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31.
Abdulkader M. Abed Saja Abu Taha Tasneem H. Hiasat Abdalla Abu Hamad 《Arabian Journal of Geosciences》2016,9(11):587
A calcrete horizon, 3–10 m thick, is found exposed in northern Jordan in three localities, Rumman, Marsa’, and Wasfi At Tal forest (WTF). It is situated at the base of the dominantly limestone, Late Cenomanian Hummar Formation, separating it from the underlying marly Fuheis Formation. The calcrete horizon exhibits all the diagnostic features characteristic of calcrete, such as diagenetic pisoids; a mottled or clotted texture; circumgranular cracks around grains in a nodular texture; pendant or microstalactitic cement; meniscus cement; plant roots or rhizogenic structures, both longitudinal and transverse; exfoliation on boulder and cobbles; alagally laminated hard pans; and abundant dissolution of cracks and vugs. Consequently, it represents a subaerial erosional unconformity and type 1 sequence boundary (SB) that was not previously noticed. The Hummar Formation is considered as a third-order sequence with the SB at the base of the calcrete horizon, while the calcrete horizon itself forms the lowstand system tracts (LST). The transgressive systems tracts (TST) involve the lower two third of the Hummar Formation ending with peloidal grainstone representing the maximum flooding surface (MFSs). The rest of the formation is the falling highstand systems tracts (HST). The next SB is not seen due to a thick soil-covered gap. The calcrete horizon formed due to the formation of a paleohigh, in the study area, associated with the compression produced by the initial subduction of the Afro-Arabian Plate under the Eurasian Plate during the Late Cenomanian, slightly earlier than the previously known Turonian subduction and compression. 相似文献
32.
Mahfooz A. Hafez Magdy A. Atya Azza M. Hassan Motoyuki Sato Thomas Wonik Abeer K EI-Kenaw 《应用地球物理》2008,5(2):136-143
Ground penetrating radar, electromagnetic terrain conductivity, and electric tomography have proven to be effective tools if they are combined together to investigate archeological sites. We have conducted a geophysical survey at the Akhmim archaeological site, the main objective of our survey is to locate additional buried structures for further excavation. Geophysical data were acquired in the area using the GEM-300 multi-frequency terrain conductivity profiler, the SIR 2000 ground penetrating radar, and the Syscal R2 resistivity meter systems. The results of the integrated interpretation show a number of buried features and a strong linear zone about 1 m wide that coincides with the suspected trend of a buried wall. There appears to be two parallel ridges of strong reflections on either side, indicating two parallel walls extended East-West and a room is identified at the bottom left comer of the site. Moreover, the interpretation results of some selected GPR and dipoledipole resistivity profiles adjacent to the open-air museum suggest the existence of a second statue of Ramses Ⅱ to the right of the previously discovered statue which could still be buried in the sand. 相似文献
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34.
Nonlinear Dynamics and Bifurcations of a Supercavitating Vehicle 总被引：1，自引：0，他引：1
In this effort, a numerical study of the bifurcation behavior of a supercavitating vehicle is conducted. The vehicle model is nonsmooth; this is a result of the planing force acting on the vehicle. With a focus on dive-plane dynamics, bifurcations with respect to a quasi-static variation of the cavitation number are studied. The system is found to exhibit rich and complex nonlinear dynamics including nonsmooth bifurcations such as the grazing bifurcation; smooth bifurcations such as Hopf bifurcations, cyclic fold bifurcations, and period-doubling bifurcations; and aperiodic behaviors such as transient chaotic motions and chaotic crises. The tailslap phenomenon of the supercavitating vehicle is identified as the consequence of a Hopf bifurcation followed by a grazing event. It is shown that the occurrences of these bifurcations can be delayed or triggered earlier by using dynamic linear feedback control laws employing washout filters. 相似文献
35.
The stream sediments of Wadi El Reddah(North Eastern Desert,Egypt)are geochemically and mineralogically investigated.Their content of radioactive and other heavy minerals is mainly represented by thorite,uranothorite,zircon,monazite,xenotime,columbite,fergusonite,and unknown rare earth elements(REEs)bearing minerals as well as cassiterite.Special emphasis on REE content of thorite,uranothorite,zircon and xenotime has been done to correlate them with the increase of uranium contents in these sediments.The key evidence for the presence lowtemperature alteration processes includes the presence of some zircon crystals as remnants after complete dissolution of the overgrowth zircon in severe acidic environment,the sulphur content,biogenic minerals,occurrence of unusual minerals as cassiterite pore filling in zircon,variation in the REEs content from the surrounding granites to the stream sediments and the abundance of monazite in the surrounding granites.Most minerals are partially and/or completely altered,which indicated by the pseudomorphism of zircon by xenotime,thorite,and uranothorite. 相似文献
36.
Agi Augustine Junin Radzuan Abbas Azza Gbadamosi Afeez Azli Nur Bashirah 《Natural Resources Research》2020,29(2):1427-1446
Natural Resources Research - Nano-particles can localize at oil–water (O/W) interface, reduce residual oil saturation, increase the viscosity of brine and decrease the viscosity of crude oil... 相似文献
37.
Bayan Muhie Hussien Abed Salih Fayyadh Jassim Mohmmed Hammed Mohammed Affan Al Hamdani 《Arabian Journal of Geosciences》2013,6(3):783-799
The study of hydrochemical models and probable pollution in Euphrates River from Qaem–Al-Falluja was performed through regime observation in ten water points. The hydrochemical properties of Euphrates River waters are determined by using the analysis results of 21 physico-chemical variables during the water year (2008). The interpretation of the hydrochemical phenomena is achieved in accordance with the statistical results of Polynomial Regression Statistic, calculating the coefficient of variation among the physico-chemical components of the water terminating by 14 models. The results of monitoring during the water year 2008 indicate a pollution case by SO4 and Cd in Ramadi and downstream stations; TDS, Mg, Na, Cl, Mn, and CO2 in Ramadi station; TDS, Ca, Na, Cl, and Fe in Baghdadi station; and Ca and H T in Qaem station and Mg in Obaydi station. The research suggests the best locations for hydrochemical monitoring as continuous hydrologic stations used for the long-term monitoring. These stations are in Qaem city as inlet location and Al-Baghdadi and Ramadi cities terminating in Falluja city as outlet location. Furthermore, daily record system is recommended for the other stations in each city to complete the regime observation of Euphrates water type. From the configuration approach of hydrochemical models with the pollution phenomena, there are potential point sources of pollution such as municipal effluent pipes and reused water from mining process for building materials in the first sector of river, which extends between Qaem and Haditha dam. Also groundwater seepages and springs discharge of mineralized water mixed with sewage water from cities act as potential point sources of pollution on the river water in the second sector extended between Haditha and Ramadi scheme. The third sector of the river is affected by all reasons in the first and second sectors as well as the effectiveness of agricultural activities throughout drainage canals and irrigation projects extended between Ramadi and Falluja cities. 相似文献
38.
Mineralogy, geochemistry, and reserve estimation of the Euphrates limestone for Portland cement industry at Al-Najaf area, South Iraq 总被引：1，自引：1，他引：0
Mautaz Al-Dabbas Salih Muhammad Awadh Ayad Abed Zaid 《Arabian Journal of Geosciences》2013,6(2):491-503
This study deals with the mineralogical and geochemistry of the Euphrates Formation (Lower Miocene) in Bahr Al-Najaf area in order to assess the lithofacies of the Euphrates Formation for Portland cement manufacturing. Petrographic and mineralogical studies were carried out on 210 core samples, collected from 21 boreholes, and showed that calcite is the dominant mineral with few amounts of quartz, gypsum, feldspar, and a rare amount of dolomite. Clay mineral suites (palygorskite, kaolinite, montmorillonite, and illite) formed about 5% from the total mineral composition. Palygorskite precipitated directly in alkali shallow water rich with Si and Mg ions. Chemical weathering of feldspar under acidic conditions participated in formation of Kaolinite. Geochemistry showed that there is no high variation in chemical constituents with depth, and the average of CaO (51.5), MgO (0.83), SO3 (0.54), SiO2 (4.3), Fe2O3 (0.45), Al2O3 (0.93), L.O.I (40.7), Na2O3 (0.08), K2O (0.14), and Cl- (0.1) qualified the lithofacies of Euphrates Formation to be raw materials suitable for manufacturing the Portland cement. Triangle Block method is applied to estimate the reserve on square area (2?×?2 km2) which is computed to be 63 million tons of medium-tough limestone as potential probable reserve. 相似文献