Bagzan mount is located in the Aïr massifs region. This locality, which is constituted only by the granites and volcanic formations, knows the difficulty of water supply that depends on rainfall. This present stu...Bagzan mount is located in the Aïr massifs region. This locality, which is constituted only by the granites and volcanic formations, knows the difficulty of water supply that depends on rainfall. This present study has the objective of fracture mapping that allowed to the fractured aquifer in Bagzan mount. The methodological approach used has a treatment of Digital Elevation Model (DEM imagery), hydrogeological and geological approach in the field. This process allowed us to map the lineaments and elaborate a fracturing map after the validation stage. The fracturing map showed that the fractures network is distributed in the N70°-N80°, N60°-N70°, N50°-N60°, and two secondary directions N90°-N100° and N120°-N140°. These fracturing maps allowed us to have precious information in groundwater research in Bagzan mount, due to their geological and hydrogeological complexity.展开更多
In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve th...In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve the region’s water coverage. The cartographic approach developed made it possible to establish synthetic maps based on multi-criteria analysis. The hydrogeological parameters selected include fracturing data, drainage system, slope and piezometric level as well as shallow and deep lithology. The choice of these criteria is based on their physical meaning but also on the availability of data. The integration of all the criteria in a GIS allowed to generate maps of recharge and potential productivity of fractured aquifers in the area. The validation of these thematic maps with independent data confirms their utility as reference standards for accessibility for future resource exploitation. Like any spatialization tool, potential recharge maps will provide valuable information about areas where infiltration is more important, and help control and manage risk zoning. The upward evacuation effect is even more prominent along the lineaments, faults or fractures: thus, to avoid possible pollution and to locate the future hydraulic structures, the analysis of the potential recharge zones remains necessary. The potential productivity index map, in addition to the very punctual sites identified by the fracturing study, made it possible to define areas of high potential productivity.展开更多
Major and trace elements, mineralogy as well as the total organic content of the Upper Cretaceous-Paleocene Marine Series of the Iullemmeden basin in Niger were determined in order to assess their composition, the che...Major and trace elements, mineralogy as well as the total organic content of the Upper Cretaceous-Paleocene Marine Series of the Iullemmeden basin in Niger were determined in order to assess their composition, the chemistry of the paleoenvironment and the nature of the parent crystalline rocks that they evolved from. The major and trace elements were analyzed using a Bruker Tracer IV energy-dispersive hand held X-ray fluorescence spectrometer, the mineralogical analyses were done using a Bruker AXS D8 Discover, while the total organic carbon was calculated by subtraction of inorganic carbon from the total carbon, determined using a CM5014 coulometer (UIC, Joliet, IL, USA) and a LECO SC-144DR instrument. Geochemical indices calculated from major oxides such as CIA, PIA, ICV and CIW have been computed and the results show that the Marine Series are made essentially of clay minerals of the smectite group (montmorillonite), quartz and other accessory minerals like rutile and calcite. Computed ratios of some trace elements such as V/(V + Ni) and V/(V + Cr) showed that the paleoenvironment was dysoxic-oxic and the low values (<2) of the Total Organic Carbon found in the sediments are justified by those poor preservative conditions. Based on Al2O3/TiO2 ratios, the sediments were derived from intermediate to acidic igneous rocks surrounding the basin.展开更多
文摘Bagzan mount is located in the Aïr massifs region. This locality, which is constituted only by the granites and volcanic formations, knows the difficulty of water supply that depends on rainfall. This present study has the objective of fracture mapping that allowed to the fractured aquifer in Bagzan mount. The methodological approach used has a treatment of Digital Elevation Model (DEM imagery), hydrogeological and geological approach in the field. This process allowed us to map the lineaments and elaborate a fracturing map after the validation stage. The fracturing map showed that the fractures network is distributed in the N70°-N80°, N60°-N70°, N50°-N60°, and two secondary directions N90°-N100° and N120°-N140°. These fracturing maps allowed us to have precious information in groundwater research in Bagzan mount, due to their geological and hydrogeological complexity.
文摘In the basement of southwestern Niger, weathering and fractured zones concentrate most of the groundwater. This study focuses on fractured media and aims to identify areas of productivity in this aquifer to improve the region’s water coverage. The cartographic approach developed made it possible to establish synthetic maps based on multi-criteria analysis. The hydrogeological parameters selected include fracturing data, drainage system, slope and piezometric level as well as shallow and deep lithology. The choice of these criteria is based on their physical meaning but also on the availability of data. The integration of all the criteria in a GIS allowed to generate maps of recharge and potential productivity of fractured aquifers in the area. The validation of these thematic maps with independent data confirms their utility as reference standards for accessibility for future resource exploitation. Like any spatialization tool, potential recharge maps will provide valuable information about areas where infiltration is more important, and help control and manage risk zoning. The upward evacuation effect is even more prominent along the lineaments, faults or fractures: thus, to avoid possible pollution and to locate the future hydraulic structures, the analysis of the potential recharge zones remains necessary. The potential productivity index map, in addition to the very punctual sites identified by the fracturing study, made it possible to define areas of high potential productivity.
文摘Major and trace elements, mineralogy as well as the total organic content of the Upper Cretaceous-Paleocene Marine Series of the Iullemmeden basin in Niger were determined in order to assess their composition, the chemistry of the paleoenvironment and the nature of the parent crystalline rocks that they evolved from. The major and trace elements were analyzed using a Bruker Tracer IV energy-dispersive hand held X-ray fluorescence spectrometer, the mineralogical analyses were done using a Bruker AXS D8 Discover, while the total organic carbon was calculated by subtraction of inorganic carbon from the total carbon, determined using a CM5014 coulometer (UIC, Joliet, IL, USA) and a LECO SC-144DR instrument. Geochemical indices calculated from major oxides such as CIA, PIA, ICV and CIW have been computed and the results show that the Marine Series are made essentially of clay minerals of the smectite group (montmorillonite), quartz and other accessory minerals like rutile and calcite. Computed ratios of some trace elements such as V/(V + Ni) and V/(V + Cr) showed that the paleoenvironment was dysoxic-oxic and the low values (<2) of the Total Organic Carbon found in the sediments are justified by those poor preservative conditions. Based on Al2O3/TiO2 ratios, the sediments were derived from intermediate to acidic igneous rocks surrounding the basin.
