Exploration of copper deposits in Wadi El Regeita area, Southern Sinai, Egypt, with contribution of remote sensing and geophysical data     

S. M. Salem  Sultan Awad Arafa  T. M. Ramadan  El Sayed A. El Gammal 《Arabian Journal of Geosciences》2013,6(2):321-335

Three types of hydrothermal alterations are recorded in Wadi El Regeita area, argillic, phyllic, and propylitic. Whole-rock analysis of representative samples of the alteration halo (1) shows a Cu, Au, and Ag content up to 1.7 wt.%, 1.6 g/t, and 4 g/t, respectively; in the alteration halo (2), these metal contents are up to 1.3 wt.%, 1.4 g/t, and 3 g/t, following the same order. The integrated remote sensing and geophysical data, as well as geological field verification, show that Wadi El Regeita area includes promising Cu ores within two hydrothermal alteration haloes. Spatial data analyses of lineaments from Landsat Enhanced Thematic Mapper (ETM) band ratio image (7/5, 5/4, 3/1) reveal the presence of alteration haloes that potentially may host Cu mineralization at south and north of El Regita Cu mine. Gravity interpretation indicates that the surveyed area is dissected by NE–SW fault zones in the central part, near Wadi El Regeita Cu mine. Ground magnetic survey data revealed that the surveyed area includes six magnetic bodies at depths ranging from 32 to 90 m, possibly recording the presence of mineralized and hydrothermally altered andesitic dykes. The half length of these dykes ranges from 600 to 1,070 m; their half thickness from 30 to 123 m and their half width from 48 to 531 m. Dyke locations coincide with surface alteration haloes (1) and (2) as indicated by the ETM band ratio image processing. The final assessment of the area, however, needs more detailed geological and geophysical studies with contributions of remote sensing techniques.  相似文献   

The utilization of seismic interpretation to identify and describe the shallow subsurface structures in the southeastern Mediterranean Sea     

Mohamed Omran  El Sayed Selim  Hatem Aboelkhair 《Arabian Journal of Geosciences》2013,6(10):3749-3764

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   

Focal mechanism of Badr earthquake, Saudia Arabia of August 27, 2009     

Khalid S. Aldamegh  Hesham Hussein Moussa  S. Nasser Al-Arifi  Sayed S. R. Moustafa  Moustafa Hemeda Moustafa 《Arabian Journal of Geosciences》2012,5(4):599-606

Focal mechanism solution of the 27th August 2009 earthquake (mb?=?4.0) that occurred in the Badr area, northwest of Saudi Arabia, approximately 50?km from the Red Sea has been determined from the P-wave first motion polarities. Results show normal faulting mechanism with a negligible component of strike-slip motion with NE T-axis direction. This type of mechanism is common with other earthquakes of the northwestern Saudi Arabia and is considered to present the tectonic movement of the region. The dominantly extensional tectonic regime in this province demonstrates the influence of NE extension in the Red Sea. The strikes of the solution are consistent with those of the main faults near the epicenter. Hypocentral location of this earthquake was carried out using the data from the King Abdulaziz City of Science and Technology Seismic Network, Saudi Arabia, and the Egyptian National Seismological Network, Egypt. The horizontal and vertical confidence estimates are 0.5?km for both. The local magnitude, M _L, following the Richter??s original definition was also derived from ten digital three-component broadband seismograms. The average local magnitude determined in this study is 3.8?±?0.17. The estimated seismic moment of this event is $ {3}.{\hbox{7e}} + {14}\,{\hbox{Nm}}\left( {{M_{\rm{W}}} = {3}.{66}\pm 0.0{7}} \right) $ .  相似文献   

Characteristic features of salt tectonics offshore North Sinai, Egypt     

El Sayed Ibrahim Selim  Mohamed A. Omran 《Arabian Journal of Geosciences》2012,5(3):371-383

Salt tectonic along offshore North Sinai was studied using seismic reflection data. The study revealed and identified various types of salt tectonics and structures in the study area. The triggering mechanism of salt tectonics was attributed to the pressure regime initiated from overloading sediments on the Messinian evaporites. The sediment load of 3,000?m exceeds the critical load (more than 1,000?m) and hence creates a pressure zone. The salt-generated structures resulted from thin-skinned extension that is driven by gravity gliding of the overloading sediments above the Messinian evaporite boundary, which acts as a detachment layer. These structures comprise normal growth faults and keystone grabens, trending roughly perpendicular to the slope of the continental margin. Salt tectonics in the study area were also triggered by the deformation of the movement of evaporite layer that causes stretching and fragmentation of the evaporite layer. Moving salt layer took place laterally and vertically, causing lateral and vertical pressures inside the Pliocene sediments. These movements of sediments led to the formation of salt rollers, salt weld, salt diapirs, rollover structures, and fault blocks. The interpretation of seismic data illustrates that the evaporite layer was switched off between the famous reflector M at its top and another reflector N at its base. M reflector is present and can be traced across the whole study area, while the N reflector pinched out in some parts of the study area.  相似文献   

The use of seismic interpretation for delineating the characteristic features of Messinian channels in the north Nile Delta, Egypt     

El Sayed Ibrahim Selim 《Arabian Journal of Geosciences》2012,5(4):713-722

Abu Madi Messinian Formation occupied a prominent issue as the most exploratory target in the search for natural gas in the Nile Delta. Interpretation of the available onshore seismic reflection data of the northeastern part of the Nile Delta reveals that there is a series of troughs, depressions, and mounded structures within the Abu Madi Formation (Messinian time). Onlap, downlap, and truncation relationship of reflections were observed very close to fault locations in the Miocene time. Many channels have been imaged clearly and described on the seismic reflection data of the onshore Nile Delta. The depths to these channels range between 2.5?s in the southeast to 3.1?s (t.w.t.) while their width ranges from 1?km to more than 5?km. These channels were formed by two factors: (1) submarine erosion and redeposition, during the relative sea level falls and (2) tectonic effect. Many of these channels followed more or less the trends of the historic branches of the ancient Nile Delta. The classification of these channels is based on some factors: (1) channel morphology (depth and width), (2) channel shape, and (3) tectonic effect.  相似文献   

Modeling of thermal pollution in coastal area and its economical and environmental assessment     

M. Abbaspour  A. H. Javid  P. Moghimi  K. Kayhan 《International Journal of Environmental Science and Technology》2005,2(1):13-26

The Persian Gulf is one of the aquatic ecosystems which has recently faced with different pollutions. Cooling water discharges due to various industries such as power plants can cause important disorders on present ecosystem balance because of its high temperature. Obviously, due to thermal pollution, a great number of aquatic creatures face with a new situation that they can not tolerate. Thermal pollution leads to their migration, creates a potential for new coming species which in turn can thoroughly change the marine ecosystem feature. The other impacts of this phenomenon are: disorders in reproduction, nourishment and other biological habits. In this research, thermal pollution due to Bandar Abbas Thermal Power Plant (BATP) development plan was modeled using MIKE21 software. In order to avoid a decrease on the power plant efficiency in development plan, the distance between inlet and outlet was determined by comparing the results of different scenarios and economical aspects. After determining the distance between inlet and outlet, the water temperature in the coastal area was compared with standards of Iranian Department of the Environment (DOE). The model results represent that the water temperature, in Bandar Abbas coastal area, exceeds than the permissible limit (3 °C) in a distance equal to 200 m. far from the discharging location, and in order to reduce its harmful impacts, some suggestions are made to reduce the associated thermal pollution.  相似文献   

Trifactorial interactive effects of nutrients, water potential and temperature on carbohydrate allocation to the embryonic axis of desert plant seeds     

H.M El-Sharkawi  K.A Farghali  S.A Sayed 《Journal of Arid Environments》1997,35(4):655-664

Seeds ofProsopis juliflora, Calotropis proceraandSorghum × drummondiiseeds were subjected to trifactorial treatment combinations of: nutrients (Nr), temperature (T) and reduced water potential (ψ_m) in their incubation medium. The embryonic axis and storage tissue of germinating seeds were analysed for soluble sugars (SS) and hydrolysable carbohydrates (HC). Allocation of both carbon fractions in germinating seed organs was variously affected by single factors and their mutual interactions. Differences in such effects included both magnitude and relative role of each factor or interaction, the effect also being organ and/or species dependent. The interaction φ_m× T had the predominant role in changes of both SS and HC content and their allocation in seed organs, while the interaction Nr × φ_m× T had a subdominant role. Nutrients in the medium generally induced significantly higher SS and HC content in whole seeds at low water potentials, the level of which is temperature dependent (indicating interactive effects between single factors). Also, nutrients generally increased translocation of SS to the radicle (hence, allocation of HC), improving its capacity of water uptake through increased osmolarity.  相似文献   

A Study of Linke Turbidity Factor over Qena / Egypt     

Sayed M. Elshazly 《大气科学进展》1996,13(4):519-532

Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar radiation (I),which are calculated from global (G) and diffuse (D) - solar radiation measurements.Monthly and seasonally variations of both diurnal and daily average values of TL (m) increases steadily in the direction of sunset in the months from June to December 1992 as well as Summer and Autumn seasons,while it falls generally in this direction for the months from January to March and Winter season.In April and May,TL (m) fluctuates obviously through the day hours,it is also shown that the average values of TL(m) are particularly large during Summer months compared to other months of the year.This behavior of TL(m) is discussed in view of the variations of some weather elements,which affect the content of water vapor and dust particle in the atmosphere of the study region.It seems t be of s  相似文献   

Assessment of in situ permeability with emphasis on packer testing in Kuwait     

Mohammad A. Mollah  Shabbir A.S. Sayed 《Engineering Geology》1995,39(3-4):217-231

This paper discusses in situ permeability testing performed at two sites in bore holes drilled in an extensive hydrogeological exploration program in Kuwait. The testing program, comprising packer, falling and rising head tests, was carried out in calcareous and variedly textured cemented sand formed during post-depositional diagenetic processes with the colloquial name ‘Gatch’. The program was undertaken to assist in the design and construction of a pilot drainage scheme aimed at lowering of the groundwater table in Kuwait City and suburbs.

The results indicated that ‘Gatch’ is an almost impermeable soil. However, the hydraulic conductivity of the subsoils at the investigated sites is significantly influenced by the distribution and volume of macropores. These permeable zones act as preferential pathways for the movement of water bypassing the fine matrix and, thereby, improve markedly the overall drainage characteristics of the sites.

Various in situ test methods, including packer, compare results satisfactorily, to give the sites a variable hydraulic conductivity rating that straddles between very low and medium. The packer device, by faring well against other routine in situ tests, shows promises for use as a tool in the assessment of drainage parameters of cemented soils. Laboratory tests, performed in parallel, proved inadequate to characterize the permeability properties of the subsoils in Kuwait.  相似文献   

AUTOMATED ANALYSIS OF PUMPING TESTS IN UNCONFINED AQUIFERS OF SEMI-INFINITE THICKNESS     

Shabbir A. S. Sayed 《Ground water》1990,28(1):108-112

Abstract A procedure is described for automated fitting of test data for pumping from an unconfined aquifer of semi-infinite thickness. The fitting is achieved by sensitivity analysis and the least-squares method. The early time data are fitted to the Streltsova (1974) model and the late time data are matched to the Dagan (1967) model. These solutions are useful where the aquifer thickness is extensive and unknown. Data from a test in the Indus Basin, Pakistan, was analyzed to test this procedure.  相似文献