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Naïma AbouAli Mohamad Hafid El Hassane Chellaï Mohamed Nahim Mahmoud Zizi 《Comptes Rendus Geoscience》2005,337(14):1267-1276
Seismic reflection profiles from the Ifni/Tan-Tan Atlantic margin of southern Morocco, interpreted in the light of well data and field geology from the Western Anti-Atlas, allowed us to establish the seismostratigraphic framework of the syn-rift series and to reveal (i) a compressional structural style in the pre-Triassic basement similar to that established in the adjacent outcropping onshore basement but with an opposed western vergence, (ii) the importance of inherited anterior structures in the formation of Triassic-Liassic rift structures and (iii) an east–west propagation of these rift structures. To cite this article: N. AbouAli et al., C. R. Geoscience 337 (2005). 相似文献
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Impacts of a large Sahelian city on groundwater hydrodynamics and quality: example of Niamey (Niger)
Aïssata B. Hassane Christian Leduc Guillaume Favreau Barbara A. Bekins Thomas Margueron 《Hydrogeology Journal》2016,24(2):407-423
The management of groundwater resources is very important in the semiarid Sahel region, which is experiencing rapid urban development. Impacts of urbanization on groundwater resources were investigated in the unconfined aquifer of the Continental Terminal beneath the city of Niamey, Niger, using water level and chemical data. Hydrodynamic and chemical changes are best described by a combination of factors including the historical development of the city, current land use, water-table depth and topography. Seasonal groundwater recharge occurs with high spatial variability, as indicated by water-level monitoring in all wells, but there was no interannual trend over the 5-year study period. Groundwater salinity shows high spatial variability and a minor rising trend. The highest salinity is in the old city centre, with Na–NO3 dominant, and it increases seasonally with recharge. Salinity is much lower and more variable in the suburbs (Ca–HCO3, Ca–NO3, and Na–NO3 dominant). Nitrate is the main ionic contaminant and is seasonally or permanently above the international guidelines for drinking water quality in 36 % of sampled wells, with a peak value of 112 mg L?1 NO3–N (8 meq L?1). Comparison of urban and rural sites indicates a long-term increase in groundwater recharge and nitrate enrichment in the urban area with serious implications for groundwater management in the region. 相似文献
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Hassane Moutahir Pau Bellot Robert Monjo Juan Bellot Miguel Garcia Issam Touhami 《水文研究》2017,31(1):161-176
Groundwater resources are typically the main fresh water source in arid and semi‐arid regions. Natural recharge of aquifers is mainly based on precipitation; however, only heavy precipitation events (HPEs) are expected to produce appreciable aquifer recharge in these environments. In this work, we used daily precipitation and monthly water level time series from different locations over a Mediterranean region of Southeastern Spain to identify the critical threshold value to define HPEs that lead to appreciable aquifer recharge in this region. Wavelet and trend analyses were used to study the changes in the temporal distribution of the chosen HPEs (≥20 mm day?1) over the observed period 1953–2012 and its projected evolution by using 18 downscaled climate projections over the projected period 2040–2099. The used precipitation time series were grouped in 10 clusters according to similarities between them assessed by using Pearson correlations. Results showed that the critical HPE threshold for the study area is 20 mm day?1. Wavelet analysis showed that observed significant seasonal and annual peaks in global wavelet spectrum in the first sub‐period (1953–1982) are no longer significant in the second sub‐period (1983–2012) in the major part of the ten clusters. This change is because of the reduction of the mean HPEs number, which showed a negative trend over the observed period in nine clusters and was significant in five of them. However, the mean size of HPEs showed a positive trend in six clusters. A similar tendency of change is expected over the projected period. The expected reduction of the mean HPEs number is two times higher under the high climate scenario (RCP8.5) than under the moderate scenario (RCP4.5). The mean size of these events is expected to increase under the two scenarios. The groundwater availability will be affected by the reduction of HPE number which will increase the length of no aquifer recharge periods (NARP) accentuating the groundwater drought in the region. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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The survey of sedimentological and lithostratigraphic Liassic facies of the Todrha–Dades area (southwestern part of the central High Atlas) permits to establish new data on the Tagoudite formation. Its environment deposit and its micropalaeontological content are evidenced in relation with the geodynamic evolution of the High Atlas Basin during the Early Toarcian. To cite this article: M. Ettaki, E.H. Chellaï, C. R. Geoscience 337 (2005). 相似文献
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Discrimination between primary magmatic biotites, reequilibrated biotites and neoformed biotites 总被引:11,自引:0,他引:11
Hassane Nachit Abderrahmane Ibhi El Hassan Abia Mohcine Ben Ohoud 《Comptes Rendus Geoscience》2005,337(16):367
The ternary diagram TiO2–FeO*–MgO (FeO* = FeO + MnO) is proposed as a quantitative objective tool for distinguishing between primary magmatic biotites and those that are more or less reequilibrated, or possibly neoformed, by or within a hydrothermal fluid. The limit of the domains of the primary magmatic biotites, the reequilibrated biotites and the neoformed biotites were determined on the basis of optical, paragenetic and chemical criteria. To cite this article: H. Nachit et al., C. R. Geoscience 337 (2005). 相似文献
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Xiaofen Yang Hongmei Wang Linfeng Gong Hima Hassane Zhengbo Jiang 《Frontiers of Earth Science》2009,3(2):221-225
Fe2+ oxidation by Acidithiobacillus ferrooxidans in pure and mixed cultures was investigated in batch cultures in the presence of arsenate. The pH value was periodically
monitored and Fe2+ content was analyzed by the 1,10-phenanthroline method. ICP-AES was employed for the analysis of As(V) concentration in the
solution phase. Precipitates were collected and analyzed by X-ray diffraction. Slight enhancement of iron bio-oxidation was
observed in mixed cultures with the two greatest As(V) concentrations (1.0 and 5.0 mg/L As), which were enriched from sediment
samples in an abandoned copper mine site. As(V) concentrations decreased with time, indicating either the co-precipitation
with or the adsorption by jarosite, the major sink of solid phase. Our data suggest that biogenically synthesized jarosite
may play an important role in the attenuation of soluble arsenate in natural aquatic environments. 相似文献
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A regional groundwater management system has been elaborated, integrating Relational Database Management System (RDBMS) and various web services. It consists of web geospatial application so-called HydrIS (Hydrogeological Information System) based on Open Source components and technologies, leading to a feasible and low-cost solution. Therefore, HydrIS permits delivery of data from a number of heterogeneous sources to standards supported by the Open Geospatial Consortium (OGC). The protocols used for exchanging data are also derived from OGC standards, i.e., WMS (Web Mapping Service), WFS (Web Feature Service), and WCS (Web Coverage Service). Finally, a geoportal was developed, which consists of client-applications that communicate with different Web Services (WMS, WCS, and WFS) through http-requests. 相似文献
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Hassane El Mkami Henrik Friis Adrian A. Finch G. M. Smith 《Physics and Chemistry of Minerals》2010,37(8):519-528
The location and coordination of Mn2+ paramagnetic luminescent centres in three natural samples of leucophanite (ideally, NaCaBeSi2O6F) have been investigated by electron paramagnetic resonance (EPR) and electron spin-echo envelope modulation (ESEEM) spectroscopy.
Continuous wave (cw)-EPR was carried out at multiple frequencies (9, 94 and 188 GHz) which allowed the precise determination
of the spin Hamiltonian parameters. The simulation of the cw-EPR spectra shows that the signal originates from one manganese
located in a single distorted site. This distortion was close to axial symmetry with a slight rhombicity and was consistent
with an eight coordinated Mn2+ substituting for Ca2+. Spectral differences between the samples could be attributed mainly to D-strain effect. Three-pulse ESEEM spectroscopy was
also used to investigate the coordination environment of the manganese and showed weak coupling between the manganese and
beryllium (9Be), sodium (23Na) and fluorine (19F) nuclei in the second and subsequent coordination spheres. The Mn ligand distances estimated from the ESEEM data are in
good agreement with bond distances estimated from X-ray diffraction data. To our best knowledge, only few ESEEM studies have
been reported so far in Earth science and this is believed to be the first detailed ESEEM study of Mn2+ in a natural mineral system. 相似文献