Analyse sismo-stratigraphique du bassin d'Abda (Maroc occidental), exemple de structures inverses pendant le rifting atlantiqueSeismo-stratigraphic analysis of the Abda Basin (West Morocco): a case of reverse structures during the Atlantic rifting     

Hassan Echarfaoui  Mohamed Hafid  Abdallah Aı̈t Salem  Aı̈t Fora Abderrahmane 《Comptes Rendus Geoscience》2002,334(6):371-377

The review of the seismic reflection and well data from the coastal Abda Basin (western Morocco) shows that its Triassic and Jurassic sequences were deposited in a submeridean sag basin, whose eastern margin is characterised by progressive truncations and pinching out of these sequences against a prominent Palaeozoic high. The uplift of this latter is interpreted as a response to an Upper Triassic–Middle Jurassic local compressional event that controlled Triassic–Jurassic sedimentation within the Abda Basin. The present day ‘West Meseta Flexure’ is a surface expression of this uplift. To cite this article: H. Echarfaoui et al., C. R. Geoscience 334 (2002) 371–377.  相似文献   

The Northern end of the Dead Sea Basin: Geometry from reflection seismic evidence   总被引：2，自引：1，他引：2  

Abdallah S. Al-Zoubi  Till Heinrichs  Isam Qabbani  Uri S. ten-Brink 《Tectonophysics》2007,434(1-4):55-69

Recently released reflection seismic lines from the Eastern side of the Jordan River north of the Dead Sea were interpreted by using borehole data and incorporated with the previously published seismic lines of the eastern side of the Jordan River. For the first time, the lines from the eastern side of the Jordan River were combined with the published reflection seismic lines from the western side of the Jordan River. In the complete cross sections, the inner deep basin is strongly asymmetric toward the Jericho Fault supporting the interpretation of this segment of the fault as the long-lived and presently active part of the Dead Sea Transform. There is no indication for a shift of the depocenter toward a hypothetical eastern major fault with time, as recently suggested. Rather, the north-eastern margin of the deep basin takes the form of a large flexure, modestly faulted. In the N–S-section along its depocenter, the floor of the basin at its northern end appears to deepen continuously by roughly 0.5 km over 10 km distance, without evidence of a transverse fault. The asymmetric and gently-dipping shape of the basin can be explained by models in which the basin is located outside the area of overlap between en-echelon strike-slip faults.  相似文献   

A Tortonian onset for the Algerian margin inversion: Evidence from low‐temperature thermochronology     

Alice Recanati  Yves Missenard  Rmi Leprêtre  Ccile Gautheron  Jocelyn Barbarand  Fatiha Abbassene  Nachida Abdallah  Aziouz Ouabadi  Mohamed El Messaoud Derder  Claire Boukari  Rosella Pinna‐Jamme  Frdric Haurine 《地学学报》2019,31(1):39-48

In North Africa, the Algerian margin is made of basement blocks that drifted away from the European margin, namely the Kabylia, and docked to the African continental crust in the Early Miocene. This young margin is now inverted, as dated Miocene (17 Ma) granites outcrop alongshore, evidencing kilometre‐scale exhumation since their emplacement. Age of inversion is actually unknown, although Pliocene is often considered in the offshore domain. To decipher the exhumation history of the margin between 17 and 5 Ma, we performed a coupled apatite fission track (AFT) and (U–Th–Sm)/He (AHe) study in the Cap Bougaroun Miocene granite. AFT dates range between 7 ± 1 and 10 ± 1 Ma, and mean AHe dates between 8 ± 2 and 10 ± 1 Ma. These data evidence rapid and multi‐kilometre exhumation during Tortonian times. This event cannot be related to slab break‐off but instead to the onset of margin inversion that has since developed as an in‐sequence north‐verging deforming prism.  相似文献   

The Quaternary development of tributary channels to the Nile River at Kom Ombo area,Eastern Desert of Egypt,and their implication for groundwater resources     

Mohammed El Bastawesy  Abdallah Faid  El Sayed El Gammal 《水文研究》2010,24(13):1856-1865

The dry wadis ‘ephemeral channel’ constituting the main tributaries to the Nile River in Kom Ombo are structurally and tectonically controlled and exhibit complex drainage pattern. This complicated drainage pattern is inherited from the morpho‐tectonic evolution of the ancestral Nile River (‘Protonile’), which drained the Eastern Desert during the Middle Pleistocene. A digital elevation model derived from Shuttle Radar Topography Mission data is used to delineate the contemporary drainage networks and their catchments. Satellite images acquired during a flash flood event were used to validate the delineated watershed divides and flow pathways, particularly where the courses of dry wadis are interlocked. Currently, the westward flow of Wadi Abu‐Suberah is derived from a small area in the Eastern Desert, as the palaeo‐upper reaches of this wadi were captured due to tectonic movements along NW/SE and N/S faults by wadis in the Kharit and Elewa areas. The influence of these tectonic movements on groundwater distribution is also shown where the deep Nubian aquifer discharges its water into the Quaternary aquifer through fault planes. The northward flowing ‘Protonile’ main course has tectonically shifted from the Gallaba plain in the Western Desert, eastward to the current Nile River course. This shift has produced several cut‐off segments of the palaeo‐tributary drainage that was originally flowing westward towards the old ‘Protonile’ main course in the Gallaba plain. However, these segments have reversed their surface run‐off flow directions eastward towards the current Nile course; they could include potential groundwater resources, as their alluvium may be still recharged by the Nile River. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Reply to Comment on “The Keisarhjelmen detachment records Silurian–Devonian extensional collapse in Northern Svalbard”          下载免费PDF全文

Alvar Braathen  Per Terje Osmundsen  Harmon Maher  Morgan Ganerød 《地学学报》2018,30(4):322-324

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Fluid geochemistry of natural manifestations from the Southern Poroto–Rungwe hydrothermal system (Tanzania): Preliminary conceptual model     

Manuëlla Delalande  Laurent Bergonzini  Fabrizio Gherardi  Massimo Guidi  Luc Andre  Issah Abdallah  David Williamson 《Journal of Volcanology and Geothermal Research》2011,199(1-2):127-141

The South Poroto–Rungwe geothermal field, in the northern part of the Malawi rift, Tanzania divides in two main areas. The relatively high altitude northern area around the main Ngozi, Rungwe, Tukuyu and Kyejo volcanoes, is characterised by cold and gas-rich springs. In contrast, hot springs occur in the southern and low-altitude area between the Kyela and Livingstone faults. The isotopic signature of the almost stagnant, cold springs of the Northern district is clearly influenced by H₂O–CO_2(g) exchange as evidenced from negative oxygen-shifts in the order of few deltas permil. In contrast, the isotopic signature of waters discharged from the hot springs of the Southern district is markedly less affected by the H₂O–CO_2(g) interaction. This evidence is interpreted as an effect of the large, permanent outflow of these springs, which supports the hypothesis of a regional-scale recharge of the major thermal springs. Measurements of carbon isotope variations of the dissolved inorganic carbon of waters and CO_2(g) from the Northern and Southern springs support a model of CO_2(g)-driven reactivity all over the investigated area. Our combined chemical and isotopic results show that the composition of hot springs is consistent with a mixing between (i) cold surface fresh (SFW) and (ii) Deep Hot Mineralised (DHMW) Water, indicating that the deep-originated fluids also supply most of the aqueous species dissolved in the surface waters used as local potable water. Based on geothermometric approaches, the temperature of the deep hydrothermal system has been estimated to be higher than 110 °C up to 185 °C, in agreement with the geological and thermal setting of the Malawi rift basin. Geochemical data point to (i) a major upflow zone of geothermal fluids mixed with shallow meteoric waters in the Southern part of the province, and (ii) gas absorption phenomena in the small, perched aquifers of the Northern volcanic highlands.  相似文献   

Intraurban variability of PM10 and PM2.5 in an Eastern Mediterranean city     

Rawad Massoud  Alan.L Shihadeh  Mohamed Roumié  Myriam Youness  Jocelyne Gerard  Nada Saliba  Rita Zaarour  Maher Abboud  Wehbeh Farah  Najat Aoun Saliba 《Atmospheric Research》2011,101(4):893-901

The results of the first large scale chemical characterization of PM10 and PM2.5 at three different sites in the urban city of Beirut, Lebanon, are presented. Between May 2009 and April 2010 a total of 304 PM10 and PM2.5 samples were collected by sampling every sixth day at three different sites in Beirut. Observed mass concentrations varied between 19.7 and 521.2 μg m^? 3 for PM10 and between 8.4 and 72.2 μg m^? 3 for PM2.5, respectively. Inorganic concentrations accounted for 29.7–35.6 μg m^? 3 and 46.0–53.5 μg m^? 3 of the total mass of PM10 and PM2.5, respectively. Intra-city temporal and spatial variations were assessed based on the study of three factors: correlation coefficients (R) for PM and chemical components, coefficient of divergence (CODs), and source apportionment using positive matrix factorization (PMF). Based on R and COD of PM concentrations, the three sites appear homogeneous. However, when individual elements were compared, heterogeneity among sites was found. This latter was attributed to the variability in the percent contribution of biogenic and local anthropogenic source factors such as traffic related sources and dust resuspension. Other factors included the proximity to the Mediterranean sea, the population density and the topographical structure of the city. Hence, despite its small size (20.8 km²), one PM monitoring site does not reflect an accurate PM level in Beirut.  相似文献   

TEM study of the geoelectrical structure and groundwater salinity of the Nahal Hever sinkhole site, Dead Sea shore, Israel   总被引：1，自引：0，他引：1  

Michael Ezersky  Anatoly Legchenko  Abdallah Al-Zoubi  Eldad Levi 《Journal of Applied Geophysics》2011,75(1):99-112

Since the 1990s a large number of sinkholes have appeared in the Dead Sea (DS) coastal area. Sinkhole development was triggered by the lowering of the DS level. In the literature the relationship between the sinkholes and the DS level is explained by intrusion of relatively fresh water into the aquifer thereby dramatically accelerating the salt dissolution with creation of subsurface caverns, which in turn cause sinkholes. The main goal of our project was detection and localization of relatively fresh groundwater. During our study we used the transient electromagnetic method (TEM) to measure the electrical resistivity of the subsurface. As a test site we selected Nahal Hever South which is typical for the DS coast. Our results show that resistivity of the shallow subsurface reflects its vertical and lateral structure, e.g., its main hydrogeological elements explain the inter-relations between geology, hydrogeology, and sinkholes. The TEM method has allowed detailed differentiation of layers (clay, salt, etc.) in the subsurface based on their bulk resistivity. The 10 m-thick salt layer composed of idiomorphic crystals of halite deposited during the earlier Holocene period was extrapolated from borehole HS-2 through the study area. It was found that in Nahal Hever the typical value of the bulk resistivity of clay saturated with the DS brine varies between 0.2 and 0.3 Ωm, whereas saturated gravel and sandy sediments are characterized by resistivity between 0.4 and 0.6 Ωm. The high water salinity of the aquifer (enveloping the salt layer) expressed in terms of resistivity is also an important characterization of the sinkhole development mechanism. The electrical resistivity of the aquifer in the vicinity of the salt unit and its western border did not exceed 1 Ωm (in most cases aquifer resistivity was 0.2-0.6 Ωm) proving that, in accordance with existing criteria, the pores of the alluvial sediments are filled with highly mineralized DS brine. However, we suggest that the criterion of the aquifer resistivity responsible for the salt dissolution should be decreased from 1 Ωm to 0.6 Ωm corresponding to the chloride concentration of approximately 100 g/l (the chloride saturation condition reaches 224 g/l in the northern DS basin and 280 g/l in the southern one).Based on TEM results we can reliably conclude that in 2005, when most of sinkholes had appeared at the surface, salt was located within a very low resistivity environment inside sediments saturated with DS brine. Intrusion of relatively fresh groundwater into the aquifer through the 600 × 600 m²area affected by sinkholes has not been observed.  相似文献   

Inorganic arsenic in marine organisms     

W.A. Maher 《Marine pollution bulletin》1983,14(8):308-310

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Advanced Mathematical Models to Predict the Compaction Properties of Coarse-Grained Soils from Various Physical Properties     

Maher Omar  Abdallah Shanableh  Mohamed Arab  Khaled Hamad  Ali Tahmaz 《Geotechnical and Geological Engineering》2018,36(6):3467-3483

An essential task in the process of construction is the determination of compaction properties of soils. Many years of laboratory test experience strengthen our belief in the existence of predictive equations that govern the compaction characteristics of soils. An advanced mathematical model developed in this research in order to uncertain the governing equations. An advanced mathematical model developed in this research in order to uncertain the governing equations. Through a comparative study among a Multiple Linear Regression (MLR) model, an Artificial Neural Network (ANN) model, Extreme Learning Machine (ELM) and a Support Vector Machine (SVM) model, the best predicting model was determined. For this purpose, Six hundred and six (606) samples collected and split into a dataset used for training the models and another used for validation of the derived model. 8 neural networks with a varying number of hidden layers and a varying number of nodes in hidden layers were employed. In ELM 1 hidden layer with varying number of units were employed. It was found that the equations derived from the ELM models described the relationship with superiority over multiple regression, ANN and SVM models for Maximum Dry Density and MLR models described the relationship with superiority over ANN, ELM and SVM models for Optimum Moisture Content.  相似文献