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11.
Mahmoud Elsaid Hatem Aboelkhair Ahmed Dardier Elsayed Hermas 《Arabian Journal of Geosciences》2014,7(11):4615-4628
In this paper, an attempt was tried to study the relation between radiogenic heat production rate (RHPR) that derived from gamma-ray spectrometric data and the kinetic surface temperature KST, which was calculated from the thermal emission and reflection radiometer-thermal infrared (ASTER-TIR) imagery applied on Elmissikat-Eleridiya district. This area is considered one of the most important uranium localities in the Central Eastern Desert of Egypt. The gamma-ray spectrometric data including both airborne data and in situ measurements concurrent with the collection of 20 rock samples were used to determine the rock density. The ground gamma-ray spectrometry has been conducted using GS-256 spectrometer at the same locations of rock samples. The gamma-ray spectrometric data (airborne and ground) beside rock density data were used for calculating RHPR. Alongside, pairs of daytime and nighttime ASTER-TIR images were collected and surface kinetic temperature for both day (daytime kinetic surface temperature (DKST)) and night (nighttime kinetic surface temperature (NKST)) were derived by using reference channel emissivity technique. The study showed a relative higher RHPR within syenogranite (4.2 up to 6 μW/m3) than other rock units. Besides, the KST of syenogranite ranged from 33 to 48 °C in daytime and between 7 and 17 °C at night. Comparing all results, no clear relation between RHPR and KST is evident. This is due to the very weak RHPR that is not sufficient to affect the surface heat temperature, which can be remotely sensed by ASTER satellite TIR data. This factor in addition to other factors such as: structural elements, topography, geographic locations, shading and scattering, rock moisture and density, can strongly affect the surface temperature. In conclusion, these results could be improved in areas of very high radioelement concentrations, especially 235U and through the use of the enhanced spatial resolution of future satellite TIR imaging instruments. 相似文献
12.
Stepwise hydrochemical and isotope-based methodology was adopted to identify mineralization processes, assess the impact of resources overexploitation and flood irrigation, and conceptualize groundwater hydrodynamics in the Djérid aquifer system, Tunisia. The study demonstrates that the main processes controlling groundwater geochemistry are dissolution of evaporates and phosphate-bearing rocks, cation exchange, mixing between high and low TDS end-members, and irrigation return flow. Interpretation of isotope data demonstrates that the deep aquifer was mostly recharged by late Pleistocene palaeowater, while the shallow aquifer is entirely recharged by return flow. The intermediate aquifer groundwater is actually a mixing of early to middle Holocene palaeowater, late Pleistocene deep aquifer palaeowater and return flow waters. The established conceptual model shows that deep and shallow groundwater leakages into the intermediate aquifer are enhanced by the presence of deep faults, the high hydraulic head of the deep aquifer, the overexploitation of the intermediate aquifer, and the long-term flood irrigation. 相似文献
13.
Hatem Baccour 《水文科学杂志》2013,58(4):818-829
Résumé Nous étudions sur le territoire Tunisien, transition entre les climats sub-humide Méditerranéen et aride Saharien, l'organisation spatiale de l'évapotranspiration de référence décadaire interannuelle (1986–2003) et des variables climatiques utilisées pour son estimation: température de l'air, humidité relative de l'air, vitesse du vent et durée d'ensoleillement. L'étude est basée sur la modélisation du variogramme et la détermination de ses paramètres (pépite, pente ou palier et portée). Nous considérons également des indicateurs sur le comportement à l'origine du variogramme et sur la variation de la structure spatiale des variables étudiées. L'étude montre que les modèles des variogrammes changent d'une variable à une autre et d'une période de l'année à une autre. Cependant, ils sont de type linéaire dans la plupart des cas. Le variogramme de l'évapotranspiration de référence est sans pépite, quelle que soit la période de l'année. Pour les autres variables, notamment la température maximale de l'air, l'humidité relative de l'air et la durée d'ensoleillement, la pépite est plus importante pendant la période chaude de l'année. Le variogramme de la vitesse du vent est sphérique à grande portée sur toute l'année, et la structure de l'ensoleillement est pépitique pendant l'été et linéaire le reste de l'année. L'évapotranspiration de référence présente un gradient structural semblable à celui de l'humidité relative durant toute l'année, mais différent de ceux des autres variables climatiques. Editeur Z.W. Kundzewicz; Editeur associé G. Mahé Citation Baccour, H., Slimani, M. et Cudennec, C., 2012. Structures spatiales de l'évapotranspiration de référence et des variables climatiques corrélées en Tunisie. Hydrological Sciences Journal, 57 (4), 818–829. 相似文献
14.
Hatem Odah Ahmed Ismail Ibrahim Elhemaly Neil Anderson Abbas M. Abbas Fathy Shaaban 《Arabian Journal of Geosciences》2013,6(3):865-871
The Hatshepsut Temple at Luxor, southern Egypt was built as a garden for Amun, and the first court indeed had exotic trees and vegetations. The pathway to the temple was along a sphinx-lined causeway linking the valley to pylons, which are missing now. As an effort to outline remains of the vanished garden and missing pylons and any other possible archaeological structures at this first court site, an extensive integrated magnetic/ground-penetrating radar (GPR) geophysical survey was conducted. The magnetic survey covered the entire area of the first court (100?×?60 m), while the GPR survey covered only an area of 50?×?50 m. The acquired GPR data were processed and presented as 2-D depth sections providing a reasonable vertical/horizontal resolution for the upper 6 m of the investigated site. The acquired magnetic data was processed and presented as 2-D image. The integrated interpretation of the acquired GPR and magnetic data revealed some archaeological features including a rectangular depression which is presumably an ancient man-made pond in the garden of the temple, a rectangular feature that may be a foundation of the missing pylon of the temple, and a suite of aligned anomalies that could be the remnants of sphinx. Such findings reflect the archaeological potentiality of the surveyed site and outline the extension of the temple. Meanwhile, these results necessitate further geophysical investigation or archaeological excavation to be confirmed. 相似文献
15.
The shallow subsurface structures of the offshore Nile Delta particularly in the southeastern Mediterranean were dealt through the interpretation of 40 two-dimensional seismic reflection lines. The interpretations of seismic reflection data indicated that the principle sedimentary processes affecting the study area include three main structural groups according to their origin and development. The first group of structures comprises of gravity-driven structures, which include slides, slumps, turbidities, and debris flow. Slides are present in three different forms on seismic sections: slide sheets, slides with scar, and wedges of slide materials. Slumps have many geometrical shapes: lenses, spoon-shaped slumps, and slumped blocks bound by growth faults. Debris flows are present as transparent unit (due to the dispersion of seismic waves at debris boundaries), whereas turbidities appear on the seismic profiles, which are formed of closely spaced parallel thin reflectors analogous to their thin stratified bedded layers. The second group of structures is syn-depositional structures, which include growth faults, and tilted and rotated fault blocks. Growth faults are listric in shape and usually dip seaward; displacements along the fault plane increase with depth. Some of these faults are incipient, and some are complicated and intersected by secondary antithetic faults. Most of the growth faults soles out basin wards and in the evaporites layer. Fault blocks are formed due to the Messinian evaporite movement vertically and horizontally due to its mobility as a consequence to the pressure resulted from the overloading of Pliocene sediment. The third group of structures comprises evaporite flow structures such as diapiric structures and graben collapse structures. The surface of the Messinian evaporites was folded during its flow as a consequence to the lateral compression acted on the mobile strata of the Messinian evaporites to form diapiric triangular structures and creates a stress zone faulting and fractures system. These conditions led to the formation of collapse structures or graben collapse structures. 相似文献
16.
Sultan Awad Sultan Hatem M. Mekhemer Fernando M. Santos 《Arabian Journal of Geosciences》2009,2(3):199-211
Different geophysical tools such as geoelectric, gravity, and magnetic have been applied to detect groundwater potentiality
and structural elements, which controlled a geometry of the groundwater aquifers in the study area. Nineteen vertical electrical
soundings measured using ABEM SAS 4000 equipment through Schlumberger configuration of AB/2 ranged from 1.5 to 1,000 m; the
quantitative interpretation was carried out using manual and analytical techniques. The results of quantitative interpretation
used to construct six geoelectrical cross-sections indicate that the subsurface sequence of the study area consists of seven
geoelectrical units. These units are Quaternary sand sheet and sand dunes, Quaternary aquifer, marly limestone, clay, sandy
clay, clay with sandstone intercalation, and deep Nubian sandstone aquifer. The isopach map of the Quaternary aquifer exhibits
thickness of the Quaternary aquifer that increased at the northern and southern part (50 m) and decreased at the eastern and
western part (5 m), and the depth of the aquifer increased at the northern part (40 m) and decreased at the central part to
6 m. The isoresistivity map of the aquifer shows a high resistivity at the northern part but the southern part reveals low
resistivity according to the lithology. The water salinity increases in the direction of groundwater flow from 500 to 10,500 mg/l.
The low water salinity is due to direct recharge from El-Sheikh Zayed Canal, which supplied fresh water to this area. Sixty-five
gravity stations were measured using Auto-Grav gravity meter; different gravity corrections were applied on raw data. The
corrected gravity values were plotted to represent a Bouguer anomaly map; the residual gravity anomaly map was used for delineation
of the fault elements. The area was dissected by different fault elements of trends NW–SE, NE–SW, and E–W. In addition, 65
ground magnetic stations were measured at the same sites of gravity stations. The results of magnetic interpretation indicate
that the depth of the basement is shallow at the western and southern parts of the area (4,500 m), but the central part exhibits
greater depth of 7,900 m.
الملخص العربي طرق جيوفيزيقية مختلفة مثل الكهربية الأرضية, التناقلية الأرضية والمغناطيسية الأرضية تم تطبيقها لتحديد إمكانية تواجد المياه الجوفية والتراكيب الجيولوجية التي تتحكم في إبعاد وهندسة الخزان الجوفي في منطقة الدراسة. تسعة عشر جسة كهربية عمودية تم قياسها باستخدام جهاز من شركة (ِ ABEM) ساس 4000 من خلال تشكيل شلمبرجير بمسافة بين القطبين أب /2 تبدأ من 1.5 متر حتى 1000 متر, التفسير الكمي تم علي البيانات باستخدام التفسير اليدوي والتحليلي. نتائج التفسير الكمي تم استخدامها لتشييد ست قطاعات جيوكهربية والتي أوضحت أن التتابع التحت سطحي لمنطقة الدراسة يتكون من سبعة وحدات جيوكهربية. هذه الوحدات هي صفائح من الرمال والكثبان الرملية للعصر الرباعي, الخزان الجوفي الرباعي, حجر جيري مارلي, طفلة, طفله رمليه, طفله متداخلة مع الرمل والخزان الجوفي النوبي. خريطة السمك للخزان الجوفي الرباعي تظهر أن سمك الخزان الجوفي الرباعي يزيد عند شمال وجنوب منطقة الدراسة (50 متر) ويقل عند الجزء الشرقي والغربي (5 متر). وعمق هذا الخزان الجوفي الرباعي يزيد عند الجزء الشمالي (40 متر) وينقص عمق الخزان الرباعي عمد وسط المنطقة (6 متر). خريطة المقاومة الحقيقية للخزان الجوفي الرباعي تبين أن المقاومة تزيد عند الجزء الشمالي وتقل المقاومة عند الجزء الجنوبي من منطقة الدراسة بناءا علي التكوين الصخري للطبقات. ملوحة المياه الجوفية تزيد في اتجاه سريان المياه من 500 مليجرام/لتر إلي 10500 مليجرام/لتر. نقص الملوحة المياه ناتج عن التسرب المباشر من قناة الشيخ زايد والتي تعتبر مصدر المياه العزبة في منطقة الدراسة. خمس وستون محطة تثاقيلية أرضية تم قياسها باستخدام اوتو-جرافميتر, العديد من تصحيحات الجاذبية الأرضية نم تطبيقها علي البيانات الأصلية. قراءات الجاذبية الأرضية المصححة تم رسمها علي خريطة لتمثل شاذات البوجير وتم استخدام خريطة الشاذات المحلية لتجديد التراكيب الجيولوجية (الفوالق). حيت أوضحت الدراسة أن المنطقة تأثرت بعده فوالق باتجاهات مختلفة مثل شمال غرب- جنوب شرق, شمال شرق-جنوب غرب وشرق-غرب. نتيجة تفسير بيانات المغناطيسية الأرضية أظهرت أن عمق ضجور القاعدة تكون ضحلة عند الجزء الغربي والجنوبي (4500 متر) وتكون ضجور القاعدة عميقة (7900 متر) عند الجزء الأوسط من منطقة الدراسة.相似文献
17.
Ahmed E. Khalil Hatem M. El-Desoky Taher M. Shahin Wael Abdelwahab 《Arabian Journal of Geosciences》2018,11(4):74
Wadi Hammuda is dominated by a variety of low grade regionally metamorphosed volcaniclastic metasediments pertaining to two different geotectonic settings and intruded by arc and late collision granitic rocks. Thus, the volcaniclastic metasediments which form extensive outcrops are considered as a member of island arc assemblages. This paper deals with the petrography, geochemistry, and tectonic setting of the island arc volcaniclastic metasediment rock units. The volcaniclastic metasediments consist of interbedded metagreywackes, metasiltstones, metamudstones, and schists as well as metapyroclastics. They are well foliated, crenulated and tightly folded, metamorphosed, and intruded by granitic rocks. Geochemical data support the petrographic classification and reveal that these volcaniclastic metasediments are generally low-K, essentially tholeiitic in character, with the exception of some metasediments and metapyroclastics which exhibits calc-alkaline and tholeiitic affinities and represent the first stage of island arc volcanism. The overthrusted oceanic lithosphere blocks with fragments of the fore arc and/or back-arc marginal basins volcaniclastic metasediments were incorporated among the island arc volcanics which supported by tectonically relationship between the different rock units in the study area. Contemporaneous with this deformation event, Wadi Hammuda was subjected to low grade regional metamorphism and the rocks document an early phase of shearing and/or foliation. Occasionally minor folds were developed particularly in the metasediments and schists. The subsequent emplacement of the syn-tectonic granites (tonalites and granodiorites) resulted in minor local thrusts. During the regional thrusting event which preceded the emplacement of the late-tectonic granites (alkali feldspar granites) and affected the whole region, low grade successions cover the study area similar to the Meatiq volcaniclastic metasediments. 相似文献
18.
Mohamed A. El-Sadek Ahmed A. Ammar Mohamed A. Omran Hatem M. Abu Elkheer 《Arabian Journal of Geosciences》2011,4(7-8):1151-1161
Two significant airborne gamma ray spectrometic (AGRS) statistical parameters, i.e., the arithmetic mean and the standard deviation, were computed for all lithologic units and formations of the Bahariya Oases area, Northern Western Desert, Egypt. The results ascertain that the maximum AGRS values are associated with sabkha sediments, Bahariya Formation, basalt flows and sand dunes. The intermediate values are correlated with El-Heiz, El-Hefhuf, Qazzun and Naqb formations. The minimum values are connected with Khoman Chalk and El-Hamra formations. The AGRS records were found to vary from one type of rock to another and to some extent between units of the same rock type too. On the aerial total-count (TC) radiometric maps, the records change from 6.2 to 69.36 μR/h. On the potassium map, the values range from 0.05% to 4.35%. On the equivalent uranium (eU) and equivalent thorium (eTh) maps, the records oscillate from 0.12 to 7.4 ppm and from 0.28 to 8.4 ppm, respectively. Concerning the Bahariya Oases area, the calculated arithmetic mean natural dose rate values originating from the terrestrial gamma radiation were found to range from 0.14 to 0.26 mSv/year and where the maximum value attains 0.62 mSv/year. These values remain on the safe side and within the maximum permissible safe radiation dose without harm to individuals, with continuous external irradiation of the whole body. 相似文献
19.
Hydrocarbons in surface sediments from the Sfax coastal zone, (Tunisia) Mediterranean Sea 总被引：1，自引：0，他引：1
Zaghden H Kallel M Louati A Elleuch B Oudot J Saliot A 《Marine pollution bulletin》2005,50(11):1287-1294
The Semi-enclosed Mediterranean Sea records various signals of high anthropic pressures from surrounding countries and the industrialized European countries. This is particularly true for oil pollution. Although accounting for 1% of the world's ocean surface, it receives about 25% of the petroleum inputs to the ocean. To achieve a global budget we need to collect information from different parts of the Mediterranean. Particularly, we focus in this paper on the Southern Mediterranean, where data are presently very scarce. In this context, the University of Sfax has undertaken an estimation of hydrocarbon pollution along the coasts of Sfax and Gabès Gulf. Non-aromatic hydrocarbons were analysed in 8 surface sediments by FT/IR and GC/MS. Non-aromatic hydrocarbon concentrations vary in the range 310-1406 microg g(-1) sediments dry weight, which is high, compared to other Mediterranean sites. GC/MS data indicate a large group of unresolved compounds suggesting a petroleum contamination, confirmed by the identification of hopanes with predominant C29 and C30alpha,beta compounds and steranes with predominance of C27 over C28) and C29 compounds. 相似文献
20.
A ground‐based gamma‐ray survey has been performed in the area close to El‐Ramlah village, southwestern Sinai, Egypt, using a GS‐512 spectrometer. The main objective of this survey was to delineate radioactive anomalies within the surface of the study area and to identify the environmental effects of natural radioelements on the new inhabitants, Bedouins, who live in the recently built village in this region of the Sinai Peninsula. The results show that the maximum radioactivity of the total count component (T.C.) was about 15.7Ur at the northern part of the study area. The average radioelements concentration were 0.4% for potassium, 1.6 ppm for equivalent uranium and 4.5 ppm for equivalent thorium. To identify and map the environmental effects of the concentration of these radioelements on El‐Ramlah village, measurements of potassium (K%), equivalent uranium (eU) and equivalent thorium (eTh) were converted into an equivalent dose rate. The results illustrate that, the levels of effective dose rate of the natural radioactivity of the area of study remains in the safe range without any harm to living organisms, and it stays within the maximum permissible radiation dose rate (1.0 mSv y?1) recommended by the International Commission of Radiological Protection. 相似文献