The sedimentary pattern of the southern Gulf of Suez, Egypt, especially during the Cenozoic rift stage, was controlled mainly by tectonic activities (subsidence and uplift) and sea level change. The stratigraphic record of the southern Gulf of Suez can be divided into two megasequences: pre-rift and syn-rift. The pre-rift megasequence can be viewed as two distinctive depositional regimes, clastic rocks of continental to braided stream environment during Cambrian and open marine transgression extended from Upper Cretaceous till Eocene. The syn-rift deposits showed a distinctive contrast between the depocenter and peripheral basins. This difference can be shown clearly on the sedimentary sequence of Hilal and Shoab Ali oilfields. The syn-rift megasequence can be differentiated in relation to rift evolution into the following stages: initial rift stage with low subsidence rate, main rift stage with maximum subsidence rate, quiescence stage with the slowest subsidence rate throughout the rift evolution, evaporite stage with restriction conditions, and Pliocene–Recent stage with shallow marine condition. 相似文献
The Sinai Peninsula constitutes an important district of the Egyptian lands where it forms a triangular portion in northeastern Egypt. The southern Sinai metamorphic complexes are the northern uppermost part of the Arabian–Nubian Shield revealing the upper and middle crust from the East African Orogeny, in which they tectonically evolved. The Feiran–Solaf metamorphic complex (FSMC) of Sinai, Egypt is one of the highest grades metamorphic complexes of a series of basement domes that trends NW and crops out throughout the Arabian–Nubian Shield. The main aim of the present study is to apply the geospatial technology and to represent the capability of the geospatial technology to estimate the combined influence of lithology and structure studies, and to construct the lithological and structural maps of FSMC. Furthermore, detailed structural analysis is carried out to reveal the different ductile and brittle deformational events and proposed the tectonic evolutionary model for the study area. Mainly geospatial technology and structural analysis software have been used to go well with the aim of the present study. Developing specific image processing of satellite images and structural analysis were succeeded to discriminate the various lithological rock units, and the geological structural features of the FSMC, using geographic information system tools to construct the different thematic maps, were extracted. The present detailed investigations of the enhanced satellite images, structural analysis, and field verification reveal that the FSMC reached its present tectonic setting through more than four deformational phases concluding that the Pan-African Najd Fault System continued in Sinai and was reactivated during Red Sea tectonics as indicated by the dextral shear zone (Rihba) bordering the northern side of the FSMC. 相似文献
The SEM-EDX technique was applied to investigate Au, and Cu+Sn alloyed grains in the mineralization of the Um Shashoba mine for achieving further understanding of occurrences, internal structures and microchemistry of Au and Cu alloys and associated minerals, and mineralization type. This study is aiming at the genetic history of ore-bearing fluid events, geochemical evaluation and exploration significance. The results showed that the mineralization could be considered as a single major episode generated by metamorphic mesothermal solution rich in sulfides and unsaturated respect to Au. It was differentiated into many stages; started with formation of auriferous pyrite that was pseudomorphed by secondary hematite, limonite and goethite. Three phases of Au alloy were precipitated, and Cu+Sn and Ag-rich alloys were produced respectively and followed by deposition of two generations of barren pyrite. Calcite and ankerite were crystalized, surrounded and partially replaced some of early formed minerals. Finally, barren muscovite recrystallized around and inside both later formed carbonate minerals that were free of any sign of Au in their structures. The processes of deformation, recrystallization, annealing, dissolution, remobilization and re-precipitation played the most important roles in the genetic history of the mineralization. 相似文献
正1 Introduction There is now ample evidence of the impacts of the recent climate change and anthropogenic activities on different saline lake ecosystems.All over the world salt lakes are threatened by climate change,water diversions upstream for agricultural purposes,watershed changes,introduction of aliens,etc.that result in catastrophic 相似文献
We calculate the energy and momentum distributions associated with a Gödel-type space–time, using the well-known energy–momentum complexes of Landau–Lifshitz and Møller. We show that the definitions of Landau–Lifshitz and Møller do not furnish a consistent result. 相似文献
This study evaluates the potential use of cement-kiln dust (CKD), a waste product from the cement industry, for enhancing the mechanical as well as the hydraulic properties of soils in arid lands. Stabilized products will play a major role in reducing slope failures, pavement damage and the design of containment barriers for hazardous waste in arid lands. Various tests to determine the different physical properties of the stabilized matrix were conducted and the optimum mixture that produces maximum internal energy and minimum hydraulic conductivity was selected. The effect of soaking and unsoaking of the treated specimens on the mechanical properties was also evaluated. The effect of metal ion concentration and conjugate anions on the resultant hydraulic conductivity was evaluated. The optimum percentage of CKD was calculated by using stress-strain data, Newton's divided difference and Simpson's integration technique. The analyses have shown that 6% by weight of CKD is the optimum mix design, which increases the shear strength and decreases the hydraulic conductivity to less than 10-9 m/s. Therefore, the treated soil could be used as a soil-based barrier layer for containment of hazardous waste. 相似文献
Landslides - This work aims to develop a Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) in-house code for modelling landslide–water interaction problems. While we consider the... 相似文献
In the context of major outcomes of a steadily changing climate, extreme climatic conditions and the associated events in various forms of weather-related natural disasters, e.g. droughts, floods, and heat waves, are more frequently experienced on the global scale in recent years. In support of this argument, there are adequate numbers of explicit signals over such a persistent outlook, which is greatly illustrated by historical data and observations. This study, which is mainly oriented to investigating the drought behaviour in Thracian, Aegean and Mediterranean transects of Turkey's major river basins, is actually inspired by the foreseen potential of using annual maximum drought severity series (based on drought definition through the standardized precipitation index (SPI)) within a framework that resembles the use of flood discharge directly from flow measurements in a river basin. To this end, a series of spatial analyses were employed to identify different aspects of flood appearance in the study extent, including trend views on annual average drought severity series, shifts in the starting time of the annually most severe flood periods, and changes in spatial coverage views of average drought conditions under different drought severity categories. The framework of the analytical approaches depends greatly on validated international datasets and open-source computational algorithms. The results from the analyses that were conducted in two consecutive periods of 1958–1980 and 1981–2004 revealed that Turkey's western and southern river basin systems seemed to have experienced quite different behaviours between the two periods in terms of drought severity magnitudes, drought durations and annual occurrence times.