Petrographic, Geochemical and Zircon Typology of Neoproterozoic Granitoids: Evidence of Continental Thickening in Saghro Arc (Eastern Anti-Atlas, Morocco)     

M. El Baghdadi  Abdelmajid El Bouikhari  A. Jouider  A. Benyoucef  S. Nadem 《Gondwana Research》2001,4(4):612

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Diagenetic and metamorphic history of the Umm Nar BIF,Eastern Desert,Egypt     

M. M. El Aref  A. El Dougdoug  M. Abdel Wahed  A. W. El Manawi 《Mineralium Deposita》1993,28(4):264-278

The Umm Nar BIF was formed in a sedimentary environment. It is confined to an upper stratigraphic zone of pre-Pan-African metamorphosed shelf deposits. During the Pan-African deformational history, the BIF and the host metasediments were tectonically' overlain by ophiolitic melange succession. The metasediments and the mélange were subjected to a major folding phase and then thrust over the “Shaitian” sheared granite, prior to the intrusion of syn- to late- orogenic granitoids. The BIF is divisible into two main types: oxide-bands including magnetite and hematite, and oxide-silicate bands including magnetite, hematite and stilpnomelane. The associated gangues are quartz, calcite, epidote, garnet, plagioclase, graphite and muscovite. Rhythmic banding and lamination, cross-lamination and flaser structure are the most prominent primary features in the IF bands. The iron minerals and the associated gangue show a variety of textural aspects and microscopic interrelationships which indicate successive episodes of mineral accumulation and formation, involving deposition, recrystallization, blastic growths, overgrowths, replacement and deformations, during continuous burial and subsequent tectonic deformations. Editorial handling: DR  相似文献   

Salinization processes in the unconfined aquifer of Bou-Areg (NE Morocco): A geostatistical,geochemical, and tomographic study   总被引：1，自引：0，他引：1  

F. El Yaouti  A. El Mandour  D. Khattach  J. Benavente  O. Kaufmann 《Applied Geochemistry》2009

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Building models for automatic landslide-susceptibility analysis,mapping and validation in ArcGIS   总被引：4，自引：1，他引：3  

J. D. Jiménez-Perálvarez  C. Irigaray  R. El Hamdouni  J. Chacón 《Natural Hazards》2009,50(3):571-590

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Evaluation of alternatives for lowering the groundwater table in a village in upper Egypt affected by the construction of the New Naga Hammadi barrage     

Neveen B. Abd El Mageed  Amgad S. El Ansary  Ashraf M. Ghanem  Gamal H. Elsaeed 《Environmental Geology》2009,57(1):195-202

The Egyptian government is replacing the existing Naga Hammadi barrage, located across the Nile River some 450 km south of Cairo, with the New Naga Hammadi barrage (NNHB) to incorporate a hydropower plant and to improve conditions for river traffic. The new structure will lead to an increase in river water levels, both locally near the new barrage and upstream. The rise in river water levels will in turn result in changes in groundwater levels in the aquifer system up and downstream of the barrages. In this paper, an area is chosen, which is expected to suffer from a high groundwater table after the construction of the NNHB, to investigate the problem and propose alternatives for lowering the groundwater levels. The study area is a village called Bakhaness, with an area of 588 ha. It is located some 1.5 km upstream of the NNHB. A computer model (MicroFEM) has been used to simulate the groundwater conditions before and after construction of the NNHB. Alternatives for lowering the groundwater table are proposed, simulated and evaluated. The systems, which are assessed are a municipal sewer system, a system of perforated pipes in urban areas, and tile drainage with different values of efficiency in agricultural areas.  相似文献   

Tectonic relationships of Southwest Iberia with the allochthons of Northwest Iberia and the Moroccan Variscides     

José Fernando Simancas  Antonio Azor  David Martínez-Poyatos  Abdelfatah Tahiri  Hassan El Hadi  Francisco González-Lodeiro  Andrés Pérez-Estaún  Ramón Carbonell 《Comptes Rendus Geoscience》2009,341(2-3):103-113

The Iberian Massif poses a problem of relationships between its northwestern and southern parts. Suture terranes (ophiolites and high-pressure rocks) crop out in NW Iberia but only as allochthonous units, unconnected from their root zone. Sutures cropping out in SW Iberia are discussed in order to relate them to the unknown root of the NW Iberia allochthons. On the other hand, the Moroccan Variscides are very briefly presented with a view to propose their correlation with the Iberian zones. Particularly important is the transition from the Variscides to the Paleoproterozoic basement in Morocco, which is a key argument for palaeogeographic reconstructions.  相似文献   

Development and evaluation of biodiesel fuel and by-products from jatropha oil     

G. El Diwani  N. K. Attia  S. I. Hawash 《International Journal of Environmental Science and Technology》2009,6(2):219-224

Biodiesel is an environmentally friend renewable diesel fuel alternative. Jatropha seeds can be a feedstock to produce a valuable amount of oil to be converted to biodiesel using transesterification reaction. Jatropha plant has been successfully grown in southern Egypt using primary treated municipal wastewater for its irrigation. Abench scale production of biodiesel from Jatropha oil (using methyl alcohol and sodium hydroxide as catalyst) was developed with methyl esters yield of 98 %. Biodiesel was produced on a pilot scale based on the bench scale experiment results with almost the same methyl esters yield of 98 %. The produced biodiesel was evaluated as a fuel and compared with petroleum diesel according to its physical and chemical parameters such as viscosity, flash point, pour point, cloud point, carbon residue, acid value and calorific value. The experimental techniques and product evaluation results show that such properties of the produced biodiesel are near to that of petroleum diesel. A mass balance representing the transesterification process is presented in this study. Glycerol of 85 % purity was produced and evaluated as a valuable byproduct of the process. Free fatty acids and sodium phosphate salts which have industrial interesting are also produced and evaluated.  相似文献   

Triassic stretching directions in Iberia and North Africa inferred from magnetic fabrics   总被引：1，自引：0，他引：1  

Ruth Soto  Antonio M. Casas‐Sainz  Beln Oliva‐Urcia  Cristina García‐Lasanta  Esther Izquierdo‐Llavall  Bennacer Moussaid  Jos Carlos Kullberg  Teresa Romn‐Berdiel  Yolanda Snchez‐Moya  Alfonso Sopea  Sara Torres‐Lpez  Juan Jos Villalaín  Hamidou El‐Ouardi  Inmaculada Gil‐Pea  Ann M. Hirt 《地学学报》2019,31(5):465-478

During the Triassic, Iberia and western North Africa displayed a unique situation in relation with the Central and North Atlantic opening and westward expansion of the Tethys. Unravelling the stretching direction in Triassic deposits of the studied area can help in our understanding of this scenario. The tectonic setting is characterized by localized basins with strong thickness variations greatly influenced by previous post‐Variscan mechanical discontinuities. In this work, we revise and compile magnetic fabric data from eight Triassic depocentres in terms of defining the stretching direction (i.e. magnetic lineation), resulting from extensional deformation of this period. Data show the importance of the opening of the Atlantic rift as the leading process during the Triassic. Dextral transtension can explain the deflection of the extensional direction observed in most studied depocentres that is caused by the activity of previous major oblique faults.  相似文献   

Numerical analyses of fault–foundation interaction     

I. Anastasopoulos  A. Callerio  M. F. Bransby  M. C. R. Davies  A. El Nahas  E. Faccioli  G. Gazetas  A. Masella  R. Paolucci  A. Pecker  E. Rossignol 《Bulletin of Earthquake Engineering》2008,6(4):645-675

Field evidence from recent earthquakes has shown that structures can be designed to survive major surface dislocations. This paper: (i) Describes three different finite element (FE) methods of analysis, that were developed to simulate dip slip fault rupture propagation through soil and its interaction with foundation–structure systems; (ii) Validates the developed FE methodologies against centrifuge model tests that were conducted at the University of Dundee, Scotland; and (iii) Utilises one of these analysis methods to conduct a short parametric study on the interaction of idealised 2- and 5-story residential structures lying on slab foundations subjected to normal fault rupture. The comparison between numerical and centrifuge model test results shows that reliable predictions can be achieved with reasonably sophisticated constitutive soil models that take account of soil softening after failure. A prerequisite is an adequately refined FE mesh, combined with interface elements with tension cut-off between the soil and the structure. The results of the parametric study reveal that the increase of the surcharge load q of the structure leads to larger fault rupture diversion and “smoothing” of the settlement profile, allowing reduction of its stressing. Soil compliance is shown to be beneficial to the stressing of a structure. For a given soil depth H and imposed dislocation h, the rotation Δθ of the structure is shown to be a function of: (a) its location relative to the fault rupture; (b) the surcharge load q; and (c) soil compliance.  相似文献   

Operational performance of current synthetic aperture radar sensors in mapping soil surface characteristics in agricultural environments: application to hydrological and erosion modelling   总被引：1，自引：0，他引：1  

Nicolas Baghdadi  Olivier Cerdan  Mehrez Zribi  Véronique Auzet  Frédéric Darboux  Mahmoud El Hajj  Rania Bou Kheir 《水文研究》2008,22(1):9-20

Synthetic aperture radar (SAR) sensors are often used to characterize the surface of bare soils in agricultural environments. They enable the soil moisture and roughness to be estimated with constraints linked to the configurations of the sensors (polarization, incidence angle and radar wavelength). These key soil characteristics are necessary for different applications, such as hydrology and risk prediction. This article reviews the potential of currently operational SAR sensors and those planned for the near future to characterize soil surface as a function of users' needs. It details what it is possible to achieve in terms of mapping soil moisture and roughness by specifying optimal radar configurations and the precision associated with the estimation of soil surface characteristics. The summary carried out for the present article shows that mapping soil moisture is optimal with SAR sensors at low incidence angles (<35 ). This configuration, which enables an estimated moisture accuracy greater than 6% is possible several times a month taking into account all the current and future sensors. Concerning soil roughness, it is best mapped using three classes (smooth, moderately rough, and rough). Such mapping requires high‐incidence data, which is possible with certain current sensors (RADARSAT‐1 and ASAR both in band C). When L‐band sensors (ALOS) become available, this mapping accuracy should improve because the sensitivity of the radar signal to Soil Surface Characteristics (SSC) increases with wavelength. Finally, the polarimetric mode of certain imminent sensors (ALOS, RADARSAT‐2, TerraSAR‐X, etc.), and the possibility of acquiring data at very high spatial resolution (metre scale), offer great potential in terms of improving the quality of SSC mapping. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献