic pathways related to oil content,yield,and stress tolerance were *** and QTLs related to yield and its components,drought,salt,and osmotic stress tolerance were *** genes associated with capsule shattering and seed shattering were recently *** more achievement in sesame,it is important to enhance sesame production efficiency through mechanization,advanced agricultural practices,and knowledge dissemination to *** and multi-omics integration should be particularly *** advancements in sesame production present a significant and promising opportunity for farmers,governments,and stakeholders in the agricultural sector.

关键词： Sesamum indicum Oil yield Genetic markers Sesame industry Omics improvement

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Comparative Study of Early Neonatal Complications between the First and Second Twin during Twin Vaginal Deliveries at the Yaounde Gynaeco-Obstetric and Pediatric Hospital, and the Yaounde Central Hospital

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Open Journal of Obstetrics and Gynecology 2024年第3期14卷 381-392页

作者： florent Ymele Fouelifack Felicite Nguefack Patricia Bashir Kadidja Roosvelt Dongmo Tiodjou Jeanne Hortence Fouedjio Pascal Foumane Higher Institute of Medical Technology of Nkolondom Yaounde Cameroon Obstetrics and Gynaecology Unit of Yaounde Central Hospital Yaounde Cameroon Associative Group for Research Education and Health La Falaise “GARES-Falaise” Dschang Cameroon Obstetrics and Gynaecology Unit of the Yaounde Gynaeco-Obstetrics and Pediatric Hospital Yaounde Cameroon Faculty of Medicine and Biomedical Sciences University of Yaounde I Yaounde Cameroon

Introduction: Twin birth is the expulsion of two fetuses and their appendages out of the woman’s reproductive tract. It’s a high-risk delivery because of the high frequency of maternal, fetal and neonatal complications. Few studies exist on the comparative prognoses of twins. Our objective was to compare early neonatal complications in first and second twins. Methods: We carried out a cross-sectional prospective study from January 2 to April 30, 2020 (4 months) at the Yaounde Gynaeco-Obstetric and Pediatric Hospital, and the Yaounde Central Hospital. Data collected were analyzed using IBM SPSS version 23. Descriptive statistics were done in frequencies and percentages, means and standard deviations. Paired-sample student's t-test were used to compare means. McNemar’s Chi-square and Ficher’s exact tests were used to compare proportions. Statistical significance was set at p-values less than 0.05. Results: Of a total of 2183 deliveries during the study period, 43 (1.96%) were twin vaginal deliveries. Among the 43 women, 41 consented to have their newborns participate in the study. Overall, APGAR scores were better for the first twins at the first (p = 0.004) and fifth (p = 0.031) minutes than for the second twins. Although both twins had complications and that there were 4 neonatal deads of the second twin, there was no relationship between studied complications and the rank of the twin (p = 0.310). Conclusion: As the APGAR score seemed to be better for first twins, clinicians should pay more attention during twin births, in order to improve the prognosis of the second twin.

关键词： Comparison Vaginal Birth Rank of Twin Early Neonatal Complications

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