Geochemistry of the Miocene Zoumi flysch thrust-top basin (External Rif,Morocco): new constraints on source area weathering,recycling processes,and paleoclimate conditions     

Mohamed El Mourabet  Ahmed Barakat  Mohamed Najib Zaghloul  Mohamed El Baghdadi 《Arabian Journal of Geosciences》2018,11(6):126

This study focuses on the Lower-Middle Miocene syn-orogenic flysch deposits of the Zoumi basin to infer source area paleoclimatic conditions, the intensity of source rocks paleoweathering, and mechanical sorting and recycling effects. The mudrocks are enriched in Al₂O₃, Fe₂O₃, CaO, and TiO₂ relative to PAAS and depleted in the other mobile major elements. There are high positive correlations between SiO₂, Al₂O₃, and TiO₂ and negative correlations between SiO₂ and CaO. Geochemically, the mudstones are mainly classified as shales, Fe-shales, and wackes. Various discriminant diagrams were used to reveal the inferred tectonics, source paleoweathering intensity, and paleoclimatic conditions. Chemical index of alteration (CIA) and chemical index of weathering (CIW) values for Lower-Middle Miocene vary from 50 to 80% indicating low to moderate degree of source area weathering compatible with non-steady-state weathering under wet and humid paleoclimatic conditions. Locally (Zoumi mid-section) CIA values are higher (>?80) reflecting intense source area weathering, which may be attributed to high tectonic impulses and more humid conditions during deposition. The combination of ICV-CIA, Al₂O₃-Zr-TiO₂, and Th/Sc-Zr/Sc values suggests the bulk rock is chemically immature and has experienced modest physical sorting and recycling reflecting little transportation until the final deposition.  相似文献   

Assessing crop water requirements on the bases of land suitability of the soils South El Farafra Oasis, Western Desert, Egypt     

W. A. Abdel Kawy  Islam H. Abou El-Magd 《Arabian Journal of Geosciences》2013,6(7):2313-2328

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Correlations of three-component ground motions from the 23 June 2010 Val-des-Bois, Québec, earthquake     

Najib Bouaanani  Cyril Frasson-Botton 《Journal of Seismology》2013,17(3):861-881

In this paper, we investigate the characteristics of three-component ground motions recorded during the $M_\text{w}\,5.2$ Val-des-Bois (Québec) earthquake, which occurred on the 23 June 2010. The earthquake is the largest recorded event in eastern Canada within the last decade. The records analyzed were provided by a strong motion monitoring network, comprising accelerometers located at sites with different soil conditions. The two orthogonal horizontal components and one vertical component at each recording station are uncorrelated to determine their principal directions, and the results obtained are used to characterize intensity ratios between the three uncorrelated components. A new hodograph representation is proposed to highlight the correlation between accelerations and displacement trajectories along various time increments at each recording station. The principal components are discussed in light of seismographic data, local site conditions, and trajectories. Time–frequency analyses of the uncorrelated records are also conducted to compare the distribution of spectral amplitudes and frequency content along the three principal components during the shaking. The results of this work shed more light on the characteristics of three-component ground motions from an important Eastern North America earthquake, and could be used to calibrate simulated multicomponent ground motions in this region.  相似文献   

Geoelectrical and hydrochemical investigations for characterizing the salt water intrusion in the Khanasser valley, northern Syria   总被引：1，自引：1，他引：0  

Jamal Asfahani  Boulos Abou Zakhem 《Acta Geophysica》2013,61(2):422-444

An integrated approach of geoelectrical and hydrochemical investigation surveys was proposed for indicating contact regions between saline and fresh groundwater in the Khanasser valley region, northern Syria. The qualitative and quantitative interpretations of 34 vertical electrical soundings (VES) enable to characterize the salt water intrusion laterally and vertically. The established iso-apparent resistivity maps for different AB/2 spacings obviously indicate the presence of a lowresistivity (less than 4 Ohm·m) zone related to the salt water intrusion in the Quaternary and Paleogene deposits. The different hydrochemical and geophysical parameters, such as electrical resistivity, total dissolved solids (TDS) and major ions concentrations used to characterize the salt water intrusion gave almost similar results in locating and mapping the different boundaries of the groundwater salinity. The proposed approach is useful for mapping the interface between different groundwater qualities, and can be therefore used to successfully characterize the salt water intrusion phenomenon in other semi-arid regions. The application of such an approach is a powerful tool and can be used for water resource management in the water scarce areas.  相似文献   

Estimating phosphorus leachability in reconstructed soil columns using HYDRUS-1D model   总被引：1，自引：1，他引：0  

Abdirashid Elmi  Joumana S. Abou Nohra  Chandra A. Madramootoo  William Hendershot 《Environmental Earth Sciences》2012,65(6):1751-1758

Modern agricultural production uses phosphorus (P) extensively to meet the challenges of feeding rapidly growing population and changing lifestyles, making P a leading source of impairment for rivers and streams in Canada. Developing effective management strategies to reduce P losses from agro-ecosystems requires improved understanding of P transport pathways in the soil. The purpose of this study was to investigate vertical distribution and transport processes of phosphate (PO₄) in reconstructed soil columns using HYDRUS-1D model. Results obtained from field experiments were used to calibrate and validate the HYDRUS-1D model. The results showed that 98% of the total P applied was concentrated in the top 0.2 m of the columns, and decreased progressively with soil depth. The model over-predicted PO₄ adsorption, leading to a weak correspondence between the simulated and the measured results for PO₄. This is a suggestion that the HYDRUS-1D model could not account accurately for the different soil structures found in the undisturbed soil columns and the preferential flow that occurs in these columns. This may be due to the fact that Freundlich isotherm, which is part of the transport equations, could not adequately describe PO₄ adsorption onto the soil particles.  相似文献   

Modeling of dam break wave propagation in a partially ice-covered channel     

Musandji Fuamba  Najib Bouaanani  Claude Marche 《Advances in water resources》2007,30(12):2499-2510

During the last four decades, several numerical formulations and specialized software have been developed in response to studies about dam break (DB) wave propagation and its hydraulic and environmental impacts on downstream hydraulic structures and valleys. These methods cannot, however, be used to predict wave propagation within partially covered channels or reservoirs located upstream of hydraulic structures. In fact, such problems require the modelling of the complex transition from a free surface flow into a pressurized one. Because rivers or channels partially covered with ice sheets are typical examples commonly met in winter in northern climates, it is vitally important to assess ice-cover effects on the DB wave propagation and develop appropriate tools to predict resulting hydrodynamic loads on hydraulic structures downstream. This paper proposes an original numerical formulation to model wave propagation and hydrodynamic pressure in partially covered channels. The proposed formulation uses one-dimensional St. Venant equations to simulate open-water flow and water hammer equations to simulate pressure flow within the partially covered channel. To illustrate the use of the hydrodynamic pressures obtained, a case study is presented where a channel cover and a dam located downstream are modelled using finite elements to investigate their dynamic structural response.  相似文献   

Subsidence et effondrements le long du littoral jordanien de la mer Morte : apports de la gravimétrie et de l'interférométrie radar différentielle     

Damien Closson  Najib Abou Karaki  Musa Jad Hussein  Hassan Al-Fugha  André Ozer  Abdullah Mubarak 《Comptes Rendus Geoscience》2003,335(12):869-879

The Dead Sea shore is affected by major subsidence and sinkholes hazards due to the decrease of the sea level. The frequency of resulting accidents increased during the last four decades. Those phenomena could be at the origin of the catastrophic destruction of a major salt evaporation pond on 22 March 2000. In this paper, we show the main results of eight years of research in gravimetry and radar interferometry devoted to identify potentially hazardous areas, at different scales along the Jordanian Dead Sea coast, from the metric scale (gravimetric approach) to the kilometric one (interferometric approach). To cite this article: D. Closson et al., C. R. Geoscience 335 (2003).  相似文献   

Hydrogeologic characteristics of the alluvial tuff aquifer of northern Sahand Mountain slopes, Tabriz, Iran   总被引：3，自引：0，他引：3  

A. Asghari Moghaddam  M. Allaf Najib 《Hydrogeology Journal》2006,14(7):1319-1329

The Tabriz area is a densely populated area of northwestern Iran (more than 1.5 million in population) with a large proportion of its drinking, domestic, industrial and agricultural water supplied from groundwater resources. The average rate of drinking and industrial water use in the city of Tabriz is about 3.45 m³ s^–1. The Plio-Pleistocene unconfined alluvial tuff aquifer (about 1,275 km²), the most important aquifer in the area, has been known for many years as a reliable resource. The greatest estimated thickness of the alluvial tuff lies in the Saidabad area, with 350 m thickness. There are 994 deep and 284 shallow active pumping wells and 83 qanats operate in the alluvial tuff aquifer. The total water withdrawal from all these artificial discharge points has been measured at 72, 3.8 and 17 million m3/year, respectively. Analytical and numerical methods have been applied to the constant rate pumping test data from the Saidabad wellfield (eight pumping and three observation wells). The values of electrical conductivity in the groundwater of alluvial tuff aquifer range from 203 to 960 μS cm^–1 and bicarbonate type water dominates.  相似文献   

On computation of conditional mean spectrum in Eastern Canada   总被引：2，自引：2，他引：0  

Poulad Daneshvar  Najib Bouaanani  Audrey Godia 《Journal of Seismology》2015,19(2):443-467

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Slip rate on the Dead Sea transform fault in northern Araba valley (Jordan)   总被引：11，自引：0，他引：11  

Y. Klinger  J. P. Avouac  N. Abou Karaki  L. Dorbath  D. Bourles   J. L. Reyss 《Geophysical Journal International》2000,142(3):755-768

The Araba valley lies between the southern tip of the Dead Sea and the Gulf of Aqaba. This depression, blanketed with alluvial and lacustrine deposits, is cut along its entire length by the Dead Sea fault. In many places the fault is well defined by scarps, and evidence for left-lateral strike-slip faulting is abundant. The slip rate on the fault can be constrained from dated geomorphic features displaced by the fault. A large fan at the mouth of Wadi Dahal has been displaced by about 500 m since the bulk of the fanglomerates were deposited 77–140 kyr ago, as dated from cosmogenic isotope analysis (¹⁰Be in chert) of pebbles collected on the fan surface and from the age of transgressive lacustrine sediments capping the fan. Holocene alluvial surfaces are also clearly offset. By correlation with similar surfaces along the Dead Sea lake margin, we propose a chronology for their emplacement. Taken together, our observations suggest an average slip rate over the Late Pleistocene of between 2 and 6 mm yr⁻¹, with a preferred value of 4 mm yr⁻¹. This slip rate is shown to be consistent with other constraints on the kinematics of the Arabian plate, assuming a rotation rate of about 0.396° Myr⁻¹ around a pole at 31.1°N, 26.7°E relative to Africa.  相似文献