2D seismic reflection contribution to structural and geometric study of Cenozoic aquifer systems in the Sisseb El-Alem basin,central-eastern Tunisia     

Ali Souei  Taher Zouaghi 《Arabian Journal of Geosciences》2018,11(21):689

The Sisseb-ElAlem basin in central-eastern Tunisia contains several aquifers intensely used in agriculture. Highly exploited shallow aquifers are vulnerable to pollution and drought and reveal high salinity. Consequently, the new hydrogeological surveys were oriented to deep aquifers. The present work corresponds to study of 2D seismic sections, calibrated by water and petroleum wells, and geological outcrops. It highlights geometry and faulting of buried and preserved structures in depth and leads to identify the spatial distribution of Cenozoic potential reservoir layers in the different paleogeographic domains. The Sisseb-ElAlem basin is affected mainly by near E- and N-trending faults. Iso-depth and iso-thickness mapping were used to follow lateral and vertical variations of sedimentary series related to tectonics. The study area consists of Sisseb, Sbikha and El Ktifa uplifts, and El Alem, and Bled Saadia subsiding synclines. The Oligocene-Miocene reservoir series are exploited locally at the high borders. They reveal thickening and deepening southward in the El Alem-Bled Saadia domain, where they can be exploited at about 400 to 2000 m depths.This study should contribute to the orientation of water research to deeper aquifers, and therefore, ensure sufficient drinking and irrigation water supply mainly in areas called for sustainable development.  相似文献   

Investigation of monotonic and cyclic behavior of sand using a bounding surface plasticity model     

Ali Zahmatkesh  Reza Noorzad 《Arabian Journal of Geosciences》2018,11(2):40

Developing the pore water pressures in loose to medium sands below the water table may lead to liquefaction during earthquakes. The simulation of liquefaction (cyclic mobility and flow liquefaction) in sandy soils is one of the major challenges in constitutive modeling of soils. This paper presents the simulation of sand behavior using a critical state bounding surface plasticity model (Dafalias and Manzari’s model, 2004) during monotonic and cyclic loading. The drained, undrained, and cyclic triaxial tests were simulated using Dafalias and Manzari’s model. The simulation results showed that the model predicts behavior of sand, reasonably well. Also, for CSR?<?0.2, number of cycles for liquefaction is significantly increased. The residual strength of Babolsar sand is produced when it is deformed to an axial strain of 20 to 25%.  相似文献   

Characterization of aerosol type based on aerosol optical properties over Baghdad,Iraq     

Ali M. Al-Salihi 《Arabian Journal of Geosciences》2018,11(20):633

Aerosol optical depth (AOD), Angstrom exponent (AE), and ozone monitoring instrument aerosols index (OMI-AI) data, derived from MODerate Resolution Imaging Spectroradiometer (MODIS) and OMI sensor on board NASA’s Aqua satellite and NASA-Aura satellite platforms, have been analyzed and classified over Baghdad, Iraq, for an 8-year period (2008–2015). In order to give an obvious understanding of temporal inconsistency in the characteristics and classification of aerosols during each season separately, PREDE POM-02 sky radiometer measurements of AOD, carried out during a 2-year period (2014–2015), were compared with MODIS–Aqua AODs. On seasonal bases, MODIS–Aqua AODs corroborate well with ground-based measurements, with correlation coefficients ranging between 0.74 and 0.8 and RMSE ranging from 0.097 to 0.062 during spring and autumn seasons respectively. The overall satellite- and ground-based measurement comparisons showed a good agreement with correlation coefficients of 0.78 and RMSE of 0.066. These results suggest that MODIS–Aqua gives a good estimate of AOD. Analysis of MODIS–Aqua data for the 8-year period showed that the overall mean AOD, AE, and OMI-AI over Baghdad were 0.44?±?0.16, 0.77?±?0.29, and 1.34?±?0.33 respectively. AOD records presented a unique peak which was extended from mid-spring (April) to mid-summer (July) while the AE annual variability indicated a more complicated behavior with minimum values during the period from late spring (May) to early autumn (September). The maximum AOD and OMI-AI values occurred during summer while their minimum values occurred during winter. The AE showed an opposite behavior to that of AOD such that the highest AE values occurred during autumn and winter and the lowest values happened during spring and summer. This behavior may be attributed to the domination of coarse aerosol particles during autumn and winter seasons and fine aerosol particles during spring and summer seasons. A Hybrid Single-Particle Lagrangian Integrated Trajectory model was utilized to determine the source of air mass transport and to recognize the variability of aerosol origin regions. Finally, AOD, AE, and OMI-AI values have been employed to identify several aerosol types and to present seasonal heterogeneity in their contribution based on their origins.  相似文献   

Synthesis of biochar from sugarcane filter-cake and its impacts on physiological performance of lettuce (<Emphasis Type="Italic">Lettuce sativa</Emphasis>) grown on cadmium contaminated soil     

Anum Sehar  Rukhsanda Aziz  Muhammad Tariq Rafiq  Muhammad Mazhar Hussain  Muhammad Rizwan  Adiba Khan Sehrish  Muhammad Khalid Rafiq  Jalal ud Din  Qaiser Hussain  Mohammad I. Al-Wabel  Shafaqat Ali 《Arabian Journal of Geosciences》2018,11(20):634

Soil contamination with cadmium has become major concern all over the world because of its adverse impacts on ecosystem health and agricultural land. Soil amendment with biochar may have varied effects on physical and chemical properties of soil. The objective of the study was to explore the impact of sugarcane filter-cake biochar on physiological performance and growth of lettuce in an aged soil. Four different doses (0, 1.5%, 3%, and 5%) of biochar were used in the soil and conditioned for 1 month. After this, lettuce seedlings were grown in the soil. The results showed that the biochar treatment improved the fresh and dry biomass of leaves and roots as well as plant height while diminished the bioavailability of cadmium from the soil. As compared to control, biochar significantly enhanced the chlorophyll content in lettuce leaves. Due to the biochar amendment, the oxidative stress decreased in lettuce shoots over the control. As compared to control, concentration of cadmium in lettuce significantly decreased after the application of biochar. It was concluded that biochar could mitigate the toxicity of cadmium in lettuce by altering the biochemical and physiological processes in cadmium contaminated soil.  相似文献   

Green synthesis of magnetic mesoporous silica nanocomposite and its adsorptive performance against organochlorine pesticides     

W. A. El-Said  D. M. Fouad  M. H. Ali  M. A. El-Gahami 《International Journal of Environmental Science and Technology》2018,15(8):1731-1744

Green synthesis of nanomaterials has received increasing attention as an eco-friendly technology in materials science. Here, we have used two types of extractions from green tea leaf (i.e., total extraction and tannin extraction) as reducing agents for a rapid, simple and one-step synthesis method of mesoporous silica nanoparticles/iron oxide nanocomposite based on deposition of iron oxide onto mesoporous silica nanoparticles. Mesoporous silica nanoparticles/iron oxide nanocomposite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, vibrating sample magnetometer, N₂ adsorption and high-resolution transmission electron microscopy. Mesoporous silica nanoparticles/iron oxide nanocomposite was used as a solid adsorbent for removal of lindane pesticide from aqueous solutions. The developed system possesses the advantages of silica as core that include large surface area and advantages of iron oxide (shell) that include the capability to interact with chlorinated compounds and ability to release by using external magnetic field. UV-Vis technique was used as a simple and easy method for monitoring the removal of lindane. Effects of pH and temperature on the removal efficiency of the developed mesoporous silica nanoparticles/iron oxide nanocomposite toward lindane pesticide were also investigated. Fourier transform infrared spectroscopy, high-performance liquid chromatography and gas chromatography techniques were used to confirm the high ability of mesoporous silica nanoparticles/iron oxide nanocomposite for sensing and the capture of lindane molecules with high sorption capacity (about 99%) that could develop a new eco-friendly strategy for detection and removal of pesticide and as a promising material for water treatment.  相似文献   

Development of an efficient surrogate model based on aquifer dimensions to prevent seawater intrusion in anisotropic coastal aquifers,case study: the Qom aquifer in Iran     

Ali Ranjbar  Najmeh Mahjouri 《Environmental Earth Sciences》2018,77(11):418

Coastal aquifers are usually exposed to saltwater intrusion. Therefore, groundwater extracted from these aquifers should be regulated considering their dimensions and effective parameters. In this paper, optimum discharge from a large number of exploitation wells is evaluated according to variations of width, length, and anisotropy coefficient in the Qom aquifer near the salt lake in central Iran. First, the wells are divided into clusters to decrease the number of decision variables. Then, the location and discharge from each cluster is obtained using SEAWAT and charged system search (CSS) simulation–optimization model with the assumption of three-dimensional variable density flow. The maximum discharge considering various anisotropy rates is computed based on different values of lengths and widths of the aquifer. Finally, an M5-tree model is trained using the obtained samples to derive a linear relationship between input and output data. Based on the results, for various ranges of width and length of an aquifer with impermeable boundaries, different linear equations for optimum discharge are obtained. Also, it was found that for an aquifer with a small width, the critical discharge is a function of the length while the effect of the boundaries is negligible. Sensitivity analysis of the anisotropy coefficient reveals that with increasing the anisotropy rate, thickness and slope of the transition zone decrease and as the maximum discharge increases consequently. However, the sensitivity of the discharge to anisotropy rate is not remarkable. A comparison between the results of this study with those of the analytical method based on sharp interface assumption is carried out. For the critical condition, the best agreement between analytical equation (\(\overline {L} =0.87\overline {W} +0.62\)) and proposed method (\(\overline {L} =0.83\overline {W} - 1.41\)) is achieved for the anisotropic aquifer when the 50% isochlor is assumed as the measure of salt water intrusion.  相似文献   

Chemical composition of rock-forming minerals and crystallization physicochemical conditions of the Middle Eocene I-type Haji Abad pluton,SW Buin-Zahra,Iran     

Kazem Kazemi  Ali Kananian  Yilin Xiao  Fatemeh Sarjoughian 《Arabian Journal of Geosciences》2018,11(22):717

The Haji Abad intrusion is a well-exposed Middle Eocene I-type granodioritc pluton in the Urumieh–Dokhtar magmatic assemblage (UDMA). The major constituents of the investigated rocks are K-feldspar, quartz, plagioclase, pyroxene, and minor Fe–Ti oxide and hornblende. The plagioclase compositions fall in the labradorite, andesine, and oligoclase fields. The amphiboles range in composition from magnesio-hornblende to tremolite–hornblende of the calcic-amphibole group. Most pyroxenes principally plot in the field of diopside. The calculated average pressure of emplacement is 1.9 kbar for the granodioritic rocks, crystallizing at depths of about 6.7 km. The highest pressure estimated from clinopyroxene geobarometry (5 kbar) reflects initial pyroxene crystallization pressure, indicating initial crystallization depth (17.5 km) in the Haji Abad granodiorite. The estimated temperatures using two-feldspar thermometry give an average 724 °C. The calculated average temperature for clinopyroxene crystallization is 1090 °C. The pyroxene temperatures are higher than the estimated temperature by feldspar thermometry, indicating that the pyroxene and feldspar temperatures represent the first and late stages of magmatic crystallization of Haji Abad granodiorite, respectively. Most pyroxenes plot above the line of Fe³⁺?=?0, indicating they crystallized under relatively high oxygen fugacity or oxidized conditions. Furthermore, the results show that the Middle Eocene granitoids crystallized from magmas with H₂O content about 3.2 wt%. The relatively high water content is consistent with the generation environment of HAG rocks in an active continental margin and has allowed the magma to reach shallower crustal levels. The MMEs with ellipsoidal and spherical shapes show igneous microgranular textures and chilled margins, probably indicating the presence of magma mixing. Besides, core to rim compositional oscillations (An and FeO) for the plagioclase crystals serve as robust evidence to support magma mixing. The studied amphiboles and pyroxenes are grouped in the subalkaline fields that are consistent with crystallization from I-type calc-alkaine magma in the subduction environment related to active continental margin. Mineral chemistry data indicate that Haji Abad granodiorites were generated in an orogenic belt related to the volcanic arc setting consistent with the subduction of Neo-Tethyan oceanic crust beneath the central Iranian microcontinent.  相似文献   

Structural properties of Urfa stone doped with erbium oxide     

Bulent Aktas  Serife Yalcin  Mehmet Albaskara  Ali Arslan  Gokhan Ceyhan 《Arabian Journal of Geosciences》2018,11(23):757

In this study, we investigated the structural properties of Urfa stone (US) doped with erbium oxide (Er₂O₃). Solid US was powdered by using an agate mortar, and its elemental composition was determined using inductive coupling plasma (ICP) methods. Varying amounts of Er₂O₃ (5, 10, 20, 30, and 40%) were added as a dopant to the US powder using mechanical alloying methods. The resultant samples were sintered at 1000 °C for 1 h. The structural properties of the Er₂O₃-doped US samples were subsequently investigated using X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and photoluminescence methods. Results from the XRD analysis of the Er₂O₃-doped US powder indicated two crystalline phases: (1) calcium oxide (CaO) or lime and (2) Er₂O₃. After the samples were sintered at 1000 °C, CaO, Er₂O₃, calcium carbonate (CaCO₃), and mixed crystalline phases were observed. Results from the FTIR analysis of the Er₂O₃-doped US samples indicated absorption bands at 711.91, 872.08, and 1396.87 cm^?1 in the spectra. Finally, photoluminescence analysis results indicated a shift in the emission and excitation bands to longer and shorter wavelengths, respectively, in the solid state (non-aqueous media) US-Er complex.  相似文献   

The measurement of soil gases and shallow temperature for determination of active faults in a geothermal area: a case study from Ömer–Gecek,Afyonkarahisar (West Anatolia)     

Ahmet Yıldız  Can Başaran  Metin Bağcı  Ayla Gümüş  Feyzullah Ekrem Çonkar  Yusuf Ulutürk  Hüseyin Ali Yalım 《Arabian Journal of Geosciences》2018,11(8):175

Afyonkarahisar is a very important geothermal province of western Anatolia and has low and medium enthalpy geothermal areas. This study has been carried out for the preparation of distribution maps of soil gases (radon and carbon dioxide) and shallow soil temperature and the exploration of permeable tectonic regions associated with geothermal systems and reveal the origins of radon and carbon dioxide gases. The western district of the study area is characterized by the high radon concentration (168.30 kBq/m³), carbon dioxide ratio (0.30%), and soil temperature (21.0 °C) values. Fethibey and Demirçevre faults, which allow the circulation of geothermal fluids, have been detected in the distribution maps of radon, carbon dioxide, and shallow depth temperature and the directions of the curves in these maps correspond to the strikes of Demirçevre faults. The effect of the fault plays an important role in the change of carbon dioxide concentration along the W-E directional geological section prepared to determine the change of soil gas and shallow depth temperature values depending on lithological differences, fault existence, and geothermal reservoir depth. On the other hand, it was determined that Rn²²² concentration and soil temperature changed as a function of geothermal reservoir depth or lithological difference. Tuffs in Köprülü volcano-sedimentary units are the main source of radon due to their higher uranium contents. Besides, the carbon dioxide in Ömer–Gecek soils has geothermal origin because of the highest carbon dioxide content (99.3%) in non-condense gas. The similarities in patterns of soil temperature, radon, and carbon dioxide indicate that the variation in soil temperatures is related to radon and carbon dioxide emissions. It is concluded that soil gas and temperature measurements can be used to determine the active faults in the initial stage of geothermal exploration successfully.  相似文献   

基于全球及区域气候模式的江苏省降水变化趋势预估          下载免费PDF全文

李熠  买苗 《大气科学学报》2019,42(3):447-458

利用气象观测资料,8个全球耦合气候系统模式的集合平均以及区域气候模式(RegCM4)的结果,通过方差分析、相关分析、趋势分析、扰动法等方法对模式性能进行了评估,并对江苏省在未来RCP8.5高端排放情景下降水的变化趋势进行了预估。结果表明,在RCP8.5情景下,至2020、2030和2050年,全球模式模拟的江苏省年平均降水在未来有逐渐增加的趋势,线性增加率约为7 mm/(10 a)。至2050年,江苏省年平均降水量将增加2%左右;区域模式模拟的年平均降水在未来线性增加率为1.5 mm/(10 a),变化不显著。区域模式模拟的夏季降水在未来有所增加,最多可增加20%～30%,但增幅随时间逐渐减小;全球模式模拟的夏季降水比现在有所减少,至2050年,减少了大约10%。区域模式模拟的冬季降水在未来不同时间段均比现在有所减少,同现在相比,最多可减少30%～40%;而全球模式模拟的冬季降水在未来则是先减少,后增加,至2050年,比现在大约增加10%。对于不同季节,总体而言,南部地区降水量的变化较北部地区显著。对于极端降水事件来说,江苏省未来小雨日数将减少,而暴雨日数则微弱增加。但由于全球模式本身的性能、区域模式对全球模式的依赖性以及温室气体排放的不确定性使上述预估结果仍具有不确定性。  相似文献