Basin analysis study of block 10 in the Say'un-Masilah Basin, Yemen, using a 1D backstripping method     

Adel Mohammad Al-Matary  Hilal M. Ahmed 《Arabian Journal of Geosciences》2012,5(3):529-543

Geohistory analysis was carried out on block 10 in the Say??un-Masilah Basin. The present study is based on the analysis of the well logs of six exploration wells. In the Middle Jurassic to the Middle Eocene, Say??un-Masilah Basin exhibited a complex subsidence history over a period of about 155?Ma. Backstripped subsidence curves are constructed by removing the effects of decompaction to the water column and sediment loads. In the Middle Jurassic, slow subsidence was driven under the effect of sediment load as Kuhlan and Shuqra Formations were deposited as pre-rift deposits. The average total subsidence value of the basement during the deposition of Shuqra Formation was 276?m. The highest subsidence rates during this time are observed northeast of the study area. Rapid subsidence initiated in the Upper Jurassic driven by mechanical extension of the rift, resulting in the deposition of Madbi and Safer Formations, or the so-called Syn-rift deposits. The average tectonic subsidence value of the basements during the deposition of Madbi Formation was 368?m. The highest subsidence rates during this time are observed southwest of the study area. Mechanical extension ceased at about 145?Ma, being replaced by a phase of post-rift subsidence, resulting in more widespread uniform sedimentation, with reduced tectonic subsidence rates forming post-rift deposits represented by Nayfa Formation, Sa??ar Formation, Biyad Formation, and Mahra Group. The total subsidence value of the basement during the deposition of the post-rift sediments increases gradually due to the increase of the sediment load as the rate of deposition was high especially northeast of the area.  相似文献   

Dokhan volcanics of Gabal Monqul area,North Eastern Desert,Egypt: geochemistry and petrogenesis     

Adel A. A. Abdel Wahed  Khaled G. Ali  Magdy M. A. Khalil  Ahmed E. Abdel Gawad 《Arabian Journal of Geosciences》2012,5(1):29-44

The Dokhan volcanics are represented by a thick stratified lava flows succession of basalt, andesite, imperial porphyry, dacite, rhyodacite, rhyolite, ignimbrites, and tuffs. These lavas are interbanded with their pyroclastics in some places including banded ash flow tuffs, lithic tuffs, crystal lapilli tuffs, and agglomerates. They are typical calc–alkaline and developed within volcanic arc environment. All rocks show moderate enrichment of most large ion lithophile elements relative to high field strength elements (HFSE). The incompatible trace elements increase from basalt through andesite to rhyolite. The felsic volcanics are characterized by moderate total rare earth elements (REE) contents (162 to 392 ppm), less fractionated patterns {(Ce/Yb)_N = (1.24 to 10.93)}, and large negative Eu anomaly {(Eu/Eu*) = (0.15 to 0.92)}. The mafic volcanics have the lowest REE contents (61 to 192 ppm) and are relatively steep {(Ce/Yb)_N = (3.2 to 8.5)}, with no negative Eu anomalies {(Eu/Eu*) = (0.88 to 1)}. The rhyolite displays larger negative Eu anomaly (Eu/Eu* = 0.28) than those of other varieties, indicating that the plagioclase was an early major fractionating phase. The mineralogical and chemical variations within volcanics are consistent with their evolution by fractional crystallization of plagioclase and clinopyroxene.  相似文献   

Efficient algorithms for the earth's gravitational potential and its partial derivatives for satellite prediction     

Mohamed Adel Sharaf  Mervat El-Sayed Awad  Mona A. Banaja 《Earth, Moon, and Planets》1989,47(2):171-192

In this paper, economical recursion formulae for the Earth's gravitational potential and its partial derivatives with respect to the Cartesian coordinates, and time will be established for any number and any type of the harmonic coefficients. General computational algorithms for their implementations on digital computers are also given.Now at the Department of Astronomy, King Abdul-Aziz Univ., Jeddah, Saudi Arabia.Now at the Department of Mathematics, Girls College of Education, Jeddah, Saudi Arabia.  相似文献   

Water quality and phytoplankton communities in Lake Qarun (Egypt)     

Adel A. Fathi  Roger J. Flower 《Aquatic Sciences - Research Across Boundaries》2005,67(3):350-362

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General integral operator for radiative transfer problems     

Mohamed Adel Sharaf  Zainab Khan  Faizah Al-Bassam 《Astrophysics and Space Science》1987,129(2):303-319

General integral operator for radiative transfer problems is considered and will be denoted asK ^k {g(t)}.General theorems for theK-operator valid to any smooth functiong(t) will be established. The effect of the operator to the functions oftenly occur in transfer problems will also be established analytically and computationally.  相似文献   

Use of Tunisian raw clay to remove dye from aqueous solution     

Chaâri Islem  Jridi Kamel  Fakhfakh Emna  Jamoussi Fakher  Mnif Adel 《Arabian Journal of Geosciences》2016,9(10):564

This paper presents the first attempt to investigate the potential of Tunisian palygorskite-rich clay (Pal-clay) on the effectiveness of a textile dye “Direct orange 34” (DO34) removal. Important parameters which affect adsorption, such as initial solution pH, contact time, adsorbent mass, initial dye concentration, and temperature, were investigated. The raw Pal-clay was characterized using X-ray diffractometer (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), cation exchange capacity (CEC), specific surface area (SSA) analysis, and point of zero charge (PZC) determination. The results showed that the Pal-clay has a high selectivity for DO34 and had maximum removal efficiency reaching up to about 91 %. The highest adsorption capacity was obtained at 25 °C and pH of 2. The dye uptake process fitted well to the pseudo-second-order kinetic expression and was best described by the Langmuir and Freundlich isotherms. Intra-particle diffusion studies showed that the adsorption mechanism was not exclusively controlled by the diffusion step and was more likely to be governed by external mass transfer. Thermodynamic parameters such as change in free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also calculated. The parameters revealed that the adsorption of dye by the raw clay is spontaneous and exothermic. The results indicate that the Pal-clay has a moderate adsorption capacity towards anionic dye.  相似文献   

Vulnerability of flash flooding in Riyadh,Saudi Arabia     

Muhammad Tauhidur Rahman  Adel S. Aldosary  Kh Md Nahiduzzaman  Imran Reza 《Natural Hazards》2016,84(3):1807-1830

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Geochemical Characterization Given by Rock-Eval Parameters and N-alkanes Distribution on Ypresian Organic Matter at Jebel Chaker, Tunisia     

Adel Arfaoui  Mabrouk Montacer 《Resource Geology》2007,57(1):37-46

Sedimentary rock samples from Jebel Chaker in the eastern part of the Ypresian basin in central‐northern Tunisia were analyzed using various geochemical methods in order to decipher their organic signature. Examination of the distribution of total organic carbon (1.04–1.82%) suggests that the petroleum potential of Ypresian facies is not ignored in such area. The Ypresian episode permitted the accumulation of organic matter, which is typically marine plankton as indicated by the unimodal distribution of N‐alkane at nC₁₈ and by the predominance of the aliphatic hydrocarbons compared to the aromatics. It is concluded that the Ypresian organic matter is relatively immature, as indicated by the high content of polar compounds (3–67%) in bitumen. This conclusion is supported by the relative low T_max values (433–438°C), suggesting that the organic matter is located towards the end of diagenesis and beginning of catagenesis. These new results testify to the establishment of suboxic conditions that led to the accumulation and preservation of good quantities of organic matter in central‐northern Tunisia during the Ypresian. Due to their geochemical characteristics, the Chaker facies represent new potential source rocks in central‐northern Tunisia.  相似文献   

Seismic microzonation of Marsa Alam, Egypt using inversion HVSR of microtremor observations   总被引：1，自引：0，他引：1  

Sherif El-Hady  Elsayed Abdel-Azeem Fergany  Adel Othman  Gad ElKareem Abdrabou Mohamed 《Journal of Seismology》2012,16(1):55-66

An attempt was made to estimate seismic microzonation in Marsa Alam city, Egypt based on the analysis of seismic microtremor observations. Observations were carried out at 140 sites in the study region. Analysis and processing of microtremor were divided into two steps; the first one is to measure the horizontal-to-vertical spectral ratios (HVSR) for each site and picked predominant frequency and its amplitude for each site. The second step is to measure the average shear wave velocity in the upper 30 m (Vs30) of subsoil using inversion of HVSR technique. The results show well matching of theoretical HVSR and observed HVSR for body waves in all sites. The Vs30 parameter was used to classify subsoil into classes of soil properties converted to the slandered European soil code (Eurocode-8 (2002)) as follows; Vs < 180(class D), 180 ≤ Vs < 360 (class C), 360 ≤ Vs < 800 (class B) and Vs ≥ 800 m/s (class A). Our study exhibits that most of Marsa Alam city were covered by B and C classes with small portions of class D close to the shoreline and class A at the northeastern part of the region. The developed classification soil map of the study area was correlated with the distribution of the predominant frequency in view of the surface geology and given a good matching. The results of this study will be useful for planning the Marsa Alam region to be the future tourist dream for Egypt. The method used in assessment of seismic microzonation in Marsa Alam city could be the fast and inexpensive technique to measure the Vs30 based on the HVSR of microtremor and would be applied in many other areas in Egypt.  相似文献   

Delineation of Near-Surface Structure in the Southern Part of 15th of May City, Cairo, Egypt Using Geological, Geophysical and Geotechnical Techniques     

Adel M. E. Mohamed  Sultan A. Sultan Araffa  Nagi I. Mahmoud 《Pure and Applied Geophysics》2012,169(9):1641-1654

The integration of geological, geophysical, and geotechnical interpretation at the southern part of 15th of May City, have been used to evaluate the subsurface stratigraphy, especially the clay layer which may cause serious danger to construction. Those techniques have been used to delineate the subsurface structures as normal faults, which play a critical role on the stability of buildings. Geological setting of the area has been evaluated through the construction of a geological map from different geological sections and samples obtained from more than 30 observation points. Geophysical tools such as vertical electrical soundings (12 VESs), 2-D dipole–dipole array (7 sections), P-wave shallow seismic refraction (31 profiles) and multiple channel analysis of surface waves (31 MASW profiles) have been carried out to image the subsurface situation. Geotechnical evaluation using 26 boreholes, samples, laboratory tests and geotechnical parameters has been done at the area of interest. The geological setting demonstrates that the city had been constructed on the second and third members of Qurn Formation (Upper Eocene) composed of argillaceous limestone, marl and shale. Two normal faults are passing through the area were observed. The resistivity (VES and dipole–dipole) and seismic (P-waves and MASW) results reflect the presence of the two normal faults cross the study area, affecting the obtained section of marl, clayey marl and limestone layers. The geotechnical information indicate the presence of the normal faults and the existence of clay layer with swelling ability reaching 140%, which may cause cracks in the upper layers and/or subsidence.  相似文献