Curie point depth beneath the Barramiya–Red Sea coast area estimated from aeromagnetic spectral analysis     

Sami Hamed Abd El Nabi 《Arabian Journal of Geosciences》2012,5(6):1209-1221

The geothermal structure beneath of the Barramiya?CRed Sea coast area of the Central Eastern Desert of Egypt has been determined using Curie point depth (CPD), which is temperature-dependent. The CPD and the surface heat flow (q) maps of such area are estimated by analyzing aeromagnetic data. Such data are low-pass-filtered and analyzed to estimate the magnetic bottom using the centroid method. The heat flow map reflects the geothermic nature of the region. However, it is suggested that the shallow Curie point temperature depth pattern depends on the tectonic regime and morphology, which continues eastwards through the Red Sea. Particularly, the coastal regions are characterized by high heat flow (83.6?mW/m²) and shallow Curie depth (22.5?km), whereas the western portion of the studied area has a lower heat flow (<50?mW/m²) and deeper Curie depth (~40?km). In addition to its bordering to the Red Sea margin, such high heat flow anomaly is associated with the increased earthquake swarms activity in the Abu Dabbab area. El-Hady (1993) attributed the swarm activity to the geothermal evolution. Also, the heat flow pattern is correlatable by the numerous results of shallow borehole temperature measurements as reported by Morgan and Swanberg (1979). A significant low heat flow extending in the northeast?Csouthwest direction, which is associated with NE?CSW large areal extent negative Bouguer gravity anomaly and NE/SW-trending belt of the deep CPD region, seems to be directly related to the surface outcrops of Precambrian older granitoids of the mountainous range of that trend.  相似文献   

U–Pb ID-TIMS dating of igneous and metaigneous rocks from the El-Sibai area: time constraints on the tectonic evolution of the Central Eastern Desert,Egypt     

Lars Eivind Augland  Arild Andresen  Gamal Yehia Boghdady 《International Journal of Earth Sciences》2012,101(1):25-37

This paper presents new ID-TIMS U–Pb zircon and titanite ages from the El-Sibai gneiss complex in the Eastern Desert of Egypt. The zircon data support previous studies, indicating that the protoliths of the gneissic (oldest) units in the area were emplaced during the East African orogeny, and do not represent an older pre-Neoproterozoic, reworked cratonic basement. The crystallization ages of three compositionally distinct orthogneiss protoliths are c. 685, 682 and 679 Ma, respectively. A U–Pb titanite age from one orthogneiss overlaps with the protolith age, indicating that the gneisses did not undergo post-magmatic high-temperature metamorphism. The gneissic textures of the rocks are therefore interpreted to reflect syn-emplacement deformation. This, and evidence for static amphibolite facies metamorphism in country-rock metavolcanics, lead us to conclude that the gneisses of El-Sibai do not represent an exhumed middle crustal gneiss dome, but are part of the island arc affined allochthon into which they were emplaced synchronously with NW-ward nappe translation. We also report ages from rocks cross-cutting the gneisses and the surrounding island arc affined assemblages that yield the hitherto youngest robust pre-Cretaceous intrusive ages in the Eastern Desert. The dated rocks are an anorthosite and a cross-cutting syenogranite giving ages of c. 541 and 540 Ma, respectively. We consider this late magmatic pulse to be anorogenic, most likely reflecting a separate extensional event involving asthenospheric upwelling and decompression melting of the mantle.  相似文献   

Killing vectors of Schwarzschild space-times in teleparallel equivalent of general relativity     

Gamal G. L. Nashed 《Astrophysics and Space Science》2011,333(1):317-325

We derive three different solutions in the framework of the teleparallel equivalent of general relativity (TEGR). We apply the energy-momentum tensor to calculate energy, irreducible mass, spatial momentum and angular-momentum associated with these solutions. We obtain anomalous physical results therefore, we calculate the Killing vectors using the definition of the Lie derivative.  相似文献   

Groundwater vulnerability and risk mapping of the Hajeb-jelma aquifer (Central Tunisia) using a GIS-based DRASTIC model   总被引：7，自引：2，他引：5  

Salwa Saidi  Salem Bouri  Hamed Ben Dhia 《Environmental Earth Sciences》2010,59(7):1579-1588

The aim of this study is to elaborate a synthetic document for the assessment of groundwater vulnerability to pollution in the Hajeb-Jelma aquifer. The specific object is to incorporate the Geographical Information System (GIS) to generate groundwater vulnerability and risk maps with DRASTIC model. Indeed, GIS could help to make the results of a complicated model more clear through visual representation, providing an applicable tool for decision makers. The vulnerability map of Hajeb-Jelma watershed shows three classes: moderate, high and very high depending on the intrinsic properties. The risk map shows a very high risk dependant on hydrogeological characteristics, land use and human impacts in major part of the Hajeb-Jelma region. These maps could serve as a scientific basis for sustainable land use planning and groundwater management in the Hajeb-Jelma region.  相似文献   

Stationary axisymmetric solutions and their energy contents in?teleparallel equivalent of Einstein theory     

Gamal G. L. Nashed 《Astrophysics and Space Science》2010,330(1):173-181

We apply the energy-momentum tensor which is coordinate independent to calculate the energy content of the axisymmetric solutions. Our results are compared with what have been obtained before within the framework of Einstein general relativity and M?ller’s tetrad theory of gravitation.  相似文献   

Erratum to: Properties of geothermal resources in Kebilli region, Southwestern Tunisia     

Fatma Ben Brahim  Jalila Makni  Salem Bouri  Hamed Ben Dhia 《Environmental Earth Sciences》2013,69(6):2125-2125

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The hydrogeochemical characterization of groundwater in Gafsa-Sidi Boubaker region (Southwestern Tunisia)     

Younes Hamed 《Arabian Journal of Geosciences》2013,6(3):697-710

Gafsa region is one of the most productive artesian basins in Southern Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. Proper understanding of the geochemical evolution of groundwater is important for sustainable development of water resources in this region. A hydrogeochemical survey was conducted on the Plio-Quaternary shallow and on the Complex Terminal aquifers system using major (Ca, Mg, Na, SO₄, Cl, NO₃ and HCO₃) and minor (Sr) elements, in order to evaluate the groundwater chemistry patterns and the main mineralization processes occurring in this system. Hydrochemical and isotopic data were used in conjunction with hydrogeological characteristics to investigate the groundwater composition in these aquifers. It has been demonstrated that groundwaters acquire their mineralization principally by water–rock interaction, i.e. dissolution of evaporites (halite/gypsum, pyrite, etc.) and return flow of irrigation waters, and by anthropogenic activities due to the use of nitrogen (N) fertilizers–pesticides in agriculture. The isotopic study of “stable isotopes, radiocarbon and tritium” (Yermani 2002) shows that a paleoclimatic recharge is corroborated by the relatively low carbon-14 activities (5–25.3%) of the referred groundwater group samples, which were interpreted as recharge occurring during the late Pleistocene and the early Holocene periods. The water feedings of these aquifers are mainly provided by infiltration of precipitations, infiltration of irrigation water, lateral feeding from Cretaceous relieves from the South and the North and along recent and fossil drainage networks that constitute major freshwater sources in groundwater tables (Hamed et al., J Environ Protect 1:466–474, 2010a).  相似文献   

Detailed surface photometry of some galaxies integrated properties,II     

A. I. Gamal el Din  I. A. Issa  A. M. I. Osman  F. Y. Kamal 《Astrophysics and Space Science》1992,190(1):89-117

Results about the standard photometric parameters of four galaxies are given. The equivalent and the integrated parameters defined according to de Vaucouleurs are listed. Effective values of the abovementioned ingredients, the reduced luminosity profiles and the dimensions defined by the quartiles are also given.  相似文献