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Miocene Foraminifera Biostratigraphy and Interpretation North Deep Sea Block of the Congolese Atlantic Basin

Open Journal of Geology 2021年第7期11卷 253-274页

作者： Nehl Dorland Kobawila hilaire elenga Louis Richard Ngatse Department of Geology Faculty of Science and Technology Marien Ngouabi University Brazzaville Republic of Congo Geological and Mining Research Center Brazzaville Republic of Congo National Petroleum Society of the Congo Brazzaville Republic of Congo

This work is the subject of the biostratigraphic and palaeoenvironmental study of the North Deep Sea area of the Congolese Miocene Atlantic Basin. This study is made from samples of lateral cores, drill cuttings and electrical logs. Lithology generally exhibits an irregular alternation of weakly indurated grey clay, light grey siltstones, and whitish, quartzitic sand, medium to coarse-grained, sub-angular to rounded. The presence of glaucony indicates that sediments have been deposited in a calm and reducing environment. The entire formation is fossiliferous. Micropaleontological analysis revealed 120 species of foraminifera including 98 planktonic (81.67%) and 22 benthic (18.33%) species used for biozonation, dating and interpretation of palaeoenvironments. Similarly, the bio-events of plankton foraminiferal, characterized by the level of the first appearance of certain species, have made it possible to identify fifteen biozones (Globorotalia plesiotumida, Globorotalia merotumida, Globorotalia acostaensis, Globorotalia menardii, Globigerina nepenthes, Globorotalia siakensis, Globorotalia fohsi, Globorotalia praefohsi, Globorotalia peripheroacuta, Globorotalia peripheroronda, Praeorbulina sicana, Catapsydrax dissimilis, Globigerinatella insueta, Paragloborotalia kugleri and Globorotalia kugleri) corresponding to age between Aquitanian and Lower Pliocene. Biofacies analysis of foraminifera has identified palaeoenvironments that vary from open marine environments, bathyal to abyssal.

关键词： Biostratigraphy Foraminifera Palaeoenvironments Miocene Congolese Atlantic Basin

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Sedimentary Dynamics of the Sands of the Cover Formation in the Batéké Plateaus (Republic of Congo): Paleoenvironmental Implications

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Journal of Geoscience and Environment Protection 2024年第10期12卷 321-346页

作者： Otongo Judicaël Ngakosso Ngolo Jude Nogelvi elenga hilaire Geosciences Laboratory Doctoral Training Department Faculty of Science and Technology Marien Ngouabi University Brazzaville Republic of Congo Natural Sciences Program Higher Normal School Marien Ngouabi University Brazzaville Republic of Congo Geological and Mining Research Center Brazzaville Republic of Congo

The depositional environment of the sands of the cover formation is discussed. This study aims to determine the paleoenvironments of deposition of the sands of the cover formation in the Batéké Plateaus by studying sedimentary dynamics based on the description of lithological facies in the field and granulometric analyses in the laboratory. In the field, six (6) lithostratigraphic logs were surveyed and 42 sand samples were taken for laboratory analysis. In the laboratory, the samples underwent granulometric, sieving and sedimentometry analyses, after washing with running water using a 63 µm sieve. These analyses made it possible to determine the granulometric classes of the samples. The sieving results allowed to determine the granulometric parameters (mean, standard deviation, mode, median, skewness, flattening or kurtosis) using the method of moments with the software “Gradistat V.8”, granulometric parameters with which the granulometric facies, the mode of transport and the deposition environment were determined using the diagrams. Morphoscopy made it possible to determine the form and aspect of the surface of the quartz grains constituting these sands. Granulometric analyses show that these silty-clay or clayey-silty sands are fine sands and rarely medium sands, moderately to well sorted and rarely well sorted. The dominant granulometric facies is hyperbolic (sigmoid), with parabolic facies being rare. The primary mode of transport of these sands is saltation, which dominates rolling. The dispersion of points in the diagrams shows that these sands originate from two depositional environments: aeolian and fluvial. Morphoscopic analysis reveals the presence of clean rounded matt grains (RM), dirty rounded matt grains (RS), shiny blunt grains (EL) and shiny rounded grains (RL). The rounded matt grains exhibit several impact marks. The presence of dirty rounded grains with a ferruginous cement on their surface indicates that these sands have been reworked. These sa

关键词： Sands Lithology Granulometric Analyzes Morphoscopy Deposit Environment Batéké Plateaus

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Effect of Incorporation of Chips and Wood Dust Mahogany on Mechanical and Acoustic Behavior of Brick Clay

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Journal of Building Construction and Planning Research 2014年第3期2卷 198-208页

作者： Gilbert Ganga Timothee Nsongo hilaire elenga Bernard Mabiala Thomas Tamo Tatsiete Nzonzolo Ecole Nationale Supérieure Polytechnique (ENSP) Université Marien Ngouabi Brazzaville Congo Faculté des Sciences et Techniques Université Marien Ngouabi Brazzaville Congo Ecole Nationale Supérieure Polytechnique (ENSP) Université de Yaoundé I Yaoundé Cameroun

An experimental study was carried out on bricks using local materials in order to take into account the waste wood management to protect the environment and to reduce the cost of the habitat. Chips and sawdust were built-in clay bricks in order to study their influence on the compressive strength, Young’s modulus and the speed for soundproofing. Testings in compressive strength were made on the parallelepiped clay bricks, stabilized with different percentages of cement, with incorporation to various percentages of sawdust or wood chips (Mahogany), using a universal press. Young’s modulus was measured from the speed of sound by the ultrasonic method. The results obtained show that the incorporation of mahogany tree chips in the stabilized brick at 8% of cement, does not have much effect on the compressive strength. It was found that the incorporation of chips or sawdust on the clay brick, does not improve the compressive strength. The Young’s modulus decreases with increasing content of sawdust and practically remains constant regardless of the content of chips at 4% and 6% of cement. The clay brick mixed with 8% of mahogany sawdust can be an acoustic barrier.

关键词： Effect of Incorporation of Chips and Wood Dust Mahogany on Mechanical and Acoustic Behavior of Brick Clay

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Characterization and Application of the Makoua Clay in the Chemical and Bacteriological Depollution of Gutter and Well Waters of Brazzaville

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Materials Sciences and Applications 2021年第6期12卷 263-275页

作者： Ferland Ngoro-elenga Atipo Itoua Ngopoh hilaire elenga Jean-Romuald Mambou Jude Novelgi Ngakosso Ngolo Timothée Nsongo Faculté des Sciences et Techniques Université Marien Ngouabi Brazzaville Congo Groupe de Recherches sur les Propriétés Physico-chimiques et Minéralogiques des Matériaux Université Marien Ngouabi Brazzaville Congo Centre de Recherches Géologiques et Minières Brazzaville Congo

In this work, the authors made aquatic filters according to the formulation “clay stabilized at 4% of cement mixed with 4% of kambala sawdust and 10% of white sand” then heated to 1050°C to decontaminate the waters of gutters and wells. The authors carried out geotechnical, geochemical, thermal, infrared spectroscopy, and scanning electron microscopy that analyzed the clay material. Geotechnical analyzes have shown that this material is made up of 22% thin sand, 22% of silt, and 56% of clay with 26 plasticity index. The geochemical analysis showed the presence of trace elements shared out as follows: 3% of alkaline metals, 24% of alkaline earth metals, 46% of transition metals, 10% of metal, 16% of lanthanides, 1% of actinides. The most abundant trace elements are barium (19%), vanadium (12%), chromium (11%) and zinc (9%). The thermal and microscopic analyzes revealed the kaolinitic nature of materials. The chemical depollution studies have shown elimination yields of 50% - 52.38% of sulphates;77.33% - 85.19% of phosphates;34.85% - 88.49% nitrates;91.3 - 100 of sulphides;The removal of bacteriological pollution are 92.8% - 98% of total germs;94% - 97% of total coliform and 95% - 98% of E. coli.

关键词： Clay Characterization Chemical Depollution Bacteriological Depollution Gutter and Well Water Makoua

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Sedimentological Study of Alluvial Deposits on the Congolese Coast: Highlighting the Erosive Character of the Holocene Wet Climatic Phases

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Open Journal of Geology 2023年第1期13卷 1-22页

作者： hilaire elenga Nehl Dorland Kobawila Dieudonne Maurice Malounguila-Nganga Malanda Nimy Edmond Nicaise Giresse Pierre Geosciences Laboratory Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Geological and Mining Research Center (CRGM) Brazzaville Congo Center for Training and Research on Mediterranean Environments (CEFREM) University via Dominitia Perpignan France

A granulometric, mineralogical, morphoscopic and exoscopic study and Rock-Eval analysis carried out on samples taken in the Loango Bay and at Kivesso on the Congolese coast have made it possible to highlight the highly erosive character of the well-documented wet phases ca 9000 - 3000 years B.P. and ca 320 B.P. in the sub-region. Supported by carbon-14 dating, total organic carbon analyses highlight two major phases of peat deposit emplacement. The first, ca. 7000 years B.P., corresponds to the beginning of the deposition of the yellow formation in the entire Loango Bay;the second, ca. 320 years B.P., is contemporary with the deposition of peat in the Kivesso sector. The granulometric analysis of the sediments shows that they are essentially sandy-clay and very poor in silt, alternating with beds of silty clay sometimes rich in organic matter. These sands have a predominant mode of 0.200 mm and an average varying between 0.150 and 0.300 mm. They constitute the flood phase of the carrier current. They are associated with a population of mode 0.125 mm sometimes 0.050 mm with an average varying between 0.100 mm and 0.126 mm which corresponds to the settling phase. Morphoscopic examination showed several varieties of quartz that argue for a source of supply close to the depositional sites.

关键词： Holocene Paleoclimates Paleoenvironments Loango Bay Sedimentology

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Sedimentology and Mineralogy of Surface Formations of the Mossendjo Area (Republic of Congo): Paleoenvironmental and Paleoclimatic Implications

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Open Journal of Geology 2021年第10期11卷 471-493页

作者： Jude Nogelvi Ngakosso Ngolo hilaire elenga Mambou Jean Romuald Malounguila Ganga Dieudonné Malanda Edmond Laboratory of Geosciences Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo Geological and Mineral Research Center (CRGM) Brazzaville Congo

Studies undertaken at several sites in the Congolese basin and in the Chaillu massif are helping to reinterpret the sedimentological formations known as cover formations, which are widely exposed in Central Africa. This article presents the results of granulometric, morphoscopic, mineralogical and chemical analyzes obtained at three sites in the Chaillu. Gronulometric analysis indicates that the sands at the three sites are rated medium to high. The cumulative curves are essentially sigmoidal with regular and spreading slopes. This facies indicates that the deposition took place due to a banal and moderate variation in the competence of the carrier current. The morphoscopy of the quartz grains shows that they are mainly angular and shiny. These data reflect a relatively close source and transport by water. The synthesis of lithological, granulometric, petrographic and geochemical analyzes allowed us to highlight three episodes of deposits in the Mossendjo area: the first is characterized by a channel-type fluvial system marked by deposits from the hospital borehole and from the station;the second, which is alluvial, corresponds to the clogging of the channel. These two alluvial phases are overcome by a third, fluvial, channel-type episode, the end of which is marked by the establishment of the yellow formation. The vertical and lateral organization at the outcrop of this yellow formation has the same characteristics as those described earlier and in the sub-region where it was attributed to the wind-generated cover formation. This study thus highlights the existence of a wet phase during which two fluvial systems of non-contemporary channel types developed which overlap.

关键词： Sedimentology Fluvial System Paleoenvironment Mossendjo Congo

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Influence of Sugarcane Bagasse Fibers on the Mechanical Strength and Porosity of Concrete Made with Forspak 42.5 N Cement in the Republic of Congo

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Advances in Materials Physics and Chemistry 2024年第11期14卷 249-263页

作者： Christ Ariel Malanda Ceti Alain Second Dzabana Honguelet Ferland Ngoro-elenga Timothée Nsongo Abel Dominique Eboungabeka hilaire elenga Nice Ngouallat Mfoutou National Higher Polytechnic School Marien Ngouabi University Brazzaville Congo Higher Institute of Architecture Town Planning Building and Public Works Denis Sassou Nguesso University Kintl Congo Faculty of Science and Technology Marien NGOUABI University Congo Geological and Mining Research Center Ministry of Mining and Geology Brazzaville Congo Research Group of Physical Chemical and Mineralogical Properties of Materials Brazzaville Congo National Institute for Research in Engineering Sciences Innovation and Technology Brazzaville Congo

The concrete mixed to sugarcane bagasse fibers and polypropylene fibers prepared with varied conditions were presented. The aim of our study is to formulate a concrete mixed with sugarcane bagasse fibers, which will gradually replace the conventional polypropylene fibers often used. We formulated all our concretes using the dreux gorisse method. We used an oven calibrated at 105˚C to dry the washed fibers. We also carried out tensile splitting and compression tests, at 28 and 112 days of age. The reinforcement mechanisms of sugarcane bagasse fibers and polypropylene fibers concretes were subjected to tensile splitting and compression tests after total immersion of the specimens in tap water at 28 and 112 days. Porosity at 28 days, mass loss and drying shrinkage at 80 days were also studied. The curing processes of concretes containing 0.10, 0.15, 0.17, 0.23 and 0.25% bagasse fibers were compared with those of ordinary concretes containing no fiber. The results showed that the addition of bagasse fibers reduces mechanical strength and porosity. In summary, specimens SBC-0.15 and SBC-0.17 showed the best results for all fibers. We plan to do the same work, but this time with raffia or palm nut fibers.

关键词： Concrete Bagasse Fiber Polypropylene Fiber Tensile Test Compression Test

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Influence of Climate and Tectonics on the Crystallization of Carnallite and Related Salts in the Congolese Atlantic Basin during the Lower Cretaceous, Republic of Congo

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Open Journal of Geology 2023年第1期13卷 51-71页

作者： Daphne Steimer Garcia Nkokani Milandou hilaire elenga Maurice Dieudonné Malounguila Nganga Mathurin Enama Mengong Center for Geological and Mining Research Brazzaville Republic of Congo Faculty of Science and Technology Geology Course Marien Ngouabi University Brazzaville Republic of Congo Newco Mining SA Pointe-Noire Republic of Congo

Lithological, petrographic, and morphoscopic studies were conducted on cuttings and cores from three boreholes drilled in the Loemé salt, Kanga site, Republic of the Congo, to determine 1) the preferential conditions for crystallization of carnallite and associated salts and 2) to reconstruct paleoenvironmental and paleoclimatic conditions at the time of sedimentation. Sequential analysis of logs, sedimentary structures, carnallitite facies and associated salts concluded to the existence of a potassic carnallitite lagoon basin with low water cover, on a very wide and extensive plateau, affected by coastal waves and swells resulting from successive collapses. This basin evolved in two phases: confined and then open. The regular stratifications of halite, the rhythmicity of the halite-carnallitite elementary sequences are characteristic of salts that precipitated in relatively stable brines. These salts are therefore tectonosedimentary. The brecciated facies of the carnallitites sometimes associated with tachyhydrite result from the evolution of these deposits into salt crusts reworked by the surges into subaquatic allochemical gravelly cords under water. These crusts mark stages of partial and complete drying of the basin in a very hot and arid climate. Prolonged exposure of halite brines as well as their homogenization by surges accelerated evaporation and their abrupt evolution into carnallite brines obstructing the fossilization of sylvite. The precipitation of tachyhydrite marks the final stage of the successive complete drying of the basin.

关键词： Potassium Lagoon Surges Stable Brines Rhythmicity Elementary Sequences Salt Crusts Arid Climate Republic of the Congo

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Miocene Foraminifera Biostratigraphy and Interpretation North Deep Sea Block of the Congolese Atlantic Basin

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Open Journal of Geology 2021年第7期

作者： Nehl Dorland Kobawila hilaire elenga Louis Richard Ngatse

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Sedimentology and Mineralogy of Surface Formations of the Mossendjo Area (Republic of Congo): Paleoenvironmental and Paleoclimatic Implications

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Open Journal of Geology 2021年第10期

作者： Jude Nogelvi Ngakosso Ngolo hilaire elenga Mambou Jean Romuald Malounguila Ganga Dieudonné Malanda Edmond

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