Geochemical and isotopic evolution of groundwater in the Wadi Watir watershed,Sinai Peninsula,Egypt     

Mustafa A. Eissa  James M. Thomas  Ronald L. Hershey  Maher I. Dawoud  Greg Pohll  Kamal A. Dahab  Mohamed A. Gomaa  Ashraf R. Shabana 《Environmental Earth Sciences》2014,71(4):1855-1869

The Wadi Watir delta in the Wadi Watir watershed is a tourist area in the arid southeastern part of the Sinai Peninsula, Egypt, where development and growth of the community on the delta are constrained by the amount of groundwater that can be withdrawn sustainably. To effectively manage groundwater resources in the Wadi Watir delta, the origin of groundwater recharge, groundwater age, and changes in groundwater chemistry in the watershed needs to be understood. Mineral identification, rock chemistry, water chemistry, and the isotopes of hydrogen, oxygen, and carbon in groundwater were used to identify the sources, mixing, and ages of groundwater in the watershed and the chemical evolution of groundwater as it flows from the upland areas in the watershed to the developed areas at the Wadi Watir delta. Groundwater in the Wadi Watir watershed is primarily from recent recharge while groundwater salinity is controlled by mixing of chemically different waters and dissolution of minerals and salts in the aquifers. The El Shiekh Attia and Wadi El Ain areas in the upper Wadi Watir watershed have different recharge sources, either from recharge from other areas or from different storm events. The downgradient Main Channel area receives groundwater flow primarily from the El Shiekh Attia area. Groundwater in the Main Channel area is the primary source of groundwater supplying the aquifers of the Wadi Watir delta.  相似文献   

Geology and geochemistry of Kurkur bentonites,southern Egypt: provenance,depositional environment,and compositional implication of Paleocene–Eocene thermal maximum     

Kamal Abou Elmagd  Mohamed Wahbi Ali-Bik  Salwa Dahab Abayazeed 《Arabian Journal of Geosciences》2014,7(3):899-916

A large lower Eocene bentonite deposit at the top of Sinn El-Kaddab plateau, southern Egypt, is investigated. It forms isolated anticlinal hills as mesa and cuesta geomorphic units. The Sinn El-Kaddab plateau (497 m above sea level) with Gebel Abyad in northern Sudan represent the most southern margin of Tethys realm in East Africa. Clay and silt fractions constitute up to 95 % of the bentonite and calcium montmorillonite is the predominant phase (70–87 %). These sediments were deposited during the Paleocene–Eocene Thermal Maximum (PETM) event. Grain-size distribution in conjunction with their geologic setting argues in favor of a low energy deep hemipelagic, restricted basin within the outer shelf zone. They suggest sporadic deposition in a basin characterized by relief oscillation, in response to continuous tectonic uplifting. The sediments of the peripheral parts of the basin are more calcareous and were deposited in an arid climatic condition. Calcium montmorillonite was deposited in subtropical warm climate, with alternating wet and dry seasons. Compositionally, the bentonite shales are basic to intermediate and exhibit a rather limited range of K₂O/Na₂O and SiO₂/Al₂O₃ ratios. They suggest mature polycyclic siliciclastics as the main provenance and within-plate alkali basalts as a main igneous precursor. They are the product of intensive physical weathering process in response to combined effects of both tectonic disturbance and prevailed climatic conditions during the PETM event. Geochemically, they are interpreted in terms of mixing of two end-members: pure clastic terrigenous component (inherited from the source area) and carbonate-rich matrix.  相似文献   

An index to assess the propensity of landfall in Australia of a tropical cyclone     

Kamal K. Saha  Saleh A. Wasimi 《Natural Hazards》2014,72(2):1111-1121

Every year, Australian oceans experience the genesis of many tropical cyclones (TCs). About 40 percent of these make landfall. Because of the enormous difference in impacts between landfalling and non-landfalling TCs on coastal communities, the benefits would be enormous if it were possible to capture early the potentiality of landfall of a TC that has undergone genesis. Published literature identifies many factors such as location, warm sea surface temperature above 26 °C, conditional instability and high relative humidity in the middle troposphere and low vertical wind shear for the genesis of cyclones. Some of these factors could hold information about the potentiality of landfall while a TC is forming. An investigation into these factors actually revealed that a landfall potential index can be developed that can capture the potentiality of making a landfall. An attractive feature of this index is that it uses values at the time and location of genesis, providing a long and useful lead time. Furthermore, it is made into a dimensionless number, which makes for easy comprehension and interpretation.  相似文献   

Liquefaction resistance evaluation of soils using artificial neural network for Dhaka City,Bangladesh     

Fahim  Abul Kashem Faruki  Rahman  Md. Zillur  Hossain  Md. Shakhawat  Kamal  A. S. M. Maksud 《Natural Hazards》2022,113(2):933-963

Natural Hazards - Soil liquefaction resistance evaluation is an important site investigation for seismically active areas. To minimize the loss of life and property, liquefaction hazard analysis is...  相似文献   

A new look on Imperial Porphyry: a famous ancient dimension stone from the Eastern Desert of Egypt—petrogenesis and cultural relevance     

Abu El-Enen  Mahrous M.  Lorenz  Joachim  Ali  Kamal A.  von Seckendorff  Volker  Okrusch  Martin  Schüssler  Ulrich  Brätz  Helene  Schmitt  Ralf-Thomas 《International Journal of Earth Sciences》2018,107(7):2393-2408

International Journal of Earth Sciences - Imperial Porphyry, a famous dimension stone of spectacular purple color, was quarried in the Mons Porphyrites area north of Jabal Dokhan in the Eastern...  相似文献   

Magnetic and seismic refraction survey for site investigation of an urban expansion site in Abha District,Southwest Saudi Arabia     

Almadani  Sattam  Ibrahim  Elkhedr  Abdelrahman  Kamal  Al-Bassam  Abdulaziz  Al-Shmrani  Awad 《Arabian Journal of Geosciences》2015,8(4):2299-2312

Arabian Journal of Geosciences - Ground magnetic and seismic refraction survey is carried out on an urban extension site in the southwest of Ahud Rufeidah town, southwest Saudi Arabia. The purpose...  相似文献   

Influence of natural and anthropogenic factors on the water quality of the coastal waters around the South Andaman in the Bay of Bengal     

Renjith VishnuRadhan  Divya David Thresyamma  Kamal Sarma  Grinson George  Prabhakar Shirodkar  Ponnumony Vethamony 《Natural Hazards》2015,78(1):309-331

During the last decade, the Andaman and Nicobar Islands (ANI) have witnessed a marginal population growth with associated variations and degradation in the water quality of the inhabited coastal region. Monthly water quality data collected from six coastal locations in ANI were used to evaluate the anthropogenic influence in an otherwise pristine island environment. Exceptionally low dissolved oxygen (0.7–2.0 mg/L) at the Phoenix Jetty (PJ) and mangrove site indicates hypoxic conditions. Among the nutrients, nitrate shows high values at PJ due to heavy nutrient loading from domestic sewage. The cluster analysis segregated PJ from the remaining sites, indicating deterioration in the water quality. On the other hand, water quality at Sippighat, a low-intensity aquaculture site, does not indicate any deterioration. Apart from the large modulations in the water quality of the study area by the Bay of Bengal waters, the effect of domestic waste discharges significantly affects the coastal waters of Andaman. Though the present water quality at most of the study sites appears acceptable, the increased volume of tourism and allied activities poses a potential threat to the island ecosystem. Besides the anthropogenic influences, the long-term trends in oceanographic factors were analyzed in order to decipher the expected natural effect on future water quality of the region. Based on the increasing sea surface temperature as well as the decreasing chlorophyll-a, eddy kinetic energy, and zonal kinetic energy, we propose that the combined effect of both natural and anthropogenic factors can ultimately distress the present ambient water quality of ANI.  相似文献   

Finite larmor-radius effects on Rayleigh-Taylor instability of a dusty magnetized plasma     

Raj Kamal Sanghvi  R. K. Chhajlani 《Astrophysics and Space Science》1987,132(1):57-64

This paper discusses the Rayleigh-Taylor (RT) instability of an infinitely conducting medium having an exponential density distribution which includes the effects of finite ion Larmor-radius (FLR) corrections and suspended particles in the presence of a uniform horizontal magnetic field. The relevant equations of the problem are linearized and from the linearized perturbation equations a dispersion relation is obtained, using appropriate boundary conditions. It has been found that the criterion for the stable density stratification remains uninfluenced by the simultaneous inclusion of the FLR corrections and suspended particles. The stability of the medium has been proved for the case of stable stratification when the FLR corrections are not considered in the analysis. The growth rate of unstable RT modes with increasing relaxation frequency of the suspended particles is evaluated analytically. It has been shown that the presence of suspended particles in the medium suppresses the growth rate of the unstable RT modes, thereby implying a stabilizing influence of the particles on the considered configuration.  相似文献   

Optimal estimation of ship's attitudes for beampattern corrections in a coaxial circular array     

Bishwajit Chakraborty  Kamal K. Dey 《Marine Geodesy》2013,36(4):223-236

A study is conducted to estimate the accurate attitude of a ship's motion and the estimation is used to arrive at the corrections required for a farfield pattern of a coaxial circular array. The relevant analytical expression is developed for the computation of moving average filter weights to estimate the ship's attitude for beamsteerings at different sea conditions. Farfield patterns are presented for different steered directions for the coaxial circular array of the additive type, and the multiplicative array technique is also used for beamsteering for higher steering angles to observe its control on the sidelobes as well as for the main beamwidths. In order to introduce an adaptive filter to estimate the accurate attitude for stable sonar platform, an adaptive parameter is examined for bathymetric applications where nonstationary ship movement prevails.  相似文献   

Groundwater exploration using remote sensing and geographic information systems in a semi-arid area (Southwest of Urmieh, Northwest of Iran)     

Kamal Khodaei  Hamid Reza Nassery 《Arabian Journal of Geosciences》2013,6(4):1229-1240

Shortage of water required for drinking and agricultural uses is a subject with a vital importance in most arid and semi-arid regions. The area of this study is one of the semi-arid regions located in southwest of Urmieh lake, northwest of Iran, between N 37°00′, 37°15′ latitude and E 45°05′, 45°30′ longitude which is composed of Permian dolomitic limestone, limestone, and post-Jurassic granite with a very low primary porosity/permeability character. In order to delineate groundwater potential zones in this area, the study focused on identifying secondary porosity/permeability indicators such as lineaments, vegetation cover, lithology, drainage pattern, drainage density, etc. In this regard, a remote sensing and geographic information system-based methodology was selected. Landsat ETM, IRS (pan), SPOT data, digital elevation model, and digital image processing techniques such as filtering, false color composite, principal component analysis, band rationing and classification have been applied to reach the purposes. Information layers extracted for analysis and interpretation stage were then integrated with other data and modeled through the use of existing geographic information system (GIS) software and their related analytical functions. Finally, based on determined ground water favorability index for different sub zones, layers, weighting, and overlapping, a ground water potential index (GWPI) was defined which respectively was utilized to groundwater potential zoning and preparation of GWPI map of the region. Within the six different sub zones defined, two sub zones labeled with high and very good potential areas were highly recommended for further development and exploration purposes. Geophysical investigations in target areas confirm the labeled subzones. Based on the obtained results of the study, it can be concluded that remote sensing data are very useful tool to extract information of groundwater exploration. Also, application of geographic information systems to find target areas for groundwater exploration are effective to save time and cost.  相似文献