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Bassam A. ABUAMARAH Mokhles K. AZER Paul D. ASIMOW Habes GHREFAT Heba S. MUBARAK 《《地质学报》英文版》2021,95(2):459-480
The Abu Dabbab albite granite(ADAG), in the central Eastern Desert of Egypt, hosts the most significant rare metal ore deposit in the northern part of the Neoproterozoic Arabian-Nubian Shield. Here, we report detailed field,petrographic, mineralogical and geochemical investigation of the ADAG, an isolated stock-like granitic body with sharp intrusive contacts against metamorphic country rocks, probably emplaced at about 600 Ma. The fine-grained porphyritic upper unit is a preserved remnant of the shallowly-emplaced apex of the magma chamber, whereas the medium-grained lower unit crystallized at deeper levels under subvolcanic conditions. The peraluminous leucocratic ADAG shares common geochemical characteristics with post-collisional intraplate A-type magmas. In addition to the conspicuous enrichment in Na2 O, the ADAG is remarkable for its anomalous concentrations of Ta, Nb, Li, Hf, Ga, Sn, Zn and heavy rare-earth elements. Nb-Ta minerals in the ADAG are mixed with Fe-Mn oxides, forming black patches that increase in abundance toward of the base of the intrusion. Columbite-tantalite, cassiterite and wolframite are the most important ore minerals.Pronounced negative Eu anomalies(Eu/Eu* = 0.10–0.24) reflect extreme magmatic fractionation and perhaps the effects of late fluid-rock interaction. The ADAG was most likely generated by partial melting of the juvenile middle crust of the ANS as the geotherm was elevated by erosional uplift following lithospheric delamination and it was emplaced at the intersection of lineations of structural weakness. Although formation of the ADAG and its primary enrichment in rare metals are essentially due to magmatic processes, late-stage metasomatism caused limited redistribution of rare metals. Fluid-driven subsolidus modification was limited to the apex of the magma chamber and drove development of greisen, amazonite, and quartz veins along fracture systems. 相似文献
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Abd el-aziz Khairy Abd el-aal Yuji Yagi Heba Kamal kamal Abdelrahman 《Arabian Journal of Geosciences》2016,9(4):322
In this study, an integrated multi-channel analysis of Surface Waves (MASW) technique is applied to explore the geotechnical parameters of subsurface layers at the Zafarana wind farm. Moreover, a seismic hazard procedure based on the extended deterministic technique is used to estimate the seismic hazard load for the investigated area. The study area includes many active fault systems along the Gulf of Suez that cause many moderate and large earthquakes. Overall, the seismic activity of the area has recently become better understood following the use of new waveform inversion method and software to develop accurate focal mechanism solutions for recent recorded earthquakes around the studied area. These earthquakes resulted in major stress-drops in the Eastern desert and the Gulf of Suez area. These findings have helped to reshape the understanding of the seismotectonic environment of the Gulf of Suez area, which is a perplexing tectonic domain. Based on the collected new information and data, this study uses an extended deterministic approach to re-examine the seismic hazard for the Gulf of Suez region, particularly the wind turbine towers at Zafarana Wind Farm and its vicinity. Alternate seismic source and magnitude-frequency relationships were combined with various indigenous attenuation relationships, adapted within a logic tree formulation, to quantify and project the regional exposure on a set of hazard maps. We select two desired exceedance probabilities (10 and 20 %) that any of the applied scenarios may exceed the largest median ground acceleration. The ground motion was calculated at 50th, 84th percentile levels for both selected probabilities of exceeding the median. 相似文献
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Fate of drilling waste discharges and ecological risk assessment in the Egyptian Red Sea: an aquivalence-based fuzzy analysis 总被引：2，自引：2，他引：0
Ahmad Agwa Heba Leheta Ahmed Salem Rehan Sadiq 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(1):169-181
Egypt is located in the Northeast of Africa where oil and gas (O&G) are produced offshore from the Gulf of Suez and the Southeast part of the Mediterranean. The O&G production in Egypt is distributed as follows: 70% from Gulf of Suez, 16% from Western desert, 8% from the Sinai Peninsula and 6% from Eastern desert. Past O&G activities, refining and transport have resulted in chronic pollution in Egyptian offshore and numerous environmental programs have been initiated to protect new development areas from the environmental impacts. The offshore drilling process uses drilling fluids (mud) and generates waste fluids and cuttings, which could be the largest discharges going into the receiving water bodies. There are several options to manage offshore drilling wastes: offshore discharge, offshore down-hole injection and onshore disposal. Water-based drilling fluids (WBF) are commonly employed for drilling in Egyptian offshore because of their expected environmental benign behavior. The main objective of this paper is to develop a methodology to determine the fate of heavy metals associated with WBF drilling waste in the marine environment and estimate the associated ecological risks. Proposed contaminant fate model is based on an aquivalence approach, which has been integrated with fuzzy-based analysis to study the uncertainties. This research concluded that the impacts of heavy metals associated with the drilling waste discharges in the receiving waters are minimal. 相似文献
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Stefania Venturi Franco Tassi Orlando Vaselli Georges E. Vougioukalakis Heba Rashed Christos Kanellopoulos Chiara Caponi Francesco Capecchiacci Jacopo Cabassi Andrea Ricci Luciano Giannini 《Natural Hazards》2018,90(2):601-621
Rip currents are fast moving, offshore flows that have the ability to move even the strongest swimmers into deeper waters. Miami Beach, Florida is one of the most visited beaches in the USA and a sought after destination for citizens and international tourists alike. It is also known to be a rip current “hot spot.” These factors greatly increase the risk of drowning; however, no previous research has focused on beachgoer perception of rip-related risks in South Florida. Over a 12-month period, 203 public surveys were collected to determine the rip current knowledge of beachgoers at Miami Beach based on factors such as swimming ability and frequency of beach visits. The responses were analyzed by constructing a normalized component factor to determine the respondent’s comprehensive knowledge of rips, and multiple regression models were used to assess the net influences of sociodemographic and behavioral characteristics on the responses. A significant proportion of the survey respondents showed insufficient knowledge, indicating they are at risk of drowning in a rip current. Frequent beachgoer’s exposure to the beach environment, maturation, and nativity is identified as the main contributors to knowledge net of other sociodemographic compositions. The most at-risk groups were determined to be young adults, foreign tourists, poor swimmers, and those who infrequently visited the beach. Miami Beach needs to initiate a rip current safety campaign to target these at-risk beachgoers, where interventions beyond familial and educational institutions should be introduced. 相似文献
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Awadh Salih Muhammad Al-Mimar Heba S. Yaseen Zaher Mundher 《Natural Resources Research》2021,30(6):4403-4415
Natural Resources Research - This research was conducted on five oilfields in the Mishrif reservoir, southern Iraq, to illustrate the effects of permeability on the damage caused by the injection... 相似文献
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Salih Muhammad Awadh Heba S. Al-Mimar Abdullah A. Al-Yaseri 《Arabian Journal of Geosciences》2018,11(18):552
Cation and anion concentrations and boron isotopic ratio of brines in the Mishrif Formation (U. Campanian-Tuoronian) from North Rumaila, South Rumaila, Majnoon, Zubair, and West Qurna oilfields southern Iraq were investigated. The aims of this study are to define the type, origin of the oilfield waters, and its flow model in the subsurface oil traps. Mishrif brines are characterized by having higher concentrations of sodium (50,500–84,200 ppm), chlorine (102,100–161,500 ppm), and boron (21.9–31.1 ppm) with lower sulfate contents (187–1350 ppm) relative to the modern seawater. Samples have slightly depleted in δ 11B (35.4‰) relative to seawater fall near the seawater intrusion of the diagram Cl/Br Vs δ 11B and occupied the field of evaporated seawater on the diagrams of Cl vs B and 1/Br vs δ 11B. The brine of Na-chloride type is characteristics of the Mishrif reservoir in all oilfields except WQ which defined by facies of Na-Ca-chloride type. A weak acidic brine of a salinity six-time greater than seawater plays a role in generating the formation pressure and controlling the fluid flow. The reservoir rock-fluid interactions were interpreted using boron isotopes which eventually reveal an ongoing dilution process by the present seawater intrusion and injection water used for the secondary production under conditions of high-temperature digenetic reactions. The 11B in the oilfield water is resulted from uptake of the tetrahedral borate after precipitation of calcium carbonate, while 10B is sourced from the thermal maturation of organic matters. 相似文献
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