Petrography, chemistry and genesis of phosphorite concretions in the Eocene Umm Rijam Chert limestone Formation, Ma'an area, south Jordan   总被引：1，自引：0，他引：1  

Khalid Tarawneh  Khaled Moumani 《Journal of Asian Earth Sciences》2006,26(6):627-635

Phosphorite concretions are recorded for the first time within the lower part of the Umm Rijam Chert Limestone Formation (Eocene) in the Ma'an area, southern Jordan. The phosphorite concretions are typically hosted and encountered as individual layer in moderately lithified sediments of marl, chalk and chalky marl. The phosphorite concretions are present in thin layer (10–30 cm thick). They are localized on a hardground surface that formed as a result of cementation of soft ground by bioclastic materials. Light grey and brownish to black colors are encountered with isometric, ellipsoid, elongated, subangular to subrounded phosphorite concretions (up to 6 cm in length). Most of the phosphorite concretions preserve bioturbation structures; they also include fecal pellets of various sizes. The main biogenic components are fragments of macrofossils (bivalves) and microfossils (planktonic foraminifera) in different proportions. Petrographic examinations reveal that the phosphorite concretions are composed of cryptocrystalline apatite that characteristically appears in cross-polarized light almost as isotropic phosphate and minor anisotropic phosphate. Apatite and calcite are the main mineral constituents of the phosphorite concretions identified by XRD. The apatite is identified as francolite (carbonate-flour-apatite). Chemical analyses of the phosphorite concretions using X-ray florescence indicate that the P₂O₅ content ranges from 18.8 to 31.19%, whereas SEM–EDS analyses indicate that the phosphorus proportion is around 14% by volume. It could be argued that the phosphorite concretions were transported after being reworked, or were derived from carbonate and chalk pebbles that were later phosphatized and subjected to erosion, forming residual lag deposit along the hardground surface.  相似文献   

Active faulting and natural hazards in Armenia, eastern Turkey and northwestern Iran   总被引：1，自引：0，他引：1  

Arkady S. Karakhanian  Vladimir G. Trifonov  Herve Philip  Ara Avagyan  Khaled Hessami  Farshad Jamali  M. Salih Bayraktutan  H. Bagdassarian  S. Arakelian  V. Davtian  A. Adilkhanyan 《Tectonophysics》2004,380(3-4):189-219

Active fault zones of Armenia, SE Turkey and NW Iran present a diverse set of interrelated natural hazards. Three regional case studies in this cross-border zone are examined to show how earthquakes interact with other hazards to increase the risk of natural disaster. In northern Armenia, a combination of several natural and man-made phenomena (earthquakes, landslides and unstable dams with toxic wastes) along the Pambak-Sevan-Sunik fault (PSSF) zone lowers from 0.4 to 0.2–0.3g the maximum permissible level (MPL) of seismic hazard that may induce disastrous destruction and loss of life in the adjacent Vanadzor depression.

In the Ararat depression, a large active fault-bounded pull-apart basin at the junction of borders of Armenia, Turkey, Iran and Azerbaijan, an earthquake in 1840 was accompanied by an eruption of Ararat Volcano, lahars, landslides, floods, soil subsidence and liquefaction. The case study demonstrates that natural hazards that are secondary with respect to earthquakes may considerably increase the damage and the casualties and increase the risk associated with the seismic impact.

The North Tabriz–Gailatu fault system poses a high seismic hazard to the border areas of NW Iran, eastern Turkey, Nakhichevan (Azerbaijan) and southern Armenia. Right-lateral strike–slip motions along the North Tabriz fault have given rise to strong earthquakes, which threaten the city of Tabriz with its population of 1.2 million.

The examples illustrate how the concentration of natural hazards in active fault zones increases the risk associated with strong earthquakes in Armenia, eastern Turkey and NW Iran. This generally occurs across the junctions of international borders. Hence, the transboundary character of active faults requires transboundary cooperation in the study and mitigation of the natural risk.  相似文献   

Application of GPS in Traffic Management Systems     

Ardeshir Faghri  Khaled Hamad 《GPS Solutions》2002,5(3):52-60

Integrated Traffic Management Systems (ITMS) need reliable, accurate, and real-time data. Travel time, speed, and delay are three of the most important factors used in ITMS for monitoring, quantifying, and controlling congestion. GPS has recently become available for civil applications. Because it provides real-time spatial and time measurements, it has an increasing use in conducting different transportation studies. This article presents the application of GPS in collecting travel time, speed, and delay information of 64 major roads in the state of Delaware. A comparative statistical analysis was performed on data collected by GPS, with data collected simultaneously by the conventional method. The GPS data proved to be at least as accurate as the data collected by the conventional method, and it was 50% more efficient in terms of manpower. Moreover, the sample-size requirement was determined to maintain 95% confidence level throughout the controlled test. Benefiting from the Geographic Information System's dynamic segmentation tool, our travel time, delay, and speed information were integrated with other relevant traffic data. This was presented graphically on the Internet for public use. Statistical trend analysis for the data collected in 1997, 1998, 1999, and 2000 are also presented and applications on the overall ITMS are discussed. ? 2002 Wiley Periodicals, Inc.  相似文献   

Characterization of complex fluvial systems using remote sensing of spatial and temporal water level variations in the Amazon,Congo, and Brahmaputra Rivers   总被引：1，自引：0，他引：1  

Hahn Chul Jung  James Hamski  Michael Durand  Doug Alsdorf  Faisal Hossain  Hyongki Lee  A. K. M. Azad Hossain  Khaled Hasan  Abu Saleh Khan  A.K.M. Zeaul Hoque 《地球表面变化过程与地形》2010,35(3):294-304

The Surface Water and Ocean Topography (SWOT) satellite mission will provide global, space‐based estimates of water elevation, its temporal change, and its spatial slope in fluvial environments, as well as across lakes, reservoirs, wetlands, and floodplains. This paper illustrates the utility of existing remote sensing measurements of water temporal changes and spatial slope to characterize two complex fluvial environments. First, repeat‐pass interferometric SAR measurements from the Japanese Earth Resources Satellite are used to compare and contrast floodplain processes in the Amazon and Congo River basins. Measurements of temporal water level changes over the two areas reveal clearly different hydraulic processes at work. The Amazon is highly interconnected by floodplain channels, resulting in complex flow patterns. In contrast, the Congo does not show similar floodplain channels and the flow patterns are not well defined and have diffuse boundaries. During inundation, the Amazon floodplain often shows sharp hydraulic changes across floodplain channels. The Congo, however, does not show similar sharp changes during either infilling or evacuation. Second, Shuttle Radar Topography Mission measurements of water elevation are used to derive water slope over the braided Brahmaputra river system. In combination with in situ bathymetry measurements, water elevation and slope allow one to calculate discharge estimates within 2.3% accuracy. These two studies illustrate the utility of satellite‐based measurements of water elevation for characterizing complex fluvial environments, and highlight the potential of SWOT measurements for fluvial hydrology. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Temporal population dynamics of dinoflagellate Prorocentrum minimum in a semi-enclosed mariculture pond and its relationship to environmental factors and protozoan grazers     

许恒龙  MIN Gi-Sik  CHOI Joong-Ki  朱明壮  姜勇  AL-RASHEID Khaled A.S. 《中国海洋湖沼学报》2010,(1)

The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to ...  相似文献   

Molecular phylogeny of oligotrich genera Omegastrombidium and Novistrombidium (Protozoa, Ciliophora) for the systematical relationships within Family Strombidiidae     

张倩倩  伊珍珍  徐大鹏  龚骏  宋微波 《中国海洋湖沼学报》2010,28(4):769-777

The phylogeny of the oligotrich ciliates is currently a hot debate despite the availability of both morphological and molecular data. In the present paper, further small subunit rRNA (SS rRNA) genes were analyzed from the Genera Omegastrombidium and Novistrombidium, as well as from Strombidium, and combined with three new SS rRNA sequences from Strombidium basimorphum, S. sulcatum population QD-1, and Novistrombidium testaceum population GD. The phylogenetic positions of these organisms were inferred using Bayesian inference, Maximum Likelihood, and Maximum Parsimony methods. The main results are: (1) the SS rRNA gene sequence analyses match the recent findings about the molecular evolution of oligotrichs, indicating that the family Strombidiidae is paraphyletic; (2) the Genus Omegastrombidium is separated from the Genus Strombidium, as shown in recent cladistic analyses; (3) morphospecies in Genus Novistrombidium, based on similarity of somatic ciliature, are separated from each other in all topological trees, indicating that this genus could be a paraphyletic group; (4) the molecular data indicate a possibility of paraphyly for the genus Strombidium; and (5) the similarities of the SS rRNA gene of specimens identified as S. sulcatum and S. inclinatum are 99.8%–100%. However, present knowledge on the oligotrichs sensu stricto is still insufficient and further studies based on both molecular and other technologies are required.  相似文献   

Calcareous nannofossils biostratigraphy of the Late Campanian–Early Maastrichtian Age, Block 16, Jiza’-Qamar Basin, Eastern Yemen     

Khaled A. Al-Wosabi  Abdulwahab S. Alaug 《Arabian Journal of Geosciences》2013,6(9):3581-3594

One hundred and thirty nine samples have been studied from the Late Campanian–Early Maastrichtian of three deep wells drilled in Jiza’-Qamar Basin, Eastern Yemen to determine the calcareous nannofossil zones and the age of the sediments. Forty-seven calcareous nannofossil species were identified and four biozones were determined in the present study (CC21–CC24). These biozones are assigned to the Late Campanian–Early Maastrichtian ages. Most of the studied species in this work refer to tropical–subtropical environment. The Campanian–Maastrichtian Boundary was determined in Al-Fatk well based on the last occurrence of Eiffelithus eximus and the last occurrences of Uniplanarius sissinghii and Uniplanarius trifidus.  相似文献   

Bibliography on spatiotemporal databases     

Khaled K. Al-Taha  Richard T. Snodgrass  Michael D. Soo 《International journal of geographical information science》2013,27(1):95-103

Abstract

There now exist several microcomputer processing systems which incorporate algorithms and display techniques appropriate for the class of objects known as images. Zooming, histogram equalization, contrast stretching, ratioing, edge enhancement, and filtering are common options used in these systems. In the present discussion a system is proposed for the equivalent processing of general resolution elements (resells), instead of the homogeneous picture elements (pixels) which are found in image processing systems. The resel processing system requires a new, generalized, repertoire of processing algorithms and a high resolution display. A summary is provided of the facilities and procedures required, a computational metaphor using computer spreadsheets is described, and the applicability to censels (census data elements) and to medical data is suggested.  相似文献   

Magmatism at continental passive margins inferred from Ambient‐Noise Phase‐velocity in the Gulf of Aden          下载免费PDF全文

Félicie Korostelev  Sylvie Leroy  Derek Keir  Cornelis Weemstra  Lapo Boschi  Irene Molinari  Abdulhakim Ahmed  Graham W. Stuart  Frédérique Rolandone  Khaled Khanbari  Ali Al‐Lazki 《地学学报》2016,28(1):19-26

Non‐volcanic continental passive margins have traditionally been considered to be tectonically and magmatically inactive once continental breakup has occurred and seafloor spreading has commenced. We use ambient‐noise tomography to constrain Rayleigh‐wave phase‐velocity maps beneath the eastern Gulf of Aden (eastern Yemen and southern Oman). In the crust, we image low velocities beneath the Jiza‐Qamar (Yemen) and Ashawq‐Salalah (Oman) basins, likely caused by the presence of partial melt associated with magmatic plumbing systems beneath the rifted margin. Our results provide strong evidence that magma intrusion persists after breakup, modifying the composition and thermal structure of the continental margin. The coincidence between zones of crustal intrusion and steep gradients in lithospheric thinning, as well as with transform faults, suggests that magmatism post‐breakup may be driven by small‐scale convection and enhanced by edge‐driven flow at the juxtaposition of lithosphere of varying thickness and thermal age.  相似文献   

Changes in irrigation water consumption in the Nile Delta of Egypt assessed by remote sensing   总被引：1，自引：0，他引：1  

Mohammed A. El-Shirbeny  Magdy A. M. Alsersy  Nasser H. Saleh  Khaled A. Abu-Taleb 《Arabian Journal of Geosciences》2015,8(12):10509-10519

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