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Characteristics of Gold Mineralization at the Baguiomo Gold Panning Site, Koudougou Region, Burkina Faso, West Africa

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Open Journal of Geology 2024年第1期14卷 1-18页

作者： Pascal Ouiya Aziz Fayçal Tarnagda martial eric fozing Ecole Normale Supérieure (ENS) Institut Sciences et Technologie (IST) Ouagadougou Burkina Faso Laboratoire Géosciences et Environnement (LaGE) Earth Sciences Department Ouagadougou Burkina Faso Department of Geology University of Dschang Dschang Cameroon

The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1B deformation. The second phase of D2B deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization.

关键词： Kwademen-Baguiomo Shear Zone Gold Panning Site Gold Mineralization Eburnian Orogeny

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Kinematic Evolution of the Nyakong-Manyi Shear Zone(Adamawa,Cameroon): Constraints from Field Observations and Microstructures,and Implication for Metamorphic P-T-t Estimation

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地球科学学刊:英文版 2023年第5期34卷 1465-1487页

作者： Belmien Robinson Sobze Yemdji Jules Tcheumenak Kouémo eric martial fozing Ludovic Achu Megnemo Julios Efon Awoum Agnes Blandine Kamgang Tchuifong Brice Rostant Tepi Yemele Maurice Kwékam Department of Earth Science University of DschangDschang 67Cameroon Department of Earth Science Faculty of ScienceUniversity of DoualaDouala 24157Cameroon

The Nyakong-Manyi Shear Zone(NMSZ) is a NE-SW elongated corridor found to the northwest of the Foumban-Bankim Shear Zone(FBSZ) along the Central Cameroon Shear Zone. Controversial chronology models has been proposed for the kinematic evolution of the sinistral and dextral shear phases in the Tikar Plain, thus in the FBSZ;early dextral and late sinistral shear phases for some authors and early sinistral and late dextral shear for others. Moreover, the NMSZ kinematic evolution implication on the mylonitization P-T-t path in the area seem to be problematic and the present paper aim is to clear enough those problems;since this shear zone is the main mylonitic corridor that registered the left and right lateral movement in this area. The NMSZ comprises amphibolites, protomylonites, strict sensus mylonites(garnet-kyanite-sillimanite mylonite and garnet-pyroxene mylonite), ultramylonites kyanite-sillimanite and garnet-kyanite-sillimanite gneiss. Field structures testify that the investigated area recorded three deformation phases:(i) the D1deformation phase which is marked by NW-SE to N-S trending S1metamorphic foliation with low to moderate dips(15°–45°) that was transposed during the D2phase, is responsible for a regional metamorphism whose mineral paragenesis is garnet-kyanite-sillimanite;(ii) the early sinistral NNE-SSW to NE-SW shear phase D2marked by S2metamorphic and mylonitic foliations;responsible for, L2stretching mineral lineation, F2fold axes and B2boudins structures;(iii) the late dextral NE-SW shear phase D3, characterized by F3folds, B3boudins and ductile dextral C3shear planes. Mineral paragenesis garnet + kyanite + sillimanite and microstructures within gneiss testify that this rock underwent high grade regional metamorphism whose peak conditions are estimated at 11.5–13.5 kbar/850–900 ℃. After the peak of metamorphism gneiss was overprinted by high grade pressure mylonitization during the early sinistral and late dextral shear deformations. Microstructura

关键词： structural and microstructural features pressure-temperature estimation Nyakong-Manyi Shear Zone Foumban-Bankim Shear Zone Central Cameroon ShearZone tectonics petrology

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Magnetic Characterization of Amphibolites from the Fomopéa Pluton(West Cameroon):Their Implication in the Pan-African Deformation of the Central African Fold Belt

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Acta Geologica Sinica(English Edition) 2012年第1期86卷 73-84页

作者： NJANKO Théophile fozing eric martial KWéKAM Maurice YAKEU SANDJO Angéline Flore NJONFANG Emmanuel Laboratory of Environmental Geology Department of Earth SciencesDschang University Laboratory of Geology ENS Yaounde I University

The Fomopea granitic pluton is emplaced in gnessic and amphibolitic basement. These gneissic and amphibolitic basement rocks are represented in the pluton＇s body as sub-rounded, elongated or stretched xenoliths. Amphibolitic xenoliths display testimonies of two main tectonic events namely：（i） El flattening deformation event characterized by a NW-SE to E-W foliation with a best pole at 246/57 and a mineral stretched lineation with a best line at 293/47; and （ii） E2 compressive event typified by （1） N-S to NNE-SSW steeply dipping foliation; （2） S-type flexion-fold indicating a sinistral shear movement. These amphibolite rocks indicate a magnetic susceptibility magnitude （Km） range from 418 ~SI to 90092 IISI for 87% of the stations showing a ferromagnetic behavior. K-T curves reveal the presence of Ti-poor magnetite as susceptibility mineral carrier. Magnetic foliation and lineation suggest that the N-S strike direction observed in the Bamendou amphibolite is, as pointed out elsewhere in the Central African Fold Belt, of paramount importance in the tectonic evaluation of the Fomopea area, since it has most likely acted as major deformation phase in the second tectonic event in the belt.

关键词： amphibolite anisotropy of magnetic susceptibility (AMS) Pan-African fold belt Cameroon

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Management of Congenital Malformations of the Face in the GbèkèRegion (Côte d’Ivoire)

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Open Journal of Stomatology 2022年第5期12卷 166-174页

作者： eric Kouassi Zegbeh-N’Guessan Rokiatou Kone Pornan Issa Jules Berete Ernest martial Djemi Affoué Ba Diane Marina Amenou Tuo Karna Drissa Grébéret Emmanuel Crezoit Department of Odontology and Maxillofacial Surgery Bouaké University Hospital Bouaké C&ocirc te d’Ivoire Department of Stomatology and Maxillofacial Surgery Bamako University Hospital National Center of Odonto-Stomatology Bamako Mali

Background: Congenital malformations of the face are relatively frequent in the Gbèke region (Côte d’Ivoire). Objectives: Identify the epidemiological aspects, describe the management method, distinguish the anatomical-clinical aspects and identify the therapeutic methods and their results. Material and methods: A retrospective and descriptive study was carried out over a period of 8 years (2012-2019) in the Odontostomatology and Maxillofacial Surgery Department of the University Hospital Centre (Bouaké) and in the “Jean Baptiste Vatelot” religious hospital of Bouaké. The study concerned patients whose congenital malformations of the face had undergone primary surgery. Results: 439 patients were collected, i.e. an annual frequency of 54.88 cases per year. The sex ratio was 1.07 and the mean age was 6.82 years (range 5 months to 48 years). There were 434 (98.86%) cleft lips and palates and 5 (1.14%) Tessier’s clefts. Among the cleft lip and palate, there were 214 (49.31%) cleft lip, 127 (29.26%) cleft palate and 93 (21.43%) combined cleft lip and cleft palate. Surgical treatments numbered 532 and included 293 (55.08%) cheiloplasties, 113 (21.24%) pushback uranostaphyloraphies and 90 (16.92%) double flap palatoplasties. Complications were noted in 43 cases. Conclusion: Congenital malformations of the face were managed relatively late in the Gbèkè region with satisfactory results. Ante-natal diagnosis, early psychotherapy and a better screening system should allow an improvement of the management.

关键词： Congenital Malformation Face

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Biometric Analysis on Genetic Divergence between Parental and Regenerated Accessions in Tall Coconut Palms (Cocos nucifera L.) from International Genebank for Africa and the Indian Ocean

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Open Journal of Genetics 2022年第2期12卷 11-23页

作者： Saraka Didier martial Yao Wentoin Alimata Marie Pierre Daramcoum eric-Blanchard Zadjéhi Koffi Konan Jean Louis Konan Nafan Diarrassouba Bourdeix Roland Raoul Sylvère Sie Irié Arsène Zoro Bi Department of Biochemistry and Genetics Pedagogical and Research Unit (UPR) of Genetics Shea Breeding Program University of Peleforo Gon Coulibaly (UPGC) Korhogo C&#244 te d’Ivoire Centre National de Recherche Agronomique (CNRA) Marc Delorme Research Station of Port-Bou&#235 t Abidjan C&#244 te d’Ivoire CEFE-CNRS Montpellier France Department of Natural Science Nangui Abrogoua University Abidjan C&#244 te d’Ivoire

This study endeavour assesses agromorphological likeness between initial introductions and regenerated accessions at the International Coconut Genebank for Africa and the Indian Ocean (ICG-AIO) based in C?te d’Ivoire. Ten couples of parental (G0) and regenerated (G1) accessions of Tall coconut palms were analyzed using Principal Component Analysis (PCA) and Multiple Analysis of Variance (MANOVA) from 26 agromorphological characters. The main results showed a relative decrease in the expression of the phenotypical traits concerning the component of the fruit, height and vigor of the stem and yield of bunches and fruits after one regeneration cycle. But, a high proportion (69%) of studied characters from leaf, inflorescence and nut components showed likeness between G0 and G1 accessions. After one regeneration cycle, the controlled pollination method guarantees significant conservation of the expression of the majority of agromorphological traits. Consequently, regenerated accessions of Tall coconut palms can be used to pursue research and development programs in C?te d’Ivoire.

关键词： Agromorphological Likeness Controlled Pollination Côte d’Ivoire Regenerated Accessions Tall Coconut

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Comparison between Predicted and Measured X-Ray Output in Some Conventional Radiography Units

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2019年第4期8卷 204-210页

作者： Calvin Didier Njiki Yolande Huguette Ebele Yigbedeck Joseph eric martial Ndjaka Manyol Thierry Ndzana Ndah National Radiation Protection Agency Yaoundé Cameroon

This study aims to investigate how accurate are TASMICS and TASMIP models in predicting the X-ray output of some Conventional Radiology X-ray units with high frequency generators. The X-ray output in microgray per milliampere seconds (μGy/mAs) at 100 cm from the X-ray tube was determined for selected high voltages and taking into account the total filtration. The X-ray output was then measured directly with the multi-purpose detectors (MPD), Raysafe X2. The maximum relative error between measured and predicted values was found to be equal to 20%. The maximum relative error between measured and predicted values obtained demonstrates the difficulty of accurately predicting the X-ray tube output using TASMICS and TASMIP models since they are based on fixed anode angles and different composition of the tungsten anode.

关键词： X-Ray Spectra TASMICS TASMIP

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Assessment of Image Quality Parameters for Computed Tomography in the City of Yaoundé

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Open Journal of Radiology 2018年第1期8卷 37-44页

作者： Calvin Didier Njiki Joseph eric martial Ndjaka Manyol Yolande Ebele Yigbedeck Daniel William Abou’ou Blaise Clovis Yimele Jean Faustin Sabouang National Radiation Protection Agency Yaoundé Cameroon

Performance evaluation of computed tomography is not significant in the Republic of Cameroon in general and more particularly in the city of Yaoundé. Therefore, this work aimed to analyze image performances of 05 CT scanners in 05 medical facilities in the city of Yaoundé, by using the Catphan 700 phantom and test procedures of the Atomic Energy Agency. Five quality control tests were performed on each CT-Scanner. All the CT scanners evaluated showed good results and were not disapproved in three of the five tests performed. The difference between the measured spatial resolution for each of the five CT scanners and the spatial resolution specified by the manufacturer was very high. The low contrast resolution of four of the five CT scanners was found low when compared to the low contrast resolution specified by the manufacturers.

关键词： CT Image Quality Catphan 700

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On the optimal dynamic hedging with nonferrous metals

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Journal of Economic Science Research 2019年第2期2卷 1-21页

作者： eric martial Etoundi Atenga Dept.of Economics and Management University of Yaoundé2 at SoaCameroon

This paper employs multivariate GARCH to model conditional correlations and to examine volatility spillovers and hedging possibilities with nonferrous metals traded on the London Metal Exchange(LME)*** different multivariate GARCH models(diagonal,CCC and DCC)are employed and *** nonferrous metals studied are copper,aluminum,tin,lead,zinc and nickel and span the period from January 6,2000 to February 29,*** multivariate DCC GARCH framework is found to fit the data in an appropriate design and provides results showing the strongest evidence of long-term persistence volatility spillovers between lead and *** also find that the Hurst exponents given by the R/S method are on average 0.94,indicating the existence of a strong degree of long-range dependence in conditional *** average,the cheapest hedge is a long position in lead and a short position in *** most expensive hedge is long nickel and short copper.

关键词： Conditional correlation Spillovers Portfolio weight

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