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Bouchra Baidada Abdelkhalek Alansari Basem Zoheir Said Ilmen Abderrahmane Soulaimani Moha Ikenne 《Chemie der Erde / Geochemistry》2018,78(4):462-478
The Imiter inlier at the eastern Anti-Atlas chain (Morocco) hosts a world-class epithermal Ag-Hg deposit, and several occurrences of sulfide-magnetite mineralization. These occurrences are confined to transcurrent faults that cut mildly to highly potassic I- and S-type granite intrusions (e.g., Igoudrane, Bou Teglimt, Taouzzakt and Bou Fliou).In this contribution, we present new field, petrographic and microanalytical data of the Bou Fliou sulfide-magnetite mineralization in the northwestern part of the Bou Teglimt granodiorite intrusion (567?±?6Ma). Field and microscopic investigations reveal pervasive silicification and potassic alteration associated with iron oxides-rich (>10?vol %) veins, stockworks, and breccias along NE-SW faults. The ore minerals are mainly magnetite, hematite, chalcopyrite, pyrite, sphalerite, Ag-galena, cobaltite, and less abundant Bi-sulfosalts (i.e., cosalite, galenobistmuthite, and llilanite-gustavite). The low-titanium iron oxides (magnetite and hematite), widespread iron-rich breccia, association with crustal scale fault zone, pervasive alteration, and overprinting mineral assemblages suggest a shallow level IOCG-style mineralization. High-order splays of the major fault zone could have provided effective traps for magmatic and basinal Cu and Zn-Pb hydrothermal fluids. The ～550 Ma intrusive phases in the region could have contributed by fluid, elements or heat in a local effective blumbing. The mineralogical and ore textural criteria reflecting ore formation at a realtively shallow crustal environment, but a fluid inclusion study is needed to characterize the ore fluids and mechanism of ore deposition. 相似文献
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Mahallem Abderrahmane Roudane Mohamed Krimi Abdelkader Gouri Sid Ahmed 《Landslides》2022,19(5):1249-1263
Landslides - This work aims to develop a Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) in-house code for modelling landslide–water interaction problems. While we consider the... 相似文献
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Multivariate statistical methods and inverse geochemical modeling were jointly used to deduce the genetic origin of chemical parameters of surface water in the Oued Chemora Basin. The analysis of variance indicates that variations of all parameters at the three stations are significant except for pH and T (p > 0.05). R-mode cluster analysis reveals two distinct groups at each station and led to the conclusion that the major ion chemistry in the three stations is derived from organic and artificial fertilizers due to agricultural activities in the area and water–rock interaction. Mineral saturation indices, calculated from major ions, indicate that the surface water is generally super-saturated with carbonate phases, and all the water samples are under-saturated with respect to gypsum, halite, and CO2(g). In a broad sense, the reactions responsible for the hydrochemical evolution in the Basin fall into three categories: (1) dissolution of evaporite minerals; (2) precipitation of carbonate minerals; and (3) ion exchange. 相似文献
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Mimoun Boughriba Abderrahmane Melloul Yassine Zarhloule Abdelillah Ouardi 《Comptes Rendus Geoscience》2006,338(11):768-774
The succession of drought years and excessive abstraction in the plain of Triffa caused deterioration in water quality and endangers future exploitation of groundwater resources. A combination of geophysical surveys, including electrical resistivity and hydrochemical data has been used to identify the geographical extension of salinization and identify its origin. Electrical conductivity measurements are used to show the history of salinization in space and time. In this paper, a first conceptual model of the brackish springs has been established. To cite this article: M. Boughriba et al., C. R. Geoscience 338 (2006). 相似文献
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Khadidja Ouzegane Jean-Robert Kienast Abderrahmane Bendaoud Amar Drareni 《Journal of African Earth Sciences》2003,37(3-4):207
The In Ouzzal terrane (Western Hoggar) is an example of Archaean crust remobilized during a very-high-temperature metamorphism related to the Paleoproterozoic orogeny (2 Ga). Pan-African events (≈0.6 Ga) are localized and generally of low intensity. The In Ouzzal terrane is composed of two Archaean units, a lower crustal unit made up essentially of enderbites and charnockites, and a supracrustal unit of quartzites, banded iron formations, marbles, Al–Mg and Al–Fe granulites commonly associated with mafic (metanorites and garnet pyroxenites) and ultramafic (pyroxenites, lherzolites and harzburgites) lenses. Cordierite-bearing monzogranitic gneisses and anorthosites occur also in this unit. The continental crust represented by the granulitic unit of In Ouzzal was formed during various orogenic reworking events spread between 3200 and 2000 Ma. The formation of a continental crust made up of tonalites and trondhjemites took place between 3200 and 2700 Ma. Towards 2650 Ma, extension-related alkali-granites were emplaced. The deposition of the metasedimentary protoliths between 2700 and 2650 Ma, was coeval with rifting. The metasedimentary rocks such as quartzites and Al–Mg pelites anomalously rich in Cr and Ni, are interpreted as a mixture between an immature component resulting from the erosion and hydrothermal alteration of mafic to ultramafic materials, and a granitic mature component. The youngest Archaean igneous event at 2500 Ma includes calc-alkaline granites resulting from partial melting of a predominantly tonalitic continental crust. These granites were subsequently converted into charnockitic orthogneisses. This indicates crustal thickening or heating, and probably late Archaean high-grade metamorphism coeval with the development of domes and basins. The Paleoproterozoic deformation consists essentially of a re-activation of the pre-existing Archaean structures. The structural features observed at the base of the crust argue in favour of deformation under granulite-facies. These features are compatible with homogeneous horizontal shortening of overall NW–SE trend that accentuated the vertical stretching and flattening of old structures in the form of basins and domes. This shortening was accommodated by horizontal displacements along transpressive shear corridors. Reactional textures and the development of parageneses during the Paleoproterozoic suggest a clockwise P–T path characterized by prograde evolution at high pressures (800–1050 °C at 10–11 kbar), leading to the appearance of exceptional parageneses with corundum–quartz, sapphirine–quartz and sapphirine–spinel–quartz. This was followed by an isothermal decompression (9–5 kbar). Despite the high temperatures attained, the dehydrated continental crust did not undergo any significant partial melting. The P–T path followed by the granulites is compatible with a continental collision, followed by delamination of the lithosphere and uprise of the asthenosphere. During exhumation of this chain, the shear zones controlled the emplacement of carbonatites associated with fenites. 相似文献
6.
Abderrahmane Soulaimani Abderrahim Essaifi Nassrddine Youbi Ahmid Hafid 《Comptes Rendus Geoscience》2004,336(16):1433-1441
During the Late Precambrian–Early Cambrian times, the borders of the Kerdous inlier were affected by normal faults where thick conglomerates (Ouarzazate Group: PIII), grading progressively upwards into Cambrian marine sediments, were accumulated along their hanging walls. This tectonic activity persisted during the Early Cambrian and was accompanied by a magmatic activity resulting mainly in the emplacement of continental tholeiitic basalts. These tectono-sedimentary and magmatic events are related to the crustal extensional episode that affected the northwestern Gondwana margin during the opening of the Iapetus Ocean during Late Proterozoic times. To cite this article: A. Soulaimani et al., C. R. Geoscience 336 (2004). 相似文献
7.
Lorenzo Tomassini Olivier Geoffroy Jean-Louis Dufresne Abderrahmane Idelkadi Chiara Cagnazzo Karoline Block Thorsten Mauritsen Marco Giorgetta Johannes Quaas 《Climate Dynamics》2013,41(11-12):3103-3126
An overview of radiative climate feedbacks and ocean heat uptake efficiency diagnosed from idealized transient climate change experiments of 14 CMIP5 models is presented. Feedbacks explain about two times more variance in transient climate response across the models than ocean heat uptake efficiency. Cloud feedbacks can clearly be identified as the main source of inter-model spread. Models with strong longwave feedbacks in the tropics feature substantial increases in cloud ice around the tropopause suggestive of changes in cloud-top heights. The lifting of the tropical tropopause goes together with a general weakening of the tropical circulation. Distinctive inter-model differences in cloud shortwave feedbacks occur in the subtropics including the equatorward flanks of the storm-tracks. Related cloud fraction changes are not confined to low clouds but comprise middle level clouds as well. A reduction in relative humidity through the lower and mid troposphere can be identified as being the main associated large-scale feature. Experiments with prescribed sea surface temperatures are analyzed in order to investigate whether the diagnosed feedbacks from the transient climate simulations contain a tropospheric adjustment component that is not conveyed through the surface temperature response. The strengths of the climate feedbacks computed from atmosphere-only experiments with prescribed increases in sea surface temperatures, but fixed CO2 concentrations, are close to the ones derived from the transient experiment. Only the cloud shortwave feedback exhibits discernible differences which, however, can not unequivocally be attributed to tropospheric adjustment to CO2. Although for some models a tropospheric adjustment component is present in the global mean shortwave cloud feedback, an analysis of spatial patterns does not lend support to the view that cloud feedbacks are dominated by their tropospheric adjustment part. Nevertheless, there is positive correlation between the strength of tropospheric adjustment processes and cloud feedbacks across different climate models. 相似文献
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Our study region is characterized by a varied age detritus Mio-Plio-Quaternary formations. Some training can be an important groundwater sources (alluvial sand, shell, limestone, gravel). Agriculture in the study area is the first socio-economic activity and the largest consumer of water resources. It is therefore necessary to take into account for effective water management. This may causes a risk of pollution of various kinds: agricultural, industrial, and domestic water overlooked the lack of wastewater treatment plants in the region and that all discharges of sewage are dumped into the river are the Rhumel no prior treatment. Wadi Rhumel water pollution factors are multiple and related primarily to the agricultural vocation of the area, the nature of different domestic and industrial discharges. We note that the discharge of wastewater from the town of Tadjenanet and Chelghoum Laid is at wadi Rhumel, the latter during low water turns into open sewer. In times of water shortage, intensive pumping on the outskirts of the wadi locally generates an immigration of a possible pollution load to groundwater. Two major cities in our study area are located along of wadi Rhumel with an estimated population over 100,000 inhabitants. Both towns have uncontrolled landfills where one is located at the upstream of wadi Rhumel. Faced with this alarming environmental situation and the lack of treatment plants, we contribute to the study of the impact of wastewater on the quality of surface and groundwater through a physicochemical analysis interpretation. 相似文献
10.
Mohamed Yacine Tebbouche Djamel Machane Souhila Chabane El-Hadi Oubaiche Aghiles Abdelghani Meziani Dalila Ait Benamar Hakim Moulouel Ghani Cheikh Lounis Rabah Bensalem Abderrahmane Bendaoud 《Arabian Journal of Geosciences》2018,11(7):154
The original version of this paper was published with incomplete affiliation. Given in this article are the complete affiliations. 相似文献