Palynostratigraphy and palaeoenvironmental significance of the Cretaceous palynomorphs in the Qattara Rim-1X well,North Western Desert,Egypt     

Maher I. El-Soughier  Amr S. Deaf  Magdy S. Mahmoud 《Arabian Journal of Geosciences》2014,7(8):3051-3068

Palynological and palynofacies analyses were carried out on some Cretaceous samples from the Qattara Rim-1X borehole, north Western Desert, Egypt. The recorded palynoflora enabled the recognition of two informal miospore biozones arranged from oldest to youngest as Elaterosporites klaszii-Afropollis jardinus Assemblage Zone (mid Albian) and Elaterocolpites castelainii–Afropollis kahramanensis Assemblage Zone (late Albian–mid Cenomanian). A poorly fossiliferous but however, datable interval (late Cenomanian–Turonian to ?Campanian–Maastrichtian) representing the uppermost part of the studied section was also recorded. The palynofacies and visual thermal maturation analyses indicate a mature terrestrially derived organic matter (kerogen III) dominates the sediments of the Kharita and Bahariya formations and thus these two formations comprise potential mature gas source rocks. The sediments of the Abu Roash Formation are mostly dominated by mature amorphous organic matter (kerogen II) and the formation is regarded as a potential mature oil source rock in the well. The palynomorphs and palynofacies analyses suggest deposition of the clastics of the Kharita and Bahariya formations (middle Albian and upper Albian–middle Cenomanian) in a marginal marine setting under dysoxic–anoxic conditions. By contrast, the mixed clastic-carbonate sediments of the Abu Roash Formation (upper Cenomanian–Turonian) and the carbonates of the Khoman Formation (?Campanian–Maastrichtian) were mainly deposited in an inner shallow marine setting under prevailing suboxic–anoxic conditions as a result of the late Cenomanian and the Campanian marine transgressions. This environmental change from marginal to open (inner shelf) basins reflects the vertical change in the type of the organic matter and its corresponding hydrocarbon-prone types. A regional warm and semi-arid climate but with a local humid condition developed near/at the site of the well is thought to have prevailed.  相似文献   

Hydrocarbon source potential of the Jurassic sediments of Salam-3X borehole,Khalda Concession,Northern Western Desert,Egypt     

Adel W. Felestteen  Maher I. El-Soughier  Mustafa S. Mohamed  Mostafa N. S. Monged 《Arabian Journal of Geosciences》2014,7(9):3467-3480

A total of 51 samples, collected from the Jurassic sediments (Ras Qattara, Yakout, Khatatba, Masajid, and Alam El Bueib (member 6) formations) of Salam-3X well, were subjected to organic geochemical analysis. Of the samples, nine have been subjected to palynofacies investigation. Based on the sedimentary organic matter, these sediments show only one palynofacies type, indicating the presence of gas- and oil-prone source rocks and reflecting deposition under marginal dysoxic–anoxic to shelf-to-basin transition conditions. The total organic content of the samples analyzed is characterized by a wide range of content, including fair, good, very good, and excellent. The organic matter quality of these samples is concentrated around types III (gas prone), III–II (gas and oil prone), and II (oil prone), reflecting gas- and oil-prone sediments, with a tendency to generate gas rather than oil; the result matches with the palynological analysis data. The temperature of maximum pyrolytic hydrocarbon generation of analyzed samples are ranging between 440 and 457 °C, reflecting thermally mature organic matter.  相似文献   

Palynological evidences on paleoclimate and paleoenvironmental changes during Holocene of Al-Hussaynia District,Central Iraq     

Maysoon Omar Ali 《Arabian Journal of Geosciences》2014,7(2):589-595

This paper is concerned with the study of paleoclimate and paleoenvironmental changes of Hussaynia township which is located in Karbala at the center of the Mesopotamian plain during Holocene. Ten soil samples were examined to determine their content of pollens, spores, and marine organisms (dinoflagellates). These palynomorphs include: Graminidites, Palmaepollenites, Chenopodiaceae, Composita, Cyperaceae, Sphaginum sporites, Pinus pollenites, Convovolus, Artimesia, Laevigatosporites, Quercus, dinoflagellates, and fungi. The study revealed climatic and environmental changes in the area during Holocene and four climatic zones were determined in the studied sequence and correlated with other areas in and outside of Iraq. The climate was pluvial with intervening dry periods in the 10000 years?bp. The study indicated as well, some marine effects on the studied area on the commencement of Holocene due to the global transgression. This is based on the presence of marine organisms, dinoflagellate.  相似文献   

Manifestation of Remote Sensing Data in Modeling Urban Sprawl Using the SLEUTH Model and Brute Force Calibration: A Case Study of Sana’a City, Yemen     

Mohamed Al-shalabi  Biswajeet Pradhan  Lawal Billa  Shattri Mansor  Omar F. Althuwaynee 《Journal of the Indian Society of Remote Sensing》2013,41(2):405-416

Sana’a the metropolitan capital of Yemen, has experienced rapid spatial growth and uncontrolled development for decades. In the absence of a means to forecast and predict urban growth trends, planning and urban policy decisions have been found wanting. In this study the SLEUTH (Slope, landuse, exclusion, urban extent, transportation and hillshade) model which has been widely and successfully applied in developed countries, has been applied to predict the spatial urban sprawl pattern from 2004–2020 in Sana’a. This was to provide the necessary forecast for better planning and decision making. The model performed well as per the calibration coefficient values. The results showed that there will a 29 % increase in spatial urban sprawl growth during the modeling period. Growth of the sprawl will be mainly at the edges of the urban boundary, there will also be a wide area of scattered urban clusters. Factors that will have major influence on spatial expansion of the city will be diffusion, natural and internal growth, slope (that will hinder spread) and transportation (along which most of the urban sprawl will occur). The study also provides an insight into how the SLEUTH model performs in a poorly planned urban environment as compared to the planned and controlled environment where it has been applied.  相似文献   

Everyday law on the streets: city governance in an age of diversity (Mariana Valverde)     

Tim Maher 《Urban geography》2013,34(3):471-472

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GEOLOGY AND STRUCTURAL CONTROLS ON SOME OF REE AND POLYMETALIC Nb-Zr-Ta DEPOSITS-BEARING ALKALINE-PERALKALINE ROCKS IN THE ARABIAN SHIELD, KINGDOM OF SAUDI ARABIA     

Maher A. El Amawy  Ghazi A. Kattu  Hassan M. Al Marzouki 《《地质学报》英文版》2013,87(Z1):750-751

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Methodology and applications for the benefit cost analysis of the seismic risk reduction in building portfolios at broadscale     

Jairo A. Valcárcel  Miguel G. Mora  Omar D. Cardona  Lluis G. Pujades  Alex H. Barbat  Gabriel A. Bernal 《Natural Hazards》2013,69(1):845-868

This article presents a methodology for an estimate of the benefit cost ratio of the seismic risk reduction in buildings portfolio at broadscale, for a world region, allowing comparing the results obtained for the countries belonging to that region. This methodology encompasses (1) the generation of a set of random seismic events and the evaluation of the spectral accelerations at the buildings location; (2) the estimation of the buildings built area, the economic value, as well as the classification in structural typologies; (3) the development of vulnerability curves for each typology; (4) the estimation of the annual average loss of the buildings portfolio in the current conditions as well as in the case of a hypothetical structural intervention. The benefit cost ratio is estimated as the difference between the estimates of the present value of these two annual average losses, divided by the retrofitting costs. This methodology has been applied to the portfolio of public schools of 14 countries of Latin America and the Caribbean, for evaluating the feasibility of the seismic risk reduction at a national scale.  相似文献   

Assessment of groundwater quality and its suitability for drinking and agricultural uses in arid environment     

Omar Ali Al-Khashman  Aiman Qasem Jaradat 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(3):743-753

Groundwater quality in Ma’an area was evaluated for its suitability for drinking and agricultural uses by determining the main physical and chemical properties during a 1 year survey study (August 2009 to August 2010). Several samples were collected from ten different wells and analysed for temperature, pH, conductivity, total dissolved solids, total hardness, major cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺), major anions (HCO₃ ^?, Cl^?, NO₃ ^?, SO₄ ^2?, F^? and Br^?) and trace metals (Fe²⁺, Al³⁺, Mn²⁺, Cu²⁺, Zn²⁺, Pb²⁺ and Cd²⁺). The general chemistry of water samples was typically of alkaline earth waters with prevailing bicarbonate chloride. The results showed great variations among the analyzed samples with respect to their physical and chemical parameters. However, most values were below the maximum permissible levels recommended by Jordanian and WHO drinking water standards. The quality assessment shows that in general, the GW in the study area is not entirely fit for direct drinking with respect to EC, and Pb²⁺. According to the residual sodium carbonate and sodium adsorption ratio, the water in the studied wells can be used for irrigational purposes.  相似文献   

Hydrological effects of the increased CO2 and climate change in the Upper Mississippi River Basin using a modified SWAT   总被引：1，自引：0，他引：1  

Yiping Wu  Shuguang Liu  Omar I. Abdul-Aziz 《Climatic change》2012,110(3-4):977-1003

Increased atmospheric CO₂ concentration and climate change may significantly impact the hydrological and meteorological processes of a watershed system. Quantifying and understanding hydrological responses to elevated ambient CO₂ and climate change is, therefore, critical for formulating adaptive strategies for an appropriate management of water resources. In this study, the Soil and Water Assessment Tool (SWAT) model was applied to assess the effects of increased CO₂ concentration and climate change in the Upper Mississippi River Basin (UMRB). The standard SWAT model was modified to represent more mechanistic vegetation type specific responses of stomatal conductance reduction and leaf area increase to elevated CO₂ based on physiological studies. For estimating the historical impacts of increased CO₂ in the recent past decades, the incremental (i.e., dynamic) rises of CO₂ concentration at a monthly time-scale were also introduced into the model. Our study results indicated that about 1–4% of the streamflow in the UMRB during 1986 through 2008 could be attributed to the elevated CO₂ concentration. In addition to evaluating a range of future climate sensitivity scenarios, the climate projections by four General Circulation Models (GCMs) under different greenhouse gas emission scenarios were used to predict the hydrological effects in the late twenty-first century (2071–2100). Our simulations demonstrated that the water yield would increase in spring and substantially decrease in summer, while soil moisture would rise in spring and decline in summer. Such an uneven distribution of water with higher variability compared to the baseline level (1961–1990) may cause an increased risk of both flooding and drought events in the basin.  相似文献   

Reintegrating nanogranitoid inclusion composition to reconstruct the prograde history of melt-depleted rocks     

Omar Bartoli 《地学前缘(英文版)》2019,10(2):517-525

A recent fascinating development in the study of high-grade metamorphic basements is represented by the finding of tiny inclusions of crystallized melt(nanogranitoid inclusions) hosted in peritectic phases of migmatites and granulites. These inclusions have the potential to provide the primary composition of crustal melts at the source. A novel use of the recently-published nanogranitoid compositional database is presented here. Using granulites from the world-renowned Ivrea Zone(NW Italy) on which the original melt-reintegration approach has been previously applied, it is shown that reintegrating melt inclusion compositions from the published database into residual rock compositions can be a further useful method to reconstruct a plausible prograde history of melt-depleted rocks. This reconstruction is fundamental to investigate the tectonothermal history of geological terranes.  相似文献