Geochemistry and mineral chemistry of lode gold mineralisation, SE Egypt: implications for ore genesis and exploration     

Basem A. Zoheir  Mohamed G. Abdel-Fattah  Sameh M. ElAlfy 《Arabian Journal of Geosciences》2013,6(12):4635-4646

Orogenic, lode gold mineralisation in the South Eastern Desert of Egypt is related to quartz veins spatially and temporally associated with conjugate NW- and NE-trending brittle–ductile shear zones. These structures are assumed to be linked to a regional transpression deformation which occurred late in the tectonic evolution of the area. In the Betam deposit, gold is confined to quartz(±carbonate) veins cutting through tectonised metagabbro and metasedimentary rocks in the vicinity of small granite intrusions. The ore bodies contain ubiquitous pyrite and arsenopyrite, in addition to minor disseminated chalcopyrite, pyrrhotite, galena, tetrahedrite and rare gold/electrum. New ore microscopy and electron microprobe studies indicate that most free-milling Au is intimately associated with the late-paragenetic galena–tetrahedrite–chalcopyrite assemblage. An early Fe–As sulphide assemblage, however, shows minor traces of refractory gold. New mineralogical and geochemical data are used to better constrain on possible element dispersions for exploration uses. This study indicates that parameters that most consistently define primary dispersion of gold in the mine area include pervasive silicification, sericite and carbonate alteration. The trace element data of gold lodes reflect a systematic dispersion of gold and certain base metals. Low-cost, extensive exploration programs may use elevated concentrations of Ag, Sb, Cu and Pb as tracers for Au ore zones in the Betam mine area and surroundings.  相似文献   

Abu Roash G dolomite reservoir characterization using seismic inversion technique, Horus field, Western Desert, Egypt     

Omar Mohamed Hassan Al Mahdy  Mohamed Salah Sedek 《Arabian Journal of Geosciences》2013,6(6):1769-1797

The main objective of this paper was the characterization of the reservoir (Abu Roash G dolomite) in terms of acoustic impedance from surface seismic data complemented by available well logs. To reach our target, a two-step procedure was followed: first, identification of the reservoir signatures using synthetic seismogram using Strata program in Hampson–Russell software and second, applying inversion technique to the post-stack seismic data using Strata program in Hampson–Russell software to obtain acoustic impedance profiles and maps. This procedure was applied to 12 3D seismic lines (six cross-lines, and six in-lines) from Horus field in Western Desert in Egypt after converting them from analog state to SEGY format by vectorization. Five wells had been used in this study. The outcome of this paper is an improved subsurface image of seismic data and achieving the reservoir characterization in a good way.  相似文献   

Petrophysical characteristics of Wakar Formation, Port Fouad marine field, north Nile Delta, Egypt     

Adel Mohamed  Elkhedr Ibrahim  Ahmed Sabry 《Arabian Journal of Geosciences》2013,6(5):1485-1497

Petrophysical characteristics of the late Miocene Wakar Formation of Port Fouad Marine Field have been evaluated through the analysis of well-logging records of nine exploratory and development wells, distributed in the northeastern offshore area of the Nile Delta. These records have been analyzed through utilizing the ELAN Plus petrophysics software in order to identify the lithological constituents and fluid saturation parameters. The gas potentialities of the studied formation have been evaluated through number of isoparameteric maps. The litho-saturation analysis indicates that the Wakar Formation in the studied wells is mainly gas-bearing with some water-bearing sand levels. The analytical formation evaluation reveals that the lithological facies consists mainly of sandstone, shale, and siltstone. The disseminated shale is mainly of dispersed type and some of laminated habitat. It also points to the dominance of the intergranular porosity. The isoparametric maps of the petrophysical parameters show that the level S1 of Wakar Formation is the main reservoir.  相似文献   

Aeromagnetic data analysis using the 2D directional continuous wavelet transform (DCWT)     

Sid-Ali Ouadfeul  Mohamed Hamoudi  Leila Aliouane  Said Eladj 《Arabian Journal of Geosciences》2013,6(6):1669-1680

In this paper, we have analyzed the geomagnetic anomaly field reduced to the pole by the 2D directional continuous wavelet transform (DCWT). The objective is to identify geological contacts. The proposed idea has been applied firstly at a synthetic model, the obtained results showed the robustness of the proposed technique, after that the synthetic data has been noised; analysis shows that contacts identified by DCWT are affected by noise. To resolve this problem, we have proposed an algorithm to reduce the noise effect in the contacts model. Application on the real geomagnetic data of In Ouzzal area located in the West of Hoggar (Algeria) shows clearly the robustness of the proposed method. Comparison with the analytic signal solutions exhibits a difference between the two models of contacts. Our method gives results that are accurate with the structural geological map.  相似文献   

Environmental geochemistry of El Temsah Lake sediments, Suez Canal district, Egypt     

Ibtehal Fathy Mohamed 《Arabian Journal of Geosciences》2013,6(11):4145-4153

The heavy metal contents of Mn, Ni, Cu, Zn, Cr, Co, Pb, Cd, Fe, and V in the surface sediments from five selected sites of El Temsah Lake was determined by graphite furnace atomic absorption spectrophotometer. Geochemical forms of elements were investigated using four-step sequential chemical extraction procedure in order to identify and evaluate the mobility and the availability of trace metals on lake sediments, in comparison with the total element content. The operationally defined host fractions were: (1) exchangeable/bound to carbonate, (2) bound to Fe/Mn oxide, (3) bound to organic matter/sulfides, and (4) acid-soluble residue. The speciation data reveals that metals Zn, Cd, Pb, Ni, Mn, Cu, Cr, Fe, and V are sink primarily in organic and Fe–Mn oxyhydroxides phases. Co is mainly concentrated in the active phase. This is alarming because the element is enriched in Al Sayadin Lagoon which is still the main site of open fishing in Ismailia. Average concentration of the elements is mostly above the geochemical background and pristine values of the present study. There is a difference on the elemental composition of the sediment collected at the western lagoon (Al Sayadin Lagoon), junction, the shoreline shipyard workshops, and eastern beach of the lake. Depending upon the nature of elements and local pollution source, high concentration of Zn, Pb, and Cu are emitted by industrial wastewater flow (shoreline workshops), while sanitary and agricultural wastewater (El Bahtini and El Mahsama Drains) emit Co and Cd in Al Sayadin Lagoon. On the other hand, there is a marked decrease in potentially toxic heavy metal concentrations in the sediments at the most eastern side of the lake, probably due to the successive sediment dredging and improvements in water purification systems for navigation objective. These result show that El Temsah receives concentrations in anthropogenic metals that risk provoking more or less important disruptions, which are harmful and irreversible on the fauna and flora of this lake and on the whole ecobiological equilibrium.  相似文献   

Removal of zinc(II) from aqueous solutions using modified agricultural wastes: kinetics and equilibrium studies     

Zeid A. Al Othman  Mohamed A. Habila  Ali Hashem 《Arabian Journal of Geosciences》2013,6(11):4245-4255

In recent years, the need for safe and economical methods to eliminate heavy metals from contaminated waters has necessitated research on the production of low-cost alternatives to commercially available activated carbon. In the present work, in order to enhance the removal of heavy metals from contaminated water, Zizyphus vulgaris wastes were modified chemically to produce an adsorbent rich in carboxylic groups to enhance the removal of heavy metals from contaminated water. Adsorption of Zn(II) ions on the produced adsorbent was then optimized. The optimal ratio for esterification involved the treatment of Z. vulgaris wastes (1 g) with 0.0037 mmol malic acid in the presence of a very small amount of water for 2 h at 140 °C. The maximum values for adsorption capacity, q _max, were 28.7 and 164.6 mg/g on native and modified Z. vulgaris wastes, respectively, at pH 5 and 30 °C with a contact time 2 h and an initial metal ion concentration of 400 mg/L. The equilibrium data were well fitted by the Langmuir and Freundlich adsorption models and demonstrated the significant capacity for Z. vulgaris wastes in the removal of Zn(II) ions from aqueous solutions.  相似文献   

Runoff evolution in Macta basin (Northwest of Algeria)     

Meddi M. Mohamed  Amel Talia 《Arabian Journal of Geosciences》2013,6(1):35-41

In Algeria, the climate change in recent decades has a negative impact on water resources. The goal of this study is to determine the influence of these hazards on surface water resources in the basin of Macta (Northwest of Algeria). The study of climatic pulsations is implemented from the climate coefficient changes and its moving averages over 3 years. Variations of this coefficient based on years, for the period 1949–1973, show an alternation of wet and dry years. Starting from 1973, a very dry period of more than 20 years was installed in the basin, with deficits ranging from 22% to 72%. The consequences of the surface water deficit can damage the environmental balance and consequently affect the various human activities that are directly or indirectly related to the use of these resources.  相似文献   

Lateral variations of coda Q and attenuation of seismic waves in the Gulf of Suez, Egypt     

Mamdouh A. Morsy  Sherif El Hady  Salah M. Mahmoud  Enayat Abdel Moneim Awad 《Arabian Journal of Geosciences》2013,6(1):1-11

Gulf of Suez consists mainly of three tectonic provinces that are separated by two accommodation zones. The southern edge of the gulf is bordered by N–S faults which mark the transition between the shallow water, Suez Basin and the deep northern Red Sea Basin. The sensitivity of coda Q measurements with respect to geological differences in the crust is demonstrated in three regions with a large variety of tectonic and geologic properties. The estimation of coda Q (Qc) is performed for 370 local earthquakes recorded at 12 digital seismic stations during the period from 2000 to 2007. The magnitudes of the earthquakes between 1.5 and ~4.5 have been used at central frequencies 1.5, 3, 6, 9, 12, 15, 18, and 24 Hz through three lapse time windows 10, 20, 30 s starting at once and twice the time of the primary S wave from the origin time. The time domain coda decay method of the single isotropic scattering model is employed to calculate frequency-dependent values of coda Q. The Qc values are frequency dependent in the range 1–25 Hz, and are approximated by a least squares fit to the power law [Qc(f) = Qo(f/fo)η]. The observed coda Q indicates that the area is seismically and tectonically active with high heterogeneities. The variation of the quality factor Qc has been estimated at different regions to observe the effect of different tectonic province. The average frequency-dependent estimated relations of Qc vary from 65f1.1 to 96f0.9 at 10 to 30 s window length, respectively. The decreasing value of the frequency parameter with increasing lapse time shows that the crust acquires homogeneity with depth. The variation of Qc with the variations in the geologic and tectonic properties of the crust was investigated. The frequency exponent η might be larger in active tectonic areas and smaller in more stable regions. In the northern region of the Gulf of Suez, the obtained value of η?=?0.8?±?0.011, which might indicate a low level of tectonic activity compared with η?=?1.1?±?0.005 and 1.3?±?0.009 for the central and southern regions of the gulf.  相似文献   

Fault pattern delineation and structural interpretation of the Gafsa trough (onshore central Tunisia) using gravity data     

Mohamed Dhaoui  Hakim Gabtni 《Arabian Journal of Geosciences》2013,6(5):1559-1568

The purpose of this investigation was to identify subsurface lineaments in Gafsa trough (onshore central Tunisia) after gravity data analysis. The Bouguer and residual gravity maps show a gravity values decrease from west to east associated with subsidence variation and confirmed by a regional seismic reflection profile. The deep structural map of the study area is elaborated after the application of two methods: (1) the automatic lineament tracing after horizontal gravity gradient and (2) 3D Euler method. The dominant trends show approximately NW–SE, E–W, and NE–SW directions. Some of these trends are well correlated with the major faults systems. We can qualify the deep structuration model as a mosaic of quadratic blocks bounded by significant deep flower fault corridors. The elaborated structural map of the study area constitutes also a useful document for rationalizing the future petroleum exploration in the Gafsa trough.  相似文献   

Balneological study based on the hydrogeochemical aspects of the sulfate springs water (Hit–Kubaiysa region), Iraq     

Abed Salih Al Dulaymie  Bayan Muhie Hussien  Moshtaq Ahmed Gharbi  Husam Naji Mekhlif 《Arabian Journal of Geosciences》2013,6(3):801-816

This research examined the balneological characteristics of spring waters within the area of Abu-Jir Fault Zone throughout the hydrogeologic aspects explained by the setting of the hydrogeologic units including the water-bearing horizons of Euphrates, Ana, and Baba Formations. The groundwater flow in the hydrogeologic system correlated with the trends of enrichment or depletion case processes of mineralization (spatial distribution maps of TDS and other components) show different phenomena of groundwater source and interconnection, which helps in the classification springs into two potential site. The physicochemical characteristics of the water flow from springs indicate a hydrochemical approach throughout the spatial variation of important parameters (using Rockware software) related to the balneological study. The monitoring network of the spring waters performed by seven field measurements and 33 variables (totaling to 720 detected measurements) in 18 springs approved the after desk study and water point inventory using a GPS apparatus (GARMIN SUMMIT-e TREX). The study examined the integrated hydrogeological aspects and spring water properties for evolutions and the classification of minero-medicinal water. The traditional hydrochemical information of the spring waters and their sediment properties correlated with balneological limits (standards and definitions) are used in the selection of springs characterized by balneotherapeutic applications. A suggested screening and ranking technique has been developed for evaluating preferable springs selected for natural therapy. The application of ranking technique indicates four graded consequent preferable springs for balneotherapeutic investment: first grade spring represented by Kubaiysa spring (S-4); second grade springs represented by Tawila spring (S-12); third grade springs represented by Mamora spring (S-15), Arnab spring (S-10), Zazoe spring (S-5), and Maqtoom spring (S-13); and fourth grade springs represented by Khalidiya spring (S-16) and Layeg spring (S-7).  相似文献