检索结果-南通市图书馆

Estimation of Groundwater Recharge Using Water Table Fluctuation Method in Bamako and Surrounding Areas, Mali

在线全文

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2024年第9期12卷 230-245页

作者： Ibrahima Konotio Hamadoun Bokar Adama Touré Département de Géologie et Mines Laboratoire Eau et Environnement Ecole Nationale d’Ingénieurs Abderrahmane Baba TOURE ENI-ABT Bamako Mali

Bamako’s geographic and demographic expansion is sure to increase the need for water, and the slow development of the water supply network seems unable to meet this need. The knowledge of the approximate quantity of water reaching the groundwater is crucial, given the high dependence of this city and its surrounding area on groundwater. The aim of this study is to estimate the average groundwater recharge on a monthly scale, based on measurements taken over a 24-month period by using Water Table Fluctuation (WTF). The monthly recharge values obtained from the 15 piezometers in the study area by using WTF method vary from 1.04 to 38.81 mm with an average value of 9.74 mm. As part of the precipitations, these values represent respectively 1.29%, 48.52% and 12.17% of monthly average precipitation. It appears in this study that despite the piezometers belonging to the same climatic zone, the recharge rate can be different because of many factors such as the thickness of the aquifers, the soil and geology type, the local land cover and land use activities.

关键词： Groundwater Recharge Specific Yield Hydrograph Precipitation

Water Quality on the Basement Areas in Kouba-Adougoul and Its Surroundings, Guera Province, Chad

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2024年第9期12卷 388-406页

作者： Tekoum Leontine Benadjingar Nguelmbaye Jean Claude Doumnang Mbaigane Laboratoire de geologie geomorphologie et de teledetection Département de Géologie Faculté de Sciences Exactes et Appliquées Université de N’Djaména N’Djamena Chad Laboratoire hydro-géosciences et reservoirs Département de Géologie Faculté de Sciences Exactes et Appliquées Université de N’Djaména N’Djamena Chad

Water is an essential element for all forms of life. The quantity and quality of water are a problem in places. In Kouba Adougoul and its surroundings in south guera, water-related health problems are reported. That is why this study focuses on the quality of water in the basement areas, of Kouba Adougoul. Our objective is to contribute to a better understanding of water of human consumption in these areas for this, we carried out a physicochemical and bacteriological control on a number water point. Ten water points were collected during May 2022 for analysis. To achieve this objective, we made the in-situ analysis of physical parameters such as pH, electrical conductivity, and temperature. These measurements were made using the multi-parameter kit. The result shows that, the water temperatures vary from 24.4˚C to 27.4˚C proving that the waters are from deep depths. For the use of these waters, it is necessary to take certain precautions. The pH values varied between 6.15 and 7.78, an average of 6.77 giving some waters an aggressive character. It was low mineralized, with electrical conductivity averages ranging from 182.1 to 2100 μS/cm − 1 an average of 586.36 μS/cm − 1 . For the chemical parameters, it is by hydrometric titration that the content of the ions was determined. The determination of the various coliforms in these waters was carried out by its various methods which led to detecting that the waters of Kouba Adougoul are turbid, and present high proportions of nitrates, iron and ammonium. The presence of pathogenic germs, such as total coliforms and thermo-tolerant coliforms in these waters, has been demonstrated. For their consumption, these waters deserve treatment beforehand. In the study area, the anthropogenic activities are considered the most serious sources of groundwater.

关键词： Environmental Pollution Hydrochemistry Aquifers Crystalline Basement Kouba-Adougoul (Guera-Chad)

Litho-Tectonic Architecture of the Dialafara Area, Kédougou-Kéniéba Inlier, Integration of New Field Data and Geophysics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Geology 2024年第3期14卷 279-297页

作者： Mahamadou Diallo Mamadou Yossi Ibrahim Méyès Coulibaly Youssouf Son Amako Dolo Département de Géologie et Mines Ecole Nationale d’Ingénieurs Abderhamane Baba Touré (ENI-ABT) Bamako Mali Sagax Afrique S.A Geophysical Surveys and Consulting Bamako Mali

The Dialafara area is part of the highly endowed Kédougou-Kéniéba Inlier (KKI), West-Malian gold belt, which corresponds to a Paleoproterozoic window through the West African Craton (WAC). This study presents, first of all, an integration of geophysical data interpretation with litho-structural field reconnaissance and then proposes a new litho-structural map of the Dialafara area. The Dialafara area shows a variety of lithology characterized by volcanic and volcano-sedimentary units, metasediments and plutonic intrusion. These lithologies were affected by a complex superposition of structures of unequal importance defining three deformation phases (DD1 to DD3) under ductile to brittle regimes. These features permit to portray a new litho-structural map, which shows that the Dialafara area presents a more complex lithological and structural context than the one presented in regional map of the KKI. This leads to the evidence that this area could be a potential site for exploration as it is situated between two world-class gold districts.

关键词： Kédougou-Kéniéba Inlier Dialafara Mapping Aeromagnetic Data Structure

Lithostructural Control of the Gold Mineralization of the Douta Permit of African Star Resources (Kédougou-Kéniéba Inlier, Southeastern Senegal)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Geosciences 2024年第4期15卷 303-333页

作者： Masse Ndour Papa Moussa Ndiaye Koffi Félix Ekra Alain Ndong Malick Faye Pierre Ndour African Star Resources Yoff Dakar S&#233n&#233gal Dé partement de G&#233ologie Universit&#233 Cheikh Anta Diop Dakar S&#233n&#233gal

The Douta permit of African Star Resources/Thor Explorations, located in the southeast of Senegal, in the Kédougou-Kéniéba Inlier (western part of the West African Craton), is dominated to the East by metasedimentary formations such as greywackes, shales, graphitic shales, quartzites, cherts, claystones and breccias characteristic of the Dialé-Daléma basin. To the West, the mafic formations of the Mako volcanic belt are the most common. Metasedimentary rocks are associated with metavolcanosedimentary terms found at the contact zones between the two (2) Birimian groups. These different geological formations are cut by mafic dolerite and gabbro sills and/or dykes, as well as quartz and microgranite veins. The Douta gold project is crossed from North to South by the MTZ (Main Transcurrent Zone), generally oriented NE-SW and becoming N-S towards the North. The permit is characterized by several shear corridors. The rocks are affected by brittle, brittle-ductile to ductile deformations. The gold mineralization is hosted by a NE-trending shear corridor called the Makosa corridor (Makosa shear zone), therefore sub-parallel to the MTZ. It has a subvertical dip (75˚ to 85˚ to the NW). It is associated with a hydrothermal phase characterized by quartz-sericite-epidote-fine, disseminated pyrite and arsenopyrite ± albite ± chlorite paragenesis. These minerals testify to the existence of a low degree of metamorphism (greenschist facies, epizonal domain) in the area. However, metamorphism reaches amphibolite facies in some places, particularly in the vicinity of intrusive bodies, with the presence of hornblende (amphiboles) and plagioclase. The gold mineralization is mainly hosted by two (2) metasedimentary lithological units: meta-greywackes and shales.

关键词： Douta Kédougou-Kéniéba Inlier Senegal Metasedimentary MTZ Control Gold Mineralization Makosa Corridor

Petrographic and Geochemical Characters of Granites of the Banfora Belt, Burkina Faso (West Africa)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Geosciences 2024年第9期15卷 682-697页

作者： Abdoulaye Ouedraogo Seta Naba Hermann Ilboudo Laboratoire Géosciences et Environnement (LaGE) Département des Sciences de la Terre Unité de Formation et de Recherche en Sciences de la Vie et de la Terre Université Joseph KI-ZERBO Ouagadougou Burkina Faso Bureau des Mines et de la Géologie du Burkina (BUMIGEB) Ouagadougou Burkina Faso

The Banfora’s birimian greenstones belt is located in the western part of Burkina Faso (west Africa). Recent petrographic and lithogeochemical studies have highlighted plutons intruding the metasedimentary and metavolcanic series. These plutonic rocks are composed of leucogranites belonging to the so-called Ferkessedougou’s or Ferké’s batholith, granites, granodiorites, monzodiorites and quartz monzonites. From the lithogeochemical studies, these plutonic rocks have a calc-alkaline and peraluminous character. The rare earth elements spectra of the Ferké’s leucogranites let distinguished two sub-facies. One of the sub-facies is composed of quartz monzonite to granite, while the other is granitic sensu stricto. However, all these plutonic rocks were emplaced in a geodynamic context of subduction followed by collision.

关键词： Burkina Faso Banfora Greenstones Belt Plutons Geodynamic Context Subduction

Plate tectonics from space

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Episodes 2007年第2期30卷 119-124页

作者： Chamot-Rooke N. Rabaute A. Cnrs UMR8538 Ecole Normale Supérieure Laboratoire de Géologie 24 rue Lhomond 75005 Paris France Geosubsight Ecole Normale Supérieure Laboratoire de Géologie 24 rue Lhomond 75005 Paris France

Plate motion at the surface of the Earth can now be directly measured using space geodetic techniques. Measurements spread around the world are accumulating fast, and it is now possible to derive an accurate plate kinematics exclusively based on these space data. We discuss here a new map established at 1：50,000,000 scale summarizing the spectacular results of two decades of geodetic measurements pertinent to plate tectonics.

关键词：地质构造学空间地理科学地球表面

Radiolarian and Planktic Foraminifera Biostratigraphy of the Early Albian Organic Rich Beds of Fahdene Formation,Northern Tunisia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2014年第1期25卷 45-63页

作者： M Ben Fadhel T Zouaghi A Amri M Ben Youssef Département de Géologie Faculté des Sciences de Gafsa-Campus Universitaire Sidi Ahmed Zarrouk–2112 Département des Géoressources CERTE–Technopole de Borj Cédria

The lower part of Fahdene Formation outcropping in northeastern Tunisia is repre- sented by pelagic sequences and characterized by an important siliciclastic fraction that includes ra- diolarian and organic-rich beds of Allam Member. Litho-biostratigraphic analysis based on planktic foraminifera and radiolaria shows that deposition of organic-rich beds of Allam Member is confined to the Microhedbergella rischi Zone through the lower part of Ticinella primula Zone. Age diagnostic radiolaria recovered from these beds has been identified to constrain a direct age of black shale depo- sition. The assemblages can be correlated with the radiolarian biochronozone U.A.10-11 indicating an Early Albian to early Middle Albian in age. Radiolarian assemblages composed of species characteris- tic of U.A.10 biochronozone （A. montisserei, D. gracilis） are associated with radiolarian taxa belonging to Costata Zone （U.A.9 Pseudoeucyrtis hanni and Thanarla pseudodecora）, which can be correlated with Dercourt Member in the Ionian Zone and Paquier level of the Vocontian Basin （southeast of France）. Biostratigraphic and abundance curves analysis has demonstrated significant diversification of cryptocephalic Nassellaria and Archaeodictyomitrae, probably adapted to eutrophic conditions that characterized the Aptian-Albian transition. Ecological conditions may have governed the stratigraphic range of many cosmopolitan taxa （i.e., Pseudodictyomitrae lodogaensis） compared with stratigraphic distributions schemes reported from other domains. The timing of black shales deposition was dia- chronic due to local geodynamic conditions and upwelling currents distribution. The Allam black shales are correlative with the oceanic anoxic event OAElb which is characterized by the widespread of supraregionnally organic-rich beds in the Mediterranean Tethys basins across the Aptian-Albian transition.

关键词： northeastern Tunisia Albian Allam Member black shale radiolaria planktic foraminifera.

Sedimentary facies and paleoenvironmental interpretation of a Holocene marsh in the Gironde Estuary in France

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2006年第6期25卷 52-62页

作者： WANG Jianhua MASSE Laurent TASTET Jean -Pierre Department of Earth Sciences Sun Yat-sen （Zhongshan） University Guangzhou 510275 China Départment de Géologie et Océanographie Université Bordeaux I 33405 Talence cédèx France

The Monards Marsh is located on the northeastern bank of the Gironde Estuary in France. Lithological, sedimentolngical and mi- cropalacontological investigations were made on four cores to determine the evolution of Holocene sedimentary environments and processes in this area over the last 6 000 a. Three main lithological facies are distinguished from bottom to top：（ 1 ） grey laminated silty-sandy clay ; （2） homogeneous dark grey silty clay ; and （ 3 ） compact silty clay. About 26 benthic foraminifera species are identified and divided into six groups according to their ecological characteristics. In association with lithology, sedimentary structures and grainuiometry, the distribution of foraminifera group is used to define external slikke, internal slikke, external schorre, internal schorre, and continental marsh facies. Combined with 14C（AMS） dating, these data indicate four successive paleoenvironments in the Monards Marsh：（ 1 ） Holocene transgression resuited in the development of a basal schorre facies overlying fluvial deposits that transformed to slikke facies sedimentation; the transgression maximum occurred around 5 600 to 5 4430 a BP and was inferred to be associated with the last phase of the rapid Holocene sea-level rise; （2） post-trangressive maximum sedimentation resuited in a regressive sequence of deposits prograding towards the estuary, corresponding to the stahilisation of sea level after 5 4430 a BP; （3） a slight positive tendency in the sea level around 2 800 a BP recorded in the central part of the marsh; and （4） the wetland to a continental marsh environment. The sequential pattern for the evolution of wetlands in this estuarine area during the Holocene is fluvial facies - blackish schorre facies - slikke facies - blackish schorre facies - continental marsh facies. Characteristics of sedimentary facies distribution and evolution reveal that the development of Holocene salt marsh in this area was controlled by the sea-level change and tidal r

关键词： marsh sedimentation benthic foraminifera,^ 14C dating Holocene sea-level fluctuation paleoenvironment

Chemical and Sr-Nd compositions and ^(40)Ar/^(39)Ar ages of NW-trending dolerite dikes of Burkina Faso: Evidence for a Mesoproterozoic magmatism in the West African Craton

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第6期9卷 1957-1980页

作者： Boukare Tapsoba Ching-Hua Lo Urbain Wenmenga Yoshiyuki Iizuka Sun-Lin Chung Gregory Shellnutt Department of Geosciences National Taiwan University UFR-SVT Département de Géologie Université Pr.Joseph Ki-Zerbo de Ouagadougou Institute of Earth Sciences Academia Sinica Department of Earth Sciences National Taiwan Normal University

The Paleoproterozoic basement of the northeastern part of the Leo-Man craton is intruded by generally NW-trending dikes. These regional scale dikes extend over 1000 km in Burkina Faso, Mali and Niger. We present chemical and Sr-Nd isotope compositions, as well as 40 Ar/39 Ar ages of these dikes with the following strikes N98°-N112°, and N114°-N124° in NE Burkina Faso. Field relationships show that the dikes are posterior to all other rock types dated between 2.26 Ga and 2.0 Ga. Chemical data indicate that the dikes are continental flood basalts and composed of low-Ti(TiO2 ≤ 2 wt.%) sub-alkaline basalts and andesites. They exhibit a minor negative Europium anomaly(0.86-0.99) and slightly fractionated REE patterns((La/Yb)_N= 2.5-9.1; Yb_N = 9.5-19.9). The ratios of Th/Ta(1.3-11.4) and Ce/Pb(5.2-58.5)suggest a varying crustal assimilation of the dike magmas during ascent in the continental crust for all studied samples. Calculated P-T conditions indicate that the magma reached temperatures of 1285 ℃(calculated from olivine compositions) and pressures of 6.9 kbar(calculated for pyroxene minerals).Calculated initial 87 Sr/86 Sr(0.70040-0.70260) and ε_(Nd)(t)=+2.1 to-3.5 at 1575 Ma,also point to a crustal contamination with the most primitive samples showing T_(DM) values of 1946 Ma and 2154 Ma. The low values of La/Ba(<0.2) and Nb/La(<1.0), contrast with the low Th/Nb(<0.9), and suggest a lithospheric mantle or subduction-modified mantle as possible source for the dikes. Sr-Nd data, Mg# and NbTa-Zr-Y-Th-Tb-Yb compositions further suggest that the most primitive samples were emplaced in a none orogenic setting and their magmas were subjected to variable crustal contaminations. Literature and the present whole rock 40 Ar/39 Ar age determinations show that the dikes were emplaced during a widespread Mesoproterozoic magmatism between 1.6 Ga and 1.2 Ga, and were affected by a thermal event causing the argon systematics resetting, best constrained by the date of sample KK1(123

关键词： Mafic dike swarm Depleted mantle Mesoproterozoic Continental tholeiites Nuna West African Craton