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Petrographic and Geochemical Characteristics of the Granitoids in the South of Godé (North of the Square Degree of Léo-Burkina Faso, West Africa)

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International Journal of geosciences 2024年第2期15卷 106-118页

作者： Adama Ouédraogo Yaméogo Hubert Gounwendmanaghré Zongo Pascal Ouiya Omar Akonyiré Abraham Seydoux Traoré Saga Sawadogo Séta Naba Unité de Formation et de Recherche en Sciences et Technologies Département des Sciences de la Vie et de la Terre Université Norbert Zongo Koudougou Burkina Faso Unité de Formation et de Recherche en Sciences de la Vie et de la Terre Laboratoire Géosciences et Environnement (LaGE) Départe-ment des Sciences de la Terre Université Joseph Ki-Zerbo Ouaga Burkina Faso Ecole Supérieure d’Ingénieries Université de Fada N’gourma Fada N’Gourma Burkina Faso Ecole Normale Supérieure (ENS)/Institut des Sciences et de Technologie (IST) Ouaga Burkina Faso

South of Godé, in the central-western region of Burkina Faso, granitoids of Paleoproterozoic age are similar to those of the Man/Leo shield. This study focused on the petrographic and geochemical characteristics of these granitoids, with the following results: 1) The tonalite that outcrops in the south-west of the study area belongs to the TTG group or first generation granitoids. They are most often ribboned at outcrop and have a geochemical signature close to that of Archean TTGs. Tonalite has a metaluminous character and the REE spectrum indicates that it may be derived from partial melting of basic magmatic rocks. 2) Biotite granites have no outcrop structure. They are weakly metaluminous to peraluminous and potassic to highly potassic. Their rare earth spectra indicate that they may be derived from the partial melting of TTG granitoids. 3) Geotectonic diagrams show that the granitoids studied to the south of Godé were emplaced in an active tectonic context similar to that of present-day subduction zones.

关键词： Burkina Faso Godé Man/Leo Shield Petrography Geochemistry Partial Melting Geotectonic Setting

Monitoring Forest Recovery in Protected Forests of Northern Côte d’Ivoire Using Landsat Imagery and Intensity Change Analysis

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Advances in Remote Sensing 2022年第2期11卷 17-37页

作者： N’Guessan Simon Andon Avy Stéphane Koffi Farid Traoré Patrick N’Gatta Department of Geography Université Peleforo GON COULIBALY Korhogo C&ocirc te d’Ivoire Department of geosciences Université Peleforo GON COULIBALY Korhogo C&ocirc te d’Ivoire Institut de l’environnement et de Recherches Agricoles Ouagadougou Burkina Faso

In this paper, the initiatives of reforestation of the national forests of the North of the Côte d’Ivoire were examined using geomatics and the analysis of change of intensity by taking the case of the protected Forest of Badénou (PFB). A spatial analysis based on multi-spectral and multi-temporal Landsat imagery was carried out to assess land cover changes in the (PFB) over the past two decades and determine whether patterns of change in terms of the intensity of gains/losses of each of the land cover classes were active or dormant between the period before (2000-2013) and after (2013-2019) the reforestation initiative. Five main classes were identified: forest (dry deciduous and gallery forests), tree savannah, shrub/grassy savannah (including agricultural lands), bare lands (bare soils and degraded land areas), and water course. All classes were satisfactorily classified, with an excellent producer’s and user’s and overall accuracies and very good Kappa coefficients. The results showed that between 2000 and 2019, the forest cover in the PFB increased from 7778 ha to 5054 ha, a decrease was marked between 2000 and 2013 of approximately 60% compared to its size in 2000, while a slight increase between 2013 and 2019 (4645 ha to 5054 ha) i.e. around 9%) certainly due to the reforestation since 2016. As for the annual intensities of change for each class in both study periods, changes (gain or loss) in forest and tree savanna were relatively dormant after reforestation, while annual bare land gain was relatively active and marked, indicating that degradation of forests remains a threat to the sustainability of the PFB. Forest degradation has occurred mainly in the eastern parts of the PFB, while the central parts have regained more tree cover. These results can help identify conservation and restoration priorities and improve the overall management of the PFB.

关键词： Forest Degradation Reforestation Forest Cover Monitoring Intensity Change Analysis Desertification

Anomalous phenomena in DC–ULF geomagnetic daily variation registered three days before the 12 May 2008 Wenchuan M_S 8.0 earthquake

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Earth and Planetary Physics 2019年第4期3卷 330-341页

作者： Mei Li Li Yao YaLi Wang Michel Parrot Masashi Hayakawa Jun Lu HanDong Tan Tao Xie China Earthquake Networks Center China Earthquake Administration Beijing 100045 China Laboratoire de Physique et Chimie de l’environnement et de l’Espace Université d’Orléans CNRS Orléans France Hayakawa Institute of Seismo Electromagnetics Co. Ltd. University of Electro–Communications (UEC) Chofu Japan UEC Advanced Wireless Communications Research Center Chofu Japan School of Geophysics and Information Technology China University of Geosciences Beijing 100083 China

The hourly data of the vertical Z and the horizontal H components of 37 ground-based DC-ULF geomagnetic stations are examined during 20 April-12 May 2008. On 9 May 2008, three days before the Wenchuan MS 8.0 shock, anomalies-a double low-point and a decreased amplitude-are registered on the curves of the Z component at 25 stations in a large-scale area surrounding the Wenchuan epicentral area. The H component shows none of the double low-point phenomenon but does exhibit a reduced magnitude at the same time. The geomagnetic index Kp is also examined and indicates that the anomalies appear at a solar quiet period. The appearing time shift(Tzs) between the first low-point on May 9 and the minimum point occurring time of May 1-5, 2008 is also *** results show that Tzs is on the order of 1-2 hours earlier or later than usual and there is a 2-6 hours’ gap between these two lowpoints. However, there is still a transition area which includes the epicenter where Tzs=0. Variation amplitude examined on vertical Z increases as the distance from the epicenter decreases. An Earth-air-ionosphere model has been employed to investigate a possible mechanism of this phenomenon and positive results have been unexpectedly attained. All these above-related results tend to prove that the variations of the Z and H on May 9, 2008 during the solar quiet period are probably associated with the forthcoming Wenchuan MS 8.0 earthquake.

关键词： Wenchuan MS 8.0 earthquake geomagnetic abnormity spatial variations Earth-air-ionosphere model

Classification and Spatio-Temporal Change Detection of Land Use/Land Cover Using Remote Sensing and Geographic Information System in the Manouba Region, NE Tunisia

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Journal of Geographic Information System 2023年第6期15卷 652-668页

作者： Nadia Trabelsi Ibtissem Triki Imen Hentati Nizar Rachdi Laboratoire Eau Energie Environnement Ecole Nationale d’Ingénieurs de Sfax Sfax Tunisia Faculte des Sciences de Gafsa Campus Universitaire Gafsa Tunisia Geoengine Geomatics and Geosciences Engineering Rue du lac de Constance Tunis Tunisia

Land use/land cover (LULC) mapping and change detection are fundamental aspects of remote sensing data application. Therefore, selecting an appropriate classifier approach is crucial for accurate classification and change assessment. In the first part of this study, the performance of machine learning classification algorithms was compared using Landsat 9 image (2023) of the Manouba government (Tunisia). Three different classification methods were applied: Maximum Likelihood Classification (MLC), Support Vector Machine (SVM), and Random Trees (RT). The classification aimed to identify five land use classes: urban area, vegetation, bare area, water and forest. A qualitative assessment was conducted using Overall Accuracy (OA) and the Kappa coefficient (K), derived from a confusion matrix. The results of the land cover classification demonstrated a high level of accuracy. The SVM method exhibited the best performance, with an overall accuracy of 93% and a kappa accuracy of 0.9. The ML method is the second-best classifier with an overall accuracy of 92% and a kappa accuracy of 0.88. The Random Trees method yielded the lowest accuracy among the three approaches, with an overall accuracy of 91% and a kappa accuracy of 0.87. The second part of the study focused on analyzing LULC changes in the study area. Based on the classification results, the SVM method was chosen to classify the Landsat 7 image acquired in 2000. LULC changes from 2000 to 2023 were investigated using change detection comparison. The findings indicate that over the last 23 years, vegetation land and urban areas in the study area have experienced significant increases of 31.94% and 5.47%, respectively. This study contributed to a better understanding of the classification process and dynamic LULC changes in the Manouba region. It provided valuable insights for decision-makers in planning land conservation and management.

关键词： Remote Sensing GIS LULC SVM MLC RT Change Detection

Numerical and Geophysical Tools Applied for the Prediction of Mine Induced Seismicity in French Coalmines

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International Journal of geosciences 2012年第4期3卷 834-846页

作者： Marwan Al Heib Institut National de l’environnement Industriel et des Risques

The determination of the influence of mining works and the induced seismicity is essentially obtained, separately from in-situ observations and seismic analysis, field measurements (particularly surface survey) as well as from numerical investigations. The paper presents a methodology applied for the analysis of induced seismicity due to underground coalmines based on combining numerical modelling and seismic analysis. The methodology is based on the comparing between the observations, the seismic activity and the numerical modelling for establishing a close correlation between the location of seismic activity and the induced stresses. The paper presents two case studies using seismic and geotechnical investigations, the first one concerns a fatal accident affected Lorraine coalmine (East France). The second case concerns the application of the methodology on Provence coalmines (South France). The application of the methodology shows such a coupling can be an efficient way for detecting areas subjected to rockburst hazard. This is also a powerful tool for assisting the planning of underground workings in complex geological and mining conditions. The coupling of geotechnical investigations (numerical modelling, in-situ stress measurements) and seismic analysis are strongly recommended.

关键词： Induced Seismicity Numerical Modelling Rockburst Mining Design

Livestock induces strong spatial heterogeneity of soil CO2, N2O and CH4 emissions within a semi-arid sylvo-pastoral landscape in West Africa

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Journal of Arid Land 2017年第2期9卷 210-221页

作者： Mohamed H ASSOUMA Dominique SERCA Frederic GUERIN Vincent BLANFORT Philippe LECOMTE Ibra TOURE Alexandre ICKOWICZ Raphael J MANLAY Martial BERNOU Jonathan VAYSSIERES CIRAD-UMR Selmet Campus International Baillarguet Montpellier 34398 France DP PPZS ISRA-LNERV BP 2057 Dakar Hann Senegal Laboratoire d'Aerologie-OMP Universite Paul Sabatier 14 Avenue Edouard Belin Toulouse 31400 France geosciences environnement Toulouse UMR 5563 & UR 234 IRD Universite Paul Sabatier Avenue Edouard Belin 14 Toulouse 31400 France CILSS 03 BP 7049 Ouagadougou Burkina Faso AgroParisTech-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France IRD-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France

Greenhouse gas （GHG） emissions from the surface soils and surface water receiving animal excreta may be important components of the GHG balance of terrestrial ecosystems, but the associated processes are poorly documented in tropical environments, especially in tropical arid and semi-arid areas. A typical sylvo-pastoral landscape in the semi-arid zone of Senegal, West Africa, was investigated in this study. The study area （706 km2 of managed pastoral land） was a circular zone with a radius of 15 km centered on a borehole used to water livestock. The landscape supports a stocking rate ranging from 0.11 to 0.39 tropical livestock units per hectare depending on the seasonal movements of the livestock. Six landscape units were investigated （land in the vicinity of the borehole, natural ponds, natural rangelands, forest plantations, settlements, and enclosed plots）. Carbon dioxide （CO2）, nitrous oxide （N2O） and methane （CH4） fluxes were measured with static chambers set up at 13 sites covering the six landscape units, and the 13 sites are assumed to be representative of the spatial heterogeneity of the emissions. A total of 216 fluxes were measured during the one-year study period （May 2014 to April 2015）. At the landscape level, soils and surface water emitted an average 19.8 t C-CO2 eq/（hm2.a）（CO2： 82%, N2O： 15%, and CH4： 3%）, but detailed results revealed notable spatial heterogeneity of GHG emissions. CO2 fluxes ranged from 1148.2 （±91.6） mg/（m2.d） in rangelands to 97,980.2 （±4,861.7） mg/（m2.d） in surface water in the vicinity of the borehole. N2O fluxes ranged from 0.6 （±0.1） mg/（m2.d） in forest plantations to 22.6 （±10.8） mg/（m2.d） in the vicinity of the borehole. CH4 fluxes ranged from -3.2 （±0.3） mg/（m2.d） in forest plantations to 8788.5 （±2295.9） mg/（m2.d） from surface water in the vicinity of the borehole. This study identified GHG emission ＂hot spots＂ in the landscape. Emissions from the surface soils were significantly higher in the landscape units most freq

关键词： greenhouse gases soil surface water livestock landscape Senegal

Metallotectic Context of the Mineralization of the Tondabo Gold Prospect(Brobo,Center of Cote d’Ivoire,West Africa)

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International Journal of geosciences 2020年第5期11卷 325-344页

作者： DaI Bi Seydou Mathurin Ouattara Gbele Gnanzou Allou Koffi Gnammytchet Barthelemy Coulibaly Inza Laboratoire des geosciences Cadre de vieEnvironnement et Sciences GeographiquesInstitut National Polytechnique Felix Houphouet-BoignyYamoussoukroCote d’Ivoire Laboratoire de Geologie du Socle et Metallogenie UFR-STRMUniversite Felix Houphouet-BoignyYamoussoukroCote d’Ivoire

The gold mineralization of the Tondabo prospect, located in the northern part of the Oumé-Toumodi-Fettêkro greenstone belt, is mainly hosted in the rhyodacite and to a lesser extent in the mafic volcanics (volcanic lavas and volcanoclastites). These rocks were affected by a hydrothermal alteration marked by quartz veins and veinlets associated with crystals of carbonates, sericite, epidote and sulfides. This hydrothermal alteration induced a pervasive alteration of the surrounding bodies with silicification, chloritization, carbonation and sericitization of the feldspars. The metalliferous paragenesis contains an abundant pyrite, with rare pyrrhotite and chalcopyrite. This mineralization indicates that the Tondabo gold prospect exhibits lithological control. The mineralized deposits are generally affected by a S1 schistosity oriented mainly N000-010° and minority N040-050° with a general dip of 60°-80°to the West;however with rare N-S orientations with a dip of 60°-80° to the East. The drilling intervals show that the highest gold contents are linked to the quartz-carbonates veins and veinlets, which are located in the highly deformed zones, characterizing local shear zones.

关键词： Gold Mineralization Rhyodacite Structures Hydrothermal Alteration Tondabo Cote d’Ivoire

Prospects for Minimizing the Potential Environmental Impacts of the Hydro-Agricultural Dam of M’Bahiakro(Cote d’Ivoire)

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Journal of Water Resource and Protection 2013年第9期5卷 847-853页

作者： Lazare Kouakou Kouassi Innocent Kouassi Kouame Seraphin Kouakou Konan Brou Dibi Soumahoro Moussa Diakaria Kone Dago Gnakri Laboratoire des Sciences de l’eau et de l’environnement Universite Jean Lorougnon GuedeDaloaCote d’Ivoire Laboratoire geosciences et environnement Universite Nangui AbrogouaAbidjanCote d’Ivoire Projet d’Aménagement Hydroagricole de la Vallee du N’Zi ONDR_MINAGRIDimbokroCote d’Ivoire Office National de l’Eau Potable(ONEP) Direction des Ressources en EauAbidjanCote d’Ivoire

This study aims at characterizing the physical environment and suggesting solutions for a better management of the hydro-agricultural dam of M’Bahiakro which is being constructed over the N’Zi River and is the first inflatable dam in Cote d’Ivoire. In this survey, data related to hydrology, characteristics of the dam and the irrigated rice production area were obtained with the Water Resources Agency and the National Office of Rice Development of Cote d’Ivoire. Physicochemical parameters of the N’Zi River were collected seasonally at three monitoring stations. Results showed that the N’Zi River is characterized by a high water level period from April to November and a low water level period from November to April. The gap between the low flows and the high flows is important (about 206 m3/s on average). The annual average flow is 40 m3/s with a standard deviation of 32.52 m3/s and a variation coefficient of 0.88. The SAR average value (1.63) and the average conductivity (78.44 μS/cm) showed that waters of the N’Zi River are of high quality to be used for irrigation. Suspended sediment concentrations do not present significant difference along the river. But the seasonal variations are important;they are higher during the rainy seasons (45.8 mg/L on average) than in the dry seasons (17.7 mg/L on average). The annual solid flux of the N’Zi River is 41897 tons, i.e. 15810 m3 of sediments. The annual sediment flux is important and can lead to high depositions in the line-shaped reservoir of the dam and that calls for attention to control the silting up of the reservoir. Great efforts concerning interdisciplinary approaches, as well as extensive and intensive field work are needed in order to better manage the hydro-agricultural dam of M’Bahiakro.

关键词： Hydrology Irrigation Dam Suspended Sediment N’Zi River

Influence of Land Use Land Cover Change on Groundwater Recharge in the Continental Terminal Area of Abidjan,Ivory Coast

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Journal of Water Resource and Protection 2020年第5期12卷 431-453页

作者： Kouakou Koffi Abdelaziz Yalo Nicaise Luc Séguis Ismaila Ouattara Ouedraogo Moussa Kouassi Kouame Auguste Bamory Kamagate Kone Diakaria Graduate Research Program on Climate Change and Water Resources West African Science Service Center on Climate Change and Adapted Land Use(WASCAL)Department of Applied HydrologyCotonouBenin laboratory of Applied Hydrology National Water InstituteUniversity of Abomey-CalaviCotonouBenin Ird Institute of Research and DevelopmentUniversite de MontpellierMontpellierFrance Laboratoire geosciences et environnement(LGE) UFR Sciences et Gestion de Environnement(SGE)University of Nangui Abrogoua(UNA)AbidjanCote d’Ivoire Direction des ressources en eau(DRE) Office National de l’Eau Potable(ONEP)AbidjanCote d’Ivoire

The process by which rainfall reaches the aquifer in a sedimentary area is infiltration. This process could be affected quantitatively or qualitatively by the changes in the land use land cover (LULC) as a result of anthropogenic activities which could affect groundwater reserves. This study focuses on the influence of LULC change on groundwater recharge in the context of urbanization and population growth. Four weather stations data and satellite image data were used in order to evaluate water infiltration which is the amount of water that reaches the piezometric surface from 1990 to 2016. The spatial-temporal LULC change in relation to urbanization sprawl was assessed based on a series of Landsat images for 1990, 2000 and 2016. The maximum likelihood pixel-based on classification method was used to analyze the spatial-temporal LULC dynamics. The Thiessen polygon method was used for the mean area precipitation computation. The recharge was determined using water balance method after determining the runoff based on the Soil Conservation Service curve number method. The results show an increase in built-up and agricultural land, while the forest and shrub areas declined with water body remaining unchanged over the period 1990-2016. The decline in forest could be imputed to the demographic and socio-economic growth as expressed by the expansion of agriculture and urbanization. Groundwater recharge and runoff results are respectively 34%, 20% in 1999;21%, 46% in 2000 and 26%, 14% in 2016 of rainfall and show their strong dependence on precipitation and LULC change.

关键词： Groundwater Recharge Runoff LULC SCS Curve Number Continental Terminal Abidjan