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Sample records for western desert egypt

  1. Petroleum potential of Western Desert of Egypt

    SciTech Connect

    Wood, D.S.

    1984-09-01

    The Western Desert of Egypt, despite many discouragements, has major potential as a petroleum province. Approximately 150 exploratory wells have discovered nine commercial oil and gas fields, with flows of oil or gas recorded from an additional 21 wells. All discoveries have been in marine inner shelf sandstones and carbonates that range from Aptian to Turonian in age. Potential reservoir rocks are known in Paleozoic to Tertiary sedimentary rocks. Mature source rocks have been recognized in the Devonian and in Jurassic to Upper Cretaceous strata. Despite these favorable factors, in-place reserves of only 800 million bbl of oil and condensate, and up to 1185 bcf of natural gas have been found. Almost all exploration has been limited to the drilling of relatively small onshore structures and no giant fields have been found. New investigations utilizing a broad regional tectonic framework provide a means both of recognizing the more prospective provinces of the Western Desert and for understanding the structural evolution in terms of the timing of growth folding and growth faulting. Particular attention should be given to testing the lower part of the Cretaceous and Jurassic. The Paleozoic section also warrants further attention as demonstrated by a review of drilling results and by indications from gravity data. The new investigations indicate a considerable potential within the Western Desert for discovery of small to moderate-size accumulations of oil and gas. More exploration should test these features, which although high-risk leads, may contain giant fields.

  2. Groundwater sapping processes, Western Desert, Egypt.

    SciTech Connect

    Luo, W.; Arvidson, R.E.; Sultan, M.; Becker, R.; Crombie, M.K.; Sturchio, N.; El Alfy, Z.; Environmental Research; Washington Univ.; Egyptian Geological Survey and Mining Authority

    1997-01-01

    Depressions of the Western Desert of Egypt (specifically, Kharga, Farafra, and Kurkur regions) are mainly occupied by shales that are impermeable, but easily erodible by rainfall and runoff, whereas the surrounding plateaus are composed of limestones that are permeable and more resistant to fluvial erosion under semiarid to arid conditions. Scallop-shaped escarpment edges and stubby-looking channels that cut into the plateau units are suggestive of slumping of limestones by ground-water sapping at the limestone-shale interfaces, removal of slump blocks by weathering and fluvial erosion, and consequent scarp retreat. Spring-derived tufa deposits found near the limestone escarpments provide additional evidence for possible ground-water sapping during previous wet periods. A computer simulation model was developed to quantify the ground-water sapping processes, using a cellular automata algorithm with coupled surface runoff and ground-water flow for a permeable, resistant layer over an impermeable, friable unit. Erosion, deposition, slumping, and generation of spring-derived tufas were parametrically modeled. Simulations using geologically reasonable parameters demonstrate that relatively rapid erosion of the shales by surface runoff, ground-water sapping, and slumping of the limestones, and detailed control by hydraulic conductivity inhomogeneities associated with structures explain the depressions, escarpments, and associated landforms and deposits. Using episodic wet pulses, keyed by {delta}{sup 18}O deep-sea core record, the model produced tufa ages that are statistically consistent with the observed U/Th tufa ages. This result supports the hypothesis that northeastern African wet periods occurred during interglacial maxima. The {delta}{sup 18}O-forced model also replicates the decrease in fluvial and sapping activity over the past million years, as northeastern Africa became hyperarid. The model thus provides a promising predictive tool for studying long

  3. The corrosive well waters of Egypt's western desert

    USGS Publications Warehouse

    Clarke, Frank Eldridge

    1979-01-01

    The discovery that ground waters of Egypt's Western Desert are highly corrosive is lost in antiquity. Inhabitants of the oases have been aware of the troublesome property for many decades and early investigators mention it in their reports concerning the area. Introduction of modern well-drilling techniques and replacements of native wood casing with steel during the 20th century increased corrosion problems and, in what is called the New Valley Project, led to an intense search for causes and corrective treatments. This revealed that extreme corrosiveness results from combined effects of relatively acidic waters with significant concentrations of destructive sulfide ion; unfavorable ratios of sulfate and chloride to less aggressive ions; mineral equilibria and electrode potential which hinder formation of protective films; relative high chemical reaction rates because of abnormal temperatures, and high surface velocities related to well design. There is general agreement among investigators that conventional corrosion control methods such as coating metal surfaces, chemical treatment of the water, and electrolytic protection with impressed current and sacrificial electrodes are ineffective or impracticable for wells in the Western Desert's New Valley. Thus, control must be sought through the use of materials more resistant to corrosion than plain carbon steel wherever well screens and casings are necessary. Of the alternatives considered, stainless steel appears to. be the most promising where high strength and long-term services are required and the alloy's relatively high cost is acceptable. Epoxy resin-bonded fiberglass and wood appear to be practicable, relatively inexpensive alternatives for installations which do. not exceed their strength limitations. Other materials such as high strength aluminum and Monel Metal have shown sufficient promise to. merit their consideration in particular locations and uses. The limited experience with pumping in these desert

  4. Ground-water sapping processes, Western Desert, Egypt

    SciTech Connect

    Luo, W.; Arvidson, R.E.; Sultan, M.; Becker, R.; Crombie, M.K.; Sturchio, N.; Alfy, Z.E.

    1997-01-01

    Depressions of the Western Desert of Egypt (specifically, Kharga, Farafra, and Kurkur regions) are mainly occupied by shales that are impermeable, but easily erodible by rainfall and runoff, whereas the surrounding plateaus are composed of limestones that are permeable and more resistant to fluvial erosion under semiarid to arid conditions. A computer simulation model was developed to quantify the ground-water sapping processes, using a cellular automata algorithm with coupled surface runoff and ground-water flow for a permeable, resistant layer over an impermeable, friable unit. Erosion, deposition, slumping, and generation of spring-derived tufas were parametrically modeled. Simulations using geologically reasonable parameters demonstrate that relatively rapid erosion of the shales by surface runoff, ground-water sapping, and slumping of the limestones, and detailed control by hydraulic conductivity inhomogeneities associated with structures explain the depressions, escarpments, and associated landforms and deposits. Using episodic wet pulses, keyed by {delta}{sup 18}O deep-sea core record, the model produced tufa ages that are statistically consistent with the observed U/Th tufa ages. This result supports the hypothesis that northeastern African wet periods occurred during interglacial maxima. This {delta}{sup 18}O-forced model also replicates the decrease in fluvial and sapping activity over the past million years. 65 refs., 21 figs., 2 tabs.

  5. Palynology of Albian-Cenomanian strata in Mersa Matruh well, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Sultan, Ismail Z.

    Plant microfossils have been recovered from the Albian and lower Cenomanian strata encountered in Mersa Matruh well No. 1, drilled in the northern part of the Western Desert of Egypt. The microflora includes 56 miospore species belonging to 35 genera; most of them are derived from pteridophyte, gymnosperm and angiosperm vegetations. Differences in miospore assemblages of the Albian and Lower Cenomanian are described. Correlation with coeval palynofloral assemblages in West Africa and South and North America reveals that the Mersa Matruh area, Egypt belongs to the mid-Cretaceous African-South American phytogeoprovince.

  6. Volatiles in the Desert: Subtle Remote-sensing Signatures of the Dakhleh Oasis Catastrophic Event, Western Desert, Egypt

    NASA Technical Reports Server (NTRS)

    Haldemann, A. F. C.; Kleindienst, M. R.; Churcher, C. S.; Smith, J. R.; Schwarcz, H. P.; Osinski, G.

    2005-01-01

    Over the past decade members of the Dakhleh Oasis Project have studied enigmatic signatures in the Pleistocene geologic record of portions of the Dakhleh oasis and palaeo-oasis in Egypt's Western Desert [1,2]. In particular, Si-Ca-Al rich glass melt (Dakhleh Glass, Fig. 1) points to a catastrophic event between c.100,000-200,000 years ago [3] in this well-studied African savannah and freshwater lake Middle Stone Age environment [4,5].

  7. Geological heritage of the Bahariya and Farafra oases, the central Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Plyusnina, Ekaterina E.; Sallam, Emad S.; Ruban, Dmitry A.

    2016-04-01

    Archaeological and cultural heritage of Egypt is world-known, but its geological heritage is yet to be revealed. Investigations in the central Western Desert of Egypt permitted finding a lot of unique features that can be assigned to this heritage. In the Bahariya Oasis, 10 geological heritage types are established, namely stratigraphical, paleontological, sedimentary, igneous, mineralogical, economical, paleogeographical, geomorphological, hydrological and hydrogeological, and pedological types. In the Farafra Oasis and vicinities, only geomorphological and hydrological and hydrogeological types are found. On the area between these oases, sedimentary, mineralogical, paleogeographical, and geomorphological features are established. Chalk and nummulitic limestones, invertebrate and dinosaur localities, paleoreefs and paleokarst, iron ore deposit, and peculiar landforms occur on the study territory. Taken together, these features constitute a highly diverse geological heritage that can be judged global (even if the rank of individual objects is often relatively low). This heritage is well suitable for the purpose of geotourism; for instance, thematic excursions explaining the geological evolution during the last 100 Ma are possible. Participants of such excursions can also see different facies. A geopark in the central Western Desert of Egypt would facilitate geoconservation and geotourism activities.

  8. Application of LANDSAT satellite imagery for iron ore prospecting in the Western Desert of Egypt

    NASA Technical Reports Server (NTRS)

    Elshazly, E. M.; Abdelhady, M. A.; Elghawaby, M. A.; Khawasik, S. M.

    1977-01-01

    Prospecting for iron ore occurrences was conducted by the Remote Sensing Center in Bahariya Oasis-El Faiyum area covering some 100,000 km squared in the Western Desert of Egypt. LANDSAT-1 satellite images were utilized as the main tool in the regional prospecting of the iron ores. The delineation of the geological units and geological structure through the interpretation of the images corroborated by field observations and structural analysis led to the discovery of new iron ore occurrences in the area of investigation.

  9. Morphologic characteristics and migration rate assessment of barchan dunes in the Southeastern Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Hamdan, M. A.; Refaat, A. A.; Abdel Wahed, M.

    2016-03-01

    This work explores the morphologic characteristics of aeolian dune sand in the southeastern part of Western Desert of Egypt. It aims to assess the movement of barchan dunes and evaluate their environmental influence on the Toshka Project. Morphometric investigation of barchan dunes in the Toshka area revealed that most barchans have high length/width (a/c) ratios (fat to pudgy), while one-fifth of the studied barchans have lower a/c ratios and so appear normal in their morphologic forms. Statistical analysis of the main parameters of barchan dunes in Toshka and other desert regions in the Kharga (Egypt), Kuwait, Southern Morocco, California and Southern Peru demonstrates that barchans of the Toshka area are distinctive in their appearance. They are characterized by distinct aspect with higher values of length and width and greater growth in height. The high-energy wind environment in addition to the large amount of drifting sand are principal factors responsible for the unique shape of Toshka barchans. The migration rate of barchan dunes in four chosen test locations, within the central and western Toshka area, ranges from about 3 to 10.82 m/year. The calculated average migration rate of these dunes is about 6 m/year in a SSW direction. Sand encroachment is more extensive in the central and western parts of the investigated Toshka area. Risk evaluation of sand dune movements in the southeastern part of the Western Desert points to medium to high sand encroachment risk values. These may represent serious hazards to the newly-established Toshka Project, threatening roads, as well as cultivated lands in the area.

  10. Mesozoic rift basins in western desert of Egypt, their southern extension and impact on future exploration

    SciTech Connect

    Taha, M.A. )

    1988-08-01

    Rift basins are a primary target of exploration in east, central, and west Africa. These intracratonic rift basins range in age from the Triassic to the Neogene and are filled with lagoonal-lacustrine sand-shale sequences. Several rift basins may be present in the Western Desert of Egypt. In the northeastern African platform, the Mesozoic Tethyan strand lines were previously interpreted to have limited southern extension onto the continent. This concept, based upon a relatively limited amount of subsurface data, has directed and focused the exploration for oil and gas to the northernmost 120 km of the Western Desert of Egypt. Recent well and geophysical data indicate a southerly extension of mesozoic rift basins several hundred kilometers inland from the Mediterranean Sea. Shushan/Faghur and Abu Gharadig/Bahrein basins may represent subparallel Mesozoic basins, trending northeast-southwest. Marine Oxfordian-Kimmeridgian sediments were recently reported from wells drilled approximately 500 km south of the present-day Mediterranean shoreline. The link of these basins with the Sirte basin to the southwest in Libya is not well understood. Exploration is needed to evaluate the hydrocarbon potential of such basins.

  11. Pitted and fluted rocks in the Western Desert of Egypt - Viking comparisons

    NASA Technical Reports Server (NTRS)

    Mccauley, J. F.; Breed, C. S.; Grolier, M. J.; El-Baz, F.; Whitney, M. I.; Ward, A. W.

    1979-01-01

    The Western Desert of Egypt is one of the most arid regions on earth and is probably the closest terrestrial analog to the surface of Mars. An expedition to the area in 1978 revealed an abundance of quartzite and basalt rocks that have been pitted and fluted by wind erosion and deflation of the desert surface. These pitted rocks are internally homogeneous, show no internal holes or vesicles, and are considered an important but neglected type of ventifact. They bear a striking resemblance to the pitted and fluted rocks seen by the Viking Landers, rocks that have generally been interpreted as vesicular basalts only slightly modified by wind erosion. Wind tunnel studies of the air flow over and around nonstreamlined hand specimens from the Western Desert show that windward abrasion coupled with negative flow, secondary flow, and vorticity in a unidirectional wind can explain the complex arrays of pits and flutes. These field and laboratory observations suggest that the pitted rocks at the Viking Lander sites are also ventifacts, and thus the Martian surface may be far more wind eroded than previously thought.

  12. A socio-ecological investigation of options to manage groundwater degradation in the Western Desert, Egypt.

    PubMed

    King, Caroline; Salem, Boshra

    2012-07-01

    Under increasing water scarcity, collective groundwater management is a global concern. This article presents an interdisciplinary analysis of this challenge drawing on a survey including 50 large and small farms and gardens in a village in an agricultural land reclamation area on the edge of the Western Desert of Egypt. Findings revealed that smallholders rely on a practice of shallow groundwater use, through which drainage water from adjacent irrigation areas is effectively recycled within the surface aquifer. Expanding agroindustrial activities in the surrounding area are socio-economically important, but by mining non-renewable water in the surrounding area, they set in motion a degradation process with social and ecological consequences for all users in the multi-layered aquifer system. Based on the findings of our investigation, we identify opportunities for local authorities to more systematically connect available environmental information sources and common pool resource management precedents, to counterbalance the degradation threat. PMID:22569842

  13. Inverted topography in the southeastern part of the Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Zaki, Abdallah S.; Giegengack, Robert

    2016-09-01

    We present here a series of surficial geologic maps of 22,000 km2 of the southeastern part of the Western Desert of Egypt showing 3084 bodies of wadi-floor sediment that have been inverted by erosion to form sinuous ridges capped by alluvial gravel, here described as "inverted wadis". These features represent fragments of one or more ancient drainage systems that developed at times when rainfall, and hence overland flow, was greater than it is today in this hyperarid region. While some of the inverted wadis were tributaries to a through-flowing river that followed the course of the modern Nile, others converge on what appear to have been internal closed basins west of the Nile. Several components of this ancient drainage system have yielded artifacts assigned to an Acheulian lithic tradition, but there is not yet enough stratigraphic information available to enable us to relate this ancient drainage system to any of the proposed scenarios of Nile evolution.

  14. Evidence for a ˜ 200 100 ka meteorite impact in the Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Osinski, Gordon R.; Schwarcz, Henry P.; Smith, Jennifer R.; Kleindienst, Maxine R.; Haldemann, Albert F. C.; Churcher, Charles S.

    2007-01-01

    In this study, we present evidence, in the form of unusual silicate glasses, for a meteorite impact event ˜ 200-100 ka in the Dakhleh Oasis, Western Desert, Egypt. These glasses, known locally as Dakhleh Glass, were derived from the shock melting of a series of unconsolidated sediments underlain by interbedded carbonates, sandstones and phosphate-rich lithologies. Hypervelocity impact in to a volatile-rich target resulted in the production of impact glasses with CaO and Al 2O 3 contents of up to ˜ 25 and 18 wt.%, respectively. Other notable properties include the presence of globules of immiscible calcite and pyrrhotite melt phases, shattered quartz grains, and fragments of silicified plant matter. Dating of geoarchaeological artefacts associated with the Dakhleh Glass support preliminary 40Ar/ 39Ar data, indicating a ˜ 200-100 ka age for the impact event. Geoarchaeological evidence indicates that archaic Homo sapiens and early modern humans continually inhabited this region of the Western Desert during this period. While it is unclear at present whether the Dakhleh Glass was formed during a cratering event or a large aerial burst, the effect on the environment and inhabitants of Dakhleh would have been catastrophic.

  15. Age and isotopic constraints on pleistocene pluvial episodes in the Western Desert, Egypt.

    SciTech Connect

    Crombie, M. K.; Arvidson, R. E.; Sturchio, N. C.; El Alfy, Z.; Abu Zeid, K.; Environmental Research; Washington Univ.; Egyptian Geological Survey and Mining Authority

    1997-01-01

    North Africa has undergone drastic climatic changes over the past several hundred thousand years. The timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. The youngest and best dated travertines (70-160 ka) are found in Wadi Kurkur and include spring and lacustrine units exposed as 2 to 3 m high terraces. Travertines having an age of approximately 191-220 ka are exposed by differential erosion as linear mounds produced by spring systems over fracture zones in ancient wadis. The oldest travertines, having ages >260 ka, are extensive, cap limestone units above the oasis, and were deposited in paludal and lacustrine environments. Oxygen isotope ratios were measured for the wadi travertines ({delta}{sup 18}O values ranging from 16.7 to 19.1{per_thousand} SMOW) and for spring mound travertines (18.5-20.5{per_thousand}). Equilibrium oxygen isotope fractionation calculations indicate that the Kurkur travertines were deposited from waters having {delta}{sup 18}O values similar to ancient Western Desert groundwaters ({approx} -11{per_thousand}). The ages of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Rainfall producing these groundwaters (and travertines) was significantly fractionated during atmospheric transport, in contrast to modern meteoric waters (-2.09{per_thousand}), implying a distant source for the pluvial waters. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch insolation cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during interglacial time periods.

  16. A new Priabonian Chondrichthyans assemblage from the Western desert, Egypt: Correlation with the Fayum oasis

    NASA Astrophysics Data System (ADS)

    Adnet, S.; Cappetta, H.; Elnahas, S.; Strougo, A.

    2011-08-01

    While the Middle/Late Eocene marine vertebrates in Egypt have been largely reported around the Fayum oasis, few reports were made elsewhere. Here we report a new fossil site (Km55) located near the Bahariya Oasis in the Western desert of Egypt. This fossiliferous outcrop has yielded abundant fossil material of invertebrates dated to the Middle/Late Eocene and some chondrichthyan remains that testify of a Priabonian age (MK11). More than twenty Selachian taxa were recovered in one level, including " Cretolamna " twiggsensis, Misrichthys stromeri, Odontorhytis pappenheimi, ? Jacquhermania attiai, and the fauna is quite similar to some recovered from the Fayum area. However, this new association is clearly distinctive of an open marine environment during the extreme Late Eocene while the contemporaneous fossil sites farther east are deposited in shallower (e.g. Wadi Hitan) or continental environments (e.g. BQ-2). This suggests an E-W diachronous change in relative sea level on the Egyptian coastal shelf during the Late Eocene period, with a general deepening along strike to the West.

  17. Optimal well locations using genetic algorithm for Tushki Project, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Khalaf, S.; Gad, M. I.

    2014-10-01

    Groundwater depletion is one of the most important problems threaten the national projects in Egypt. The optimal distribution of well locations and pumping rates mitigate this problem. In this paper, a trial to mitigate this problem in Tushki National Project, south western desert, Egypt was carried out via delineating the optimal well locations and optimal pumping rates. The methodology of combination between simulation and optimization techniques was applied. A linked simulation-optimization model for obtaining the optimum management of groundwater flow is used in this research. MODFLOW packages are used to simulate the groundwater flow system. This model is integrated with an optimization model OLGA (Optimal well Location using Genetic Algorithm technique) which is based on the genetic algorithm (GA). Two management cases were considered by running the model in Abu Simbel-Tushki area with adopted steady and transit calibrated parameters. The first case (fixed well location) is found that the optimum value of the objective function (maximum pumping rate). In the second case (flexible well location with the moving well option) locations of wells are to be decided by the OLGA model itself within a user defined region of the model grid until the optimal location is reached. Also, the prediction of the future changes in both head and flow were made in steady and transient states.

  18. Remote sensing and geophysical investigations of Moghra Lake in the Qattara Depression, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Khan, Shuhab D.; Fathy, Mohamed S.; Abdelazeem, Maha

    2014-02-01

    The Western Desert covers two-thirds of the land area of Egypt and occupies one of the driest regions of the Sahara. Seven depressions within the desert - Siwa, Qattara, Fayum, Bahariya, Farafra, Dakhla, and Kharga - may represent parts of old drainage systems with deflation, extensive erosion, and possibly, some tectonic activity. Oases with freshwater exist in these depressions. Geological and geophysical investigations in the Qattara Depression indicate the presence of buried fluvial channels with southeast to northwest flow directions from the highland areas. The origin of these fluvial systems, as well as the origin of the depressions themselves, is still unresolved, and many ideas have been suggested. Moghra Lake at the northeastern tip of the Qattara basin may be a remnant of a larger paleolake, including the mouth of a paleo-river. We present here the results of our recent work in this area using ALOS PALSAR radar remote sensing data, which indicated the presence of buried channels that may have fed the larger Moghra paleolake. Ground penetrating radar (GPR) data along 2D profiles were acquired; the migrated GPR sections identified a major paleochannel with numerous minor channels at its margins. GPR interpretations are verified by field observations, trenching, and stratigraphic information from outcrop data. Potential field analyses identify possible aquifers that are controlled by regional structures. Density contrasts within the sedimentary units, physical boundaries of uplifted basement blocks and depths to causative sources were also identified. This work contributes to the reconstruction of paleodrainage of this region and helps in understanding processes involved in the formation of the Qattara Depression.

  19. 1st paleomagnetic investigation of Nubia Sandstone at Kalabsha, south Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Mostafa, R.; Khashaba, A.; El-Hemaly, I. A.; Takla, E. M.; Abdel Aal, E.; Odah, H.

    2016-06-01

    Two profiles have been sampled from the Nubia Sandstone at Aswan, south Western Desert: the 1st profile has been taken from Abu Aggag Formation and the 2nd one was from Sabaya Formation (23.25 °N, 32.75 °E). 136 oriented cores (from 9 sites) have been sampled. Abu Aggag Formation is of Late Cretaceous (Turonian) and Sabaya Formation is of early Cretaceous (Albian-Cenomanian). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment. It has been found that hematite is the main magnetic mineral in both formations. Four profile sections from Abu Aggag Formation, yielded a magnetic component with D = 352.7°, I = 36.6° with α95 = 5.2° and the corresponding pole lies at Lat. = 82.8 °N and Long. = 283.1 °E. Five profile sections from Sabaya Formation, yielded a magnetic component with D = 348.6°, I = 33.3° with α95 = 5.8° and the corresponding pole lies at Lat. = 78.3 °N and Long. = 280.4 °E. The obtained paleopole for the two formations lies at Lat. = 80.5 °N and Long. = 281.7 °E. The obtaind magnetic components are considered primary and the corresponding paleopole reflects the age of Nubia Sandstone when compared with the previously obtained Cretaceous poles for Egypt.

  20. Paleomagnetism of Abu Aggag and Sabaya Formations at Kalabsha, South Western Desert of Egypt.

    NASA Astrophysics Data System (ADS)

    Mostafa, Reem; Khashaba, Ahmed; El-Hemaly, Ibrahim; Takla, Emad; Abdel Aal, Mohamed; Odah, Hatem

    2015-04-01

    Two profiles have been sampled from the Nubia Sandstone at Aswan, south Western Desert: The 1st profile has been taken from Abu Aggag Formation and the 2nd one was from Sabaya Formation (23.25 oN, 32.75 oE). 136 oriented cores (from 9 sites) have been sampled. Abu Aggag Formation is of Late Cretaceous (Turonian) and Sabaya Formation is of Early Cretaceous (Albian-Cenomanian). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment. It has been found that hematite is the main magnetic mineral in both formations. Four profile sections (normal polarity) from Abu Aggag Formation, yielded a magnetic component with D = 352.7°, I = 36.6° with 95 = 5.2° and the corresponding pole lies at lat. = 82.8 °N and long. = 283.1 °E. Five profile sections (normal polarity) from Sabaya Formation, yielded a magnetic component with D = 348.6°, I = 33.3° with 95 = 5.8° and the corresponding pole lies at lat. = 78.3 °N and long. = 280.4 °E. The obtained paleopole for the two formations lies at lat. = 80.5 °N and long. = 281.7 °E. The obtaind components are considered primary and the corresponding paleopole reflects the age of Nubia Sandstone when compared with the previously obtained Cretaceous poles for Egypt.

  1. Habitat of oil in Abu Gharadig and Faiyum basins, Western Desert, Egypt

    SciTech Connect

    Awad, G.M.

    1984-05-01

    The Abu Gharadig and Faiyum basins are areas which have some of the greatest hydrocarbon potential in the Western Desert of Egypt. Several extensive cycles of marine transgression and regression occurred in these territories through geologic time. The depositional cycles combined with at least 3 tectonic cycles--the Hercynian orogeny at the end of the Paleozoic, from Late Jurassic to early Tertiary, and from Late Cretaceous to middle Tertiary--resulted in a highly deformed, thick sedimentary sequence. This organic-rich Jurassic-Upper Cretaceous-lower Tertiary sequence in large areas of these basins was subjected to enough heat and depth to generate hydrocarbons. It is evident from recent discoveries that these source rocks generated large amounts of highquality oil and gas. Exploration efforts should be concentrated on deep structures close to the main depocenters and inside or very close to the 150/sup 0/F geothermal contour. Contemporaneous structures on the northern rims of the basins should have high potential, resulting from migration of hydrocarbons from the south across major faults. The Jurassic in the northeastern part of the Abu Gharadig basin may provide good hydrocarbon potential. The lower Tertiary sequence present in the troughs also may have large amounts of oil entrapped in situ or resulting in shortdistance migration to the northern structures or to the Late Cretaceous-early Tertiary Syrian arc traps.

  2. Habitat of oil in Abu Gharadig and Faiyum basins, Western Desert, Egypt

    SciTech Connect

    Awad, G.M.

    1984-05-01

    The Abu Gharadig and Faiyum basins are areas which have some of the greatest hydrocarbon potential in the Western Desert of Egypt. Several extensive cycles of marine transgression and regression occurred in these territories through geologic time. The depositional cycles combined with at least 3 tectonic cycles - (1) the Hercynian orogeny at the end of the Paleozoic, (2) from Late Jurassic to early Tertiary, and (3) from Late Cretaceous to middle Tertiary - resulted in a highly deformed, thick sedimentary sequence. This organic-rich Jurassic-Upper Cretaceous-lower Tertiary sequence in large areas of these basins was subjected to enough heat and depth to generate hydrocarbons. The Abu Gharadig and Faiyum basins are separated structurally by a major ridge. Both basins are bounded on the north by another major ridge associated with Cretaceous and Tertiary faulting. A major platform with tin sedimentary cover forms the southern boundary. The hydrocarbon potential exists in cyclic sequences of sandstone, shale, and carbonate, having moderate porosities and permeabilities. An important hydrologic phenomenon prevails in major parts of the basins; fresh water has flushed the early Cenomanian and older reservoirs. Exploration efforts should be concentrated on deep structures close to the main depocenters and inside or very close to the main depocenter and inside or very close to the 150/sup 0/F (65/sup 0/C) geothermal contour.

  3. The economic potential of El-Gedida glauconite deposits, El-Bahariya Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El-Habaak, Galal; Askalany, Mohamed; Faraghaly, Mohamed; Abdel-Hakeem, Mahmoud

    2016-08-01

    The mining work at El-Gedida iron mine, El-Bahariya Oasis, in the Western Desert of Egypt extracts commercial iron ore deposits without attention paid to the large glauconite deposits overlying these iron ore deposits. For this reason, the present paper aims at evaluating and attracting the attention to these glauconite deposits as alternative potassium fertilizers. The study was achieved by investigating mineralogical, physical and chemical properties of the green deposits. Mineralogical and physical properties involved the determination of glauconite pellets content in different grain size fractions relative to impurities and the analysis of the percentage of clay matrix and grain size distribution. Different pre-treatment strategies and methods including comminution, sieving, magnetic separation, and X-ray diffraction were used for investigating those mineralogical and physical properties. On the other hand, chemical analyses included potassium content, heavy metal concentrations, and pH and salinity measurements. The major elements and trace elements were measured using ICP-OES and the pH was measured using a pH conductometer. Moreover, this study investigated the nature of grain boundaries and the effect of sieving on glauconite beneficiation. Results of this study suggest that El-Gedida glauconite deposits are mineralogically, physically and chemically suitable for exploitation and can be beneficiated for use as an alternative potassium fertilizer.

  4. Authigenic dolomite cementation in the Upper Cretaceous Phosphate Formation, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Rifai, Rifai I.; Shaaban, Mohamad N.

    2007-12-01

    The Upper Cretaceous Phosphate Formation in the Western Desert of Egypt displays a characteristic facies association that includes marine phosphorites interbedded with black shales and glauconitic sandstones. The upper part of the formation is characterized by the presence of thin phosphatic beds, which are filled-extensively-with disordered and non stoichiometric (mean MgCO 3 = 41.4 ± 0.34 mol%) authigenic dolomite cement. SEM and the back scattered images of these coarse crystalline dolomite cements reveal that they display planar euhedral crystal boundaries, polymodal crystal size distribution and variable inclusion pattern. The relatively low and wide ranged δ18O (- 0.87 to - 4.15‰ VPDB) values of the dolomite cements coupled with their depleted Sr (mean = 187 ± 26 ppm) and high iron and manganese values (mean = 6851 ± 554 ppm and 11599 ± 229 ppm respectively) invoke that they were formed from mixed hypo-saline fluids within a mixing marine-meteoric zone probably during a low stand period at the vicinity of the Maastrichtian/Early Tertiary unconformity. Meanwhile, their negative δ13C (- 1.31 to - 3.56‰ VPDB) values argue for a possible involvement of isotopically light carbon, derived from degradation of organic matter, during their precipitation.

  5. Reconstructing Quaternary pluvial episodes and paleohydrology using travertines from Egypt's Western Desert

    NASA Astrophysics Data System (ADS)

    Jimenez, G.; Crossey, L. J.; Karlstrom, K. E.; Ricketts, J. W.; Tafoya, A. J.; Anan, T.; Mohammed, A.; Asmerom, Y.; Polyak, V.; Farouk, S.

    2012-12-01

    Quaternary climate in North Africa was marked by multiple wet periods overprinting extreme aridity, but pluvial drivers, as well as their timing and geographic extent, are poorly constrained. We address these factors in the first comprehensive analysis of travertine from Egypt's Western Desert, which represents a unique and under-utilized record of paleoclimate and paleohydrology. We infer large-volume travertine mound deposition along faults near the area's central limestone plateau to reflect times of high discharge (high groundwater head) from springs of the Nubian aquifer, likely associated with so-called Green Sahara pluvial episodes. Similarly, we assume that travertine platforms in depressions (oases) represent related marsh and lake deposition, including a widespread late Cenozoic dolostone of probable lacustrine origin in Farafra Oasis, which needs additional mapping. We present the results of uranium-series analysis of travertines from oasis areas spanning a north-south gradient through the Western Desert; we dated the tops and bottoms of inset deposits at different wadi (wash) elevations to resolve the inception and termination of high spring heads/pluvials as well as regional aggradation or incision patterns. Our dates, combined with published literature ages, suggest wet intervals around 100-115, 125-140, 180-200, 350-360, 450, and 600 ka. Heights of inset terrace travertines in wadis are potentially correlative between sites and are seen as approximately 5, 10, and 25 m above the modern wadi levels. Assuming that paleohydrological changes reflect paleoclimate changes, we examine correlations between times of travertine deposition, relative to glacial cycles or to more specific orbital forcings, acting on the North African summer monsoon. Initial comparison of travertine occurrence to glacial cycles shows no obvious correlation, although there are major travertine deposition episodes at important paleoclimate transitions such as MIS 6 to 5, 7 to 6, and

  6. Remote Sensing and Shallow Geophysical Investigations on Moghra Lake in Northeastern Qattarra Depression, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Khan, S. D.; Fathy, M. S.; Azeem, M. A.

    2012-12-01

    The Western Desert of Egypt encompasses two thirds of the land area of Egypt and constitutes one of the driest regions of the Sahara. This desert has seven depressions; Siwa, Qattara, Fayium, Bahariya, Farafra, Dakhla and Kharga. These depressions may be the manifestation of old drainage basins with extensive erosion and possibly some tectonic activity. Several oases with freshwater can be found in these depressions. Geological and geophysical investigations in Qattara Depression indicate several buried fluvial channels with flow direction from highlands in southeast to northwest. Moghra Lake at the northeastern tip of Qatarra basin may be a small remnant of a larger paleo-lake including the mouth of a paleo-river. This study probed this area for presence of buried channels that may have fed the larger Moghra paleo-lake. We have used ALOS - PALSAR radar remote sensing data to identify the surface features in this region, such as channels, channel fills, and fractures. In addition, dual polarization PALSAR data (HV, HH) allowed analysis of the near surface geology and assisted in delineating areas of interest for GPR surveys. GPR data along 2D profiles were acquired using the GSSI SIR-3000 system with a 400 MHz antenna that provided images to approximately three meters in depth. All the GPS data were processed using RADAN 6.6 software. A conventional processing flow was used for data processing: The positional correction tool removed the air wave. A range-gain balanced the amplitudes and a final band-pass (50 kHz to 500 kHz) filter was applied to the data. Deconvolution was also applied for highlighting the finer details. In addition, spatial filters were used to attenuate continuous vertical noise. The migrated sections of GPR identified a major paleochannel distributary with two minor channels at the margins. The bedrock of the studied area consists of the Lower Miocene Moghra Formation (sandstone and shale intercalations). The area around the present lake is

  7. The geochemistry of uranium and thorium isotopes in the Western Desert of Egypt

    SciTech Connect

    Dabous, A.A.

    1994-11-01

    The concentrations of {sup 238}U, {sup 234}U, {sup 232}Th, and {sup 228}Th have been measured in the groundwaters of the Bahariya and Farafra oases of the Western Desert of Egypt. These waters are characterized by normal amounts of U, but unusually high concentrations of Th. The pattern of variation of the parent isotopes, {sup 238}U and {sup 232}Th, as well as the daughter isotopes, {sup 234}U, {sup 230}Th, and {sup 228}Th, is systematic within and between the two oases. From the unusually consistent distribution of the {sup 234}U/{sup 238}U activity ratios one can conclude that the samples from both oases are representative of a two-component mixing system. One component, characterized by low U content and a high {sup 234}U/{sup 238}U activity ratio, is typical of deep artesian systems and probably represents flowthrough water derived from the Nubian highlands to the south. The second component is characterized by a greater U concentration and a low activity ratio. This signature is hypothesized as being derived by leaching of downward infiltrating water during pluvial times. The source of the U may be the uraniferous phosphate strata that overly the sandstone aquifer in both oasis areas. Higher Th values are associated with the artesian flow component of the mixing system and suggests that Th-bearing minerals may be abundant in the Nubian sandstone aquifer. The distribution of {sup 230}Th and {sup 228}Th in the water samples supports this interpretation.

  8. Origin of the gypsum-rich silica nodules, Moghra Formation, Northwest Qattara depression, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El Khoriby, Essam M.

    2005-06-01

    Gypsum rich-silica nodules appear in two shale horizons of the Moghra Formation (early Miocene) northwestern Qattara Depression, Western Desert, Egypt. These nodules are gray to milky white in colour, mostly botroidal and rose-like in shape and range in diameter from 2 to 7.5 cm. The silica nodule-bearing shale is composed mainly of smectite with a little minor kaolinite. The silica nodules consist mainly of quartz and are composed of gypsum-free matrix and gypsum-rich megacrystalline quartz. The matrix consists of microflamboyant quartz (less than 36 μm in diameter) and chalcedony. The megacrystalline quartz occurs as lenticular and prismatic forms (length: 90-250 μm; width: 30-90 μm). The microprobe, petrographic and SEM examinations confirmed the occurrence of gypsum relics (diameter; 2-16 μm) within the megacrystalline quartz. The chalcedony and mosaic microcrystalline quartz occurs as pore-lining and pore-filling cements. The structure of the silica nodules begins with quartzine in its outer rim, then gypsum-free microcrystalline quartz in the middle part and ends with gypsum-rich lenticular to prismatic megaquartz in the center. Field study, petrographic examination and microprobe analysis reveal that the silica nodules were formed by silicification of precursor gypsum nodules deposited in a marginal sabkha environment under an arid climate. The silicification selectively affected the gypsum nodules rather than the surrounding shale and occurred both through gypsum replacement and void filling. Transformation of isopachous chalcedony into mosaic microcrystalline quartz also occurred. The texture of the silica minerals reflects the different physico-chemical conditions under which they crystallized. Spherical nodules grew chiefly by the diffusive supply of the silica, and elongated ones grew by pore water advection. The integrated effect of climate, pH, salinity, crack systems within the sediment and oscillation in the groundwater level and its chemical

  9. Geochemistry and microprobe investigations of Abu Tartur REE-bearing phosphorite, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Awadalla, Gamal S.

    2010-07-01

    Phosphorites in Egypt occur in the Eastern Desert, the Nile Valley and the Western Desert at Abu Tartur area and present in Duwi Formation as a part of the Middle Eastern to North African phosphogenic province of Late Cretaceous to Paleogene age (Campanian-Maastrichtian). The Maghrabi-Liffiya phosphorite sector is considered as the most important phosphorite deposits in the Abu Tartur area due to its large reserve thickness and high-grade of lower phosphorite bed beside high content of REE. Back scattered electron (BSE) images show framboidal pyrite filling the pores of the phosphatic grains, suggesting diagenetic reducing conditions during phosphorites formation. Electron Probe Micro Analyzer (EPMA) chemical mapping was conducted to examine the variation and distributions of selected elements (P, F, La, Fe, Yb, Si, Ce, W, Eu, S, Ca, Y and Er) within the shark teeth, coprolites and bone fragments. In the teeth W, S, Fe are concentrated along the axis of the teeth, the bone fragments show high concentration of W, Yb, Er and Eu, whereas coprolites are nearly homogenous in composition contains S, Er with some Si as micro-inclusions. Fluorapatite is considered as main phosphate mineral whereas pyrite occurs as pore-filling within the phosphatic grains and cement materials. Maghrabi-Liffiya samples show a wide range in the P 2O 5 content, between 19.8 wt.% and 29.8 wt.% with an average of 24.6 wt.% and shows low U content ranging from 15 ppm to 34 ppm with an average of 22 ppm. The total REE content in nine samples representing the Maghrabi-Liffiya ranges from 519 to 1139 ppm with an average of about 879 ppm. The calculation of LREE (La-Gd) show indeed a marked enrichment relative to the HREE (Tb-Lu) where LREE/HREE ratio attains 8.4 indicating a strong fractionation between the LREE and HREE. Chondrite-normalized REE patterns of the studied phosphorite samples show a negative Eu anomaly.

  10. Travertine from Egypt's Western Desert: a terrestrial proxy for North African paleohydrology and paleoclimate during the Quaternary

    NASA Astrophysics Data System (ADS)

    Jimenez, G.; Crossey, L. J.; Karlstrom, K. E.; Polyak, V. J.; Asmerom, Y.

    2013-12-01

    The 'Green Sahara' pluvial phases that overprinted North African aridity during the Pleistocene are well recognized in tropical and Mediterranean marine records. Comparatively few studies have investigated the terrestrial expression of these pluvials, though, in part because of the paucity of paleohydrology archives in the desert. In this study, we show that travertine in Egypt's Western Desert constitutes a unique terrestrial proxy for the North African hydrologic cycle. In the Western Desert, travertine (defined inclusively as chemically-precipitated continental carbonate) deposits in paleo-oasis springs during times of high hydrologic head. Since head increases as meteoric precipitation falls in southern groundwater recharge areas, large-scale travertine accumulations can record pluvial episode durations as well as their geochemical characteristics. We built a database of new and previously-published U/Th ages from five paleo-oasis areas spanning a north-south gradient through the Western Desert. Integrating this geochronology with stable isotope and 87Sr/86Sr geochemistry of travertine samples, we present a terrestrial record of North African pluvial periods for the last ~650 ka. We show that groundwater sources for travertine remain constant through space and time, implying hydrological similarity between pluvial periods. The timing of travertine deposition is inconsistent over shorter (~10 ka) timescales in the various paleo-oases, though, suggesting that local hydrology may obscure the travertine response to pluvials. However, we observe significant travertine deposition across several areas between approximately 100 to 300 ka, and 450 to 600 ka, with a hiatus in between; we interpret these depositional 'peaks' to correspond with maxima in the 400-ka component of eccentricity. Thus, contrary to prior literature, we find that travertine deposition in the Western Desert, and thus pluvial occurrence, responds to orbitally-paced changes in equatorial insolation

  11. Palynostratigraphic Studies of the Lower Cretaceous Sediments, Alamein Formation, Bahrein-1 Well in the Northern Part of the Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Lashin, Gamal M. A.

    Palynostratigraphic studies of the Lower Cretaceous sediments, Alamein Formation, Bahrein-1 well in the northern part of the Western Desert, Egypt, have been carried out from an evolutionary and geological viewpoint. The palynoflora principally consists of pteridophytes, gymnosperms and some rare angiosperm pollen. The microflora shows that the palaeoenvironments were favorable for different kinds of plants. The recovered microflora, therefore, indicates an Early Aptian age and can be extended to the Early Albian. The palynological data revealed that the North Western Desert (N.W.D.) of Egypt belongs to the North Gondwana phytogeoprovince in the Early Cretaceous.

  12. Diagenetic origin of ironstone crusts in the Lower Cenomanian Bahariya Formation, Bahariya Depression, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Afify, A. M.; Sanz-Montero, M. E.; Calvo, J. P.; Wanas, H. A.

    2015-01-01

    In this paper, a new interpretation of the ironstone crusts of the Bahariya Formation as late diagenetic products is provided. The siliciclastic Lower Cenomanian Bahariya Formation outcropping in the northern part of the Bahariya Depression (Western Desert, Egypt) is subdivided into three informal units that are mainly composed of thinly laminated siltstone, cross-bedded and massive sandstone, fossiliferous sandstone/sandy limestone and variegated shale. Abundant ironstone crusts occur preferentially within its lower and upper units but are absent in the middle unit. The ironstone crusts show selective replacement of carbonate components, including calcretes, by iron oxyhydroxides. More permeable parts of the terrigenous beds such as burrow traces, subaerial exposure surfaces, concretionary features and soft-sediment deformation structures led to heterogeneous distribution of the iron oxyhydroxides. A variety of diagenetic minerals, where goethite and hematite are the main end-products, were characterized by mineralogical analysis (XRD), petrography and SEM observation, and geochemical determinations (EMPA). Other diagenetic minerals include Fe-dolomite/ankerite, siderite, manganese minerals, barite, silica, illite/smectite mixed-layer, and bitumen. These minerals are interpreted to be formed in different diagenetic stages. Some minerals, especially those formed during eodiagenesis, show features indicative of biogenic activity. During burial, dolomite and ankerite replaced preferentially the depositional carbonates and infilled secondary porosity as well. Also during mesodiagenesis, the decomposition of organic matter resulted in the formation of bitumen and created reducing conditions favorable for the mobilization of iron-rich fluids in divalent stage. Telodiagenesis of the Cenomanian Bahariya deposits took place during the Turonian-Santonian uplift of the region. This resulted in partial or total dissolution of Fe-dolomite and ankerite which was concomitant to

  13. Environmental impact and natural hazards on Kharga Oasis monumental sites, Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Salman, A. B.; Howari, F. M.; El-Sankary, M. M.; Wali, A. M.; Saleh, M. M.

    2010-09-01

    Kharga Oasis monumental sites are important to the cultural heritage in the South Western Desert of Egypt. These sites are scattered on the floor of the oasis representing ancient civilizations. The studied sites include the Hibis, EI-Nadura, EI-Ghueita and El-Zayyan temples as well as El-Bagawat Cemetery. The present study found that natural hazards have remarkable impacts on these sites. The impact of weathering processes, encroachment of sand dunes, stability of foundation beds and shallow groundwater seepage were documented. The present study found that humidity, temperature, sunlight and water content conditions seem to be favorable for biodegradation as evidenced by the presence of algae, bat blood and bird excretions. The radioactivity levels at the investigated sites are also measured via gamma-ray spectrometry. Sand dunes in the area pose a serious natural threat to the monumental sites. Active sand dunes are rapidly encroaching upon the components of these monuments, partially covering some monuments such as El-Ghueita Temple. These dunes load wind storms with fine sand particles. This causes wind erosion through sand blasting of these sites. Some monuments, such as EI-Nadura, EI-Ghueita and El-Zayyan temples were constructed on a suitable hard sandstone ground, whereas others, such as the Hibis Temple, were constructed on unsuitable soft shale ground in relatively topographically low area. The impact of the unstable foundation and shallow groundwater levels have caused severe structural damage as evidenced by tilted columns, cracked walls and salt-crystal growth in the porous building stones. These destructive elements threaten some other temples in Kharga Oasis and will eventually cause total physical collapse. Although rain is rare in this area, it can form a real threat to mud brick monuments such as El-Bagawat Cemetery. The natural radioactivity sources resulted in an annual effective dose equivalent values averaging 0.20, 0.13, 0.09 and 0.07 m

  14. Upper Paleocene-Lower Eocene biostratigraphy of Darb Gaga, Southeastern Kharga Oasis Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Ouda, Khaled; Berggren, William A.; Abdel Sabour, Ayman

    2016-06-01

    Paleontological studies on the Upper Paleocene-Lower Eocene succession at Darb Gaga, southeastern Kharga Oasis, Western Desert, Egypt document the changes associated with the Paleocene-Eocene Thermal Maximum (PETM), such as 1) a radical alteration of the relative and absolute abundance of planktonic foraminifera; 2) a massive occurrence of the excursion planktonic foraminiferal taxa; 3) a widespread deposition of calcarenite yielding atypical (extremely high) faunal abundance associated with the younger phase of warming; and 4) a concentration of coprolites associated with the middle phase of warming. We also document the Lowest Occurrence (LO) of dimorphic larger benthic and excursion foraminifera during the earlier phase of warming at Darb Gaga, as recorded in Bed 1 of the Dababiya Quarry Member. The absence of these faunas in Bed 1 at Dababiya (the GSSP for the P/E Boundary) is likely to be due to both intense deficiency in dissolved oxygen and massive carbonate dissolution. Only remains (fish remains) of faunas that can tolerate the toxicity produced by low oxygen conditions are found in the stratigraphic record of this (oldest) phase at Dababiya. The Dababiya Quarry Member (DQM) at Darb Gaga reflects the unfolding of the sedimentary and biotic changes associated with the PETM global warming at, and following, the Paleocene/Eocene boundary on the southern Tethys platform. The changes began with a rapid increase in bottom and "intermediate" water temperature. The temperature increase was accompanied by removal of oxygen during the early and middle stages of warming. This led to the absence of both subbotinids and calcareous benthic foraminifera in the early and second coprolite-bearing phases (Beds 2 and 3 of the DQM). Dissolution seems to have no role during these stages as shown by the unusual abundance and good preservation of the warm-tolerant Ac. sibaiyaensis. This species reaches its maximum abundance in Bed 2 where it exhibits a broad range of size (63

  15. Paleocene-Eocene transition at Naqb Assiut, Kharga Oasis, Western Desert, Egypt: Stratigraphical and paleoenvironmental inferences

    NASA Astrophysics Data System (ADS)

    El-Dawy, Moustafa, Hassan; Obaidalla, Nageh Abdelrahman; Mahfouz, Kamel Hussien; Abdel Wahed, Samar Adel

    2016-05-01

    This work depends on the study of the lower part of the Esna Formation which encompasses the Paleocene-Eocene (P-E) transition in Egypt as well as at Naqb Assiut section, Kharga Oasis, Western Desert. The Paleocene/Eocene (P/E) boundary is represented by El Dababiya Quarry Member which consists of five distinctive beds (nos. 1-5) at the GSSP. On the other hand, at Naqb Assiut section this boundary is only represented by the upper two beds (nos. 4&5), whereas, the lower three beds (nos. 1-3) are missing due to a hiatus. This hiatus is marked by the occurrence of an irregular surface contains pebbles and phosphatic materials. This hiatus may be related to the echo of Sryian Arc Orogeny at the P/E time. Biostratigraphically; four planktonic foraminiferal zones are defined from base to top as: Acarinina soldadoensis/Globanomalina pseudomenardii and Morozovella velascoensis (late Paleocene), Acarinina sibaiyaensis and Pseudohastigerina wilcoxensis/Morozovella velascoensis (early Eocene). The Acarinina sibaiyaensis Zone which represents the P//E/boundary is characterized by the occurrence of intrazonal hiatus at it's lower part. The benthonic foraminiferal taxa contain abundant representatives of Midway-type fauna (∼91% of the whole assemblages), beside few Velasco-type faunal ones (∼9%), indicating an outer neritic (150-200 m) water depth of deposition during the P-E transition. Quantitative analysis and composition of benthonic foraminiferal assemblages are indicative for various environmental changes around the P/E boundary. They reflected a high diversity, increase of epifaunal taxa, and low-intermediate productivity conditions, which indicates a well-ventilated bottom water and oligo - to mesotrophic conditions during the late Paleocene age. Rapid extinction of about 18% of the entire benthonic foraminiferal species started at the P/E boundary, where the last occurrence of Angulogavelinella avnimelechi is pronounced at the base of this boundary. There is a

  16. Paleocene-Eocene transition at Naqb Assiut, Kharga Oasis, Western Desert, Egypt: Stratigraphical and paleoenvironmental inferences

    NASA Astrophysics Data System (ADS)

    El-Dawy, Moustafa, Hassan; Obaidalla, Nageh Abdelrahman; Mahfouz, Kamel Hussien; Abdel Wahed, Samar Adel

    2016-05-01

    This work depends on the study of the lower part of the Esna Formation which encompasses the Paleocene-Eocene (P-E) transition in Egypt as well as at Naqb Assiut section, Kharga Oasis, Western Desert. The Paleocene/Eocene (P/E) boundary is represented by El Dababiya Quarry Member which consists of five distinctive beds (nos. 1-5) at the GSSP. On the other hand, at Naqb Assiut section this boundary is only represented by the upper two beds (nos. 4&5), whereas, the lower three beds (nos. 1-3) are missing due to a hiatus. This hiatus is marked by the occurrence of an irregular surface contains pebbles and phosphatic materials. This hiatus may be related to the echo of Sryian Arc Orogeny at the P/E time. Biostratigraphically; four planktonic foraminiferal zones are defined from base to top as: Acarinina soldadoensis/Globanomalina pseudomenardii and Morozovella velascoensis (late Paleocene), Acarinina sibaiyaensis and Pseudohastigerina wilcoxensis/Morozovella velascoensis (early Eocene). The Acarinina sibaiyaensis Zone which represents the P//E/boundary is characterized by the occurrence of intrazonal hiatus at it's lower part. The benthonic foraminiferal taxa contain abundant representatives of Midway-type fauna (∼91% of the whole assemblages), beside few Velasco-type faunal ones (∼9%), indicating an outer neritic (150-200 m) water depth of deposition during the P-E transition. Quantitative analysis and composition of benthonic foraminiferal assemblages are indicative for various environmental changes around the P/E boundary. They reflected a high diversity, increase of epifaunal taxa, and low-intermediate productivity conditions, which indicates a well-ventilated bottom water and oligo - to mesotrophic conditions during the late Paleocene age. Rapid extinction of about 18% of the entire benthonic foraminiferal species started at the P/E boundary, where the last occurrence of Angulogavelinella avnimelechi is pronounced at the base of this boundary. There is a

  17. Eolian features in the Western Desert of Egypt and some applications to Mars.

    USGS Publications Warehouse

    El-Baz, F.; Breed, C.S.; Grolier, M.J.; McCauley, J.F.

    1979-01-01

    Relations of landform types to wind regimes, bedrock composition, sediment supply, and topography are shown by field studies and satellite photographs of the Western Desert. This desert provides analogs of Martian wind-formed features and sand dunes, alternating light and dark streaks, knob 'shadows' and yardangs. Surface particles have been segregated by wind into dunes, sand sheets, and light streaks, that can be differentiated by their grain size distributions, surface shapes, and colors. Throughgoing sand of mostly fine to medium grain size is migrating S in longitudinal dune belts and barchan chains whose long axes lie parallel to the prevailing W winds, but topographic variations such as scarps and depressions strongly influence the zones of deposition and dune morphology. -from Authors

  18. Sedimentary cover in the South Western Desert of Egypt as deduced from Bouguer gravity and drill-hole data

    NASA Astrophysics Data System (ADS)

    Senosy, M. M.; Youssef, M. M.; Abdel Zaher, M.

    2013-06-01

    The Western Desert, Egypt includes the major groundwater aquifer in the country. It is apart from the Major Sahara Nubian Aquifer which is present in Sudan, Chad, Egypt and Libya. Thickness of this aquifer is changed laterally from south to north and also from west to east. The changes may structurally or litheologicalley control. The present study is focused on using of Bouguer gravity anomaly mapped at a scale of 1:500,000 and the lithological logs of about 120 deep wells used to determine the thickness of the sedimentary sequence containing the main Nubian sandstone water aquifer in important area of Egypt. The area is located in the southern part of the Western Desert bounded by the latitudes 22°00'-26°30'N, and longitudes 28°30'-33°00'E. The predominant structures affecting the basement rocks and the sedimentary cover were traced and analyzed. The gravity stripping approach was applied to eliminate the gravity effects caused by sedimentary sequence and to separate density anomalies within the sedimentary fill from the influence of rocks at deeper levels in the crystalline crust. The study indicated that the surface of the basement rocks is highly rugged and mostly controlled by structures which have a direct effect on thickness variation of the sedimentary cover all over the area. Regionally the area is characterized by two major intracratonic basins (the Dahkla Basin and the Nile valley Basin) separated by a NE-SW trending swell of the Kharga uplift and bounded at the south by the Oweinat-Bir Safsaf-Aswan uplift. These major tectonic units are controlled by fault structures trending in N-S, E-W, NE-SW, NW-SE, which cut the basement rocks and extend upward in the sedimentary cover. The maximum thickness of sandstone formations is recorded at west Oweinat, west Kurkur, southwest of Aswan, Gramashin, Dakhla oasis and some localities west of Sohag and Qena towns. At these localities the thickness ranges between 600 and 900 m. As this formation is the main

  19. The history and fate of the Nubian Sandstone Aquifer springs in the oasis depressions of the Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Powell, Owen; Fensham, Rod

    2016-03-01

    Extraction of groundwater for agriculture has resulted in the loss of springs across arid regions of the globe. The history and fate are recorded of the artesian springs of Egypt's Western Desert, from ancient times to the present, spanning the rise and fall of the great civilisations from the Pharoanic dynasties to Persian, Greek and Roman conquests. The study area includes oases Kharga, Dakhla, Bahriya, Farafra and Siwa, and several outer and small oases around Siwa and the edge of the Qattara Depression. The region is hyper-arid, receiving 10 mm or less average annual precipitation and evaporation rates are in the vicinity of 3,000 mm/a. Groundwater in the oases is largely derived from bores discharging from the Nubian Sandstone Aquifer. Based on an extensive survey, conducted for the first time, attention is drawn to the rapid demise of springs as a result of modern irrigation schemes which continue to deplete groundwater supplies.

  20. Geoenvironmental assessment of the SIWIA area Oasis, Western Desert, Egypt, using geographical and hydrological information systems

    NASA Astrophysics Data System (ADS)

    Faid, A.; Ismail, E.; Birk, S.

    2012-04-01

    Overpopulation of Egypt has put pressure on the government for horizontal expansion for food security. Therefore, horizontal expansion in the desert for agricultural purposes is one of the solutions. Groundwater represents the main source of water supply in Siwa Oasis. The sedimentary succession comprises different water bearing formations. These aquifers bear groundwater ranging in its salinity from fresh water to brine one. These aquifers are the Quaternary deposits, the Miocene carbonate, the Eocene carbonate, the Upper Cretaceous, the Cretaceous Nubian sandstone beside Carboniferous, Devonian, Silurian and Cambrian-Ordovicean sandstone aquifers. The Paleozoic sandstone has brine water but the Mesozoic one (Cretaceous Nubian sandstone) has fresh one. The Cretaceous Nubian sandstone represents the source of exploited water in the area, where it recharges the overlying carbonate aquifers. Fifty seven wells are included in the present study to reveal the hydrogeologic conditions of the oasis. The fractured carbonate aquifers represent the main exploitable aquifers due to their availability for the farmers in spite the low water quality. The water of this aquifer has a wide range of salinity ranging from 2377 ppm to > 17000 ppm depending on the depth of aquifer and the nature of facies and fracturing of the rock. The Nubian sandstone aquifers represent the main source of water in the area where it bears fresh water (< 1000 ppm). The flow within the Nubian sandstone is directed to the area of high discharge, i.e. to the west. The groundwater of the Quaternary and the fractured carbonates reflects leaching processes (secondary salinity) and that of the Nubian sandstone reflects meteoric origin and recharge during the pluvial period. The groundwater resources are evaluated with respect to their suitability for different purposes. Depending on the present geomorphological and hydrogeological studies and the previous pedological studies a landuse map was constructed.

  1. SAR Remote Sensing of Buried Faults: Implications for Groundwater Exploration in the Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Gaber, Ahmed; Koch, Magaly; Helmi Griesh, M.; Sato, Motoyuki

    2011-12-01

    The hydrological setting of a desert plain area located in Egypt, west of Aswan city, is still not well understood, and thus, its groundwater potential remains largely unknown. Images from the ALOS/PALSAR L-band sensor have been used to detect and delineate the subsurface structures in this area. Linear, elliptical and circular polarization transformations were applied to the ALOS/PALSAR full polarimetric data by changing the orientation angle (ψ°) and elliptical angle (χ°). The circular polarization (ψ = 0° and χ = 45°) proved to be the best transformation for revealing buried faults in various strike directions, which have not been reported in the last version of the official geologic map of this area. Such derived circular polarization images were further enhanced by applying the Optimal Polarization Contrast Enhancement method. The moisture content ( Ө S ) of the study sites was generally low, with an average of roughly 0.01%. The average Root Mean Square Height (hRMS) of the surface roughness was also low with 0.01 cm across all sites. The relative dielectric constant (ɛ r ) of the sand in the study area produced a very low value of 3.04. The effects of Ө S , ɛ r and hRMS on the radar backscattered signals turned out to be very low, thus providing, optimal conditions for L-band to penetrate relatively deeply. Moreover, 21 GPR profiles were acquired using 270 MHz shielded antennas to validate the radar remote sensing results. These GPR profiles reveal obvious offsets in the subsurface stratigraphy suggesting that such highly fractured zones are possibly favorable zones for groundwater accumulation.

  2. Characteristics of NORM in the oil industry from eastern and western deserts of Egypt.

    PubMed

    Shawky, S; Amer, H; Nada, A A; El-Maksoud, T M; Ibrahiem, N M

    2001-07-01

    Naturally occurring radionuclides (NORs) from the 232Th- and 238U-series, which are omnipresent in the earth's crust, can be concentrated by technical activities, particularly those involving natural resources. Although, a great deal of work has been done in the field of radiation protection and remedial action on uranium and other mines, recent concern has been devoted to the hazard arising from naturally occurring radioactive materials (NORM) in oil and gas facilities. NORM wastes associated with oil and gas operations from scale deposits, separated sludge and water at different oil fields in the eastern and western deserts were investigated. Concentrations of the uranium, thorium, and potassium (40K) series have been determined from high-resolution gamma-ray spectrometry. Total uranium content of samples was determined using laser fluorimetry. The levels of radioactivity were mainly due to enhanced levels of dissolved radium ions. Only minute quantities of uranium and thorium were present. The disequilibrium factor for 238U/226Ra has been determined. PMID:11339530

  3. Subsurface geology of Tertiary rocks of northeastern district of Western Desert, Egypt

    SciTech Connect

    Elzarka, M.H.; Radwan, I.A.

    1983-03-01

    The lithofacies analysis of the Tertiary rocks reveals two ancient subbasins at the north and southeast of the northeastern district, Western Desert. The lithofacies of the Paleocene and early and middle Eocene sections are mainly calcareous. Shale predominates in the late Eocene rocks. The Paleocene rocks seem to have accumulated in a lagoonal environment of epineritic depths. The Paleocene rocks of the northern subbasin indicate accumulation on an unstable shelf. The Paleocene environmental conditions seem to have prevailed during the early and middle Eocene. During the late Eocene, rocks of shallow-water and current-agitated environments accumulated. The lower clastic layers of the Oligocene, having a sand/shale ratio less than one, indicate a clastic shoreline environment-lagoonal subenvironment. The Oligocene clastics are overlain by a basaltic sheet at the eastern part of the district. The middle Miocene lithofacies indicate rock accumulation in a contemporaneously subsiding basin under lagoonal or delta-front conditions at the southern part of the district. Marine stagnant-bottom-water conditions prevailed during the accumulation of the middle Miocene rocks at the norther parts. The Pliocene rocks seem to have accumulated in lagoons, where the inflow exceeded evaporation and alternating periods of exposure and flooding by either fresh or saline water of poor circulation prevailed. The tectonic instability of the district was initiated by volcancity during the late Oligocene.

  4. Groundwater Numerical Modeling, An Application of Remote Sensing, and GIS Techniquies in El Shab area, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Faid, Abdalla; Ismail, Esam

    2016-04-01

    El Shab region is located in south Darb El Arbaieen, western desert of Egypt. It occupies the area between latitudes 22o 00/ and 22o 30/ North and Longitudes 29o 30/ and 30o 00/ East, from southern border of Egypt to the area north Bir Kuraiym and from the area east of east Owienat to the area west Tushka district, its area about 2750 Km2. The famous features; southern part of Darb El Arbaieen road, G Baraqat El Scab El Qarra, Bir Dibis, Bir El Shab and Bir Kuraiym, Interpretation of soil stratification shows layers that are related to Quaternary and Upper-Lower Cretaceous eras. It is dissected by a series of NE-SW striking faults. The regional groundwater flow direction is in SW-NE direction with a hydraulic gradient is 1m / 2km. Mathematical model program has been applied for evaluation of groundwater potentials in the main Aquifer -Nubian Sandstone- in the area of study. Total period of simulation is 100 years. After steady state calibration, two different scenarios are simulated for groundwater development. 21 production wells are installed at the study area and used in the model, with the total discharge for the two scenarios were 105000m3/d, 210000m3/d. The drawdown was 11.8 m and 23.7 m for the two scenarios in the end of 100 year. Contour maps for water heads and drawdown and hydrographs for piezometric head are represented. The drawdown was less than the half of the saturated thickness (the safe yield case).

  5. Subsurface brine injection: Proactive approach to close the produced water loop in the western desert of Egypt

    SciTech Connect

    Farid, E.E.; Nour, M.H.

    1996-11-01

    In 1988 a major onshore production facility was producing oil from eight formations in six oil fields located in the western desert of Egypt. Two of these formations include active water drive reservoirs, in addition; three reservoirs at that date were receiving water injection to enhance oil recovery. To handle the increasing volumes of the produced water (which is contaminated with oil, production chemicals and other pollutants), three alternatives were investigated: (1) Injection into disposal wells. (2) Dumping in surface disposal pits. (3) Re-injection to waterflood some oil reservoirs. The investigation revealed that the first two options are technically unfavorable, also they are conventional Waste Management Technologies (WMT) which provide short-term remedial solution. In contrast, Produced Water Re-Injection (PWRI) is an Environmental Control Technology (ECT) which minimize the environmental impact through process improvements. A state -of-the-art re-injection process was utilized using chemical treatment, gas liberation, settling, filtration and injection. This process represents a combination of two (ECT) methods: Reuse (for water flooding) and Recycling (when brine is redisposed underground). This process reduce the overall volumes of produced water to be disposed, increase the oil reserves, reservoir pressure and oil production and converse the underground water reserve.

  6. Electrical and geochemical properties of tufa deposits as related to mineral composition in the South Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Gomaa, Mohamed M.; Abou El-Anwar, Esmat A.

    2015-06-01

    The geochemical, petrographical, and electrical properties of rocks are essential to the investigation of the properties of minerals. In this paper we will try to present a study of the A. C. electrical properties of carbonate rock samples and their relation to petrographical and geochemical properties. Samples were collected from four formations from the Bir Dungul area, in the South Western Desert, Egypt. The electrical properties of the samples were measured using a non-polarizing electrode, at room temperature (~28 °C), and at a relative atmospheric humidity of (~45%), in the frequency range from 42 Hz to 5 MHz. The changes in the electrical properties were argued to the change in mineral composition. Generally, the electrical properties of rocks are changed due to many factors e.g., grain size, mineral composition, grain shape and inter-granular relations between grains. The dielectric constant of samples decreases with frequency, and increases with conductor concentration. Also, the conductivity increases with an increase of continuous conductor paths between electrodes. The petrographical and geochemical studies reveal that the deposition of the tufa deposits occurred in shallow lakes accompanied by a high water table, an alkaline spring recharge and significant vegetation cover. Diagenetically, tufa deposits were subjected to early and late diagenesis. Petrography and geochemistry studies indicated that the area of tufa deposits was deposited under the control of bacterial activity. Geochemically, the Sr content indicates that the tufa deposits formed from dissolved bicarbonate under the control of microbes and bacterial activity.

  7. Petrophysical evaluation of the hydrocarbon potential of the Lower Cretaceous Kharita clastics, North Qarun oil field, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Teama, Mostafa A.; Nabawy, Bassem S.

    2016-09-01

    Based on the available well log data of six wells chosen in the North Qarun oil field in the Western Desert of Egypt, the petrophysical evaluation for the Lower Cretaceous Kharita Formation was accomplished. The lithology of Kharita Formation was analyzed using the neutron porosity-density and the neutron porosity-gamma ray crossplots as well as the litho-saturation plot. The petrophysical parameters, include shale volume, effective porosity, water saturation and hydrocarbon pore volume, were determined and traced laterally in the studied field through the iso-parametric maps. The lithology crossplots of the studied wells show that the sandstone is the main lithology of the Kharita Formation intercalated with some calcareous shale. The cutoff values of shale volume, porosity and water saturation for the productive hydrocarbon pay zones are defined to be 40%, 10% and 50%, respectively, which were determined, based on the applied crossplots approach and their limits. The iso-parametric contour maps for the average reservoir parameters; such as net-pay thickness, average porosity, shale volume, water saturation and the hydrocarbon pore volume were illustrated. From the present study, it is found that the Kharita Formation in the North Qarun oil field has promising reservoir characteristics, particularly in the northwestern part of the study area, which is considered as a prospective area for oil accumulation.

  8. Modeling of gas generation from the Alam El-Bueib formation in the Shoushan Basin, northern Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Shalaby, Mohamed Ragab; Hakimi, Mohammed Hail; Abdullah, Wan Hasiah

    2013-01-01

    The Shoushan Basin is an important hydrocarbon province in the northern Western Desert, Egypt, but the burial/thermal histories for most of the source rocks in the basin have not been assigned yet. In this study, subsurface samples from selected wells were collected to characterize the source rocks of Alam El-Bueib Formation and to study thermal history in the Shoushan Basin. The Lower Cretaceous Alam El-Bueib Formation is widespread in the Shoushan Basin, which is composed mainly of shales and sandstones with minor carbonate rocks deposited in a marine environment. The gas generative potential of the Lower Cretaceous Alam El-Bueib Formation in the Shoushan Basin was evaluated by Rock-Eval pyrolysis. Most samples contain sufficient type III organic matter to be considered gas prone. Vitrinite reflectance was measured at eight stratigraphic levels (Jurassic-Cretaceous). Vitrinite reflectance profiles show a general increase of vitrinite reflectance with depth. Vitrinite reflectance values of Alam El-Bueib Formation range between 0.70 and 0.87 VRr %, indicating a thermal maturity level sufficient for hydrocarbon generation. Thermal maturity and burial histories models predict that the Alam El-Bueib source rock entered the mid-mature stage for hydrocarbon generation in the Tertiary. These models indicate that the onset of gas generation from the Alam El-Bueib source rock began in the Paleocene (60 Ma), and the maximum volume of gas generation occurred during the Pliocene (3-2 Ma).

  9. 3D slicing of radiogenic heat production in Bahariya Formation, Tut oil field, North-Western Desert, Egypt.

    PubMed

    Al-Alfy, I M; Nabih, M A

    2013-03-01

    A 3D block of radiogenic heat production was constructed from the subsurface total gamma ray logs of Bahariya Formation, Western Desert, Egypt. The studied rocks possess a range of radiogenic heat production varying from 0.21 μWm(-3) to 2.2 μWm(-3). Sandstone rocks of Bahariya Formation have higher radiogenic heat production than the average for crustal sedimentary rocks. The high values of density log of Bahariya Formation indicate the presence of iron oxides which contribute the uranium radioactive ores that increase the radiogenic heat production of these rocks. The average radiogenic heat production produced from the study area is calculated as 6.3 kW. The histogram and cumulative frequency analyses illustrate that the range from 0.8 to 1.2 μWm(-3) is about 45.3% of radiogenic heat production values. The 3D slicing of the reservoir shows that the southeastern and northeastern parts of the study area have higher radiogenic heat production than other parts. PMID:23291561

  10. Precipitation source inferred from stable isotopic composition of Pleistocene groundwater and carbonate deposits in the western desert of Egypt.

    SciTech Connect

    Sultan, M.; Sturchio, N.; Hassan, F. A.; Abdel, M.; Hamdan, R.; Mahmood, A. M.; Alfy, Z. E.; Stein, T.; Environmental Research; Univ. Coll. London; Cairo Univ.; Ain Shams Univ.; Egyptian Geological survey and Mining Authority; Washington Univ.

    1997-01-01

    An Atlantic source of precipitation can be inferred from stable isotopic data (H and O) for fossil groundwaters and uranium-series-dated carbonate spring deposits from oases in the Western Desert of Egypt. In the context of available stable isotopic data for fossil groundwaters throughout North Africa, the observed isotopic depletions ({delta}D -72 to -81{per_thousand}; {delta}{sup 18}O -10.6 to -11.5{per_thousand}) of fossil ({ge}32,000 yr B.P.) groundwaters from the Nubian aquifer are best explained by progressive condensation of water vapor from paleowesterly wet oceanic air masses that traveled across North Africa and operated at least as far back as 450,000 yr before the present. The values of {delta}{sup 18}O (17.1 to 25.9{per_thousand}) for 45,000- to >450,000-yr-old tufas and vein-filling calcite deposits from the Kharga and Farafra Oases are consistent with deposition from groundwaters having oxygen isotopic compositions similar to those of fossil groundwaters sampled recently at these locations.

  11. Vertebrate paleontological exploration of the Upper Cretaceous succession in the Dakhla and Kharga Oases, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Sallam, Hesham M.; O'Connor, Patrick M.; Kora, Mahmoud; Sertich, Joseph J. W.; Seiffert, Erik R.; Faris, Mahmoud; Ouda, Khaled; El-Dawoudi, Iman; Saber, Sara; El-Sayed, Sanaa

    2016-05-01

    The Campanian and Maastrichtian stages are very poorly documented time intervals in Africa's record of terrestrial vertebrate evolution. Upper Cretaceous deposits exposed in southern Egypt, near the Dakhla and Kharga Oases in the Western Desert, preserve abundant vertebrate fossils in nearshore marine environments, but have not yet been the focus of intensive collection and description. Our recent paleontological work in these areas has resulted in the discovery of numerous new vertebrate fossil-bearing localities within the middle Campanian Qusier Formation and the upper Campanian-lower Maastrichtian Duwi Formation. Fossil remains recovered from the Campanian-aged Quseir Formation include sharks, rays, actinopterygian and sarcopterygian fishes, turtles, and rare terrestrial archosaurians, including some of the only dinosaurs known from this interval on continental Africa. The upper Campanian/lower Maastrichtian Duwi Formation preserves sharks, sawfish, actinopterygians, and marine reptiles (mosasaurs and plesiosaurs). Notably absent from these collections are representatives of Mammalia and Avialae, both of which remain effectively undocumented in the Upper Cretaceous rocks of Africa and Arabia. New age constraints on the examined rock units is provided by 23 nannofossil taxa, some of which are reported from the Duwi Formation for the first time. Fossil discoveries from rock units of this age are essential for characterizing the degree of endemism that may have developed as the continent became increasingly tectonically isolated from the rest of Gondwana, not to mention for fully evaluating origin and diversification hypotheses of major modern groups of vertebrates (e.g., crown birds, placental mammals).

  12. Magnetization of three Nubia Sandstone formations from Central Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    El-Shayeb, H.; El-Hemaly, I. A.; Abdel Aal, E.; Saleh, A.; Khashaba, A.; Odah, H.; Mostafa, R.

    2013-06-01

    A total of 198 oriented cores (from 16 sites) have been sampled from three Cretaceous Nubia sandstone formations distributed around the Kharga-Dakhla and Dakhla-Uwainat roads in the Western Desert for paleomagnetic studies. Two of these formations are of the Early Cretaceous (the Six Hills, Abu Ballas formations) and the third one is of the Late Cretaceous (Maghrabi formation). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment. Rock magnetic experiments reveal that the presence of hematite is the main magnetic mineral in the three formations. Therefore, present study relies mostly on thermal demagnetization. Two magnetic components have been isolated from the studied rocks. The first component has been isolated from the Six Hills and Abu Ballas formations and is carried by hematite with D = 347.1°, I = 41.6° with α95 = 7.8° and the corresponding pole lies at lat. = 78.2° N and long. = 294.1° E. The second component has been isolated from the Maghrabi formation and is carried also by hematite with D = 22.7°, I = 28.4° with α95 = 9.9° and pole position lies at lat. = 66.3° N and long. = 140.6° E. The first magnetic component obtained from the two older formations is considered primary, as the corresponding pole reflects the age when compared with the previously obtained Cretaceous poles for North Africa. On other hand, the second pole obtained from the Maghrabi formation (the younger) is inconsistent with the Cretaceous pole positions for North Africa, but falls closer to the Eocene pole indicating that the rocks of this formation could have suffered remagnetization during the late Eocene time.

  13. Sedimentology, sequential analysis and clay mineralogy of the lower Eocene sequence at Farafra Oasis area, Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    El Ayyat, Abdalla M.

    2013-02-01

    Integrated sedimentological studies, sequential analysis and clay mineralogy on the lower Eocene rocks in the Western Desert provided important information on the reconstruction of the depositional basin, cyclicity, and paleoclimatic conditions. Two formations are recognized; the Esna and Farafra formations, with a gradational contact in-between. The studied sequence exhibits lateral facies changes as revealed from field and microfacies investigations. Eight facies were recognized and summarized in a carbonate ramp model. It represents also a general regressive trend, which records a transition from an outer ramp into a peritidal zone. The facies stacking patterns constitute several kinds of meter-scale, shallowing-upward cycles. Two different types of depositional cycles are here defined. The stratigraphic sections show a hierarchical organization of many cycles defined by five depositional sequences. It is suggested that composite eustatic sea level oscillations caused by cyclic perturbations of the Earth's orbit played a fundamental role in determining the formation of the observed hierarchical cyclic organization. Summing up, it is believed that the paleotopography had resulted from the impact of the Syrian Arc Folding System. A confusing additional complication is introduced by syndepositional sedimentary structures, especially during the late Cretaceous/Eocene times, coupled by several tensional forces. Clay mineralogy has revealed the presence of smectite, kaolinite and illite. Their origin may be attributed to the gradual increase in the amount of erosion of the newly elevated crystalline source rocks to the south of Egypt, in areas of moderate rainfall and rapid weathering and/or to reworking processes of soils which presumably developed on basement rocks. Changes in source rocks or climatic influence during the early Eocene may account for the observed differences in clay mineral abundances.

  14. Palynostratigraphy and paleoenvironmental significance of the Cretaceous succession in the Gebel Rissu-1 well, north Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El Beialy, Salah; El-Soughier, Maher; Mohsen, Sayed Abdel; El Atfy, Haytham

    2011-02-01

    Palynological investigation of the Cretaceous Abu Roash, Bahariya, Kharita, Alamein, Alam El Bueib and Betty formations, encountered in the Gebel Rissu-1 well, north Western Desert, Egypt yielded 27 species of pteridophytic spores, 24 of gymnosperm pollen, 25 of angiosperm pollen and 11 of dinoflagellate cysts in addition to some acritarchs, foraminiferal test linings and freshwater algae. This enabled us to recognize five miospore biozones arranged from youngest to oldest as: Classopollis brasiliensis- Afropollis cf. kahramanensis- Dichastopollenites ghazalataensis Assemblage Zone (Late Cenomanian); Elaterosporites klaszii- Sofrepites legouxae- Afropollis jardinus Assemblage Zone (Middle/Late Albian-Early Cenomanian); Pennipollis peroreticulatus- Duplexisporites generalis-Tricolpates Assemblage Zone (Early Aptian-Early Albian); Tucanopollis crisopolensis- Afropollis sp. Assemblage Zone (Barremian) and Appendicisporites cf. tricornitatus- Ephedripites spp. Assemblage Zone (Late Neocomian). The Early Cretaceous Kharita, Alam El Bueib and the Betty formations encountered in the Gebel Rissu-1 well are interpreted to indicate oxic proximal and distal shelf deposits, characterized by type III/IV, V kerogen, which is gas prone but having little potential to produce hydrocarbons. The Upper Cretaceous Abu Roash and Bahariya formations are characterized by a distal suboxic-anoxic and marginal dysoxic-anoxic environment, and their kerogen type III/II indicates gas/oil prone nature. The Bahariya and Kharita Albian-Cenomanian sediments in the present study witnessed the onset of a semi-arid to arid climate, with local or seasonal humid conditions, based on the continuous high abundance of the elaterates pollen and Afropollis-producing plants that inhabited the paleotropical humid coastal plains.

  15. Correlation of Aerogravity and BHT Data to Develop a Geothermal Gradient Map of the Northern Western Desert of Egypt using an Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Mohamed, Haby S.; Abdel Zaher, Mohamed; Senosy, Mahmoud M.; Saibi, Hakim; El Nouby, Mohamed; Fairhead, J. Derek

    2015-06-01

    The northern part of the Western Desert of Egypt represents the second most promising area of hydrocarbon potential after the Gulf of Suez province. An artificial neural network (ANN) approach was used to develop a new predictive model for calculation of the geothermal gradients in this region based on gravity and corrected bottom-hole temperature (BHT) data. The best training data set was obtained with an ANN architecture composed of seven neurons in the hidden layer, which made it possible to predict the geothermal gradient with satisfactory efficiency. The BHT records of 116 deep oil wells (2,000-4,500 m) were used to evaluate the geothermal resources in the northern Western Desert. Corrections were applied to the BHT data to obtain the true formation equilibrium temperatures, which can provide useful constraints on the subsurface thermal regime. On the basis of these corrected data, the thermal gradient was computed for the linear sections of the temperature-versus-depth data at each well. The calculated geothermal gradient using temperature log data was generally 30 °C/km, with a few local high geothermal gradients in the northwestern parts of the study area explained by potential local geothermal fields. The Bouguer gravity values from the study area ranged from -60 mGal in the southern parts to 120 mGal in the northern areas, and exhibited NE-SW and E-W trends associated with geological structures. Although the northern Western Desert of Egypt has low regional temperature gradients (30 °C/km), several potential local geothermal fields were found (>40 °C/km). The heat flow at each well was also computed by combining sets of temperature gradients and thermal conductivity data. Aerogravity data were used to delineate the subsurface structures and tectonic framework of the region. The result of this study is a new geothermal gradient map of the northern Western Desert developed from gravity and BHT log data.

  16. Larger benthic foraminiferal turnover across the Eocene-Oligocene transition at Siwa Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Orabi, H.; El Beshtawy, M.; Osman, R.; Gadallah, M.

    2015-05-01

    In the Eocene part of the Siwa Oasis, the larger foraminifera are represented by the genera Nummulites, Arxina, Operculina, Sphaerogypsina, Asterocyclina, Grzybowskia, Silvestriella, Gaziryina and Discocyclina in order of abundance. Operculina continues up to the early Oligocene as modern representatives in tropical regions, while the other genera became extinct. Nevertheless, the most common larger foraminiferal genus Lepidocyclina (Nephrolepidina) appears only in the lowermost Oligocene. In spite of the Eocene-Oligocene (E/O) transition is thought to have been attended by major continental cooling at northern middle and high latitudes, we discover that at the Siwa Oasis, there is a clear warming trend from the late Eocene (extinction level of Nummulites, Sphaerogypsina, Asterocyclina, Grzybowskia, Silvestriella and Discocyclina) to the early Oligocene is observed due to the high abundance of Operculina and occurrence of kaolinite and gypsiferous shale deposits in both Qatrani and El Qara formations (Oligocene) at this transition. The El Qara Formation is a new rock unit proposed herein for the Oligocene (Rupelian age) in the first time. Several episodes of volcanic activity occurred in Egypt during the Cenozoic. Mid Tertiary volcanicity was widespread and a number of successive volcanic pulses are starting in the late Eocene. The release of mantle CO2 from this very active volcanic episode may have in fact directly caused the warm Eocene-Oligocene greenhouse climate effect.

  17. Palaeoenvironment and Holocene land use of Djara, Western Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Kindermann, Karin; Bubenzer, Olaf; Nussbaum, Stefanie; Riemer, Heiko; Darius, Frank; Pöllath, Nadja; Smettan, Ursula

    2006-07-01

    The results of the interdisciplinary project ACACIA support the assumption of a more humid climate at Djara, on the Egyptian Limestone Plateau, which is a hyper-arid desert today, during the early and mid-Holocene. The ancient plant and animal inventories give new impetus for the suggestion of an interfingering of two climatic regimes, the winter rains from the north and west and the summer monsoonal rains from the south, on the latitude of Djara. A playa sediment sequence, the composition of plant and animal taxa as well as the reconstructed settlement patterns indicate a semi-arid climate with alternating more humid and drier conditions. The concentration of prehistoric sites in the Djara depression points to locally favourable conditions in contrast to the surrounding plateau surface. The widespread catchment and a distinct system of palaeochannels offered fresh water over a period of time due to the run-off from the plateau surface after rain events. Although the ecological conditions were better during the Holocene humid phase than they are today, a sedentary way of life was improbable. The hydrological constraints require altogether highly mobile subsistence strategies. Shells of the Nile bivalve Aspatharia sp. ( Spathopsis sp.) give evidence for contacts between Djara and the Nile Valley, which remains beside the Egyptian oases an important retreat area with perennially available water. The decrease of radiocarbon dates and related archaeological sites around 6300 BP (c. 5300 cal BC) indicate the depopulation of the Djara region as a consequence of the drying trend. While the drop off of the 14C-dates can also be observed in other desert research areas of the ACACIA-project, we date the end of the Holocene humid phase about 300 years earlier than previously suggested.

  18. Electric fabric of Cretaceous clastic rocks in Abu Gharadig basin, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Nabawy, Bassem S.; ElHariri, Tarek Y. M.

    2008-09-01

    Measuring the petrophysical properties of sedimentary rocks in three-dimensions (3-D) has a high priority for interpretation of their physical behaviour. The present work attempts to study the 3-D electric behaviour of the Upper Cretaceous sandstones and clayey sandstones in the Abu Gharadig basin, Egypt. These rocks belong to the Betty, Bahariya, and Abu Roash Formations. The apparent electrical resistivity ( Ro) was measured in three perpendicular directions, one normal to the bedding plane along Z-axis, and the other two directions parallel to the bedding plane and normal to each other, along X-axis and Y-axis. The electrical resistivity ( Ro) was also studied at three NaCl-saline concentrations of Rw = 0.53, 0.13, and 0.07 Ω m in ambient conditions, using A-C bridge at 1 kHz. It is proposed that, processing and matching the electric data in 3-D as ellipsoids instead of in 2-D, has led to the electric fabric concept. It is a combination of electric foliation ( F) and electric lineation ( L). Statistical analyses of measured electrical resistivity reveal that the electric fabric at the second brine concentration should be taken into consideration to avoid the effect of clay content. The electric lineation and foliation of the studied sandstones and clayey sandstones at the second concentration are mostly small (1.1-1.5) to moderate (1.5-2.5), with few sandstone samples having high (2.5-5.0) to very high foliation (5.0-7.5), whereas the electric anisotropy values for these samples are small to moderate (1.1-2.5). This fabric is contributed mainly from their electric foliation, indicating some load pressure compaction that led to small to moderate anisotropic grains and flow paths/network pore spaces.

  19. Preservation of primary structures and organic matter in Pleistocene spring carbonates, Western Desert, Egypt: Relationship to macroscopic texture and age.

    NASA Astrophysics Data System (ADS)

    Pohlman, E.; Smith, J. R.

    2005-12-01

    Spring-deposited carbonates (tufas) along the flanks of the Libyan Escarpment in Dakhleh and Kharga Oasis record relatively humid conditions which prevailed in the Egyptian Sahara periodically throughout the Pleistocene. Previous work, particularly Nicoll et al.(1999), has suggested the Western Desert tufas, though certainly displaying evidence of secondary cementation by sparry calcite, aggrading neomorphism, etc. do in many instances preserve primary features, particularly organosedimentary lamination, and a clotted microbial texture. In order to facilitate field-based selection of suitable, unaltered samples for geochemical analysis, we undertook a petrographic examination of tufa samples in order to determine whether certain macroscopic features (e.g., color, porosity, presence of detrital iron oxides, preservation of visible plant casts) could be quantitatively correlated to the degree of diagenesis present in thin sections as indicated by percent calcite spar. We also determined total organic content through peroxide digestion, as younger samples (determined by U-series dating and by geomorphic context) qualitatively appeared to contain both more casts of botanical remains, and better defined microbial textures. Older and more altered tufas also generally had heavier (less organically-influenced) carbon isotopic signatures, further suggesting a relationship between diagenesis, organic content, and age. Petrographic analysis included descriptions of sample texture, spatial relationship of textural elements (e.g., pores, plant casts, detrital material), and frequency of biological inclusions or casts. Point counts were performed to estimate sample mineralogy and porosity. Tufas are predominantly micritic calcite, with little (generally <2%) sparry calcite. Porosity may be as great as 46%. Most samples examined displayed some evidence of primary (generally microbial) textures. The expected relationship between porosity and diagenetic alteration, however, was not

  20. Cosmogenic, radiogenic, and stable isotopic constraints on groundwater residence time in the nubian aquifer, western desert of egypt

    SciTech Connect

    Patterson, Leslie J.; Sturchio, Neil C.; Kennedy, B.Mack; van Soest, Matthias C.; Sultan, Mohamed; Lu, Zheng-Tian; Lehmann, Bernhard; Purtschert, Roland; El Alfy, Zeinhom; El Kaliouby, Baher; Dawood, Yehia; Abdallah, Ali

    2004-06-01

    Measurements of radiochlorine ({sup 36}Cl), radiogenic noble gases ({sup 4}He and {sup 40}Ar), and stable chlorine isotope ratios were obtained to assess the residence time of groundwater in the Nubian Aquifer of the Western Desert of Egypt. Measured {sup 36}Cl/Cl ratios yield apparent residence times from {approx}0.2 to 1.2 x 10{sup 6} years in the deep (600-1200 m) groundwater (assuming constant Cl) and {le} 0.16 x 10{sup 6} years in the shallow (<600 m) groundwater. Values of {delta}{sup 37}Cl in the groundwater strengthen the application of the {sup 36}Cl dating method by constraining Cl sources and identifying groundwater mixing. Dissolved gases were measured in some of the deep groundwater samples. Measured {sup 4}He concentrations indicate accumulation of radiogenic {sup 4}He that is qualitatively consistent with the age progression indicated by the {sup 36}Cl/Cl ratios, but the flux of external {sup 4}He from the underlying crust has not been quantified and is not constant throughout the aquifer. Concentrations of {sup 40}Ar range from 3.3 to 6.7 x 10{sup -4} ccSTP/g and indicate excess air incorporation at recharge. Measured {sup 40}Ar/{sup 36}Ar ratios do not exceed the atmospheric ratio. A two-dimensional numerical hydrodynamic transect of the aquifer was modeled from the area of the Uweinat Uplift to the northern Bahariya Oasis. Predicted groundwater velocities in the deep portion of the aquifer are 0.5-3.5 m/yr with groundwater residence times up to 9 x 10{sup 5} years; residence times up to 1.3 x 10{sup 6} years are predicted in the confining shale. Aquifer properties are estimated by using the model to fit the measured {sup 36}Cl/Cl ratios. Under these conditions, hydrodynamic residence times are within about 30 percent of those calculated from {sup 36}Cl when mixing of Cl{sup -} is accounted for in the highest-Cl{sup -} deep groundwaters. By mutually calibrating multiple methods (hydrodynamic, {sup 36}Cl, and {sup 4}He), a consistent picture of the

  1. Thickness variation of the sedimentary cover in the South Western Desert of Egypt as deduced from Bouguer gravity and drill-hole data using neural network method

    NASA Astrophysics Data System (ADS)

    Abdel Zaher, M.; Senosy, M. M.; Youssef, M. M.; Ehara, S.

    2009-06-01

    The Bouguer anomaly map of scale 1:500,000 and the lithological logs of more than 120 deep wells distributed in the Southern part of Western Desert of Egypt were used to determine the thickness of the sedimentary cover containing the main sandstone water formation. The predominant structures affecting both the basement rock and the sedimentary cover were also studied. Gravity stripping approach was applied to separate density anomalies within the sedimentary fill from the influence of deeper levels in the crystalline crust. The study indicated that the surface of the basement rock is highly rugged and mostly controlled by structures causing variation of the sedimentary cover thickness from location to other all over the area. Isopach maps were constructed based on the Artificial Neural Network (ANN) model which is considered a best method for that operation. The maximum thickness of sandstone formations is recorded at west Oweinat, southwest of Aswan, Dakhla oasis and west of Qena town. As this formation is the main water aquifer in the study area, therefore these locations are characterized by the presence of huge amount of ground water. Accordingly, these areas must be taking the priority in the programs of sustainable development in southern Egypt.

  2. The Climate and its Impacts on deterioration and weathering rate of EI-Nadura Temple in El- Kharga Oasis, Western Desert of Egypt.

    NASA Astrophysics Data System (ADS)

    Ismael, Hossam

    2015-04-01

    Undoubtedly, El-Kharga Oasis monumental sites are considered an important part of our world's cultural heritage in the South Western Desert of Egypt. These sites are scattered on the floor of the oasis representing ancient civilizations. The Roman stone monuments in Kharga represent cultural heritage of an outstanding universal value. Such those monuments have suffered weathering deterioration. There are various elements which affect the weathering process of stone monuments: climate conditions, shapes of cultural heritages, exposed time periods, terrains, and vegetation around them, etc. Among these, climate conditions are the most significant factor affecting the deterioration of Archeological sites in Egypt. El- Kharga Oasis belongs administratively to the New Valley Governorate. It is located in the southern part of the western desert of Egypt, lies between latitudes 22°30'14" and 26°00'00" N, and between 30°27'00" and 30°47'00" E. The area of El Kharga Oasis covers about 7500 square kilometers. Pilot studies were carried out on the EI-Nadura Temple, composed of sandstones originating from the great sand sea. The major objective of this study is to monitor and measure the weathering features and the weathering rate affecting the building stones forming El-Nadora Roman building rocks in cubic cm. To achieve these aims, the present study used analysis of climatic data such as annual and seasonal solar radiation, Monthly average number of hours of sunshine, maximum and minimum air temperatures, wind speed, which have obtained from actual field measurements and data Meteorological Authority of El-Kharga station for the period 1977 to 2010 (33 years), and from the period 1941-2050 (110 years) as a long term of temperature data. Several samples were collected and examined by polarizing microscopy (PLM), X-ray diffraction analysis (XRD) and scanning electron microscopy equipped with an energy dispersive X-ray analysis system (SEM-EDX). The results were in

  3. Comment on "Danian/Selandian unconformity in the central and southern Western Desert of Egypt" by S. Farouk and A. El-Sorogy [J. Afr. Earth Sci. 103 (2015) 42-53

    NASA Astrophysics Data System (ADS)

    Ruban, Dmitry A.; Zorina, Svetlana O.

    2016-06-01

    In their recent paper, Farouk and El-Sorogy (2015) present a reconstruction of the Danian-Selandian relative sea-level changes for the Western Desert of Egypt and an interpretation of eustatic versus tectonic controls on the latter. However, the relative sea-level changes should be distinguished from the shoreline shifts (also for the purposes of inter-regional comparisons). From three alternative global curves, two confirm the authors' conclusions, although it is questionable whether these curves are suitable for the purposes of such an analysis. It cannot be excluded that the relative sea-level fall in the late Danian was caused by the same regional tectonic uplift that resulted in the hiatus at the Danian/Selandian boundary. More research (including quantitative palaeobathymetric modelling) is necessary to understand the relative importance of the eustatic and tectonic controls on the sea-level changes established in the Western Desert of Egypt.

  4. Hydrogeological aspects and environmental concerns of the New Valley Project, Western Desert, Egypt, with special emphasis on the southern area

    SciTech Connect

    Assaad, F.A. )

    1988-12-01

    The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical, and petrographical studies were conducted on four wells south of Beris Oasis. The Nubian sandstones in the area south of Beris Oasis contain hematitic stains and/or fine granular authigenic hematite, thin laminae of brown ferruginous quartzite is also recorded denoting oxidizing conditions in the basin of deposition. Thin streaks of carbonaceous shales are met with in different depths to the south of Beris area, may be taken to denote oscillations in the sea level and accordingly its depths, and are responsible for the change in the oxidation-reduction potential during the deposition of the corresponding beds. Petrographic examination of a thin section of the subsurface Nubia sandstones in the South of Beris Oasis showed that the lithified rocks fail into three types depending on the nature of cement being, silicious or ferruginous, and on the amount of primary matrix, which at present is reorganized into iron oxides, microquartz, and muscovite flakes, thus reaching the phyllomorphic stage of diagenesis. Rounding of the quartz grains shows that transportation had a minor effect on the grain morphology and favor a fluviatile transporting agent.

  5. Jurassic-Cretaceous palynomorphs, palynofacies, and petroleum potential of the Sharib-1X and Ghoroud-1X wells, north Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Zobaa, Mohamed K.; El Beialy, Salah Y.; El-Sheikh, Hassan A.; El Beshtawy, Mohamed K.

    2013-02-01

    Palynomorph and palynofacies analyses have been performed on 93 cutting samples from the Jurassic Masajid Formation and Cretaceous Alam El Bueib, Alamein, Dahab, Kharita, and Bahariya formations in the Sharib-1X and Ghoroud-1X wells, north Western Desert, Egypt. Two palynological biozones are proposed for the studied interval of the Sharib-1X well: the Systematophora penicillata-Escharisphaeridia pocockii Assemblage Zone (Middle to Late Jurassic) and the Cretacaeiporites densimurus-Elateroplicites africaensis-Reyrea polymorpha Assemblage Zone (mid-Cretaceous: late Albian to early Cenomanian). Spore coloration and visual kerogen analysis are used to assess the thermal maturation and source rock potential. Mature oil prone to overmature gas prone source rocks occur in the studied interval of the Sharib-1X well, whereas highly mature to overmature gas prone source rocks occur in the studied interval of the Ghoroud-1X well. Palynofacies and palynomorph assemblages in both wells reflect shallow marine conditions throughout the Jurassic and the late Albian and early Cenomanian. During these times, warm and dry climatic conditions prevailed. The Cretaceous palynomorph assemblages of the Sharib-IX well correlate with the Albian-Cenomanian Elaterates Province of Herngreen et al. (1996).

  6. The bivalve Placuna (Indoplacuna) miocenica from the Middle Miocene of Siwa Oasis, Western Desert of Egypt: Systematic paleontology, paleoecology, and taphonomic implications

    NASA Astrophysics Data System (ADS)

    El-Sabbagh, Ahmed M.; El Hedeny, Magdy M.; Rashwan, Mohammed A.; Abdel Aal, Abdel Aal A.

    2016-04-01

    The present study investigated the epifaunal, free lying bivalve Placuna (Indoplacuna) miocenica (Fuchs, 1883) encountered in the Middle Miocene Marmarica Formation of Siwa Oasis, Western Desert, Egypt, in terms of systematic paleontology, paleoecology and taphonomy. Well to moderately preserved shells of this species were collected from three sections. They have been found embedded in sandy, marly and chalky limestones. Although they are extremely thin and fragile, they occurred as complete disarticulated and articulated valves. Specimens of P. (I.) miocenica are highly accumulated in the north Siwa section forming a coquinoid band (30 cm thick). In addition, they are generally distributed sporadically in different stratigraphic levels within the three studied sequences. Taphonomic observations indicated that these shells were affected by encrustation, bioerosion, disarticulation, fragmentation and abrasion. Moreover, valves of this species suffered minor chipping along their fragile margins. The occurrence of the studied species associated with oysters and other benthic faunal assemblages within carbonate sediments revealed shallow, low energy, warm and intertidal environments with periods of relatively agitated conditions.

  7. Characterization of magnetic spherical fractions in sand deposits for interpretation of environmental change around the El- Zayyan temple, Kharga Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Watanabe, Makiko; Koizumi, Natsuko; Kato, Sayuri; Kikuchi, Ryohei; Kamei, Hiroyuki

    2014-05-01

    Desertification in North Africa has rapidly advanced over the last 6,000 years. Such environmental changes began in the Early Dynastic Period of Egypt (4200 - 3150 BC), and the occupation of Achaemenid Persian and Roman cultures in Egypt occurred under even drier climates. Kharga is the largest oasis of the five oases, located in the western desert of Egypt that contains a treasure trove of archaeological resources. This oasis has been highlighted to promote resource exploration and development of archaeological tourism since the 1980's. The El-Zayyan temple is located 27 km south of the central Kharga oasis. Zayyan was once called 'Tchonemyris', which has connection with the means of 'huge well' in Greek. Although major portions of the temple were rebuilt in 140 AD during the rule of the Roman Emperor Antoninus Pius, this temple is considered to be originally built in the Ptolemaic period (4c-1c BC). It is likely that the area had a sufficient water supply in the past as the El-Zayyan temple stands at the lowest point (-18 m a.s.l.) in the Kharga oasis. Furthermore, the El-Ghueita temple that stands on a hill top at 68.5 m a.s.l., 4 km northward from the El-Zayyan temple, has given name that means 'beautiful garden' in Greek. From these facts, we can imagine that the past landscape of this area contained green surroundings. The El-Ghueita temple was well known as a production centre of high quality wine since the mid-Dynastic age (2050 -1786 BC). As this area is currently arid, it is expected that there were irrigation facilities to maintain the vast farm land during the ancient period. To deepen our knowledge of how people developed their technologies and conducted their life within the natural environment of a drastic drying period, understanding the process of environmental change on a region scale is necessary. The aim of this study was to extract proxies from sand deposits in the western desert area to estimate the change in the environment. We examined the

  8. Geophysical contribution to evaluate the subsurface structural setting using magnetic and geothermal data in El-Bahariya Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El All, Esmat Abd; Khalil, Ahmed; Rabeh, Taha; Osman, Salah

    2015-12-01

    The future development of agriculture, industry, and civil activity is planned to be in the Western Desert, Egypt. El-Bahariya Oasis is located in the heart of the Western Desert at a distance of about 370 km to the southwest of Cairo. The area under investigation is located between latitudes 28°06‧N & 28°16‧N and longitudes 28°54‧E & 29°04. The Bahariya depression comprises a total area of approximately 2250 km2. The main target of the present study is to delineate the shallow and deep subsurface structures of the study area. To achieve this, two geophysical methods (magnetic and geothermal) have been used. A detailed land magnetic survey has been acquired. Fifty three land magnetic stations have been measured in a mesh like area with 500 m spacing interval. The necessary corrections concerning daily variation, the regional gradient and time variations have been applied. Then, the total magnetic intensity anomaly map (TMI) has been constructed and reduced to the pole magnetic map (RTP). The Euler deconvolution has been applied to the TMI anomaly data as well as the analytical signal technique. Also, the magnetic interpretation has been carried out using the high-pass filtering technique and spectral frequency analysis. The analysis of the magnetic data shows that the dominant tectonic trends are NW-SE and E-W. The results show that, the average calculated depth ranges between 0.1 km and 0.32 km, while the depth to the basement intrusion is 0.4 km, below the measuring level. The geothermal studies in EL Bahariya-Oasis comprise subsurface temperature contour map which illustrates that the study area has geothermal groundwater reservoirs. The measurements of the geothermal properties for measured rock samples show that the rocks of the study area have moderate values of geothermal properties. This may be due to the seasonal variation in soil temperatures. These soil thermal properties depend on soil porosity and moisture content.

  9. Substance geology of the western desert in Egypt and Sudan revealed by Shuttle Imaging Radar (SIR-A)

    NASA Technical Reports Server (NTRS)

    Breed, C. S.; Schaber, G. G.; Mccauley, J. F.; Grolier, M. J.; Haynes, C. V.; Elachi, C.; Blom, R.; Issawi, B.; Mchugh, W. P.

    1983-01-01

    A correlation of known archaeologic sites with the mapped locations of the streamcourses is expected and may lead to new interpretations of early human history in the Sahara. The valley networks, faults, and other subjacent bedrock features mapped on the SIR-A images are promising areas for ground water and mineral exploration. Additionally, the analogies between the interplay of wind and running water in the geologic history of the Sahara and of Mars are strengthened by the SIR-A discoveries of relict drainage systems beneath the eolian veneer of Egypt and Sudan.

  10. A shell concentration of the Middle Miocene Crassostrea gryphoides (Schlotheim, 1813) from Siwa Oasis, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El-Sabbagh, Ahmed M.; El Hedeny, Magdy M.

    2016-08-01

    A concentration of heavy, thick-shelled, large-sized, and elongated population of the oyster Crassostrea gryphoides (Schlotheim, 1813) was recorded in shallow-marine deposits of the basal Oasis Member of the Middle Miocene Marmarica Formation exposed at Siwa Oasis, Egypt. The oyster assemblage is resedimented as a lens-shaped bank up to 80-100 cm thick and about 220 m long. Crassostrea gryphoides specimens are embedded in a yellowish green, soft marl matrix. This is the first documented occurrence of this lens at Siwa Oasis. The lensoid structure is bounded by a lower marl and an upper shale beds of about 2 m and 1.5 m thick, respectively. Assemblage within this lens is characterized by extreme variations of Crassostrea gryphoides, forming an almost monotypic assemblage. The shell packing was dense (shell percentages higher than 75%) at the base and the center of the lens, whereas it exhibits loose packing at the top and right and left sides of the lens (shell percentage less than 15%). Valves are poorly sorted and randomly orientated (both in surface and cross section views). Encrustation and bioerosion have observed on both sides of the left and right valves. The relatively limited varieties of encrusters together with moderate frequency of borings indicate moderate to high sedimentation rate. On the other hand, the low abundance of fragmented and abraded shells indicates good preservation and minimal transport. The studied lens concentration is interpreted as proximal tempestites assemblage.

  11. The Dakhleh Glass: Product of an impact airburst or cratering event in the Western Desert of Egypt?

    NASA Astrophysics Data System (ADS)

    Osinski, G. R.; Kieniewicz, J.; Smith, J. R.; Boslough, M. B. E.; Eccleston, M.; Schwarcz, H. P.; Kleindienst, M. R.; Haldemann, A. F. C.; Churcher, C. S.

    2008-12-01

    Impact cratering is a ubiquitous geological process on the terrestrial planets. Meteorite impact craters are the most visible product of impact events, but there is a growing recognition that large aerial bursts or airbursts should occur relatively frequently throughout geological time. In this contribution, we report on an unusual impact glass—the Dakhleh Glass (DG)—which is distributed over an area of ~400 km2 of the Dakhleh Oasis, Egypt. This region preserves a rich history of habitation stretching back to over 400,000 years before the emergence of Homo sapiens. We report on observations made during recent fieldwork and subsequent analytical analyses that strengthen previous suggestions that the DG formed during an impact event. The wide distribution and large size of DG specimens (up to ~50 cm across), the chemistry (e.g., CaO and Al2O3 contents up to ~25 and ~18 wt%, respectively), the presence of lechatelierite and burnt sediments, and the inclusion of clasts and spherules in the DG is inconsistent with known terrestrial processes of glass formation. The age and other textural characteristics rule out a human origin. Instead, we draw upon recent numerical modeling of airbursts to suggest that the properties of DG, coupled with the absence of a confirmed crater, can best be explained by melting of surficial sediments as a result of a large airburst event. We suggest that glass produced by such events should, therefore, be more common in the rock record than impact craters, assuming that the glass formed in a suitable preserving environment.

  12. Tectonic and provenance history of the Neotethyan margin in NE Africa recorded by detrital zircon (U-Th)/He thermochronometry from a borehole in the Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Stockli, D.; Glauser, T.; Bosworth, W.; Maher, T.; Clare, A.

    2009-04-01

    The subsurface of the Western Desert of Egypt contains multiple stacked sedimentary basin deposits separated by major unconformities reflecting the long-lived tectonic evolution of the Neotethyan continental margin in eastern North Africa. In this study, zircon (U/Th)/He (ZHe) data were collected from cuttings from a ~15000 ft borehole that penetrated Tertiary and Cretaceous strata and a major erosional unconformity at 13000 ft that juxtaposes Cretaceous and Cambro-Ordovician strata. A total of 56 samples spanning the borehole from 750-15400 ft yielded >200 single-grain ZHe ages in order to elucidate the thermal evolution of the borehole and constrain the thermal history of detrital provenance. ZHe ages above the unconformity are significantly older than the depositional age, suggesting detrital ZHe ages that were not reset subsequent to deposition. ZHe ages from Cambro-Ordovician strata below the unconformity are substantially younger than the minimum depositional age suggesting major cooling and resetting of zircon (>200C) during the Hercynian orogeny. In detail, ZHe ages form Cretaceous strata above the unconformity show the following trends. (1) ZHe ages from 6000-9000 ft (Aptian-Early Cenomanian) are characterized by a ZHe age peak at ~450 Ma and a minor Albian peak, (2) samples from 9000-12000 ft (Late Hauterivian-Barremian) show two major detrital ZHe age peaks at ~450 and 350 Ma, while (3) samples from 12000-13000 ft (Early Hauterivian) exhibit three dominant ZHe age components at ~450 Ma, 350 Ma, and 170-200 Ma. Additional cuttings from an offset containing complete stratigraphy yielded ZHe ages that mainly represent a strong Hercynian input as well as Late Triassic and Early Jurassic components of Tethyan related input. These ZHe age peaks display provenance characteristics typical for cooling signatures of rocks from the eroding Arabian-Nubian Shield, a North-African Hercynian source, and eroded material from exhumed fault blocks along the Triassic

  13. Pseudospherulitic fibrous calcite from the Quaternary shallow lacustrine carbonates of the Farafra Oasis, Western Desert, Egypt: A primary precipitate with possible bacterial influence

    NASA Astrophysics Data System (ADS)

    Wanas, H. A.

    2012-04-01

    Pseudospherulitic fibrous calcite (PFC) has been found as a major constituent (85-90%) within thin massive limestone beds of the Quaternary mudflat-shallow lacustrine facies association (1.5-2 m thick) that forms part of combined facies associations of the Quaternary clastic-carbonate unit (25-30 m thick) at Bir-Karawein area in the Farafra Oasis, Western Desert, Egypt. The thin massive limestone beds (2-5 cm thick) are devoid of pedogenic features and marine fossils. They form a rhythmic cyclic succession with thin massive mudrocks (5-10 cm thick). The mudflat-shallow lacustrine facies association herein occurs within a depositional sequence of distal alluvial-floodplain (6-12 m thick) and palustrine (1.5-4.5 m thick) facies associations. The PFC is a composed of loosely packed rounded to sub-rounded single low-Mg-calcite crystals (150-250 μm-sized) with intracrystalline fibrous microfabric marked by fibers (150-250 μm long and 10-20 μm wide) radiating from the center of the individual crystals and displaying irregular internal growth with lobate pattern. The PFC crystals show non-planar to highly irregular intercrystalline boundaries. Under SEM, the individual crystal fibers group of PFC form ellipsoid to sub-globular bodies. Each PFC crystal exhibits successive zones of thick non-luminescence and thin brightly orange to dull luminescence. The matrix (10-15%) between the PFC crystals is mainly a honeycomb-like smectite. The PFC is postulated to be a primary precipitate. This concept is reached because the PFC: (i) does not display the criteria of typical Microcodium structures, root-calcification, speleothem structures, calcite spherulites of laminar calcretes, and calcitization of precursor dolomite or aragonite, (ii) possesses homogenous compositional and textural characteristics, and (iii) occurs within limestone beds that lie in between impermeable massive mudrock beds that dampen diagenesis. A role for possible bacterial contribution in crystallization of

  14. Application of multivariate statistical analyses in the interpretation of geochemical behaviour of uranium in phosphatic rocks in the Red Sea, Nile Valley and Western Desert, Egypt.

    PubMed

    El-Arabi, Abd El-Gabar M; Khalifa, Ibrahim H

    2002-01-01

    Factor and cluster analyses as well as the Pearson correlation coefficient have been applied to geochemical data obtained from phosphorite and phosphatic rocks of Duwi Formation exposed at the Red Sea coast. Nile Valley and Western Desert. Sixty-six samples from a total of 71 collected samples were analysed for SiO2, TiO2, Al203, Fe2O3, CaO, MgO, Na2O, K2O, P2O5, Sr, U and Pb by XRF and their mineral constituents were determined by the use of XRD techniques. In addition, the natural radioactivity of the phosphatic samples due to their uranium, thorium and potassium contents was measured by gamma-spectrometry. The uranium content in the phosphate rocks with P2O5 > 15% (average of 106.6 ppm) is higher than in rocks with P2O5 < 15% (average of 35.5 ppm). Uranium distribution is essentially controlled by the variations of P2O5 and CaO, whereas it is not related to changes in SiO2, TiO2, Al2O3, Fe2O3, MgO, Na2O and K2O concentrations.-Factor analysis and the Pearson correlation coefficient revealed that uranium belaves geochemically in different ways in the phosphatic sediments and phosphorites in the Red Sea, Nile Valley and Western Desert. In the Red Sea and Western Desert phosphorites, uranium occurs mainly in oxidized U6+ state where it seems to be fixed by the phosphate ion, forming secondary uranium phosphate minerals such as phosphuranylite. In the Nile Valley phosphorites, ionic substitution of Ca2+ by U4 is the main controlling factor in the concentration of uranium in phosphate rocks. Moreover, fixation of U6- by phosphate ion and adsorption of uranium on phosphate minerals play subordinate roles. PMID:12066979

  15. Fusulinid marble from Wadi Heimur area, Southeastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Ahmed, Abd-Elmohsen A.

    The discovery of Fusulina in the graphitic marble of Wadi Heimur area, located east of Lake Nasser has verified the Carboniferous age previously given by Ahmed and Mahmoud (1984) and Ahmed (1987) for the foraminiferal marble bands of the folded eugeosynclinal sequence outcropping in the Eastern Desert of Egypt.

  16. Another approaching storm on the desert. Egypt.

    PubMed

    Werner, D

    1991-01-01

    Examining Egypt's health care crisis, this article discusses the political factors that have led to such a state. Although Egypt possesses considerable resources and receives vast amounts of US foreign aid, the health status of its people is poor. Infant mortality rate stands at 67/1000 live births; the poor nutritional status of children has not improved over the past 10 years; 1/3 of all children are moderately to severely stunted in growth. The author attributes these woeful conditions to the country's political and economic policies. At one time or another, Egypt has allied itself with USSR or the US, and has generally retained only the worst features of socialism and the free market. While operating as a police state, Egypt has moved towards a free market that has led to the concentration of wealth. The author points out how medical care and medical school reflect the political and economic system. The government guarantees free health care for all and a job to all medical school graduates. But doctors now have to wait 7 years to obtain a post. Many have begun practicing private medicine, and many have become corrupt. The author also singles out the country's diarrhea control program as an indication of the impending health care disaster. Though hailed as high successful, the cost has been exceptionally high, and USAID funding will soon cease. Furthermore, mothers have not been taught self-reliance, but have been made to depend on commercially produced oral rehydration packets. Despite the severity of the social problems, Egypt's security forces have so far succeeded in suppressing popular opposition. But the author does detect hopeful signs in the many active progressive groups, and in particular, in the great social accomplishments of the governor of the providence of Ismailia. PMID:12159260

  17. Hydrologic and climatic implications of stable isotope and minor element analyses of authigenic calcite silts and gastropod shells from a mid-Pleistocene pluvial lake, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Kieniewicz, Johanna M.; Smith, Jennifer R.

    2007-11-01

    Authigenic calcite silts at Wadi Midauwara in Kharga Oasis, Egypt, indicate the prolonged presence of surface water during the Marine Isotope Stage 5e pluvial phase recognized across North Africa. Exposed over an area of ˜ 4.25 km 2, these silts record the ponding of water derived from springs along the Libyan Plateau escarpment and from surface drainage. The δ 18O values of these lacustrine carbonates (- 11.3‰ to - 8.0‰ PDB), are too high to reflect equilibrium precipitation with Nubian aquifer water or water of an exclusively Atlantic origin. Mg/Ca and Sr/Ca of the silts have a modest negative covariance with silt δ 18O values, suggesting that the water may have experienced the shortest residence time in local aquifers when the water δ 18O values were highest. Furthermore, intra-shell δ 18O, Sr/Ca, and Ba/Ca analyses of the freshwater gastropod Melanoides tuberculata are consistent with a perennially fresh water source, suggesting that strong evaporative effects expected in a monsoonal climate did not occur, or that dry season spring flow was of sufficient magnitude to mute the effects of evaporation. The input of a second, isotopically heavier water source to aquifers, possibly Indian Ocean monsoonal rain, could explain the observed trends in δ 18O and minor element ratios.

  18. Epidemiology and clinical presentation of stroke in Upper Egypt (desert area)

    PubMed Central

    El Tallawy, Hamdy N; Farghaly, Wafaa M; Badry, Reda; Hamdy, Nermin A; Shehata, Ghaydaa A; Rageh, Tarek A; Metwally, Nabil A; Hassan, Enas M; Elsayed, Sayed S; Yehia, Mohamed A; Soliman, Wael T

    2015-01-01

    Background Stroke is a common cause of morbidity and mortality worldwide. Four out of five strokes occur in the low- and middle-income countries. This study aims to find lifetime prevalence of stroke in Upper Egypt and to identify clinical presentations and possible risk factors of stroke in this population. Methods This is a door-to-door (every door) study conducted on all inhabitants in Al Kharga district (representative of western desert) and Al Quseir city (representative of eastern desert). The study was conducted in two stages, and every stage consisted of three phases (screening, diagnostic, and investigatory). Results The total lifetime prevalence of stroke was 8.5/1,000 in the population aged 20 years and more. It increased with advancing age and was higher among males than females among all age groups except in the childbearing period (20 years to <40 years of age). Lifetime prevalence of ischemic stroke (7.2/1,000) was higher than hemorrhagic stroke (1.1/1,000). Hemiparesis and hemiplegia were the commonest presentation of stroke. Headache, vomiting, and vertigo were found to be significantly more common accompaniments of hemorrhagic stroke. The most common risk factor was hypertension, followed by hyperlipidemia and diabetes mellitus. Conclusion The total lifetime prevalence of stroke in the population aged 20 years and more in Upper Egypt (desert area) lies within the range that is recorded in developing countries. Clinical presentation and risk factors are similar to those recorded from developing and developed countries. PMID:26346729

  19. Basin deconstruction-construction: Seeking thermal-tectonic consistency through the integration of geochemical thermal indicators and seismic fault mechanical stratigraphy ​- Example from Faras Field, North Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Pigott, John D.; Abouelresh, Mohamed O.

    2016-02-01

    To construct a model of a sedimentary basin's thermal tectonic history is first to deconstruct it: taking apart its geological elements, searching for its initial conditions, and then to reassemble the elements in the temporal order that the basin is assumed to have evolved. Two inherent difficulties implicit to the analysis are that most organic thermal indicators are cumulative, irreversible and a function of both temperature and time and the non-uniqueness of crustal strain histories which complicates tectonic interpretations. If the initial conditions (e.g. starting maturity of the reactants and initial crustal temperature) can be specified and the boundary conditions incrementally designated from changes in the lithospheric heat engine owing to stratigraphic structural constraints, then the number of pathways for the temporal evolution of a basin is greatly reduced. For this investigation, model input uncertainties are reduced through seeking a solution that iteratively integrates the geologically constrained tectonic subsidence, geochemically constrained thermal indicators, and geophysically constrained fault mechanical stratigraphy. The Faras oilfield in the Abu Gharadig Basin, North Western Desert, Egypt, provides an investigative example of such a basin's deconstructive procedure. Multiple episodes of crustal extension and shortening are apparent in the tectonic subsidence analyses which are constrained from the fault mechanical stratigraphy interpreted from reflection seismic profiles. The model was iterated with different thermal boundary conditions until outputs best fit the geochemical observations. In so doing, the thermal iterations demonstrate that general relationship that basin heat flow increases decrease vertical model maturity gradients, increases in surface temperatures shift vertical maturity gradients linearly to higher values, increases in sediment conductivities lower vertical maturities with depth, and the addition of "ghost" layers

  20. Paleozoic and Mesozoic stratigraphy and oil potential of Western Desert

    SciTech Connect

    Khalil, N.A.; Young, D.; Nairn, A.E.M.

    1983-03-01

    The depocenter of the Paleozoic basin in western Egypt lies in the northwestern part of the Western Desert. The depositional axis of the basin, where thicknesses in excess of 2800 m (9200 ft) have been recorded, has a northwesterly trend to the vicinity of the Siwa Oasis. A less well-defined shallower basin with a northerly trend lies to the southwest. Farther east, a possible Paleozoic basin lies in the Abu Gharadig area where 1300 m (4265 ft) of sediments were drilled. Following the deposition of the Paleozoic section, there was a marked hiatus; the time of Hercynian movements for Permian and Triassic beds is absent. Uplift and the presence of volcanics dated in Permian-Carboniferous time are indicative of Hercynian tectonic activity. Further tectonic uplift accompanied by faulting and marine regression is dated from late Kimmeridgian time to the beginning of the Cretaceous, when transgression began once again. The dominant feature, new in the Western Desert, was the development of an east-west extensional basin, the Abu Gharadig basin, in Cretaceous time. The trough became less distinctive in Cenozoic times when a further trough, the Tiba basin, developed north of the ridge. Production from the northern Western Desert until recently has been disappointing. Exploration results from the Paleozoic Section have yielded little, but the existence of a marine section suggests that the area northeast of Siwa still has potential. The thick deeply buried Jurassic marine sequence in the Western Desert may be the source for at least part of the production from Cretaceous horizons in the Abu Ghradig, Alamein, and Razzak oil and gas fields.

  1. Formation of Neoproterozoic metamorphic complex during oblique convergence (Eastern Desert, Egypt)

    NASA Astrophysics Data System (ADS)

    Fritz, H.; Wallbrecher, E.; Khudeir, A. A.; Abu el Ela, F.; Dallmeyer, D. R.

    1996-10-01

    Major portions of the Pan-African Orogen in the Eastern Desert of Egypt were formed by island-arc accretion in the Neoproterozoic. These areas are characterized by their lack of major crustal thickening. Metamorphic core complexes occur parallel to the strike of the Eastern Desert Orogen. These domes exhibit polyphase metamorphism and deformation in contrast to the structurally overlying nappes which include ophiolitic melanges and island-arc volcanic rocks. These nappes show northwest directed, orogen-parallel thrusting in the internal parts and west to southwest directed imbrication in the external parts of the orogen. Structures related to exhumation of the metamorphic core complexes partition into different displacement paths localized within a crustal-scale wrench corridor of the Najd fault system. Northwest trending orogen-parallel, sinistral strike-slip faults define the western and eastern margins of the domes. North and south dipping low-angle normal faults developed along the northern and southern margins of the domes and form extensional bridges between them. {40Ar}/{39Ar} ages obtained from syntectonic muscovites within the shear zones gave Neoproterozoic ages of 595.9±0.5 and 588.2±0.3 Ma. The synchronous activity of strike-slip and normal faults suggests a regional east-west shortening which was accomodated by deep-level basal decollement beneath the metamorphic core complexes and a coeval northwest-southeast, orogen-parallel extension. This extension was accompanied by intramontane molasse sedimentation and emplacement of calc-alkaline plutons. Since the rapid exhumation of gneisses in the core complexes cannot be explained by thickening of the crust, the authors favour a model which calls for enhanced heat flow along the Najd fault system which would have enabled the formation of syn-extensional plutonism and triggered the exhumation of the metamorphic core complexes. Lateral buoyancy forces were concentrated within the Najd wrench corridor and

  2. Clockwise rotation of the western Mojave Desert

    NASA Technical Reports Server (NTRS)

    Golombek, Matthew P.; Brown, Laurie L.

    1988-01-01

    A study of paleomagnetic data from Miocene volcanic rocks in the western Mojave Desert, which suggests about 25 deg of clockwise rotation, is presented. A total of 166 oriented core samples of two types of basalt were taken from 19 sites in the region. After demagnetization to 40 or 60 mT, application of structural corrections, and inversion of reversed sites, the data yielded an average direction of 51.6 deg inclination and 15.6 deg declination. When compared with the expected direction for Miocene rocks for stable North America, the direction for these Mojave rocks shows a clockwise rotation of 23.8 deg + or - 11.3 deg and a flattening of about 2.1 deg, a rotation which agrees in direction with oroclinal bending of the southern Sierra Nevada due to right-lateral shear along the western margin of North America. Most of this rotation is constrained by other paleomagnetic and strucural information to have occurred soon after the sampled basalts were deposited (about 20 Ma) and before about 16 Ma. These clockwise declination anomalies indicate that any subsequent counterclockwise rotation is small and/or compensated by previous clockwise rotation.

  3. Multisensor characterization of subsurface structures in a desert plain area in Egypt with implications for groundwater exploration

    NASA Astrophysics Data System (ADS)

    Koch, Magaly; Gaber, Ahmed; Geriesh, Mohamed H.; Zaghloul, El-Sayed; Arafat, Sayed M.; AbuBakr, Mostafa

    2013-10-01

    -Gallaba Plain of the Western Desert in Egypt.

  4. Origin and recharge rates of alluvial ground waters, Eastern Desert, Egypt.

    SciTech Connect

    Sultan, M.; Gheith, H.; Sturchio, N. C.; El Alfy, Z.; Danishwar, S.

    2002-04-12

    Stable isotope and tritium analyses of shallow ground waters in the Eastern Desert of Egypt showed that the waters were derived largely by evaporation of regional precipitation and at least partly from precipitation in the past 45 y. To estimate the ground water recharge rate, we developed an integrated hydrologic model based on satellite data, geologic maps, infiltration parameters, and spatial rainfall distribution. Modeling indicated that during a severe 1994 storm, recharge through transmission loss in Wadi El-Tarfa was 21% of the precipitation volume. From archival precipitation data, we estimate that the annual recharge rate for the El-Tarfa alluvial aquifer is 4.7 x 10{sup 6} m{sup 3}. Implications for the use of renewable ground waters in arid areas of Egypt and in neighboring countries are clear.

  5. Soil seed bank in different habitats of the Eastern Desert of Egypt

    PubMed Central

    Gomaa, Nasr H.

    2012-01-01

    The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO3, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka’s similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%). PMID:23961181

  6. Genetic Aspects of Gold Mineralization at Some Occurrences in the Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abd El Monsef, M.; Slobodník, M.; Salem, I. A.

    2012-04-01

    The Eastern Desert of Egypt is well known as a gold-mining area since ancient times, there're more than 95 gold deposits and occurrences spread the whole area covered by the basement rocks of Precambrian age. The basement rocks of the Eastern Desert of Egypt constitute the Nubian Shield that has formed a continuous part of the Arabian-Nubian Shield before the opening of Red Sea (Oligocene-Early Miocene). Commonly, the system of gold-bearing quartz veins in the Eastern Desert is clearly structural controlled related to brittle-ductile shear zones that mostly developed during late deformational stages of the evolution history for basement rocks in the Eastern Desert. This running study principally aims to contribute the mineral resource potential of the gold deposits in Egypt, so particularly Fatira, Gidami and Atalla occurrences have been involved into a comprehensive study based on field, structural, mineralogical, geochemical and genetic investigations. It is intended to better understanding for the characteristics, distribution controls, conditions and age of mineralization in relation to the age of the hosting rocks intrusion to find if there're genetic links between the gold mineralization and the evolution of the host intrusive complex. Several authors suggested that the gold mineralization was related to the intrusion of the (postorogenic) Younger granites. Other authors interpret these deposits as products of hydrothermal activity induced either by metamorphism or cooling effects of early Paleozoic magmatism or as combined metamorphic/magmatic episodes. The prime focus will be directed to the ore itself and the associated hydrothermal alteration zones based on detailed maps and well-distributed samples network and geochemical anomalies distribution. The laboratory studies included microscopic examination (reflecting and transmitting microscopy) to allow for determination of the hosting rocks types and mineralogical changes related to the gold mineralization

  7. Elemental content of feldspar from Eastern Desert, Egypt, determined by INAA and XRF.

    PubMed

    El-Taher, A

    2010-06-01

    Instrumental neutron activation analysis (INAA) and HPGe detector gamma-spectroscopy were used to determine a total of 16 elements qualitatively and quantitatively for the first time from feldspar rock samples collected from Gabel El Dubb, Eastern desert, Egypt. The elements determined are (Na, Mg, K, Sc, Ga, Cr, Fe, Co, Zn, Nb, Ba, Ce, Eu, Hf, Th and U). The samples were properly prepared together with their standard reference material and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor at a neutron flux of 7x10(11)n/cm(2)s. XRF was also used. Comparison of the results obtained by both techniques showed good agreement for such elements as K, Na, Fe, Mg, Ba and Cr. PMID:20185321

  8. Natural radioactivity and rare earth elements in feldspar samples, Central Eastern desert, Egypt.

    PubMed

    Walley El-Dine, Nadia; El-Shershaby, Amal; Afifi, Sofia; Sroor, Amany; Samir, Eman

    2011-05-01

    The pegmatite bodies of the Eastern Desert of Egypt are widely distributed especially along the Marsa-Alam-Idfu road. The Abu Dob area covers about 150km(2) of the Arabian Nubian shield at the central part of the Eastern Desert of Egypt. Most of the pegmatite is zoned; the zonation starts with milky quartz at the core followed by alkali feldspar at the margins. The feldspars vary in color from rose to milky and in composition from K-feldspar to Na-feldspar, sometimes interactions of both types are encountered. Thirteen feldspar samples were collected from different locations in the Abu Dob area for measuring the natural radioactivity of (238)U, (232)Th and (40)K using an HPGe detector. The variation in concentration of radionuclides for the area under investigation can be classified into regions of high, medium and low natural radioactivity. The average concentration in BqKg(-1) has been observed to be from 9.5 to 183675.7BqKg(-1) for (238)U, between 6.1 and 94,314.2BqKg(-1) for (232)Th and from 0 to 7894.6BqKg(-1) for (40)K. Radium equivalent activities (Ra(eq)), dose rate (D(R)) and external hazard (H(ex)) have also been determined. In the present work, the concentration of rare earth elements are measured for two feldspar samples using two techniques, Environmental Scanning Electron microscope XIL 30 ESEM, Philips, and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The existence of rare earth elements in this area are very high and can be used in different important industries. PMID:21324705

  9. Uranium-series disequilibrium dating of secondary uranium ore from the south Eastern Desert of Egypt.

    PubMed

    Dawood, Y H

    2001-12-01

    The secondary uranium ore of Um Ara mining area, south Eastern Desert of Egypt, is composed mainly of uranophane and beta-uranophane. They occur in the oxidized zone as idiomorphic crystals filling cavities and as coatings on the fracture surfaces of the alkali-feldspar and albitized granites. The activity ratios 234U/238U and 230Th/234U of the secondary uranium ore and host rocks indicate that there were two main phases of uranium mobility in recent geological time. An earlier precipitation of uranium from solutions forming the secondary ore and a subsequent mobilization resulted in adsorption of uranium to the host granitic rocks. The 230Th/234U age of secondary uranium ore varies from (50 +/- 10) to (159 +/- 69/-45) ka whereas, the age of uranium adsorption to the rocks ranges from (18 +/- 6) to (38 +/- 5) ka. The time of secondary uranium ore precipitation can be attributed to the Saharan II pluvial period which prevailed in Egypt during humid oxygen isotope climatic stage 5. The later uranium mobility and subsequent adsorption by the rocks took place during Kubbaniyan and Nabtian pluvial periods that coincided with oxygen isotope stages 3 and 1, respectively. PMID:11761113

  10. Extensional collapse along the Sevier Desert reflection, northern Sevier Desert basin, western United States

    NASA Astrophysics Data System (ADS)

    Coogan, James C.; Decelles, Peter G.

    1996-10-01

    Newly released and previously published seismic reflection data from the northern Sevier Desert basin provide a complete seismic transect between the tilted western margin of the basin and the eastern breakaway zone. When tied to well and surface age data, the transect delineates a continuum of extensional fault and basin fill geometries that developed between late Oligocene and Pleistocene time across the basin. A minimum of 18 km of top-to-the-west normal displacement is estimated across the Sevier Desert from only the most conspicuous growth geometries and offsets across listric normal faults that sole downward into the Sevier Desert reflection (SDR). The SDR clearly marks a normal fault zone beneath the entire basin, where stratal truncations are imaged for 50% of the 39 km length of the reflection east of the Cricket Mountains block. Restoration of extensional displacement along this entire 39 km fault length is necessary to reconstruct the pre-Oligocene configuration and erosion level of Sevier thrust sheets across the Sevier Desert area. The SDR normal fault zone underlies the former topographic crest of the Sevier orogenic belt, where it accommodated extensional collapse after cessation of regional contractile tectonism.

  11. Technologies Applied in the Toshka Project of Egypt

    ERIC Educational Resources Information Center

    Wahby, Wafeek S.

    2004-01-01

    The Toshka Project, located in Egypt, involves excavating a canal to carry about 380 billion ft[supercript 3] of water every year from Lake Nasser to the Toshka Depression, southwest of Aswan. This will eventually create a new valley to the River Nile in the western desert of Egypt in addition to the currently existing prehistoric river course.…

  12. Assessment of natural radioactivity and radon exhalation rate in Sannur cave, eastern desert of Egypt.

    PubMed

    Amin, Rafat M; Mansy, M; Eissa, M F; Eissa, H M; Shahin, F M

    2008-06-01

    Activity concentrations of 238U, 232Th and 40K in rocks and soil samples collected from Sannur cave, Beni Suef governorate, eastern desert of Egypt, were determined using the high-resolution gamma spectrometry technique. The results show that the concentrations of the naturally occurring radionuclides are the following: 238U ranged from 8.51 +/- 1.23 to 20.66 +/- 2.12 Bq kg(-1), 232Th ranged from 7.69 +/- 1.02 to 22.73 +/- 1.60 Bq kg(-1) and 40K ranged from 185.74 +/- 0.42 to 2084.70 +/- 23.30 Bq kg(-1). The radium equivalent activity (Raeq), the absorbed dose rate (D), and the external hazard index (Hex) were also calculated and compared to the international recommended values. The radon concentration and radon exhalation rate from the rock and soil samples were measured using the Can technique. The average value of annual effective dose for cave workers is 1.98 mSv y(-1), while for visitors it is 2.4 microSv per visit. The radon exhalation rate varies from 0.21 +/- 0.03 to 1.28 +/- 0.02 Bq m(-2) h(-1). A positive correlation has been observed between uranium content and radon exhalation rate. PMID:18495986

  13. Kocuria aegyptia sp. nov., a novel actinobacterium isolated from a saline, alkaline desert soil in Egypt.

    PubMed

    Li, Wen-Jun; Zhang, Yu-Qin; Schumann, Peter; Chen, Hua-Hong; Hozzein, Wael N; Tian, Xin-Peng; Xu, Li-Hua; Jiang, Cheng-Lin

    2006-04-01

    A coccoid, non-motile actinobacterium, designated strain YIM 70003T, was isolated from a saline, alkaline, desert-soil sample from Egypt. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism formed a distinct phyletic line within the genus Kocuria and was most closely related to Kocuria polaris DSM 14382T (98.6 % sequence similarity) and Kocuria rosea DSM 20447T (98.2 %). Chemotaxonomic data, including the Lys-Ala3 peptidoglycan type, the presence of phosphatidylglycerol and diphosphatidylglycerol as the predominant phospholipids, the presence of MK-8(H2) and MK-9(H2) as the major menaquinones, the predominance of fatty acids ai-C(15 : 0) and i-C(15 : 0) and the DNA G+C content, also supported the affiliation of the isolate to the genus Kocuria. The low DNA-DNA relatedness with K. polaris DSM 14382T (56.6 %) and K. rosea DSM 20447T (15.5 %) in combination with phenotypic data show that strain YIM 70003T should be classified as a novel species of the genus Kocuria. The name Kocuria aegyptia sp. nov. is proposed, with strain YIM 70003T (=CCTCC AA203006T = CIP 107966T = KCTC 19010T = DSM 17006T) as the type strain. PMID:16585685

  14. Palynostratigraphy of Jurrasic to Lower Cretaceous sequences from the Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Ibrahim, M. I. A.; Aboul Ela, N. M.; Kholeif, S. E.

    2001-02-01

    Well-preserved miospore assemblages are described from three deep exploration wells in the northern part of the Eastern Desert, Egypt. The composite succession in the three boreholes investigated comprises eight formations assigned to the Jurassic-Lower Cretaceous. The Jurassic/Cretaceous boundary in the subsurface of the studied area is unconformable. A stratigraphical break of varying magnitude exists in the three wells. Miospore analysis of the studied wells yielded about 186 miospore species belonging to 80 genera. Among these, 116 pteridophytic spore species are related to 53 genera, 39 gymnosperm pollen species to 15 genera and 31 angiosperm pollen species to 12 genera. Accordingly, six miospore biozones are recognised, three in the Jurassic and three in the Lower Cretaceous. In ascending stratigraphical order, these are: Classopollis/Circulina-Deltoidospora spp. Assemblage Zone (?Toarcian-Aalenian); Verrucosisporites spp.- Converrucosisporites spp.- Trilobosporites spp. Assemblage Zone (Early Bajocian-Callovian); Cicatricosisporites spp.- Contignisporites spp. Assemblage Zone (Oxfordian-Kimmeridgian); Stellatopollis spp.-? Schrankipollis spp. Assemblage Zone (Barremian); Afropollis operculatus-Brenneripollis-Tricolpites spp. Assemblage Zone (Aptian); and Crybelosporites pannuceus-Afropollis jardinus-Tricolporopollenites Assemblage Zone (Early Albian). These biozones are compared with other contemporaneous microfloral assemblages from the Northern Gondwanan Realm.

  15. The use of remote sensing and GIS for the estimation of water loss from Tushka lakes, southwestern desert, Egypt

    NASA Astrophysics Data System (ADS)

    Bastawesy, Mohamed A.; Khalaf, Fikry I.; Arafat, Sayed M.

    2008-10-01

    As a result of the spill-over of the excess water from lake Nasser, the great reservoir formed by the Aswan High Dam on the Nile, the Tushka lakes came into being within natural geological depressions in the southeastern part of the western desert of Egypt. By the end of 1998, the water of river Nile had entered Tushka depressions for the first time, once lake Nasser's water level had exceeded 178 m above the mean sea level. Intermittently, water continued to discharge into the depressions until the end of 2001 forming four lakes; however, the lakes began to shrink because of the inconsistency of flooding levels. The behavior of hydrological regime of these lakes during the period 2002-2006 was assessed using an integration of remote sensing and GIS techniques, which found that the total surface area of the lakes had diminished from 1591 km 2 to 937 km 2, and their water volumes reduced from 25.26 billion m 3 to 12.67 billion m 3. The study further revealed that the levels of the lakes surfaces had lowered by approximately 10 m over the course of those four years. This significant rate and volume of water loss can be attributed to both evaporation and infiltration. A comparison between the average annual evaporation rate at Tushka lakes and the calculated water loss revealed that most of Tushka lakes' water is lost through evaporation with a very limited amount being percolated to the ground water. Assuming that no further over flooding of the Nile will occur, these lakes will start to vanish in 2012 and disappear completely by 2020, which will result in significant environmental impacts.

  16. Paleozoic cratonal/miogeoclinal stratigraphy in the western Mojave Desert

    SciTech Connect

    Martin, M.W.; Walker, J.D. )

    1991-02-01

    Detailed mapping of metasedimentary rocks by many workers in the western Mojave Desert, California, has revealed Paleozoic lithologies of cratonal/miogeoclinal affinity. These exposures are metamorphosed, highly strained, and dismembered, and sit as roof pendants to Mesozoic and Tertiary intrusive rocks. In most outcrops no diagnosis fossils are preserved. Age correlation of these units is based, therefore, solely on similarities to lithologic packages outside the region. Despite the complex tectonic history this area has suffered since the late Paleozoic paleogeographic elements trend southwest into the region from where they are last clearly defined near the California-Nevada border. Dolomitic and calcitic marbles, quartzites, and biotite schists make up a major part of the stratigraphy in many areas. The stratigraphy and lithology of these units strongly suggest that they are correlative with late Precambrian-Cambrian units in the Death Valley region. Possible Ordovician and Devonian marbles also are present within some sections; at least one locality contains stromatoporoids of probable Devonian age. Calcite marbles tentatively correlated with lithologically similar Permian units in the Death Valley area are also represented and appear to be depositionally overlain by Mesozoic( ) shallow-marine and are-derived clastic rocks. Although the western Mojave Desert region has experienced compressional, transcurrent, and extensional deformation since late Paleozoic, our current understanding and restoration of this deformation history does not significantly alter the general southwest Paleozoic paleogeographic trends known to exist farther east.

  17. Egypt.

    PubMed

    1987-12-01

    Attention in this discussion of Egypt is directed to the following: geography; the people; history; government and political conditions; the economy; defense; foreign relations; and relations between Egypt and the US. The population totaled 50.5 million in 1986 with an annual growth rate of 2.8%. The infant mortality rate is 102/1000 (1986), and life expectancy is 58.3 years. Located in the northeastern corner of Africa, Egypt has a land area of about 1 million square kilometers and is bounded by the Mediterranean Sea, Libya, Sudan, the Red Sea, the Gulf of Aqaba, and Israel. Egypt is the most populous country in the Arab world. Egyptians are a fairly homogenous people of Hamitic origin. Mediterranean and Arab influences appear in the north, and there is some mixing in the south with the Nubians of northern Sudan. Egypt has been a unified state for over 5000 years, and archeological evidence indicates that a developed Egyptian society has existed for considerably longer. The constitution of Egypt provides for a strong executive with authority vested in an elected president who can appoint 1 or more vice presidents, a prime minister, and a cabinet. Egypt's legislative body has 458 members -- 448 popularly elected and 10 appointed by the president. Power is concentrated in the hands of the president and the National Democratic Party's majority in the People's Assembly, but opposition parties organize, publish their views, and represent their followers at various levels in the political system. The process of gradual political liberalization begun by Sadat has continued under Mubarak. In fiscal year 1987 the gross domestic product (GDP) reached about US$30 billion. Agriculture and services each contribute about 1/3 of GDP; the remainder comes from industry, petroleum, mining, electricity, and construction. At this time, the Egyptian economy faces several challenges. In 1986 the government of Egypt initiated a major review of economic policy and initiated an economic

  18. Chemical and isotopic constraints on the origin of Wadi El-Tarfa ground waters, Eastern Desert, Egypt.

    SciTech Connect

    Sultan, M.; Sturchio, N. C.; Abdel Hady, Y.; El Anbeawy, M.; Environmental Research; Cairo Univ.

    2000-10-01

    We evaluated the use of the renewable ground water resources of the Eastern Desert to develop sustainable agriculture in Upper Egypt, an alternative that could alleviate some of Egypt's dependence on water from the Nile River. Ground water from shallow aquifers in the Eastern Desert of Egypt, near the intersection of Wadi El-Tarfa and the Nile River, was analyzed for chemical compositions, stable isotope ratios, and tritium activities. The ground water has a range in total dissolved solids of 300 to 5000 mg/L. Values of {delta}D and {delta}{sup 18}O range from -10 to +34 %o and -2 to +5.2 %o, respectively, and defines a line having a slope of 5.7 that intersects the meteoric water line at about {delta}D = -15% on a plot of 8D versus {delta}{sup 18}O. These findings indicate that the water might have been derived by a combination of evaporation of and salt addition to regional precipitation. Only one sample could have been derived directly by evaporation and transpiration of modern Nile River water. Salinization of the ground water could have occurred through dissolution of marine aerosol dry fallout, carbonate minerals, gypsum, and other trace evaporitic minerals at and near the ground surface. Tritium activities ranged from 0.04 to 12.9 TU (tritium unite), indicating that all but one of the samples were derived at least partly from precipitation that occurred within the last 45 years. These data indicate that Nubian Aquifer paleowater is not a significant component of the shallow aquifers of this portion of the Eastern Desert. The most likely source of this ground water is sporadic flash flood events yielding locally voluminous recharge that accumulates in coarse sediments and fractured rock beneath alluvial channels. The magnitude of this renewable ground water resource and its potential for supporting sustainable agriculture require further investigation.

  19. Paleoenvironmental signals and paleoclimatic condition of the Early Maastrichtian oil shales from Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Fathy, Douaa; Wagreich, Michael; Zaki, Rafat; Mohamed, Ramadan S. A.

    2016-04-01

    Early Maastrichtian oil shales are hosted in the Duwi Formation of the Central Eastern Desert, Egypt. The examined member represents up to 20% of the total Duwi Formation. This interval is mainly composed of siliciclastic facies, phosphorites facies and carbonate facies. Oil shales microfacies is mainly composed of smectite, kaolinite, calcite, fluorapatite, quartz and pyrite. They are enriched in a number of major elements and trace metals in particular Ca, P, V, Ni, Cr, Sr, Zn, Mo, Nb, U and Y compared to the post-Archaean Australian shale (PAAS). Chondrite-normalized REEs patterns of oil shales for the studied area display light rare earth elements enrichment relatively to heavy rare earth elements with negative Ce/Ce* and Eu/Eu* anomalies. The most remarkable indicators for redox conditions are enrichments of V, Mo, Ni, Cr, U content and depletion of Mn content. Besides, V/V+Ni, V/Ni, U/Th, Ni/Co, authigentic uranium ratios with presence of framboidal shape of pyrite and its size are reflecting the deposition of these shales under marine anoxic to euxinic environmental conditions. Additionally, the ratio of Strontium (Sr) to Barium (Ba) Sr/Ba reflected highly saline water during deposition. Elemental ratios critical to paleoclimate and paleoweathering (Rb /Sr, Al2O3/TiO2), CIA values, binary diagram between (Al2O3+K2O+Na2O) and SiO2 and types of clay minerals dominated reflect warm to humid climate conditions prevailing during the accumulation of these organic-rich petroleum source rocks.

  20. Oppositely dipping thrusts and transpressional imbricate zone in the Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abd El-Wahed, Mohamed A.

    2014-12-01

    This paper documents the 40-60 km wide ENE-WSW trending Mubarak-Barramiya shear belt (MBSB) in the Central Eastern Desert of Egypt by examining its structural styles, kinematics and geometry. Our study revealed the existence of prevalent dextral and minor sinistral conjugate shear zones. The MBSB is metamorphic belt (greenschist-amphibolite) characterized by at least three post-collisional (740-540 Ma) ductile Neoproterozoic deformation events (D1, D2 and D3) followed by a brittle neotectonic deformation (D4). D1 event produced early top-to-the-northwest thrust displacements due to NW-SE shortening. D2 produced discrete zones of NNW-trending upright folds and culminated in initiation of major NW-trending sinistral shear zones of the Najd Fault System (NFS, at c. 640-540 Ma ago) as well as steeply dipping S2 foliation, and shallowly plunging L2 lineation. NW-to NNW-trending F2 folds are open to steep and vary in plunge from horizontal to vertical. D2 deformational fabrics are strongly overprinted by D3 penetrative structures. D3 is characterized by a penetrative S3 foliation, steeply SE- to NW-plunging and shallowly NE-plunging stretching lineations (L3), asymmetric and sheath folds (F3) consistent with dextral sense of movement exhibited by delta- and sigma-type porphyroclast systems and asymmetric boudinage fabrics. D2-D3 represent a non-coaxial progressive event formed in a dextral NE- over NW-sinistral shear zone during a partitioned transpression in response to E-W-directed compression during oblique convergence between East and West Gondwana developed due to closure of the Mozambique Ocean and amalgamation of the Arabian-Nubian Shield in Cryogenian-early Ediacaran time.

  1. The effects of solar activity on the global solar radiation measured at Khargha Oasis in the Western Dessert of Egypt

    NASA Astrophysics Data System (ADS)

    Shaltout, M.; Mohamed, A.

    Khargha is an Oasis in the Western Desert of Egypt of coordinates lat. 25 o 27/ N, long. 30 o 32 / E, and elevation 77.8 meter over the sea level. It is one of the driest areas in the world, the global solar radiation measured starting from January 1976 till now by station belong to the Egyptian Meteorological Authority. We used the data for the last 25 years of the 20"' Century on the daily bases, it is more than two solar cycles. The annual mean of relative humidity for Khargha is 30, and the total rainfall in mms as annual mean is less than one. Where, the evaporation in mms per day as annual mean is about 16. The total sky cover in oktas as annual mean is 0.4 at the midnight, while it is one oktas at the noon as 2annual mean, and 0.7 oktas on the mean of the day. The annual mean is 6.5 Kwh/rn /day for global solar radiation. Fourier analysis technique used to analysis the time series to show any reflection for the 11-year cycle of the solar activity on the measured global radiation in remote, clean, and dry desert area. The results indicate periodicity's similar to the solar activity periodicities, especially that of the eleven year cycle, in a good indication for the effect of solar activity on the climate change.

  2. Holocene Paleoecology of the Western Tenere Desert, Niger, Africa

    NASA Astrophysics Data System (ADS)

    Sereno, P. C.; Caran, S. C.; Housh, T. B.

    2007-12-01

    Multiple paleontological, sedimentological, and isotopic/ionic geochemical indicators permit reconstruction of the Holocene ecology of the western Tenere Desert (southern Sahara hyper-desert). Modern precipitation is highly erratic, averaging 25 mm yearly, and vegetative cover is negligible. From the early to middle Holocene, however, grassland-shrublands and seasonal to permanent lakes and wetlands predominated, supporting diverse limnic, riparian, and upland communities. Annual precipitation probably was comparable to that of the modern southern Sahel, exceeding 350 mm. Coarse-grained sediment washed into the large lacustrine basin from exposures of metamorphic, plutonic, and volcanic rocks in the nearby Air Massif highland. Lake margins fluctuated in response to runoff and limited ground-water discharge. The water was non-saline and there is no evidence of evaporite deposition. Aquatic and riparian macrophytes thrived, as did an extensive lacustrine-palustrine macrofauna. A Sahelian flora of mixed grasses, thorn shrubs, and perhaps some larger woodland species occupied the contiguous uplands, supporting resident and migratory mammalian and avian faunas. Lake levels were high until 6300 to 5200 BP, possibly as late as 4800 BP locally. Deflation of lacustrine deposits during a subsequent dry period provided finer-grained eolian sediment accreting as proximal dunes. The composition of mineral sediment within the middle to late Holocene dunes is different from, but clearly a subset of the lacustrine deposits. Organic matter reworked from the lake sediment was deposited in the dunes and oxidized in situ, generating CO2 that dissolved in soil moisture, producing bicarbonate. The bicarbonate reacted with calcium from weathered minerals, producing calcic cementation about 5100 BP. The resulting petrocalcic horizon was later exposed, weathered, and colonized by sparse terrestrial vegetation for one or more brief periods. A late phase of pedogenesis concurrent with or

  3. Genesis of the Abu Marawat gold deposit, central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem A.; Akawy, Ahmed

    2010-06-01

    Gold mineralisation at the Abu Marawat mine, central Eastern Desert of Egypt, is related to a system of massive and sheared, milky quartz veins cutting a sequence of Neoproterozoic island arc metavolcanic/volcaniclastic rocks and related banded iron formation (BIF). Sulphide-bearing quartz veins and related hydrothermal breccia bodies display a range of textures including sheared, boudinaged and recrystallised quartz, open space filling and microbreccia. These variable textures imply a complex history of crack-seal mechanism characterising the relation between mineral deposition and a major N-S-trending shear zone, during a late brittle-ductile deformation event which affected the area at about 550 Ma. Gold-base metal mineralisation is associated with brecciation and fracturing of the iron ore bands, close to silicified shears and related quartz veins. The auriferous quartz lodes are characterised by the occurrence of visible pyrite-chalcopyrite ± pyrrhotite ± sphalerite ± galena mineralisation. Gold is refractory in pyrite and chalcopyrite, but rare visible gold/electrum and telluride specks were observed in a few samples. Hydrothermal alteration includes pervasive silicification, pyritisation, sericitisation, carbonatisation confined to a delicate set of veins and altered shears, and a more widespread propylitic alteration assemblage (quartz + chlorite + pyrite + calcite ± epidote). Fluid inclusion petrography and microthermometric studies suggest heterogeneous trapping of a low-salinity (1.4-6.7 wt.% eq. NaCl) aqueous solution and a carbonic fluid. Evidence for fluid immiscibility during ore formation includes variable liquid/vapour ratios in inclusions along individual trails and bulk inclusion homogenisation into liquid and occasionally to vapour at comparable temperatures. The trapping conditions of intragranular aqueous-carbonic inclusions approximate 264-378 °C at 700-1300 bar. Similar temperature estimates have been obtained from Al

  4. Rare metal-bearing and barren granites, Eastern Desert of Egypt: geochemical characterization and metallogenetic aspects

    NASA Astrophysics Data System (ADS)

    Mohamed, F. H.

    1993-11-01

    Three "younger granite" plutons from the Eastern Desert of Egypt are studied: petrographic and geochemical characteristics of the barren pink granites at Wadi Sikait and Wadi Nugrus are similar, of alkaline, mildly peraluminous nature and are enriched in LIL-elements and LREE with moderate negative Eu anomalies. In contrast, the Sn-Ta-W-bearing albite granite of Abu Dabbab is alkaline, peraluminous muscovite granite; its chemical specialization is manifested by the pronounced enrichment in Ta, Sn, W, F, Rb and Li coupled with marked depletion in Ca, Ti, Mg, Sr and Ba. Elemental ratios (e.g., K/Rb, Rb/Sr, Ba/Rb) discriminate the albite granite and the pink granites into "mineralized and barren granites", respectively. The albite granite is derived from Na-rich magma of within-plate characteristics. Fluorine was an important complexing anion during magmatic evolution history. The albite granite is emplaced at shallow depth (<100 MPa) and at the intersection of structural weaknesses. The pink granites might have a crustal and/or LIL-element enriched mantle sources, in which the subduction-related fingerprints are partly obliterated. For both types, reactivation of regional structures played a significant role in magma generation. Acid metasomatism is mainly manifested by the development of thin greisen veins along fracture systems in the albite granite. The chemistry of greisenization using mass balance approach reveals that the process is accompanied by dramatic increase in SiO 2, Fe 2O 3, MnO, F, Sn and Li as well as significant loss in Na 2O, K 2O, Ba, Nb and Zn. The process causes a significant increase in volume (30%). Changes in chemical components are consistent with the observed mineralogical changes. Microprobe results reveal that the wolframite crystals are typically huebnerite with Fe-rich cores and Mn-rich rims. Compositional variations in wolframite crystals are attributed to the physicochemical conditions (pH, T, etc.) and chemistry of the ore

  5. The Neoproterozoic Abu Dahr ophiolite, South Eastern Desert, Egypt: petrological characteristics and tectonomagmatic evolution

    NASA Astrophysics Data System (ADS)

    Gahlan, Hisham A.; Azer, Mokhles K.; Khalil, Ahmed E. S.

    2015-10-01

    The Neoproterozoic Abu Dahr ophiolite, South Eastern Desert, Egypt, is one of the best preserved and least dismembered ophiolite successions in the Arabian-Nubian Shield. It contains a Penrose-type ophiolite sequence from mantle section below mafic crust upward to oceanic sedimentary cover overlying mafic volcanics, although the original magmatic (stratigraphic) contact between the mantle and crustal sections is disrupted by tectonism. The Abu Dahr ophiolite is metamorphosed under greenschist facies conditions, and low-temperature alteration is widespread. Petrography reveals that: (i) the mantle is homogenous, serpentinized, and dominated by harzburgite and less abundant dunite; (ii) the cumulate ultramafics are represented by wehrlite and pyroxenite; and (iii) the crustal section is represented by metagabbros, meta-anorthosites and metabasalts. The Abu Dahr serpentinized peridotites show high Mg# (0.92-0.93), with enrichment of Ni, Cr and Co, and depletion of Al2O3 and CaO, and nearly flat and unfractionated REE chondrite-normalized pattern. Major and trace element characteristics of the Abu Dahr metagabbro and metabasalt (crustal section) indicate a tholeiitic to calc-alkaline affinity. Units of the crustal section have low-Nb and Zr concentrations, low Dy/Yb and relatively elevated La/Yb ratios, high U/Yb and Th/Yb ratios, and LREE enriched chondrite-normalized pattern. All of the Abu Dahr ophiolite units have trace-element signatures characterized by enrichment of LILE over HFSE. Rare and trace element patterns indicate a genetic link between the Abu Dahr mantle, cumulate ultramafics, and crust. Chromian spinel has survived metamorphism and is used as a petrogenetic indicator in the Abu Dahr serpentinized peridotites. The spinel is homogeneous with a limited composition, and shows high-Cr# (>0.6) combined with low-TiO2 character (mostly <0.1 wt.%). The Abu Dahr ophiolite is interpreted as a fragment of depleted oceanic lithosphere that experienced high degrees

  6. Greenstone-hosted lode-gold mineralization at Dungash mine, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem; Weihed, Pär

    2014-11-01

    The auriferous quartz ± carbonate veins at Dungash mine, central Eastern Desert of Egypt, are confined to ∼E-trending dilation zones within variably foliated/sheared metavolcanic/volcaniclastic rocks. The vein morphology and internal structures demonstrate formation concurrent with a dextral shear system. The latter is attributed to flexural displacement of folded, heterogeneous rock blocks through transpression increment, late in the Neoproterozoic deformation history of the area. Geochemistry of the host metavolcanic/metavolcaniclastic rocks from the mine area suggests derivation from a low-K, calc-alkaline magma in a subduction-related, volcanic arc setting. In addition, chemistry of disseminated Cr-spinels further constrain on the back-arc basin setting and low-grade metamorphism, typical of gold-hosting greenstone belts elsewhere. Mineralogy of the mineralized veins includes an early assemblage of arsenopyrite-As-pyrite-gersdorffite ± pyrrhotite, a transitional pyrite-Sb-arsenopyrite ± gersdorffite assemblage, and a late tetrahedrite-chalcopyrite-sphalerite-galena-gold assemblage. Based on arsenopyrite and chlorite geothermometers, formation of gold-sulfide mineralization occurred between ∼365 and 280 °C. LA-ICP-MS measurements indicate the presence of refractory Au in arsenian pyrite (up to 53 ppm) and Sb-bearing arsenopyrite (up to 974 ppm). Abundant free-milling gold associated with the late sulfide assemblage may have been mobilized and re-distributed by circulating, lower temperature ore fluids in the waning stages of the hydrothermal system. Based on the isotopic values of vein quartz and carbonate, the calculated average δ18OH2O values of the ore fluids are 5.0 ± 1.4‰ SMOW for quartz, and 3.3 ± 1.4‰ for vein carbonate. The measured carbonate δ13C values correspond to ore fluids with δ13CCO2 = -6.7 ± 0.7‰ PDB. These results suggest a mainly metamorphic source for ore fluids, in good agreement with the vein morphology, textures and

  7. Genesis of secondary uranium minerals associated with jasperoid veins, El Erediya area, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Abd El-Naby, Hamdy H.

    2008-11-01

    Uranium mineralization in the El Erediya area, Egyptian Eastern Desert, has been affected by both high temperature and low temperature fluids. Mineralization is structurally controlled and is associated with jasperoid veins that are hosted by a granitic pluton. This granite exhibits extensive alteration, including silicification, argillization, sericitization, chloritization, carbonatization, and hematization. The primary uranium mineral is pitchblende, whereas uranpyrochlore, uranophane, kasolite, and an unidentified hydrated uranium niobate mineral are the most abundant secondary uranium minerals. Uranpyrochlore and the unidentified hydrated uranium niobate mineral are interpreted as alteration products of petscheckite. The chemical formula of the uranpyrochlore based upon the Electron Probe Micro Analyzer (EPMA) is A {left( {{text{U}}_{{1.07}} {text{Ca}}_{{0.28}} {text{Pb}}_{{0.03}} {text{Na}}_{{0.21}} {text{Mg}}_{{0.02}} } right)}_{{Σ 1.6}} B {left( {{text{Nb}}_{{0.57}} {text{Si}}_{{0.62}} {text{Zr}}_{{0.35}} {text{P}}_{{0.20}} {text{Fe}}_{{0.17}} {text{Al}}_{{0.06}} {text{Ti}}_{{0.03}} } right)}_{{Σ 2}} . It is characterized by a relatively high Zr content (average ZrO2 = 6.6 wt%). The average composition of the unidentified hydrated uranium niobate mineral is ^{{text{U}}} {left( {{text{U}}_{{1.89}} {text{Ca}}_{{0.49}} {text{Pb}}_{{0.13}} {text{Na}}_{{0.06}} {text{Mg}}_{{0.02}} } right)}_{{Σ 2.59}} ^{{{text{Nb}}}} {left( {{text{Nb}}_{{1.31}} {text{Fe}}_{{0.34}} {text{Si}}_{{0.14}} {text{P}}_{{0.10}} {text{Ti}}_{{0.05}} {text{Zr}}_{{0.03}} {text{Al}}_{{0.03}} } right)}_{{Σ 2.0}} , where U and Nb represent the dominant cations in the U and Nb site, respectively. Uranophane is the dominant U6+ silicate phase in oxidized zones of the jasperoid veins. Kasolite is less abundant than uranophane and contains major U, Pb, and Si but only minor Ca, Fe, P, and Zr. A two-stage metallogenetic model is proposed for the alteration processes and uranium mineralization at

  8. Diagenesis of the lower Eocene Thebes Formation, Gebel Rewagen area, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Shaaban, Mohamad N.

    2004-03-01

    The diagenesis of lower Eocene shallow water carbonates with flint was studied in the Gebel Rewagen area, Eastern Desert, Egypt. The carbonates are mainly wackestones to packstones with benthic bioclasts embedded in a dark red luminescent micrite matrix. The studied succession displays a complex diagenetic history that involves syngenetic and late diagenetic processes. Silica, which exists either as persistent bands, nodules and/or silicified benthic bioclasts shows a distinctive pattern regarding its distribution, source, depositional environments and timing. Three lines of evidence support a syngenetic origin of the chert bands: (1) they alternate in a cyclic manner within the host carbonates and (2) they exhibit noticeable lateral persistence throughout the investigated area following the strata boundaries and (3) there is a lack of any carbonate dissolution in limestone adjacent to chert bands. The deposition of silica bands in association with shallow water carbonates is possibly related to eustatic sea-level changes, which were accompanied by episodic variations in silica and carbonate productivities. With a relative sea-level fall and the establishment of a lowstand period at the end of the early Eocene, a basinward shift of the groundwater zones is expected within the carbonate platform. During this period some late diagenetic processes took place, which involve: (1) the formation of siliceous and carbonate concretionary growths, (2) partial silicification of bioclasts, (3) neomorphic stabilization of the CaCO 3 bioclasts and (4) the formation of equant calcite cement. Siliceous and carbonate concretions are believed to have taken place within microenvironments created and controlled by sulphate-reducing bacteria and physico-chemical and kinetic factors near a marine-meteoric water mixing zone. This is inferred from the distribution of iron sulphides, the non-ferroan nature of all concretions and the depleted δ13C (-5.4‰ to -6.0‰ PDB) and δ18O (-5.8

  9. Origin of Neoproterozoic ophiolitic peridotites in south Eastern Desert, Egypt, constrained from primary mantle mineral chemistry

    NASA Astrophysics Data System (ADS)

    Khedr, Mohamed Zaki; Arai, Shoji

    2013-10-01

    The ophiolitic peridotites in the Wadi Arais area, south Eastern Desert of Egypt, represent a part of Neoproterozoic ophiolites of the Arabian-Nubian Shield (ANS). We found relics of fresh dunites enveloped by serpentinites that show abundances of bastite after orthopyroxene, reflecting harzburgite protoliths. The bulk-rock chemistry confirmed the harzburgites as the main protoliths. The primary mantle minerals such as orthopyroxene, olivine and chromian spinel in Arais serpentinites are still preserved. The orthopyroxene has high Mg# [=Mg/(Mg + Fe2+)], ~0.923 on average. It shows intra-grain chemical homogeneity and contains, on average, 2.28 wt.% A12O3, 0.88 wt.% Cr2O3 and 0.53 wt.% CaO, similar to primary orthopyroxenes in modern forearc peridotites. The olivine in harzburgites has lower Fo (93-94.5) than that in dunites (Fo94.3-Fo95.9). The Arais olivine is similar in NiO (0.47 wt.% on average) and MnO (0.08 wt.% on average) contents to the mantle olivine in primary peridotites. This olivine is high in Fo content, similar to Mg-rich olivines in ANS ophiolitic harzburgites, because of its residual origin. The chromian spinel, found in harzburgites, shows wide ranges of Cr#s [=Cr/(Cr + Al)], 0.46-0.81 and Mg#s, 0.34-0.67. The chromian spinel in dunites shows an intra-grain chemical homogeneity with high Cr#s (0.82-0.86). The chromian spinels in Arais peridotites are low in TiO2, 0.05 wt.% and YFe [= Fe3+/(Cr + Al + Fe3+)], ~0.06 on average. They are similar in chemistry to spinels in forearc peridotites. Their compositions associated with olivine’s Fo suggest that the harzburgites are refractory residues after high-degree partial melting (mainly ~25-30 % partial melting) and dunites are more depleted, similar to highly refractory peridotites recovered from forearcs. This is in accordance with the partial melting (>20 % melt) obtained by the whole-rock Al2O3 composition. The Arais peridotites have been possibly formed in a sub-arc setting (mantle wedge), where

  10. Determination of chromium and trace elements in El-Rubshi chromite from Eastern Desert, Egypt by neutron activation analysis.

    PubMed

    El-Taher, A

    2010-09-01

    Neutron activation analysis (NAA) is one of the most powerful analytical techniques for multielement determination of rocks. In the present work NAA and HPGe detector gamma-spectroscopy was used to determine chromium and 15 minor and trace elements qualitatively and quantitatively from chromite rock samples collected from El-Robshi area in the Eastern Desert, Egypt. The samples were properly prepared together with their standards and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor. Short time irradiation (1-5min) was used to determine Mg, Ti and Mn. Long time irradiation (6h) was used to determine Na, Ga, As, La, Sc, Cr, Fe, Co, Zn, Zr, Ce, Ce, Yb, Lu, Hf and Ta. In El-Robshi chromite comprises 18 sites, more than 100 lenses of massive chromite, more than 2700 tons averaging 44% Cr(2)O(3) and the average of (51)Cr 40.2%. PMID:20444611

  11. Estimating and interpretation of radioactive heat production using airborne gamma-ray survey data of Gabal Arrubushi area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Youssef, Mohamed A. S.

    2016-02-01

    The present work deals with mapping of radioactive heat production from rocks in the Gabal Arrubushi area in the Central Eastern Desert of Egypt based on airborne spectral gamma-ray survey data. The results show that the radioactive heat production in the areas ranges from 0.01 μWm-3 to 5.2 μWm-3. Granites, muscovite and sericite schists in the western part of Gabal Arrubushi area have abnormally high radioactive heat production values from 2.57 μWm-3 to 4.44 μWm-3. Meanwhile, the higher averages of radioactive heat production of these rock units change from 1.21 μWm-3 to 1.5 μWm-3. The intermediate averages of heat production of felsitic mylonite schist, chlorite schist, felsites, amphibolites and Hammamat sediments are below the crustal average value range, i.e., from 0.8 μWm-3 to 1.2 μWm-3. The lowest averages of heat production values are less than 0.8 μWm-3 and found in the following rock units: Wadi sediments, rhyolites, andesites, gabbro and serpentinites.

  12. Late Pliocene age for the Atacama Desert: Implications for the desertification of western South America

    NASA Astrophysics Data System (ADS)

    Hartley, Adrian J.; Chong, Guillermo

    2002-01-01

    The Atacama Desert forms one of the major hyperarid deserts of the world. Previous studies suggest that desertification commenced at 14 Ma during global climate desiccation. Sedimentologic data from middle Miocene to upper Pliocene successions in the modern Atacama Desert indicate that a semiarid climate persisted from 8 to 3 Ma, punctuated by a phase of increased aridity at ca. 6 Ma. As such, hyperaridity did not commence until the late Pliocene. Implications are (1) that the rain shadow generated by the Andean Cordillera has had a minor influence on climate change, and (2) that the upwelling, north- flowing, cold Humboldt Current, although important in establishing the generally arid climate of western South America, did not control the shift to hyperaridity. The formation of the hyperarid Atacama Desert in the late Pliocene accompanied the development of the current phase of aridification in the Sahara and Namib Deserts and is attributed to a phase of global climate cooling.

  13. Petrology and petrogenesis of the older and younger granitoids of Wadi Beizah area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Ragab, A. I.; Menesy, M. Y.; Diab, M. M.

    The studied granitoids of Wadi Beizah area, Central Eastern Desert, Egypt, are represented by older arc-granitoids intruded by a post-collisional stock of younger pink granite. The arc-granitoids (I-type) cover a wide compositional spectrum from meladiorites, diorites, quartzdiorites/monzodiorites and tonalites, to leucogranodiorites. Their distribution pattern is unimodal dominated by diorites. They are of low-K calc-alkaline character and represent the plutonic rocks of the mature, ensimatic island arc stage. Three models for the geotectonic environment of the younger granites of the Eastern Desert of Egypt have been suggested: (1) Within-plate, rifting, tensional environment similar to the Oslo Rift of Norway (Greenberg, 1981) Stern et al., 1984, 1986), (2) Extensive crustal anatexis during collisional tectonics, compression, thickening of the crust and thrust imbrication (Hussein et al., 1982; Ragab, 1987b), (3) Active continental margin geotectonic environment (Abdel-Rahman and Martin, 1987). These three models are discussed in detail. The present workers believe that the Younger Granites in general are the products of extensive crustal anatexis at the culmination of the Pan-African orogenic cycle when arc-arc suturing is complete. Recent studies revealed a low-angle thrust event in the Central Eastern Desert followed the initial arc-arc collision and continued after the deposition of the molasse-type sediments (Ries et al., 1983; El-Ramly et al., 1984; Greiling et al., 1984; Habib et al., 1985; Greiling and El-Ramly, 1985) which indicate thickening of the crust and compression regime at the time of emplacement of the Younger Granites. The dominance of ≪granite minimum≫ composition of these late orogenic granites suggests extensive crustal anatexis. Their low Nb-content (< 40 ppm) precludes within-plate hot-spot related magma, in comparison with: (1) The post-Pan-African (400-100 M.a.) granitic rocks from the NE Sudan which on a geochemical evidence are

  14. Desert landforms of southwest Egypt: A basis for comparison with Mars

    NASA Technical Reports Server (NTRS)

    El-Baz, F. (Editor); Maxwell, T. A. (Editor)

    1982-01-01

    Geologic interpretations of The Gilf Kebir-Uweinat of Apollo-Soyuz photographs were verified. The photographs and LANDSAT images showed features reminiscent of those depicted by Mariner and Viking missions to Mars. These features were to better understand their morphologic analogs on Mars. It is indicated that climate change played a significant role in the formation of the eastern Sahara. It is also revealed that correlations between the eolian features in southwestern Egypt and the wind blown patterns on the surface of Mars result in a better understanding of eolian activity on both planets.

  15. Ground-water quality and geochemistry, Carson Desert, western Nevada

    USGS Publications Warehouse

    Lico, Michael S.; Seiler, R.L.

    1994-01-01

    Aquifers in the Carson Desert are the primary source of drinking water, which is highly variable in chemical composition. In the shallow basin-fill aquifers, water chemistyr varies from a dilute calcium bicarbonate-dominated water beneath the irrigated areas to a saline sodium chloride- dominated water beneath unirrigated areas. Water samples from the shallow aquifers commonly have dissolved solids, chloride, magnesium, sulfate, arsenic, and manganese concentrations that exceed State of Nevada drinking-water standards. Water in the intermediante basin-fill aquifers is a dilute sodium bicarbonate type in the Fallon area and a distinctly more saline sodium chloride type in the Soda Lake-Upsal Hogback area. Dissolved solids, chloride, arsenic, fluoride, and manganese concen- trations commonly exceed drinking-water standards. The basalt aquifer contains a dilute sodium bicarbonate chloride water. Arsenic concentrations exceed standards in all sampled wells. The concen- trations of major constituents in ground water beneath the southern Carson Desert are the result of evapotranspiration and natural geochemical reactions with minerals derived mostly from igneous rocks. Water with higher concentrations of iron and manganese is near thermodynamic equilibrium with siderite and rhodochrosite and indicates that these elements may be limited by the solubility of their respective carbonate minerals. Naturally occurring radionuclides (uranium and radon-222) are present in ground water from the Carson Desert in concen- tratons higher than proposed drinking-water standards. High uranium concentrations in the shallow aquifers may be caused by evaporative concentration and the release of uranium during dissolution of iron and manganese oxides or the oxidation of sedimentary organic matter that typically has elevated uranium concentrations. Ground water in the Carson Desert does not appear to have be contaminated by synthetic organic chemicals.

  16. Natural radionuclide concentrations in granite rocks in Aswan and Central-Southern Eastern Desert, Egypt and their radiological implications.

    PubMed

    Issa, Shams A M; Uosif, M A M; Abd el-Salam, L M

    2012-07-01

    Different types of granites, used extensively in local construction, were collected from five localities in Egypt, namely: Abu Ziran (Central Eastern Desert), Gabal El Maesala (Aswan) and three areas from Wadi Allaqi, (Gabal Abu Marw, Gabal Haumor and Gabal um Shalman), in the South Eastern Desert. Granite samples were studied radiologically, petrographically and geochemically. The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples by using gamma spectrometry [NaI (Tl) 3'×3']. The activity concentrations of (226)Ra, (232)Th and (40)K in the selected granite samples ranged from 9±0.5 to 111±7, 8±1 to 75±4 and 100±6 to 790±40 Bq kg(-1), respectively. The external hazard index (H(ex)), absorbed dose and annual effective dose rate were evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. The calculated radium equivalents were lower than the values recommended for construction materials (370 Bq kg(-1)). The excess lifetime cancer risks were also calculated. Petrographically, the granites studied are varied in the form of potash-feldspar, quartz, plagioclase, mica and hornblende. The accessory minerals are zircon, apatite and allanite. Geochemically, the chemical composition of the granite is studied especially for major oxides. They are characterized to have SiO(2), K(2)O, Na(2)O and Al(2)O(3) with depletion in CaO, MgO, TiO(2) and P(2)O(5). PMID:22147926

  17. Extending the western North American Proterozoic and Paleozoic continental crust through the Mojave Desert

    SciTech Connect

    Martin, M.W.; Walker, J.D. )

    1992-08-01

    Data supporting the existence of Proterozoic basement in the central and western Mojave Desert include U-Pb zircon geochronology and Nd, Sr, and Pb isotopic values of quartzofeldspathic gneisses, detrital zircon provenance ages, and the presence of basement clasts in Paleozoic and Mesozoic conglomerates. These data corroborate existing isotopic data from Mesozoic and Tertiary intrusive rocks that suggest involvement of Proterozoic crust in their genesis. Exposures of Proterozoic basement and Late Proterozoic and Paleozoic transitional miogeoclinal-cratonal facies trends in the central and western Mojave Desert consistently imply that cratonal North America continues westward uninterrupted through this region to the San Andreas fault. These data place geographic limits on the position of several pre-Tertiary tectonic elements speculated to exist in the Mojave Desert.

  18. Natural radioactivity levels and radiation hazard indices in granite from Aswan to Wadi El-Allaqi southeastern desert, Egypt.

    PubMed

    El-Taher, A; Uosif, M A M; Orabi, A A

    2007-01-01

    Studies on radiation level and radionuclide distribution in granite from Aswan to Wadi El-Allaqi area that is located in southeastern desert of Egypt were undertaken. The samples collected from five locations: Gabal El Mesala, Umm Hibal, Abu Herigle, Abu Marw and Deneibit El Quleib. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area environment, and this study will be used as reference information to assess any changes in the radioactive background level due to geological processes. The highest average values of 226Ra and 232Th concentrations (24.00 and 31.28 Bq kg(-1), respectively) were observed at Abu Herigle region, whereas the highest average value of 40K concentration, 589.95 Bq kg(-1), was detected in Umm Hibal. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy h(-1), and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq kg(-1). Also the representative external hazard index values for the corresponding samples were also estimated and given. PMID:17569689

  19. Rare earth elements content in geological samples from eastern desert, Egypt, determined by instrumental neutron activation analysis.

    PubMed

    El-Taher, A

    2010-09-01

    Twenty representative geological samples (tonalite, granodiorite, adamellite, syenogranite, rapakivi syenogranite, alkali feldspar granite and monzogranite) were collected from G. Kattar area in Eastern Desert, Egypt, for analysis by instrumental neutron activation as a sensitive nondestructive analytical tool for the determination of 14 rare earth elements (REEs) and to find out the following: (1) what information could be obtained about the REEs and distribution patterns of REEs in geological samples under investigation, (2) to estimate the accuracy, reproducibility and detection limit of the INAA method in case of the given samples. The samples were properly prepared together with standard reference material and simultaneously irradiated in a neutron flux of 7x10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by an HPGe detector and the analysis was done by means of a computerized multichannel analyzer. The choice of the nuclear reaction, irradiation and decay times, and of the proper gamma radiation in counting are presented and discussed. The results are found to be in good agreement with certified values. PMID:20236830

  20. Groundwater quality and management in arid and semi-arid regions: Case study, Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Amer, Reda; Ripperdan, Robert; Wang, Tao; Encarnación, John

    2012-07-01

    This study presents a model budget for groundwater in the Central Eastern Desert of Egypt. The stable isotopic composition and hydrochemistry of groundwater samples collected from different aquifers were determined to identify recharge sources and water quality. Stable isotopic values suggest that shallow alluvial and fracture zone aquifers are recharged from seasonal precipitation, while groundwater in deeper sedimentary sub-basins is paleowater that was recharged during periods of less arid regional climate. Hydrochemical analysis indicates elevated salinity in each aquifer type, which is attributed to leaching and dissolution of terrestrial salts and to mixing with marine water. Groundwater from sedimentary sub-basin aquifers can be treated and used for drinking and domestic purposes. Groundwater from shallow alluvial and fracture zone wells is suitable for animal husbandry and mineral ore dressing. A model water budget shows that approximately 4.8 × 109 m3 of recoverable groundwater is stored in sedimentary sub-basin aquifers, or approximately 550 years of water at present utilization rates.

  1. Magmatic and solid state structures of the Abu Ziran pluton: Deciphering transition from thrusting to extension in the Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Fritz, Harald; Loizenbauer, Jürgen; Wallbrecher, Eckart

    2014-11-01

    The 606 Ma old Abu Ziran granite of the Eastern Desert of Egypt intruded the southern margin of the Meatiq dome in a sinistral shear extensional setting. Its emplacement was enabled by a system of NW-trending sinistral shears, related Riedel shears and N-S extensional shear zones and faults. Magmatic flow was east-directed and controlled by Riedel shears that progressively rotated to an orientation favourable for extension. Strain markers that document magmatic flow show eastward decreasing strain together with strain increase from pluton centre to margins. This is explained by Newtonian flow between non-parallel plates and differences in flow velocities across the pluton. Solid state fabrics including shear fabrics, orientation of late magmatic dykes and quartz tension gashes, together with quartz C-axes distributions, document southward extensional shear within the solidified pluton and adjacent host rocks. Extensional shear is correlated with exhumation of the Meatiq dome coeval and soon after pluton solidification (585 Ma). Pressure temperature evolutionary paths, derived from fluid inclusions, show a clockwise path with exhumation by isothermal decompression in the Meatiq dome. By contrast, the overlying volcanosedimentary nappes experienced an anti-clockwise path released by temperature rise due to pluton emplacement followed by isobaric cooling. Quartz fabrics indicate high-temperature coaxial N-S flow in the northern Meatiq dome and lower-temperature, non-coaxial southward flow within the overlaying superficial nappe. This is explained by the exhumation process itself that progressively localised into simple shear domains when rocks approached higher crustal levels. Late extension at ca. 580 Ma was pure shear dominated and resulted in reversal of shear, now dextral, in the western Meatiq shear zone.

  2. North-South Partnership in Space Research and Application: Space Research Center at Minufiyia University, Egypt, as Case Study

    NASA Astrophysics Data System (ADS)

    Shaltout, M.

    With the starting the year 2002 the Minufiyia University Council taked an Issue by construction Space Research Center, as a first Center for Space Research in the Egyptian Universities (20 Universities), as a part from the Desert Environment Research Institute for temporal time, then after the growth, it will be independent center. The green area of Egypt (Nile Valley and Delta) are 4% only from the total area of Egypt, the remain 96% is desert area. The most useful thing is to study the desert from space. For that the suggested projects to be performed in this new center are: 1.Monitoring the storage tanks of the underground water in the Egyptian Desert (Sahara) by artificial satellites as GRACE of NASA and DLR. 2.Building 32 meter Radio telescope at Abu-Simbel in the South of Egypt as part of the European VLBI network (EVN) to cover the gab between the radio telescope in the western Europe and the radio telescope at Hartebessthock in South Africa. The cooperation of International interested institutions is being explored for this important project of Egypt. 3.Solar activity and the climatic changes through the 21st century as clarified by global solar radiation data at Khargha Oases at the western desert of Egypt. 4.Testing of the Martian exploration instruments for 2003 and 2005 space trips to Mars in the western desert of Egypt, as it is the driest area in the worl d, where are similarity between the dry atmosphere of Sahara and the atmosphere of Mars, also in the soil, and dry valleys. In collaboration with NASA and ESA. 5.Studding the eastern structure, due to meteoric impact in the western desert of Egypt since 28 Million years. Also, studding the meteors chemistry, for meteors found in the Egyptian desert, and the origin of life as meteor (Nachlet) in collaboration with NASA and ESA. Solar energy and humidity distribution over Sahara from artificial Satellite Meteostat observations.

  3. The way forward in capacity building in developing countries: space research center at Minoufiyia University, Egypt, as case study

    NASA Astrophysics Data System (ADS)

    Mosalam Shaltout, M. A.

    With the starting the year 2002 the Menoufiyia University Council taked an Issue by construction Space Research Center, as a first Center for Space Research in the Egyptian Universities (20 Universities), as a part from the Desert Environment Research Institute for temporal time, then after the growth, it will be independent center. The green area of Egypt (Nile Valley and Delta) are 4% only from the total area of Egypt, the remain 96% is desert area. The most useful thing is to study the desert from space. For that the suggested projects to be performed in this new center are: 1. Monitoring the storage tanks of the underground water in the Egyptian Desert (Sahara) by artificial satellites as GRACE of NASA and DLR. 2. Building 32 meter Radio telescope at Abu-Simbel in the South of Egypt as part of the European VLBI network (EVN) to cover the gab between the radio telescope in the western Europe and the radio telescope at Hartebessthock in South Africa. The cooperation of International interested institutions is being explored for this important project of Egypt. 3. Solar activity and the climatic changes through the 21st century as clarified by global solar radiation data at Khargha Oases at the western desert of Egypt. 4. Testing of the Martian exploration instruments for 2005 space trips to Mars in the western desert of Egypt, as it is the driest area in the world, where are similarity between the dry atmosphere of Sahara and the atmosphere of Mars, also in the soil, and dry valleys. In collaboration with NASA and ESA. 5. Studding the eastern structure, due to meteoric impact in the western desert of Egypt since 28 Million years. Also, studding the meteors chemistry, for meteors found in the Egyptian desert, and the origin of life as meteor (Nachlet) in collaboration with NASA and ESA. 6. Solar energy and humidity distribution over Sahara from artificial Satellite Meteostat observations.

  4. Seismic hazard studies in Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Abuo El-Ela A.; El-Hadidy, M.; Deif, A.; Abou Elenean, K.

    2012-12-01

    The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba-Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal.

  5. Investigation of geotechnical parameters from CSEM mapping and monitoring data at the oases Kharga and Baris of Sahara desert, Egypt

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Oleg; Attia, Magdy; Khalil, Ahmed; Mekkawi, Mahmoud; Soliman, Mamdouh

    2016-04-01

    The site of investigation, oasis Kharga, is located at about 600 km south of Cairo, Egypt; Baris is about 90 km from Kharga also to south and towards more inside the desert. The work was aimed to investigate the rock mass stability at Baris and to estimate the water intake in the Oasis Kharga. A controlled source electromagnetic (CSEM) approach developed earlier by IGF UB RAS (Geophysical Federal Institute, Ural Branch of Russian Academy of Science) is applied to image the ranked deformation levels in the massive structure of the Baris. The wide profile system of observation has been used to monitor the three components of the alternating magnetic field along predefined measuring lines in the study area. Here we can show the first results that we shall continue during some cycles of monitoring. The second part of our work was linked with mapping the massif structure inside the oasis City, where only using our device we could construct the geoelectrical sections for 5 profiles and show the real structure of the water volume and its complicated structure up to 200 meters depth recording the values of real not apparent resistivity. The analytical treatments provided good information about the structure of the rock massive and its rank of degradation, the lateral distribution of the geotechnical heterogeneity, and finally a conclusive outcome about foundation stability. We can conclude that the general dynamic state close to the destruction level within the investigation areas is getting worse over the time; this is reflected in the crack's densities and positions, also on the changes in the lateral distribution of geoelectrical heterogeneity as an indicator of the saturation of the surface rock in the study area with water [1,2]. References 1. Magdy A. Atya, Olga A. Hachay, Mamdouh M. Soliman, Oleg Y. Khachay, Ahmed B. Khalill, Mahmoud Gaballah, Fathy F.Shaaban and Ibrahim A.El. Hemali. CSEM imaging of the near surface dynamics and its impact for foundation stability

  6. Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt.

    PubMed

    Abbady, Adel G E; El-Arabi, A M; Abbady, A

    2006-01-01

    Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 microWm(-3) (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 microWm(-3) (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites. PMID:16120480

  7. Shelf architectures of an isolated Late Cretaceous carbonate platform margin, Galala Mountains (Eastern Desert, Egypt)

    NASA Astrophysics Data System (ADS)

    Scheibner, C.; Marzouk, A. M.; Kuss, J.

    2001-12-01

    An asymmetrical carbonate platform margin to basin transect has been investigated in the Upper Campanian-Maastrichtian succession of the Galala Mountains, northern Egypt. Identification of systems tracts and their lateral correlation was possible in slope sections only, whereas the monotonous chalk-marl alternations of the basinal sections could not be subdivided with respect to sequence stratigraphic terminology. The platform asymmetry is expressed by varying large-scale depositional architectures exhibiting a rimmed platform with a sigmoidal slope curvature in south-easterly dip-sections and a ramp with a linear slope curvature in south-westerly dip-sections. The rimmed platform is subdivided into a gentle upper slope and a steep lower slope. The platform formed as a result of the initial topography that was controlled by the tectonic uplift of the Northern Galala/Wadi Araba Syrian Arc structure. The calculated angles of the steep lower slope of the rimmed part range from 5 to 8°, whereas the ramp part has an angle of less than 0.1°.

  8. Late Carboniferous macrofauna from Wadi Araba, Eastern Desert, Egypt, and their paleoecological implications

    NASA Astrophysics Data System (ADS)

    El-Shazly, Soheir H.

    2011-12-01

    The Upper Carboniferous rocks at Wadi Araba are highly rich in macrofaunal content. The systematic description of these macrofauna reveals the identification of 34 species, 17 species of which are recorded for the first time from the Carboniferous rocks of Egypt, among them the trilobite Cummingella ( C.) carringtonensis carringtonensis (Etheridge). Moreover, the paleoeclogic study on some crinoid and brachiopod specimens shows predation and commensal relations with some endo and epibionts fauna. The study presents also crinoidal infestation by Oxytoma ( Palmoxytoma) cygnipes (Young and Bird) species, a relation which is recorded for the first time. Evidences of crushing or biting damages on some brachiopod shells that have been attributed to nautiloids or conchostracan arthropods are also reported. The microfacies study of the carbonate rocks in this area reveals the identification of five microfacies types indicating that the rocks were deposited in an environment ranging from restricted inner to outer shelf lagoonal environments with open circulation. The microfacies study indicates also the presence of two types of microorganisms, the filamentous microorganisms and the fossilized microbial carbonate communities, which played an important role in iron oxide precipitation and rock diagenesis.

  9. Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt.

    PubMed

    Hanna, Amira L; Youssef, Hanan H; Amer, Wafaa M; Monib, Mohammed; Fayez, Mohammed; Hegazi, Nabil A

    2013-01-01

    North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium, Bacillus pumilus, Bacillus polymexa, Bacillus macerans, Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans, Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera, Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola. Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El

  10. Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt

    PubMed Central

    Hanna, Amira L.; Youssef, Hanan H.; Amer, Wafaa M.; Monib, Mohammed; Fayez, Mohammed; Hegazi, Nabil A.

    2012-01-01

    North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium,Bacillus pumilus, Bacillus polymexa,Bacillus macerans,Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans,Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera,Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola.Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El

  11. Construction of a hydrologic model for estimating Wadi runoff and ground water recharge in the Eastern Desert, Egypt.

    SciTech Connect

    Gheith, H.; Sultan, M.; Environmental Research

    2002-06-10

    We constructed a hydrologic model to estimate the groundwater recharge rate for alluvial aquifers of the Eastern Desert from sporadic precipitation over the Red Sea hills. To estimate initial losses over sub-basins, transmission losses through channel routing, and downstream runoff, we developed an integrated model combining spatial rainfall distribution, an appropriate basin unit hydrograph, and appropriate infiltration parameters. Watersheds and stream networks identified from digital terrain elevation data were verified by comparison with co-registered Landsat thematic mapper scenes and geologic maps. Records of a November 1994 storm event acquired from rain gauges along the Nile River and the Red Sea shore were used to generate a spatial precipitation distribution for the study area. A 2 hour design hyetograph was adopted from rain gauge data for the 1994 flood event. The model was tested against records from the November 1994 flood event at the outlets of the Tarfa and Hammamat watersheds. Groundwater recharge rates were estimated for the alluvial aquifers within the major watersheds of the north Eastern Desert. We estimated that during the 1994 flood event, the ground water recharge through transmission losses ranged from 21 to 31% (Tarfa: 15.8 x 10{sup 6} m{sup 3}; Asyuti: 20 x 10{sup 6} m{sup 3}, Qena: 49 x 10{sup 6} m{sup 3}, Hammamat: 59 x10{sup 6} m{sup 3}) of the precipitated volume. The initial losses ranged from 65 to 77%. Only 3-7% of the precipitation reached the watershed outlets. Archival data show that rainfall events of the size of the November 1994 storm or larger occur every 40 months; thus, the annual recharge rates for the Tarfa, Asyuti, Qena, and Hammamat alluvial aquifers are estimated at 4.7 x 10{sup 6} m{sup 3}, 6 x 10{sup 6} m{sup 3}, 14.7 x 10{sup 6} m{sup 3}, and 17.7 x10{sup 6} m{sup 3}, respectively. Implications for the use of these renewable ground waters and similar water resources in other arid areas of Egypt and in neighboring

  12. Intrinsic and scattering attenuation in the crust of the Abu Dabbab area in the eastern desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, Ali K.; Morsy, M.; El-Hady, Sh.; Kim, K. Y.; Sami, M.

    2008-05-01

    Fifty-five microearthquakes recorded by a digital-temporary seismic network in the Abu Dabbab area in the Eastern Desert of Egypt were used to estimate the direct S-wave ( Qβ), coda ( Qc), intrinsic ( Qi), and scattering quality factors ( Qs). Sato's [Sato H., 1977] single-scattering assumption was used to fit the amplitude envelopes of the coda at seven central frequency bands (1.5, 3, 6, 9, 12, 18, and 24 Hz), obtaining a Qc varying with frequency as generally observed in tectonically active areas. Lapse time dependence was also studied for the area, with the coda waves analyzed at window lengths ranging from 10 to 40 s starting from the onset of the S-wave arrival. The direct S-wave Qβ was estimated using the coda normalization method [Aki, K., 1980a]. The frequency dependence of Q was investigated for the direct S-waves and coda waves. Results show a low quality factor and a high frequency parameter, indicating that the upper lithosphere of the Abu Dabbab area is seismically active and heterogeneous. Using the independent estimates of Qc and Qβ, the intrinsic quality factor Qi was separated from the scattering quality factor. The results suggest that intrinsic dissipation plays a predominant role with respect to scattering phenomena in the area; the obtained Q values seem closer to those reported by analyzing volcano-tectonic earthquakes. This finding reflects that the cause of Abu Dabbab earthquake swarms might be igneous activity where the magma is ascending through joints or serpentinized joints that are dewatering.

  13. Remote sensing detection of gold related alteration zones in Um Rus area, Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Amer, Reda; Kusky, Timothy; El Mezayen, Ahmed

    2012-01-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Phased Array L-band Synthetic Aperture Radar (PALSAR) images covering the Um Rus area in the Central Eastern Desert of Egypt were evaluated for mapping geologic structure, lithology, and gold-related alteration zones. The study area is covered by Pan-African basement rocks including gabbro and granodiorite intruded into a variable mixture of metavolcanics and metasediments. The first three principal component analyses (PCA1, PCA2, PCA3) in a Red-Green-Blue (RGB) of the visible through shortwave-infrared (VNIR + SWIR) ASTER bands enabled the discrimination between lithological units. The results show that ASTER band ratios ((2 + 4)/3, (5 + 7)/6, (7 + 9)/8) in RGB identifies the lithological units and discriminates the granodiorite very well from the adjacent rock units.The granodiorites are dissected by gold-bearing quartz veins surrounded by alteration zones. The microscopic examination of samples collected from the alteration zones shows sericitic and argillic alteration zones. The Spectral Angle Mapper (SAM) and Spectral Information Divergence (SID) supervised classification methods were applied using the reference spectra of the USGS spectral library. The results show that these classification methods are capable of mapping the alteration zones as indicated by field verification work. The PALSAR image was enhanced for fracture mapping using the second moment co-occurrence filter. Overlying extracted faults and alteration zone classification images show that the N30E and N-S fractures represent potential zones for gold exploration. It is concluded that the proposed methods can be used as a powerful tool for ore deposit exploration.

  14. Integration of geophysical and geological data for delimitation of mineralized zones in Um Naggat area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Gaafar, Ibrahim

    2015-06-01

    An integrated approach for geophysical, geological and mineralogical data was followed for Um Naggat area, Central Eastern Desert, Egypt, in order to delineate its mineralized zones. The albitized granites are well-defined on the Th- and U-channel images, by their anomalous shapes, reaching 150 ppm and 90 ppm respectively, beside low K content. Interpretations of the aeromagnetic maps delineated four regional structural trends oriented due NNW, NW, ENE and E-W directions. They are identified as strike-slip faults, which coincide well with field observations, where NW-trending faults cut and displace right laterally ENE-trending older ones. The interaction between these two strike-slip fault systems confining the albite granite is easily identified on the regional data presenting longer wavelength anomalies, implying deep-seated structures. They could represent potential pathways for migration of enriched mineralized fluids. Geochemically, albite granites of peraluminous characteristics that had suffered extensive post-magmatic metasomatic reworking, resulted into development of (Zr, Hf, Nb, Ta, U, Th, Sn) and albite-enriched and greisenized granite body of about 600 m thick, and more than 3 km in strike length. The albite granite is characterized by sharp increase in average rare metal content: Zr (830 ppm), Hf (51 ppm), Nb (340 ppm), Ta (44 ppm), and U (90 ppm). Thorite, uranothorite, uraninite and zircon are the main uranium-bearing minerals of magmatic origin within the enclosing granite. However, with respect to Zr, Nb, and Ta, the albitized granite can be categorized as rare metal granite. The integration of airborne geophysical (magnetic and γ-ray spectrometric), geological, geochemical and mineralogical data succeeded in assigning the albite granite of Um Naggat pluton as a mineralized zone. This zone is characterized by its high thorium and uranium of hydrothermal origin as indicated by its low Th/U ratio, with rare metals mineralization controlled by two

  15. Nutritional parameters and chronic energy deficiency in older adults of desert areas of western Rajasthan, India.

    PubMed

    Arlappa, N; Rao, K Mallikarjuna; Venkaiah, K; Brahmam, G N V; Vijayaraghavan, K

    2009-01-01

    Nutritional status was assessed in 212 older individuals (> or =60 years of age) in a cross - sectional study carried out in desert areas of western Rajasthan during 2003. Heights and weights were recorded and a family diet survey (one-day, 24-hour recall) was carried out in 200 households (HHs) from 20 villages. Body Mass Index (BMI) was used to classify nutritional status. The prevalence of Chronic Energy Deficiency (CED = BMI < 18.5) was > or = 40% in desert areas of India, indicating a "very high" public health problem. It was higher among older women (52%) compared with men (42.4%) and higher in those belonging to Scheduled Caste and Scheduled Tribes and in HHs of laborers, artisans, landless individuals, marginal farmers, and below poverty line families. CED did not differ (statistically) between the desert and plain areas of Rajasthan. CED prevalence among older adults in desert areas was actually lower (p < 0.001) than that found in their rural and tribal counterparts. Intervention programs initiated by the government may explain this finding. Our findings support the conclusion that regular nutritional monitoring of older adults in desert and drought prone areas is needed and can help appropriately target the need for intervention measures. PMID:19234995

  16. Late Neoproterozoic Nuqara Dokhan Volcanics, Central Eastern Desert, Egypt: Geochemistery and petrogenesis

    NASA Astrophysics Data System (ADS)

    Hassan, Tharwat; Asran, Asran; Amron, Taha; Natflos, Theo

    2014-05-01

    The Nuqara volcanic is one of the northernmost outcrops of the Arabian-Nubian Shield Dokhan volcanics. The origin and tectonic setting of the late Neoproterozoic Dokhan volcanics (ca. 610-560 Ma) in the Egyptian Eastern Desert is highly debated. The debate concerns the tectonic setting where they formed during transition between convergent to extensional regime or after the East- and the West-Gondwana collision (~600Ma). In order to solve this problem, lavas from Nuqara area were studied geologically and geochemically. Nuqara Dokhan volcanics comprises two main rock suites: (a) an intermediate volcanic suite, consisting of basaltic andesite, andesite and their associated pyroclastics rocks; and (b) a felsic volcanic suite composed of dacite, rhyolite and ignimbrites. The two suites display well-defined major and trace element trends and continuum in composition with wide ranges in SiO2 (52-75.73%), CaO (9.19-0.22%), MgO (5.29-0.05%), Sr (1367-7.4 ppm), Zr (688.5-172.7 ppm), Cr (207-0.4 ppm), and Ni (94.3-0.2 ppm). The Nuqara Dokhan volcanics are characterized by strong enrichment in LILE relative to HFSE and affiliated to the calc-alkaline subducted - related magmatism. Geochemical Modeling displays that the evolution of these rocks was governed by fractional crystallization of plagioclase, amphiboles, pyroxene, magnetite and apatite in the intermediate varieties and plagioclase, amphibole, magnetite, apatite and zircon in the felsic varieties. The obtained mineral chemistry of these volcanics reveals: (a) Plagioclase range in composition from An55 to An40 in basaltic andesite and from An39 to An24 in andesite. (b) Alkali feldspars have sanidine composition. (c) Clinopyroxenes have augite composition. The low Al2O3 contents (1.94-5.588 wt %) indicate that clinopyroxene crystallized at low - pressure conditions. (d) Amphiboles have magnesio- hornblende composition.

  17. Stratigraphy, sedimentology and tectonic evolution of the Upper Cretaceous/Paleogene succession in north Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El Ayyat, Abdalla M.; Obaidalla, Nageh A.

    2013-05-01

    The stratigraphy, sedimentology and syn-depositional tectonic events (SdTEs) of the Upper Cretaceous/Paleogene (K-P) succession at four localities in north Eastern Desert (NED) of Egypt have been studied. These localities are distributed from south-southwest to north-northeast at Gebel Millaha, at North Wadi Qena, at Wadi El Dakhal, and at Saint Paul Monastery. Lithostratigraphically, four rock units have been recorded: Sudr Formation (Campanian-Maastrichtian); Dakhla Formation (Danian-Selandian); Tarawan Formation (Selandian-Thanetian) and Esna Formation (Thanetian-Ypresian). These rock units are not completely represented all over the study area because some of them are absent at certain sites and others have variable thicknesses. Biostratigrapgically, 18 planktonic foraminiferal zones have been recorded. These are in stratigraphic order: Globotruncana ventricosa Zone (Campanian); Gansserina gansseri, Contusotruncana contusa, Recimguembelina fructicosa, Pseudohastigerina hariaensis, Pseudohastigerina palpebra and Plummerita hantkenenoides zones (Maastrichtian); Praemurica incostans, Praemurica uncinata, Morozovella angulata and Praemurica carinata/Igorina albeari zones (Danian); Igorina albeari, Globanomanlina pseudomenradii/Parasubbotina variospira, Acarinina subsphaerica, Acarinina soldadoensis/Globanomanlina pseudomenardii and Morozovella velascoensis zones (Selandian/Thantian); and Acarinina sibaiyaensis, Pseudohastigerina wilcoxensis/Morozovella velascoensis zones (earliest Ypresian). Sedimentologically, four sedimentary facies belts forming southwest gently-dipping slope to basin transect have been detected. They include tidal flats, outer shelf, slumped continental slope and open marine hemipelagic facies. This transect can be subdivided into a stable basin plain plus outer shelf in the extreme southwestern parts; and an unstable slope shelf platform in the northeastern parts. The unstable slope shelf platform is characterized by open marine hemipelagic

  18. Natural radioactivity and radiation hazard assessment of phosphate mining, Quseir-Safaga area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Gaafar, Ibrahim; El-Shershaby, Amal; Zeidan, Ibrahim; El-Ahll, Lina Sayed

    2016-06-01

    Quseir-Safaga area, Central Eastern Desert, Egypt, includes Duwi Formation, which contains uranium-bearing phosphate beds. The present work used the integrated carborne γ-ray spectrometric data, X-ray analysis and HPGe γ-ray spectrometer data to investigate the radioactive zones at this area. Carborne γ-ray spectrometric survey revealed an increase of equivalent uranium, up to 182 ppm. Maps were drawn to show the results of the three radioelements K, eU, eTh and the eU/eTh ratio. The eU and (eU/eTh) maps reveal that there are twelve important anomalies, associated mainly with phosphate mines. The Hamrawein mines at the northwestern part in the study area seem to represent the highest U-anomalies. Twelve phosphate samples were collected from the determined twelve anomalies. They were analyzed with HPGe detector gamma-ray spectrometer. It was found that the results of radioelement concentrations by carborne survey agree well with that obtained by HPGe. Both of them show that phosphate mines effectively contribute to eU anomalies, occurring in the study area. Meanwhile, 40K, 238U and 232Th concentrations in phosphate samples range from 91 to 169, 864 to 3104 and 28.4 to 106 Bq/kg respectively. The highest concentration of 238U (3104 Bq/kg) occurs in the north of the studied area, close to Hamrawein city. The average concentration of 238U in the analyzed samples is 1766 Bq/kg, which is 53 times higher than the worldwide average value reaching 33 Bq/kg. The highest 232Th concentration value reaching 106 Bq/kg is 2.4 times higher than the worldwide value attaining 45 Bq/kg. The absorbed dose rate for the phosphate samples shows the highest value reaching 1468 nGy/h. This is more than 25 times the worldwide average value 58 nGy/h. The annual effective absorbed dose is also high and reached 1.8 mSv/y, which is about twice higher than the permitted value for public exposure of 1.0 mSv/y. The maximum external hazardous index value of 9.2 is more than nine times the unity

  19. Is the Arabian Nubian Shield with Westward Subduction Polarity? Clues from Prograding Metamorphism in Mantle Peridotites, Eastern Desert of Egypt.

    NASA Astrophysics Data System (ADS)

    Gamal El Dien, H. M.; Abu El-Ela, A. S.; Hamdy, M.; Hassan, A.

    2014-12-01

    Neoproterozoic arc mantle beneath the Arabian Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt exhumed due to intra-oceanic upthrusting are represented mainly by exposed ophiolitic peridotites serpentinized to different degree. Metamorphism is related to the Pan-African collision and the subduction of oceanic lithosphere. However, polarity of the Pan-African intra-oceanic subduction is still questionable. We here trace the variation of the degree of serpentinization and regional metamorphism of six serpentinite masses, widely distributed in the ED (from the east to the west: W (Wadi). Alam, W. Igla, W. Mubarak, G. El-Maiyit, W. Um El Saneyat and W. Atalla). This is based on their mineralogy, textures and mineral chemistry. Much difference in the degree of serpentinization is obvious among these rocks. They are mainly partly serpentinized containing primary olivine and orthopyroxene at W. Alam and W. Igla, while they are completely serpentinized in the other localities. With the increased degree of metamorphism, textures were transformed from the pseudomorphic to the non-pseudomorphic. The most common retrograde assemblage is composed of lizardite _ chrysotile_ brucite_ magnetite. The serpentine prograde textures can be viewed as a continuum from retrograde lizardite pseudomorphic textures, to very fine-grained transitional texture of lizardite and chrysotile, to chrysotile antigorite interlocking texture and finally to antigorite interpenetrating texture. These textures appear to represent successive stages in a recrystallization event. In late subduction-related metamorphism and early collisional emplacement stage, mylonitic-antigorite serpentinites formed and antigorite became the major phase in G. El-Maiyit, Um El-Saneyat andW. Atalla. Compositional zoning in spinel grains in all serpentinites reflect variation in the degree of alteration. The biggest variation of spinel compositions are among serpentinites from Um El-Saneyat and W. Atalla. The alteration

  20. Radioactivity and origin of U-mineralization at the kab Amiri area, central eastern desert, Egypt

    NASA Astrophysics Data System (ADS)

    Abdel-Monem, Abdalla A.; Hussein, H. A.; El-Taher, M. A.; Ammar, Saleh E.

    1994-07-01

    Airborne γ radiometric and spectrometric surveys have shown that the Kab Amiri granite pluton is associated with an aero-γ anomaly of magnitude equivalent to about 4 backgrounds. Detailed field studies including γ spectrometric surveying, sampling, trenching and laboratory investigations revealed the following observations and conclusions. (1) The radioactive anomalies are associated with an episyenitized granite stock exposed to the south of the main pluton. (2) This western contact is controlled by a NW left-lateral major fault and its associated tension fracture systems. (3) The radioactive anomalous zones show many alteration features inclufing muscovitization, sericitization, ferrogenation and carbonatization. (4) The uranium contents range between 16-28 ppm in the non-altered granites, and between 44-169 ppm in the radioactive zones. The Th is very much depleted ranging 1-5.5 ppm with no distribution pattern. (5) The U-deposition is believed to epigenetic since it is associated with the muscovitized and carbonatized episyenite which represent later stages in the episyenitization process itself that is characterized by strong K-leaching.

  1. Integrating geologic and satellite imagery data for high-resolution mapping and gold exploration targets in the South Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem; Emam, Ashraf

    2012-05-01

    The granitoid-greenstone belts of the Arabian-Nubian Shield are well-endowed with lode gold and massive sulfide ores. Although generally characterized by excellent outcrops and arid desert realm, poor accessibility and lack of finance have been always retardant to detailed geologic mapping of vast areas of the shield. Lack of comprehensive geological information and maps at appropriate scales would definitely hinder serious exploration programs. In this study, band ratioing, principal component analysis (PCA), false-color composition (FCC), and frequency filtering (FFT-RWT) of ASTER and ETM+ data have substantially improved visual interpretation for detailed mapping of the Gebel Egat area in South Eastern Desert of Egypt. By compiling field, petrographic and spectral data, controls on gold mineralization have been assessed in terms of association of gold lodes with particular lithological units and structures. Contacts between foliated island arc metavolcanics and ophiolites or diorite are likely to be favorable loci for auriferous quartz veins, especially where the NW-SE foliation is deflected into steeply dipping NNW-trending shear planes. High-resolution mapping of the greenstone belt, structures and alteration zones associated with gold lodes in the study area suggests that dilatation by foliation deflection was related to emplacement of the Egat granitic intrusion, attendant with a sinistral transpression regime (i.e., ˜640-550 Ma?). Gold mineralization associated with granitoid intrusions in transpression-induced pull-apart structures elsewhere in the Eastern Desert (e.g., Fawakhir, Sukari and Hangaliya mines) emphasize the reliability of this setting as a model for gold exploration targets in greenstone terrains of Egypt, and may be elsewhere in the Arabian-Nubian Shield.

  2. Morphodynamic implications for shoreline management of the western-Mediterranean sector of Egypt

    NASA Astrophysics Data System (ADS)

    Frihy, Omran E.

    2009-09-01

    Although the western-Mediterranean coast of Egypt between Sallum and Alexandria, ~550 km long, has maintained a considerable equilibrium throughout history, developers have built traditional protective structures in an effort to form sheltered recreational beaches without taking into consideration its geomorphologic characteristics, coastal processes and their harmful impact on the coastal environment and human safety. The improper practices in this environmentally valuable region have induced us to undertake an initiative to carry out a morphodynamic analysis to provide a framework for understanding the relationship between coastal morphology and the prevailing dynamic forces. Based on the degree of natural protection or wave sheltering, the study shoreline can be categorized into four distinct morphotypical stretches: (1) high-energy wave-exposed shores and the outer margins of the rocky headlands, (2) moderate to high wave-energy beaches along semi-exposed embayments and bays mostly downdrift of the rocky headlands, (3) low-wave energy at semi-exposed headland lee-sided and pocket beaches, and (4) calm wave-sheltered enclosing water basins for safe anchorages, moorings and recreation beaches. The results deducted will have practical applications for shoreline management initiatives regarding sustained sites suitable for future beachfront development such as safe swimming conditions, sport facilities, water intakes and sheltered areas for vessels. In addition, benefits realized by the understanding of the morphodynamic processes would enhance our awareness of the significance of the role of western coast morphodynamics in supporting sustainable development via shoreline management. As far as sustainability is concerned, the selection of appropriate sites would help avoiding or minimizing the formation of the hard structures needed for creating safe recreation beaches. On a national scale, results reached could provide reliable database for information that can be

  3. Pan-African adakitic rocks of the north Arabian-Nubian Shield: petrological and geochemical constraints on the evolution of the Dokhan volcanics in the north Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Obeid, Mohamed A.; Azer, Mokhles K.

    2015-04-01

    The Precambrian basement of Egypt is part of the Red Sea Mountains and represents the north-western part of the Arabian-Nubian Shield (ANS). Five volcanic sections are exposed in the Egyptian basement complex, namely El Kharaza, Monqul, Abu Had, Mellaha and Abu Marwa. They are located in the north Eastern Desert (ED) of Egypt and were selected for petrological and geochemical studies as they represent the Dokhan volcanics. The volcanics divide into two main pulses, and each pulse was frequently accompanied by deposition of immature molasse type sediments, which represent a thick sequence of the Hammamat group in the north ED. Compositionally, the rocks form a continuum from basaltic andesite, andesite, dacite (lower succession) to rhyodacite and rhyolite (upper succession), with no apparent compositional gaps. These high-K calc-alkaline rocks have strong affinities to subduction-related rocks with enriched LILEs (Rb, Ba, K, Th, Ce) relative to high field strength elements (Nb, Zr, P, Ti) and negative Nb anomalies relative to NMORB. The lower succession displays geochemical characteristics of adakitic rocks with SiO2 >53 wt%, Al2O3 >15 wt%, MgO >2.5 wt%, Mg# >49, Sr >650 ppm, Y <17 ppm, Yb <2 ppm, Ni >25 ppm, Cr >50 ppm and Sr/Y >42.4. They also have low Nb, Rb and Zr compared to the coexisting calc-alkaline rhyodacites and rhyolites. The highly fractionated rhyolitic rocks have strong negative Eu anomalies and possess the geochemical characteristics of A-type suites. Trace element geochemical signatures indicate a magma source consistent with post-collisional suites that retain destructive plate signatures associated with subduction zones. The adakitic rocks in the northern ANS are generated through partial melting of delaminated mafic lower crust interacting with overlying mantle-derived magma. The Dokhan volcanics were likely generated by a combination of processes, including partial melting, crystal fractionation and assimilation.

  4. 100 Kyr Old Desert of Western India: Morhodynamics and Environmental Significance

    NASA Astrophysics Data System (ADS)

    Bhatt, N.

    2012-04-01

    The Late Quaternary oscillations in sea levels and resultant changes in the coastal environment have remained a popular aspect of study amongst the earthscientists and archaeologists. The Saurashtra peninsula of the western India that lies on the southwestern side of the Thar Desert, has archived a fascinating record of such environmental changes since last interglacial (~120kyr) in the form of a fossil desert exhibiting various aeolian land forms constituted by the sand largely derived from the coastal areas due to an oscillatory sea level change. A variety of dunes viz., coastal transverse, parabolic, longitudinal, barchans, climbing and falling dunes along with valley fills and sand sheets have been mapped. Being biogenic calcium carbonate rich, the sands have been lithified under the influence of an increase in moisture and thus the dune and bed forms are preserved in its best shape. The intense aeolian activities are also evident in the form of desert varnish on rocky outcrops. The sequence comprises smaller climate perturbations in the form of stabilization, erosion and karstification of older dunes and deposition of fluvial sediments in between. The paper deals with the mode of occurrence, response of sediments to wind dynamics and palaeo topography, internal structures, later modifications of sediments and significance of the geochronologically constrained aeolianites in understanding of environmental changes since 100kyr in the region.

  5. Benefits of protective fencing to plant and rodent communities of the western Mojave Desert, California

    NASA Astrophysics Data System (ADS)

    Brooks, Matthew L.

    1995-01-01

    Human disturbance in the western Mojave Desert takes many forms. The most pervasive are livestock grazing and off-highway vehicle use. Over the past few decades several areas within this region have been fenced to preclude human disturbance. These areas provide opportunities to study the impact of human activities in a desert ecosystem. This paper documents the response of plant and small mammal populations to fencing constructed between 1978 and 1979 at the Desert Tortoise Research Natural Area, Kern County, California. Aboveground live annual plant biomass was generally greater inside than outside the fenced plots during April 1990, 1991, and 1992. The alien grass Schismus barbatus was a notable exception, producing more biomass in the unprotected area. Forb biomass was greater than that of alien annual grasses inside the fence during all three years of the study. Outside the fence, forb biomass was significantly higher than that of alien grasses only during spring 1992. Percent cover of perennial shrubs was higher inside the fence than outside, while no significant trend was detected in density. There was als more seed biomass inside the fence; this may have contributed to the greater diversity and density of Merriam's kangaroo rats ( Dipodomys merriami), long-tailed pocket mice ( Chaetodipus formosus), and southern grasshopper mice ( Onychomys torridus) in the protected area. These results show that protection from human disturbance has many benefits, including greater overall community biomass and diversity. The significance and generality of these results can be further tested by studying other exclosures of varying age and configurations in different desert regions of the southwestern United States.

  6. Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abdeen, Mamdouh M.; Greiling, Reinhard O.; Sadek, Mohamed F.; Hamad, Sayed S.

    2014-11-01

    dykes dissecting it, the highest susceptibilities exceed 7 × 10-2 SI units in magnetite-bearing serpentinite. Early orogenic rocks are characterized by relatively high anisotropies (P‧ up to 1.7) and are deformed in numerous shear zones. Most of these shear zones can be related to the Najd Fault System. In contrast, late orogenic sediments and intrusives show mostly low anisotropies. However, magnetic lineations are still distinctly oriented parallel with the Najd Fault trend. The very latest Pan-African intrusives, the broadly N-S trending dykes crosscutting the Kadabora pluton, imply c. E-W directed extension. Such an extension is consistent with the magnetic fabric in some of the dykes. Therefore, the Kadabora dykes mark the end of Najd wrenching and a late stage of extension in this part of the Eastern Desert of Egypt. The other dykes display mostly primary fabrics, related to magma flow during their intrusion and are thus post-deformational with regard to the Pan-African orogeny.

  7. Study of natural radioactivity and the state of radioactive disequilibrium in U-series for rock samples, North Eastern Desert, Egypt.

    PubMed

    El-Dine, Nadia Walley

    2008-01-01

    Twenty rock samples collected from North Eastern Desert in Egypt have been investigated. Natural radionuclide contents have been measured by gamma-ray spectrometry employing a shielded HPGe detector. The activities of (238)U, (232)Th and (40)K have been determined in Bq/kg dry weight. The absorbed dose rate of gamma radiation ranged from 100.48 to 22,140.53 nGy/h. The representative external hazard index values (H(ex)) for the corresponding samples were estimated. In the present work, the state of radioactive disequilibrium in the U-series at Wadi Baligh area was studied. The activity ratios between (226)Ra/(214)Pb and (214)Pb/(214)Bi were measured. The thorium-to-uranium concentration ratios (Clark value) were also estimated. PMID:17869529

  8. Remote sensing based improvement of the geological map of the Neoproterozoic Ras Gharib segment in the Eastern Desert (NE-Egypt) using texture features

    NASA Astrophysics Data System (ADS)

    Jakob, Sandra; Bühler, Benjamin; Gloaguen, Richard; Breitkreuz, Christoph; Eliwa, Hassan Ali; El Gameel, Khaled

    2015-11-01

    Geological mapping in the Eastern Desert is impeded by difficult accessibility. We improve the existing geological maps by including texture features in a classification scheme of ASTER and Landsat 8 data. We tested the improvement of support vector machine classification using band ratios, principal component analysis (PCA) and texture analysis in the Ras Gharib segment (NE Egypt). A very high classification overall accuracy of 99.85% was achieved. We demonstrate that the input of textures provide valuable additional data for lithological mapping. With the gained information, the existing geological map of the study area was improved distinctly in precision and resolution, but also in terms of correction of yet wrong or inaccurate locations and of lithological unit extents.

  9. Environmental pollutant isotope measurements and natural radioactivity assessment for north Tushki area, south western desert, Egypt.

    PubMed

    Sroor, A; Afifi, S Y; Abdel-Haleem, A S; Salman, A B; Abdel-Sammad, M

    2002-09-01

    Natural radioactive materials under certain conditions can reach hazardous radiological levels. The natural radionuclide (238U, 232Th, 40K) contents of rock samples at various locations in the North Tushki area were investigated using gamma-spectrometric analysis. Estimates of the measured radionuclide content have been made for the absorbed dose rate of gamma radiation. The equivalent radium (Req) and the external hazard index (Hex) which resulted from the natural radionuclides in soil are also calculated and tabulated. The studied samples have been collected from various rock exposures in the North Tushki area. The distribution of major oxides, U and Th were studied. It is found that the enrichment and depletion of the major oxides are mainly due to the effect of hydrothermal alteration, which caused mobility of some major oxides, which increases some elements and decreases others. It is important to mention that the study area is far from the development region of the Tushki project and is only a local hazard. Therefore, additional regional studies of the Tushki Project area should be under taken to explore any unexpected environmental hazard due to the high concentration of the radioactive elements, which have been observed at its north boundary. PMID:12201151

  10. Prospect evaluation of BED 3 and Sitra oilfields, Abu Gharadig Basin, North Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Ibrahim; Ghazala, Hosni; El Diasty, Waleed

    2015-12-01

    The occurrence of hydrocarbons is closely linked to the elements of petroleum system history of the BED 3 and Sitra 8 oilfields, which has created multiple reservoir and seal combinations. BED 3 Field and Sitra concessions occupy the northwestern part of the Abu Gharadig Basin and extends between latitudes 29°45‧ and 30°05‧N and longitudes 27°30‧ and 28°10‧E. The comprehensive integration of the geo-related data and the interpretation of the well logging, geochemical, seismic data in time domain and depth and sealing mechanisms explain the occurrence of hydrocarbons in some certain reservoirs during cretaceous age and other reservoirs in the same fields don't have any hydrocarbon accumulation. Detailed seismic data interpretation was performed for the target units of BED 3 and Sitra 8 oilfields in time domain and converted to depth domain. Sitra 8 Field is a three-way dip closure bounded by NW-SE faults while BED 3 field is represented by a WNW-ESE trending horst dipping to the east. The Albian-Cenomanian Kharita Formation has a high energy shallow marine shelf environment and considered as the main pay zone in the BED 3 oilfield. On the other hand, Kharita sands are dry in the Sitra 8 Field. Also, the shallow marine shale, sandstone, limestone and dolomite interbeds of the Abu Roash G Member are another hydrocarbon bearing reservoir in the Sitra 8 Field. Sealing mechanisms were applied to explain why certain reservoirs have hydrocarbon and others don't. Allan's juxtaposition diagram for the main faults in the study area shows that Kharita sands in BED 3 area have excellent juxtaposition as Kharita juxtapose to upper Bahariya and intra Bahariya, which consist of shale and limestone. Abu Roash G sands in BED 3 area have bad juxtaposition as the Abu Roash G juxtapose to Abu Roash C sand (sand juxtaposed sand). Allan's diagram shows that the Abu Roash G reservoir (main target) in Sitra 8 is juxtaposing Abu Roash D which is composed of limestone and shale, which acts as very good seal rock, while the Kharita reservoir is juxtaposing Abu Roash G sand (sand juxtaposed sand) from the crest position which can explain the bad juxtaposition.

  11. Human Impact On Landscape And The Revenue In Wadi El Rayan Western Desert Egypt

    NASA Astrophysics Data System (ADS)

    Asayed El Gammal, El

    2010-05-01

    Wadi El-Rayan depression occupy about 1800 Km2, it lies in 170 km southwest Cairo. Two lakes in El-Rayan depression initiated since 1973 in a big project when people inundate with excess agricultural sewage water. This article aim to estimate the landscape's response and it's revenue to human's intervention. Two new geomorphological maps, before and after the lakes prepared in the field to understand the landscape changes and its characteristics. Water fluctuation in El Rayan Lakes required multitemporal Landsat image. Geomorphological landforms disappeared and others initiated and neo-ecosystem had been generated. Active elongated sand dune fields covered by water and the dune pattern changed from straight-linear pattern to braided pattern and sand sheets delineating that linear dunes lost activity. Hence avoid and avert dune‘s hazards on the agriculture west of Nile Valley. Landforms and geologic heritage demonstrated that there is an old lake under El Rayan depression. The artificial lakes lead to rise the water table which may abut attempts to utilize from the underground water my stored and water from artificial lakes may infiltrate and contaminate this water. The water volume changed in the southern lake from 501,2 km³ at 1984 to 1097,4 km³ at 1999.

  12. Application of LANDSAT satellite imagery for iron ore prospecting in the western desert of Egypt

    NASA Technical Reports Server (NTRS)

    Elshazly, E. M.; Abdel-Hady, M. A.; Elghawaby, M. A.; Khawasik, S. M. (Principal Investigator)

    1977-01-01

    The author has identified the following significant results. The delineation of the geological units and geological structures through image interpretation, corroborated by field observations and structural analysis, led to the discovery of new iron ore deposits. A new locality for iron ore deposition, namely Gebel Qalamun, was discovered, as well as new occurrences within the already known iron ore region of Bahariya Oasis.

  13. Near eastern neolithic genetic input in a small oasis of the Egyptian Western Desert.

    PubMed

    Kujanová, Martina; Pereira, Luísa; Fernandes, Verónica; Pereira, Joana B; Cerný, Viktor

    2009-10-01

    The Egyptian Western Desert lies on an important geographic intersection between Africa and Asia. Genetic diversity of this region has been shaped, in part, by climatic changes in the Late Pleistocene and Holocene epochs marked by oscillating humid and arid periods. We present here a whole genome analysis of mitochondrial DNA (mtDNA) and high-resolution molecular analysis of nonrecombining Y-chromosomal (NRY) gene pools of a demographically small but autochthonous population from the Egyptian Western Desert oasis el-Hayez. Notwithstanding signs of expected genetic drift, we still found clear genetic evidence of a strong Near Eastern input that can be dated into the Neolithic. This is revealed by high frequencies and high internal variability of several mtDNA lineages from haplogroup T. The whole genome sequencing strategy and molecular dating allowed us to detect the accumulation of local mtDNA diversity to 5,138 +/- 3,633 YBP. Similarly, theY-chromosome gene pool reveals high frequencies of the Near Eastern J1 and the North African E1b1b1b lineages, both generally known to have expanded within North Africa during the Neolithic. These results provide another piece of evidence of the relatively young population history of North Africa. PMID:19425100

  14. Water Management Strategy in Assessing the Water Scarcity in Northern Western Region of Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Mabrouk, Badr; Arafa, Salah; Gemajl, Khaled

    2015-04-01

    Sustainable development in the Nile Delta of Egypt is retarded by serious environmental problems, where land-use and land-cover of the region are subjected to continuous changes; including shoreline changes either by erosion or accretion, subsidence of the delta, as well as by sea level rise due to climate change. The current research attempts to; (1) study the vulnerability of the northern western region of the Nile Delta coastal zone to climate change/sea level rise while setting basic challenges, review adaptation strategies based on adaptation policy framework, and highlight recommended programs for preparedness to climate change, (2) study the scarcity of water resources in the area of study with review of the socioeconomic impacts and the critical need of establishing desalination plants with new standards assessing the environmental situation and population clusters, and (3) monitor of the brine water extracted from the desalination plants and injected to subsurface strata. This monitoring process is divided into 3 main directions: 1) studying the chemical characteristics of water extracted from the water desalinations plants qualitatively and quantitatively. 2) mapping the subsurface of which that brine water will be injected to it and the flow directions and effects using resistivity data, and 3) using GIS and suitable numerical models in order to study the effect, volume, flow of the brine water and its long term environmental impacts on the area. The results indicate that the area is particularly vulnerable to the impact of SLR, salt water intrusion, the deterioration of coastal tourism and the impact of extreme dust storms. This in turn will directly affect the agricultural productivity and human settlements in coastal zones. The paper presents different scenarios for water management and recommends the most suitable scenarios in order to establish a core for water management strategy in the region according to existing socio-economic and environmental

  15. Western blot can distinguish natural and acquired antibodies to Mycoplasma agassizii in the desert tortoise (Gopherus agassizii).

    PubMed

    Hunter, Kenneth W; Dupré, Sally A; Sharp, Tiffanny; Sandmeier, Franziska C; Tracy, C Richard

    2008-12-01

    Mycoplasma agassizi has been identified as a cause of upper respiratory tract disease (URTD) in the threatened Mojave population of the desert tortoise (Gopherus agassizii), and anti-M. agassizii antibodies have been found by ELISA in as many as 15% of these animals across their geographic range. Here we report that a cohort of 16 egg-reared desert tortoises never exposed to M. agassizii had ELISA antibody titers to this organism that overlapped with titers obtained from some M. agassizii-infected tortoises. These natural antibodies were predominantly of the IgM class. Western blots of plasma from these non-infected tortoises produced a characteristic banding pattern against M. agassizii antigens. A group of 38 wild-caught desert tortoises was tested by ELISA, and although some of these tortoises had antibody titers significantly higher than the non-infected tortoises, there was considerable overlap at the lower titer levels. However, Western blot analysis revealed distinct banding patterns that could readily distinguish between the non-infected tortoises and tortoises with acquired antibodies, regardless of ELISA antibody titers. We conclude that desert tortoises have natural antibodies to M. agassizii that can compromise the determination of infection status by ELISA. However, the Western blot technique can distinguish between natural and acquired antibody patterns and can be used to confirm the diagnosis of M. agassizii infections in the desert tortoise. PMID:18708096

  16. Habitat invasibility and dominance by alien annual plants in the western Mojave Desert

    USGS Publications Warehouse

    Brooks, M.L.

    1999-01-01

    Patterns of habitat invasibility and alien dominance, respectively measured as species richness and biomass of alien annual plants, were evaluated in association with four habitat factors at the Desert Tortoise Research Natural Area (DTNA) in the western Mojave Desert, USA. Habitat factors varied in levels of disturbance outside (high) and inside (low) the DTNA, and in levels of soil nutrients in washlet (high) and hummock (low) topographic positions, in Larrea-north (high), Larrea-south (medium), and interspace (low) microhabitats near creosote bushes (Larrea tridentata), and during 1995 when rainfall was 207% (high) and 1994 when rainfall was 52% (low) of the long-term average. Dominant alien plants included the annual grasses Bromus rubens, Bromus trinii, and Schismus spp., and the forb Erodium cicutarium. Species richness and dominance of alien annual plants were slightly higher where disturbance was high, and much higher where soil nutrients were high. B. rubens and B. trinii were most dominant in washlets and in the Larrea-north microhabitats during both years. These two species evolved in mesic ecosystems, and appeared to be particularly limited by soil nutrients at this site. Schismus spp. and E. cicutarium were also most dominant in washlets, but their dominance varied between interspaces in 1994 and the Larrea-south microhabitat in 1995. Monitoring to detect the invasion of new annual plants should focus on regions of high rainfall and nitrogen deposition and on washes and beneath-canopy microhabitats. The ecological range of each alien species should be evaluated separately, because their evolutionary origins may greatly affect their patterns of invasion and dominance in the Mojave Desert.

  17. Prospecting cold deserts of north western Himalayas for microbial diversity and plant growth promoting attributes.

    PubMed

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Saxena, Anil Kumar

    2015-06-01

    Microbial communities in different samples collected from cold deserts of north western Himalayas, India, were analyzed using 16S rRNA gene sequencing and phospholipid fatty acids (PLFA) analysis. A total of 232 bacterial isolates were characterized employing 16S rDNA-Amplified Ribosomal DNA Restriction Analysis with the three restriction endonucleases Alu I, Msp I and Hae III, which led to formation of 29-54 groups for the different sites, adding up to169 groups. 16S rRNA gene based phylogenetic analysis, revealed that 82 distinct species of 31 different genera, belonged to four phyla Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. PLFA profiling was performed for concerned samples which gave an estimate of microbial communities without cultivating the microorganisms. PLFA analysis led to characterization of diverse group of microbes in different samples such as gram-negative, gram-positive bacteria, actinomycetes, cyanobacteria, anaerobic bacteria, sulphate reducing bacteria and fungi. The representative strains were screened for their plant growth promoting attributes, which included production of ammonia, HCN, gibberellic acid, IAA and siderophore; solubilization of phosphorus and activity of ACC deaminase. In vitro antifungal activity assay was performed against Rhizoctonia solani and Macrophomina phaseolina. Cold adapted microorganisms may serve as inoculants for crops growing under cold climatic conditions. To our knowledge, this is the first report for the presence of Arthrobacter nicotianae, Brevundimonas terrae, Paenibacillus tylopili and Pseudomonas cedrina in cold deserts and exhibit multifunctional PGP attributes at low temperatures. PMID:25575970

  18. Ecological niche modeling of Coccidioides spp. in western North American deserts.

    PubMed

    Baptista-Rosas, Raúl C; Hinojosa, Alejandro; Riquelme, Meritxell

    2007-09-01

    Coccidioidomycosis is an endemic infectious disease in western North American deserts caused by the dimorphic ascomycete Coccidioides spp. Even though there has been an increase in the number of reported cases in the last years, few positive isolations have been obtained from soil samples in endemic areas for the disease. This low correlation between epidemiological and environmental data prompted us to better characterize the fundamental ecological niche of this important fungal pathogen. By using a combination of environmental variables and geospatially referenced points, where positive isolations had been obtained in southern California and Arizona (USA) and Sonora (Mexico), we have applied Genetic Algorithm for Rule Set Production (GARP) and Geographical Information Systems (GIS) to characterize the most likely ecological conditions favorable for the presence of the fungus. This model, based on environmental variables, allowed us to identify hotspots for the presence of the fungus in areas of southern California, Arizona, Texas, Baja California, and northern Mexico, whereas an alternative model based on bioclimatic variables gave us much broader probable distribution areas. We have overlapped the hotspots obtained with the environmental model with the available epidemiological information and have found a high match. Our model suggests that the most probable fundamental ecological niche for Coccidioides spp. is found in the arid lands of the North American deserts and provides the methodological basis to further characterize the realized ecological niche of Coccidioides spp., which would ultimately contribute to design smart field-sampling strategies. PMID:17395734

  19. Nest site characteristics and nesting success of the Western Burrowing Owl in the eastern Mojave Desert

    USGS Publications Warehouse

    Longshore, Kathleen M.; Crowe, Dorothy E.

    2013-01-01

    We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species.

  20. Bi-Static Deep Electromagnetic Soundings for Martian Subsurface Characterization: Experimental Validation in the Egyptian Western Desert

    NASA Astrophysics Data System (ADS)

    Ciarletti, V.; Le Gall, A.; Berthelier, J. J.; Corbel, Ch.; Dolon, F.; Ney, R.; Reineix, A.; Guiffaud, Ch.; Clifford, S.; Heggy, E.

    2007-03-01

    A bi-static version of the HF GPR TAPIR developed for martian deep soundings has been operated in the Egyptian Western Desert. The study presented focuses on the retrieval of the direction of arrival of the observed echoes on both simulated and measured d

  1. Resilience to disturbance and resistance to alien grass invasions in the cold desert of western North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alien grass invasions are resulting in ecosystem-level transformations of entire landscapes in arid and semi-arid ecosystems. The cold desert of western US is undergoing such a transformation, and is considered one of the most imperiled large ecosystems in the US. To address the rapid and complex ch...

  2. Trace elements assessment in agricultural and desert soils of Aswan area, south Egypt: Geochemical characteristics and environmental impacts

    NASA Astrophysics Data System (ADS)

    Darwish, Mohamed Abdallah Gad; Pöllmann, Hebert

    2015-12-01

    Determination of chemical elements, Al, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, P, Pb, Sc, Sr, Ti, Y, and Zn have been performed in agricultural and desert soils and alfalfa (Medicago sativa) at Aswan area. Consequently, the pollution indices, univariate and multivariate statistical methods have been applied, in order to assess the geochemical characteristics of these elements and their impact on soil environmental quality and plant, and to reach for their potential input sources. The investigation revealed that the mean and range values of all element concentrations in agricultural soil are higher than those in desert soil. Furthermore, the agricultural soil displayed various degrees of enrichment and pollution of Cd, Zn, Mo, Co, P, Ti, Pb. The geochemical pattern of integrated pollution indices gave a clear image of extreme and strong pollution in the agricultural soil stations, their poor quality with high risk to human health and considered as a tocsin for an alert. In contrast, the desert soil is the good environmental quality and safe for plant, animal and human health. Alfalfa is tolerant plant and considered as a biomarker for P and Mo in polluted agricultural soil. Four geochemical associations of analyzing elements in agricultural soil and three ones in desert soil have been generated, and their enhancements were essentially caused by various anthropogenic activities and geogenic sources. The investigation also revealed that the broad extended desert soil is fruitful and promising as cultivable lands for agricultural processes in the futures.

  3. Upper Oligocene evaporites in basin fill of Sevier Desert region, western Utah ( USA).

    USGS Publications Warehouse

    Lindsey, D.A.; Glanzman, R.K.; Naeser, C.W.; Nicholas, D.J.

    1981-01-01

    The basin fill beneath the Sevier Desert of western Utah contains evaporites that were deposited in a broad closed basin. All of the basin fill penetrated by the Gulf Oil 1 Gronning contains abundant volcanic detritus and its alteration products of Cenozoic age. Fission-track dating of tuffaceous sandstone yields ages of 26-28 m.y. Fossil pollen from mudstone in the evaporite-bearing strata includes forms no older than late Oligocene, in good agreement with the fission-track ages. Thus the age of evaporites is late Oligocene and younger. Anhydrite is present throughout approximately 900m of volcaniclastic rocks in the lower part of the section cut by the Gulf hole. Fossil pollen are indicative of an arid to semiarid flora.-from Authors

  4. Desert varnish and environmental change near Broken Hill, Western New South Wales

    NASA Astrophysics Data System (ADS)

    Dragovich, D.

    1988-12-01

    Desert varnish is widespread in arid Australia, and occurs as a thin often discontinuous manganese-enriched surface coating near Broken Hill, western New South Wales. Radiocarbon dating of calcium carbonate associated with this varnish indicated that major varnishing took place before about 10,000 years B.P., with varnish-forming conditions continuing during the Holocene. Small patches of varnish on secondary carbonate, on non-varnished rock and sometimes on existing varnish suggest that current environmental conditions allow for some varnish formation. Loss of varnish has resulted from within-channel abrasion, weathering by lichens, minor breakdown of varnish substrates, and localized weathering, possibly related to a previously higher soil surface.

  5. Interstratified vermiculite-mica in the gneiss-metapelite-serpentinite rocks at Hafafit area, Southern Eastern Desert, Egypt: From metasomatism to weathering

    NASA Astrophysics Data System (ADS)

    Harraz, H. Z.; Hamdy, M. M.

    2010-09-01

    The Hafafit vermiculite in the Southern Eastern Desert of Egypt at the contact of the metapelite and serpentinite rocks with the pegmatites and gneisses of the Hafafit uplift is the only known deposit in the Arabian-Nubian Shield (ANS) rocks of the Eastern Desert (ED). It is distinctively interstratified with mica. The mineralogy and mineral chemistry of this vermiculite at four sites (HV1, HV2, HV3 and HV4) were studied to better understand its origin, which might refers to a specific geologic setting retained to Hafafit area. The vermiculite at Hafafit forms with phlogopite, actinolite-tremolite, asbestos-anthophyllite-talc and talc zones that are arranged from pegmatite and gneisses to the metapelite and serpentinite rocks. These zones were probably formed by metasomatism that related to the intrusion of the granitoid rocks and the connected pegmatites in the upper Pan-African. The XRD and EMPA studies of the interstratified vermiculite-mica concluded that vermiculitization took place through a layer-by-layer transformation of original micas. This formed, in decreasing abundance, mixed-layer phases of biotite/vermiculite (hydrobiotite), phlogopite/vermiculite (hydrophlogopite) and chlorite/vermiculite (corrensite) and discrete phases of vermiculite, chlorite and smectite. A model is suggested, in which chemical weathering by the moving downward meteoric water led to replacement of the interlayer K, in biotite from gneiss and in phlogopite from metasomatic zones, by H 2O molecules, Fe 2+ was oxidized and (OH) - replaced O 2- forming hydrobiotite and hydrophlogopite. By more K remove, Fe was replaced by Mg with the introduction of more layers of H 2O molecules leading to formation of the vermiculite. Weathering formed corrensite mixed-layer and chlorite expandable minerals on the expense of chlorite. Formation of the incomplete smectite-like layers and Al-hydroxy interlayers (13.97 Ǻ) took place at the expense of vermiculite, replacing the Mg interlayer cations

  6. Ground-Water Recharge from Small Intermittent Streams in the Western Mojave Desert, California

    USGS Publications Warehouse

    Izbicki, John A.; Johnson, Russell U.; Kulongoski, Justin T.; Predmore, Steven

    2007-01-01

    Population growth has impacted ground-water resources in the western Mojave Desert, where declining water levels suggest that recharge rates have not kept pace with withdrawals. Recharge from the Mojave River, the largest hydrographic feature in the study area, is relatively well characterized. In contrast, recharge from numerous smaller streams that convey runoff from the bounding mountains is poorly characterized. The current study examined four representative streams to assess recharge from these intermittent sources. Hydraulic, thermal, geomorphic, chemical, and isotopic data were used to study recharge processes, from streamflow generation and infiltration to percolation through the unsaturated zone. Ground-water movement away from recharge areas was also assessed. Infiltration in amounts sufficient to have a measurable effect on subsurface temperature profiles did not occur in every year in instrumented study reaches. In addition to streamflow availability, results showed the importance of sediment texture in controlling infiltration and eventual recharge. Infiltration amounts of about 0.7 meters per year were an approximate threshold for the occurrence of ground-water recharge. Estimated travel times through the thick unsaturated zones underlying channels reached several hundred years. Recharging fluxes were influenced by stratigraphic complexity and depositional dynamics. Because of channel meandering, not all water that penetrates beneath the root zone can be assumed to become recharge on active alluvial fans. Away from study washes, elevated chloride concentrations and highly negative water potentials beneath the root zone indicated negligible recharge from direct infiltration of precipitation under current climatic conditions. In upstream portions of washes, generally low subsurface chloride concentrations and near-zero water potentials indicated downward movement of water toward the water table, driven primarily by gravity. Recharging conditions did not

  7. Chihuahuan Deserts Ecoregion: Chapter 27 in Status and trends of land change in the Western United States--1973 to 2000

    USGS Publications Warehouse

    Ruhlman, Jana; Gass, Leila; Middleton, Barry

    2012-01-01

    The Chihuahuan Desert is the largest of the North American deserts, extending from southern New Mexico and Texas deep into Mexico, with approximately 90 percent of its area falling south of the United States–Mexico border (Lowe, 1964, p. 24). The Chihuahuan Deserts Ecoregion covers approximately 174,472 km2 (67,364 mi2) within the United States, including much of west Texas, southern New Mexico, and a small portion of southeastern Arizona (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is generally oriented from northwest to southeast, with the Madrean Archipelago Ecoregion to the west; the Arizona/New Mexico Mountains, Arizona/New Mexico Plateau, Southwestern Tablelands, and Western High Plains Ecoregions to the north; and the Edwards Plateau and Southern Texas Plains Ecoregions to the east (fig. 1).

  8. Stable-isotope stratigraphy of the Cenomanian-Turonian (Upper Cretaceous) boundary event (CTBE) in Wadi Qena, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Nagm, Emad; El-Qot, Gamal; Wilmsen, Markus

    2014-12-01

    A high-resolution δ13C isotope record from Cenomanian-Turonian boundary interval of shallow marine successions in Egypt is presented. The δ13C curves show the typical features of the globally documented Cenomanian-Turonian positive excursion, including three of the main positive isotope peaks defining the Cenomanian-Turonian Boundary Event (CTBE). Based on high-resolution ammonite biostratigraphy, the CTBE started in the study area above the Late Cenomanian Neolobites vibrayeanus Zone within the Galala Formation, directly above the global sequence boundary Cenomanian 5 (SB Ce 5). A stratigraphic gap at that level cuts out the lower a-peak of the CTBE. The Cenomanian-Turonian boundary is located within the upper part of the positive excursion between carbon excursion peaks c and d, coinciding with the boundary between the Late Cenomanian Vascoceras cauvini and the Early Turonian Vascoceratid zones. The CTBE ended up-section of peak d, at the base of the Choffaticeras spp. Zone. The amplitude of the positive δ13C excursion in Egypt is very high (reaching 6.5‰ vs. V-PDB) and largely matches curves of European standard sections and others localities from different basins. Furthermore, the Lower Turonian Holywell Isotope Event, an important marker within the lowermost Turonian, has tentatively been recognized. The positive carbon stable isotope curves presented herein represent the outreach of the oceanic anoxic event (OAE) 2 in shallow-water nearshore sequences.

  9. An assessment of the external radiological impact in granites and pegmatite in central Eastern Desert in Egypt with elevated natural radioactivity.

    PubMed

    Uosif, M A M; Abdel-Salam, L M

    2011-11-01

    The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples (granite Gabal Ras Barud, Eastern Desert in Egypt) by using gamma spectrometry (NaI (Tl) 3″×3″). The activities of (226)Ra, (232)Th series and (40)K are between (3.8±0.5 and 172.8±1135.1±56.8 8.6), (2.3±0.3 and 103.8±5.2) and (53.1±2.7 and 1135.1±56.8) Bq kg(-1), respectively. With average total annual dose being only 67.2 μSv y(-1), this value is about 6.72 % of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. Geochemical studies revealed that Gabal Ras Barud is formed from a highly fractionated biotite granite, with SiO(2) >75 % and generally enriched in alkali with K/Na >8 %. PMID:21131664

  10. Paleosols of the Upper Cretaceous Lower Tertiary Maghra El-Bahari Formation in the northeastern portion of the Eastern Desert, Egypt: Their recognition and geological significance

    NASA Astrophysics Data System (ADS)

    Wanas, H. A.; Abu El-Hassan, M. M.

    2006-01-01

    The Upper Cretaceous/Lower Tertiary Maghra El-Bahari Formation at Gabal Ataqa and Gabal Shabrawet in the northeastern portion of the Eastern Desert of Egypt is subdivided into two informal lithostratigraphic parts: lower and upper. The lower part has common features of alluvial floodplain-dominated deposits with occasional occurrences of crevasse splay deposits. The upper part has sediments typical of marginal lacustrine environments. Both the floodplain and marginal lacustrine deposits exhibit pedogenic features comprising various types of paleosols. Among other soil-forming processes, diversity in the paleosols studied is mainly attributed to paleoclimatic and paleohydrologic changes. The paleosol criteria suggest two climatic regimes, a subhumid-semiarid one succeeded by a semiarid-arid one. The continental depositional environments recognized (floodplain and lacustrine) with their associated paleosols helped in the recognition of a marine regression in the area studied. In a regional perspective, comparison of the data presented in this study with paleosol data spanning the same time period in other localities suggests that the proposed paleoclimatic changes may have been of regional extent.

  11. The distribution of radioelements in El Gluf biotite granite, north Eastern Desert, Egypt: a guide to the recognition of anomalously radioactive zones

    NASA Astrophysics Data System (ADS)

    Ammar, A. A.; Elkattan, E. M.; Elsadek, M. A.

    1993-05-01

    El-Gluf area is located in the north Eastern Desert of Egypt. It is underlain mainly by Precambrian basement rocks and Phanerozoic sediments. It has been systematically surveyed using high-sensitivity airborne gamma-ray spectrometric and magnetic methods. To identify and outline significant radiometric zones of anomalously high uranium and thorium concentrations in El Gluf biotite granite. These zones could be favourable for potential economic radioactive and/or metallic mineralization. This study could serve as a model for investigating the relationship between the geological structure and radioactive mineralization. Statistical analysis of the gamma-ray spectrometric data were carried out to delineate anomalies. A two-dimensional trend analysis of faults as tracedfrom the geological map, the radiometric gradients, magnetic lineations and the courses of wadis (valleys) were carried out to delineate major and minor trends in the area. Seven spectrometric anomalies (two pure uranium, two pure thorium, and three mixed) could be related to the prevailing faulting directions: N-S, N-W and NE. The NW and NE fault trends proved to have a significant impact on the localization of radiometric anomalies, which may point to potential and structurally controlled uranium and thorium mineralizations whose structures are considered to have acted as channel ways for the mineralized solutions.

  12. Finite strain analysis of metavolcanics and metapyroclastics in gold-bearing shear zone of the Dungash area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Kassem, Osama M. K.; Abd El Rahim, Said H.

    2014-11-01

    The Dungash gold mine area is situated in an EW-trending quartz vein along a shear zone in metavolcanic and metasedimentary host rocks in the Eastern Desert of Egypt. These rocks are associated with the major geologic structures, which are attributed to various deformational stages of the Neoproterozoic basement rocks. Field geology, finite strain and microstructural analyses were carried out and the relation-ships between the lithological contacts and major/minor structures have been studied. The R f/ϕ and Fry methods were applied on the metavolcano-sedimentary and metapyroclastic samples from 5 quartz veins samples, 7 metavolcanics samples, 3 metasedimentary samples and 4 metapyroclastic samples in Dungash area. Finite-strain data show that a low to moderate range of deformation of the metavolcano-sedimentary samples and axial ratios in the XZ section range from 1.70 to 4.80 for the R f/ϕ method and from 1.65 to 4.50 for the Fry method. We conclude that finite strain in the deformed rocks is of the same order of magnitude for all units of metavolcano-sedimentary rocks. Furthermore, the contact between principal rock units is sheared in the Dungash area under brittle to semi-ductile deformation conditions. In this case, the accumulated finite strain is associated with the deformation during thrusting to assemble nappe structure. It indicates that the sheared contacts have been formed during the accumulation of finite strain.

  13. Zr-Y-Nb-REE mineralization associated with microgranite and basic dykes at EL Sela shear zone, South Eastern Desert, Egypt.

    PubMed

    Shahin, Hassan Abd El-Razek Aly

    2014-01-01

    El Sela shear zone occurs in the younger granite rock of Gabal El Sela area, south Eastern Desert, Egypt near the Sudan Frontier. It comprises lines-arranged intrusions trending ENE-WSW and extend for about 1.5 km in length and reach up to 40 meters in width. These lines-arranged intrusions include multi-phase quartz veins, altered microgranite and altered basic dykes. These dykes hosting or acting as a source for uranium, rare metals (Zr, Y, Nb and Ga) and light rare earths (La, Ce, Sm and Nd) mineralizations. They show highly alteration, uranium enrichment and a strong enrichment in some rare metals and light rare earths contents (Zr = 644, Y = 133, Nb = 136, Ga =184, La = 50.19, Ce = 105.47, Sm = 24.81, Nd = 78.91 ppm and and ∑ LREEs = 259.38.). The chondrite normalised rare earth elements trends indicate strongly fractionated rare earth elements pattern with significant enriched of LREE according to HREE in both altered microgranite and altered basic dykes. Field radiometric measurements of the studied altered microgranite dyke revealed that eU reach up to 359 ppm with an average 78 ppm, while in the altered basic dyke reach up to 1625 ppm with an average 144 ppm. PMID:25332873

  14. Thermodynamic modelling of Sol Hamed serpentinite, South Eastern Desert of Egypt: implication for two serpentinization stages in the Arabian-Nubian Shield ophiolites

    NASA Astrophysics Data System (ADS)

    Abu-Alam, T.; Hamdy, M.

    2012-04-01

    The Arabian-Nubian Shield is the largest tract of juvenile continental crust of Neoproterozoic age on Earth. This crust was generated due to arc-arc collision associated with the closing of the Mozambique Ocean. Distribution of ophiolitic rocks marks fossils suture zones in the shield. Petrological, mineral chemistry, whole-rock chemistry and thermodynamic studies are carried out to examine the serpentinite component of Sol Hamed ophiolite in south Eastern Desert of Egypt. The protolith mantle was harzburgite and formed in subduction zone of forearc setting. Serpentinization occurred in two stages. The first by intrusion of high concentrated CO2 fluid released from carbonate-bearing sediments and altered basalt at the subduction zone. The serpentinization achieved during isobaric cooling path at pressure of 1 kbar and before the emplacement. The minimum temperature limit of the serpentinization is above the breakdown of lizardite to antigorite and brucite (170 °C). The fluid composition during the isobaric cooling path was buffered by the metamorphic reactions. The second stage of serpentinization took place through prograde path which led to formation of chrysotile after lizardite. The increasing in the pressure during this stage occurred as a result of extensive duplex array and thrusting of oceanic crust. The crust in the forearc basin was overloaded by 28 km of obducted and thrusted oceanic crust from both mid-oceanic and forearc basins, respectively.

  15. Petrology of the Motaghairat mafic-ultramafic complex, Eastern Desert, Egypt: A high-Mg post-collisional extension-related layered intrusion

    NASA Astrophysics Data System (ADS)

    Abdel Halim, Ali H.; Helmy, Hassan M.; Abd El-Rahman, Yasser M.; Shibata, Tomoyuki; El Mahallawi, Mahmoud M.; Yoshikawa, Masako; Arai, Shoji

    2016-02-01

    The geodynamic settings of the Precambrian mafic-ultramafic complexes in the Eastern Desert of Egypt have important bearing on understanding the geotectonic evolution of the Arabian Nubian Shield. We present a detailed petrological study on a layered mafic-ultramafic intrusion that is located at the contact between the Precambrian continental crust and the Miocene Red Sea oceanic crust. The Motaghairat layered intrusion consists of basal lherzolite, orthopyroxenite, troctolite, olivine gabbro and anorthosite on the top. Variations in modal mineralogy and mineral chemistry along with the chemical composition of these units suggest their derivation from a common high-Mg tholeiitic parent melt through fractional crystallization processes. The parental magma was derived from a metasomatised mantle source. The primitive mantle-normalized patterns of the calculated melts exhibit enrichment in U relative to Th and Ba relative LREE which indicate that the enriched lithospheric mantle source was metasomatised by fluids derived from a subducted oceanic crust rather than by a sediment melt. Geological and petrological evidences suggest that the layered Motaghairat intrusion was emplaced during post-orogenic extension following subduction break-off and lithospheric delamination after the collision between the amalgamated island arc terranes and the Saharan Metacraton. The heat source required to melt the metasomatised lithospheric mantle was derived from the upwelling of hot asthenosphere after the subduction-break-off.

  16. Neoproterozoic diamictite in the Eastern Desert of Egypt and Northern Saudi Arabia: evidence of ~750 Ma glaciation in the Arabian-Nubian Shield?

    NASA Astrophysics Data System (ADS)

    Ali, Kamal A.; Stern, Robert J.; Manton, William I.; Johnson, Peter R.; Mukherjee, Sumit K.

    2010-06-01

    The Neoproterozoic Atud diamictite in Wadi Kareim and Wadi Mobarak in the Eastern Desert of Egypt and the Nuwaybah formation in NW Saudi Arabia consist of poorly sorted, polymictic breccia, with clasts up to 1 m of granitoid, quartz porphyry, quartzite, basalt, greywacke, marble, arkose, and microconglomerate in fine-grained matrix. Stratigraphic relations indicate that the diamictite was deposited in a marine environment. Integrated field investigation, petrographic study and U-Pb SHRIMP zircon ages demonstrate that the Atud and Nuwaybah are correlative. The distribution of zircon ages indicate that ~750 Ma ages are dominant with a significant component of older materials, characterized by minor Mesoproterozoic and more abundant Paleoproterozoic and Neoarchean ages. Some matrix and metasedimentary clast zircons yield ages that are a few 10s of Ma younger than the age of the youngest clast (754 ± 15 Ma), suggesting Atud/Nuwaybah diamictite deposition ~750 Ma or slightly later, broadly consistent with being deposited during the Sturtian glaciation (740-660 Ma). The Paleoproterozoic and Neoarchean clasts have no source within the ensimatic Arabian-Nubian Shield. The distribution of the pre-Neoproterozoic ages are similar to the distribution of the pre-Neoproterozoic ages in Yemen and Saharan Metacraton, suggesting that these clasts have been transported hundreds of kilometers, maybe by ice-rafting. The Atud diamictite may represent important evidence for Cryogenian “Snowball Earth” in the Arabian-Nubian Shield.

  17. Upper Oligocene evaporites in basin fill of Sevier Desert region, western Utah

    SciTech Connect

    Lindsey, D.A.; Glanzman, R.K.; Naeser, C.W.; Nichols, D.J.

    1981-02-01

    The basin fill beneath the Sevier Desert of western Utah contains evaporites of late Oligocene age that were deposited in a broad closed basin. All of the basin fill penetrated by the Gulf Oil 1 Gronning (2458 m TD), one of only three deep holes in the basin, contains abundant volcanic detritus and its alteration products of Cenozoic age, when volcanism was intense in western Utah. Fission-track dating of tuffaceous sandstone, interbedded with evaporite minerals and representative of sandstone in the lower formations penetrated, yields ages of 26 to 28 m.y.; concordance of ages indicates no thermal resetting. Fossil pollen from mudstone in the evaporite-bearing strata includes forms no older than late Oligocene, in good agreement with the fission-track ages. Thus the age of the evaporites, and of all the basin fill penetrated by drilling, is late Oligocene and younger; previous work had assigned them ages ranging from Triassic to Eocene. Evaporite-bearing rocks were deposited during late Oligocene time in a broad closed basin under arid or semiarid conditions much like those of the Great Basin today. Anhydrite is present throughout approximately 900 m of volcaniclastic rocks in the lower part of the section cut by the Gulf hole, and more than 1500 m of anhydrite and halite is present in possibly equivalent strata in the nearby Argonaut dry hole. Fossil pollen from anhydrite-bearing rocks in the Gulf hole are indicative of an arid to semiarid flora, including plants similar to Mormon tea and possibly saltbush or buffalo berry. Evaporite minerals formed in the basin during dry periods; tuff was erupted from nearby volcanic centers, reworked by water, and deposited in the basin.

  18. Structural evolution and Cenozoic tectonostratigraphy of the Cairo-Suez district, north Eastern Desert of Egypt: Field-structural data from Gebel Qattamiya-Gebel Um Reheiat area

    NASA Astrophysics Data System (ADS)

    Hagag, Wael

    2016-06-01

    Detailed field mapping reveals that continental rifting is strongly deforming the Gebel Qattamiya-Gebel Um Reheiat area and the entire Cairo-Suez district, in north Eastern Desert of Egypt. Rift-related structures are predominantly represented by E to WNW, NNW and NW oriented faults. The E to WNW oriented faults are small and build up the Gebel Qattamiya en echelon fault belt, whereas the faults trending NNW and NW establish a pervasive horst and graben structural style involving some rhomb-shape horsts as Gebel Qattamiya (GQRH), Gebel Um Reheiat (GURRH) and south Gebel Um Reheiat (SGURRH). Rock units of the Eocene succession and Oligocene sediments are well exposed and highly controlled by rift-related structures. Rifting was developed through two rift-phases; initial and major ones. The initial phase (a newly recognized phase in this contribution) has been occurred in Late Eocene (Priabonian), while the main phase was prevailing during Late Oligocene-Early Miocene time and is characterized by hydrothermal veins and basaltic eruptions. Continental transtension in the Cairo-Suez district, including the study area, was probably synchronous with a major tectonic stage (Pyrenean-Atlasic movement) of continental collision between African-Arabian and Eurasian plates in Late Eocene-Oligocene time. Field investigation suggests that the transfer of displacement (slip) from the Gulf of Suez proto-rift into the E-W oriented faults ''relays'' is an important mechanism, which helps to explain the current structural framework and tectonic evolution of the Cairo-Suez district. Reactivation of such faults with right-lateral divergent wrenching with NE-SW oriented extension deformed the Cairo-Suez district with several E-W oriented en echelon fault belts (e.g. Gebel Qattamiya fault belt in the study area). Thus the Cairo-Suez district represents an accommodation or transfer zone in northeastern Egypt, intercepting the ''far-field stresses'' from the Arabian-Nubian Shield, the Red

  19. Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada. Part I. Geology and geophysics

    SciTech Connect

    Schaefer, D.H.; Welch, A.H.; Maurer, D.K.

    1983-01-01

    Studies of the geothermal potential of the western arm of the Black Rock Desert in northwestern Nevada included a compilation of existing geologic data on a detailed map, a temperature survey at 1-meter depth, a thermal-scanner survey, and gravity and seismic surveys to determine basin geometry. The temperature survey showed the effects of heating at shallow depths due to rising geothermal fluids near the known hot spring areas. Lower temperatures were noted in areas of probable near-surface ground-water movement. The thermal-scanner survey verified the known geothermal areas and showed relatively high-temperature areas of standing water and ground-water discharge. The upland areas of the desert were found to be distinctly warmer than the playa area, probably due to the low thermal diffusivity of upland areas caused by low moisture content. Surface geophysical surveys indicated that the maximum thickness of valley-fill deposits in the desert is about 3200 meters. Gravity data further showed that changes in the trend of the desert axis occurred near thermal areas. 53 refs., 8 figs., 3 tabs.

  20. Recharge to the inter-dune lakes and Holocene climatic changes in the Badain Jaran Desert, western China

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoping; Ma, Nina; Dong, Jufeng; Zhu, Bingqi; Xu, Bing; Ma, Zhibang; Liu, Jiaqi

    2010-01-01

    We present new estimates on evaporation and groundwater recharge in the Badain Jaran Desert, western Inner Mongolia of northwestern China, based on a modified Penman Equation suitable for lakes in China. Geochemical data and water balance calculations suggest that local rainfall makes a significant contribution to groundwater recharge and that past lake-level variations in this desert environment should reflect palaeoclimatic changes. The chronology of lake-level change, established by radiocarbon and U-series disequilibrium dating methods, indicates high lake levels and a wetter climate beginning at ca. 10 ka and lasting until the late mid-Holocene in the Badain Jaran Desert. The greatest extension of lakes in the inter-dune depressions indicates that the water availability was greatest during the mid-Holocene. Relicts of Neolithic tools and pottery of Qijia Culture (2400-1900 BC) suggest relatively intensive human activity in the Badain Jaran Desert during the early and middle Holocene, supporting our interpretation of a less harsh environment. Wetter climates during the Holocene were likely triggered by an intensified East Asian summer monsoon associated with strong insolation.

  1. Effects of protective fencing on birds, lizards, and black-tailed hares in the Western Mojave Desert

    USGS Publications Warehouse

    Brooks, M.

    1999-01-01

    Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA. Nesting activity was also more frequent inside. Total abundance and species richness of lizards and individual abundances of western whiptail lizards (Cnemidophorous tigris) and desert spiny lizards (Sceloporus magister) were higher inside than outside. In contrast, abundance of black-tailed hares was lower inside. Structural diversity of the perennial plant community did not differ due to protection, but cover was 50% higher in protected areas. Black-tailed hares generally prefer areas of low perennial plant cover, which may explain why they were more abundant outside than inside the DTNA. Habitat structure may not affect bird and lizard communities as much as availability of food at this desert site, and the greater abundance and species richness of vertebrates inside than outside the DTNA may correlate with abundances of seeds and invertebrate prey.

  2. Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada; Part I, geology and geophysics

    USGS Publications Warehouse

    Schaefer, Donald H.; Welch, Alan H.; Mauzer, Douglas K.

    1983-01-01

    Studies of the geothermal potential of the western arm of the Black Rock Desert in northwestern Nevada included a compilation of existing geologic data on a detailed map, a temperature survey at 1-meter depth, a thermal-scanner survey, and gravity and seismic surveys to determine basin geometry. The temperature survey showed the effects of heating at shallow depths due to rising geothermal fluids near the known hot spring areas. Lower temperatures were noted in areas of probable near-surface ground-water movement. The thermal-scanner survey verified the known geothermal areas and showed relatively high-temperature areas of standing water and ground-water discharge. The upland areas of the desert were found to be distinctly warmer than the playa area, probably due to low thermal diffusivity resulting from low moisture content. The surface geophysical surveys indicated that the maximum thickness of valley-fill deposits in the desert is about 3,200 meters. Gravity data further showed that changes in the trend of the desert axis occurred near thermal areas. (USGS)

  3. Late Pan-African granite emplacement during regional deformation, evidence from magnetic fabric and structural studies in the Hammamat-Atalla area, Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Greiling, R. O.; de Wall, H.; Sadek, M. F.; Dietl, C.

    2014-11-01

    Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyphase, late Pan-African deformational evolution in the Um Sheqila-Um Had (595 Ma) composite pluton and in the Hammamat and Atalla areas of the Central Eastern Desert of Egypt in Ediacaran times. Major stages are early shortening (NNW-SSE), subsequent strike-slip (NW-SE shear zones), and late shortening (NW-SE). Strain studies on pebbles and xenoliths together with AMS data show a predominance of shallow, NW-SE trending X axes or magnetic lineations, associated with steep, NW-SE striking magnetic foliations. Magnetic fabrics and microstructures indicate a tectonic fabric in the Um Sheqila-Um Had granitoid plutons, which is dominated by steep NW-SE striking foliations and shallow NW-SE trending lineations, similar to those in the high-angle Atalla Shear Zone. There is a change of lineation directions from ESE-WNW at Um Sheqila (oldest) to NW-SE to Um Had II (youngest). This pattern may indicate an influence of strike-slip and is also consistent with NE-SW compression. This holds also true for the asymmetry of the contact aureole, which is extended towards NW, parallel with the trend of the magnetic lineation. The character and orientation of the deformation pattern in the Um Sheqila-Um Had plutons and the Atalla Shear Zone is thus similar to the pattern of the late shortening phase. The intrusion of the Um Sheqila-Um Had granitoid rocks, therefore, took place before the late shortening stage, but postdates early deformation, which, according to published data, was associated with lithospheric thinning in the Central Eastern Desert. Therefore, these Pan-African plutons do not represent the earliest post-deformational intrusions but a late stage of syn-deformational magmatic activity. At a regional scale, this deformation with steep foliations and shallow lineations may also be related with lateral escape tectonics. The pluton emplacement, the importance of transcurrent

  4. Unique chemistry of a diamond-bearing pebble from the Libyan Desert Glass strewnfield, SW Egypt: Evidence for a shocked comet fragment

    NASA Astrophysics Data System (ADS)

    Kramers, Jan D.; Andreoli, Marco A. G.; Atanasova, Maria; Belyanin, Georgy A.; Block, David L.; Franklyn, Chris; Harris, Chris; Lekgoathi, Mpho; Montross, Charles S.; Ntsoane, Tshepo; Pischedda, Vittoria; Segonyane, Patience; Viljoen, K. S. (Fanus); Westraadt, Johan E.

    2013-11-01

    We have studied a small, very unusual stone, here named “Hypatia”, found in the area of southwest Egypt where an extreme surface heating event produced the Libyan Desert Glass 28.5 million years ago. It is angular, black, shiny, extremely hard and intensely fractured. We report on exploratory work including X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy with EDS analysis, deuteron nuclear reaction analysis, C-isotope and noble gas analyses. Carbon is the dominant element in Hypatia, with heterogeneous O/C and N/C ratios ranging from 0.3 to 0.5 and from 0.007 to 0.02, respectively. The major cations of silicates add up to less than 5%. The stone consists chiefly of apparently amorphous, but very hard carbonaceous matter, in which patches of sub-μm diamonds occur. δ13C values (ca. 0‰) exclude an origin from shocked terrestrial coal or any variety of terrestrial diamond. They are also higher than the values for carbonaceous chondrites but fall within the wide range for interplanetary dust particles and comet 81P/Wild2 dust. In step heating, 40Ar/36Ar ratios vary from 40 to the air value (298), interpreted as a variable mixture of extraterrestrial and atmospheric Ar. Isotope data of Ne, Kr and Xe reveal the exotic noble gas components G and P3 that are normally hosted in presolar SiC and nanodiamonds, while the most common trapped noble gas component of chondritic meteorites, Q, appears to be absent. An origin remote from the asteroid belt can account for these features. We propose that the Hypatia stone is a remnant of a cometary nucleus fragment that impacted after incorporating gases from the atmosphere. Its co-occurrence with Libyan Desert Glass suggests that this fragment could have been part of a bolide that broke up and exploded in the airburst that formed the Glass. Its extraordinary preservation would be due to its shock-transformation into a weathering-resistant assemblage.

  5. Processing and interpretation of ASTER TIR data for mapping of rare-metal-enriched albite granitoids in the Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Aboelkhair, Hatem; Ninomiya, Yoshiki; Watanabe, Yasushi; Sato, Isao

    2010-08-01

    ASTER level 1B (radiance at the sensor) TIR-bands and level 2B04 (surface emissivity) data were analyzed to detect four of 14 rare-metal-enriched albite granite, which are classified as I-type magnetite-series (G3 type) granites in the Central Eastern Desert of Egypt. Analysis of the shapes of laboratory emissivity spectrum of albite granite samples measured by portable emission spectrometer and albite mineral spectra from ASTER spectral library at the website of JPL of NASA showed that, albite granite samples has a higher emissivity in bands 12, 13 and 14 than in bands 10 and 11. To identify and map this type of granite, Quartz Index, as well as band ratios, band ratio combination and band combinations were used, based on the shapes of the analyzed emissivity spectrum of albite granite samples and albite mineral. The Quartz Index (QI) was high for quartz-rich/feldspar poor rocks and was low for K-feldspar or gypsum-rich rocks. Albite rich granites were detected as dark pixels in the QI image. The proposed band ratio b12/b11 clearly identified the albite granite bodies as dark regions. False color images of band combination of 14:12:10 and 12:13:11 in R:G:B clearly mapped the albite granite bodies as light brownish yellow and light greenish regions respectively. A new ASTER colored composite band ratio combination b12/b13:b11/b12:b14/b13 as R:G:B is applied successfully for mapping albite granite in the study area. This new combination clearly separated albite granite as pinkish magenta color. An ASTER scene covering the study area acquired on a different date was used to determine the effect of atmospheric and surface temperature conditions on the ratio and the mathematical band operation. The results indicated no significance differences.

  6. Phanerozoic tectonothermal history of the Arabian Nubian shield in the Eastern Desert of Egypt: evidence from fission track and paleostress data

    NASA Astrophysics Data System (ADS)

    Bojar, Ana-Voica; Fritz, Harald; Kargl, Sabine; Unzog, Wolfgang

    2002-05-01

    To constrain the post-Pan-African evolution of the Arabian-Nubian Shield, macro-scale tectonic studies, paleostress and fission track data were performed in the Eastern Desert of Egypt. The results provide insights into the processes driving late stage vertical motion and the timing of exhumation of a large shield area. Results of apatite, zircon and sphene fission track analyses from the Neoproterozoic basement indicate two major episodes of exhumation. Sphene and zircon fission track data range from 339 to 410 Ma and from 315 to 366 Ma, respectively. The data are interpreted to represent an intraplate thermotectonic episode during the Late Devonian-Early Carboniferous. At that time, the intraplate stresses responsible for deformation, uplift and erosion, were induced by the collision of Gondwana with Laurussia which started in Late Devonian times. Apatite fission track data indicate that the second cooling phase started in Oligocene and was related to extension, flank uplift and erosion along the actual margin of the Red Sea. Structural data collected from Neoproterozoic basement, Late Cretaceous and Tertiary sedimentary cover suggest two stages of rift formation. (1) Cretaceous strike-slip tectonics with sub-horizontal σ1 (ENE/WSW) and σ3 (NNW/SSE), and sub-vertical σ2 resulted in formation of small pull-apart basins. Basin axes are parallel to the trend of Pan-African structural elements which acted as stress guides. (2) During Oligocene to Miocene the stress field changed towards horizontal NE-SW extension (σ3), and sub-vertical σ1. Relations between structures, depositional ages of sediments and apatite fission track data indicate that the initiation of rift flank uplift, erosion and plate deformation occurred nearly simultaneously.

  7. Multi-stage emerald formation during Pan-African regional metamorphism: The Zabara, Sikait, Umm Kabo deposits, South Eastern desert of Egypt

    NASA Astrophysics Data System (ADS)

    Grundmann, G.; Morteani, G.

    2008-02-01

    The genesis of gem-quality deep green emeralds of Zabara, Sikait and Umm Kabo (South Eastern Desert, Egypt) is to date a controversial topic. The emerald-bearing biotite schists and quartz lenses are interpreted alternatively as a product of (i) thrust-fault-shear zone - controlled large scale alkali-metasomatism driven by post-magmatic fluid flow or of (ii) a large scale interaction between syntectonic pegmatitic magma or hydrothermal fluids with pre-existing basic to ultrabasic rocks, or of (iii) a syn- to post-tectonic regional metamorphism and small scale blackwall metasomatism. Detailed microstructural and chemical analyses of the Egyptian emeralds and their host rocks show that three generations of beryl can be distinguished: a colourless pegmatitic beryl; a pale green Cr-poor beryl crystallized from pegmatite-related hydrothermal fluids; and a deep green Cr- and Mg-rich emerald. The crystallization of the Cr- and Mg-rich emerald was controlled by the very local availability of Cr, Mg and Be-rich metamorphic fluids during the Pan-African tectono-thermal event. Emerald-rich quartz lenses demonstrate that those fluids locally did mobilize quartz, too. The pale green emeralds found within the pegmatites in association with colourless beryl are the product of a mobilization of colourless pegmatitic beryl and/or phenakite by late pegmatitic fluids slightly enriched in Cr by an interaction with the Cr-rich country rocks. The late pegmatitic fluids are typically Na-rich as is demonstrated by the pervasive albitization of the pegmatites. The complex interplay of magmatic and regional metamorphic events during the genesis of the Egyptian emeralds/beryls makes it impossible through stable oxygen isotope data to relate their genesis to the one or the other event.

  8. Bistatic GPR Measurements in the Egyptian Western Desert - Measured and Simulated data

    NASA Astrophysics Data System (ADS)

    Ciarletti, V.; Le Gall, A.; Berthelier, J.; Ney, R.; Corbel, C.; Dolon, F.

    2006-12-01

    The TAPIR (Terrestrial And Planetary Investigation Radar) instrument has been designed at CETP (Centre d'etude des Environnements Terrestre et Planetaires) to explore the deep Martian subsurface (down to a few kilometers) and to detect liquid water reservoirs. TAPIR is an impulse ground penetrating radar operating at central frequencies ranging from 2 to 4 MHz operating from the surface. In November 2005, an updated version of the instrument working either in monostatic or in bi-static mode was tested in the Egyptian Western Desert. The work presented here focuses on the bi-static measurements performed on the Abou Saied plateau which shows a horizontally layered sub-surface. The electromagnetic signal was transmitted using one of the two orthogonal 70 m loaded electrical dipole antennas of the transmitting GPR. A second GPR, 50 or 100 meters apart, was dedicated to the signal reception. The received waves were characterized by a set of 5 measurements performed on the receiving GPR : the two horizontal components of the electric field and the three composants of the magnetic field. They were used to compute the direction of arrival of the incoming waves and to retrieve more accurately their propagation path and especially to discriminate between waves due to some sub-surface reflecting structure and those due to interaction with the surface clutter. A very efficient synchronization between the two radars enabled us to perform coherent additions up to 2^{31} which improves dramatically the obtained signal to noise ratio. Complementary electromagnetic measurements were conducted on the same site by the LPI (Lunar and Planetary Institute) and the SwRI (Southwest Research Institute). They provided independent information which helped the interpretation of the TAPIR data. Accurate simulations obtained by FDTD taking into account the information available are presented and used for both the interpretation of the measured data and the validation of the instrument.

  9. Sex pheromone of the saturniid moth, Hemileuca burnsi, from the western Mojave Desert of California.

    PubMed

    McElfresh, J Steven; Millar, Jocelyn G

    2008-09-01

    The sex pheromone blend of Hemileuca burnsi (Lepidoptera: Saturniidae) from the western Mojave Desert was determined to be a combination of (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), and hexadecyl acetate (16:Ac). (10E,12Z)-Hexadecadienal (E10,Z12-16:Ald) was tentatively identified in pheromone gland extracts based on electroantennographic responses and, when added to the above blend, it enhanced trap captures at low doses. The mean ratio of the compounds in extracts of pheromone glands was 100:23:232:14:0.4 (E10,Z12-16:Ac: E10,E12-16:Ac: 16:Ac: E10,Z12-16:OH: E10,Z12-16:Ald). Field trials indicated that although E10,Z12-16:Ac and E10,Z12-16:OH were essential for attraction, the two-component blend was not attractive by itself. Addition of the three other compounds was necessary for maximum attraction, rendering this the most complicated pheromone blend described for a Hemileuca species to date. Similarities between the sex pheromone of H. burnsi and that of the allopatric Hemileuca electra electra and differences between the blends of H. burnsi and that of the sympatric H. electra mojavensis support a case for reproductive character displacement in the pheromone communication channel of H. electra. PMID:18649103

  10. Evaluation of heat generation by radioactive decay of sedimentary rocks in Eastern Desert and Nile Valley, Egypt.

    PubMed

    Abbady, Adel G E

    2010-10-01

    Radioactive heat-production (RHP) data of sedimentary outcrops in Gebel Anz (Eastern Desert) and Gebel Sarai (Nile Valley) are presented. A total of 103 rock samples were investigated, covering all major rock types of the areas. RHP were derived from uranium, thorium and potassium concentrations measured from gamma-radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K, obtained with a NaI (Tl) detector. The heat-production rate of Gebel Anz ranges from 0.94 (Nubai Sandstone ) to 5.22 microW m(-3) (Duwi Formation). In Gebel Sarai it varies from 0.82 (Esna Shale) to 7 microW m(-3) (Duwi Formation). The contribution due to U is about 62%, from Th is 34% and 4% from K in Gebel Anz. The corresponding values in Gebel Sarai are 69.6%, 26.9% and 3.5%, respectively. These data can be used to discuss the effects of the lateral variation of the RHP rate on the heat flux and the temperature fields in the upper crust. PMID:20472452

  11. Holocene freshwater carbonate structures in the hyper-arid Gebel Uweinat region of the Sahara Desert (Southwestern Egypt)

    NASA Astrophysics Data System (ADS)

    Marinova, Margarita M.; Meckler, A. Nele; McKay, Christopher P.

    2014-01-01

    The eastern part of the Sahara is at present the driest region of the desert. Yet the extensive animal rock art in the area, presumed to depict real activities in the lives of the painters, suggests that environmental conditions were significantly different when the rock art was produced. Here we report on exploration of the area, which led to the discovery of morphologically-distinct carbonate structures that line the walls of two valleys in Gebel Uweinat, and were likely formed in standing water. The carbonate structures comprise what appear to be shoreline carbonate formations, and date back to 8100 and 9400 years BP. The chemical and morphological similarity of these formations to carbonate structures from modern lakes suggests that these lakes contained fresh, standing water suitable for human and animal use. However, the significant quartz content suggests that windblown sand was pervasive, and thus the vegetation cover may have been sparse. This discovery supports the possibility of grasslands in the area, which may have been able to support human habitation, and adds to the evidence for a wetter climate in the area in the early Holocene.

  12. Radioactivity and distribution of U and Th in some granitic masses, Wadi El-Saqia Area, Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Abdel-Monem, A. A.; Hussein, H. A.; Abdel-Kader, Z. M.; Abu Zied, H. T.; Ammar, S. E.

    1996-05-01

    Radioactivity measurements and U and Th content determinations were carried out on 3 small granitic plutons, Gabal Abu Aqarib, Gabal El-Himeiyer and Gabal Um Zarabit, in the Central Eastern Desert. The Abu Aqarib and Um Zarabit alkali feldspar granites are elenogated bodies intruded into the Dokhan Volcanics, whereas El-Himeiyir is intruded into an ophiolitic melange section. Compared to the average content of U and Th of world granites, El-Himeiyir alkali feldspar granites show normal content of both U and Th. On the other hand, Abu Aqarib alkali feldspar granite shows some enrichments in both U and Th, whereas Um Zarabit granite shows enrichments in U contents only. The two discovered anomalous radioactive sites show 154 ppm U, and 256 ppm Th contents for Gabal Abu Aqarib site, and 24 ppm U, and 107 ppm Th contents for El-Himeiyir one. The two sites are associated with NE-trending shear zones and exhibit hydrothermal alteration features such a hematitization and silicification. The high radioactivity is ascribed to unusual accumulations of zircon and/or apatite; however, some of the enriched U may be of epigenetic origin.

  13. Mesozoic evolution of northeast African shelf margin, Libya and Egypt

    SciTech Connect

    Aadland, R.K.; Schamel, S.

    1989-03-01

    The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. The 250 km-wide and highly differentiated Mesozoic passive margin in the Western Desert region of Egypt is developed above a broad northwest-trending Late Carboniferous basement arch. In northeastern Libya, in contrast, the passive margin is restricted to just the northernmost Cyrenaica platform, where subsidence was extremely rapid in the Jurassic and Early Cretaceous. The boundary between the Western Desert basin and the Cyrenaica platform is controlled by the western flank of the basement arch. In the middle Cretaceous (100-90 Ma), subsidence accelerated over large areas of the Western desert, further enhancing a pattern of east-west-trending subbasins. This phase of rapid subsidence was abruptly ended about 80 Ma by the onset of structural inversion that uplifted the northern Cyrenaica shelf margin and further differentiated the Western Desert subbasin along a northeasterly trend.

  14. Early Cretaceous counterclockwise rotation of Northeast Africa within the equatorial zone: Paleomagnetic study on Mansouri ring complex, Southeastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Lotfy, Hamza I.

    2015-06-01

    The Mansouri ring complex (132 Ma) is, paleomagnetically, studied to shed light on the paleo-tectonic position of Northeast Africa during the Early Cretaceous. Progressive thermal demagnetization of all samples verified a general bi-vectorial decay of the natural remanence. After the removal of the present-day field overprint, the decaying anchored component was either: A dual-polarity, shallow NW-SE directed component residing in magnetite (400-585 °C) of shiny fresh samples, or, A normal-polarity, medium-inclination, north-oriented component stored in haematite of few reddish ferruginous sites. This component was considered as chemical remagnetization carried by secondary haematite. Due to its steady stability, overwhelming existence in most sites, positive reversal test and its residence in fresh-samples' magnetite, the first dual-polarity, shallow NW-SE component, was considered as the characteristic remanent magnetization [ChRM] representing the paleomagnetic field during cooling of the Mansouri ring complex. The mean paleomagnetic pole of the isolated ChRM was at 47°N/259°E, Dp/Dm = 3.4°/6.6°. This Hauterivian pole from Egypt shows reasonable consistency with its coeval poles rotated from the main tectonic units to Northeast Africa. It reveals that in Early Cretaceous: Northeast Africa was equatorial, lying just south the Equator. Cairo, which is now at 30°N, was at -1.5° paleo-latitude. The Azimuth of the African Plate was NE-SW, about 30° clockwise with respect to the present-day N-S trend. Comparing this Hauterivian pole to that of the Wadi Natash basalts [107 ± 4 Ma], which was at [55°N/250°E] during the Albian, the African Plate seems to have rotated counter-clockwise about 10° with Northeast Africa moving northwards [Cairo was moving from 1.5°S to 1.5°N] within the equatorial zone, during the Early Cretaceous.

  15. The VLF EM Method Used for Verification of Fracture/ Shear Zone Aquifers in the Hyper-arid Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Sauck, W. A.; Sultan, M.; Wagdy, A.; Roouf, O. A.

    2007-05-01

    An integrated program using Landsat remote sensing and ground follow-up with the Very Low Frequency (VLF) geophysical method was applied to the basement rocks of the Red Sea Hills (Eastern Desert) to locate fracture and shear-system aquifers. This part of the Nubian Shield was formed by accretion of a complex of ensimatic and ensialic island arcs and interleaving oceanic basins that were later accreted against the old African continent. Hence, melange and ophiolite sequences are common. This basement complex was intensely fractured (630- 530 Mybp) by the Najd transcurrent shear system (NSS) along a NW-SE trend that is up to 350 km wide, and finally the ocean-arc complex was intruded (~550 Mybp) by anorogenic K-granites. A false-color composite image was created, from Landsat thematic mapper band ratio images that are sensitive to the Fe-bearing aluminosilicate, hydroxyl, and opaque phase content of rocks. On these images mafic rocks (e.g., gabbro and mafic volcanics) rich in Fe-bearing aluminosilicates appear in shades of blue, ultramafics (e.g., serpentinites) rich in hydroxyl-bearing phases and opaque phases appear in shades of red, and granitoid rock units poor in the above phases show as green areas. Using this base map (effectively a pseudo geologic map) and a co-registered DEM, locations of potential shallow water occurrence were plotted based on the following criteria: 1) intersection of the NSS system with transverse faults defining wadis, 2) intersection of two or more fault zones, 3) within highly deformed melange units, especially their internal lithologic contacts and their crossings of wadis, 4) relatively unfractured younger dikes and their intersections with wadis. The VLF instrument was first used to make profiles at a number of existing water wells located at the structural intersections described above, to verify that sub-vertical sheet-like electrical conductors (water-filled fissures) could be successfully located with this instrument. Then

  16. Occurrence of hexavalent chromium in ground water in the western Mojave Desert, California

    USGS Publications Warehouse

    Ball, J.W.; Izbicki, J.A.

    2004-01-01

    About 200 samples from selected public supply, domestic, and observation wells completed in alluvial aquifers underlying the western Mojave Desert were analyzed for total dissolved Cr and Cr(VI). Because Cr(VI) is difficult to preserve, samples were analyzed by 3 methods. Chromium(VI) was determined in the field using both a direct colorimetric method and EPA method 218.6, and samples were speciated in the field for later analysis in the laboratory using a cation-exchange method developed for the study described in this paper. Comparison of the direct colorimetric method and EPA method 218.6 with the new cation-exchange method yielded r2 values of 0.9991 and 0.9992, respectively. Total dissolved Cr concentrations ranged from less than the 0.1 ??g/l detection limit to 60 ??g/l, and almost all the Cr present was Cr(VI). Near recharge areas along the mountain front pH values were near neutral, dissolved O2 concentrations were near saturation, and Cr(VI) concentrations were less than the 0.1 ??g/l detection limit. Chromium(VI) concentrations and pH values increased downgradient as long as dissolved O 2 was present. However, low Cr(VI) concentrations were associated with low dissolved O2 concentrations near ground-water discharge areas along dry lakes. Chromium(VI) concentrations as high as 60 ??g/l occurred in ground water from the Sheep Creek fan alluvial deposits weathered from mafic rock derived from the San Gabriel Mountains, and Cr(VI) concentrations as high as about 36 ??g/l were present in ground water from alluvial deposits weathered from less mafic granitic, metamorphic, and volcanic rocks. Chromium(III) was the predominant form of Cr only in areas where dissolved O2 concentrations were less than 1 mg/l and was detected at a median concentration of 0.1 ??g/l, owing to its low solubility in water of near-neutral pH. Depending on local hydrogeologic conditions and the distribution of dissolved O2, Cr(VI) concentrations may vary considerably with depth. Samples

  17. Chromium, chromium isotopes and selected trace elements, western Mojave Desert, USA

    USGS Publications Warehouse

    Izbicki, J.A.; Ball, J.W.; Bullen, T.D.; Sutley, S.J.

    2008-01-01

    Chromium(VI) concentrations in excess of the California Maximum Contaminant Level (MCL) of 50 ??g/L occur naturally in alkaline, oxic ground-water in alluvial aquifers in the western Mojave Desert, southern California. The highest concentrations were measured in aquifers eroded from mafic rock, but Cr(VI) as high as 27 ??g/L was measured in aquifers eroded from granitic rock. Chromium(VI) concentrations did not exceed 5 ??g/L at pH < 7.5 regardless of geology. ??53Cr values in native ground-water ranged from 0.7 to 5.1??? and values were fractionated relative to the average ??53Cr composition of 0??? in the earth's crust. Positive ??53Cr values of 1.2 and 2.3??? were measured in ground-water recharge areas having low Cr concentrations, consistent with the addition of Cr(VI) that was fractionated on mineral surfaces prior to entering solution. ??53Cr values, although variable, did not consistently increase or decrease with increasing Cr concentrations as ground-water flowed down gradient through more oxic portions of the aquifer. However, increasing ??53Cr values were observed as dissolved O2 concentrations decreased, and Cr(VI) was reduced to Cr(III), and subsequently removed from solution. As a result, the highest ??53Cr values were measured in water from deep wells, and wells in discharge areas near dry lakes at the downgradient end of long flow paths through alluvial aquifers. ??53Cr values at an industrial site overlying mafic alluvium having high natural background Cr(VI) concentrations ranged from -0.1 to 3.2???. Near zero ??53Cr values at the site were the result of anthropogenic Cr. However, mixing with native ground-water and fractionation of Cr within the plume increased ??53Cr values at the site. Although ??53Cr was not necessarily diagnostic of anthropogenic Cr, it was possible to identify the extent of anthropogenic Cr at the site on the basis of the ??53Cr values in conjunction with major-ion data, and the ??18O and ??D composition of water from wells.

  18. The hydrochemical evolution of brackish groundwater in central and northern Sinai (Egypt) and in the western Negev (Israel)

    NASA Astrophysics Data System (ADS)

    Rosenthal, E.; Zilberbrand, M.; Livshitz, Y.

    2007-04-01

    SummaryCretaceous trans-boundary aquifers in the central and northern parts of Sinai (Egypt) and the Negev (Israel), are geographically and geologically both contiguous and continuous. Hydrogeological and hydrochemical studies of these aquifers, with disregard to political boundaries, are scarce. The Lower Cretaceous Kurnub Group aquifer in Sinai and the Negev hosts paleowater mostly replenished during the Pleistocene. The objectives of this study are to elucidate the relationship between regional structural elements and the salinization of groundwater in the Kurnub Group in Sinai and further downstream in the Negev. The stable plateaus in southern Sinai and the fold structures in the north continuing into the Negev are separated by the W-E striking Minshara-Ramon shear zone. With the exception of higher salinities in the north, the chemical composition of Kurnub Group groundwater north and south of the shear zone is similar. Similarly, groundwater in the overlying Upper Cretaceous aquifer differs from Kurnub groundwater only within and north of the shear zone and is characterized by higher Cl concentrations, lower Mg/rCa ratios (due to high Ca in the calcareous aquifer) and by a "heavier" isotopic signature. Inverse hydrogeochemical modeling using PHREEQC indicates that the increase in salinity of Kurnub groundwater within the shear zone and in adjacent areas could be due to two different sources: First, the salinization process could be the result of mixing with sulfate-rich brackish groundwater occurring in Jurassic formations, which are in fault-controlled lateral contact with the Kurnub Group aquifer. Second, the salinity differences could be from unflushed seawater in the subsurface of the northern Sinai and western Negev, i.e. possible remnants of the post-Messinian (Lower Pliocene) transgression, which penetrated into northern Sinai, the western Negev and the Coastal Plain of Israel both through erosional channels, which were incised during the Neogene, and

  19. Phylogeographic structure and historical demography of the western diamondback rattlesnake (Crotalus atrox): A perspective on North American desert biogeography.

    PubMed

    Castoe, Todd A; Spencer, Carol L; Parkinson, Christopher L

    2007-01-01

    The western diamondback rattlesnake (Crotalus atrox) is a prominent member of North American desert and semi-arid ecosystems, and its importance extends from its impact on the region's ecology and imagery, to its medical relevance as a large deadly venomous snake. We used mtDNA sequences to identify population genetic structure and historical demographic patterns across the range of this species, and relate these to broader patterns of historical biogeography of desert and semi-arid regions of the southwestern USA and adjacent Mexico. We inferred a Late Pliocene divergence between peninsular and continental lineages of Crotalus, followed by an Early Mid Pleistocene divergence across the continental divide within C. atrox. Within desert regions (Sonoran and Chihuahuan Deserts, Southern Plains, and Tamaulipan Plain) we observed population structure indicating isolation of populations in multiple Pleistocene refugia on either side of the continental divide, which we attempt to identify. Evidence of post-glacial population growth and range expansion was inferred, particularly in populations east of the continental divide. We observed clear evidence of (probably recent) gene flow across the continental divide and secondary contact of haplotype lineages. This recent gene flow appears to be particularly strong in the West-to-East direction. Our results also suggest that Crotalus tortugensis (Tortuga Island rattlesnake) and a population of 'C. atrox' inhabiting Santa Cruz Island (in the Gulf of California) previously suggested to be an unnamed species, are in fact deeply phylogenetically nested within continental lineages of C. atrox. Accordingly, we suggest C. tortugensis and 'C. atrox' from Santa Cruz Island be placed in the synonymy of C. atrox. PMID:16934495

  20. Petrogenesis of carbonated meta-ultramafic lenses from the Neoproterozoic Heiani ophiolite, South Eastern Desert, Egypt: A natural analogue to CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Gahlan, Hisham A.; Arai, Shoji; Almadani, Sattam A.

    2015-02-01

    Among a set of peculiar meta-ultramafics, carbonate-orthopyroxenites are observed for the first time in the Heiani ophiolite belt, South Eastern Desert, Egypt. They form massive lensoidal masses up to 50 m long and 20 m wide. The lenses show a marked structural concordance with their neighboring country rocks. The typical country rocks are represented by the following high-grade metamorphic rocks: kyanite-muscovite schists, amphibolites, kyanite-bearing biotite gneisses, migmatites, granite gneisses and mobilizates. The studied carbonate-orthopyroxenites consist mainly of metamorphic orthopyroxene + magnesite, among other metamorphic, relict primary and retrograde secondary minerals. According to primary chromian spinel (Cr#, 0.7-0.84) chemistry and morphology, absence of clinopyroxene and presence of primary mantle olivine (Fo89-91) as relicts in the metamorphic orthopyroxene, the Heiani carbonate-orthopyroxenites seem to have formed from a highly depleted mantle peridotite precursor. At a late collisional stage during the Pan-Africa terrane accretion and the E-W crustal shortening (ca. 650-620 Ma), high-grade (upper amphibolite facies) low-P/high-T regional metamorphism (ca. 660 Ma) accompanied by CO2-metasomatism resulted in formation of the Heiani carbonate-orthopyroxenites. Mostly the carbonate-bearing shelf sediments beneath and/or in juxtaposition with the Heiani ophiolite are considered to be the proven source of the CO2-rich fluids. Although, a mixed sedimentary-mantle C source is not unlikely. A mineral paragenetic correlation with experimental data for the system MgO-SiO2-H2O-CO2 suggests metamorphic conditions consistent with those of the high-grade country rocks; i.e. 630-650 °C, 6-7 kbar (20-23 km depth) and high-XCO2 (0.6-0.7). The CO2-bearing fluids discharging along faults gave rise to regionally widespread carbonate-bearing assemblages. Accordingly, the Heiani carbonate-orthopyroxenites are considered the by-products of natural carbon

  1. Mid-Eocene alluvial-lacustrine succession at Gebel El-Goza El-Hamra (Shabrawet area, NE Eastern Desert, Egypt): Facies analysis, sequence stratigraphy and paleoclimatic implications

    NASA Astrophysics Data System (ADS)

    Wanas, H. A.; Sallam, E.; Zobaa, M. K.; Li, X.

    2015-11-01

    This study aims to provide the depositional facies, sequence stratigraphic and paleoclimatic characteristics of the Mid-Eocene (Bartonian) continental succession exposed at Gebel El-Goza El-Hamra (Shabrawet Area, NE Eastern Desert, Egypt). The studied succession consists of siliciclastic rocks followed upward by carbonate rocks. Detailed field observation and petrographic investigation indicate accumulation in floodplain-dominated alluvial and shallow lacustrine systems. The floodplain-dominated alluvial facies (45 m thick) is composed mainly of carbonate nodules-bearing, mottled mudrock with subordinate sandstone and conglomerate beds. The conglomerate and pebbly sandstone bodies interpreted as ephemeral braided channel deposits. The massive, laminated, planner cross-bedded, fine- to medium-grained sandstone bodies interlayered within mudstone reflect sheet flood deposits. The mudrocks associated with paleosols represent distal floodplain deposits. The shallow lacustrine facies (15 m thick) is made up of an alternation of marlstone, micritic limestone, dolostone and mudrock beds with charophytes and small gastropods. Both the alluvial and lacustrine facies show evidence of macro-and micro-pedogenic features. Pollen assemblages, stable δ18O and δ13C isotopes, and paleopedogenic features reflect prevalence of arid to semi-arid climatic conditions during the Bartonian. The sequence stratigraphic framework shows an overall fining-upward depositional sequence, consisting of Low- and High-accommodation Systems Tracts (LAST, HAST), and is bounded by two sequence boundaries (SB-1, SB-2). Conglomerate and pebbly sandstone deposits (braided channel and sheet flood deposits) of the lower part of the alluvial facies reflect a LAST. Mudrock and silty claystone facies (distal floodplain deposits) of the upper part of alluvial facies and its overlying lacustrine facies correspond to a HAST. The LAST, HAST and SB were formed during different accommodation-to-sediment supply (A

  2. Utilization of airborne gamma ray spectrometric data for geological mapping, radioactive mineral exploration and environmental monitoring of southeastern Aswan city, South Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Youssef, Mohamed A. S.; Elkhodary, Shadia T.

    2013-12-01

    The present work utilizes airborne gamma ray spectrometric data in a trial to refine surface geology of igneous, metamorphic and sedimentary rocks, detect any radioactive mineralization and monitor environment at southeastern Aswan city, South Eastern Desert, Egypt. This area is mainly covered with igneous rocks (younger granites, older granites, metasediments, metavolcanics, metagabbro, Tertiary basalt and ring complex), metamorphic rocks as well as sedimentary rocks (Um Barmil Formation, Timsah Formation, Abu Aggag Formation and wadi sediments). Airborne gamma ray spectrometry can be very helpful in mapping surface geology. This provides estimates of the apparent surface concentrations of the most common naturally occurring radioactive elements, such as potassium (K), equivalent uranium (eU) and equivalent thorium (eTh). This is based on the assumption that, the absolute and relative concentrations of these radioelements vary measurably and significantly with lithology. The composite image technique is used to display simultaneously three parameters of the three radioelement concentrations and their three binary ratios on one image. The technique offers much in terms of lithological discrimination, based on colour differences and showed efficiency in defining areas, where different lithofacies occur within areas mapped as one continuous lithology. The integration between surface geological information and geophysical data led to detailing the surface geology and the contacts between different rock units. Significant locations or favourable areas for uranium exploration are defined, where the measurements exceed (X + 2S), taking X as the arithmetic mean of eU, eU/eTh and eU/K measurements and S as the standard deviation corresponding to each variables. The study area shows the presence of four relatively high uraniferous zones. These zones cannot be ignored and need further ground follow-up. In addition, the trend analysis based on the three radioelement maps and

  3. Structural controls on Neoproterozoic mineralization in the South Eastern Desert, Egypt: an integrated field, Landsat TM, and SIR-C/X SAR approach

    NASA Astrophysics Data System (ADS)

    Kusky, Timothy M.; Ramadan, Talaat M.

    2002-07-01

    The Arabian-Nubian Shield represents a complex amalgam of arcs and microcontinents assembled during Neoproterozoic closure of the Mozambique Ocean. The 750-720 Ma Allaqi suture is an arc/arc collision zone, formed when the Gerf terrane in the north overrode the circa 830-720 Ma Gabgaba terrane in the south, prior to closure of the Mozambique Ocean. Neoproterozoic rocks include ophiolitic ultramafic-mafic rocks, metasediments, intermediate metavolcanic rocks, intrusive gabbro-diorite rocks, granodiorites, biotite granites, and leucocratic granites. High-pressure/low-temperature metamorphism has been documented in rocks of the suture zone. Mineral deposits include nickel-copper-platinum and podiform chromite in ultramafic rocks, marble, gold-bearing quartz-veins in D 2 and D 3 shear zones, and radioactive mineralization associated with late leucocratic granitic rocks. Integrated field mapping and remote sensing techniques are used to distinguish and map the relationships between rock units, structures, and alteration zones associated with mineral deposits along the Allaqi suture of Egypt's SE Desert. Landsat TM images processed using a band ratioing technique show different rock types remarkably well, and are able to distinguish between alteration zones associated with ultramafic rocks (listwaenites) and those associated with leucocratic granitic rocks (greisenization, silicification and albitization). Black and white L-band SIR-C/X SAR images outline foliations, faults and folds that control mineralization at several deposits in the area, whereas color composite multiband Chh-Lhh-Lhv SIR-C/X SAR images reveal some elliptical granitic bodies that host radioactive mineralization. E-trending, tight to isoclinal, gently dipping folds, thrust faults and subvertical shear zones related to the Allaqi suture are overprinted by N-oriented structures related to the Wadi Ungate shear zone, formed during collision of east and west Gondwana during closure of the Mozambique Ocean

  4. Chemistry of serpentine "polymorphs" in the Pan-African serpentinites from the Eastern Desert of Egypt, with an emphasis on the effect of superimposed thermal metamorphism

    NASA Astrophysics Data System (ADS)

    Surour, Adel A.

    2016-08-01

    The present work deals with some Pan-African serpentinites of Neoproterozoic age from five localities in the Eastern Desert of Egypt namely, Abu Fannani, Fawakhir, Barramiya, Ras Shait and Wadi Ghadir that derivedmostly from lherzolite to harzburgite protoliths. The M-value of antigorite is anindicator of the metamorphic grade which is lowest at Fawakhir (greenschist facies) and highest at Abu Fannani (lower amphibolite facies). Antigoritization during progressive regional metamorphism at Fawakhir is limited and its M-value is much higher than 8.52 indicating crystallization temperatures of 220-250 °C whereas it is ≥300 °C in the rest. Antigorite recrystallized at T ≈ 400-450 °C in the contact metamorphic aureoles due to the emplacement of post-orogenic leucogranites at Fawakhir and Gebel Ghadir. Towards the contact with the granites, M-value of antigorite is low (6.48) compared to 8.52 in the least recrystallized antigorite due to the thermal effect. Antigorite that forms in the thermal aureoles is characterized by two types of substitution; Tschermak substitution (Al3+ and Cr3+ for Si4+ in the tetrahedral sites and Mg2+ in the octahedral sites) and non-Tschermak substitutionin the octahedral sites (2R3+ = 3R2+). Generally, both ortho- and clinochrysotiles are common with MgO contents of 41-41.13 wt% and 39.38-40.93 wt%, respectively. In addition to chlorite, high- and low-Al lizardites are present with almost constant total iron (~0.24 cations) as Fe2+(vi) and variable Mg2+. This suggests that significant R3+ in the octahedral sites are mostly occupied by Al3+ and Cr3+ and not iron. In the lizardite structure, there is Tschermak substitution of Si4+ by some trivalent cations in the tetrahedral sites. Using the TEM images, antigorite is distinguishable from chrysotile and they suggest the presence of polyhedral or polygonal serpentine (spherical or circular with alternating sectors of lizardite). Crack-seal microstructures are displayed by chrysotile and

  5. Preliminary crustal deformation model deduced from GPS and earthquakes’ data at Abu-Dabbab area, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Abdel-Monem S.; Hosny, A.; Abou-Aly, N.; Saleh, M.; Rayan, A.

    2013-06-01

    A local geodetic network consisting of eleven benchmarks has been established to study the recent crustal deformation in the Abu-Dabbab area. Seven campaigns of GPS measurements have been collected started from October 2008 and ended in March 2012. The collected data were processed using Bernese version 5.0, and the result values were adjusted to get the more accurate positions of the GPS stations. The magnitudes of horizontal displacements are variable from one epoch to another and in the range of 1-3 (±0.2) mm/yr. Due to the differences in rates of the horizontal displacement; the area is divided into two main blocks. The first one, moves to the east direction of about 3 mm/yr, while the second block, moves to the SW direction of about 6 mm/yr. According to the strain fields that were calculated for the different epochs of measurement, the main force is compression force and is taken the NW-SE to NWW-SEE direction. This force could be because of local and regional tectonic processes affecting on the study area. The maximum values of compression stress are found in the southern central and western part of study area. Estimated accumulation of this strain energy may be considered as an indicator of the possibility of earthquake occurrence. From the seismic tomography study, the 3D Vp and Vp/Vs crustal models indicate high Vp/Vs values forms an elongated anomaly, in the central part of the study area, that extends from a depth of 12 km to about 1-2 km of depth is obtained. By using this crustal model in relocations all seismicity informed that most of the seismicity strongly tend to occur in a cluster manner exactly above the southern part of the study area. Based on the conducted source mechanism study, it is noticed that shallow earthquakes are associated by a high CLVD ratio (up to 40%). Furthermore, initiation of a high level seismic activity, without a large seismic main shock is observed in the Abu-Dabbab area. The distribution of micro-earthquakes tends to

  6. Multiprocess evolution of landforms in the Kharga Region, Egypt: Applications to Mars

    NASA Technical Reports Server (NTRS)

    Breed, C. S.; Mccauley, J. F.; Grolier, M. J.

    1984-01-01

    In order to understand better the polygenetic evolution of landforms on the martian surface, field studies were conducted in and around the Kharga Depression, Egypt. The Kharga region, on the eastern edge of Egypt's Western Desert, was subject to erosion under mostly hyperarid climatic conditions, punctuated by brief pluvial episodes of lesser aridity, since early Pleistocene time. The region contains numerous landforms analogous to features on the martian surface: yardangs carved in layered surficial deposits and in bedrock, invasive dune trains, wind-modified channels and interfluves, and depressions bounded by steep scarps. Like many of the topographic depresions on Mars, the Kharga Depression was invaded by crescentic dunes. In Egypt, stratigraphic relations between dunes, yardangs, mass-wasting debris, and wind-eroded flash-flood deposits record shifts in the relative effectiveness of wind, water, and mass-wasting processes as a function of climate change.

  7. Structural controls, temperature-pressure conditions and fluid evolution of orogenic gold mineralisation at the Betam mine, south Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem A.

    2008-01-01

    The Betam gold deposit, located in the southern Eastern Desert of Egypt, is related to a series of milky quartz veins along a NNW-trending shear zone, cutting through pelitic metasedimentary rocks and small masses of pink granite. This shear zone, along with a system of discrete shear and fault zones, was developed late in the deformation history of the area. Although slightly sheared and boudinaged within the shear zone, the auriferous quartz veins are characterised by irregular walls with a steeply plunging ridge-in-groove lineation. Shear geometry of rootless intra-folial folds and asymmetrical strain shadows around the quartz lenses suggests that vein emplacement took place under a brittle-ductile shear regime, clearly post-dating the amphibolite-facies regional metamorphism. Hydrothermal alteration is pervasive in the wallrock metapelites and granite including sericitisation, silicification, sulphidisation and minor carbonatisation. Ore mineralogy includes pyrite, arsenopyrite and subordinate galena, chalcopyrite, pyrrhotite and gold. Gold occurs in the quartz veins and adjacent wallrocks as inclusions in pyrite and arsenopyrite, blebs and globules associated with galena, fracture fillings in deformed arsenopyrite or as thin, wire-like rims within or around rhythmic goethite. Presence of refractory gold in arsenopyrite and pyrite is inferred from microprobe analyses. Clustered and intra-granular trail-bound aqueous-carbonic (LCO2 + Laq ± VCO2) inclusions are common in cores of the less deformed quartz crystals, whereas carbonic (LCO2 ± VCO2) and aqueous H2O-NaCl (L + V) inclusions occur along inter-granular and trans-granular trails. Clathrate melting temperatures indicate low salinities of the fluid (3-8 wt.% NaCl eq.). Homogenisation temperatures of the aqueous-carbonic inclusions range between 297 and 323°C, slightly higher than those of the intra-granular and inter-granular aqueous inclusions (263-304°C), which are likely formed during grain boundary

  8. Zonation of primary haloes of Atud auriferous quartz vein deposit, Central Eastern Desert of Egypt: A potential exploration model targeting for hidden mesothermal gold deposits

    NASA Astrophysics Data System (ADS)

    Harraz, Hassan Z.; Hamdy, Mohamed M.

    2015-01-01

    The Atud gold mine located in the Neoproterozoic diorite and metagabbro of the Central Eastern Desert of Egypt has been initially excavated during Pharaonic times. Between 1953 and 1969, the Egyptian Geological Survey and Mining Authority performed underground prospection in the auriferous quartz vein and metasomatic alteration zones in the main Atud area, estimating a principal gold lode of 19,000 tones (16.28 g/ton), and 1600 tons of damp (1.24 g/ton). Yet the potentiality of the deposit has not been exhausted. However, for exploration of hidden ore, quantitative characterization using trace elements zoning of mineralization haloes with 280 samples from surface and three underground mining levels is applied. This was through multivariate statistical analysis (Factor analysis) of 11 selected trace elements. Axial (vertical) extents of primary haloes above and beneath gently dipping orebody are also visualized to interpret the level of erosion, determine the direction of mineralizing solutions as well as to examine whether the hidden orebody is promising at the Atud mine. Axial zones of primary dispersion aureoles of trace elements are: Ag, As, S and U around the auriferous quartz veins; Cu, and Pb in the surface horizons; and Zn, Ni, Co, and U along the lower margin of mineralization zone. Gold contents in bedrock and quartz vein samples from level-42M are the highest (5.7 and 40.3 ppm, respectively). In the transverse (lateral) direction, the maximum relative accumulation of Au and Zn occurs at the Northern Shaft; Pb, Cu, As, and U at the Main Shaft; and Ag, S, Co, and Ni at the Southern Shaft. The estimated axial zonation sequence of indicator elements using the variability index is Pb → Cu → Ag → Au → As → S → Ni → Co → U → Zn. According to this zonation, an index such as (Pb × Cu)D/(U × Zn)D can be a significant for predicting the Au potentiality at a particular depth. In addition, the Pb/U zonality index is an appropriate indicator for the

  9. Westward prograding metamorphism in mantle peridotites from the Eastern Desert of Egypt: clues to the subduction polarity of the Arabian Nubian Shield intra-oceanic arc ophiolite

    NASA Astrophysics Data System (ADS)

    Salam Abu El-Ela, Abdel; Hamdy, Mohamed; Abu-Alam, Tamer; Hassan, Adel; Gamal El Dien, Hamed

    2013-04-01

    Neoproterozoic arc mantle beneath the Arabian Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt exhumed due to intra-oceanic upthrusting are represented mainly by exposed ophiolitic peridotites serpentinized to different degree. Metamorphism is related to the Pan-African collision and the subduction of oceanic lithosphere. However, polarity of the Pan-African intra-oceanic subduction is still questionable. We here trace the variation of the degree of serpentinization and regional metamorphism of six serpentinite masses, widely distributed in the ED (from the east to the west: W (Wadi). Alam, W. Igla, W. Mubarak, G. El-Maiyit, W. Um El Saneyat and W. Atalla). This is based on their mineralogy, textures and mineral chemistry. The studied rocks have harzburgite composition and they all formed in oceanic mantle wedge in the fore-arc setting, except those from W. Atalla that formed in MOR-arc transition setting. Much difference in the degree of serpentinization is obvious among these rocks. They are mainly partly serpentinized containing primary olivine and orthopyroxene at W. Alam and W. Igla, while they are completely serpentinized in the other localities. With the increased degree of metamorphism, textures were transformed from the pseudomorphic to the non-pseudomorphic. The most common retrograde assemblage is composed of lizardite ± chrysotile± brucite± magnetite. The serpentine prograde textures can be viewed as a continuum from retrograde lizardite pseudomorphic textures, to very fine-grained transitional texture of lizardite and chrysotile, to chrysotile-antigorite interlocking texture and finally to antigorite interpenetrating texture. These textures appear to represent successive stages in a recrystallization event. In late subduction-related metamorphism and early collisional emplacement stage, mylonitic-antigorite serpentinites formed and antigorite became the major phase in G. El-Maiyit, Um El-Saneyat and W. Atalla. The polygonal units of the

  10. Subduction-related cryptic metasomatism in fore-arc to nascent fore-arc Neoproterozoic mantle peridotites beneath the Eastern Desert of Egypt: mineral chemical and geochemical evidences

    NASA Astrophysics Data System (ADS)

    Hamdy, Mohamed; Salam Abu El-Ela, Abdel; Hassan, Adel; Kill, Youngwoo; Gamal El Dien, Hamed

    2013-04-01

    Mantle spinel peridotites beneath the Arabian Nubian Shield (ANS) in the Eastern Desert (ED) of Egypt were formed in arc stage in different tectonic setting. Thus they might subject to exchange with the crustal material derived from recycling subducting oceanic lithosphere. This caused metasomatism enriching the rocks in incompatible elements and forming non-residual minerals. Herein, we present mineral chemical and geochemical data of four ophiolitic mantle slice serpentinized peridotites (W. Mubarak, G. El-Maiyit, W. Um El Saneyat and W. Atalla) widely distributed in the ED. These rocks are highly serpentinized, except some samples from W. Mubarak and Um El-Saneyat, which contain primary olivine (Fo# = 90-92 mol %) and orthopyroxene (En# = 86-92 mol %) relics. They have harzburgite composition. Based on the Cr# and Mg# of the unaltered spinel cores, all rocks formed in oceanic mantle wedge in the fore-arc setting, except those from W. Atalla formed in nascent fore-arc. This implies that the polarity of the subduction during the arc stage was from the west to the east. These rocks are restites formed after partial melting between 16.58 in W. Atalla to 24 % in G-El Maiyit. Melt extraction occurred under oxidizing conditions in peridotites from W. Mubarak and W. Atalla and under reducing conditions in peridotites from G. El-Maiyit and Um El-Saneyat. Cryptic metasomatism in the studied mantle slice peridotites is evident. This includes enrichment in incompatible elements in minerals and whole rocks if compared with the primitive mantle (PM) composition and the trend of the depletion in melt. In opx the Mg# doesn't correlate with TiO2, CaO, MnO, NiO and Cr2O3concentrations. In addition, in serpentinites from W. Mubarak and W. Atalla, the TiO2spinel is positively correlated with the TiO2 whole-rock, proposing enrichment by the infiltration of Ti-rich melts, while in G. El- Maiyit and Um El-Saneyat serpentinites they are negatively correlated pointing to the reaction

  11. Multi-element association analysis of stream sediment geochemistry data for predicting gold deposits in Barramiya gold mine, Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Harraz, Hassan Z.; Hamdy, Mohamed M.; El-Mamoney, Mohamed H.

    2012-06-01

    The use of traditional statistical methods can provide suitable indicators of geochemical element dispersion, and aids in targeting potential areas for mineral exploration. Analyzes of stream sediments from an ophiolite suite of ophiolitic mélange matrix and metasediments belt are used for regional geochemical prospecting of gold in the Barramiya mining district, Eastern Desert, Egypt. The principal rocks exposed in the study area are Late-Proterozoic volcano-sedimentary sequences intruded by serpentinite, small bodies of Older and Younger Granitoids, all injected by dykes of various compositions. Gold production derived mainly from shear zone with Au-bearing quartz veins hosted by ultramafic schists and serpentinites at fault intersections or along the basal décollement of the major thrusts, especially where granitoid massifs and stocks are common. Orebodies are mainly sulfide-bearing quartz and quartz-carbonate lodes associated with graphite-schist, listvenite and marble exposures, showing signs of structural control expressed in preferable orientation and consistent meso- and microfabrics. The area has two known gold deposits where several chromite mines are present. Auriferous veins are confined along E and ENE fracture systems and zones in a passive tectonic contact between the serpentinites and the metasediments. Results of 425 stream sediment samples from an area of ˜73 km2 analyzed for 13 trace elements are presented using simple statistical and R-mode factor methods. The overall sample density achieved by the survey is ˜6 samples/km2. Significant variations in background metal contents are recorded near the known mineralized sites. Preliminary visual interpretation of individual spatial distribution patterns of Ag, As, Au, Cu, Mo, Pb, and W show clear-cut relationships with known gold mineralization in the study area. Geochemical patterns of these elements delineate drainage basins with anomalous concentration of elements genetically related to gold

  12. Implications of high altitude desert dust transport from Western Sahara to Nile Delta during biomass burning season.

    PubMed

    Prasad, Anup K; El-Askary, Hesham; Kafatos, Menas

    2010-11-01

    The air over major cities and rural regions of the Nile Delta is highly polluted during autumn which is the biomass burning season, locally known as black cloud. Previous studies have attributed the increased pollution levels during the black cloud season to the biomass or open burning of agricultural waste, vehicular, industrial emissions, and secondary aerosols. However, new multi-sensor observations (column and vertical profiles) from satellites, dust transport models and associated meteorology present a different picture of the autumn pollution. Here we show, for the first time, the evidence of long range transport of dust at high altitude (2.5-6 km) from Western Sahara and its deposition over the Nile Delta region unlike current Models. The desert dust is found to be a major contributor to the local air quality which was previously considered to be due to pollution from biomass burning enhanced by the dominant northerly winds coming from Europe. PMID:20797813

  13. Calcareous nannofossil and planktonic foraminifera biostratigraphy through the Middle to Late Eocene transition of Fayum area, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Marzouk, Akmal Mohamed; El Shishtawy, Ahmed Moustafa; Kasem, Atef Masoud

    2014-12-01

    The Eocene sequence exposed at Gebel Naalun (Fayum-Nile divide), Guta section-I (West of Birket Qarun near Guta Village) and Guta section-II (Northwest of Birket Qarun near Guta Village) is differentiated, from base to top, into two formations; Gehannam Formation (Middle-Late Eocene) and Birket Qarun Formation (Late Eocene), respectively. Two calcareous nannofossil zones were recognized from the Eocene succession at Gebel Naalun; Discoaster saipanensis (NP17) and Chiasmolithus oamaruensis (NP18) zones as well as one planktonic foraminiferal zone; Truncorotaloides (Acaranina) rohri (P14) zone. However, at Guta section-I, two nannofossil zones were defined; Discoaster saipanensis (NP17) and Chiasmolithus oamaruensis (NP18) zones; the preservation of planktonic foraminiferal assemblage is too poor to enable us to recognize marker species as a result of many diagenetic processes. At Guta section-II, two nannofossil zones; Chiasmolitus oamaruensis (NP18) and Isthmolithus recurvus (NP19) and two planktonic foraminiferal zones; T. pseudoampliapertura zone and G. semiinvoluta zone are recorded. Several authors found that the lowest occurrence of Chiasmolithus oamaruensis is a poor criterion for defining the base of NP18 Zone, which is confirmed here. The same criticism has been applied to the lowest occurrence of Isthmolithus recurvus which defines the NP18/NP19 zonal boundary. It is generally agreed that NP19 Zone falls in the Priabonian (Late Eocene). As a result of the occurrence of the nannofossil marker species; Isthmolithus recurvus only in side views below and above the first appearance of Chiasmolithus oamaruensis at both Naalun and Guta section-I, this species is not reliable to define the NP18/NP19 zonal boundary. At Guta section-II, the Middle/Upper Eocene boundary can be delineated by the first appearance of Globigerinatheka semiinvoluta above the first occurrence of Isthmolithus recurvus in both plane and side views.

  14. Mirages in the Desert: Theorizing Western Muslim Identity across 60 Years

    ERIC Educational Resources Information Center

    El-Sherif, Lucy

    2016-01-01

    Theorizations on Western Muslim identity that are multi-layered and grounded in actual Western Muslim experiences are hard to find. Two exceptions to this are "The Road to Mecca" by Muhammad Asad (1954/2005), and "Islam is a Foreign Country" by Zareena Grewal (2014), rich texts that span across six decades. Asad's classic…

  15. Seasonal metabolic acclimatization in the herbivorous desert lizard Uromastyx philbyi (Reptilia: Agamidea) from western Saudi Arabia.

    PubMed

    Zari, Talal A

    2016-08-01

    Many ectotherms adjust their metabolic rate seasonally in association with variations in environmental temperatures. The range and direction of these seasonal changes in reptilian metabolic rates are thought to be linked to the seasonality of activity and energy requirements. The present study was conducted to measure the standard metabolic rate (SMR) of seasonally-acclimatized Uromastyx philbyi with different body masses at 20, 25, 30, 35 and 40°C using open-flow respirometry during the four seasons. SMR was mass-dependent. The mean exponent of mass, "b", in the metabolism-body mass relation was 0.76 (variance=0.0007). Likewise, SMR increased as temperature increased with low Q10 values at high temperatures and high Q10 values at low temperatures. The lowest and highest Q10 values were achieved for temperature ranges of 30-35°C for summer-acclimatized dhabbs (Q10=1.6) and 20-25°C for winter-acclimatized dhabbs (Q10=3.9). Seasonal acclimatization effects were obvious at all temperatures (20-40°C). Winter-acclimatized dhabbs had the lowest metabolic rates at all temperatures. The seasonal acclimatization patterns displayed by U. philbyi may represent a valuable adaptation for herbivorous desert lizards that inhabit subtropical deserts to facilitate activity during their active seasons and to conserve energy during inactivity at low temperatures. PMID:27503731

  16. Optical characteristics of biomass burning and desert dust over the Western Mediterranean during summer: a case study

    NASA Astrophysics Data System (ADS)

    Basart, Sara; Sicart, Michaël; María Baldasano, José; Lane, Diego; Comerón, Adolfo

    2013-04-01

    The present contribution reports on the aerosol vertical distributions in Barcelona (Spain) which were obtained when very high aerosol concentrations were observed on summer 2012. An EARLINET lidar system and AERONET sunphotometer located in Barcelona performed intensive measurements in the framework of the ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) project. The data that were collected allow the characterization of the optical properties of the aerosols in this region, benefiting from the synergy of various remote sensing instruments. Due to its location in the Mediterranean basin, Barcelona metropolitan area is influenced by two major aerosol source regions: Europe and the Western Mediterranean Basin, as a major source of anthropogenic pollutants, and North Africa, as a principal source of natural dust. As a result, the composition of atmospheric aerosols in Barcelona station is a mixing of aerosols. During the period between 1 - 2 July, AOD reached high values (~ 0.5). In addition to anthropogenic local contributions, other aerosols long-range transported were also detected. Between 1 - 3 July, strong forest fires occurred in Alicante where advected to Barcelona area. On the other hand, between 28th June and 1st July, the northeastern Iberian Peninsula was affected by the intrusion of Saharan dust. The presence of Saharan dust was successfully forecasted by the BSC-DREAM8b dust regional model. MODIS and AERONET data, as well as air-mass backward trajectories confirmed the existence of biomass burning and desert dust in the case examined. Desert dust was detected between 2 and 4 km (above sea level, a.s.l) with maximum dust concentrations at ~ 4 km a.s.l on 1st June. On the other hand, favourable meteorological conditions made possible that biomass burning from Alicante was southern advected to Barcelona during the study period.

  17. Paleomagnetism of middle Miocene volcanic rocks in the Mojave-Sonora desert region of western Arizona and southeastern California

    SciTech Connect

    Calderone, G.J. ); Butler, R.F.; Acton, G.D. )

    1990-01-10

    Paleomagnetic directions have been obtained from 190 early to middle Miocene (12-20 Ma) mafic volcanic flows in 16 mountain ranges in the Mojave-Sonora desert region of western Arizona and southeastern California. These flows generally postdate early Miocene tectonic deformation accommodated by low-angle normal faults but predate high-angle normal faulting in the region. After detailed demagnetization experiments, 179 flows yielded characteristic directions interpreted as original thermal remanent magnetizations (TRM). Because of the episodic nature of basaltic volcanism in this region, the 179 flows yielded only 65 time-distinct virtual geomagnetic poles (VGPs). The paleomagnetic pole calculated from the 65 cooling unit VGPs is located at 85.5{degree}N, 108.9{degree}E within a 4.4{degree} circle of 95% confidence. This pole is statistically indistinguishable (at 95% confidence) from reference poles calculated from rocks of similar age in stable North America and from a paleomagnetic pole calculated from rocks of similar age in Baja California. The coincidence of paleomagnetic poles from the Mojave-Sonora desert region with reference poles from the stable continental interior indicates that (1) significant vertical axis net tectonic rotations have not accompanied post-middle Miocene high-angle normal faulting in this region; (2) there has been no detectable post-middle Miocene latitudinal transport of the region; and (3) long-term nondipole components of the middle Miocene geomagnetic field probably were no larger than those of the recent (0-5 Ma) geomagnetic field. In contrast, paleomagnetic data indicate vertical axis rotations of similar age rocks in the Transverse Ranges, the Eastern Transverse Ranges, and the Mojave Block.

  18. Fugitive dust mitigation for PM{sub 10} attainment in the western Mojave Desert: Recommendations on revegetation

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L. |; Roberts, E.

    1997-12-31

    Methods to suppress fugitive dust and associated violations of federal PM{sub 10} standards in the western Mojave Desert, following removal of native vegetation by tillage or overgrazing, have been under investigation by a multi-agency task force for several years. Interim recommendations are now possible for this area of high winds, low rainfall, and mostly arable soil with patchy blowing sand. There can be no guarantee of success in any revegetation program in the desert, but the greatest probability of success in this area can be attained by using the native shrub Atriplex canescens, whether direct seeded or transplanted. No additional nitrogen should be added, and excess nitrogen should be removed if possible, perhaps by a preliminary cropping of barley. This will itself stabilize the soil surface in the short term. Young plants should be protected from herbivory and the harsh elements by using plastic cones. Irrigation is helpful if available. In areas located near native populations of rabbitbrush annual plant cover should be burned but no tillage or other soil disturbance should be imposed, as this facilitates invasion of annual species, including russian thistle, and prevents establishment of rabbitbrush. In sandy areas, seeding with Indian ricegrass may be more effective than with A. canescens. For immediate, short-term, mitigation of blowing dust, furrowing alone and installation of windfences may be effective. Rainfall exhibits high annual variability in arid regions. Absence of fugitive dust emissions in rainy periods, associated with ground cover by annual vegetation, is unlikely to survive several years of low, but normal, rainfall. It is precisely during those periods when rainfall is adequate that long-term revegetation with shrubs has the best chance of success.

  19. Geothermal resources of the Western Arm of the Black Rock Desert, northwestern Nevada; Part II, Aqueous geochemistry and hydrology

    USGS Publications Warehouse

    Welch, A.H.; Preissler, A.M.

    1990-01-01

    The western arm of the Black Rock Desert, Nevada, includes several distinct hydrothermal systems, some of which exceed 150 C and may exceed 200 C at depth, determined on the basis of chemical geothermometry. The cation composition of the thermal water appears to be controlled by aluminosilicate minerals that are common in other active geothermal systems. Estimates of the equilibrium temperatures at which some mineral pairs are stable, when compared with the more commonly applied geothermometer estimates, indicate that thermodynamic data may be useful for estimating deep aquifer temperatures. Thermal water at Great Boiling and Mud Springs, which has a chloride concentration of about 2,000 mg/L and a total dissolved-solids concentration of 4 ,500 mg/L, appears to have been affected by shallow evapotranspiration in an adjacent playa prior to deep circulation. This model of recharge within the basin floor is distinctly different from models proposed for most other geothermal systems in the northern Great Basin. (USGS)

  20. Isolation and characterization of osmotolerant bacteria from thar desert of western Rajasthan (India).

    PubMed

    Sharma, Ramavtar; Manda, Rajni; Gupta, Shikha; Kumar, Sushil; Kumar, Vinod

    2013-12-01

    The Thar Desert harsher environment harbors a limited diversity of life forms due to extreme conditions like low moisture of sandy soils and high soil temperature. In the present study, osmotolerant bacteria from the Thar soils were isolated and characterized. Bacteria were isolated from 20 soil samples (100 g), collected from sand dunes, suspended in water and absolute alcohol. A total of 11 biochemical and morphological tests were carried out for generic identification of bacteria. Osmotic tolerance capacity of isolates was examined on glycerol, NaCI and alcohol; and sequencing of 16S rRNA gene was also performed for bacterial identification. 16S to 23S rRNA internal transcribed spacer analysis (RISA) was done for phylogenetic analysis of isolates. The soil suspended in water contained 2.5 x 10(6) bacteria/g of soil while alcohol suspended soil had 4.4 x 10(4) bacteria/g. The 24 bacterial isolates were found tolerant to 26% glycerol, 14% NaCI and 10% of alcohol, and 22 out of 24 isolates were found Gram positive. The results showed that 45.83% and 41.67% bacteria belong to Bacillus spp. and Corynebacterium spp., respectively, while Acinetobacter spp., Aeromonas spp. and Staphylococcus spp. were in equal proportion (4.16% each). Six isolates were selected for 16S rRNA gene sequencing and five were found 95% similar with Bacillus licheniformis whereas one isolate was identified as B. subtilis. All the isolates showed good growth up to 50 degrees C with gradual reduction on subsequent increment of temperature. Out of 24 isolates, six could survive at 65 degrees C while one isolate could grow at 63 degrees C. Growth kinetic studies revealed that the reduction in generation time in solute(s) and temperature stress was more as compared to generation time in plain medium. This study suggests that virgin sand dunes may be a rich source of bacteria, tolerant to osmotrophic solutes, and can be examined for plant growth promotion activity in agriculture. Moreover, study

  1. Atmospheric aerosols size distribution properties in winter and pre-monsoon over western Indian Thar Desert location

    NASA Astrophysics Data System (ADS)

    Panwar, Chhagan; Vyas, B. M.

    2016-05-01

    The first ever experimental results over Indian Thar Desert region concerning to height integrated aerosols size distribution function in particles size ranging between 0.09 to 2 µm such as, aerosols columnar size distribution (CSD), effective radius (Reff), integrated content of total aerosols (Nt), columnar content of accumulation and coarse size aerosols particles concentration (Na) (size < 0.5 µm) and (Nc) (size between 0.5 to 2 µm) have been described specifically during winter (a stable weather condition and intense anthropogenic pollution activity period) and pre-monsoon (intense dust storms of natural mineral aerosols as well as unstable atmospheric weather condition period) at Jaisalmer (26.90°N, 69.90°E, 220 m above surface level (asl)) located in central Thar desert vicinity of western Indian site. The CSD and various derived other aerosols size parameters are retrieved from their average spectral characteristics of Aerosol Optical Thickness (AOT) from UV to Infrared wavelength spectrum measured from Multi-Wavelength solar Radiometer (MWR). The natures of CSD are, in general, bio-modal character, instead of uniformly distributed character and power law distributions. The observed primary peaks in CSD plots are seen around about 1013 m2 μm-1 at radius range 0.09-0.20 µm during both the seasons. But, in winter months, secondary peaks of relatively lower CSD values of 1010 to 1011 m2/μm-1 occur within a lower radius size range 0.4 to 0.6 µm. In contrast to this, while in dust dominated and hot season, the dominated secondary maxima of the higher CSD of about 1012 m2μm-3 is found of bigger aerosols size particles in a rage of 0.6 to 1.0 µm which is clearly demonstrating the characteristics of higher aerosols laden of bigger size aerosols in summer months relative to their prevailed lower aerosols loading of smaller size aerosols particles (0.4 to 0.6 µm) in cold months. Several other interesting features of changing nature of monthly spectral AOT

  2. Magnetostratigraphy of the Western Borrego Badlands, Anza-Borrego Desert, California - Implications for Tectonics and Litho- and Biostratigraphic Control

    NASA Astrophysics Data System (ADS)

    Remeika, P.; Liddicoat, J. C.; Beske-Diehl, S.

    2008-12-01

    Over 200 meters of non-marine fluvial-floodplain sediments and volcanic ashes are exposed in the Borrego Badlands as part of the northwest margin of the Borrego-San Filipe Basin in the Anza-Borrego Desert, Califorinia. Our stratigraphic and paleomagnetic investigations provide data regarding the age and character of the sediments and tectonics of the region. The intrabasin sediments in Mammoth Cove and Rainbow Wash are especially favorable for paleomagnetic and biostratigraphic analysis due to their fine-grained lithology, abundant vertebrate fossils (Borrego Local Fauna) of Irvingtonian Land Mammal Age, and a continuous syndepositional record of alluvial fan, lacustrine, and playa-margin deposition in response to wrench tectonics associated with the seismogenic San Jacinto Fault Zone. The mean paleomagnetic directions following thermal demagnetization to 600°C are Incl. = 44.9°, Decl. = 11.6°, alpha-95 = 10.4°, k = 13.5, n = 16 for samples from the Brunhes Normal Chron, and Incl. = -46.5°, Decl. = 201.3°, alpha-95 = 8.6°, k = 18.1, n = 17 for samples from the Matuyama Reverse Chron. Those directions are reasonable when compared to the directions reported for older deposits in the Vallecito-Fish Creek Basin in the eastern part of the Anza-Borrego Desert (Johnson et al., 1983); those directions are Incl. = 41.6°, Decl. = 30.6°, alpha-95 = 7.4°, k = 13.1 for samples that record normal polarity, and Incl. = -35.1°, Decl. = 219.4°, alpha-95 = 7.4°, k = 9.6 for samples that record reverse polarity. By contrast, sediments deposited during the lower Matuyama Reverse Chron and upper Gauss Normal Chron where we sampled in Rainbow Wash are rotated clockwise by a greater amount - almost 90°. That rotation patterns the nearly 90° of clockwise rotation of volcanic rocks in the Western Transverse Ranges (Luyendyk, 1991) and non-marine Sespe Fm. (Liddicoat, 1990; 2001) north of the Los Angeles Basin that began about 15 million years ago (Luyendyk, 1991).

  3. U-Pb ID-TIMS dating of igneous and metaigneous rocks from the El-Sibai area: time constraints on the tectonic evolution of the Central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Augland, Lars Eivind; Andresen, Arild; Boghdady, Gamal Yehia

    2012-01-01

    This paper presents new ID-TIMS U-Pb zircon and titanite ages from the El-Sibai gneiss complex in the Eastern Desert of Egypt. The zircon data support previous studies, indicating that the protoliths of the gneissic (oldest) units in the area were emplaced during the East African orogeny, and do not represent an older pre-Neoproterozoic, reworked cratonic basement. The crystallization ages of three compositionally distinct orthogneiss protoliths are c. 685, 682 and 679 Ma, respectively. A U-Pb titanite age from one orthogneiss overlaps with the protolith age, indicating that the gneisses did not undergo post-magmatic high-temperature metamorphism. The gneissic textures of the rocks are therefore interpreted to reflect syn-emplacement deformation. This, and evidence for static amphibolite facies metamorphism in country-rock metavolcanics, lead us to conclude that the gneisses of El-Sibai do not represent an exhumed middle crustal gneiss dome, but are part of the island arc affined allochthon into which they were emplaced synchronously with NW-ward nappe translation. We also report ages from rocks cross-cutting the gneisses and the surrounding island arc affined assemblages that yield the hitherto youngest robust pre-Cretaceous intrusive ages in the Eastern Desert. The dated rocks are an anorthosite and a cross-cutting syenogranite giving ages of c. 541 and 540 Ma, respectively. We consider this late magmatic pulse to be anorogenic, most likely reflecting a separate extensional event involving asthenospheric upwelling and decompression melting of the mantle.

  4. The meaning of desert color in earth orbital photographs

    NASA Technical Reports Server (NTRS)

    El-Baz, F.

    1978-01-01

    The color of desert surfaces as seen in earth orbital photographs is indicative of soil composition. Apollo-Soyuz photographs of the Sturt and Simpson Deserts of Australia confirm that sand grains become redder as the distance from the source increases. Reddening is caused by a thin iron-oxide coating on individual sand grains and can be used, in some cases, to map relative-age zones. Photographs of the Western (Libyan) Desert of Egypt indicate three distinct and nearly parallel color zones that have been correlated in the field with: (1) arable soil composed of quartz, clay, and calcium carbonate particles; (2) relatively active sand with or without sparse vegetation; and (3) relatively inactive sand mixed with dark (desert-varnished) pebbles. The youngest sands are in the form of longitudinal dunes, which are migrating to the south-southeast along the prevailing wind direction. Some of the young dune fields are encroaching on the western boundary of the fertile Nile Valley.

  5. Evidence for population fragmentation within a subterranean aquatic habitat in the Western Australian desert

    PubMed Central

    Guzik, M T; Cooper, S J B; Humphreys, W F; Ong, S; Kawakami, T; Austin, A D

    2011-01-01

    The evolution of subterranean animals following multiple colonisation events from the surface has been well documented, but few studies have investigated the potential for species diversification within cavernicolous habitats. Isolated calcrete (carbonate) aquifers in central Western Australia have been shown to contain diverse assemblages of aquatic subterranean invertebrate species (stygofauna) and to offer a unique model system for exploring the mechanisms of speciation in subterranean ecosystems. In this paper, we investigated the hypothesis that microallopatric speciation processes (fragmentation and isolation by distance (IBD)) occur within calcretes using a comparative phylogeographic study of three stygobiontic diving beetle species, one amphipod species and a lineage of isopods. Specimens were sequenced for the mitochondrial cytochrome c oxidase 1 gene from three main sites: Quandong Well, Shady Well (SW) and Mt. Windarra (MW), spanning a 15 km region of the Laverton Downs Calcrete. Phylogenetic and haplotype network analyses revealed that each species possessed a single divergent clade of haplotypes that were present only at the southern MW site, despite the existence of other haplotypes at MW that were shared with SW. IBD between MW and SW was evident, but the common phylogeographic pattern most likely resulted from fragmentation, possibly by a salt lake adjacent to MW. These findings suggest that microallopatric speciation within calcretes may be a significant diversifying force, although the proportion of stygofauna species that may have resulted from in situ speciation in this system remains to be determined. PMID:21343944

  6. Evidence for population fragmentation within a subterranean aquatic habitat in the Western Australian desert.

    PubMed

    Guzik, M T; Cooper, S J B; Humphreys, W F; Ong, S; Kawakami, T; Austin, A D

    2011-09-01

    The evolution of subterranean animals following multiple colonisation events from the surface has been well documented, but few studies have investigated the potential for species diversification within cavernicolous habitats. Isolated calcrete (carbonate) aquifers in central Western Australia have been shown to contain diverse assemblages of aquatic subterranean invertebrate species (stygofauna) and to offer a unique model system for exploring the mechanisms of speciation in subterranean ecosystems. In this paper, we investigated the hypothesis that microallopatric speciation processes (fragmentation and isolation by distance (IBD)) occur within calcretes using a comparative phylogeographic study of three stygobiontic diving beetle species, one amphipod species and a lineage of isopods. Specimens were sequenced for the mitochondrial cytochrome c oxidase 1 gene from three main sites: Quandong Well, Shady Well (SW) and Mt. Windarra (MW), spanning a 15 km region of the Laverton Downs Calcrete. Phylogenetic and haplotype network analyses revealed that each species possessed a single divergent clade of haplotypes that were present only at the southern MW site, despite the existence of other haplotypes at MW that were shared with SW. IBD between MW and SW was evident, but the common phylogeographic pattern most likely resulted from fragmentation, possibly by a salt lake adjacent to MW. These findings suggest that microallopatric speciation within calcretes may be a significant diversifying force, although the proportion of stygofauna species that may have resulted from in situ speciation in this system remains to be determined. PMID:21343944

  7. Bioprospecting of plant growth promoting psychrotrophic Bacilli from the cold desert of north western Indian Himalayas.

    PubMed

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Saxena, Anil Kumar

    2016-02-01

    The plant growth promoting psychrotrophic Bacilli were investigated from different sites in north western Indian Himalayas. A total of 247 morphotypes were obtained from different soil and water samples and were grouped into 43 clusters based on 16S rDNA-RFLP analysis with three restriction endonucleases. Sequencing of representative isolates has revealed that these 43 Bacilli belonged to different species of 11 genera viz., Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus and Virgibacillus. With an aim to develop microbial inoculants that can perform efficiently at low temperatures, all representative isolates were screened for different plant growth promoting traits at low temperatures (5-15 degrees C). Among the strains, variations were observed for production (%) of indole-3-acetic acid (20), ammonia (19), siderophores (11), gibberellic acid (4) and hydrogen cyanide (2); solubilisation (%) of zinc (14), phosphate (13) and potassium (7); 1-aminocyclopropane-1-carboxylate deaminase activity (6%) and biocontrol activity (4%) against Rhizoctonia solani and Macrophomina phaseolina. Among all the strains, Bacillus licheniformis, Bacillus muralis, Desemzia incerta, Paenibacillus tylopili and Sporosarcina globispora were found to be potent candidates to be developed as inoculants as they exhibited multiple PGP traits at low temperature. PMID:26934782

  8. Active synchronous counterclockwise rotation and northwards translation of Africa toward Eurasia during the Late Cretaceous: A paleomagnetic study on the Alkaline volcanic field of Wadi Natash (ca. 100-86Ma), South Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Lotfy, H.

    2009-04-01

    In order to shed light on the paleo-tectonic movement of Africa during the Late Cretaceous, the two end members of the alkaline volcanic field of Wadi Natash (ca. 100-86Ma) in the South Eastern Desert of Egypt were studied paleomagnetically. The Wadi Natash volcanic field (24.5°N-34.25°E) is made up of a succession of differentiated flows grading from alkali olivine basalt [AOB] to trachyte-phonolite [Tr/Ph]. The oldest flows of the AOB (104±7 Ma) and the youngest Tr/Ph plugs and ring dykes (86Ma) as well as the interflows sandstones [ previously know as Nubian sandstone were sampled allover the field > 400km2. The isothermal remanent magnetization [IRM] study revealed that the remanence in Wadi Natash volcanics reside mainly in magnetite with some subsidiary goethite/hematite sites. On the other hand, goethite/hematite are the sole remanence carriers in the Nubian-type interflow sandstone. After the progressive stepwise thermal demagnetization of all samples, the visual isolation and subsequent calculation of the best-fit line of the characteristic remanence [ChRM] direction of each sample, followed by the calculation of the site and rock-unit means revealed that: 1- In the tilt-corrected coordinates, the mean ChRM of the oldest AOB flows [N=12 sites

  9. Present groundwater status in Egypt and the environmental impacts

    NASA Astrophysics Data System (ADS)

    Idris, Hussein; Nour, S.

    1990-11-01

    This article is an attempt to give a brief review on the status of groundwater studies in Egypt, their results, and the present plans for groundwater development that are usually based on the hydrogeological characteristics of the groundwater resources as well as on the environmental control of the discharge area. In terms of groundwater hydrology, Egypt can be divided into the following groundwater provinces: (1) the Western Desert, (2) the Eastern Desert, (3) the Nile Valley including the delta, (4) the Sinai Peninsula, (5) the Northern Coastal Zone, and (6) Wadi El-Natrun. The studies of volume and nature of groundwater and the environmental impact studies that were carried out in each of these provinces differed according to the importance given to development of projects in areas of interest and to the availability of funds. Recent studies and the surveys conducted for groundwater hydrological research by local and international organizations are described separately for each province. Special reference is made to groundwater hydro-geological setting, groundwater resources evaluation, and present and future utilization. The New Valley is the largest Egyptian irrigated agricultural development project that is solely dependent on groundwater resources. An outline showing its nature, objective, and size is included as an example of groundwater development.

  10. Combining molecular-marker and chemical analysis of Capparis decidua (Capparaceae) in the Thar Desert of Western Rajasthan (india).

    PubMed

    Kumar, Sushil; Sharma, Ramavtar; Kumar, Vinod; Vyas, Govind K; Rathore, Abhishek

    2013-03-01

    The Thar Desert, a very inhospitable place, accommodates only plant species that survive acute drought, unpredictable precipitation, and those can grow in the limited moisture of sandy soils. Capparis decidua is among one of the few plants able to grow well under these conditions. This species is highly exploited and has been naturally taken, as local people use it for various purposes like food, timber and fuel, although, no management or conservation efforts have been established. The present study was conducted in this arid area of Western Rajasthan (India) with the aim to obtain preliminary molecular information about this group of plants. We evaluated diversity among 46 samples of C. decidua using chemical parameters and random amplified polymorphic DNA (RAPD) markers. Fourteen chemical parameters and eight minerals (total 22 variables) of this species fruits were estimated. A total of 14 RAPD primers produced 235 band positions, of which 81.27% were polymorphic. Jaccard's similarity coefficients for RAPD primers ranged from 0.34 to 0.86 with a mean genetic similarity of 0.50. As per observed coefficient of variation, NDF (Neutral Detergent Fiber) content was found to be the most variable trait followed by starch and soluble carbohydrate. The Manhattan dissimilarity coefficient values for chemical parameters ranged between 0.02-0.31 with an average of 0.092. The present study revealed a very low correlation (0.01) between chemical parameters and RAPD-based matrices. The low correlation between chemical- and RAPD-based matrices indicated that the two methods were different and highly variable. The chemical-based diversity will assist in selection of nutritionally rich samples for medicinal purpose, while genetic diversity to face natural challenges and find sustainable ways to promote conservation for future use. PMID:23894984

  11. Geochemical record of Late Quaternary paleoclimate from lacustrine sediments of paleo-lake San Felipe, western Sonora Desert, Mexico

    NASA Astrophysics Data System (ADS)

    Roy, P. D.; Caballero, M.; Lozano, R.; Ortega, B.; Lozano, S.; Pi, T.; Israde, I.; Morton, O.

    2010-04-01

    Stratigraphy, mineralogy, major and trace elements, organic carbon, carbonate, sulfate and AMS 14C dates are used to infer Late Quaternary depositional environments and paleo-hydrological conditions in the paleo-lake San Felipe located in the western part of Sonora Desert. Sediment stratigraphy divides the depth profile into aeolian and pluvio-lacustrine regimes. Aeolian regime is constrained to >44.5 14C kyr BP. The pluvio-lacustrine regime consists of two stratigraphic units with characteristic geochemical proxies indicating changing chemical weathering, clastic input, salinity and provenance and provides a measure of varying climatic conditions between ca. 37 and 3 14C kyr BP. Lower catchment erosion and inflow into the basin, higher lake productivity, precipitation of Na-sulfate mineral and higher clastic input from the proximal aeolian deposits during ca. 37-14 14C kyr BP are comparable to the regional registers of dominant winter rainfall related to westerly storm tracks and colder conditions. In the last 12 14C kyr BP, higher sedimentation and inflow and lower productivity are comparable to dominant summer rainfall. Higher humidity and lake productivity during ca. 37-29 14C kyr BP is possibly due to the position of westerly storm tracks at 31°N and the gradually reducing humidity till ca. 14 14C kyr BP is related to northerly migration of westerly storm tracks. Regional arid conditions during ca. 11 14C kyr BP and ca. 6 14C kyr BP are characterized by influx of coarser quartz and feldspars into the basin.

  12. Methanogens at the top of the world: occurrence and potential activity of methanogens in newly deglaciated soils in high-altitude cold deserts in the Western Himalayas

    PubMed Central

    Aschenbach, Katrin; Conrad, Ralf; Řeháková, Klára; Doležal, Jiří; Janatková, Kateřina; Angel, Roey

    2013-01-01

    Methanogens typically occur in reduced anoxic environments. However, in recent studies it has been shown that many aerated upland soils, including desert soils also host active methanogens. Here we show that soil samples from high-altitude cold deserts in the western Himalayas (Ladakh, India) produce CH4 after incubation as slurry under anoxic conditions at rates comparable to those of hot desert soils. Samples of matured soil from three different vegetation belts (arid, steppe, and subnival) were compared with younger soils originating from frontal and lateral moraines of receding glaciers. While methanogenic rates were higher in the samples from matured soils, CH4 was also produced in the samples from the recently deglaciated moraines. In both young and matured soils, those covered by a biological soil crust (biocrust) were more active than their bare counterparts. Isotopic analysis showed that in both cases CH4 was initially produced from H2/CO2 but later mostly from acetate. Analysis of the archaeal community in the in situ soil samples revealed a clear dominance of sequences related to Thaumarchaeota, while the methanogenic community comprised only a minor fraction of the archaeal community. Similar to other aerated soils, the methanogenic community was comprised almost solely of the genera Methanosarcina and Methanocella, and possibly also Methanobacterium in some cases. Nevertheless, ~103 gdw−1 soil methanogens were already present in the young moraine soil together with cyanobacteria. Our results demonstrate that Methanosarcina and Methanocella not only tolerate atmospheric oxygen but are also able to survive in these harsh cold environments. Their occurrence in newly deglaciated soils shows that they are early colonizers of desert soils, similar to cyanobacteria, and may play a role in the development of desert biocrusts. PMID:24348469

  13. Methanogens at the top of the world: occurrence and potential activity of methanogens in newly deglaciated soils in high-altitude cold deserts in the Western Himalayas.

    PubMed

    Aschenbach, Katrin; Conrad, Ralf; Reháková, Klára; Doležal, Jiří; Janatková, Kateřina; Angel, Roey

    2013-01-01

    Methanogens typically occur in reduced anoxic environments. However, in recent studies it has been shown that many aerated upland soils, including desert soils also host active methanogens. Here we show that soil samples from high-altitude cold deserts in the western Himalayas (Ladakh, India) produce CH4 after incubation as slurry under anoxic conditions at rates comparable to those of hot desert soils. Samples of matured soil from three different vegetation belts (arid, steppe, and subnival) were compared with younger soils originating from frontal and lateral moraines of receding glaciers. While methanogenic rates were higher in the samples from matured soils, CH4 was also produced in the samples from the recently deglaciated moraines. In both young and matured soils, those covered by a biological soil crust (biocrust) were more active than their bare counterparts. Isotopic analysis showed that in both cases CH4 was initially produced from H2/CO2 but later mostly from acetate. Analysis of the archaeal community in the in situ soil samples revealed a clear dominance of sequences related to Thaumarchaeota, while the methanogenic community comprised only a minor fraction of the archaeal community. Similar to other aerated soils, the methanogenic community was comprised almost solely of the genera Methanosarcina and Methanocella, and possibly also Methanobacterium in some cases. Nevertheless, ~10(3) gdw(-1) soil methanogens were already present in the young moraine soil together with cyanobacteria. Our results demonstrate that Methanosarcina and Methanocella not only tolerate atmospheric oxygen but are also able to survive in these harsh cold environments. Their occurrence in newly deglaciated soils shows that they are early colonizers of desert soils, similar to cyanobacteria, and may play a role in the development of desert biocrusts. PMID:24348469

  14. Phylogeny, divergence times and species limits of spiny lizards (Sceloporus magister species group) in western North American deserts and Baja California.

    PubMed

    Leaché, Adam D; Mulcahy, Daniel G

    2007-12-01

    The broad distribution of the Sceloporus magister species group (squamata: phrynosomatidae) throughout western North America provides an appropriate model for testing biogeographical hypotheses explaining the timing and origins of diversity across mainland deserts and the Baja California Peninsula. We inferred concordant phylogenetic trees describing the higher-level relationships within the magister group using 1.6 kb of mitochondrial DNA (mtDNA) and 1.7 kb of nuclear DNA data. These data provide strong support for the parallel divergence of lineages endemic to the Baja California Peninsula (S. zosteromus and the orcutti complex) in the form of two sequential divergence events at the base of the magister group phylogeny. A relaxed phylogenetic analysis of the mtDNA data using one fossil and one biogeographical constraint provides a chronology of these divergence events and evidence that further diversification within the Baja California clades occurred simultaneously, although patterns of geographical variation and speciation between clades differ. We resolved four major phylogeographical clades within S. magister that (i) provide a novel phylogenetic placement of the Chihuahuan Desert populations sister to the Mojave Desert; (ii) illustrate a mixed history for the Colorado Plateau that includes Mojave and Sonoran Desert components; and (iii) identify an area of overlap between the Mojave and Sonoran Desert clades near Yuma, Arizona. Estimates of bidirectional migration rates among populations of S. magister using four nuclear loci support strong asymmetries in gene flow among the major mtDNA clades. Based on the nonexclusivity of mtDNA haplotypes, nuclear gene flow among populations and wide zones of phenotypic intergradation, S. magister appears to represent a single geographically variable and widespread species. PMID:17944851

  15. Remote sensing and geochemical investigations of selected surface processes in Egypt and Missouri

    NASA Astrophysics Data System (ADS)

    Crombie, Mary Katherine

    This thesis consists of three studies of surface processes on Earth: 1. Age and isotopic constraints of pluvial episodes in the Western Desert of Egypt. North Africa has undergone drastic climatic change over the past several hundred thousand years. Timing of humid intervals called pluvials was investigated by uranium- series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. Stable oxygen isotopes of the travertines were used in equilibrium oxygen isotope fractionation calculations indicating the Kurkur travertines have δ18O values similar to ancient Western Desert groundwaters (~[- ]11/perthous). The ages of the of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during periods of enhanced northern summer insolation. 2. Identification of soil moisture as an environmental risk factor for filariasis in Egypt. Bancroftian filariasis is a deforming illness transmitted by mosquitoes (Culex. pipiens) and caused by the parasite Wuchereria bancrofti (WHO technical report 821; Neva and Brown, 1994). Environmental variables, such as humidity, play an important role in the transmission cycle of filariasis. Landsat Thematic Mapper data were used to model the surface soil moisture conditions of the southern Nile Delta region of Egypt as a proxy for environmental humidity. Filariasis infection rates were found to be negligible for areas with low surface soil moisture availability (>20%). Variable infection rates were observed for regions with higher surface soil moisture content, possibly due to anthropogenic influences such as insect control and the use of anti- filarial drugs. 3. Monitoring of Pb aerosol fallout in the vicinity of the Glover smelter, Southeastern

  16. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  17. PIXE micro-mapping of minor elements in Hypatia, a diamond bearing carbonaceous stone from the Libyan Desert Glass area, Egypt: Inheritance from a cold molecular cloud?

    NASA Astrophysics Data System (ADS)

    Andreoli, M. A. G.; Przybylowicz, W. J.; Kramers, J.; Belyanin, G.; Westraadt, J.; Bamford, M.; Mesjasz-Przybylowicz, J.; Venter, A.

    2015-11-01

    Matter originating from space, particularly if it represents rare meteorite samples, is ideally suited to be studied by Particle Induced X-ray Emission (PIXE) as this analytical technique covers a broad range of trace elements and is per se non-destructive. We describe and interpret a set of micro-PIXE elemental maps obtained on two minute (weighing about 25 and 150 mg), highly polished fragments taken from Hypatia, a controversial, diamond-bearing carbonaceous pebble from the SW Egyptian desert. PIXE data show that Hypatia is chemically heterogeneous, with significant amounts of primordial S, Cl, P and at least 10 elements with Z > 21 (Ti, V, Cr, Mn, Fe, Ni, Os, Ir) locally attaining concentrations above 500 ppm. Si, Al, Ca, K, O also occur, but are predominantly confined to cracks and likely represent contamination from the desert environment. Unusual in the stone is poor correlation between elements within the chalcophile (S vs. Cu, Zn) and siderophile (i.e.: Fe vs. Ni, Ir, Os) groups, whereas other siderophiles (Mn, Mo and the Platinum group elements (PGEs)) mimic the distribution of lithophile elements such as Cr and V. Worthy of mention is also the presence of a globular domain (Ø ∼ 120 μm) that is C and metals-depleted, yet Cl (P)-enriched (>3 wt.% and 0.15 wt.% respectively). While the host of the Cl remains undetermined, this chemical unit is enclosed within a broader domain that is similarly C-poor, yet Cr-Ir rich (up to 1.2 and 0.3 wt.% respectively). Our data suggest that the pebble consists of shock-compacted, primitive carbonaceous material enriched in cold, pre-solar dust.

  18. Spotlight: Egypt.

    PubMed

    1998-12-01

    Egypt is the most populous country in the Arab world and the second most populous country in Africa, with 65.5 million people living in a land area of 384,344 square miles as of mid-1998. There were 28 births and 6 deaths per 1000 population, as well as 63 infant deaths for every 1000 live births, and a population growing in size at 2.2% annually. The average Egyptian woman has 3.6 births during her reproductive lifetime and life expectancy is 65 years for men and 69 years for women. Egypt has major issues to address with regard to the management and use of its water resources, balancing the protection and use of rural lands, and expanding industry while protecting the air, water, and land. Much of Egypt's water is polluted and its soil damaged and depleted due to irrigation-related salinization. With Cairo and Alexandria already densely populated, the proportion of Egypt's population expected to live in urban areas should exceed 60% by 2025. Almost all of Egypt's population lives along the banks of the Nile and its delta, almost all of the country's agricultural production occurs on 5% of that land, and less than 1% of the land is protected. Population momentum will cause Egypt's population to grow a projected 51% by 2025 even though 47% of married women use some form of contraception. 51% of Egyptian adults are literate and tense relations with Israel influence Egypt's public expenditures and foreign assistance. PMID:12348893

  19. Timing and characteristics of Late Pleistocene and Holocene wetter periods in the Eastern Desert and Sinai of Egypt, based on 14C dating and stable isotope analysis of spring tufa deposits

    NASA Astrophysics Data System (ADS)

    Hamdan, Mohamed A.; Brook, George A.

    2015-12-01

    There is very little dated evidence on wet periods in the Eastern Desert and Sinai Peninsula of Egypt during the Late Pleistocene and Holocene. To obtain such information, we have studied the petrography, isotope geochemistry and AMS radiocarbon ages of mostly relict tufas deposited by springs draining perched ground water bodies in metamorphic and volcanic rocks. The tufas unconformably overly Precambrian basic igneous rocks (basalt, diabase and gabbro). As the ages of tufa carbonate are frequently older than the true ages of the deposits because of the incorporation of old, 14C-dead carbon, we have dated both the carbonate matrix and insoluble organic material of the tufas. These ages show that the tufas were largely formed during two broad time periods, the most recent from 12,058 to 6678 cal yr BP (African Humid Period), and the other from ˜31,200-22,500 cal yr BP, with preferential growth during the coldest times of this period namely during Heinrich Events 2 and 3 (H2 and H3) and the Last Glacial Maximum (LGM). The time span between 19,000-9000 cal yr BP, including the YD and H1, appears to have been relatively more arid than the earlier LGM or H2 periods or the later Holocene. The Late Pleistocene tufas are depleted in 18O relative to the Holocene tufas and were deposited at a lower temperature (˜14.0°-20.8 °C vs. 18.4°-23.4 °C). We believe that the Holocene tufas in the Sinai were formed by rainfall from the Mediterranean and those in the southern part of the Eastern Desert by African monsoon rainfall derived from the Red Sea-Gulf of Aden and Indian Ocean. In contrast, the moisture that fed the Late Pleistocene tufas, which are depleted in 18O relative to Holocene deposits, and progressively depleted from north to south, was probably brought by the Westerlies from the Atlantic-Mediterranean Sea when the Westerly circulation was pushed southwards during the coldest periods of the Late Pleistocene. Periods of tufa deposition correlate with major

  20. Spatial association of Neoproterozoic continental arc I-type and post-collision A-type granitoids in the Arabian-Nubian Shield: The Wadi Al-Baroud Older and Younger Granites, North Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    El-Bialy, Mohammed Zaky; Omar, Mohamed M.

    2015-03-01

    The Neoproterozoic basement of Wadi Al-Baroud area located at the northern Eastern Desert (ED) of Egypt, at the northernmost segment of the Arabian-Nubian Shield (ANS), is comprised of two different granite suites. A large batholith ascribed to the Older Granite suite, extends across the boundary between the northern and central ED, and is intruded by two isolated plutons of the Younger Granite suite. The Older Granite suite includes gray-colored, massive to gneissose, granodiorites to tonalites typically containing microgranular mafic enclaves. These are calc-alkaline, magensian, metaluminous I-type granitoids, with high Sr contents, and depleted in Rb, Nb, Y and REE. The Younger Granite suite plutons are pink to red, biotite and two-mica monzogranites. These are peraluminous A-type granites exhibiting a high-K calc-alkaline nature, and varying between ferroan and magnesian type granites. The A-type granites of the Younger Granite suite are enriched in Ga, Y, HFSE and REE elements, and depleted in the LILE elements Ba, Sr and Rb and transition metals Cr, Ni, Co, Sc and V. Magmatic saturation temperatures indicate early crystallization of apatite at high temperature in the metaluminous I-type Older Granite suite, while in the peraluminous A-type Younger Granites its crystallization occurs later after separation of zircon and monazite. The plutons of the Younger Granite suite were generated during the post-collisional stage of the northern ANS, following collision between the juvenile ANS crust and the pre-Neoproterozoic continental blocks of west Gondwana. The emplacement of the Older Granite suite took place earlier, within a normally mature continental arc prior to the collision. These pre-collision granitoids evolved through assimilation-fractional crystallization processes from mantle-derived parental magmas, which have interacted with crustal materials during ascent and storage. The post-collisional Younger Granite suite seems to have been derived by high

  1. Composition, age, and origin of the ~620 Ma Humr Akarim and Humrat Mukbid A-type granites: no evidence for pre-Neoproterozoic basement in the Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Ali, Kamal A.; Moghazi, Abdel-Kader M.; Maurice, Ayman E.; Omar, Sayed A.; Wang, Qiang; Wilde, Simon A.; Moussa, Ewais M.; Manton, William I.; Stern, Robert J.

    2012-10-01

    The Humr Akarim and Humrat Mukbid plutons, in the central Eastern Desert of Egypt, are late Neoproterozoic post-collisional alkaline A-type granites. Humr Akarim and Humrat Mukbid plutonic rocks consist of subsolvus alkali granites and a subordinate roof facies of albite granite, which hosts greisen and Sn-Mo-mineralized quartz veins; textural and field evidence strongly suggest the presence of late magmatic F-rich fluids. The granites are Si-alkali rich, Mg-Ca-Ti poor with high Rb/Sr (20-123), and low K/Rb (27-65). They are enriched in high field strength elements (e.g., Nb, Ta, Zr, Y, U, Th) and heavy rare earth elements (La n /Yb n = 0.27-0.95) and exhibit significant tetrad effects in REE patterns. These geochemical attributes indicate that granite trace element distribution was controlled by crystal fractionation as well as interaction with fluorine-rich magmatic fluids. U-Pb SHRIMP zircon dating indicates an age of ~630-620 Ma but with abundant evidence that zircons were affected by late corrosive fluids (e.g., discordance, high common Pb). ɛNd at 620 Ma ranges from +3.4 to +6.8 (mean = +5.0) for Humr Akarim granitic rocks and from +4.8 to +7.5 (mean = +5.8) for Humrat Mukbid granitic rocks. Some slightly older zircons (~740 Ma, 703 Ma) may have been inherited from older granites in the region. Our U-Pb zircon data and Nd isotope results indicate a juvenile magma source of Neoproterozoic age like that responsible for forming most other ANS crust and refute previous conclusions that pre-Neoproterozoic continental crust was involved in the generation of the studied granites.

  2. Spectroscopy of olivine basalts using FieldSpec and ASTER data: A case study from Wadi Natash volcanic field, south Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Madani, Ahmed

    2015-10-01

    This paper aims at revealing the spectral characteristics of the olivine basalts exposed at Wadi Natash area, Egypt, using FieldSpec spectroradiometer. It also evaluates band ratios and fusion techniques for mapping purposes using ASTER data. Several volcanic episodes occurred during Early- to Late-Cretaceous are recorded in the study area. Early-Cretaceous olivine basalts are highly carbonated. Late-Cretaceous eruptions took place throughout several volcanic cones aligned in NW direction. Based on FieldSpec measurements and petrographic data, two groups of olivine basalt namely `A' and `B' are recognized. Fresh olivine basalt (group A) is characterized by low flat spectral profile with overall low reflectance values (˜20%). Spectral profile of altered olivine basalt (group B) shows moderate reflectance values (˜37%) with four little absorption features around the 1.10, 1.40, 2.00 and 2.35 μm wavelength regions. These absorption features are attributed mainly to the presence of chlorite and carbonate alteration products as indicated by petrographic examination. ASTER false colour composite band ratio image (3/2:R, 8/1:G and 8/5:B) discriminates easily the fresh and altered basalts by deep blue and reddish blue colours respectively. Image fusion between previously mentioned FCC ratios image and high spatial resolution ASTER panchromatic image are carried out using brovey and HSV transformation methods. Visual and statistical assessment methods proved that HSV fusion image yields better image interpretability results compared to brovey image. It improves the spatial resolution of original FCC ratios image with acceptable spectral preservation. The present study proved the usefulness of FieldSpec spectral profiles and the processed ASTER data for discriminating different olivine basalt groups exposed at the study area.

  3. Thermodynamic modelling of Sol Hamed serpentinite, South Eastern Desert of Egypt: Implication for fluid interaction in the Arabian-Nubian Shield ophiolites

    NASA Astrophysics Data System (ADS)

    Abu-Alam, Tamer S.; Hamdy, Mohamed M.

    2014-11-01

    The Arabian-Nubian Shield is the largest tract of juvenile continental crust of the Neoproterozoic. This juvenile crust is composed of intra-oceanic island arc/back arc basin complexes and micro-continents welded together along sutures as the Mozambique Ocean was closed. Some of these sutures are marked by ophiolite decorated linear belts. The Sol Hamed ophiolite (808 ± 14 Ma) in southeastern Egypt at the Allaqi-Heiani-Onib-Sol Hamed-Yanbu arc-arc suture represents an uncommon example of rocks that might be less deformed than other ophiolites in the Arabian-Nubian Shield. In order to understand fluid-rock interactions before and during arc-arc collision, petrological, mineral chemistry, whole-rock chemistry and thermodynamic studies were applied to the Sol Hamed serpentinized ophiolitic mantle fragment. These studies reveal that the protolith had a harzburgite composition that probably originated as forearc mantle in the subducted oceanic slab. We propose that these rocks interacted with Ti-rich melts (boninite) in suprasubduction zone, which latter formed the Sol Hamed cumulates. Spinel's Cr# associated with the whole rock V-MgO composition suggest that the harzburgites are highly refractory residues after partial melting up to 29%. The melt extraction mostly occurred under reducing conditions, similar to peridotites recovered from the subducted lithosphere. Protolith alteration resulted from two stages of fluid-rock interaction. The first stage occurred as a result of infiltration of concentrated CO2-rich fluid released from carbonate-bearing sediments and altered basalt at the subduction zone. The alteration occurred during isobaric cooling at a pressure of 1 kbar. The fluid composition during the isobaric cooling was buffered by the metamorphic reactions. The second stage of fluid-rock interactions took place through prograde metamorphism. The increase in pressure during this stage occurred as a result of thrusting within the oceanic crust. In this process the

  4. Use of the subsurface thermal regime as a groundwater-flow tracer in the semi-arid western Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Zenhom E.; Bayumy, Dina A.

    2016-02-01

    Temperature profiles from 25 boreholes were used to understand the spatial and vertical groundwater flow systems in the Western Nile Delta region of Egypt, as a case study of a semi-arid region. The study area is located between the Nile River and Wadi El Natrun. The recharge areas, which are located in the northeastern and the northwestern parts of the study area, have low subsurface temperatures. The discharge areas, which are located in the western (Wadi El Natrun) and southern (Moghra aquifer) parts of the study area, have higher subsurface temperatures. In the deeper zones, the effects of faults and the recharge area in the northeastern direction disappear at 80 m below sea level. For that depth, one main recharge and one main discharge area are recognized. The recharge area is located to the north in the Quaternary aquifer, and the discharge area is located to the south in the Miocene aquifer. Two-dimensional groundwater-flow and heat-transport models reveal that the sealing faults are the major factor disturbing the regional subsurface thermal regime in the study area. Besides the main recharge and discharge areas, the low permeability of the faults creates local discharge areas in its up-throw side and local recharge areas in its down-throw side. The estimated average linear groundwater velocity in the recharge area is 0.9 mm/day to the eastern direction and 14 mm/day to the northwest. The average linear groundwater discharge velocities range from 0.4 to 0.9 mm/day in the southern part.

  5. Use of the subsurface thermal regime as a groundwater-flow tracer in the semi-arid western Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Zenhom E.; Bayumy, Dina A.

    2016-06-01

    Temperature profiles from 25 boreholes were used to understand the spatial and vertical groundwater flow systems in the Western Nile Delta region of Egypt, as a case study of a semi-arid region. The study area is located between the Nile River and Wadi El Natrun. The recharge areas, which are located in the northeastern and the northwestern parts of the study area, have low subsurface temperatures. The discharge areas, which are located in the western (Wadi El Natrun) and southern (Moghra aquifer) parts of the study area, have higher subsurface temperatures. In the deeper zones, the effects of faults and the recharge area in the northeastern direction disappear at 80 m below sea level. For that depth, one main recharge and one main discharge area are recognized. The recharge area is located to the north in the Quaternary aquifer, and the discharge area is located to the south in the Miocene aquifer. Two-dimensional groundwater-flow and heat-transport models reveal that the sealing faults are the major factor disturbing the regional subsurface thermal regime in the study area. Besides the main recharge and discharge areas, the low permeability of the faults creates local discharge areas in its up-throw side and local recharge areas in its down-throw side. The estimated average linear groundwater velocity in the recharge area is 0.9 mm/day to the eastern direction and 14 mm/day to the northwest. The average linear groundwater discharge velocities range from 0.4 to 0.9 mm/day in the southern part.

  6. Community composition, abundance and biomass of tintinnids (Ciliata: Protozoa) in the Western Harbour, south-eastern Mediterranean Sea, Egypt.

    PubMed

    Heneash, Ahmed M M; Abdel-Rahman, Nasser S; Gharib, Samiha M

    2015-08-01

    Seasonal variations in species composition, abundance and biomass of tintinnids (Protozoa: Ciliata) were investigated in the Western Harbour, seasonally during 2012. There were remarkable seasonal variations in environmental parameters, phytoplankton concentrations and abundance and biomass of tintinnids: highest in spring and lowest in autumn. Annual average abundance and biomass of tintinnids were 8.435 ind. l(-1) and 3.725 μg C l(-1), respectively. A total of 29 species of tintinnids belonging to 11 genera was identified. Of which, Tintinnopsis was the most abundant genus in terms of number of species (9), but Favella was the best quantitatively (89% of the total tintinnids). The overall mean abundance and biomass were highest (mean 24.415 ind. l(-1) and 10.355 μg C l(-1), respectively) during spring than the remaining seasons. Due to significant positive relationship between the total biomass of tintinnids and phytoplankton concentrations, food supply is not a problem for tintinnids harbouring in the Western Harbour. Hence, predation loss by meso- and macrozooplankton might be the possible reasons for the estimated low biomass of tintinnids in the present study. Some of the seasonal environmental factors as water salinity, nitrite, dissolved oxygen and pH values exert an influence on the species composition, abundance and biomass of tintinnids. PMID:26202815

  7. 76 FR 59682 - Desert Southwest Customer Service Region-Western Area Lower Colorado Balancing Authority-Rate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-27

    ..., DSW-EI2, DSW- SPR2, and DSW-SUR2 on June 26, 2006 (Rate Order No. WAPA-127, 71 FR 36332).\\1\\ These..., Extension of Rate Order No. WAPA-127 through September 30, 2013. 76 FR 28767, May 18, 2011. Desert Southwest... published on September 18, 1985 (50 FR 37835). Under Delegation Order Nos. 00-037.00 and 00-001.00C, 10...

  8. Effect of the temperature variation between Mediterranean Sea and Syrian deserts on the dust storm occurrence in the western half of Iran

    NASA Astrophysics Data System (ADS)

    Amanollahi, Jamil; Kaboodvandpour, Shahram; Qhavami, Samira; Mohammadi, Bakhtiyar

    2015-03-01

    Recent dust storms have caused crises in western Iran, which necessitate the prediction of these storms a few days before their occurrence. This is the first study of its type that analyzes the effect of temperature differences between the Mediterranean Sea surface and Syrian deserts (creation zone of the dusts storms) on the formation of dust storms in the west of Iran. The study also seeks to identify any changes in the atmospheric temperature created by the extreme dust storm of July 5, 2009 in west of Iran (Sanandaj City). In this study, the MODIS images from 2000 to 2008, and particulate matter data of the Sanandaj station from 2008 to 2012 were utilized to identify the dust storm days. The Mediterranean Sea surface temperature data were extracted from NOAA satellites for dust storm days up to four days preceding them. The web site of world weather was used to obtain the temperature of Damascus, Syria station as the selected land station. According to the results, significant differences were acquired between surface temperatures of Damascus station and the Mediterranean Sea in the dust storm days and up to three days before them. As the dust storm days approached, a rising trend was observed in changes of the temperature difference between land and sea. Thermal map analysis of the atmosphere of the Syrian deserts on July 5, 2009 showed significant decrease in the levels of 1000 hPa and 500 hPa but for the days preceding it no significant changes were observed. It can be concluded that the temperature difference between the Mediterranean Sea surface and the Syrian deserts four days before the dust storm occurrences is the important factor in predicting this event.

  9. Solar Energy for Rural Egypt

    NASA Astrophysics Data System (ADS)

    Abdelsalam, Tarek I.; Darwish, Ziad; Hatem, Tarek M.

    Egypt is currently experiencing the symptoms of an energy crisis, such as electricity outage and high deficit, due to increasing rates of fossil fuels consumption. Conversely, Egypt has a high solar availability of more than 18.5 MJ daily. Additionally, Egypt has large uninhabited deserts on both sides of the Nile valley and Sinai Peninsula, which both represent more than 96.5 % of the nation's total land area. Therefore, solar energy is one of the promising solutions for the energy shortage in Egypt. Furthermore, these vast lands are advantageous for commissioning large-scaled solar power projects, not only in terms of space availability, but also of availability of high quality silicon (sand) required for manufacturing silicon wafers used in photovoltaic (PV) modules. Also, rural Egypt is considered market a gap for investors, due to low local competition, and numerous remote areas that are not connected to the national electricity grid. Nevertheless, there are some obstacles that hinder the progress of solar energy in Egypt; for instance, the lack of local manufacturing capabilities, security, and turbulent market in addition to other challenges. This paper exhibits an experience of the authors designing and installing decentralized PV solar systems, with a total rated power of about 11 kW, installed at two rural villages in at the suburbs of Fayoum city, in addition to a conceptual design of a utility scale, 2 MW, PV power plant to be installed in Kuraymat. The outcomes of this experience asserted that solar PV systems can be a more technically and economically feasible solution for the energy problem in rural villages.

  10. Electrical resistivity mapping of the buried stream channel of the Canopic branch in the western Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    El-Gamili, M. M.; Shaaban, F. F.; El-Morsi, O. A.

    1994-08-01

    Buried stream channels, which can often be mapped accurately by resistivity, are favoured targets for exploration. Horizontal profiling, electrical soundings, or both, are generally used. In the western Nile Delta, the electrical sounding method was applied using a Schlumberger electrode array with the maximum AB distance being 200 m. The field survey was conducted along profiles extending NE-SW, perpendicular to the expected historical Canopic buried stream channel. About 107 vertical electrical soundings (VES) were measured along eleven profiles. The (VES) field curves were interpreted using the automatic interpretation method of Zohdy and Bisdorf (1989) in which a layered model is obtained directly from a digitized sounding curve. The interpreted results were correlated with borehole data to delineate the main lithological units and to help construct geoelectrical cross-sections based on layer thicknesses and their corresponding ranges in litho-resistivity. The lithological information from borehole data, surface geology and the present layer resistivities indicate three major lithofacies: Holocene clay and silt at the top, Pleistocene sands, and then gravelly sands and gravels (El-Tahrir gravels) at the bottom. From the thickness of the riverine topmost clay-silt facies and the paleotopograph of the Pleistocene sands, the buried stream channels can be delineated. It is evident that two streams existed for the defunct Canopic branch. These defunct streams are discussed and correlated with the historical records.

  11. Study of atmospheric scattering and absorbing aerosols at 550nm over nearby western Indian tropical sites of Thar Desert effected region

    NASA Astrophysics Data System (ADS)

    Vyas, B. M.; Saxenna, Abhishek; Panwar, Chhagan

    2016-05-01

    The first time experimental results based on spaced satellite observations of different kinds of aerosols properties have been described over two different contrast environmental conditions locations in western tropical Indian region specifically first at Jaisalmer (26.90°N, 69.90°E, 220 m above mean sea level (amsl)) located in central Thar dessert vicinity of western Indian site over Indian Thar Desert region and another at Udaipur (24.6° N, 73.7° E, 560 m amsl) site concerning to semi-urban and semi arid place of hilly areas. The daily values of aerosols optical depth absorption at 500nm (AOD abs 500nm), aerosols optical depth extinction at 500nm (AOD ext 500nm) along with aerosols optical depth at 500nmon (AOD 500nm) of eleven year period from Jan., 2004 to Dec., 2014 are basis of primary database of the present investigation. From the synthesis if the above database and the basis of rigorous statistical approach, following some of interesting facts are noted (i) larger annual monthly AOD variation of 0.93 is noted over JSM when compared to observed annual monthly change in AOD cycle, over UDP, of only 0.50 clearly indicating the more impact of desert influence activities about more than double times over JSM than UDP (ii) The higher abundance of absorbing aerosols occurrences about two time higher are seen in JSM in comparison to UDP. It indicates the clear evidence of strong optical absorption properties of useful solar mid visible wavelength at 550nm as the results of presence of more availability of dust aerosols as mineral natural type in pre-monsoon to post-monsoon over JSM which is also more predominant over JSM than the UDP region located far away from desert activity regime (iii) The greater sharing of extinction solar radiation effect on aerosols are more effective in pre-monsoon in UDP in reference to over JSM, where as in case of UDP, the aerosols effect through the scattering mechanism gradually reduce from monsoon to winter months as compared

  12. Ancient Egypt.

    ERIC Educational Resources Information Center

    Evers, Virginia

    This four-week fourth grade social studies unit dealing with religious dimensions in ancient Egyptian culture was developed by the Public Education Religion Studies Center at Wright State University. It seeks to help students understand ancient Egypt by looking at the people, the culture, and the people's world view. The unit begins with outlines…

  13. Late Cretaceous multicolored shales and phosphatic sedimentary rocks in Egypt

    SciTech Connect

    Glenn, C.R.; Garrison, R.E.; Arthur, M.A.

    1983-03-01

    Upper Cretaceous transitional fluvial to marine variegated shale (upper Nubia Formation) and the fully marine Duwi (phosphate) Formation occur as thin, widespread, shallow-marine deposits in an east-west-trending belt spanning the lower-middle latitudes of Egypt. On a larger scale, the phosphoritic rocks in Egypt represent but a small portion of a laterally extensive Middle Eastern-North African phosphogenic province of Upper Cretaceous-Lower Tertiary age that accounts for accumulation of minable marine phosphate in excess of 70 billion tons. Phosphorites, porcelanites/cherts, organic carbon-rich shales, glauconitic sandstones, and bioclastic and fine-grained carbonate rocks variously reflect major hemipelagic and shallow-water carbonate sedimentation. Biosiliceous hemipelagic deposits, now diagenetically altered to procelanite and chert, reflect low energy depositional conditions that were periodically interrupted by high energy, possibly storm-induced currents and/or down-slope redeposition. Both dark shales and porcelanites locally contain abundant organic matter and are commonly finely laminated. Porcelanites and black shales are phosphatic, containing phosphatic grains identical, morphologically and chemically, to those found in associated phosphorites, and are probably the source from which the phosphorites were derived. The organic carbon-rich shales of the Duwi Formation appear to be quite laterally extensive and may, depending on thermal maturity, represent potential hydrocarbon source rocks in other portions of the region (e.g., Western Desert, Gulf of Suez), where they are more deeply buried.

  14. Nile behaviour and Late Palaeolithic humans in Upper Egypt during the Late Pleistocene

    NASA Astrophysics Data System (ADS)

    Vermeersch, Pierre M.; Van Neer, Wim

    2015-12-01

    The reconstruction of the environment and the human population history of the Nile Valley during the Late Pleistocene have received a lot of attention in the literature thus far. There seems to be a consensus that during MIS2 extreme dry conditions prevailed over north-eastern Africa, which was apparently not occupied by humans. The Nile Valley seems to be an exception; numerous field data have been collected suggesting an important population density in Upper Egypt during MIS2. The occupation remains are often stratified in, or at least related to, aeolian and Nile deposits at some elevation above the present-day floodplain. They are rich in lithics and animal bones, mainly fish, illustrating the exploitation of the Nile Valley by the Late Palaeolithic inhabitants. The fluvial processes active during that period have traditionally been interpreted as a continuously rising highly braided river. In this paper we summarize the evidence thus far available for the Late Pleistocene on the population densities in the Nile Valley, and on the models of Nilotic behaviour. In the discussion we include data on the environmental conditions in Eastern Africa, on the aeolian processes in the Western Desert of Egypt derived from satellite images, 14C and OSL dates, in order to formulate a new model that explains the observed high remnants of aeolian and Nilotic deposits and the related Late Palaeolithic sites. This model hypothesizes that, during the Late Pleistocene, and especially the LGM, dunes from the Western Desert invaded the Nile Valley at several places in Upper Egypt. The much reduced activity of the White Nile and the Blue Nile was unable to evacuate incoming aeolian sand and, as a consequence, several dams were created in the Upper Egyptian Nile Valley. Behind such dams the created lakes offered ideal conditions for human subsistence. This model explains the occurrence of Late Palaeolithic hunter-fisher-gatherers in a very arid environment with very low Nile flows

  15. Groundwater studies in arid areas in Egypt using LANDSAT satellite images

    NASA Technical Reports Server (NTRS)

    Elshazly, E. M.; Abdelhady, M. A.; Elshazly, M. M.

    1977-01-01

    Various features are interpreted which have strong bearing on groundwater in the arid environment. These include the nature of geological and lithologic units, structural lineaments, present and old drainage systems, distribution and form of water pools, geomorphologic units, weathering surfaces and other weathering phenomena, desert soils, sand dunes and dune sand accumulations, growths of natural vegetation and agriculture, and salt crusts and other expressions of salinization. There are many impressive examples which illustrate the significance of satellite image interpretation on the regional conditions of groundwater which could be traced and interconnected over several tens or even several hundreds of kilometers. This is especially true in the northern Western Desert of Egypt where ground water issuing from deep strata comes to the surface along ENE-WSW and ESE-WNW fault lines and fracture systems. Another striking example is illustrated by the occurrence of fresh to brackish groundwater on the Mediterranean Sea Coastal Zone of the Western Desert where the groundwater is found in the form of lenses floating on the saline sea water.

  16. Mesozoic and Cenozoic thermal history of the eastern Mojave Desert, California and western Arizona, with emphasis on the Old Woman Mountains area and the Chemehuevi metamorphic core complex

    SciTech Connect

    Foster, D.A.

    1989-01-01

    Mesozoic thickening and Cenozoic extension resulted in the juxtaposition of upper and middle crustal rocks in the eastern Mojave Desert, southeastern California and western Arizona. The application of {sup 40}Ar/{sup 39}Ar thermochronology and petrology/thermobarometry to rocks in this region provides information about the timing and nature of thrusting, plutonism, metamorphism, denudation, and detachment faulting. Orogenesis culminated during the Late Cretaceous when rocks exposed in the Old Woman-Piute, Chemehuevi, and Sacramento Mountains attained temperatures > 500C. High grade metamorphism of the Old Woman Mountains area was caused by the intrusion of the Old Woman-Piute batholith at 73 {plus minus} 1 Ma; Cretaceous mineral assemblages in Proterozoic pelites increase in grade from greenschist to upper amphibolite facies, and {sup 40}Ar/{sup 39}Ar hornblende ages from Proterozoic amphibolites decrease in age from {approximately} 1,600 Ma to 73 {plus minus} 1 Ma, in the direction of 73 Ma plutons. Pluton emplacement and metamorphism occurred at 3 to 3.5 kbars and 400 > 600C in the Piute Mountains, and 3.5 to 4.5 kbars and 530 to > 650C in the Old Woman Mountains. Following the Cretaceous, the eastern Mojave Desert underwent a period of cooling at a rate of 2 to 10C/Ma between 65 and 25 Ma. By 30 Ma rocks exposed in the Old Woman-Piute, Marble Ship, Clipper and Turtle Mountains were below {approximately} 100C. {sup 40}/{sup 39}Ar ages from the Sacramento Mountains suggest that mylonitization caused by the onset of regional extension occurred at 23 {plus minus} 1 Ma. When extension started in the Chemehuevi Mountains, rocks exposed in the southwestern and northeastern portions of footwall to the Chemehuevi detachment fault were at {approximately} 180C and {approximately} 350C, respectively which suggests that this fault initiated at a dip of 5 to 30{degree}.

  17. The formation of the patterns of desert shrub communities on the Western Ordos Plateau, China: the roles of seed dispersal and sand burial.

    PubMed

    Wang, Yange; Yang, Xiaohui; Shi, Zhongjie

    2013-01-01

    The western Ordos Plateau is a key area of shrub diversity and a National Nature Reserve of endangered shrub species in north-west China. Desert expansion is becoming the most important threat to these endangered species. However, little is known about the effects of sand burial on the dynamics of the shrub community. This study aims to investigate how the shrubs as a community and as different individual shrubs respond to the disturbances caused by the desert expansion. The approach used by this study is to separate the seed-dispersal strategy from the sand-burial forces that are involved in structuring the shrub communities at different disturbance stages. Four communities for different disturbance stages were surveyed by using 50×50 m plots. The individual shrubs were classified into coloniser and successor groups at the seed-dispersal stage and strong and weak sand-burial tolerance groups at the sand-expansion stage. We employed spatial point pattern analysis with null models for each community to examine the seed-dispersal strategy and sand-burial forces affecting community distribution patterns. At the seed-dispersal stage, the interactions between the colonisers and the successors showed significant positive correlation at a scale of 0-1 m and significant negative correlation at a scale of 2 m; significant negative correlations between the groups with strong and weak sand-burial tolerance in the early stage of sand expansion at scales of 3-6 m, and significant positive correlation in the later stage of sand expansion at a scale of 13 m, were found. Seed-dispersal strategy is a reasonable mechanism to explain the shrub community pattern formation in the earlier stages, whereas sand burial is the primary reason for the disappearance of shrubs with weak sand-burial tolerance, this irreversible disturbance causes homogenisation of the community structure and produces aging populations of shrub species. This has an important influence on the succession direction

  18. The Formation of the Patterns of Desert Shrub Communities on the Western Ordos Plateau, China: The Roles of Seed Dispersal and Sand Burial

    PubMed Central

    Wang, Yange; Yang, Xiaohui; Shi, Zhongjie

    2013-01-01

    The western Ordos Plateau is a key area of shrub diversity and a National Nature Reserve of endangered shrub species in north-west China. Desert expansion is becoming the most important threat to these endangered species. However, little is known about the effects of sand burial on the dynamics of the shrub community. This study aims to investigate how the shrubs as a community and as different individual shrubs respond to the disturbances caused by the desert expansion. The approach used by this study is to separate the seed-dispersal strategy from the sand-burial forces that are involved in structuring the shrub communities at different disturbance stages. Four communities for different disturbance stages were surveyed by using 50×50 m plots. The individual shrubs were classified into coloniser and successor groups at the seed-dispersal stage and strong and weak sand-burial tolerance groups at the sand-expansion stage. We employed spatial point pattern analysis with null models for each community to examine the seed-dispersal strategy and sand-burial forces affecting community distribution patterns. At the seed-dispersal stage, the interactions between the colonisers and the successors showed significant positive correlation at a scale of 0–1 m and significant negative correlation at a scale of 2 m; significant negative correlations between the groups with strong and weak sand-burial tolerance in the early stage of sand expansion at scales of 3–6 m, and significant positive correlation in the later stage of sand expansion at a scale of 13 m, were found. Seed-dispersal strategy is a reasonable mechanism to explain the shrub community pattern formation in the earlier stages, whereas sand burial is the primary reason for the disappearance of shrubs with weak sand-burial tolerance, this irreversible disturbance causes homogenisation of the community structure and produces aging populations of shrub species. This has an important influence on the succession

  19. Evolution of rattlesnakes (Viperidae; Crotalus) in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change.

    PubMed

    Douglas, Michael E; Douglas, Marlis R; Schuett, Gordon W; Porras, Louis W

    2006-10-01

    During Pleistocene, the Laurentide ice sheet rearranged and diversified biotic distributions in eastern North America, yet had minimal physical impact in western North America where lineage diversification is instead hypothesized to result from climatic changes. If Pleistocene climatic fluctuations impacted desert species, the latter would reflect patterns of restricted gene flow concomitant with indications of demographic bottlenecks. Accordingly, molecular evidence for refugia should be present within these distributions and for subsequent range expansions as conditions improved. We sought answers to these questions by evaluating mitochondrial DNA (mtDNA) sequences from four species of rattlesnakes [Crotalus mitchellii (speckled rattlesnake), Crotalus cerastes (sidewinder), Crotalus tigris (tiger rattlesnake), Crotalus ruber (red diamond rattlesnake)] with distributions restricted to desert regions of southwestern North America. We inferred relationships using parsimony and maximum likelihood, tested intraspecific clades for population expansions, applied an isolation-with-migration model to determine bi-directional migration rates (m) among regions, and inferred divergence times for species and clades by applying a semiparametric penalized likelihood approach to our molecular data. Evidence for significant range expansion was present in two of eight regions in two species (Crotalus mitchellii pyrrhus, C. tigris region north). Two species (C. cerastes, C. mitchellii) showed a distribution concomitant with northward displacement of Baja California from mainland México, followed by vicariant separation into subclades. Effects of Pleistocene climate fluctuations were found in the distributions of all four species. Three regional diversification patterns were identified: (i) shallow genetic diversity that resulted from Pleistocene climatic events (C. tigris, C. ruber); (ii) deep Pleistocene divisions indicating allopatric segregation of subclades within refugia (C

  20. Integrated biostratigraphy, stage boundaries and Paleoclimatology of the Upper Cretaceous-Lower Eocene successions in Kharga and Dakhala Oases, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Khalil, H.; Al Sawy, S.

    2014-08-01

    The Upper Cretaceous-Lower Eocene succession in the studied sections is divided into four rock units that arranged from base to top: the Dakhla, Tarawan, Esna and the Thebes formations. Detailed study of the foraminifera and calcareous nannofossils has led to the recognition of 58 and 82 species, respectively. Based on planktonic foraminifera and calcareous nannofossils 8 planktonic foraminiferal biozones (CF4, P2, P3, P4, E1, E2, E3 and E4) have been recognized as well as 8 calcareous nannofossil biozones (CC25b, NP3, NP4, NP5, NP6, NP7/8, NP9, and NP10). At Gabal Teir/Tarawan section, Kharga Oasis, the Paleocene can be divided into three stages; Danian, Selandian and Thanetian. The Danian/Selandian boundary is placed at P3a/P3b zonal boundary (LO of Igorina albeari) which corresponds to the level of LO of Lithoptychius ulii, Fasciculithus pileatus, Fasciculithus involutus and Lithoptychius janii (upper part of Zone NP4). The Selandian/Thanetian boundary, on the other hand, can be traced within the foraminiferal Zone P4 (Globanomalina pseudomenardii Zone) and between the nannofossil zones NP6 and NP7/8 (LO of Discoaster mohleri). At Gabal Ghanima section, the Paleocene/Eocene boundary is located within the lower part of the Esna Formation. It can be traced at the base of planktonic foraminiferal Zone E1 (LOs of Acarinina africana, A sibaiyaensis and Morozovella allinsoensis), and at the NP9a/NP9b subzonal boundary (LO of Rhomboaster spp). However, the lower Eocene succession seems to be condensed and punctuated by minor hiatus (absence of Subzone NP10a). The dominance of cool water nannofossil species in the late Maastrichtian and early Danian interval suggests a gradual decrease in the surface water paleotemperature. However, a slight warming condition prevailed around the Danian/Selandian transition as evidenced by the warm water nannofossil species. At the P/E boundary interval, the high abundance of warm-water taxa (e.g. Discoaster, Sphenolithus, Rhomboaster, Tribrachiatus and Pontosphaera species) indicates a warm-water paleotemperatures.

  1. Application of high-pass filtering techniques on gravity and magnetic data of the eastern Qattara Depression area, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Zahra, Hesham Shaker; Oweis, Hesham T.

    2016-06-01

    In this work, a reconnaissance study is presented to delineate the subsurface tectonics and lithological inferences of the eastern area of Qattara Depression using the Bouguer gravity and aeromagnetic data. To achieve this goal, several transformation techniques and filtering processes are accomplished on these maps. At first, the total intensity aeromagnetic map is processed through the application of reduction to the magnetic north pole technique. The fast Fourier transform is carried out on the gravity and RTP magnetic data for establishing and defining the residual (shallow) sources. The frequency high-pass filtering is used to enhance the anomaly wavelengths associated with the shallow sources. The used processing techniques are the polynomial surface fitting enhancement, Laplacian, Strike Filtering, Enhancement Utilization, Suppression Utilization, Butterworth Filtering Utilization, Butterworth high-pass filter, Euler's deconvolution and forward modeling. The equivalent depths of the isolated short wavelength anomalies are 0.759 and 0.340 km below the flight surface, and the depths of the intermediate wavelength anomalies are 1.28 and 2.00 km for the gravity and magnetic data, respectively. Finally, the quantitative interpretations of the Bouguer gravity and RTP magnetic maps of the study area, reflect the occurrence of the various types of structures and their components. The main tectonic deformations of the study area have NNW-SSE, NNE-SSW, NE-SW, NW-SE and E-W trends.

  2. Comparative study of factors controlling the groundwater occurrence in Bir Kiseiba and Bir El Shab areas, south western desert, Egypt using hydrogeological and geophysical techniques

    NASA Astrophysics Data System (ADS)

    Abu Risha, U. A.; Al Temamy, A. M. M.

    2016-05-01

    This research presents a clear example of the significant role of basement relief on the formation of aquifers and the impact of geologic structures on groundwater occurrence. A basement relief map was constructed using the depth to basement data acquired from 20 vertical electrical soundings (VESes), 3 land magnetic profiles, and 27 drilled wells tapping the basement rocks in addition to the elevations of the basement outcrops in the area of study. The map shows three basins underlying the area. The geoelectric survey shows that these basins were formed as a result of series of step faults. The largest basin underlies El-Shab area. The medium basin underlies the area of Bir Kiseiba whereas the smallest one underlies Bir Abu El-Hussein area. The Nubian Sandstone aquifer occurs only in El-Shab basin whereas the other basins are filled completely with the confining layer of Kiseiba Formation. The depth to basement in El-Shab basin ranges from 11 m. (ves-20) to 197 m. (ves-1) m.b.g.s. The depth to basement in Kiseiba basin ranges from 20 m. (Bir Kurayim magnetic profile) to 122 m. (ves-13) m.b.g.s. The depth to basement in Abu El-Husein basin ranges from 0 (basement outcrops) to 64 m. (Abu El-Husein magnetic profile) m.b.g.s. The aquifer thickness ranges from 0 m (where the aquitard rests directly on the basement) to 153 m. (El Shab well No. 79). The aquifer is uncoformably overlain by Kiseiba Formation which represents the aquitard layer at Bir El-Shab. The thickness of the aquitard ranges from 0 (in areas covered by the Nubian Sandstone) to 120 m (ves-13). Each of the aquifer and aquitard consist of three layers. Two of the aquitard layers are water-bearing. However, the estimated transmissivity of the aquitard is very low (11.9 m2/d). The groundwater moves vertically into the overlying aquitard at Bir El-Shab and subsequently flows in concentric pattern into the surrounding areas. Faulting controls groundwater occurrence and quality. Some springs lie on the basement high associated with step faulting at the edges of El-Shab basin. An ENE low-salinity zone is associated with the basement high which separates El-Shab basin from Kiseiba basin. Focused groundwater recharge through the faults and fractures from paleo playas could be the mechanism of the formation of this anomaly. The isotope data shows local recharge of the groundwater most likely during the Pleistocene time. Two-dimension (2D) Electrical Resistivity Tomography (ERT) profiles reveal that the evaporation process has the main role in increasing the salinity of some water points. It is highly recommended to delineate the southern boundary of El-Shab basin which is expected to extend into Sudan.

  3. Morphology and development of pahoehoe flow-lobe tumuli and associated features from a monogenetic basaltic volcanic field, Bahariya Depression, Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Khalaf, Ezz El Din Abdel Hakim; Hammed, Mohamed Saleh

    2016-01-01

    The dimensions, landforms, and structural characteristics of pahoehoe flow-lobe tumuli from Bahariya Depression are collectively reported here for the first time. The flow-lobe tumuli documented here characterize hummocky flow surfaces. These tumuli are characterized by low, dome-like mounds, lava-inflation clefts, and squeeze ups. Flow-lobe tumuli are of various shapes and sizes, which are affected by the mechanism of inflation because they formed in response to the increase of pressure within the flow when the flow's crust becomes thicker. The tumuli often appear isolated or in small groups in the middle sectors of the lava flows, whereas in the distal sectors they form large concentration, suggesting the presence of complex lava tubes inside of the flow. Tumuli exhibited by El Bahariya lava flows are between 3.0 and 50 m in length and up to 5.0 m in height with lenticular geometry in aerial view. The flow emplacement of flow-lobe tumuli is controlled by variations in local characteristics such as nature of the substrate, flow orientation, slope, interferrence with other lobes, and rate of lava supply. Their presence generally towards the terminal ends of flow fields suggests that they seldom form over the clogged portions of distributary tubes or pathways. Thus, localized inflations that formed over blockages in major lava tubes result in formation of flow-lobe tumuli. The three-tiered (crust-core-basal zone) internal structure of the flow-lobe tumuli, resembling the typical distribution of vesicles in P-type lobes, confirms emplacement by the mechanism of inflation. All the available data show that the morphology and emplacement mechanism of the studied flow-lobe tumuli may be analogous to similar features preserved within topographically confined areas of the Hawaiian and Deccan hummocky lava flows. Considering the age of the studied volcanic fields (˜22 Ma) it is most probable that the structures described here may be amongst the oldest recognized examples of lava inflation.

  4. Comparative study of factors controlling the groundwater occurrence in Bir Kiseiba and Bir El Shab areas, south western desert, Egypt using hydrogeological and geophysical techniques

    NASA Astrophysics Data System (ADS)

    Abu Risha, U. A.; Al Temamy, A. M. M.

    2016-05-01

    This research presents a clear example of the significant role of basement relief on the formation of aquifers and the impact of geologic structures on groundwater occurrence. A basement relief map was constructed using the depth to basement data acquired from 20 vertical electrical soundings (VESes), 3 land magnetic profiles, and 27 drilled wells tapping the basement rocks in addition to the elevations of the basement outcrops in the area of study. The map shows three basins underlying the area. The geoelectric survey shows that these basins were formed as a result of series of step faults. The largest basin underlies El-Shab area. The medium basin underlies the area of Bir Kiseiba whereas the smallest one underlies Bir Abu El-Hussein area. The Nubian Sandstone aquifer occurs only in El-Shab basin whereas the other basins are filled completely with the confining layer of Kiseiba Formation. The depth to basement in El-Shab basin ranges from 11 m. (ves-20) to 197 m. (ves-1) m.b.g.s. The depth to basement in Kiseiba basin ranges from 20 m. (Bir Kurayim magnetic profile) to 122 m. (ves-13) m.b.g.s. The depth to basement in Abu El-Husein basin ranges from 0 (basement outcrops) to 64 m. (Abu El-Husein magnetic profile) m.b.g.s. The aquifer thickness ranges from 0 m (where the aquitard rests directly on the basement) to 153 m. (El Shab well No. 79). The aquifer is uncoformably overlain by Kiseiba Formation which represents the aquitard layer at Bir El-Shab. The thickness of the aquitard ranges from 0 (in areas covered by the Nubian Sandstone) to 120 m (ves-13). Each of the aquifer and aquitard consist of three layers. Two of the aquitard layers are water-bearing. However, the estimated transmissivity of the aquitard is very low (11.9 m2/d). The groundwater moves vertically into the overlying aquitard at Bir El-Shab and subsequently flows in concentric pattern into the surrounding areas. Faulting controls groundwater occurrence and quality. Some springs lie on the basement high associated with step faulting at the edges of El-Shab basin. An ENE low-salinity zone is associated with the basement high which separates El-Shab basin from Kiseiba basin. Focused groundwater recharge through the faults and fractures from paleo playas could be the mechanism of the formation of this anomaly. The isotope data shows local recharge of the groundwater most likely during the Pleistocene time. Two-dimension (2D) Electrical Resistivity Tomography (ERT) profiles reveal that the evaporation process has the main role in increasing the salinity of some water points. It is highly recommended to delineate the southern boundary of El-Shab basin which is expected to extend into Sudan.

  5. AIRSAR Data for Geological and Geomorphological Mapping in the Great Sandy Desert and Pilbara Regions of Western Australia

    NASA Technical Reports Server (NTRS)

    Tapley, Ian J.

    1996-01-01

    Enhancements of AIRSAR data have demonstrated the benefits of synthetic aperture radar (SAR) for revealing an additional and mich higher level of information about the composition of the terrain than enhancements f either SPOT-PAN or Landsat TM data. With appropriate image processing techniques, surface and near surface geological structures, hydrological systems (both current and ancient) and landform features, have been evidenced in a diverse range of landscapes. In the Great Sandy Desert region where spectral variability is minimal, radar's sensitivity to the micromorphology of sparse exposures of subcrop and lag gravels has provided a new insight into the region's geological framework, its landforms, and their evolution. In the Pilbara region, advanced processing of AIRSAR data to unmix the backscatter between and within the three frequencies of data has highlighted subsurface extensions of greenstone lithologies below sand cover and morphological evidence of past flow conditions under former climate regimes. On the basis of these observations, it is recommend that radar remote sensing technology involving the use of high resolution, polarimetric data be seriously considered as a viable tool for exploration in erosional and depositional environments located within Australia's mineral and oil-prospective provinces.

  6. Impact of consecutive extreme rainstorm events on particle transport: Case study in a Sonoran Desert range, western USA

    NASA Astrophysics Data System (ADS)

    Dorn, Ronald I.

    2015-12-01

    Quantifying erosion rates in different landscape settings provides insight into how landforms change under different climatic, tectonic and anthropogenic influences. Sediment traps designed to capture grus detached from granitic hill crests of an arid Sonoran Desert mountain range were placed prior to every precipitation event over a three-year period, just above rills that drain areas between 18 and 68 m2. The slopes are underlain by moderately to strongly weathered granitic rocks to a depth of about a meter. Within this 3-year window, a 1000-year precipitation event followed 27 days later by a 500-year event detached granitic grus in amounts far greater than previous storms, capturing between 22 × and 63 × the average amount transported in the previous 59 rain events - indicating the non-linear nature of the response of grus detachment to precipitation intensity. Considering every precipitation event over a 3-year period, no detachment occurred from events with less than 2 mm of total rainfall, and only minimal erosion occurred from rainfall events with totals between 2 and 10 mm with durations typically less than 30 min. Detachment increased greatly with rain intensities of 36 mm/h or more. Grus detachment from these arid crests increases with drainage area, a higher percentage of exposed soil, and steeper slopes. 87Sr/86Sr ratios reveal that suspended sediment transported from hill crest to trap derives from recycled dust and not the local granite bedrock.

  7. Resilience to stress and disturbance, and resistance to Bromus tectorum l. invasion in cold desert shrublands of western North America

    USGS Publications Warehouse

    Chambers, Jeanne C.; Bradley, Bethany A.; Brown, Cynthia S.; D'Antonio, Carla; Germino, Matthew J.; Grace, James B.; Hardegree, Stuart P.; Miller, Richard F.; Pyke, David A.

    2013-01-01

    Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystems to stress and disturbance, and resistance to invasion. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked questions about (a) ecosystem attributes that determine resilience and resistance along environmental gradients, (b) effects of disturbances like livestock grazing and altered fire regimes and of stressors like rapid climate change, rising CO2, and N deposition on resilience and resistance, and (c) interacting effects of resilience and resistance on ecosystems with different environmental conditions. We conclude by providing strategies for the use of resilience and resistance concepts in a management context. At ecological site scales, state and transition models are used to illustrate how differences in resilience and resistance influence potential alternative vegetation states, transitions among states, and thresholds. At landscape scales management strategies based on resilience and resistance—protection, prevention, restoration, and monitoring and adaptive management—are used to determine priority management areas and appropriate actions.

  8. Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert, USA

    USGS Publications Warehouse

    Izbicki, J.A.; Radyk, J.; Michel, R.L.

    2002-01-01

    Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek Washes indicate that infiltration of streamflow occurs to depths below the root zone, and presumably to the water table, along much of Oro Grande Wash and near the mountain front along Sheep Creek Wash. Differences in infiltration at sites along each wash are the result of hydrologic variables such as proximity to the mountain front, quantity of streamflow, and texture of the subsurface deposits. Differences in infiltration between the washes are the result of large-scale geomorphic processes. For example, Oro Grande wash is incised into the Victorville fan and infiltration has occurred at approximately the same location over recent geologic time. In contrast, Sheep Creek Wash overlies an active alluvial fan and the stream channel can move across the fan surface through time. Infiltration does not occur to depths below the root zone at control sites outside of the washes.

  9. Data from a thick unsaturated zone underlying Oro Grande and Sheep Creek washes in the western part of the Mojave Desert, near Victorville, San Bernardino County, California

    USGS Publications Warehouse

    Izbicki, John A.; Clark, Dennis A.; Pimental, Maria I.; Land, Michael; Radyk, John C.; Michel, Robert L.

    2000-01-01

    This report presents data on the physical properties of unsaturated alluvial deposits and on the chemical and isotopic composition of soil water and soil gas collected at 12 monitoring sites in the western part of the Mojave Desert, near Victorville, California. Sites were installed using the ODEX air-hammer method. Seven sites were located in the active channels of Oro Grande and Sheep Creek Washes. The remaining five sites were located away from the active washes. Most sites were drilled to a depth of about 100 feet below land surface; two sites were drilled to the water table almost 650 feet below land surface. Drilling procedures, lithologic and geophysical data, and site construction and instrumentation are described. Core material was analyzed for water content, bulk density, water potential, particle size, and water retention. The chemical composition of leachate from almost 1,000 subsamples of cores and cuttings was determined. Water extracted from selected subsamples of cores was analyzed for tritium and the stable isotopes of oxygen and hydrogen. Water from suction-cup lysimeters and soil-gas samples also were analyzed for chemical and isotopic composition. In addition, data on the chemical and isotopic composition of bulk precipitation from five sites and on ground water from two water-table wells are reported.

  10. Cultural Diversity or Cultural Imperialism: Liberal Education in Egypt.

    ERIC Educational Resources Information Center

    Blanks, David R.

    1998-01-01

    A faculty member's experience at the American University in Cairo (Egypt) reveals that pluralism and tolerance are western concepts, even within the college curriculum. National identity affords cultural stability: where the American melting-pot experience is reinforced by the notion of cultural diversity, the national identity of Egypt is…

  11. Management of Egypt's Surface and Groundwater Resources: Present and Future

    NASA Astrophysics Data System (ADS)

    Sultan, M.; Ahmed, M.; Yan, E.; Milewski, A.; Mohamed, L.; Farag, A. Z. A.

    2014-12-01

    The River Nile is the main source of fresh water in Egypt. Most of Egypt's River Nile water (>85%) originates as precipitation over the Ethiopian highlands and is channeled by the Blue Nile. The construction (years: 2011 to 2017) of the Renaissance Dam (reservoir capacity: 70 x 109m3) on the Blue Nile poses an extreme threat to Egypt's population. If the reservoir was to be filled in 7 years, Egypt will lose (during each of 7 years following dam completion) a minimum of 15 x 109m3 of its annual allocation (55 x 109m3) to reservoir filling (10 x 109m3), evaporation (3.5 x 109m3), and infiltration (1.5 x 109m3). Three solutions are proposed: Solution I takes advantage of the cyclicity of Nile floods and is based on findings from a calibrated (against temporal head data) unconfined 2-dimensional transient groundwater flow model for Lake Nasser and surroundings and a calibrated (against lake levels) surface water model. Models show with time: (1) losses to infiltration will decrease (1975-193: 58.4 109m3; 1993-2001: 43.6 x 109m3) due to silting of Lake bottom and encroachment of excess Lake Nasser water will increase (e.g., 1975-1993: none; 1993-2001: 17 x 109m3). We propose to develop sustainable agricultural in the Western Desert: (1) In high flood years, excess Lake Nasser water (e.g., 1993-2001: 17 x 109m3) is channeled across the plateau bounding (from west) the River Nile valley to artificially recharge the Nubian Sandstone Aquifer System (NSAS) that crops out west of the plateau and, (2) in low flood years, we extract the recharged groundwater. Solution II calls on mining the NSAS at reasonable rates. Using temporal (January 2003 - September 2012) Gravity Recovery and Climate Experiment (GRACE) data we estimate the annual depletion rates at 2 x 109m3 due to artificial extraction (1.5 x 109m3) and natural discharge (0.5 x 109m3). Assuming current GRACE depletion rates, the recoverable groundwater (5,180 x 109m3) will last for 2500 years; if we were to quadruple

  12. Magnetic measurements with fluxgate 3-components magnetometers in archaeology. Multi-sensor device and associated potential field operators for large scale to centimetre investigations on the 1st millennium BC site of Qasr ʿAllam in the western desert of

    NASA Astrophysics Data System (ADS)

    Gavazzi, Bruno; Alkhatib-Alkontar, Rozan; Munschy, Marc; Colin, Frédéric; Duvette, Catherine

    2016-04-01

    Fluxgate 3-components magnetometers allow vector measurements of the magnetic field. Moreover, they are the magnetometers measuring the intensity of the magnetic field with the lightest weight and the lowest power consumption. Vector measurements make them the only kind of magnetometer allowing compensation of magnetic perturbations due to the equipment carried with the magnetometer. Fluxgate 3-components magnetometers are common in space magnetometry and in aero-geophysics but are never used in archaeology due to the difficulty to calibrate them. This problem is overcome by the use of a simple calibration and compensation procedure on the field developed initially for space research (after calibration and compensation, rms noise is less than 1 nT). It is therefore possible to build a multi-sensor (up to 8) and georeferenced device for investigations at different scales down to the centimetre: because the locus of magnetic measurements is less than a cubic centimetre, magnetic profiling or mapping can be performed a few centimetres outside magnetized bodies. Such an equipment is used in a context of heavy sediment coverage and uneven topography on the 1st millennium BC site of Qasr ʿAllam in the western desert of Egypt. Magnetic measurements with a line spacing of 0.5 m allow to compute a magnetic grid. Interpretation using potential field operators such as double reduction to the pole and fractional vertical derivatives reveals a widespread irrigation system and a vast cultic facility. In some areas, magnetic profiling with a 0.1 m line spacing and at 0.1 m above the ground is performed. Results of interpretations give enough proof to the local authorities to enlarge the protection of the site against the threatening progression of agricultural fields.

  13. Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis

    PubMed Central

    Barber, Carmel M.; Ahmad Rusmili, Muhamad Rusdi; Hodgson, Wayne C.

    2016-01-01

    Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins. PMID:26938558

  14. Sensitivity of growth and biomass allocation patterns to increasing nitrogen: a comparison between ephemerals and annuals in the Gurbantunggut Desert, north-western China

    PubMed Central

    Zhou, Xiaobing; Zhang, Yuanming; Niklas, Karl J.

    2014-01-01

    Background and Aims Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions. Methods Nitrogen was added to the soil at rates of 0, 0·5, 1·0, 3·0, 6·0 and 24·0 g N m−2 year−1. Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass. Key Results Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship. Conclusions These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric. PMID:24287812

  15. Fairy, tadpole, and clam shrimps (Branchiopoda) in seasonally inundated clay pans in the western Mojave Desert and effect on primary producers

    PubMed Central

    2010-01-01

    Background Fairy shrimps (Anostraca), tadpole shrimps (Notostraca), clam shrimps (Spinicaudata), algae (primarily filamentous blue-green algae [cyanobacteria]), and suspended organic particulates are dominant food web components of the seasonally inundated pans and playas of the western Mojave Desert in California. We examined the extent to which these branchiopods controlled algal abundance and species composition in clay pans between Rosamond and Rogers Dry Lakes. We surveyed branchiopods during the wet season to estimate abundances and then conducted a laboratory microcosm experiment, in which dried sediment containing cysts and the overlying algal crust were inundated and cultured. Microcosm trials were run with and without shrimps; each type of trial was run for two lengths of time: 30 and 60 days. We estimated the effect of shrimps on algae by measuring chlorophyll content and the relative abundance of algal species. Results We found two species of fairy shrimps (Branchinecta mackini and B. gigas), one tadpole shrimp (Lepidurus lemmoni), and a clam shrimp (Cyzicus setosa) in our wet-season field survey. We collected Branchinecta lindahli in a pilot study, but not subsequently. The dominant taxa were C. setosa and B. mackini, but abundances and species composition varied greatly among playas. The same species found in field surveys also occurred in the microcosm experiment. There were no significant differences as a function of experimental treatments for either chlorophyll content or algal species composition (Microcoleus vaginatus dominated all treatments). Conclusions The results suggest that there was no direct effect of shrimps on algae. Although the pans harbored an apparently high abundance of branchiopods, these animals had little role in regulating primary producers in this environment. PMID:21143855

  16. Ghetto poverty and pollution in Egypt: a deadly threat for western countries caused by new and infectious mutants. A cultural, social and microbiological synopsis.

    PubMed

    Wassili, J H; Baradaeus, Cyril

    2012-10-01

    Egypt, whose soil germinated the first civilization, monotheism, refined ethics and culture of sharing the abundance of extracted natural resources among its populace became the crucible proliferating de-novo genotypes of organic and moral maladies. The enigma is these mutations are synchronized by several factors, namely; failing medical health, if there is any, abundant filth, cultural bankruptcy, over population, dogmatic militarism, societal deprivation and characterization, etc. These domineering ingredients fossilized Egypt as of 1952 coup in an irrevocable national apoptosis, together with the crippled social justice and imbalanced distribution of wealth among Egyptians, rates of bacterial and viral evolution to second generation resistant to known medical interventions are expected to exponentially accelerate. Therefore, it deemed essential to elaborate on pollution and psychosis-induced inflammations and grievous crimes evoked by dogmatic cults at the breeding source, e.g., ghettos and sporadic locations of the homeless in Cairo, Alexandria and Upper Egyptian villages. While this second generation of viral and bacterial diseases could labor plagues threatening the precariously maintained so-called social fabric of Middle Eastern countries, that are uniquely segregating its populace according to their dogmatic affiliations and soaked into intolerance, it would definitely compromise the integrity of the expensively managed medical care system of developed countries. PMID:22762378

  17. Desert dust in rural western US; the influence of dust storms, large particles, and land-use change on aerosol loads

    NASA Astrophysics Data System (ADS)

    Parks, D.; MacDonald, A. E.; Rosen, R. D.; Edmonds, H. N.; Key, E.; Swanberg, N.; Wiseman, W. J.; Sandgathe, S. A.; Neff, J. C.; Fernandez, D.; Munson, S.; Reynolds, R. L.

    2011-12-01

    western US. Finally, the sources of large mineral aerosols are different from those of industrial aerosols that dominate urban areas, and thus the concentrations of large particles do not correspond with variations in urban concentrations of small industrial aerosols. Mineral aerosols are produced by both natural erosion of desert soils and the variety of human activities such as grazing, resource extraction, and recreation that lead to surface disturbance. In large areas of the rural West, resource extraction and recreational activities have been increasing leading to the potential for increases in mineral aerosol concentrations. Without improved monitoring capabilities that focus on these large particles, any potential long-term changes in large-particle aerosol loads in the rural west will continue to go undetected.

  18. Desert Communities.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides: (1) background information on desert communities, their similarities, and differences; (2) student activities on this topic; and (3) ready-to-copy student pages with pictures of desert animals and plants. Each activity includes objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. (DH)

  19. Desert Sojourn.

    ERIC Educational Resources Information Center

    Greenman, Geri

    1999-01-01

    Focuses on an activity in which the students in a beginning drawing class used middle-value brown paper and earthen shades of conte to draw pictures of bones in a desert environment. Discusses how the assignment teaches appreciation of the colors, sounds, and shapes of the desert. (CMK)

  20. Ancient Egypt

    NASA Astrophysics Data System (ADS)

    Swamy, Ashwin Balegar

    This thesis involves development of an interactive GIS (Geographic Information System) based application, which gives information about the ancient history of Egypt. The astonishing architecture, the strange burial rituals and their civilization were some of the intriguing questions that motivated me towards developing this application. The application is a historical timeline starting from 3100 BC, leading up to 664 BC, focusing on the evolution of the Egyptian dynasties. The tool holds information regarding some of the famous monuments which were constructed during that era and also about the civilizations that co-existed. It also provides details about the religions followed by their kings. It also includes the languages spoken during those periods. The tool is developed using JAVA, a programing language and MOJO (Map Objects Java Objects) a product of ESRI (Environmental Science Research Institute) to create map objects, to provide geographic information. JAVA Swing is used for designing the user interface. HTML (Hyper Text Markup Language) pages are created to provide the user with more information related to the historic period. CSS (Cascade Style Sheets) and JAVA Scripts are used with HTML5 to achieve creative display of content. The tool is kept simple and easy for the user to interact with. The tool also includes pictures and videos for the user to get a feel of the historic period. The application is built to motivate people to know more about one of the prominent and ancient civilization of the Mediterranean world.

  1. Whole-Genome Optical Mapping and Finished Genome Sequence of Sphingobacterium deserti sp. nov., a New Species Isolated from the Western Desert of China

    PubMed Central

    Molnár, István; Li, Xinna; Tang, Ran; Chen, Ming; Wang, Lin; Su, Shiyou; Zhang, Wei; Lin, Min

    2015-01-01

    A novel Gram-negative bacterium, designated ZWT, was isolated from a soil sample of the Western Desert of China, and its phenotypic properties and phylogenetic position were investigated using a polyphasic approach. Growth occurred on TGY medium at 5–42°C with an optimum of 30°C, and at pH 7.0–11.0 with an optimum of pH 9.0. The predominant cellular fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c or C16:1ω6c/C16:1ω7c) (39.22%), iso-C15:0 (27.91%), iso-C17:0 3OH (15.21%), C16:0 (4.98%), iso-C15:0 3OH (3.03%), C16:0 3OH (5.39%) and C14:0 (1.74%). The major polar lipid of strain ZWT is phosphatidylethanolamine. The only menaquinone observed was MK-7. The GC content of the DNA of strain ZWT is 44.9 mol%. rDNA phylogeny, genome relatedness and chemotaxonomic characteristics all indicate that strain ZWT represents a novel species of the genus Sphingobacterium. We propose the name S. deserti sp. nov., with ZWT (= KCTC 32092T = ACCC 05744T) as the type strain. Whole genome optical mapping and next-generation sequencing was used to derive a finished genome sequence for strain ZWT, consisting of a circular chromosome of 4,615,818 bp in size. The genome of strain ZWT features 3,391 protein-encoding and 48 tRNA-encoding genes. Comparison of the predicted proteome of ZWT with those of other sphingobacteria identified 925 species-unique proteins that may contribute to the adaptation of ZWT to its native, extremely arid and inhospitable environment. As the first finished genome sequence for any Sphingobacterium, our work will serve as a useful reference for subsequent sequencing and mapping efforts for additional strains and species within this genus. PMID:25830331

  2. Geochemical modeling of evaporation process in Lake Qarun, Egypt

    NASA Astrophysics Data System (ADS)

    Abdel Wahed, Mahmoud S. M.; Mohamed, Essam A.; El-Sayed, Mohamed I.; M'nif, Adel; Sillanpää, Mika

    2014-09-01

    Lake Qarun is an inland closed saline lake. It lies within the Fayoum Depression in the Western Desert of Egypt. Evaporation modeling has been carried out using PHREEQC to simulate the geochemical evolution of surface drainage waters inflow towards lake water. In the case of Lake Qarun, it is the first attempt to carry out such kind of modeling. Performance of this model helped to address the different sources of dissolved major ions to Lake Qarun and to identify the mechanisms control the lake's water chemistry. The model demonstrated that evaporation-crystallization process is the main mechanism controlling the evolution of lake water chemistry where major ions Na+, Mg2+, Cl- and SO42- have been built up in the lake by evaporation while Ca2+ and HCO3- are depleted by calcite precipitation. Moreover, the simulated model reproduced the real data observed in Lake Qarun except in the case of SO42- which is in real more enriched in the lake than the model output. The additional source of SO42- is reported to be from groundwater. The models result agreed well with the modified evolutionary Hardie and Eugster's scheme (1970) in which the final major composition of Lake Qarun water is Na-Mg-SO4-Cl type. In future, the monitoring of Lake Qarun chemistry with detection of any other sources of elements and/or local reactions inside the lake can be detected by performing the simulated evaporation model reported by the present study.

  3. Fracture types detected in eastern Mediterranean reservoirs (Turkey and Egypt)

    SciTech Connect

    Nurmi, R.; Taha, M.

    1988-08-01

    Most of Turkey's reservoirs are in the fractured Cretaceous Mardin Formation; however, new possibilities in fractured Paleozoic sandstones are being sought. The dominant fractures are fold related and are found on the northern flanks of the asymmetrical anticlines. The strike of these fractures is perpendicular to bedding planes and parallel to dip. There are fewer tear-fault-related and crestal-position fractures, but these may have a greater vertical extent. Fractures are present in all the producing areas of Egypt except the Nile delta. Basement fractures associated with shear zones in the southern Gulf of Suez have become an important exploration target. Fracture orientations are related to the major shear orientations except where later folding and faulting have caused structural rotation. The development of Zeit Bay field has shown that fractured basement rock can constitute a significant reservoir. The fracture reservoirs in northern Sinai and the Western Desert are in Cretaceous and Jurassic limestones and/or dolomitic limestones. The major shear fractures are parallel to the northwest-north-northwest compressive stresses that formed the reservoir structures; however, local fold- and fault-related fractures are also present.

  4. Lake Nasser and Toshka Lakes, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Nasser (center) and the Toshka Lakes (center left) glow emerald green and black in this MODIS true-color image acquired March 8, 2002. Located on and near the border of Egypt and Norther Sudan, these lakes are an oasis of water in between the Nubian (lower right) and Libyan Deserts (upper left). Also visible are the Red Sea (in the upper right) and the Nile River (running north from Lake Nasser). Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  5. Thar Desert

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This ASTER sub-scene covers an area of 12 x 15 km in NW India in the Thar Desert. The sand dunes of the Thar Desert constantly shift and take on new shapes. Located in northwestern India and eastern Pakistan, the desert is bounded on the south by a salt marsh known as the Rann of Kutch, and on the west by the Indus River plain. About 800 kilometers long and about 490 kilometers wide, the desert's terrain is mainly rolling sandhills with scattered growths of shrub and rock outcroppings. Only about 12 to 25 centimeters of rain fall on the desert each year, and temperatures rise as high as 52 degrees Celsius. Much of the population is pastoral, raising sheep for their wool. The image is located at 24.4 degrees north latitude and 69.3 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  6. Calcareous nannofossils and paleoenvironments of the Paleocene-Eocene thermal maximum (PETM) interval in central Egypt

    NASA Astrophysics Data System (ADS)

    Youssef, Mohamed

    2016-02-01

    The Paleocene-Eocene Thermal Maximum (PETM) interval was examined from four outcrops in Central Egypt to document the response of the floral communities across the PETM. The four outcrops are: Gebel Taramsa west of Qena, Gebel Duwi in the Red Sea Coast, and Gebel Qeryia, Gebel Arras sections in Wadi Qena. The qualitative and quantitative analyses of calcareous nannofossils used samples on a high resolution scale. The PETM is characterized by distinguished lithological succession, the Dababyia Quarry Beds (DQB) which extend over the Nile Valley, the Eastern Desert and the Western Desert. The calcareous nannofossils changes across the Paleocene/Eocene boundary (NP9a/NP9b) is marked by the following events: 1) abrupt decreases in both diversity and abundance, 2) dramatic decrease of Fasciculithus both in diversity and abundance, 3) first acme of Coccolithus pelagicus/Coccolithus subpertusus, and 4) first occurrence of excursion taxa including Discoaster araneus, Discoaster. anartios, Discoaster aegyptiacus and Rhomboaster spp). These events may refer to relatively warm and oligotrophic surface waters. The abundance of Toweius spp. in the upper part of the PETM which associated with Campylosphaera characterizes the return to normal conditions.

  7. Dust Plume off the Coast of Egypt

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Dwarfing the Nile, a river of dust flowed out of the deserts of northern Egypt on May 19, 2007. As the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite passed overhead at 12:05 p.m. local time in Cairo, the sensor captured this image of the dust spreading northward over the Mediterranean Sea from the sandy deserts that span the country. At the margins of the plume, ribbons and ripples of dust are translucent, allowing a glimpse of the desert and water beneath, but in the center, the cloud is opaque, revealing nothing of the surface below. The part of north-central Egypt hidden by the dust plume is the Qattara Depression, the country's lowest point. Dipping down to 133 meters below sea level (436 feet), the depression is home to sandy deserts and dry lake beds that occasionally flood. The sand and fine, lake bed sediments are easily lofted into the air by strong winds that scour the area in late winter and early spring. In the eastern (right-hand) part of the image, the Nile River is lined by narrow ribbons of dull green vegetation. The fan-shaped delta is dotted with tan-colored spots, marking the location of cities and towns. The Nile Valley and Delta make up only a small fraction of the country's total land area, yet they support almost the entire population. The large image provided above has a spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides this image in additional resolutions. The Earth Observatory also provides a 250-meter-resolution KMZ file of this image for use with Google Earth.

  8. Ancient Egypt: History 380.

    ERIC Educational Resources Information Center

    Turk, Laraine D.

    "Ancient Egypt," an upper-division, non-required history course covering Egypt from pre-dynastic time through the Roman domination is described. General descriptive information is presented first, including the method of grading, expectation of student success rate, long-range course objectives, procedures for revising the course, major course…

  9. Napoleon in Egypt.

    ERIC Educational Resources Information Center

    Fagan, Brian

    1989-01-01

    Recounts the 1798 Egyptian campaign of Napoleon Bonaparte, whose Scientific and Artistic Commission documented and described the glories of ancient Egypt. The expedition was a disaster by military standards, but the cultural legacies included the Rosetta Stone, and a chronicle entitled "Description de L'Egypte," which did much to popularize…

  10. Discovering Deserts.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1985-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Discovering Deserts." Contents are organized into the following sections: (1)…

  11. Desert Survivors!

    ERIC Educational Resources Information Center

    Horton, Jessica; Friedenstab, Steve

    2013-01-01

    This article describes a special third-grade classroom unit based on the reality show "Survivor." The goal of this engaging and interactive unit was to teach students about physical and behavioral adaptations that help animals survive in various desert biomes. The activity combines research, argument, and puppet play over one week of…

  12. Nile behaviour and Upper Palaeolithic humans in Upper Egypt

    NASA Astrophysics Data System (ADS)

    Vermeersch, Pierre M.

    2014-05-01

    There is evidence of a decreasing human occupation of the Upper Egyptian Nile valley during the MIS 5 to MIS 3 period. Whereas very large extraction sites of the Middle Stone Age have been recorded, only very few sites of the Upper Palaeolithic have been found. The best explanation of this fact is that during the Late Middle Stone Age and the Upper Palaeolithc there was nearly no need for raw materials because there was only a very restricted population present in Upper Egypt. From about 22 ka BP an important population increase is registered by the presence of numerous Late Palaeolithic sites. During the whole LGM there is abundant presence of humans along the Nile Valley in Upper Egypt. This population was mainly living from fishing. There seems to be an abrupt end of the Palaeolithic occupation after 12.8 ka BP. Until now, no sites were found in the Valley until some rare Epipaleolithic sites occur about 8.0 ka BP. It will be suggested that these population changes are influenced by the river Nile behaviour. The best interpretation of the observations in the Upper Egyptian Nile Valley is the hypothesis that at the same time that Nile flow was reduced because of the dryness in its source area, the impact of aeolian activity was increased over Northeast Africa. The increased aeolian activity by northern winds in the Fayum and Wadi Ryan during the LGM resulted in the accumulation of aeolian sand in the valley. That aeolian sand was transported along the western Nile valley cliffs until it was accumulated when the Nile Valley change it S-N direction, such as at Nag'Hammadi. At other places sand was invading the Nile valley, directly from the Western Desert, creating a damming of the Nile at several places such as Armant and Aswan. As Nile flow was quite reduced, the Nile was unable to erode all the incoming sand and the Nile water with its important clay content was dammed. At several places large lakes were created in the Nile Valley. Those lakes were an ideal

  13. Nummulite biostratigraphy of the Eocene succession in the Bahariya Depression, Egypt: Implications for timing of iron mineralization

    NASA Astrophysics Data System (ADS)

    Afify, A. M.; Serra-Kiel, J.; Sanz-Montero, M. E.; Calvo, J. P.; Sallam, E. S.

    2016-08-01

    In the northern part of the Bahariya Depression (Western Desert, Egypt) the Eocene carbonate succession, unconformably overlying the Cretaceous deposits, consists of three main stratigraphic units; the Naqb, Qazzun and El Hamra formations. The Eocene carbonates are relevant as they locally host a large economic iron mineralization. This work revises the stratigraphic attribution of the Eocene formations on the basis of larger benthic foraminifers from both carbonate and ironstone beds. Eight Nummulites species spanning the late Ypresian - early Bartonian (SBZ12 to SBZ17) were identified, thus refining the chronostratigraphic framework of the Eocene in that region of Central Egypt. Moreover, additional sedimentological insight of the Eocene carbonate rocks is presented. The carbonate deposits mainly represent shallow marine facies characteristic of inner to mid ramp settings; though deposits interpreted as intertidal to supratidal are locally recognized. Dating of Nummulites assemblages from the youngest ironstone beds in the mines as early Bartonian provides crucial information on the timing of the hydrothermal and meteoric water processes resulting in the formation of the iron ore mineralization. The new data strongly support a post-depositional, structurally-controlled formation model for the ironstone mineralization of the Bahariya Depression.

  14. Field and ASTER imagery data for the setting of gold mineralization in Western Allaqi-Heiani belt, Egypt: A case study from the Haimur deposit

    NASA Astrophysics Data System (ADS)

    Zoheir, Basem; Emam, Ashraf

    2014-11-01

    Although associated with carbonatized/listvenitized ophiolites and thrust structures, the morphology and internal structures of the auriferous quartz veins in the Haimur deposit suggest mineralization concurrent with NE-SW dextral brittle-ductile shear zones. The latter are attributed to intense transpression regime and are associated with (N)NE-trending tight to isoclinals folds that deform the early accretionary structures. Image processing techniques applicable to the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data are used for mapping structures and hydrothermal alteration associated with the Haimur deposit. The automated lineament extraction by LINE module on high resolution ASTER imagery provides efficient data for potential dilation loci. Emphasis is placed on reliability of mineral indices extracted from the ASTER band ratios for identification of possibly mineralized alteration zones associated with NE-trending shear zones. Field and remote sensing data, together with the structural fabrics along the lode-associated shear zones clearly constrain on the genetic relationship between the Haimur gold deposit and post-accretionary transpression/shearing. We conclude that hydrothermal alteration zones that are confined to tightly enfolded ophiolites and transpressive shear zones along the Western Allaqi-Heiani belt are most potential targets for new exploration plans.

  15. The Cretaceous glauconitic sandstones of Abu Tartur, Egypt

    NASA Astrophysics Data System (ADS)

    Pestitschek, Brigitte; Gier, Susanne; Essa, Mahmoud; Kurzweil, Johannes

    2010-05-01

    The Abu Tartur mine is located in the Western Desert of Egypt, 50 km west of El Kharga City. Geologically, the Abu Tartur plateau is built by a sequence of Upper Cretaceous (Campanian - Maastrichtian) phosphorites, black shales and glauconitic sandstones. The phosphate deposits are of great economic importance and have been mined since their discovery in 1967. Outcrop sections were measured, sampled, sedimentologically characterized and described. One specific glaucony layer was investigated mineralogically and chemically in detail and compared to a subsurface sample from the mine. Two depositional regimes can be interpreted based on sedimentary architecture and structures: 1) a deeper-water hemipelagic environment, where phosphorites and organic carbon-rich shales were deposited and 2) a shallower, prograding higher energy shelf environment with glauconies. From a sequence stratigraphic perspective 1) was deposited during the transgressive systems tract and the early highstand while 2) was deposited during the remaining highstand and a lowstand prograding wedge (Glenn & Arthur, 1990). Petrographic and SEM investigations show that the glaucony grains are of authochtonous origin. XRF, EMPA and thin-section analyses show that the glaucony grains from the outcrop differ significantly in their chemical composition, morphology and color from the grains of the mine sample. The fresh glauconies are enriched in Fe2O3 and K2O compared to the surface samples. XRD analyses of the clay fraction of the six outcrop samples and the mine sample show that the grains consist of illite(glauconite)/smectite mixed-layers, with more illite layers (80 %) in the mine sample. The charge distribution diagram muscovite-pyrophyllite-celadonite shows a clear trend from smectitic glaucony to illitic glaucony, the mine sample plots exactly in the field for glauconites. All these features indicate that the surface samples are strongly altered by weathering and that glauconite progressively

  16. What Makes a Desert a Desert?

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Presents background information and activities which focus on definition of a desert, locations of deserts, and factors influencing locations. Activities include objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. Two ready-to-copy pages with desert landforms and temperature/rainfall data are…

  17. Desert Test Site Uniformity Analysis

    NASA Technical Reports Server (NTRS)

    Kerola, Dana X.; Bruegge, Carol J.

    2009-01-01

    Desert test sites such as Railroad Valley (RRV) Nevada, Egypt-1, and Libya-4 are commonly targeted to assess the on-orbit radiometric performance of sensors. Railroad Valley is used for vicarious calibration experiments, where a field-team makes ground measurements to produce accurate estimates of top-of-atmosphere (TOA) radiances. The Sahara desert test sites are not instrumented, but provide a stable target that can be used for sensor cross-comparisons, or for stability monitoring of a single sensor. These sites are of interest to NASA's Atmospheric Carbon Observation from Space (ACOS) and JAXA's Greenhouse Gas Observation SATellite (GOSAT) programs. This study assesses the utility of these three test sites to the ACOS and GOSAT calibration teams. To simulate errors in sensor-measured radiance with pointing errors, simulated data have been created using MODIS Aqua data. MODIS data are further utilized to validate the campaign data acquired from June 22 through July 5, 2009. The first GOSAT vicarious calibration experiment was conducted during this timeframe.

  18. Desert test site uniformity analysis

    NASA Astrophysics Data System (ADS)

    Kerola, Dana X.; Bruegge, Carol J.

    2009-08-01

    Desert test sites such as Railroad Valley (RRV) Nevada, Egypt-1, and Libya-4 are commonly targeted to assess the on-orbit radiometric performance of sensors. Railroad Valley is used for vicarious calibration experiments, where a field-team makes ground measurements to produce accurate estimates of top-of-atmosphere (TOA) radiances. The Sahara desert test sites are not instrumented, but provide a stable target that can be used for sensor cross-comparisons, or for stability monitoring of a single sensor. These sites are of interest to NASA's Atmospheric Carbon Observation from Space (ACOS) and JAXA's Greenhouse Gas Observation SATellite (GOSAT) programs. This study assesses the utility of these three test sites to the ACOS and GOSAT calibration teams. To simulate errors in sensor-measured radiance with pointing errors, simulated data have been created using MODIS Aqua data. MODIS data are further utilized to validate the campaign data acquired from June 22 through July 5, 2009. The first GOSAT vicarious calibration experiment was conducted during this timeframe.

  19. Safsaf Oasis, Egypt

    NASA Technical Reports Server (NTRS)

    1998-01-01

    These images show two views of a region of south-central Egypt, each taken by a different type of spaceborne sensor. On the left is an optical image from the Landsat Thematic Mapper, and on the right is a radar image from the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR). This comparison shows that the visible and infrared wavelengths of Landsat are only sensitive to the materials on the surface, while the radar wavelengths of SIR-C/X-SAR can penetrate the thin sand cover in this arid region to reveal details hidden below the surface. Field studies in this area indicate that the L-band radar can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels, shown at the bottom of this image, are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. Only the most recently active channels are visible in the Landsat scene. Some geologic structures at the surface are visible in both images. However, many buried features, such as rock fractures and the blue circular granite bodies in the upper center of the image on the right, are visible only to the radar. The Safsaf Oasis is located near the bright yellow feature in the lower left center of the Landsat image. Scientists are using the penetrating capabilities of radar imaging in desert areas to study structural geology, mineral exploration, ancient climates, water resources and archaeology. Each image is 30.8 kilometers by 25.6 kilometers (19.1 miles by 15.9 miles) and is centered at 22.7 degrees north latitude, 29.3 degrees east longitude. North is toward the upper right. In the Landsat image, the colors are assigned as follows: red is Band 7 (mid-infrared); green is Band 4 (near infrared); and blue is Band 1 (visible blue light). The colors assigned to the radar frequencies and polarizations are as follows: red is L-band, horizontally transmitted and received; green

  20. Desert Dust Air Mass Mapping in the Western Sahara, using Particle Properties Derived from Space-based Multi-angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Fiebig, Marcus; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the SAhara Mineral dUst experiMent (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from Multi-angle Imaging SpectroRadiometer (MISR) observations, and to place the sub-orbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days for which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 to 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR's ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape, and single-scattering albedo. For the three study days, the satellite observations (a) highlight regional gradients in the mix of dust and background spherical particles, (b) identify a dust plume most likely part of a density flow, and (c) show an air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometers away.

  1. Phylogeographic Structure of a Tethyan Relict Capparis spinosa (Capparaceae) Traces Pleistocene Geologic and Climatic Changes in the Western Himalayas, Tianshan Mountains, and Adjacent Desert Regions

    PubMed Central

    Wang, Qian; Zhang, Ming-Li; Yin, Lin-Ke

    2016-01-01

    Complex geological movements more or less affected or changed floristic structures, while the alternation of glacials and interglacials is presumed to have further shaped the present discontinuous genetic pattern of temperate plants. Here we consider Capparis spinosa, a xeromorphic Tethyan relict, to discuss its divergence pattern and explore how it responded in a stepwise fashion to Pleistocene geologic and climatic changes. 267 individuals from 31 populations were sampled and 24 haplotypes were identified, based on three cpDNA fragments (trnL-trnF, rps12-rpl20, and ndhF). SAMOVA clustered the 31 populations into 5 major clades. AMOVA suggests that gene flow between them might be restricted by vicariance. Molecular clock dating indicates that intraspecific divergence began in early Pleistocene, consistent with a time of intense uplift of the Himalaya and Tianshan Mountains, and intensified in mid-Pleistocene. Species distribution modeling suggests range reduction in the high mountains during the Last Glacial Maximum (LGM) as a result of cold climates when glacier advanced, while gorges at midelevations in Tianshan appear to have served as refugia. Populations of low-altitude desert regions, on the other hand, probably experienced only marginal impacts from glaciation, according to the high levels of genetic diversity. PMID:27314028

  2. Desert Dust Aerosol Air Mass Mapping in the Western Sahara, Using Particle Properties Derived from Space-Based Multi-Angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Mueller, Detlef; Schladitz, Alexander; Von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the Sahara mineral dust experiment (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from multi-angle imaging spectroradiometer (MISR) observations, and to place the suborbital aerosol measurements into the satellite s larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR s ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape and single-scattering albedo. For the three study days, the satellite observations (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

  3. Phylogeographic Structure of a Tethyan Relict Capparis spinosa (Capparaceae) Traces Pleistocene Geologic and Climatic Changes in the Western Himalayas, Tianshan Mountains, and Adjacent Desert Regions.

    PubMed

    Wang, Qian; Zhang, Ming-Li; Yin, Lin-Ke

    2016-01-01

    Complex geological movements more or less affected or changed floristic structures, while the alternation of glacials and interglacials is presumed to have further shaped the present discontinuous genetic pattern of temperate plants. Here we consider Capparis spinosa, a xeromorphic Tethyan relict, to discuss its divergence pattern and explore how it responded in a stepwise fashion to Pleistocene geologic and climatic changes. 267 individuals from 31 populations were sampled and 24 haplotypes were identified, based on three cpDNA fragments (trnL-trnF, rps12-rpl20, and ndhF). SAMOVA clustered the 31 populations into 5 major clades. AMOVA suggests that gene flow between them might be restricted by vicariance. Molecular clock dating indicates that intraspecific divergence began in early Pleistocene, consistent with a time of intense uplift of the Himalaya and Tianshan Mountains, and intensified in mid-Pleistocene. Species distribution modeling suggests range reduction in the high mountains during the Last Glacial Maximum (LGM) as a result of cold climates when glacier advanced, while gorges at midelevations in Tianshan appear to have served as refugia. Populations of low-altitude desert regions, on the other hand, probably experienced only marginal impacts from glaciation, according to the high levels of genetic diversity. PMID:27314028

  4. Dwarfs in ancient Egypt.

    PubMed

    Kozma, Chahira

    2006-02-15

    Ancient Egypt was one of the most advanced and productive civilizations in antiquity, spanning 3000 years before the "Christian" era. Ancient Egyptians built colossal temples and magnificent tombs to honor their gods and religious leaders. Their hieroglyphic language, system of organization, and recording of events give contemporary researchers insights into their daily activities. Based on the record left by their art, the ancient Egyptians documented the presence of dwarfs in almost every facet of life. Due to the hot dry climate and natural and artificial mummification, Egypt is a major source of information on achondroplasia in the old world. The remains of dwarfs are abundant and include complete and partial skeletons. Dwarfs were employed as personal attendants, animal tenders, jewelers, and entertainers. Several high-ranking dwarfs especially from the Old Kingdom (2700-2190 BCE) achieved important status and had lavish burial places close to the pyramids. Their costly tombs in the royal cemeteries and the inscriptions on their statutes indicate their high-ranking position in Egyptian society and their close relation to the king. Some of them were Seneb, Pereniankh, Khnumhotpe, and Djeder. There were at least two dwarf gods, Ptah and Bes. The god Ptah was associated with regeneration and rejuvenation. The god Bes was a protector of sexuality, childbirth, women, and children. He was a favored deity particularly during the Greco-Roman period. His temple was recently excavated in the Baharia oasis in the middle of Egypt. The burial sites and artistic sources provide glimpses of the positions of dwarfs in daily life in ancient Egypt. Dwarfs were accepted in ancient Egypt; their recorded daily activities suggest assimilation into daily life, and their disorder was not shown as a physical handicap. Wisdom writings and moral teachings in ancient Egypt commanded respect for dwarfs and other individuals with disabilities. PMID:16380966

  5. The Politics of Educational Transfer and Policymaking in Egypt

    ERIC Educational Resources Information Center

    Ibrahim, Ali S.

    2010-01-01

    For the past two centuries, western modern education has informed education policies and practices in Egypt. However, few researchers have analyzed the historical or current politics of educational transfer in this country. This article investigates the ways in which foreign transfer has influenced Egyptian education, both historically and…

  6. Surgery in Egypt.

    PubMed

    el-Zawahry, M D; Ramzy, A F; el-Sahwi, E; Bahnasy, A F; Khafaga, M; Rizk-Allah, M A; Abou el-Hoda, M F

    1997-07-01

    The history of medicine can never be complete without referral to ancient Egyptian medicine. Imhotep has been identified as the god of medicine. There are 13 faculties of medicine in Egypt; the oldest is the Kasr El Aini Faculty, which started in 1925. We review undergraduate and postgraduate education in Egypt. The Egyptian Society of Surgeons organizes the scientific surgical activities. Schistosomiasis is a national health problem. Health care is provided by many types of hospitals, including university, teaching, Ministry of Public Health, military, and private hospitals. PMID:9230851

  7. Occupational health in Egypt.

    PubMed

    El-Ata, Gehad Ahmed Abo; Arnaout, Said N

    2002-01-01

    This review aims to evaluate current occupational health services (OHS) in Egypt. The authors begin with a background on the geography, population, and economy, and then briefly describe the labor force. They discuss the legislative aspects of OHS (including health insurance) and the environment; OHS training and education; and activities such as research, inspection, environmental monitoring, and management of occupational diseases. Occupational accidents and diseases, registered during 2000, are analyzed. Problems with OHS administration in Egypt are presented, along with relevant countermeasures. Various promotion and support measures for administrative policy are prioritized and discussed. PMID:12028958

  8. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  9. Nile Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Nile Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population of 57 million. The capital city of Cairo is at the apex of the delta in the middle of the scene. Across the river from Cairo can be seen the three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  10. Data from a Thick Unsaturated Zone Underlying Two Artificial Recharge Sites along Oro Grande Wash in the Western Part of the Mojave Desert, near Victorville, San Bernardino County, California, 2001-2006

    USGS Publications Warehouse

    Clark, Dennis A.; Izbicki, John A.; Johnson, Russell D.; Land, Michael

    2009-01-01

    This report presents data on the physical and hydraulic properties of unsaturated alluvial deposits and on the chemical and isotopic composition of water collected at two recharge sites in the western part of the Mojave Desert, near Victorville, California, from 2001 to 2006. Unsaturated-zone monitoring sites were installed adjacent to the two recharge ponds using the ODEX air-hammer and air rotary method to depths of about 460 feet and 269 feet below land surface. Each of the two unsaturated-zone monitoring sites included a water-table well, matric-potential sensors, and suction-cup lysimeters installed in a single bore hole. Drilling procedures, lithologic and geophysical data, and site construction and instrumentation are described. Core material was analyzed for water content, bulk density, water potential, particle size, and water retention. The chemical composition of leachate from almost 400 samples of cores and cuttings was determined. Water from suction-cup lysimeters also was analyzed for chemical and isotopic composition. In addition, data on the chemical and isotopic composition of groundwater from the two water-table wells are reported along with chemical and isotopic composition of the surface water in the recharge ponds.

  11. Desert Voices: Southwestern Children's Literature.

    ERIC Educational Resources Information Center

    Polette, Keith

    1997-01-01

    Examines three books with different ways of writing about the desert. Discusses: "Here Is the Southwestern Desert" by Madeline Dunphy, "The Desert Is My Mother" by Pat Mora, and "The Desert Mermaid" by Alberto Blanco. (PA)

  12. Ancient Egypt: Personal Perspectives.

    ERIC Educational Resources Information Center

    Wolinski, Arelene

    This teacher resource book provides information on ancient Egypt via short essays, photographs, maps, charts, and drawings. Egyptian social and religious life, including writing, art, architecture, and even the practice of mummification, is conveniently summarized for the teacher or other practitioner in a series of one to three page articles with…

  13. Egypt's National Education Debate.

    ERIC Educational Resources Information Center

    Cook, Bradley James

    2000-01-01

    Examines the vigorous dialectic occurring among intellectuals, religious leaders, and politicians trying to define the appropriate role of Islam in Egyptian education. Discusses the call for the Islamization of education in contemporary Egypt, aspects of Islamic law, the position of the state on religious education, and the influence of a small…

  14. Language Treatment in Egypt.

    ERIC Educational Resources Information Center

    Jernudd, Bjorn H.; Garrison, Gary L.

    This is a collection of eight essays dealing with various aspects of language treatment in Egypt. The first essay attempts a tentative typology characterizing the role of the Arabic language as a unifying or divisive force within and among the countries in which it is spoken as a native language. This essay also makes some initial reflections on…

  15. Reflections about bizarre mummification practices on mummies at Egypt's Dakhleh oasis: a review.

    PubMed

    Aufderheide, Arthur C

    2009-12-01

    About 100 mummified human remains were excavated from the Dakhleh Oasis in Egypt's Western Desert. Of these, less than half were examined by dissection. These dated to the Late Ptolemaic and Roman Periods. Initially, a confusing pattern of mortuary mummification practices was encountered that was identified ultimately as a product of primarily initial spontaneous mummification by desiccation. This was followed by tomb robbing in antiquity with unwrapping; body disarticulation followed, in turn, by mummy body reconstruction with atypical use of resin applications. Some of the resin was shown to be contaminated by bitumen that was responsible for inappropriately old radiocarbon dates of mummy tissue samples. Chemical reconstruction of diet using stable isotope ratios of carbon and nitrogen characterized their diet to be primarily that of C3 plants, consistent with trading records excavated from that site. Analysis of the mummy coprolites also enabled the first finding of the intestinal parasite Enterobius vermicularis in either ancient or modern Egyptian human coprolites. The principal focus of this report is to demonstrate and verify the value of including visceral dissection as part of a mummy examination whenever possible. PMID:20440958

  16. Statistical methods to study soil infiltration rate in Kharga Oasis, Egypt.

    NASA Astrophysics Data System (ADS)

    Gamie, Rasha; De Smedt, Florimond

    2016-04-01

    Agricultural expansion in the Kahrga oasis, located in the western desert of Egypt, strongly depends on irrigation. Hence, the infiltration rate is a key parameter for further development. The infiltration rate was measured in the field using a double ring infiltrometer at 20 m intervals in a 120 m by 120 m plot, together with 12 other relevant physical and chemical soil parameters. The resulting data were statistically analyzed using principal component and linear regression analyses. Results show that the infiltration rate is highly variable in the study area, and strongly positively correlated with hydraulic conductivity and negatively with silt, clay and carbonates contents of the soil. Principle component analysis showed that most of the variation in the data is assigned in the first 3 principle components. The first component explains 36% of the total variation and is strongly linked with soil structure; the second component explains 18% of the total variation and is linked to soil texture; the third component explains 13% and is linked to chemical properties but has no link with infiltration rate; all other components just represent noise in the data and must be attributed to measurement errors, randomness and soil heterogeneity. Multiple linear regression analysis shows that the only relevant factors to predict infiltration rate are hydraulic conductivity, and silt and carbonate content of the soil. The regression equation is only able to predict about half of the variation of the infiltrations rate, while the other half remains unexplained.

  17. SHUTTLE IMAGING RADAR PROVIDES FRAMEWORK FOR SUBSURFACE GEOLOGIC EXPLORATION IN EGYPT AND SUDAN.

    USGS Publications Warehouse

    Breed, Carol S.; McCauley, John F.; Schaber, Gerald G.

    1984-01-01

    Shuttle Imaging Radar provides a pictorial framework to guide exploration for mineral resources (potential placers), groundwater sources, and prehistoric archaeological sites in the Western Desert of Egypt and Sudan. Documented penetration by the SIR-A signal of dry surficial sediment to depths of a meter or more revealed bedrock geologic features and networks of former stream valleys otherwise concealed beneath windblown sand, alluvium, and colluvial deposits. 'Radar units' mapped on SIR-A images according to relative brightness and degree of mottling correspond to subsurface geologic and topographic features identified in more than 50 test pits. Petrologic examination of pit samples confirms that a variety of depositional environments existed in this now hyper-arid region before it was mantled by windblown sand sheets and dunes. Wet sand was discovered in two buried valleys shown on the radar images and located in the field with the aid of co-registered maps and Landsat images, and a satellite navigation device. Buried valleys whose streams once traversed mineralized zones are potential sites of placers (gold, tin).

  18. Recent environmental change and prehistoric human activity in Egypt and Northern Sudan

    NASA Astrophysics Data System (ADS)

    Nicoll, Kathleen

    2004-03-01

    This paper reviews the various Late Quaternary records that are available from western Egypt and northern Sudan, which includes more than 500 published radiocarbon dates and various sedimentary archives from local landscape components, including palaeolakes, soils, drainages (wadis), and archaeological sites. This palaeoenvironmental compilation frames the spatial and temporal context of local cultural activities when the region was most hospitable ˜9000-6000 BP; at this time, monsoonal weather influenced the portion of the African continental interior, creating enough convective rainfall for occasional surface water storage. In this part of the modern Sahara, rapid hydroclimatic changes play a key role in geomorphic evolution and resource availability. As 'watering holes' formed and dried up in the Early to Middle Holocene, Neolithic people developed various subsistence strategies, including opportunistic hunting of small animals (e.g. gazelle and hare), and food-related (e.g. wild sorghum, millet, and legumes) activities: gathering, plant cultivation and livestock-rearing. During its wettest phases during the 'monsoonal maximum,' the area was drought-prone, sustaining a meager steppe-shrub desert flora. Further desertification and aeolian deflation during the Middle and Late Holocene fostered technological innovation, migration and settlement, as well as the further development of agrarian communities and complex culture.

  19. Astronomy at Nabta Playa, Southern Egypt

    NASA Astrophysics Data System (ADS)

    McKim Malville, J.

    Nabta Playa may contain the oldest human-made features with astronomical alignments in Egypt. In the Late and Terminal Neolithic (7,500-5,400 BP), nomadic pastoralists built a ceremonial center on the western shore of Nabta Playa, consisting of some 30 complex megalithic structures, stone circles, and lines of megaliths crossing the playa. The megaliths may once have aligned with Arcturus, the Belt of Orion, Sirius, and α Cen. Reorientations of the northern set of megaliths suggest a response to precession. Elaborate burials at the nearby cemetery at Gebel Ramlah indicate the nomads consisted of Mediterranean and sub-Saharan populations with little social stratification.

  20. The Regional Environmental Impacts of Atmospheric Aerosols over Egypt

    NASA Astrophysics Data System (ADS)

    Zakey, Ashraf; Ibrahim, Alaa

    2015-04-01

    Identifying the origin (natural versus anthropogenic) and the dynamics of aerosols over Egypt at varying temporal and spatial scales provide valuable knowledge on the regional climate impacts of aerosols and their ultimate connections to the Earth's regional climate system at the MENA region. At regional scale, Egypt is exposed to air pollution with levels exceeding typical air-quality standards. This is particularly true for the Nile Delta region, being at the crossroads of different aerosol species originating from local urban-industrial and biomass-burning activities, regional dust sources, and European pollution from the north. The Environmental Climate Model (EnvClimA) is used to investigate both of the biogenic and anthropogenic aerosols over Egypt. The dominant natural aerosols over Egypt are due to the sand and dust storms, which frequently occur during the transitional seasons (spring and autumn). In winter, the maximum frequency reaches 2 to 3 per day in the north, which decreases gradually southward with a frequency of 0.5-1 per day. Monitoring one of the most basic aerosol parameters, the aerosol optical depth (AOD), is a main experimental and modeling task in aerosol studies. We used the aerosol optical depth to quantify the amount and variability of aerosol loading in the atmospheric column over a certain areas. The aerosols optical depth from the model is higher in spring season due to the impacts of dust activity over Egypt as results of the westerly wind, which carries more dust particles from the Libyan Desert. The model result shows that the mass load of fine aerosols has a longer life-time than the coarse aerosols. In autumn season, the modelled aerosol optical depth tends to increase due to the biomass burning in the delta of Egypt. Natural aerosol from the model tends to scatter the solar radiation while most of the anthropogenic aerosols tend to absorb the longwave solar radiation. The overall results indicate that the AOD is lowest in winter

  1. [Medical education in Egypt].

    PubMed

    Barnard, H

    2002-06-15

    Modern medical training in Egypt was started by Antoine Clot Bey in 1837 and became part of the university programme in 1919. At present, it comprises six years of university education, followed by one year of internships and one year of compulsory employment with a state-owned hospital. There are now 13 medical faculties in Egypt, using three different curricula: traditional, Islamic and innovative. Their implementation is hampered by the large number of students (15,500 men and 7500 women), the low salaries and motivation of the instructors, the teaching in English rather than Arabic and the lack of recent study materials. It is therefore rather difficult to compare the effectiveness of the Egyptian system with that in the Netherlands. Due partly to the differences in language and culture, Dutch authorities are reluctant to recognise Egyptian medical diplomas. PMID:12092309

  2. Anthropogenic wetlands due to over-irrigation of desert areas; A challenging hydrogeological investigation with extensive geophysical input

    NASA Astrophysics Data System (ADS)

    Behroozmand, A. A.; Teatini, P.; Pedersen, J. B. B.; Auken, E.; Tosatto, O.; Christiansen, A. V.

    2015-12-01

    During the last century, many large irrigation projects have been initiated in arid lands worldwide. Despite a tremendous increase in food production, a common problem when characterizing these zones is land degradation in form of waterlogging. As results, large volumes of water are lost due to surplus irrigation in regions where water availability is extremely challenging for both population survival and economic development. The Nubariya depression, Western Desert (Egypt), is a clear example of this mechanism. Following the reclamation of desert lands for agricultural production, an artificial brackish and contaminated lake developed in the area in the late 1990s and presently extends for about 2.5 km2. Available data provide evidence of a simultaneous general deterioration of the groundwater system. With the main objectives of understanding the hydrological evolution of the area, characterizing the hydrogeological setting and developing scenarios for artificial aquifer remediation and recharge, an extensive hydrogeophysical investigation was carried out in this challenging environment using Magnetic Resonance Sounding (MRS, also called surface NMR) and ground-based Transient EM (TEM). The integrated interpretation of the geophysical surveys, properly calibrated with a number of boreholes, provides a clear hydrogeological picture of the upper 100 m sedimentary structure, in terms of both lithology and groundwater quality. The information is then used to set up a regional groundwater flow and a local density-dependent flow and transport numerical model to reproduce the past evolution of the aquifer system and develop a few scenarios for artificial aquifer recharge using the treated waters provided by a nearby waste-water treatment plant. The research outcomes point the hydrological challenges that emerge for an effective management of water resources in reclaimed desert areas and highlight the effectiveness of integrating advanced geophysical and modeling

  3. Hydrogeochemical analysis and evaluation of groundwater in the reclaimed small basin of Abu Mina, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Zenhom E.; Atwia, Mohamed G.; El-Horiny, Mohamed M.

    2015-12-01

    Agricultural reclamation activities during the last few decades in the Western Nile Delta have led to great changes in the groundwater levels and quality. In Egypt, changing the desert land into agricultural land has been done using transferred Nile water (through irrigation canal systems) or/and groundwater. This research investigates the hydrogeochemical changes accompanying the reclamation processes in the small basin of Abu Mina, which is part of the Western Nile Delta region. In summer 2008, 23 groundwater samples were collected and groundwater levels were measured in 40 observation wells. Comparing the groundwater data of the pre-reclamation (1974) and the post-reclamation (2008) periods, groundwater seems to have been subjected to many changes: rise in water level, modification of the flow system, improvement of water quality, and addition of new salts through dissolution processes. Generally, Abu Mina basin is subdivided into two areas, recharge and discharge. The dissolution and mixing were recognized in the recharge areas, while the groundwater of the discharge region carries the signature of the diluted pre-reclamation groundwater. The salts of soil and aquifer deposits play an important role in the salt content of the post and pre-reclamation groundwater. NaCl was the predominant water type in the pre-reclamation groundwater, while CaSO4, NaCl and MgSO4 are the common chemical facies in the post-reclamation groundwater. The post-reclamation groundwater mostly indicates mixing between the pre-reclamation groundwater and the infiltrated freshwater with addition of some ions due to interaction with soil and sediments.

  4. New paleocene sepiid coleoids (cephalopoda) from Egypt: evolutionary significance and origin of the sepiid 'rostrum'.

    PubMed

    Košťák, Martin; Jagt, John W M; Speijer, Robert P; Stassen, Peter; Steurbaut, Etienne

    2013-01-01

    New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a 'rostrum-like' prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or 'rostrum-like' structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian-Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America. PMID:24348918

  5. [Sexuality in Ancient Egypt].

    PubMed

    Androutsos, G; Marketos, S

    1994-10-01

    The present article explores the sexuality in ancient Egypt. In particular in this article are presented the ways of concubinage (marriage, concubinage, adultery), the incest, loves of the pharaohs and of the common people, the freedom of choice in garments, the status of the hetairas and of the whores, the sexual perversions (male and female homosexuality, necrophilia, sodomism, bestiality, rape, masturbation, exhibitionism), the operations of the genitals (circumcision, excision, castration) and finally the level of knowledge in gynaecology, fertility, contraception and obstetrics that even today demands our admiration. PMID:7858632

  6. Egypt at the crossroads.

    PubMed

    Hinrichsen, D

    1992-01-01

    Egypt is the location of the 1994 International Population and Development Conference. Conditions in Egypt due to expected population growth rates are anticipated as headed for "ecological breakdown." There is loss of prime agricultural land to urban expansion and difficulties in providing employment and vital services. The fertility decline to 4 children/family is still inadequate to meet resource needs; a 2-child family norm must be adopted because the country can barely meet the needs of 90 million people. Cairo is becoming a mega-city of squatter settlements and slums. Population densities approach 140,000/sq. kilometers. The family planning (FP) program receives top political support. The contraceptive prevalence rate has risen to just over 50%, a 10% increase since 1988. Egypt is the first Muslim country to surpass the 50% mark. Credit for this accomplishment is given to public information and education campaigns to reduce family size, expansion of maternal and child health services and FP, the cooperation of Muslim clerics, and better educated women. Nongovernmental organizations have played an active role in FP. The future challenge is to improve services and outreach and keep up with demand. Attitudes in rural areas have changed, so that desiring children to help with farm work is the exception. Progress on arresting environmental destruction has not been as successful. There are still poor irrigation practices. The breadbasket the Nile River sustained no longer exists; Egypt is a net importer of food. Water shortages and water quality limit productivity. 57.2 billion cu. meters out of 58.4 billion cu. meters of freshwater available from the Nile River are used primarily for irrigation of the 17.6 million hectares of agricultural land along the river and its delta. Salts have polluted the river from fertilizers and pesticides and municipal and industrial wastes. Industrial dumping is illegal, but continues. Treatment plants are inadequate and water pipes

  7. Organ transplantation in Egypt.

    PubMed

    Paris, Wayne; Nour, Bakr

    2010-09-01

    Concern has increasingly been expressed about the growing number of reports of medical personnel participating in the transplantation of human organs or tissues taken from the bodies of executed prisoners, handicapped patients, or poor persons who have agreed to part with their organs for commercial purposes. Such behavior has been universally considered as ethically and morally reprehensible, yet in some parts of the world the practice continues to flourish. The concept of justice demands that every person have an equal right to life, and to protect this right, society has an obligation to ensure that every person has equal access to medical care. Regrettably, the Egyptian system does not legally recognize brain death and continues to allow the buying and selling of organs. For more than 30 years in Egypt, the ability to pay has determined who receives an organ and economic need has determined who will be the donor. As transplant professionals, it is important that we advocate on behalf of all patients, potential recipients, and donors and for those who are left out and not likely to receive a donor organ in an economically based system. Current issues associated with this debate are reviewed and recommendations about how to address them in Egypt are discussed. PMID:20929113

  8. Paleocene stratigraphy in Egypt

    NASA Astrophysics Data System (ADS)

    Farouk, Sherif

    2016-01-01

    The Egyptian Paleocene is widely distributed with vertical and lateral facies changes geographically separated and subject to different tectonic and sedimentary regimes. Five coeval facies associations of the Paleocene outcrops are identified and named from south to north: Garra El-Arbain, Nile Valley, Farafra, Sinai, and Southern Galala. Ten Paleocene third-order depositional sequences (Ds Da1 to Ds Th9) are tentatively distinguished in Egypt. These are bounded at their base and top by ten sequence boundaries (Eg.Da-1, Eg.Da-2, Eg.Da-3, Eg.Da-4, Eg.Da-5, Eg.Da-6, Eg.Se-7, Eg.Th.-8, Eg.Th.-9, and Eg.Eo-10). The relative ages and correlation of the Paleocene depositional sequences are based on planktonic foraminiferal biostratigraphy. Comparison of identified Paleocene sequences in and outside Egypt are referred to eustatic sea-level changes and partly to regional tectonics events, which have caused hiatuses of variable durations and different configurations of Paleocene sedimentary regimes from place to place.

  9. Transect workshop held in Egypt

    NASA Astrophysics Data System (ADS)

    Barazangi, Muawia

    A workshop on the progress of the Global Geoscience Transects (GGT) project in the Middle East and Africa (see maps) was held January 15-17 in Cairo, Egypt. (Transect plans in the region have been described in Eos, 69, p. 124). It was jointly organized and funded by the Egyptian National Committee of Geodesy and Geophysics and the International Lithosphere Program coordinating Committee CC-7 of GGT. A. Ashour of Cairo University, Egypt, chaired the workshop; the general secretary was S. Riad of Assiut University, Egypt, who was responsible for most of the organization, scheduling and implementation of the workshop.

  10. Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

    NASA Astrophysics Data System (ADS)

    Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

    2015-04-01

    The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary

  11. Desert Storm environmental effects

    NASA Astrophysics Data System (ADS)

    Kimball, E. W.

    It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide hot, dry climates.

  12. Animals of the Desert.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides background information and student activities on how desert animals have adapted to dryness and heat, how and when animals move on the desert, and nocturnal/diurnal animals. Each activity includes objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. Ready-to-copy pages are included for a…

  13. People and Deserts.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides: (1) background information on ways people affect deserts and ways deserts affect people; (2) student activities on this topic; and (3) ready-to-copy materials (culture match worksheet and causes worksheet). Each activity includes objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. (DH)

  14. Reclaiming freshwater sustainability in the Cadillac Desert

    PubMed Central

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H. W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%. PMID:21149727

  15. Reclaiming freshwater sustainability in the Cadillac Desert

    USGS Publications Warehouse

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H.W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

  16. Calcareous benthonic foraminifera across the Cretaceous/Paleocene transition of Gebel Um El-Ghanayem, Kharga Oasis, Egypt

    NASA Astrophysics Data System (ADS)

    Orabi, Orabi H.; Khalil, Hamza M.

    2014-08-01

    The studies of benthic calcareous foraminifera of the Maastrichtian-early Paleocene Dakhla Formation in Gebel Um El-Ghanayem (Western Desert, Egypt), improve reconstruction of depositional environments of these successions. In total, 68 taxa of benthic foraminifera were identified in the studied succession. The late Maastrichtian assemblages (Zone CF3) are dominated by calcareous foraminifera with tapered tests, this tapered taxon Loxostomum applinae, Lox. tegulatum various dentalinid taxa, and Buliminella cushmani dominate in CF3 Biozone. We thus interpret these faunas as being dominated by infaunal morphogroups, suggesting a moderately eutrophic environment. Danian assemblages are characterized by abundant epifaunal trochospiral species, such as Cibicidoides abudurbensis, Cibicidoides farafraensis, and Gyroidinoides girardanus. The infaunal morphogroups make up 25-47% of fauna in the Danian, in contrast to 62-76% in the Upper Maastrichtian. This dominance of the Danian benthic foraminiferal assemblages by epifaunal or mixed epifaunal/infaunal morphogroups suggests that the food supply to the benthos was less abundant than in the latest Cretaceous. The Cretaceous/Paleocene boundary (K/Pg) is within the upper unit of the Lower Kharga Member and marked by a hiatus in at least the top of CF3 Zone of the Upper Maastrichtian to the Lower Paleocene (base Plc Zone).

  17. Depositional environments and sequence architecture of the Raha and Abu Qada formations (Cenomanian-Turonian), west central Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Anan, Tarek I.; El-Shahat, Adam; Genedi, Adel; Grammer, Michael

    2013-06-01

    Cenomanian-Turonian deposits are important reservoirs for many oil fields in the Western Desert and the Gulf of Suez region of Egypt. Study of the Raha and Abu Qada formations (Cenomanian-Turonian), from five dip-oriented outcrop locations in west central Sinai; indicates deposition of a mixed siliciclastic-carbonate system on a ramp setting. The inner ramp facies (bivalve and benthonic foraminiferal wackestone) grades northward to the mid ramp facies (echinoderm calcisphere packstone, and oyster floatstone), and outer ramp facies (planktonic foraminiferal wackestone and calcisphere wackestone). The two studied formations comprise one second-order depositional sequence (duration of approximately 10 Million years). This large scale sequence includes four third-order depositional sequences, three of which are observed in the Raha Formation, with the other one recorded in the Abu Qada Formation. Because west central Sinai was tectonically stable during the Cenomanian and Turonian, the main factor controlling the lateral and vertical distribution of facies tracts is likely due to changes in the relative sea level. The Cenomanian-Turonian boundary event is known as the largest oceanic anoxic event during the Cretaceous. This global event has been documented in three of the studied sections. The recorded δ13C excursions range from +3.04‰ to +5.24‰. These high positive excursions in δ13C are associated with highly negative values of δ18O (values range from -6.01‰ to -1.38‰).

  18. New insights into microbially induced sedimentary structures in alkaline hypersaline El Beida Lake, Wadi El Natrun, Egypt

    NASA Astrophysics Data System (ADS)

    Taher, Amany G.; Abdel-Motelib, Ali

    2015-10-01

    Microbially induced sedimentary structures (MISS) were studied in detail in the alkaline hypersaline El Beida Lake of Wadi El Natrun in the western desert sector of Egypt, based on field observations and sampling performed in 2013 and 2014. Geomorphologically, the lake can be subdivided into three zones, each with characteristic sedimentary and biosedimentary structures. The marginal elevated zone that borders the lake is characterized by thick blocky crusts devoid of microbial mats. The middle-lower supratidal zone has luxuriant microbial mats associated with knotty surfaces, mat cracks and wrinkle structures. A zone of ephemeral shallow pools and channels is characterized by reticulate surfaces, pinnacle mats, sieve-like surfaces, gas domes and mat chips. In the microbial mats, authigenic minerals include thenardite Na2SO4, trona Na3(CO3)(HCO3)•2H2O and halite NaCl. Scanning electron microscopy (SEM) analyses revealed that the minerals are closely associated with the MISS, suggesting some influence of microorganisms on mineral precipitation. Complex interactions between regional hydrological cycles and diagenetic processes imply low preservation potential. MISS signatures of such saline lakes can serve as key analogues for interpreting the geologic record.

  19. Integrated geoelectrical survey for groundwater and shallow subsurface evaluation: case study at Siliyin spring, El-Fayoum, Egypt

    NASA Astrophysics Data System (ADS)

    Metwaly, Mohamed; El-Qady, Gad; Massoud, Usama; El-Kenawy, Abeer; Matsushima, Jun; Al-Arifi, Nasser

    2010-09-01

    Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.

  20. Negev: Land, Water, and Life in a Desert Environment

    NASA Astrophysics Data System (ADS)

    Back, William

    In view of the continuing increased concern about the extreme fragility of deserts and desert margins, Negev provides a timely discussion of land-use practices compatible with the often conflicting goals of preservation and development. The success o f agricultural and hydrologic experiments in the Negev desert of Israel offers hope to the large percentage of the world's population that lives with an unacceptably low quality of life in desert margins. Deserts are the one remaining type of open space that, with proper use, has the potential for alleviating the misery often associated with expanding population.In addition to the science in the book, the author repeatedly reinforces the concept that “western civilization is inextricably bound to the Negev and its environs, from which it has drawn, via its desert-born religions—Judasium, Christianity, and Islam—many of the mores and concepts, and much of the imagery and love of the desert, including man's relation to nature and to ‘God’.” Deserts often are erroneously perceived to be areas of no water: In reality, these are areas in which a little rainfall occurs sporadically and unpredictably over time. This meager water supply can be meticulously garnered to produce nutritious crops and forage.

  1. Environmental health in Egypt.

    PubMed

    Anwar, Wagida A

    2003-08-01

    Egypt shares most of the environmental problems of developing countries. One of the most important health and environmental problems is air pollution resulting from using fuel, burning operations, and the increase of automobile exhaust in cities. Moreover, the deficiency of efficient sanitation services and water pollution caused by the breaking down of old and consumed water networks, as well as the various problems in construction, designing and maintenance of sewage system resulted in the appearance and prevalence of communicable and non-communicable diseases. There are several examples of exposure to chemical genotoxicants, and lifestyle exposures in the population, which create unique combinations of environmental risk factors for diseases such as cancer. Environmental factors may interact with infection and lead to enhancement of carcinogenicity processes. Currently, there is a growing interest in environmental mutagenicity and carcinogenicity research. The use of different biomarkers and genetic susceptibility testing can contribute effectively to risk assessment. The Government of Egypt recognizes and deals seriously with these problems. The State Ministry of Environment has initiated new policies that include risk minimization, law enforcement, treatment of pollution at source, mitigation procedures and inter-sectorial collaboration. The Ministry of Health and Population recognized the link between economic development, environment and health. It elaborated a national environment health strategy in accordance with the format of the regional and global environmental health policy. This strategy identified priority areas, which requires further action to be taken and to be implemented. Environmental health was included as one of the four main objectives of the strategic Healthy Egyptians 2010 Initiative. Specific objectives and plans for the initiative are presented. PMID:12971689

  2. Are Food Deserts Also Play Deserts?

    PubMed

    Cohen, Deborah A; Hunter, Gerald; Williamson, Stephanie; Dubowitz, Tamara

    2016-04-01

    Although food deserts are areas that lack easy access to food outlets and considered a barrier to a healthy diet and a healthy weight among residents, food deserts typically comprise older urban areas which may have many parks and street configurations that could facilitate more physical activity. However, other conditions may limit the use of available facilities in these areas. This paper assesses the use of parks in two Pittsburgh food desert neighborhoods by using systematic observation. We found that while the local parks were accessible, they were largely underutilized. We surveyed local residents and found that only a minority considered the parks unsafe for use during the day, but a substantial proportion suffered from health limitations that interfered with physical activity. Residents also felt that parks lacked programming and other amenities that could potentially draw more park users. Parks programming and equipment in food desert areas should be addressed to account for local preferences and adjusted to meet the needs and limitations of local residents, especially seniors. PMID:27033184

  3. The effect of drought on four plant communities in the northern Mojave Desert

    SciTech Connect

    Schultz, B.W.; Ostler, W.K.

    1993-12-31

    Desert plant communities contain many perennial plant species that are well adapted to arid environments; therefore, one would intuitively believe that perennial desert species readily survive drought conditions. Abundant research on plant-soil-water relationships in North American deserts has shown that many species can maintain water uptake and growth when the soil-water potential is low. Little research, however, has focused on how prolonged drought conditions affect plant species in vegetation associations in desert ecosystems. A prolonged and widespread drought occurred in much of the western United States, including the Northern Mojave Desert, from 1987 through 1991. During this drought period vegetation characterization studies, initiated in 1990, by the US Department of Energy (DOE) at Yucca Mountain, Nevada, allowed EG and G Energy Measurements to collect data that could be used to infer how both desert vegetation associations and desert plant species reacted to a prolonged drought. This paper presents the preliminary results.

  4. The Nile floodplain, hydroclimatic variability, and its relation with cultural dynamics in ancient Thebes (Luxor, Egypt)

    NASA Astrophysics Data System (ADS)

    Toonen, Willem H. J.; Graham, Angus; Pennington, Ben; Hunter, Morag; Strutt, Kris; Barker, Dominic; Masson, Aurelia; Emery, Virginia

    2016-04-01

    The western bank of the river Nile in the Luxor region (Egypt) separates New Kingdom divine temple complexes in the central axis of the river valley from contemporaneous sites on the desert edge and limestone plateau. The intermediate Nile floodplain features relatively few known archaeological sites, but played an important role in the ancient ritual landscape by connecting the focal region of the living (floodplain) with that of the dead (desert). All Royal Funerary Temple Complexes of the New Kingdom period (1539-1077 BCE), which played a central role in the cosmogonical landscape, are positioned within a confined 3.5 km long strip of land on the western edge of the present floodplain. This preferential location, together with contemporary textual sources and tomb scenes suggesting the nearby presence of canals, have led to the hypothesis that natural and human-made waterways may have once connected the main channel of the Nile with the desert edge. Until the present research took place, no detailed study of pre-existing channel networks existed in the region, leaving a gap in current knowledge on the configuration and use of the ancient floodplain. This study presents the results of a multi-disciplinary study aimed at mapping and dating ancient waterways in the Theban region and aims to find evidence for the natural or human origin of such channels. Boreholes and Electric Resistivity Tomography (ERT) were carried out along a transect that connects the edge of the Holocene floodplain with the current position of the river Nile. Satellite imagery and textual sources were also used to augment the fieldwork. The data indicate the presence of an infilled abandoned channel of the Nile in the western distal part of the current floodplain, adjoining the Funerary Temple complexes. Over 2100 ceramic fragments were analysed from the sedimentary infilling of the silted-up river course, dating it to the end of the New Kingdom, and indicating that the channel and temples

  5. What is Desert RATS?

    NASA Video Gallery

    The mission manager and test coordinators for the 2011 mission explain why Desert RATS was started 14 years ago, questions being studied in this year's activities, technologies being tested and the...

  6. The use of multifrequency and polarimetric SIR-C/X-SAR data in geologic studies of Bir Safsaf, Egypt

    USGS Publications Warehouse

    Schaber, G.G.; McCauley, J.F.; Breed, C.S.

    1997-01-01

    Bir Safsaf, within the hyperarid 'core' of the Sahara in the Western Desert of Egypt, was recognized following the SIR-A and SIR-B missions in the 1980s as one of the key localities in northeast Africa, where penetration of dry sand by radar signals delineates previously unknown, sand-buried paleodrainage valleys ('radar-rivers') of middle Tertiary to Quaternary age. The Bir Safsaf area was targeted as a focal point for further research in sand penetration and geologic mapping using the multifrequency and polarimetric SIR-C/X-SAR sensors. Analysis of the SIR-C/X-SAR data from Bir Safsaf provides important new information on the roles of multiple SAR frequency and polarimetry in portraying specific types of geologic units, materials, and structures mostly hidden from view on the ground and on Landsat TM images by a relatively thin, but extensive blanket of blow sand. Basement rock units (granitoids and gneisses) and the fractures associated with them at Bir Safsaf are shown here for the first time to be clearly delineated using C- and L-band SAR images. The detectability of most geologic features is dependent primarily on radar frequency, as shown for wind erosion patterns in bedrock at X-band (3 cm wavelength), and for geologic units and sand and clay-filled fractures in weathered crystal-line basement rocks at C-band (6 cm) and L-band (24 cm). By contrast, Quaternary paleodrainage channels are detectable at all three radar frequencies owing, among other things, to an usually thin cover of blow sand. The SIR-C/X-SAR data investigated to date enable us to make specific recommendations about the utility of certain radar sensor configurations for geologic and paleoenvironmental reconnaissance in desert regions.Analysis of the shuttle imaging radar-C/X-synthetic aperture radar (SIR-C/X-SAR) data from Bir Safsaf provides important new information on the roles of multiple SAR frequency and polarimetry in portraying specific types of geologic units, materials, and

  7. New Paleocene Sepiid Coleoids (Cephalopoda) from Egypt: Evolutionary Significance and Origin of the Sepiid ‘Rostrum’

    PubMed Central

    Košťák, Martin; Jagt, John W. M.; Speijer, Robert P.; Stassen, Peter; Steurbaut, Etienne

    2013-01-01

    New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a ‘rostrum-like’ prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or ‘rostrum-like’ structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian–Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America. PMID:24348918

  8. DISTRIBUTIONAL CHANGES AND POPULATION STATUS FOR AMPHIBIANS IN THE EASTERN MOJAVE DESERT

    EPA Science Inventory

    A number of amphibian species historically inhabited sparsely distributed wetlands in the Mojave Desert of western North America, habitats that have been dramatically altered or eliminated as a result of human activities. The population status and distributional changes for amphi...

  9. Range and habitats of the desert tortoise

    USGS Publications Warehouse

    Germano, D.J.; Bury, R.B.; Esque, T.C.; Fritts, T.H.

    1994-01-01

    We determined the current range of the desert tortoise (Gopherus agassizii) based on the available latest data from government agencies, the literature, and our experience. We developed the first detailed range map of this species and summarized information about habitat preferences. New records of occurrences were incorporated, and some peripheral localities of questionable authenticity were deleted. The distribution oCG. agassizii covers the broadest range of latitude, climatic regimes, habitats, and biotic regions of any North American tortoise. The northern portion ofits range is in the Mojave Desert of sDuth"eastern California, southern Nevada, southwestern Utah, and northwestern Arizona. The central portion of the range consists of several subdivisions of the Sonaran Desert in southeastern California, western and southern Arizona, and western Sonora, Mexico. The southern edge of its range is in the semitropical Sinaloan thornscrub and Sinaloan deciduous forest of eastern Sonora and northern Sinaloa, Mexico. This species has marked geogi-aphic differences but seems to construct burrows throughout its range.

  10. Sonoran Desert: Fragile Land of Extremes

    USGS Publications Warehouse

    Produced and Directed by Wessells, Stephen

    2003-01-01

    'Sonoran Desert: Fragile Land of Extremes' shows how biologists with the U.S. Geological Survey work with other scientists in an effort to better understand native plants and animals such as desert tortoises, saguaro cacti, and Gila monsters. Much of the program was shot in and around Saguaro National Park near Tucson, Arizona. Genetic detective work, using DNA, focuses on understanding the lives of tortoises. Studies of saguaros over many decades clarify how these amazing plants reproduce and thrive in the desert. Threats from fire, diseases in tortoises, and a growing human population motivate the scientists. Their work to identify how these organisms live and survive is a crucial step for the sound management of biological resources on public lands. This 28-minute program, USGS Open-File Report 03-305, was shot entirely in high definition video and produced by the USGS Western Ecological Research Center and Southwest Biological Science Center; produced and directed by Stephen Wessells, Western Region Office of Communications.

  11. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  12. Eyewitness introduction to Egypt: "The gift of the Nile".

    PubMed

    Brown, Geraldine

    2009-01-01

    Northeastern corner of Africa, lying at the crossroads between the two continents of Europe and Asia (in the Sinai Peninsula), while bordering Libya, Sudan, Israel and the Red Sea. Egypt is the most ancient tourist country in the world. Several health fact-finding missions in the last few years were made to this small country that is frequently defined by the Valley of the Nile. With the spreading deserts on either side, or a very rich heritage of ancient relics, these scenic vistas are without equal elsewhere in the world. Although there are significant cultural differences among the population, Egypt has a long history of ethnic and religious compassion. Among the many rarities, main tourist attractions include the three great Pyramids of Giza and the Sphinx, amazing ancient wonders of the world. These fact-finding missions included how health and medical care are defined, how people and culture are intertwined with its physical features, land use, and the economy and its resources. PMID:19927898

  13. [Comparative studies of climatic factors effecting the performance of cattle in different climatic zones of Egypt].

    PubMed

    Legel, S; Touny, S M

    1982-01-01

    In continuation of previous analogous studies on climatic factors influencing the performance of cattle in Northern Egypt (climate types III4a/IV: etesian climate of the Mediterranean type) the present investigation deals with the temperature and humidity for Southern Egypt (climate type III1; arid, subtropical desert climate) and classifies them according to the physiological tolerability ranges set up for cattle. In Northern Egypt (Maryut) 23.8% of the temperatures were beyond the optimum and physiologically still tolerable range (0 to 24 degrees C) and were thus in the intolerable range; 45.8% were within the optimum tolerability range. In Southern Egypt (El Menia) 46.7% were within the intolerable range and only 25.7% in the optimum range (5 to 18 degrees C). The relative humidity values had 21.9% within the optimum range and 63.9% in the intolerable range in the North; in the South 22.9% were within the optimum and 55.5% in the intolerable range. PMID:7171369

  14. ASTER View of Sharm El Sheik, Egypt

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Red Sea golf resort in Sharm El Sheik, Egypt, where President Clinton met with Israeli Prime Minister Ehud Barak and Palestinian Authority President Yasser Arafat, stands out against the desert landscape in this image acquired on August 25, 2000.

    This image of the southern tip of the Sinai Peninsula shows an area about 30 by 40 kilometers (19 by 25 miles) in the visible and near infrared wavelength region. Vegetation appears in red. The blue areas in the water at the top and bottom of the image are coral reefs. The airport is visible just to the north of the golf resort.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology

  15. The application of petrophysics to resolve fluid flow units and reservoir quality in the Upper Cretaceous Formations: Abu Sennan oil field, Egypt

    NASA Astrophysics Data System (ADS)

    Lala, Amir Maher Sayed; El-sayed, Nahla Abd El-Aziz

    2015-02-01

    Petrophysical flow unit concept can be used to resolve some of the key challenges faced in the characterization of hydrocarbon reservoirs. The present study deals with petrophysical evaluation of some physical properties of the Upper Cretaceous rock samples obtained from the Abu-Roash and the Bahariya Formations at southwest of Sennan oil field in the Western Desert of Egypt. The aim of this study was achieved through carrying out some petrophysical measurements of porosity, bulk density, permeability, mean hydraulic radius (Rh), irreducible water saturation, and radius of pore throat at mercury saturation of 35% in order to determine reservoir characteristics. In this study, the relationships obtained between the measured petrophysical properties such as porosity, permeability and pore throat flow unit types were established for 53 sandstone core samples obtained from two different stratigraphic units. Flow zone indicator (FZI) has been calculated to quantify the flow character of the Abu-Roash and Bahariya reservoir rocks based on empirically derived equations of robust correlation coefficients. The correlations among porosity, permeability, bulk density, mean hydraulic radius and pore throat flow properties reflect the most important reservoir behavior characteristics. The calculated multiple regression models indicate close correlation among petrophysical properties and Rh and R35%. The obtained models are able to predict Rh and R35% by using porosity and permeability, to map reservoir performance and predict the location of stratigraphic traps.

  16. Analysis of groundwater flow in arid areas with limited hydrogeological data using the Grey Model: a case study of the Nubian Sandstone, Kharga Oasis, Egypt

    NASA Astrophysics Data System (ADS)

    Mahmod, Wael Elham; Watanabe, Kunio; Zahr-Eldeen, Ashraf A.

    2013-08-01

    Management of groundwater resources can be enhanced by using numerical models to improve development strategies. However, the lack of basic data often limits the implementation of these models. The Kharga Oasis in the western desert of Egypt is an arid area that mainly depends on groundwater from the Nubian Sandstone Aquifer System (NSAS), for which the hydrogeological data needed for groundwater simulation are lacking, thereby introducing a problem for model calibration and validation. The Grey Model (GM) was adopted to analyze groundwater flow. This model combines a finite element method (FEM) with a linear regression model to try to obtain the best-fit piezometric-level trends compared to observations. The GM simulation results clearly show that the future water table in the northeastern part of the study area will face a severe drawdown compared with that in the southwestern part and that the hydraulic head difference between these parts will reach 140 m by 2060. Given the uncertainty and limitation of available data, the GM produced more realistic results compared with those obtained from a FEM alone. The GM could be applied to other cases with similar data limitations.

  17. Spatially variable sedimentary responses to orbitally driven pluvial climate during Marine Oxygen Isotope Stage 5.1, Dakhla Oasis region, Egypt

    NASA Astrophysics Data System (ADS)

    Brookes, Ian A.

    2010-09-01

    Pleistocene basinal sediments (PBS) in the Dakhla region of Egypt's hyperarid Western Desert comprise four facies: (A) fluvio-lacustrine, (B) mixed lacustrine/pluvio-eolian, (C) pluvio-eolian, and (D) mixed eolian/pluvio-eolian. Contiguity of basins containing each facies, and their stratigraphic position between two bajada gravel formations, P/B-II and P/B-III, confirm their equivalence. Facies A and B, with lacustrine components, are attributed to orbitally forced poleward incursion of the Intertropical Convergence Zone (ITCZ), resulting in increased summer insolation/temperature/precipitation. Facies C and D, comprising pluvio-eolian and eolian sediments, reflect geologic/topographic influences overprinted on regional 'pluvial' conditions, eliminating lacustrine response. A Th/U age of ˜ 62 ka on lacustrine marl within Facies B is minimal, and an OSL age of 110 ± 18 ka on sediments immediately below Facies B is maximal. Since bajada gravels P/B-III are the youngest Pleistocene formation, they must represent the final strong incursion of the ITCZ into the Dakhla region at MIS 5.1, ˜ 80 ka. Because PBS Facies A pass rapidly up into P/B-III bajada gravels, PBS are assigned to the rising limb of the MIS 5.1 insolation/temperature/precipitation curve, slightly younger than 80 ka.

  18. Tectonic framework of northeast Egypt and its bearing on hydrocarbon exploration

    SciTech Connect

    Khalil, M.; Moustafa, A.R.

    1995-08-01

    Detailed structural study of northern and central Sinai, the northern Eastern Desert, and the northern Gulf of Suez clarified the tectonic framework of northeast Egypt. This framework is related to the movements between the African Plate and the Eurasian and Arabian Plates. Late Cretaceous folding and thrusting in response to oblique convergence between the African and Eurasian Plates formed NE-ENE oriented, doubly plunging, en echelon folds of the northern Egypt fold belt. This fold belt is well exposed in northern Sinai and a few other places but is concealed under younger sediments in the other parts of northern Egypt. Younger folding of local importance is related to dextral slip on the Themed Fault (Central Sinai) in post Middle Eocene-pre Miocene time. Early Miocene rifting of the Afro-Arabian Plate led to the opening of the Suez rift and deposition of significant syn-rift facies. Half grabens and tilted fault blocks dominate the rift. Slightly tilted fault blocks characterize the competent Middle Eocene limestones of the Eastern Desert south of the Cairo-Suez road but north of this road, Middle Eocene rocks are locally dragged on nearby E-W and NW-SE oriented faults forming fault-drag folds. Ductile Upper Eocene and Miocene rocks are also folded about gentle NW-SE oriented doubly plunging folds. The different stages of tectonic activity in northern Egypt contributed to the development of different types of structural traps as well as different source, reservoir, and cap rocks. The sedimentary history of the region indicates well developed marine sediments of Jurassic, Cretaceous, Eocene, and Miocene ages. Basin development in structurally low areas provided good sites for hydrocarbon generation and maturation.

  19. Palynology and Stratigraphy of the Nubian Sandstone in Libya and Comparison with Egypt

    NASA Astrophysics Data System (ADS)

    Tekbali, Ali; Hlal, Osama

    2013-04-01

    The so-called "Nubian Sandstone" outcrops along a wide area from Algeria to the Red Sea, forming two regressive phases. The lower phase is represented in Egypt by the Basal Clastic Unit, the Desert Rose Unit, the Abu Ballas Formation and the Matruh Shale. In Libya it is represented by the Mesak Sandstone, Sarir Sandstone, Cabao Sandstone and Kiklah Formation. In both countries, these successions are covered by a carbonate sequence, resulting from the Tethyan transgression during the Cenomanian. In Egypt however, the upper regressive phase is represented by the Taref Sandstone which was deposited during a brief period of active progradation, following the Tethyan incursion. This is not observed in Libya. Comparison of palynological studies in Libya with those documented by several authors in Egypt reveals that the "Nubian" facies in Libya were deposited before equivalent facies in Egypt. The Basal Clastic Unit, dated as Hautrauvian-Barremian, may be equivalent, at least to a part of the Neocomian Cabao Sandstone in NW Libya. Jarmah Member of the Mesak Formation in Libya was dated as Berriasian on the basis of Pilosisporites and Trilobosporites. This makes it older than any "Nubian" unit in Egypt. The Matruh Shale was assigned to the Aptian on the basis of Tricolpites, and the Abu Balls Formation 34 as Aptian-Albian on the basis of Tricolpites and Rousisporites radiatus. Whereas, there is no equivalent to the Aptian in NW Libya, the Aptian-Albian of Egypt is similar to Zone 1 of the Kiklah Formation and As Sarir Sandstone, which were dated as early Albian on the basis of Afropollis spp., and Perotriletes pannuceus, an Albian element not recorded in Egypt. The Plant Beds in southwestern Egypt were dated as Cenomanian on the basis of advanced angiosperm pollen. In Libya, equivalent bodies were considered Vraconian, representing the uppermost Albian, because it lacks Cenomanian pollen (e.g. Tricolpites mutabilis). Comparison of local sea-level changes with global sea

  20. Sounds of the Desert.

    ERIC Educational Resources Information Center

    McCullough-Brabson, Ellen; Achilles, Elayne; Ashcraft, Joan

    1997-01-01

    Discusses the program called "Sounds of the Desert" that celebrates the Southwest indigenous culture and focuses on understanding music in relation to history and culture. Emphasizes the study of Mariachi music that is being taught alongside band, orchestra, and chorus from the third grade to senior high in many Tucson (Arizona) schools. (CMK)

  1. How desert varnish forms?

    NASA Astrophysics Data System (ADS)

    Perry, Randall S.; Kolb, Vera M.; Lynne, Bridget Y.; Sephton, Mark A.; Mcloughlin, Nicola; Engel, Michael H.; Olendzenski, Lorraine; Brasier, Martin; Staley, James T., Jr.

    2005-09-01

    Desert varnish is a black, manganese-rich rock coating that is widespread on Earth. The mechanism underlying its formation, however, has remained unresolved. We present here new data and an associated model for how desert varnish forms, which substantively challenges previously accepted models. We tested both inorganic processes (e.g. clays and oxides cementing coatings) and microbial methods of formation. Techniques used in this preliminary study include SEM-EDAX with backscatter, HRTEM of focused ion beam prepared (FIB) wafers and several other methods including XRPD, Raman spectroscopy, XPS and Tof-SIMS. The only hypothesis capable of explaining a high water content, the presence of organic compounds, an amorphous silica phase (opal-A) and lesser quantities of clays than previously reported, is a mechanism involving the mobilization and redistribution of silica. The discovery of silica in desert varnish suggests labile organics are preserved by interaction with condensing silicic acid. Organisms are not needed for desert varnish formation but Bacteria, Archaea, Eukarya, and other organic compounds are passively incorporated and preserved as organominerals. The rock coatings thus provide useful records of past environments on Earth and possibly other planets. Additionally this model also helps to explain the origin of key varnish and rock glaze features, including their hardness, the nature of the "glue" that binds heterogeneous components together, its layered botryoidal morphology, and its slow rate of formation.

  2. Plants of the Desert.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides background information and student activities on plants of the desert, including various adaptations for life with limited water supplies. Each activity includes objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. A ready-to-copy student worksheet is included. (DH)

  3. Mojave Desert Diary

    ERIC Educational Resources Information Center

    Breed, Allen F.

    1974-01-01

    This is an account of a trip to the Mojave Desert sponsored by the California Youth Authority's Community Parole Center for wards who are selected on the basis of their potential for growth and their ability to make a connection between what they do in the wilderness and what they do on the streets. (PD)

  4. A study of Desert Dermatoses in the Thar Desert Region

    PubMed Central

    Chatterjee, Manas; Vasudevan, Biju

    2015-01-01

    Introduction: Desert dermatology describes the cutaneous changes and the diseases affecting those living in the desert. Diurnal variation in temperature is high and is characteristic of the deserts. The lack of water affects daily activities and impacts dermatological conditions. Adaptation to the desert is therefore important to survival. This original article focuses on dermatoses occurring in a population in the Thar desert of India, predominantly located in Rajasthan. Materials and Methods: This is a descriptive study involving various dermatoses seen in patients residing in the Thar desert region over a duration of 3 years. Results: Infections were the most common condition seen among this population and among them fungal infections were the most common. The high incidence of these infections would be accounted for by the poor hygienic conditions due to lack of bathing facilities due to scarcity of water and the consequent sweat retention and overgrowth of cutaneous infective organisms. Pigmentary disorders, photodermatoses, leishmaniasis and skin tumors were found to be more prevalent in this region. Desert sweat dermatitis was another specific condition found to have an increased incidence. Conclusion: The environment of the desert provides for a wide variety of dermatoses that can result in these regions with few of these dermatoses found in much higher incidence than in other regions. The concept of desert dermatology needs to be understood in more details to provide better care to those suffering from desert dermatoses and this article is a step forward in this regard. PMID:25657392

  5. Regional geothermal exploration in Egypt

    NASA Technical Reports Server (NTRS)

    Morgan, P.; Boulos, F. K.; Swanberg, C. A.

    1983-01-01

    A study is presented of the evaluation of the potential geothermal resources of Egypt using a thermal gradient/heat flow technique and a groundwater temperature/chemistry technique. Existing oil well bottom-hole temperature data, as well as subsurface temperature measurements in existing boreholes, were employed for the thermal gradient/heat flow investigation before special thermal gradient holes were drilled. The geographic range of the direct subsurface thermal measurements was extended by employing groundwater temperature and chemistry data. Results show the presence of a regional thermal high along the eastern margin of Egypt with a local thermal anomaly in this zone. It is suggested that the sandstones of the Nubian Formation may be a suitable reservoir for geothermal fluids. These findings indicate that temperatures of 150 C or higher may be found in this reservoir in the Gulf of Suez and Red Sea coastal zones where it lies at a depth of 4 km and deeper.

  6. Epidemic of mesothelioma in Egypt.

    PubMed

    Gaafar, R M; Eldin, N H Aly

    2005-07-01

    Asbestos has been recognized in Egypt since a long time as ancient Egyptians were using it in mummification. Mesothelioma in Egypt is mainly attributed to environmental origin with a high incidence of women and young adults affected. The incidence of mesothelioma is rising in Egypt. Epidemiological data for 635 malignant mesothelioma (MM) patients over 4 years in the third Millennium were collected from the National Cancer Institute (NCI), Cairo University and Abbassia Chest hospital. This number is more than four times the number diagnosed in the previous 11 years at NCI. A clinicopathological study was done for 100 malignant pleural mesothelioma (MPM) patients and showed that asbestos exposure and SV40 positivity were evident in 67% and 60% of cases, respectively. The median survival was 14.3 months and the 1 and 2 year survival rates were 60% and 27%, respectively. Evaluation of p53 and pRb immunohistochemically showed that pRb alteration was related to poor survival. Other biological prognostic factors such as EGFR, HER-2, glutathione S transferase (GST) and MDR were evaluated in 50 cases. Overexpression of EGFR was correlated with lack of clinical benefit and poor survival. GST potentiated the effect of EGFR on survival. The use of EGFR inhibitors may have a role in the treatment of MM. Asbestos in Cairo is a silent killer and measures toward eliminating it entirely or at least strictly controlling human contact with this dangerous carcinogen have to be taken in order to combat the coming epidemic of mesothelioma in Egypt. PMID:15950794

  7. Wind modeling of Chihuahuan Desert dust outbreaks

    NASA Astrophysics Data System (ADS)

    Rivera Rivera, Nancy I.; Gill, Thomas E.; Gebhart, Kristi A.; Hand, Jennifer L.; Bleiweiss, Max P.; Fitzgerald, Rosa M.

    The Chihuahuan Desert region of North America is a significant source of mineral aerosols in the Western Hemisphere, and Chihuahuan Desert dust storms frequently impact the Paso del Norte (El Paso, USA/Ciudad Juarez, Mexico) metropolitan area. A statistical analysis of HYSPLIT back trajectory residence times evaluated airflow into El Paso on all days and on days with synoptic (non-convective) dust events in 2001-2005. The incremental probability—a measure of the areas most likely to have been traversed by air masses arriving at El Paso during dusty days—was only strongly positively associated with the region west-southwest of the city, a zone of known dust source areas. Focused case studies were made of major dust events on 15 April and 15 December 2003. Trajectories approached the surface and MM5 (NCAR/Penn State Mesoscale Model) wind speeds increased at locations consistent with dust sources observed in satellite imagery on those dates. Back trajectory and model analyses suggested that surface cyclones adjacent to the Chihuahuan Desert were associated with the extreme dust events, consistent with previous studies of dust storms in the Southern High Plains to the northeast. The recognition of these meteorological patterns serves as a forecast aid for prediction of dust events likely to impact the Paso del Norte.

  8. Experience with NORPLANT in Egypt.

    PubMed

    Shaaban, M M

    1993-04-01

    Experience with the contraceptive NORPLANT in Egypt dates back to early 1980 when the first multicentre trial was initiated. To date, more than 3000 women have received this contraceptive at the Assiut University Family Clinic alone. Analysis of the overall experience in this clinic has indicated a 5-year cumulative continuation rate of 51 and a pregnancy rate of 1.8 per 100 women. Clinical pharmacology studies pertaining to the safety of NORPLANT in our community have indicated no deleterious effect on the lipid profile, liver functions and blood coagulation system. Two studies conducted in Egypt have indicated that the initiation of NORPLANT use shortly after delivery does not have any unfavourable effect on lactational performance, or on physical or psychomotor development of the breast-fed infants. This is particularly important in Arab and Moslem cultures where prolonged breast-feeding is emphasized. A study utilizing focus-group discussion to assess users' attitudes to NORPLANT has indicated the need to improve the informational/educational package given in the service by emphasizing certain cultural considerations. On the whole, this first implant method has proven to be safe and acceptable in Egypt, where there is a special need for long-term methods for contraception, particularly as sterilization is not socially acceptable. PMID:8489755

  9. Orthopedic surgery in ancient Egypt

    PubMed Central

    Blomstedt, Patric

    2014-01-01

    Background — Ancient Egypt might be considered the cradle of medicine. The modern literature is, however, sometimes rather too enthusiastic regarding the procedures that are attributed an Egyptian origin. I briefly present and analyze the claims regarding orthopedic surgery in Egypt, what was actually done by the Egyptians, and what may have been incorrectly ascribed to them. Methods — I reviewed the original sources and also the modern literature regarding surgery in ancient Egypt, concentrating especially on orthopedic surgery. Results — As is well known, both literary sources and the archaeological/osteological material bear witness to treatment of various fractures. The Egyptian painting, often claimed to depict the reduction of a dislocated shoulder according to Kocher’s method, is, however, open to interpretation. Therapeutic amputations are never depicted or mentioned in the literary sources, while the specimens suggested to demonstrate such amputations are not convincing. Interpretation — The ancient Egyptians certainly treated fractures of various kinds, and with varying degrees of success. Concerning the reductions of dislocated joints and therapeutic amputations, there is no clear evidence for the existence of such procedures. It would, however, be surprising if dislocations were not treated, even though they have not left traces in the surviving sources. Concerning amputations, the general level of Egyptian surgery makes it unlikely that limb amputations were done, even if they may possibly have been performed under extraordinary circumstances. PMID:25140982

  10. Astronomy Education Challenges in Egypt

    NASA Astrophysics Data System (ADS)

    El Fady Beshara Morcos, Abd

    2015-08-01

    One of the major challenges in Egypt is the quality of education. Egypt has made significant progress towards achieving the Education for All and the Millennium Development Goals (MDGs). Many associations and committees as education reform program and education support programs did high efforts in supporting scientific thinking through the scientific clubs. The current state of astronomical education in Egypt has been developed. Astronomy became a part in both science and geography courses of primary, preparatory and secondary stages. Nowadays the Egyptian National Committee for Astronomy, put on its shoulders the responsibility of revising of astronomy parts in the education courses, beside preparation of some training programs for teachers of different stages of educations, in collaboration with ministry of education. General lectures program has been prepared and started in public places , schools and universities. Many TV and Radio programs aiming to spread astronomical culture were presented. In the university stage new astronomy departments are established and astrophysics courses are imbedded in physics courses even in some private universities.

  11. Snow, the Great River, and the Desert

    NASA Astrophysics Data System (ADS)

    Rango, A.

    2005-12-01

    While many major rivers around the world originate from alpine snowpacks in mountain regions, some experience the extreme contrast of flowing through harsh desert environments downriver. One such stream is the Rio Grande which rises in the San Juan and the Sangre de Christo mountains of southern Colorado and northern New Mexico. Eventually, the snow fed Rio Grande flows through North America's largest desert, the Chihuahuan Desert in New Mexico, Texas, and Mexico, and simultaneously becomes part of the border between the United States and Mexico. As is often true, urban areas develop along the river corridors rather than in more inaccessible mountain regions. This demographic preference tends to isolate the vast majority of population in the Rio Grande, who are dependent on water for their livelihoods, from the mountain snowpacks where the flow is generated. Ironically then, snow is seldom viewed as the source of the much needed water flowing through the desert by the majority of the basin's population. In arid regions of the western U.S., water demand far exceeds the water supply, and water use is apportioned under the doctrine of prior appropriation with the oldest right getting the first use of water. The increasing population in urban areas does not usually have a right to use the water flowing through the desert unless water rights have been purchased by municipalities from the major category of water user in these basins, namely, irrigated agriculture. In the entire Rio Grande basin, irrigation makes up 80% of the consumptive use of water. Additionally, basin compacts and international treaties apportion water between states and countries. Because these formal agreements were based on above average runoff years, there is little flexibility in changing the use of water, particularly in dry to normal runoff years. Most of the older water rights in the Rio Grande, especially the upper basin, are supplied by snowmelt. This leaves the lower basin to depend upon

  12. Metal and fluid sources in a potential world-class gold deposit: El-Sid mine, Egypt

    NASA Astrophysics Data System (ADS)

    Helmy, Hassan; Zoheir, Basem

    2015-04-01

    Lode gold mineralization at the El-Sid mine area is associated with the ca. 600 Ma Fawakhir granite intrusion, which cuts the ~737 Ma ophiolite nappes in the Central Eastern Desert of Egypt. The mineralized quartz veins are hosted by ~E- and NE-trending fault/fracture sets cutting the western boundary of the intrusion and sheared ophiolites. The results of electron microprobe analyses of gold-associated hydrothermal sulfide and silicate minerals suggest that Au was mobilized alongside Ni, Co, Cr and As from the adjacent ophiolitic serpentinite. After granite emplacement, hydrothermal fluids interacted with the sheared serpentinite, leaching metals and re-depositing them in the faults/fractures and adjacent wall rock in a cyclic process. Low-salinity aqueous-carbonic fluids with significant quantities of volatile species (CO2, CH4, and N2 ± H2S) leached and transported Au from deep to shallow crustal levels. Carbon dioxide had a buffering effect on the Au-bearing hydrothermal solution, maintaining its pH within a narrow near-neutral range, where elevated gold concentration was transported by complexation with reduced magmatic sulfur in a reducing environment. Gold deposition along fault/fracture conduits in the Fawakhir granite and adjacent serpentinite resulted from interplay of pressure drop, fluctuations in oxygen and sulfur fugacities, and exsolution of the volatile phases. Infiltration of meteoric water may have contributed to the formation of the late stage gold-sulfide mineralization that formed at shallower levels during terrane uplift. Sulfidation of the Fe-rich magmatic minerals was, on the other hand, the overriding process in the wall rock as evidenced by abundant disseminated sulfides with gold inclusions. Considering the structural control by regional shear zones (fluid conduits) and the voluminous granitic and ophiolitic rocks (metal sources), a high tonnage gold deposit amenable to open pit mining at the El-Sid mine area is very likely.

  13. Hydrogeochemical evolution of inland lakes’ water: A study of major element geochemistry in the Wadi El Raiyan depression, Egypt

    PubMed Central

    Mohamed, Essam A.; El-Kammar, Ahmed M.; Yehia, Mohamed M.; Abu Salem, Hend S.

    2015-01-01

    Wadi El Raiyan is a great depression located southwest of Cairo in the Western Desert of Egypt. Lake Qarun, located north of the study area, is a closed basin with a high evaporation rate. The source of water in the lake is agricultural and municipal drainage from the El Faiyum province. In 1973, Wadi El Raiyan was connected with the agricultural wastewater drainage system of the Faiyum province and received water that exceeded the capacity of Lake Qarun. Two hydrogeological regimes have been established in the area: (i) higher cultivated land and (ii) lower Wadi El Raiyan depression lakes. The agricultural drainage water of the cultivated land has been collected in one main drain (El Wadi Drain) and directed toward the Wadi El Raiyan depression, forming two lakes at different elevations (upper and lower). In the summer of 2012, the major chemical components were studied using data from 36 stations distributed over both hydrogeological regimes in addition to one water sample collected from Bahr Youssef, the main source of freshwater for the Faiyum province. Chemical analyses were made collaboratively. The major ion geochemical evolution of the drainage water recharging the El Raiyan depression was examined. Geochemically, the Bahr Youssef sample is considered the starting point in the geochemical evolution of the studied surface water. In the cultivated area, major-ion chemistry is generally influenced by chemical weathering of rocks and minerals that are associated with anthropogenic inputs, as well as diffuse urban and/or agricultural drainage. In the depression lakes, the water chemistry generally exhibits an evaporation-dependent evolutionary trend that is further modified by cation exchange and precipitation of carbonate minerals. PMID:26644942

  14. Deserts of China

    USGS Publications Warehouse

    Walker, Alta S.

    1982-01-01

    Improving arid land quality requires an understanding of the original state of the land and its relationship to wind, water, and plant regimes, as well as understanding of interactions within the present ecosystem.  Chinese scientists and local residents have made significant advances in improving arid environments in gobi and sandy deserts and in less arid sandy lands.  Wind patterns are being changed by planting forest belts to protect oases and sandy lands, and on a smaller scale by planting grasses and shrubs or constructing straw grids.  Research on reclamation of deserts is now focusing on how sand-fixing plants may be adapted to local environments, and how the resources of grazing land and water may be effectively exploited without being overused.

  15. Environmental Processes and Spectral Reflectance Characteristics Associated with Soil Erosion in Desert Fringe Regions

    NASA Technical Reports Server (NTRS)

    Jacobberger, P. A.

    1987-01-01

    Results of analysis of spectral variation of sand dunes in El Ghorabi, Bahariya, Egypt; Tombouctou/Azaouad, Mali; and Tsodilo Hills, western Botswana are presented. Seasonal variations in dune extent and location of dune crests and their relationship to such factors as wind and weather variations are emphasized.

  16. Namib Desert, Namibia, Africa

    NASA Technical Reports Server (NTRS)

    1990-01-01

    One of the driest regions on Earth, the Namib Desert, Namibia, Africa (23.0N, 15.0E) lies adjacent to the Atlantic coast but upwelling oceanic water causes a very stable rainless atmosphere. The few local inland rivers do not reach the sea but instead appear as long indentations where rivers penetrate the dune fields and end as small dry lakes. The vast dune fields are the result of sands deposited over millions of years by the stream flow.

  17. Namib Desert, Namibia, Africa

    NASA Technical Reports Server (NTRS)

    1990-01-01

    One of the driest regions on Earth, the Namib Desert, Namibia, Africa (23.0N, 15.0E) lies adjacent to the Atlantic coast but the upwelling oceanic water causes a very stable rainless atmosphere. The few local inland rivers do not reach the sea but instead, appear as long indentations where they penetrate the dune fields and end as small dry lakes. The vast dune fields are the result of sands deposited over millions of years by the stream flow.

  18. Unchanging Desert Sand Dunes

    NASA Astrophysics Data System (ADS)

    Gadhiraju, S.; Banerjee, B.; Buddhiraju, K.; Shah, V.

    2013-12-01

    Deserts are one of the major landforms on earth. They occupy nearly 20% of the total land area but are relatively less studied. With the rise in human population, desert regions are being gradually occupied for settlement posing a management challenge to the concerned authorities. Unrestrained erosion is generally a feature of bare dunes. Stabilized dunes, on the other hand, do not undergo major changes in textures, and can thus facilitate the growth of vegetation. Keeping in view of the above factors, better mapping and monitoring of deserts and particularly of sand dunes is needed. Mapping dunes using field instruments is very arduous and they generate relatively sparse data. In this communication, we present a method of clustering and monitoring sand dunes through imagery captured by remote sensing sensors. Initially Radon spectrum of an area is obtained by decomposition of the image into various projections sampled at finer angular directions. Statistical features such as mode, entropy and standard deviation of Radon spectrum are used in delineation and clustering of regions with different dune orientations. These clustered boundaries are used to detect if there are any changes occurring in the dune regions. In the experiment's, remote sensing data covering various dune regions of the world are observed for possible changes in dune orientations. In all the cases, it is seen that there are no major changes in desert dune orientations. While these findings have implications for understanding of dune geomorphology and changes occurring in dune directions, they also highlight the importance of a wider study of dunes and their evolution both at regional and global scales. Results for Dataset 1 & Dataset 2 Results for Dataset 3

  19. Probabilistic earthquake hazard analysis for Cairo, Egypt

    NASA Astrophysics Data System (ADS)

    Badawy, Ahmed; Korrat, Ibrahim; El-Hadidy, Mahmoud; Gaber, Hanan

    2016-04-01

    Cairo is the capital of Egypt and the largest city in the Arab world and Africa, and the sixteenth largest metropolitan area in the world. It was founded in the tenth century (969 ad) and is 1046 years old. It has long been a center of the region's political and cultural life. Therefore, the earthquake risk assessment for Cairo has a great importance. The present work aims to analysis the earthquake hazard of Cairo as a key input's element for the risk assessment. The regional seismotectonics setting shows that Cairo could be affected by both far- and near-field seismic sources. The seismic hazard of Cairo has been estimated using the probabilistic seismic hazard approach. The logic tree frame work was used during the calculations. Epistemic uncertainties were considered into account by using alternative seismotectonics models and alternative ground motion prediction equations. Seismic hazard values have been estimated within a grid of 0.1° × 0.1 ° spacing for all of Cairo's districts at different spectral periods and four return periods (224, 615, 1230, and 4745 years). Moreover, the uniform hazard spectra have been calculated at the same return periods. The pattern of the contour maps show that the highest values of the peak ground acceleration is concentrated in the eastern zone's districts (e.g., El Nozha) and the lowest values at the northern and western zone's districts (e.g., El Sharabiya and El Khalifa).

  20. Deserts and Arid Lands

    NASA Astrophysics Data System (ADS)

    Brown, Glen F.

    The exponential growth of global population and often concomitant degradation of the environment has forced human expansion into the more hostile and less well-known terrains of arid lands and deserts. Drought in the African Sahel, with recent wholesale movement of tribes seeking survival, has focused interest in such regions. However, geologic and geomorphic knowledge of deserts has expanded slowly until the last few decades. For instance, the arid cycle of erosion, as conceived by William Morse Davis (now deceased; formerly, Harvard University, Cambridge, Mass.), with modifications by W. Penck (now deceased; formerly, Leipzig University, Leipzig, German Democratic Republic), and L. C. King (University of Natal and Durban, South Africa), has dominated desert geomorphological deductions until recently. Since World War II and the verification of plate tectonics, the knowledge of arid lands has increased dramatically, especially in synoptic mapping from remote sensing data and space photography, which transcends political boundaries, thanks to the open skies policy of the U.S. space pioneers.

  1. The Desert Crossings of Mars

    NASA Astrophysics Data System (ADS)

    Cockell, C. S.

    Apart from the polar caps, the Martian volcanoes and the Valles Marineris, ~80% of the martian surface can essentially be classified as `desert'. The methods used to explore Mars, the scientific priorities and the philo- sophical and historical precedents that drive human exploration on Mars will primarily come from our experiences in terrestrial deserts. Here, the methods and approaches used for terrestrial desert expeditions are discussed with reference to Mars. Some of the physical challenges such as low temperature and frost formation will be akin to cold polar desert exploration on Earth. However, some challenges, such as dust storms and lack of liquid water will be akin to hot desert exploration. Expeditions that draw the appropriate lessons from both hot and cold desert terrestrial expeditions will succeed. Examples of major regions on Mars that might be regarded as significant exploratory challenges for expeditions are identified. Key parameters of these expeditions including distance and plausible scientific objectives are provided.

  2. Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health

    PubMed Central

    Köberl, Martina; Müller, Henry; Ramadan, Elshahat M.; Berg, Gabriele

    2011-01-01

    Background To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. Methodology/Principal Findings We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. Conclusions/Significance After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher

  3. Gender, Sibship Composition, and Education in Egypt

    ERIC Educational Resources Information Center

    Tfaily, Rania

    2016-01-01

    This article examines the relationship between gender, sibship, and education over time in Egypt, focusing on how the number, sex, and birth order configuration of siblings affected boys' and girls' education during 1991-2008, a period characterized by significant social and economic changes in Egypt. This study disaggregates schooling into…

  4. Egypt: Beyond Pharaohs, Feluccas and Fellahin.

    ERIC Educational Resources Information Center

    Holt, Evelyn R.

    In a random study of five middle school social studies textbooks available for adoption in the state of Indiana in 1984, great variation in the treatment of Egypt was noted. Coverage of contemporary history was incomplete in all cases. All texts dealt with Egypt's ancient history, but what was reported was questionable. Only one text addressed in…

  5. Women--Sex Objects in Ancient Egypt.

    ERIC Educational Resources Information Center

    Mutimer, Brian T. P.

    Although it has been said that the women in Ancient Egypt enjoyed a reasonable state of social and professional equality with men, this paper presents an alternate theory--that women were second-class citizens whose physical prowess was secondary to their role as sex objects. It appears that men and women in Ancient Egypt often participated in the…

  6. Inclusiveness in Higher Education in Egypt

    ERIC Educational Resources Information Center

    Cupito, Emily; Langsten, Ray

    2011-01-01

    In Egypt, before 1952, education, especially higher education, was the province of a privileged few. After the 1952 Revolution, in pursuit of social justice and economic development, Egypt's leaders eliminated fees, instituted a universal admission examination, promised government employment to all graduates of higher education, and expanded the…

  7. Jeeps Penetrating a Hostile Desert

    ERIC Educational Resources Information Center

    Bailey, Herb

    2009-01-01

    Several jeeps are poised at base camp on the edge of a desert aiming to escort one of them as far as possible into the desert, while the others return to camp. They all have full tanks of gas and share their fuel to maximize penetration. In a friendly desert it is best to leave caches of fuel along the way to help returning jeeps. We solve the…

  8. Microbial origin of desert varnish.

    PubMed

    Dorn, R I; Oberlander, T M

    1981-09-11

    Scanning electron microscopy and energy dispersive x-ray analyses of desert varnish reveal that microorganisms concentrate ambient manganese that becomes greatly enhanced in brown to black varnish. Specific characteristics of desert varnish and of varnish bacteria support a microbial origin for manganese-rich films. Varnish microbes can be cultured and produce laboratory manganese films. Accordingly, natural desert varnish and also manganese-rich rock varnishes in nondesert environments appear to be a product of microbial activity. PMID:17744757

  9. Structural influence on the evolution of the pre-Eonile drainage system of southern Egypt: Insights from magnetotelluric and gravity data

    NASA Astrophysics Data System (ADS)

    Roden, Jeff; Abdelsalam, Mohamed G.; Atekwana, Estella; El-Qady, Gad; Tarabees, Elhamy Aly

    2011-12-01

    The Wadi Kubbaniya in the Western Desert of Egypt north of the City of Aswan has been interpreted as the downstream continuation of the Wadi Abu Subeira, comprising an ancient W- and NW-flowing river system originating from the Precambrian crystalline rocks of the Red Sea Hills which were uplifted during the Miocene in association with the opening of the Red Sea. This drainage system is thought to have been active before the onset of the N-flowing Egyptian Nile which started ˜6 Ma with the Eonile phase; an event that resulted in carving of ˜1000 km long canyon (the Eonile canyon) extending from the Mediterranean Sea in the north to Aswan in the south due to the Messinian Salinity Crisis. This study utilizes geophysical data to examine the role of regional tectonics and local structures in controlling the evolution of the pre-Eonile drainage system. Magnetotelluric (MT) and gravity surveys were conducted along two ˜5 km-long profiles across the NW-trending Wadi Kubbaniya. Two-dimensional (2D) inversion of MT data and gravity models indicate the Wadi Kubbaniya is filled with loosely-consolidated sandstone and conglomerate that extend to a depth of ˜150-200 m into Cretaceous sandstone formations which overlie Precambrian crystalline rocks. These results were evaluated in terms of two end-member models; an incision model in which the 150-200 m thick sedimentary rocks were considered as being deposited within an incised valley that was carved into bedrock, or a structural model in which the sedimentary rocks are considered as filling a NW-trending graben controlled by normal faults that deform the Cretaceous sandstone formations and the underlying Precambrian crystalline rocks. Geological observations as well as supporting seismic data favor the interpretation that the Wadi Kubbaniya is a NW-trending graben similar to other extensional structures found 400 km northwest along-strike of Wadi Kubbaniya. These structures are impressively parallel to the western

  10. Microearthquake studies in Egypt carried out by the geological survey of Egypt

    NASA Astrophysics Data System (ADS)

    Boulos, Fouad K.; Morgan, Paul; Toppozada, Tousson R.

    1987-07-01

    Extensive microearthquake studies have been conducted in Egypt as a joint project between scientists from the Egyptian Geological Survey and Mining Authority (EGSMA) and U.S. scientists. At this stage, a great part of the data has been analyzed and two intensively active areas have been located: one in the Abu Dabbab area of the Eastern Desert, the second at the mouth of the Gulf of Suez near Gubal Island (Daggett et al., 1980). Both sites have been reported to be the epicenters of large earthquakes in 1955 and 1969, respectively. A few scattered earthquakes have also been located in the northern part of the Red Sea, some of which lie along its median axis (Daggett et al., 1986) adding to evidence for the medial opening of the northern Red Sea. After the occurrence of an earthquake (M = 5.5) in the Aswan region on 14 November 1981, continuous recording of the many aftershocks was carried out by EGSMA for about seven months from December 1981 to July 1982, when the temporary network was replaced by a network of telemetered seismographs installed and operated by Helwan Institute of Astronomy and Geophysics in cooperation with scientists from Lamont and Doherty Geological Observatory (LDGO). The majority of epicenters are concentrated in the vicinity of G. Marawa about 65 km upstream of Aswan Dam, along the E-W Kalabsha fault. The observed focal mechanism is consistent with a right-lateral strike-slip motion on the Kalabsha fault. Analysis of Aswan microearthquakes has been done by EGSMA in cooperation with scientists from California Division of Mines and Geology (CDMG).

  11. Factors influencing the rates, processes and magnitude of accumulation of carbon in desert soils

    NASA Technical Reports Server (NTRS)

    Mcfadden, Leslie D.

    1994-01-01

    This report summarizes research funded through NASA's Soil Landscape Climate Program which includes studies of the systematics of carbon storage and flux in the terrestrial environment, specifically terrestrial soils. Efforts focussed on the nature of carbon behavior in arid environments, where the majority of the carbon is present as inorganic carbon stored as pedogenic carbonate in desert calcic soils. Studies were supported of soils in two areas of western North America's major deserts: the Mojave Desert and the Chihuahuan Desert. Part 1 of this report summarizes the results of research conducted in the area of the Providence Mountains, California in the eastern Mojave Desert. Part 2 of this report summarizes the results of research in the Sevilleta Wildlife Refuge in central New Mexico, one of the sites of the UMN Biology Department's Long Term Ecological Research.

  12. Factors influencing the rates, processes and magnitude of accumulation of carbon in desert soils

    NASA Astrophysics Data System (ADS)

    McFadden, Leslie D.

    This report summarizes research funded through NASA's Soil Landscape Climate Program which includes studies of the systematics of carbon storage and flux in the terrestrial environment, specifically terrestrial soils. Efforts focussed on the nature of carbon behavior in arid environments, where the majority of the carbon is present as inorganic carbon stored as pedogenic carbonate in desert calcic soils. Studies were supported of soils in two areas of western North America's major deserts: the Mojave Desert and the Chihuahuan Desert. Part 1 of this report summarizes the results of research conducted in the area of the Providence Mountains, California in the eastern Mojave Desert. Part 2 of this report summarizes the results of research in the Sevilleta Wildlife Refuge in central New Mexico, one of the sites of the UMN Biology Department's Long Term Ecological Research.

  13. Space Radar Image of Safsaf Oasis, Egypt

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-frequency space radar image of south-central Egypt demonstrates the unique capability of imaging radar to penetrate thin sand cover in arid regions to reveal hidden details below the surface. Nearly all of the structures seen in this image are invisible to the naked eye and to conventional optical satellite sensors. Features appear in various colors because the three separate radar wavelengths are able to penetrate the sand to different depths. Areas that appear red or orange are places that can be seen only by the longest wavelength, L-band, and they are the deepest of the buried structures. Field studies in this area indicate L-band can penetrate as much as 2 meters (6.5 feet) of very dry sand to image buried rock structures. Ancient drainage channels at the bottom of the image are filled with sand more than 2 meters (6.5 feet) thick and therefore appear dark because the radar waves cannot penetrate them. The fractured orange areas at the top of the image and the blue circular structures in the center of the image are granitic areas that may contain mineral ore deposits. Scientists are using the penetrating capabilities of radar imaging in desert areas in studies of structural geology, mineral exploration, ancient climates, water resources and archaeology. This image is 51.9 kilometers by 30.2 kilometers (32.2 miles by 18.7 miles) and is centered at 22.7 degrees north latitude, 29.3degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is X-band, vertically transmitted and received. The image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on April 16, 1994, on board the space shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission

  14. Workshop on Extraterrestrial Materials from Cold and Hot Deserts

    NASA Technical Reports Server (NTRS)

    Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

    1999-01-01

    Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalog of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modern falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering

  15. Workshop on Extraterrestrial Materials from Cold and Hot Deserts

    NASA Technical Reports Server (NTRS)

    Schultz, Ludolf (Editor); Franchi, Ian A. (Editor); Reid, Arch M. (Editor); Zolensky, Michael E. (Editor)

    2000-01-01

    Since 1969 expeditions from Japan, the United States, and European countries have recovered more than 20,000 meteorite specimens from remote ice fields of Antarctica. They represent approximately 4000-6000 distinct falls, more than all non-Antarctic meteorite falls and finds combined. Recently many meteorite specimens of a new "population" have become available: meteorites from hot deserts. It turned out that suitable surfaces in hot deserts, like the Sahara in Africa, the Nullarbor Plain in Western and South Australia, or desert high plains of the U.S. (e.g., Roosevelt County, New Mexico), contain relatively high meteorite concentrations. For example, the 1985 Catalogue of Meteorites of the British Museum lists 20 meteorites from Algeria and Libya. Today, 1246 meteorites finds from these two countries have been published in MetBase 4.0. Four workshops in 1982, 1985, 1988, and 1989 have discussed the connections between Antarctic glaciology and Antarctic meteorites, and the differences between Antarctic meteorites and modem falls. In 1995, a workshop addressed differences between meteorites from Antarctica, hot deserts, and modem falls, and the implications of possible different parent populations, infall rates, and weathering processes. Since 1995 many more meteorites have been recovered from new areas of Antarctica and hot deserts around the world. Among these finds are several unusual and interesting specimens like lunar meteorites or SNCs of probable martian origin. The Annual Meeting of the Meteoritical Society took place in 1999 in Johannesburg, South Africa. As most of the recent desert finds originate from the Sahara, a special workshop was planned prior to this meeting in Africa. Topics discussed included micrometeorites, which have been collected in polar regions as well as directly in the upper atmosphere. The title "Workshop on Extraterrestrial Materials from Cold and Hot Deserts" was chosen and the following points were emphasized: (1) weathering

  16. The Kamil Crater in Egypt.

    PubMed

    Folco, Luigi; Di Martino, Mario; El Barkooky, Ahmed; D'Orazio, Massimo; Lethy, Ahmed; Urbini, Stefano; Nicolosi, Iacopo; Hafez, Mahfooz; Cordier, Carole; van Ginneken, Matthias; Zeoli, Antonio; Radwan, Ali M; El Khrepy, Sami; El Gabry, Mohamed; Gomaa, Mahomoud; Barakat, Aly A; Serra, Romano; El Sharkawi, Mohamed

    2010-08-13

    We report on the detection in southern Egypt of an impact crater 45 meters in diameter with a pristine rayed structure. Such pristine structures are typically observed on atmosphereless rocky or icy planetary bodies in the solar system. This feature and the association with an iron meteorite impactor and shock metamorphism provides a unique picture of small-scale hypervelocity impacts on Earth's crust. Contrary to current geophysical models, ground data indicate that iron meteorites with masses of the order of tens of tons can penetrate the atmosphere without substantial fragmentation. PMID:20651117

  17. Libyan Desert, Libya, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Desert landscapes such as this part of the northern Sahara (27.0N, 11.0E) may be analogous to other planets which have no soil or plant growth. The dark rocks in this view are probably volcanic in origin and have many stream beds leading into the dune areas. These stream beds carry sediments towards the lower terrain where the water evaporates, leaving the sediments to be wind blown into the complex dune patterns. The red color comes from iron oxides.

  18. Space Radar Image of Giza Egypt - with enlargement

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This radar image shows the area west of the Nile River near Cairo, Egypt. The Nile River is the dark band along the right side of the image and it flows approximately due North from the bottom to the right. The boundary between dense urbanization and the desert can be clearly seen between the bright and dark areas in the center of the image. This boundary represents the approximate extent of yearly Nile flooding which played an important part in determining where people lived in ancient Egypt. This land usage pattern persists to this day. The pyramids at Giza appear as three bright triangles aligned with the image top just at the boundary of the urbanized area. They are also shown enlarged in the inset box in the top left of the image. The Great Pyramid of Khufu (Cheops in Greek) is the northern most of the three Giza pyramids. The side-looking radar illuminates the scene from the top, the two sides of the pyramids facing the radar reflect most of the energy back to the antenna and appear radar bright; the two sides away from the radar reflect less energy back and appear dark Two additional pyramids can be seen left of center in the lower portion of the image. The modern development in the desert on the left side of the image is the Sixth of October City, an area of factories and residences started by Anwar Sadat to relieve urban crowding. The image was taken on April 19, 1994 by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the shuttle Endeavour. SIR-C/X-SAR, a joint mission of the German, Italian and the United States space agencies, is part of NASA's Mission to Planet Earth. The image is centered on latitude 29.72 degrees North latitude and 30.83 degrees East longitude. The area shown is approximately 20 kilometers by 30 kilometers. The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band horizontally transmitted, horizontally received; green is C

  19. Impact of Geoethics in Egypt

    NASA Astrophysics Data System (ADS)

    AbdelMakosud, kholoud Mohamed; Ezzat, Nada

    2016-04-01

    Geoethics, is a new term that could be unknown in the Arab world,where its translation in Arabic language make some kind of problems,with special emphasis on Egypt; spreading this term and the importance of it to professionals and un professionals is not an easy task.Culture and awareness problems face us on dealing with it. In this working paper the researchers study two levels of educational samples, the first one is of young geo-scientists and the other one is of young people of different disciplines to make over view survey (monitoring the base level) about knowing geoethics and another survey after applying some lectures and workshops to the same samples to monitor the second level. The aim of the research is to find out how people will accept this term and its application and how we can spread it through community with different effective ways. In Egypt there are some kind of culture problems could affect on spreading of any new concept, these problems could be overcome by some scientific, social and culture recommendations, these recommendations could be applied in both Arab countries and African Countries with few modifications.

  20. Desert landscape irrigation

    SciTech Connect

    Quinones, R.

    1995-06-01

    Industrialization can take place in an arid environment if a long term, overall water management program is developed. The general rule to follow is that recharge must equal or exceed use. The main problem encountered in landscape projects is that everyone wants a lush jungle setting, tall shade trees, ferns, with a variety of floral arrangements mixed in. What we want, what we can afford, and what we get are not always the same. Vegetation that requires large quantities of water are not native to any desert. Surprisingly; there are various types of fruit trees, and vegetables that will thrive in the desert. Peaches, plums, nut trees, do well with drip irrigation as well as tomatoes. Shaded berry plans will also do well, the strawberry being one. In summary; if we match our landscape to our area, we can then design our irrigation system to maintain our landscape and grow a variety of vegetation in any arid or semiarid environment. The application of science and economics to landscaping has now come of age.

  1. Supersymmetry without the Desert

    SciTech Connect

    Nomura, Yasunori; Poland, David

    2006-09-26

    Naturalness of electroweak symmetry breaking in weak scale supersymmetric theories may suggest the absence of the conventional supersymmetric desert. We present a simple, realistic framework for supersymmetry in which (most of) the virtues of the supersymmetric desert are naturally reproduced without having a large energy interval above the weak scale. The successful supersymmetric prediction for the low-energy gauge couplings is reproduced due to a gauged R symmetry present in the effective theory at the weak scale. The observable sector superpotential naturally takes the form of the next-to-minimal supersymmetric standard model, but without being subject to the Landau pole constraints up to the conventional unification scale. Supersymmetry breaking masses are generated by the F-term and D-term VEVs of singlet and U(1){sub R} gauge fields, as well as by anomaly mediation, at a scale not far above the weak scale. We study the resulting pattern of supersymmetry breaking masses in detail, and find that it can be quite distinct. We construct classes of explicit models within this framework, based on higher dimensional unified theories with TeV-sized extra dimensions. A similar model based on a non-R symmetry is also presented. These models have a rich phenomenology at the TeV scale, and allow for detailed analyses of, e.g., electroweak symmetry breaking.

  2. Orbital and Ground-penetrating Radar Studies of Mars-analog Terrain in Egypt

    NASA Astrophysics Data System (ADS)

    Maxwell, T. A.; Grant, J. A.; Campbell, B. A.

    2007-05-01

    Several study groups have endorsed the concept of flying an imaging synthetic aperture radar (SAR) in orbit that would penetrate areas of thin surface cover revealing underlying terrain and providing additional information on surface roughness, physical properties and composition. Egypt provides many excellent terrestrial field sites to study both the processes that we expect to be revealed in a Mars SAR Mission, as well as the stratigraphic setting of past depositional environments that are similar to those seen in southern Egypt. We have used terrestrial orbital radar data for southern Egypt, comparing geologic materials and boundaries mapped in the field and with visible wavelengths (from Landsat) to those discerned via Shuttle Imaging Radar (SIR) -C, and field checking key sites to determine the depth, physical characteristics and types of geologic boundaries that contribute to the radar returns. In addition to stratigraphic mapping of the thickness and extent of near-surface units in the field, we have used ground-penetrating radar (GPR) to determine the lateral extent and depth of subsurface interfaces. In this manner, we expect to learn more about the capabilities and limitations of orbital and ground-based systems, the trade-offs between frequency, polarization and resolution in Mars-like terrain for detecting buried interfaces and structures, and more about the geologic history of southern Egypt. Several studies have concentrated on one of the areas of prominent radar-detected channels near Bir Safsaf in the southwest desert, we have concentrated on the Bir Kiseiba region, an area where the mixture of gravel spreads, buried paleochannels, and alluvium creates a setting that may mimic outflow deposit locations on Mars. While bedrock incised channels may stand out in SAR images because of a near-surface, sharp dielectric interface (such as those at Safsaf and in northern Sudan), the more complex problem of distinguishing fluvial patterns in Mars

  3. A Microscopists View of Desert Varnish from the Sonoran Desert

    NASA Astrophysics Data System (ADS)

    Garvie, L. A. J.; Burt, D. M.; Buseck, P. R.

    2009-03-01

    Nanometer-scale element mapping and spectroscopy of desert varnish reveals a dynamic disequilibrium system characterized by post-depositional mineralogical, chemical, and structural changes, activated by liquid water.

  4. Genome sequences of SAT 2 foot-and-mouth disease viruses from Egypt and Palestinian Autonomous Territories (Gaza Strip).

    PubMed

    Valdazo-González, Begoña; Knowles, Nick J; Hammond, Jef; King, Donald P

    2012-08-01

    Two foot-and-mouth disease virus (FMDV) genome sequences have been determined for isolates collected from recent field outbreaks in North Africa (Egypt) and the Middle East (Palestinian Autonomous Territories). These data represent the first examples of complete genomic sequences for the FMDV SAT 2 topotype VII, which is thought to be endemic in countries immediately to the south of the Sahara desert. Further studies are now urgently required to provide insights into the epidemiological links between these outbreaks and to define the pathogenicity of this emerging lineage. PMID:22843860

  5. Genome Sequences of SAT 2 Foot-and-Mouth Disease Viruses from Egypt and Palestinian Autonomous Territories (Gaza Strip)

    PubMed Central

    Valdazo-González, Begoña; Knowles, Nick J.; Hammond, Jef

    2012-01-01

    Two foot-and-mouth disease virus (FMDV) genome sequences have been determined for isolates collected from recent field outbreaks in North Africa (Egypt) and the Middle East (Palestinian Autonomous Territories). These data represent the first examples of complete genomic sequences for the FMDV SAT 2 topotype VII, which is thought to be endemic in countries immediately to the south of the Sahara desert. Further studies are now urgently required to provide insights into the epidemiological links between these outbreaks and to define the pathogenicity of this emerging lineage. PMID:22843860

  6. Evolutionary hotspots in the Mojave Desert

    USGS Publications Warehouse

    Vandergast, Amy G.; Inman, Richard D.; Barr, Kelly R.; Nussear, Kenneth E.; Esque, Todd C.; Hathaway, Stacie A.; Wood, Dustin A.; Medica, Philip A.; Breinholt, Jesse W.; Stephen, Catherine L.; Gottscho, Andrew D.; Marks, Sharyn B.; Jennings, W. Bryan; Fisher, Robert N.

    2013-01-01

    Genetic diversity within species provides the raw material for adaptation and evolution. Just as regions of high species diversity are conservation targets, identifying regions containing high genetic diversity and divergence within and among populations may be important to protect future evolutionary potential. When multiple co-distributed species show spatial overlap in high genetic diversity and divergence, these regions can be considered evolutionary hotspots. We mapped spatial population genetic structure for 17 animal species across the Mojave Desert, USA. We analyzed these in concurrence and located 10 regions of high genetic diversity, divergence or both among species. These were mainly concentrated along the western and southern boundaries where ecotones between mountain, grassland and desert habitat are prevalent, and along the Colorado River. We evaluated the extent to which these hotspots overlapped protected lands and utility-scale renewable energy development projects of the Bureau of Land Management. While 30–40% of the total hotspot area was categorized as protected, between 3–7% overlapped with proposed renewable energy project footprints, and up to 17% overlapped with project footprints combined with transmission corridors. Overlap of evolutionary hotspots with renewable energy development mainly occurred in 6 of the 10 identified hotspots. Resulting GIS-based maps can be incorporated into ongoing landscape planning efforts and highlight specific regions where further investigation of impacts to population persistence and genetic connectivity may be warranted.

  7. Challenge of a desert: revegetation of disturbed desert lands

    SciTech Connect

    Wallace, A.; Romney, E.M.; Hunter, R.B.

    1980-01-01

    The revegetation of disturbed, arid lands is one of the great challenges of a desert. An attempt to encourage it is not an impossible task, however, if the natural and the man-made resources available are utilized and managed. Where rainfall and temperature conditions approach or exceed those of the Great Basin desert, restoration of disturbed land will occur through natural revegetation processes within a reasonable period of time. This is not generally the case in the more arid Mojave Desert areas where the moisture and temperature conditions are less favorable for germination and seedling survival. Restoration of vegetation by natural reseeding can, however, occur within local sites where moisture has concentrated as the result of terrain features forming catchment basins. Otherwise, the natural revegetation processes in the Mojave Desert areas require much longer periods of time (possibly decades or centuries) than are practical for meeting environmental protection standards imposed by current legislation. Through better understanding of the processes governing revegetation and the ability to control them, it is possible for man to more rapidly restore disturbed desert lands. Terrain manipulation to form moisture catchment basins, selection of seed from pioneering shrub species, preservation of existing shrub clump fertile islands in the soil, supplemental fertilization, irrigation, organic amendments, and transplanting vigorous shrub species are some of the important things that can be done to help restore disturbed desert land.

  8. Keeping the desert at bay

    SciTech Connect

    El-Kassas, M.

    1981-02-01

    Man-made desert (areas that are no longer productive) has increased the world's deserts from 36.3 to 43% of the land surface. Desertification involves ecological degradation that makes the land less productive or allows an uneconomic type of vegetation, such as mesquite, to replace an economic plant. The process was first thought to be an encroachment by expanding deserts, but, except for the movement of sand dunes, desertification is now viewed as productive land that deteriorated and was added to the desert. Land is lost to agriculture by erosion, loss of nutrients, compaction, salination, urban development, and pollution. The interacting biosphere, technosphere, and social sphere form the framework of man's existence. An understanding of this framework is crucial to those offering technological assistance to developing countries. (DCK)

  9. Mate desertion in the snail kite

    USGS Publications Warehouse

    Beissinger, S.R.; Snyder, N.F.R.

    1988-01-01

    Mate desertion during the breeding cycle was documented at 28 of 36 (78%) snail kite, Rostrhamus sociabilis nests in Florida between 1979 and 1983. Offspring mortality occurred at only one deserted nest, however. Parents that were deserted by their mates continued to care for their young until independence (3?5 additional weeks) and provided snails at a rate similar to that of both parents combined before desertion. Males and females deserted with nearly equal frequency, except in 1982 when more females deserted. No desertion occurred during drought years, whereas desertion occurred at nearly every nest during favourable conditions. The occurrence of mate desertion was generally related to indirect measures of snail abundance: foraging range, snail delivery rates to the young and growth rates. Small broods were deserted more frequently by females than by males and tended to be deserted earlier than large ones. After desertion, deserters had the opportunity to re-mate and nest again since breeding seasons were commonly lengthy, but whether they did so was impossible to determine conclusively in most cases. The deserted bird sometimes incurred increased energetic costs and lost breeding opportunities during periods of monoparental care.

  10. Opportunities for woody crop production using treated wastewater in Egypt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Nile River provides nearly 97% of Egypt's freshwater supply. Egypt's share of Nile waters is allocated according to international treaty obligations and is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the N...

  11. Desert and desertification in Iran

    NASA Astrophysics Data System (ADS)

    Bahrami, M.

    2009-04-01

    One of the greatest environmental concerns in Iran as in other arid and semiarid countries is the transformation of once productive, or marginally productive, land to deteriorated land and soil unable to support plants and animals. Because the land becomes barren and dry, the process is described as desertification, which occurs as a sequence of events. The area of deserts in Iran is about 340,000 Km2 (less than one fifth of its total area), of which 100,000 Km2 is being used for some cultivation, 120,000 Km2 is subjected to moving sands about 40 % of which is active sand dunes. Most of features and processes usual in world famous deserts are also observed in Iran: low precipitation, high evaporation, poor or lack of vegetation, saline and alkaline soils, low population and small and sparse oases. The deserts of Iran are generally classified in the subtropical, warm, arid and semiarid group, but the effect and presence of some geographical and geoclimatical factors such as height, vicinity to Indian Ocean and so on do some changes in climatic conditions and geographical features causing some local and regional differences in them. Geographically, two groups of deserts have been known in Iran: (1) Coastal deserts which, like a ribbon with variable width, stretch from extreme southeast to extreme southwest, at the north parts of Oman Sea and Persian Gulf. One important feature of these deserts is relatively high humidity which differentiates them from other deserts. This causes an increase in vegetation coverage and hence a decrease in eolian erosion and also a dominance of chemical weathering to that of physical. (2) internal deserts, which rest in central, eastern and southeastern plateau of the country and in independent and semi dependent depressions. This situation, which is due to the surrounding high mountains, blocks humidity entry and causes the aridity of these deserts. Wind as a dominant process in the area causes deflated features such as Reg (desert

  12. Original sounding and drifting balloon-borne measurements in the western Mediterranean with the aerosol counter/sizer LOAC during summer ChArMEx campaigns, with a focus on desert dust events

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Dulac, François; Vignelles, Damien; Jeannot, Matthieu; Verdier, Nicolas; Chazette, Patrick; Crenn, Vincent; Sciare, Jean; Totems, Julien; Durand, Pierre; Barret, Brice; Jambert, Corinne; Mallet, Marc; Menut, Laurent; Mailler, Sylvain; Basart, Sara; Baldasano, José Maria

    2015-04-01

    LOAC (Light Optical Aerosol Counter) is a new small optical particle counter/sizer of ~250 grams designed to fly under all kinds of balloons. The measurements are conducted at two scattering angles (12° and 60°), allowing the determination of the aerosol particle concentrations in 19 size classes within a diameter range of ~0.2-100 µm and some identification of the nature of particles dominating different size classes. Following laboratory calibration, the sensor particularly discriminates wet or liquid particles, mineral dust, soot carbon particles and salts. Comparisons with other in situ sensors at the surface and with remote sensing measurements on the vertical were performed to give confidence in measurements. The instrument has been operated at the surface, under all kinds of balloons up to more than 35 km in altitude, including tethered, sounding, open stratospheric and new boundary-layer pressurized drifting balloons (BLPB) from CNES, and was tested on board a small UAV. Operations encompass a variety of environments including the Arctic (Reykjavik, Island, and Kiruna, Sweden), Brazil (Sao Paolo), the western Mediterranean Basin, southwestern France, peri-urban (Ile de France) and urban areas (Paris and Vienna). Presented results are focused on the LOAC balloon-borne measurements performed in the western Mediterranean basin during MISTRALS/ChArMEx campaigns (Mediterranean Integrated Studies aT Regional And Local Scales/the Chemistry-Aerosol Mediterranean Experiment; http://www.mistrals-hjome.org; http://charmex.lsce.ipsl.fr), with a focus on African dust events. Two test flights with a first version of LOAC under sounding balloons were first successfully performed in late June 2012 near Marseille during an intense dust event. In 2013, 19 LOAC flights have been performed under meteorological balloons and 12 under low altitude drifting balloons, most of them from Minorca Island (Spain) in June and early July and others from Levant Island (south of France

  13. Original sounding and drifting balloon-borne measurements in the western Mediterranean with the aerosol counter/sizer LOAC during summer ChArMEx campaigns, with a focus on desert dust events

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Dulac, François; Vignelles, Damien; Jeannot, Matthieu; Verdier, Nicolas; Chazette, Patrick; Crenn, Vincent; Sciare, Jean; Totems, Julien; Durand, Pierre; Barret, Brice; Jambert, Corinne; Mallet, Marc; Menut, Laurent; Mailler, Sylvain; Basart, Sara; Baldasano, José Maria

    2015-04-01

    LOAC (Light Optical Aerosol Counter) is a new small optical particle counter/sizer of ~250 grams designed to fly under all kinds of balloons. The measurements are conducted at two scattering angles (12° and 60°), allowing the determination of the aerosol particle concentrations in 19 size classes within a diameter range of ~0.2-100 µm and some identification of the nature of particles dominating different size classes. Following laboratory calibration, the sensor particularly discriminates wet or liquid particles, mineral dust, soot carbon particles and salts. Comparisons with other in situ sensors at the surface and with remote sensing measurements on the vertical were performed to give confidence in measurements. The instrument has been operated at the surface, under all kinds of balloons up to more than 35 km in altitude, including tethered, sounding, open stratospheric and new boundary-layer pressurized drifting balloons (BLPB) from CNES, and was tested on board a small UAV. Operations encompass a variety of environments including the Arctic (Reykjavik, Island, and Kiruna, Sweden), Brazil (Sao Paolo), the western Mediterranean Basin, southwestern France, peri-urban (Ile de France) and urban areas (Paris and Vienna). Presented results are focused on the LOAC balloon-borne measurements performed in the western Mediterranean basin during MISTRALS/ChArMEx campaigns (Mediterranean Integrated Studies aT Regional And Local Scales/the Chemistry-Aerosol Mediterranean Experiment; http://www.mistrals-hjome.org; http://charmex.lsce.ipsl.fr), with a focus on African dust events. Two test flights with a first version of LOAC under sounding balloons were first successfully performed in late June 2012 near Marseille during an intense dust event. In 2013, 19 LOAC flights have been performed under meteorological balloons and 12 under low altitude drifting balloons, most of them from Minorca Island (Spain) in June and early July and others from Levant Island (south of France

  14. From (b)edouin to (a)borigine: the myth of the desert noble savage.

    PubMed

    Graulund, Rune

    2009-01-01

    This article examines the myth of the supposed superiority of the desert noble savage over civilized man. With the Bedouin of Arabia and the Aborigines of Australia as its two prime examples, the article argues that two versions of this myth can be traced: one in which the desert noble savage is valorized due to his valour, physical prowess and martial skill (Bedouin); and another, later version, where the desert noble savage is valorized as a pacifist, an ecologist and a mythmaker/storyteller (Aborigines). The article concludes by examining the way in which this turn from one type of desert noble savage to another reflects the manner in which western modernity has shifted its values from Cartesian dualities and Enlightenment rationalism to that of networks, potentialities, ecology and myth. PMID:19886291

  15. Comparison of health care financing in Egypt and Cuba: lessons for health reform in Egypt.

    PubMed

    Gericke, C A

    2005-01-01

    Egypt and Cuba are both lower-middle income countries with a history of socialist rule, which have embarked on economic liberalization since the 1990s. Cuba has achieved exemplary health status whereas health status in Egypt is lower than could be expected for its level of income. In this article, health care financing mechanisms in both countries are analysed on their effectiveness, efficiency, and equity, with the objective of identifying the determinants of success in the Cuban health system from which valuable lessons for current health reforms in Egypt may be derived. PMID:16761679

  16. Analysis of utilization of desert habitats with dynamic simulation

    USGS Publications Warehouse

    Williams, B.K.

    1986-01-01

    The effects of climate and herbivores on cool desert shrubs in north-western Utah were investigated with a dynamic simulation model. Cool desert shrublands are extensively managed as grazing lands, and are defoliated annually by domestic livestock. A primary production model was used to simulate harvest yields and shrub responses under a variety of climatic regimes and defoliation patterns. The model consists of six plant components, and it is based on equations of growth analysis. Plant responses were simulated under various combinations of 20 annual weather patterns and 14 defoliation strategies. Results of the simulations exhibit some unexpected linearities in model behavior, and emphasize the importance of both the pattern of climate and the level of plant vigor in determining optimal harvest strategies. Model behaviors are interpreted in terms of shrub morphology, physiology and ecology.

  17. The Landscape Evolution of Ulan Buh Desert in North China during Late Quaternary

    NASA Astrophysics Data System (ADS)

    Chen, Fahu; Li, Guoqiang; Zhao, Hui; Jin, Ming; Fan, Yuxin; Madsen, David; Chun, Xi

    2013-04-01

    Desert evolution was one of the major environmental changes in northern China during Quaternary. Ulan Buh Desert (UBD), at margin of present summer monsoon, is one of main desert fields and dust source areas in the north and northwest China. In this paper we present the results of lithology, Optical Stimulated Luminescence (OSL) dates, grain-size, carbonate content, organic content and pollen analysis from the drilling cores in the different parts of UBD. Our results show that most area of the present Ulan Buh desert was covered by the Jilantai-Hetao mage-paleolake before ~90 ka ago, a uniform paleolake of about 34,000 km2 covering the whole Hetai palin, and sevrious eolian and desert environment was prevailing during the last glacial and early Holoccene. Then an Ulan Buh paleolake (UB paleolake), likely a desert-wetland enviroment, formed in the northern part of UBD and Jilantai salt lake at around 8-7 ka, leaving dry lake bed landform in northern UBD, while high dune landscape probably prevailed in south UBD. After that, the mordern UBD landscape formed. The Jilantai Salt Lake in western UBD continued to exist until present with high lake level during UB paleolake preiod. During the recent 2000 years aeolian sand from Badan Jaran desert invaded the north UBD through Langshan mountain to form dune landform covered on dry UB paleolake bed and seperated main Ulan Buh desert and Jilantai Salt Lake. Human activities such as changing low wetland to farmland and following abandonment resulted the formation of easten Ulan Buh desert in Han dynasty since 200 BC. The formation of UBD landfporms was suggedted to be relate to disintegration of Jilantai-Hetao mage-paleolake, and was also likely to corresponding to summer monsoon changes during during last glacial and Holocene.

  18. Egypt's petrogas plans gas for Cairo homes

    SciTech Connect

    Sharman, R.B.

    1981-12-01

    The first phase of Egypt's program to ultimately convert 640,000 LPG users to natural gas will cover four Cairo suburbs, supply about 160,000 customers, modify some 300,000 appliances, and switch two power plants to gas firing. The Abu el Gharadig field 155 miles west of the city will supply the gas via a new 38-mile transmission line. Most of the new distribution system will use polyethylene pipe. BGC's international Consultancy Service is helping Egypt's Petrogas plan and supervise the ambitious project.

  19. Intercalibration of GOES Imager visible channels over the Sonoran Desert

    NASA Astrophysics Data System (ADS)

    Yu, Fangfang; Wu, Xiangqian; Grotenhuis, Michael; Qian, Haifeng

    2014-07-01

    The Geostationary Operational Environmental Satellites (GOES) have been observing the Western Hemisphere since the late 1970s, providing valuable information for weather forecast and climate change studies. Due to the lack of an onboard calibration device for the visible channel, accurate reflectance of the visible channel data depends on vicarious calibration methods to provide postlaunch calibration coefficients to compensate for the degraded responsivity. In this study, the Sonoran Desert, which can be viewed by both GOES-East and GOES-West satellites, is used to intercalibrate the visible channels on board the three-axis stabilized GOES satellite Imagers traceable to the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 (C6) calibration standard. It was found that when the anomalous reflectance in 2004 and 2005 are excluded, the Sonoran Desert is radiometrically, spatially, and spectrally stable at the GOES viewing geometries and thus can be considered as a pseudo-invariant calibration site to develop long-term GOES Imager visible data set. To characterize the desert target reflectance with the MODIS data, GOES observations over 1 year period are used to convert the MODIS reflectance to the GOES viewing and solar illumination geometries. The spectral band adjustment factor for each GOES Imager visible channel is generated with a set of clear-sky Hyperion measurements. A trending algorithm, which consists of a polynomial function for the description of instrument degradation performance and two sine terms for the impacts of the seasonal variations of the solar zenith angle and atmospheric components, is applied to fit the time series of prelaunch calibrated reflectance. The combined calibration uncertainty of the desert calibration method is less than 4% at the Aqua MODIS C6 calibration standard. The difference of the postlaunch calibration coefficients between the desert calibration and the current GOES visible operational calibration

  20. Biological soil crusts as an integral component of desert environments

    USGS Publications Warehouse

    Belnap, Jayne; Weber, Bettina

    2013-01-01

    The biology and ecology of biological soil crusts, a soil surface community of mosses, lichens, cyanobacteria, green algae, fungi, and bacteria, have only recently been a topic of research. Most efforts began in the western U.S. (Cameron, Harper, Rushforth, and St. Clair), Australia (Rogers), and Israel (Friedmann, Evenari, and Lange) in the late 1960s and 1970s (e.g., Friedmann et al. 1967; Evenari 1985reviewed in Harper and Marble 1988). However, these groups worked independently of each other and, in fact, were often not aware of each other’s work. In addition, biological soil crust communities were seen as more a novelty than a critical component of dryland ecosystems. Since then, researchers have investigated many different aspects of these communities and have shown that although small to microscopic, biological soil crusts are critical in many ecological processes of deserts. They often cover most of desert soil surfaces and substantially mediate inputs and outputs from desert soils (Belnap et al. 2003). They can be a large source of biodiversity for deserts, as they can contain more species than the surrounding vascular plant community (Rosentreter 1986). These communities are important in reducing soil erosion and increasing soil fertility through the capture of dust and the fixation of atmospheric nitrogen and carbon into forms available to other life forms (Elbert et al. 2012). Because of their many effects on soil characteristics, such as external and internal morphological characteristics, aggregate stability, soil moisture, and permeability, they also affect seed germination and establishment and local hydrological cycles. Covering up to 70% of the surface area in many arid and semi-arid regions around the world (Belnap and Lange 2003), biological soil crusts are a key component within desert environments.

  1. Phytoremediation for Oily Desert Soils

    NASA Astrophysics Data System (ADS)

    Radwan, Samir

    This chapter deals with strategies for cleaning oily desert soils through rhizosphere technology. Bioremediation involves two major approaches; seeding with suitable microorganisms and fertilization with microbial growth enhancing materials. Raising suitable crops in oil-polluted desert soils fulfills both objectives. The rhizosphere of many legume and non-legume plants is richer in oil-utilizing micro-organisms than non-vegetated soils. Furthermore, these rhizospheres also harbour symbiotic and asymbiotic nitrogen-fixing bacteria, and are rich in simple organic compounds exuded by plant roots. Those exudates are excellent nutrients for oil-utilizing microorganisms. Since many rhizospheric bacteria have the combined activities of hydrocarbon-utilization and nitrogen fixation, phytoremediation provides a feasible and environmentally friendly biotechnology for cleaning oil-polluted soils, especially nitrogen-poor desert soils.

  2. 76 FR 30002 - Establishment of the Antelope Valley of the California High Desert Viticultural Area

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... Antelope Valley of the California High Desert viticultural area in the Federal Register (75 FR 53877) on... western tip of the valley, is a sedimentary bed dating to the Miocene epoch (about 23 to 5 million years... granitic rock on alluvial fans and terraces. Generally, they vary in drainage, slope, elevation,...

  3. BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM DESERT VEGETATION OF THE SOUTHWESTERN U.S.

    EPA Science Inventory

    Thirteen common plant species in the Mojave and Sonoran Desert regions of the western United States were tested for emissions of biogenic non-methane volatile organic compounds (BVOCs). Only two of the species examined emitted isoprene at rates of 10 µgCg−1 ...

  4. Advantages of endophyte infection for irrigated pastures of semiarid, cold-desert environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little research has evaluated possible endophyte benefits to adaptation and production of grasses in the irrigated pastures of the semiarid, cold-desert environments of the western USA. Severe irrigation shortages are common; however, production demands are increasing, necessitating maximizing tall ...

  5. Phenolic Compounds from the Fruits of Medemia argun, a Food and Medicinal Plant of Ancient Egypt.

    PubMed

    Masullo, Milena; Hamed, Arafa I; Mahalel, Usama A; Pizza, Cosimo; Piacente, Sonia

    2016-03-01

    Medemia argun is a mysterious and little known monotypic fan palm from the Nubian Desert Oases of southern Egypt and northern Sudan. Its fruits have been found in the tombs from the 5th Dynasty (ca. 2500 BC) to Roman times (6-7th century AD), including the celebrated tomb of Tutankhamun. In ancient Egypt, the fruits of this palm were widely distributed and were highly valued, as confirmed by their frequent occurrence in offerings in the tombs. In order to elucidate the chemical composition of the phenolic fraction, phytochemical investigation of the BuOH extract of fruits was carried out to afford eight compounds (1-8), among which was the new 2,4-dihydroxy-6-methylacetophenone 2-0-β-D-glucopyranoside (1). With the aim to investigate if the high shelf life of M argun fruits could be related to the occurrence of antioxidant principles that were able to prevent oxidative reactions, the evaluation was carried out of the in vitro antioxidant activity by Trolox equivalent antioxidant capacity (TEAC) assay of the extract and isolated compounds. PMID:27169174

  6. Enhancing and restoring habitat for the desert tortoise (Gopherus agassizii)

    USGS Publications Warehouse

    Abella, Scott R.; Berry, Kristin H.

    2016-01-01

    Habitat has changed unfavorably during the past 150 years for the desert tortoise (Gopherus agassizii), a threatened species with declining populations in the Mojave and western Sonoran Desert. To support recovery efforts, we synthesized published information on relationships of desert tortoises with three habitat features (cover sites, forage, and soil) and candidate management practices for improving these features for tortoises. In addition to their role in soil health and facilitating recruitment of annual forage plants, shrubs are used by desert tortoises for cover and as sites for burrows. Outplanting greenhouse-grown seedlings, protected from herbivory, has successfully restored (>50% survival) a variety of shrubs on disturbed desert soils. Additionally, salvaging and re-applying topsoil using effective techniques is among the more ecologically beneficial ways to initiate plant recovery after severe disturbance. Some plant species provide better-quality forage than others. Tortoises selectively forage on particular annual and herbaceous perennial species, such as legumes, with favored plants varying with phenological stage within years. Non-native grasses are non-preferred forage and contribute fuel to spreading wildfires, which damage or kill shrubs that tortoises use for cover. Maintaining a diverse "menu" of native annual forbs and decreasing non-native grasses are priorities for restoring most desert tortoise habitats. Reducing herbivory by non-native animals, carefully timing herbicide applications, and strategically augmenting annual forage plants via seeding show promise for improving tortoise forage quality. Roads, another disturbance, negatively affect habitat in numerous ways (e.g., compacting soil, altering hydrology). Techniques such as re-contouring road berms to reestablish drainage patterns, vertical mulching ("planting" dead plant material), and creating barriers to prevent trespasses can assist natural recovery on decommissioned backcountry

  7. A comprehensive study of noble gases and nitrogen in "Hypatia", a diamond-rich pebble from SW Egypt

    NASA Astrophysics Data System (ADS)

    Avice, Guillaume; Meier, Matthias M. M.; Marty, Bernard; Wieler, Rainer; Kramers, Jan D.; Langenhorst, Falko; Cartigny, Pierre; Maden, Colin; Zimmermann, Laurent; Andreoli, Marco A. G.

    2015-12-01

    This is a follow-up study of a work by Kramers et al. (2013) on a very unusual diamond-rich rock fragment found in the area of south west Egypt in the south-western side of the Libyan Desert Glass strewn field. This pebble, called Hypatia, is composed of almost pure carbon. Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD) results reveal that Hypatia is mainly made of defect-rich diamond containing lonsdaleite and multiple deformation bands. These characteristics are compatible with an impact origin on Earth and/or in space. We also analyzed concentrations and isotopic compositions of all five noble gases and nitrogen in several ∼mg sized Hypatia samples. These data confirm the conclusion by Kramers et al. (2013) that Hypatia is extra-terrestrial. The sample is relatively rich in trapped noble gases with an isotopic composition being close to the Q component found in many types of meteorites. 40Ar/36Ar ratios in individual steps are as low as 0.4 ± 0.3. Cosmic-ray produced "cosmogenic" 21Ne is present in concentrations corresponding to a nominal cosmic-ray exposure (CRE) age of roughly 0.1 Myr if produced in a typical meter-sized meteoroid. Such an atypically low nominal CRE age suggests high shielding in a considerably larger body. In addition to the Xe-Q composition, an excess of radiogenic 129Xe (from the decay of short-lived radioactive 129I) is observed (129Xe /132Xe = 1.18 + / - 0.03). Two isotopically distinct N components are present, an isotopically heavy component (δ15N ∼ + 20 ‰) released at low temperatures and a major isotopically light component (δ15N ∼ - 110 ‰) at higher temperatures. This disequilibrium in N suggests that the diamonds in Hypatia were formed in space rather than upon impact on Earth (δN15atm = 0 ‰). All our data are broadly consistent with concentrations and isotopic compositions of noble gases in at least three different types of carbon-rich meteoritic materials: carbon-rich veins in ureilites

  8. Review of Parasitic Zoonoses in Egypt

    PubMed Central

    Youssef, Ahmed I.; Uga, Shoji

    2014-01-01

    This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance. PMID:24808742

  9. Women's "Justification" of Domestic Violence in Egypt

    ERIC Educational Resources Information Center

    Yount, Kathryn M.; Li, Li

    2009-01-01

    We explored the influences of women's social learning, marital resources and constraints, and exposure to norms about women's family roles on their views about wife hitting or beating among 5,450 participants in the 2005 Egypt Demographic and Health Survey. One half justified wife hitting or beating for some reason. Women from rural areas who were…

  10. New leaf diseases of barley in Egypt.

    PubMed

    Mehiar, F F; El-Deen, E; Wasfy, H; El-Samra, I A

    1976-01-01

    Leaf diseases of barley were observed also in Egypt. From leaves of barley were isolated: Helminthosporium teres, H. gramineum, Stemphylium vesicarium, Alternaria triticina, Vlocladium chartarum, Acnemonium kiliense, Stemphylium spec. accompanied with the Pleospora stage. Inoculations on both attached and detached leaves showed that all the tested fungi were pathogenic, except Acremonium kiliense and Ulocladium chartarum. PMID:1037183

  11. Supply and Demand for Graduates in Egypt.

    ERIC Educational Resources Information Center

    Arabsheibani, Gholamreza

    1991-01-01

    Data from a sample of university graduates in Egypt are used to test the effect of a mismatch in higher education policy and labor demand on future employment patterns. The results are delayed employment or underemployment and consequent lowering of lifetime earnings of college graduates. (MSE)

  12. Video Usage in Egypt: Limits and Effects.

    ERIC Educational Resources Information Center

    El-Fawal, Nagwa Amin

    A review of research conducted in Egypt to assess the impact of videocassette recorders (VCRs) on society and on other communication media indicates that the use of VCRs--a new phenomenon in mass communication in that country--has been accelerating over the past five years as more people have been gradually exposed to the advantages of unlimited…

  13. Multicenter Study of Brucellosis in Egypt

    PubMed Central

    Samaha, Hassan; Al-Rowaily, Meshref; Khoudair, Ramadan M.

    2008-01-01

    Brucellosis causes appreciable economic losses in livestock. Examination of milk and tissues from animals in Egypt for Brucella spp. showed increased prevalence rates of serologically reactive animals. All isolates were B. melitensis biovar 3. One Brucella sp. was isolated from milk of serologically nonreactive buffaloes. PMID:19046520

  14. Detection of Strawberry Viruses in Egypt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of a USAID-MERC funded project, ‘Disease-indexing and mass propagation of superior strawberry cultivars’, an effort was made to evaluate the virus status of strawberries in Egypt. Diagnostic reverse transcription-polymerase chain reaction (RT-PCR) tests for Strawberry mottle, Strawberry cri...

  15. Censorship and Security Agents Pervade Egypt's Universities

    ERIC Educational Resources Information Center

    Mills, Andrew

    2008-01-01

    This article offers a glimpse into one of the many ways in which the Egyptian government and the campus administrators it appoints are slowly and persistently squeezing the life out of universities in Cairo, Egypt. Classroom discussions are monitored, faculty appointments and academic research are scrutinized, and faculty participation in outside…

  16. Journey to Egypt: A Board Game

    ERIC Educational Resources Information Center

    Selvidge, Ellen

    2006-01-01

    This author describes how her elementary students first became interested in studying ancient Egypt. Her students' interest in the ancient Egyptian studies began when a student checked out a library book on Egyptology that contained colorful images and was soon swarmed by interested classmates. Many of her students began practicing writing…

  17. Geological and geophysical investigation of Kamil crater, Egypt

    NASA Astrophysics Data System (ADS)

    Urbini, Stefano; Nicolosi, Iacopo; Zeoli, Antonio; El Khrepy, Sami; Lethy, Ahmed; Hafez, Mahfooz; El Gabry, Mohamed; El Barkooky, Ahmed; Barakat, Aly; Gomaa, Mahomoud; Radwan, Ali M.; El Sharkawi, Mohamed; D'Orazio, Massimo; Folco, Luigi

    2012-11-01

    We detail the Kamil crater (Egypt) structure and refine the impact scenario, based on the geological and geophysical data collected during our first expedition in February 2010. Kamil Crater is a model for terrestrial small-scale hypervelocity impact craters. It is an exceptionally well-preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and target rocks comprising subhorizontally layered sandstones. The high depth-to-diameter ratio of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45°. Newly identified asymmetries, including the off-center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well-preserved craters. Geomagnetic data reveal no buried individual impactor masses >100 kg and suggest that the total mass of the buried shrapnel >100 g is approximately 1050-1700 kg. Based on this mass value plus that of shrapnel >10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t.

  18. Modeling Soil Moisture in the Mojave Desert

    USGS Publications Warehouse

    Miller, David M.; Hughson, Debra; Schmidt, Kevin M.

    2008-01-01

    The Mojave Desert is an arid region of southeastern California and parts of Nevada, Arizona, and Utah; the desert occupies more than 25,000 square miles (fig. 1). Ranging from below sea level to over 5,000 feet (1,524 m) in elevation, the Mojave Desert is considered a ?high desert.? On the west and southwest it is bounded by the Sierra Nevada, the San Gabriel, and the San Bernardino Mountains. These imposing mountains intercept moisture traveling inland from the Pacific Ocean, producing arid conditions characterized by extreme fluctuations in daily temperatures, strong seasonal winds, and an average annual precipitation of less than six inches. The Mojave Desert lies farther south and at a lower elevation than the cooler Great Basin Desert and grades southward into the even lower and hotter Sonoran Desert.

  19. Rainbows in the Indian rock art of desert western America.

    PubMed

    Sassen, K

    1991-08-20

    For thousands of years the image of the rainbow was pecked and painted by native Americans onto the rocks of the Great Basin and the Southwest. This long-lived tradition, which transcended major developments in lifestyles and cultures, underscores the important symbolic significance of the rainbow to the inhabitants of this arid region. The rainbow rock art depictions were usually associated with humanlike ceremonial figures, snakes, clouds, rain, and lightning bolts, suggesting that the rainbow symbol was employed as part of an elaborate sacred tradition. Although such ceremonial usage of the rainbow image tends to lead to abstraction and symbolic representation, there are examples, including a properly colorized rainbow painting from central Utah (approximately a thousand years old), that indicate observationally based rainbow reproductions of relatively great antiquity. PMID:20706421

  20. Desert Pathfinder at Work

    NASA Astrophysics Data System (ADS)

    2005-09-01

    The Atacama Pathfinder Experiment (APEX) project celebrates the inauguration of its outstanding 12-m telescope, located on the 5100m high Chajnantor plateau in the Atacama Desert (Chile). The APEX telescope, designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range, passed successfully its Science Verification phase in July, and since then is performing regular science observations. This new front-line facility provides access to the "Cold Universe" with unprecedented sensitivity and image quality. After months of careful efforts to set up the telescope to work at the best possible technical level, those involved in the project are looking with satisfaction at the fruit of their labour: APEX is not only fully operational, it has already provided important scientific results. "The superb sensitivity of our detectors together with the excellence of the site allow fantastic observations that would not be possible with any other telescope in the world," said Karl Menten, Director of the group for Millimeter and Sub-Millimeter Astronomy at the Max-Planck-Institute for Radio Astronomy (MPIfR) and Principal Investigator of the APEX project. ESO PR Photo 30/05 ESO PR Photo 30/05 Sub-Millimetre Image of a Stellar Cradle [Preview - JPEG: 400 x 627 pix - 200k] [Normal - JPEG: 800 x 1254 pix - 503k] [Full Res - JPEG: 1539 x 2413 pix - 1.3M] Caption: ESO PR Photo 30/05 is an image of the giant molecular cloud G327 taken with APEX. More than 5000 spectra were taken in the J=3-2 line of the carbon monoxide molecule (CO), one of the best tracers of molecular clouds, in which star formation takes place. The bright peak in the north of the cloud is an evolved star forming region, where the gas is heated by a cluster of new stars. The most interesting region in the image is totally inconspicuous in CO: the G327 hot core, as seen in methanol contours. It is a truly exceptional source, and is one of the richest sources of emission from complex organic molecules in the

  1. Mortality, Recruitment and Change of Desert Tree Populations in a Hyper-Arid Environment

    PubMed Central

    Andersen, Gidske L.; Krzywinski, Knut

    2007-01-01

    Background Long-term vegetation changes in hyper-arid areas have long been neglected. Mortality, recruitment and change in populations of the ecologically and culturally important and drought persistent Acacia tortilis and Balanites aegyptiaca are therefore estimated in the Eastern Desert of Egypt, and are related to the primary agents of change, water conditions and human intervention. Methodology A change analysis using high-resolution Corona images (1965) in combination with field data (2003) is the basis for recruitment, mortality and change estimates. For assessing the influence of water conditions on patterns in recruitment and survival, different types of generalized linear models are tested. Conclusions The overall trend in population size in that part of the Eastern Desert studied here is negative. At some sites this negative trend is alarming, because the reduction in mature trees is substantial (>50%) at the same time as recruitment is nearly absent. At a few sites there is a positive trend and better recruitment. Frequent observations of sprouting in saplings indicate that this is an important mechanism to increase their persistence. It is the establishment itself that seems to be the main challenge in the recruitment process. There are indications that hydrological variables and surface water in particular can explain some of the observed pattern in mortality, but our results indicate that direct human intervention, i.e., charcoal production, is the main cause of tree mortality in the Eastern Desert. PMID:17299588

  2. Strontium and neodymium isotopic study of Libyan Desert Glass: Inherited Pan-African age signatures and new evidence for target material

    NASA Astrophysics Data System (ADS)

    Schaaf, P.; Müller-Sohnius, D. M.

    2002-04-01

    Libyan Desert Glass (LDG) is an impact-related, natural glass of still unknown target material. We have determined Rb-Sr and Sm-Nd isotopic ratios from seven LDG samples and five associated sandstones from the LDG strewn field in the Great Sand Sea, western Egypt. Planar deformation features were recently detected in quartz from these sandstones. 87Sr/86Sr ratios and e-Nd values for LDG range between 0.71219 and 0.71344, and between -16.6 and -17.8, respectively, and hence are distinct from the less radiogenic 87Sr/86Sr ratios of 0.70910-0.71053 and e-Nd values from -6.9 to -9.6 for the local sandstones from the LDG strewn field. Previously published isotopic ratios from the Libyan BP and Oasis crater sandstones are generally incompatible with our LDG values. LDG formation undoubtedly occurred at 29 Ma, but neither the Rb-Sr nor the Sm-Nd isotopic system were rehomogenised during the impact event, as we can deduce from Pan-African ages of ~540 Ma determined from the regression lines from a total of 14 LDG samples from this work and the literature. Together with similar Sr and Nd isotopic values for LDG and granitoid rocks from northeast Africa west of the Nile, these findings point to a sandy matrix target material for the LDG derived from a Precambrian crystalline basement, ruling out the Cretaceous sandstones of the former "Nubian Group" as possible precursors for LDG.

  3. Mesozoic evolution of the northeast African shelf margin, Libya and Egypt

    SciTech Connect

    Aadland, R.K.; Schamel, S.

    1988-08-01

    The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. Isopach and structural maps, cross sections, and sediment accumulation (geohistory) curves constructed from 89 wells in the Western Desert and 27 wells in northeastern Libya depict the structural and stratigraphic development of the northeast African shelf margin.

  4. Instrumental neutron activation analysis of soil and sediment samples from Siwa Oasis, Egypt

    NASA Astrophysics Data System (ADS)

    Badawy, Wael M.; Ali, Khaled; El-Samman, Hussein M.; Frontasyeva, Marina V.; Gundorina, Svetlana F.; Duliu, Octavian G.

    2015-07-01

    Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

  5. Evaluation of natural radionuclides at Um-Greifat area, eastern desert of Egypt.

    PubMed

    Nada, A

    2003-02-01

    Air borne radiometric maps and remote sensing techniques were used to explore for the occurrence of radioactive materials. The previous techniques recorded radioactive mineralization for the first time along the NW-SE trending fault zones within the Miocene clastic-carbonate sediments. In the present study, gamma-ray spectrometry was used to confirm the presence of this mineralization. Concentrations of radionuclides, associated within the iron ochre at Um-Greifat area, have been measured, using a hyper-pure germanium spectrometer. The variation in concentration of radionuclides for the area under investigation can be classified into A, B and C regions of high, medium and low natural radioactivity. In region A, average concentration in Bqkg(-1) has been observed to range from 1858 to 4062 for 238U, between 29 and 151 for 232Th, from 60 to 136 for 235U and between 46 and 409 Bqkg(-1) for 40K. Radium equivalent activities (Ra(eq)) in addition to external and internal hazard indices (H(ex), H(in)) have also been determined. Ra(eq) varies between 1901 and 4307Bqkg(-1), which exceeds the permitted value (370Bqkg(-1)) and H(ex) and H(in) are higher than 1. The high activity concentration within region A points to an environmental hazard, while regions B and C have less exposure effect on human beings. PMID:12573328

  6. Paleoclimatic and Tectonic History of the Eastern Desert, Egypt and Surroundings

    NASA Technical Reports Server (NTRS)

    Arvidson, Raymond E.

    1997-01-01

    This report covers work for the Planetary Geology and Geophysics Program, which has focused on three areas: analysis of the tectonics and paleoclimatic conditions in north eastern Africa, analysis of surficial geology and damage associated with the 1993 Missouri River floods and rates of lava flow degradation at Lunar Crater volcanic field in Nevada. Work has resulted in several dozen abstracts, several dissertations and a number of papers.

  7. Basement structural control on Cretaceous pull-apart basins of the central Eastern Egypt Desert

    NASA Astrophysics Data System (ADS)

    McCaffrey, K.; El Kazzaz, Y.; Holdsworth, B.

    2006-12-01

    The present-day Red Sea / Gulf of Suez rift system is attributed to extensional block faulting with along-axis segmentation into sub-basins with different dip polarities. The northwestern margin of the Red Sea - Gulf of Suez rift system is exposed for about 400 km along the northwestern Red Sea coast near Quseir to the tip of the Gulf of Suez at Suez City. This area contains elements of the pre-Red Sea structural pattern which has been viewed in similar terms as one of fault-related basin formation. Four distinct depocenters (sub-basins) separated by complex accommodation zones are present containing 500-700m thick section ranging in age from the Late Cretaceous to the Middle Eocene. Each sub-basin is asymmetric, bounded on one side by a major NW-trending border fault system with large throws (3-6 km in general) with a dominant strata dip direction toward the border fault system. These basins are arranged in en echelon patterns and now form separate elongated ridges surrounded by basement rocks. Our study of the tectonic evolution of the central eastern section of the Gulf of Suez rift and the Northwestern Red Sea has focused on the interaction of pre-existing basement fabrics with the pre-Red Sea structural development. The study involved analysis of LandsatTM images and aerial photographs integrated with results from reconnaissance geological mapping. Our provisional results indicate that the Gebel Um Hammad/Duwi and Hammadat sub-basins were sited in pull-apart structures created by dextral reactivation of E-W to ENE-WSW trending basement fault zones. We show how the basin-bounding fault systems, lower order normal faults and folds in both hangingwall sequences and in basement are compatible with a Late Cretaceous to Early Eocene strike-slip regime. In contrast, the main Red Sea Gulf of Suez rift shows no evidence for strike-slip influence with the main boundary faults cutting across basement fabrics, however, as pointed out by previous authors, rift segmentation does appear to be basement-influenced.

  8. Morphological characteristics of interactions between deserts and rivers in northern China

    NASA Astrophysics Data System (ADS)

    Yan, Ping; Li, XiaoMei; Ma, YuFeng; Wu, Wei; Qian, Yao

    2015-12-01

    Arid regions are affected by long-term interactions between various factors including water and wind. Recent research has concentrated on aeolian-fluvial interactions in dryland environments, including the important role of rivers in providing sand and spaces for deserts development, as well as the influences of aeolian activity upon river landforms. However, there is still a lack of comprehensive data at the large watershed scale to support such research. In this study, we analyzed statistically the morphological parameters related to twelve deserts and ten watersheds in dryland regions of northern China using remote sensing data, maps of desert and watershed distributions, and classification of aeolian landforms. Results indicate that, in view of the relationship between deserts and rivers, the geomorphic structures of drainage basins in northern China can be overall divided into five large drainage zones: northwestern drainage (ND), western drainage (WD), drainage of northern Qinghai-Tibet Plateau (PD), middle drainage (MD) and eastern drainage (ED). In the terms of percent area of desert in drainages, it can be sequenced as WD > MD > ND > ED > PD. For percent area of shifting dunes in deserts, WD > PD > MD > ED > ND. Considering the classification of aeolian dunes, transverse dune dominates in all drainages, and its proportion can be sorted as PD > ED > MD > WD > ND. There is a significant difference in their morphological parameters between interior and exterior watersheds. In exterior watersheds, desert area, shifting dune or transverse dune areas are not significantly associated with drainage area respectively, but interior watersheds have good correlations between them. And in three rivers of Tarim Basin, along with increasing distance from the river bank, the types of aeolian dune (complexity) increased step-wisely, implying that sand dune extends along the river terrace. Those data and preliminary findings confirm that the rivers are indispensable to the

  9. Phylogeography of Beck's Desert Scorpion, Paruroctonus becki, reveals Pliocene diversification in the Eastern California Shear Zone and postglacial expansion in the Great Basin Desert.

    PubMed

    Graham, Matthew R; Jaeger, Jef R; Prendini, Lorenzo; Riddle, Brett R

    2013-12-01

    The distribution of Beck's Desert Scorpion, Paruroctonus becki (Gertsch and Allred, 1965), spans the 'warm' Mojave Desert and the western portion of the 'cold' Great Basin Desert. We used genetic analyses and species distribution modeling to test whether P. becki persisted in the Great Basin Desert during the Last Glacial Maximum (LGM), or colonized the area as glacial conditions retreated and the climate warmed. Phylogenetic and network analyses of mitochondrial cytochrome c oxidase 1 (cox1), 16S rDNA, and nuclear internal transcribed spacer (ITS-2) DNA sequences uncovered five geographically-structured groups in P. becki with varying degrees of statistical support. Molecular clock estimates and the geographical arrangement of three of the groups suggested that Pliocene geological events in the tectonically dynamic Eastern California Shear Zone may have driven diversification by vicariance. Diversification was estimated to have continued through the Pleistocene, during which a group endemic to the western Great Basin diverged from a related group in the eastern Mojave Desert and western Colorado Plateau. Demographic and network analyses suggested that P. becki underwent a recent expansion in the Great Basin. According to a landscape interpolation of genetic distances, this expansion appears to have occurred from the northwest, implying that P. becki may have persisted in part of the Great Basin during the LGM. This prediction is supported by species distribution models which suggest that climate was unsuitable throughout most of the Great Basin during the LGM, but that small patches of suitable climate may have remained in areas of the Lahontan Trough. PMID:23933071

  10. Distribution of desert varnish in Arizona

    NASA Technical Reports Server (NTRS)

    Elvidge, Christopher D.

    1989-01-01

    Desert varnish is the dark coat of clay and ferromanganese oxides developed on exposed rock surfaces in arid regions. It forms from the accretion of material from windblown dust. The distribution of desert varnish was mapped in Arizona. It was discovered that desert varnish could be mapped on a regional scale. Well developed desert varnish is common on stable rock surfaces in areas having alkaline soils and less than about 25 cm of annual precipitation. Rock surfaces in areas having more than 40 cm of annual precipitation are generally devoid of desert varnish. An experiment was conducted with varnished desert pavement stone. The stones were broken in half and half was set on a roof in central Illinois from April until October. Removed from the alkaline desert environment, it only took seven months for the varnish to develop an eroded appearance. This experiment graphically illustrates the dependency of desert varnish on alkalinity. In this context, the zones of eroded desert varnish in Arizona indicate that the area of active desert varnish formation has fluctuated, expanding in drier times and contracting/eroding in wetter times.

  11. ESR signal intensity and crystallinity of quartz from Gobi and sandy deserts in East Asia and implication for tracing Asian dust provenance

    NASA Astrophysics Data System (ADS)

    Sun, Youbin; Chen, Hongyun; Tada, Ryuji; Weiss, Dominik; Lin, Min; Toyoda, Shin; Yan, Yan; Isozaki, Yuko

    2013-08-01

    Electron spin resonance (ESR) signal intensity and crystallinity index (CI) of fine- (<16 µm) and coarse-grained (>16 µm) quartz were measured in surface samples from the Taklimakan desert in western China, the Badain Juran, Tengger and Mu Us deserts in northern China, and the Gobi desert in southern Mongolia to evaluate whether these geophysical parameters can serve as reliable provenance tracers of Asian dust. The results indicate that spatial variability of both ESR signal intensity and CI is evident within the Taklimakan deserts and the Mongolian Gobi, but less significant in the three deserts of northern China. Coarse-grained quartz from the Mongolian Gobi and northern China deserts can be differentiated from the Taklimakan desert using the ESR signal intensity. Fine-grained quartz originating from three major Asian dust sources, i.e., the Gobi-sandy deserts in western China, northern China and southern Mongolia, can be distinguished effectively using the combination of ESR and CI signals. Our results suggest that ESR signal intensity and CI can discriminate the sources of fine-grained quartz better than coarse-grained quartz, providing an effective approach to trace the provenance of fine-grained dust deposition on the land and in the ocean.

  12. Spatial and temporal changes in desertification in the southern region of the Tengger Desert from 1973 to 2009

    NASA Astrophysics Data System (ADS)

    Guan, Qingyu; Guan, Wenqian; Yang, Jing; Zhao, Shilei; Pan, Baotian; Wang, Lei; Song, Na; Lu, Min; Li, Fuchun

    2016-04-01

    The sandy land in the southern region of the Tengger Desert is adjacent to cities and towns, and land desertification poses a threat to the livelihood and production of local residents. To determine dynamic changes in local desertification, five periods (1973, 1987, 1992, 2001, and 2009) of remote sensing data are studied by remote sensing (RS) and geographic information system (GIS). The desert contraction area is primarily centered around three units (Wuwei, Gulang, and Jingtai) and nearby regions of Zhongwei City. The primary desert expansion areas include the west side of Helan Mountain (WSHM), the Central Mountainous Area (CMA), and the eastern and western Zhongwei units far from towns. From 1973 to 2009, the degree of change in the contracting part of the primary desert expansion unit showed an increasing trend; in brief, most of the desert (especially after 2001) has been developing in a direction in which desertification has been gradually controlled. The primary desert expansion areas are less affected by human activity, but they are primarily controlled by natural factors (especially wind and terrain). The desert contraction areas occur around the towns and nearby regions with frequent human activity; desertification is primarily controlled by human factors. With rapid economic development (especially after 2000), the scale of the cultivated area, town, and ecological protection engineering has gradually expanded, and the latter two are primarily built on a previous desert, which is the root cause of the reduction in the desert areas around the towns and the shrinkage toward north of border. Therefore, reasonable and effective human activity in the southern region of the Tengger Desert is playing a crucial role in preventing desertification.

  13. Management of Disused Radioactive Sealed Sources in Egypt - 13512

    SciTech Connect

    Mohamed, Y.T.; Hasan, M.A.; Lasheen, Y.F.

    2013-07-01

    The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Egypt depends on the safe and secure management of disused radioactive sealed sources. In the past years have determined the necessity to formulate and apply the integrated management program for radioactive sealed sources to assure harmless and ecological rational management of disused sealed sources in Egypt. The waste management system in Egypt comprises operational and regulatory capabilities. Both of these activities are performed under legislations. The Hot Laboratories and Waste Management Center HLWMC, is considered as a centralized radioactive waste management facility in Egypt by law 7/2010. (authors)

  14. [Our surgical heritage. Surgery in ancient Egypt].

    PubMed

    Oelschlegel, F F; Luther, B; Arnst, C B

    1986-01-01

    In its 3,000 years History the surgery of the Old Egypt came on to an important development. Some of the antique instruments used in traumatology, the general surgery and in cosmetic-plastic operations, are in a scarcely modified manner employed for the same purposes in modern surgical interventions nowadays. The surgical diagnostics and therapy of that time is demonstrated by the surgical instruments stock being in the possession of the "Agyptisches Museum" of the "Staatlichen Museen zu Berlin". The surgery of Egypt transferred its leading part to the prosperous medical schools of Greece at the late period of the Old Egyptian empire (1085-332 B.C.). Its surgical diagnostics and therapy depending on an empirical rationalism, the applied instruments but also its ethical attitude towards the patients have been one of the dedisive bases influencing the development of the surgery in the antiquity. PMID:3532623

  15. [Concepts of the heart in Ancient Egypt].

    PubMed

    Ziskind, Bernard; Halioua, Bruno

    2004-03-01

    The heart was regarded in Ancient Egypt as the organic motor of the body and also the seat of intelligence, an important religious and spiritual symbol. It was considered as one of the eight parts of human body. Counter to other organs it had to be kept carefully intact in the mummy to ensure its eternal life. In Ancient Egypt, the concept of heart included three constituents: heart-haty, heart-ib, and the spiritual seat of intelligence, emotion and memory. The hieroglyphs representing the heart early in the first dynasty were drawn with eight vessels attached to it. Egyptian doctors have elaborated an original conception of cardiovascular physiology which endured 30 centuries. PMID:15067585

  16. Benchmarking performance: Environmental impact statements in Egypt

    SciTech Connect

    Badr, El-Sayed A.; Zahran, Ashraf A.; Cashmore, Matthew

    2011-04-15

    Environmental impact assessment (EIA) was formally introduced in Egypt in 1994. This short paper evaluates 'how well' the EIA process is working in practice in Egypt, by reviewing the quality of 45 environmental impact statements (EISs) produced between 2000 and 2007 for a variety of project types. The Lee and Colley review package was used to assess the quality of the selected EISs. About 69% of the EISs sampled were found to be of a satisfactory quality. An assessment of the performance of different elements of the EIA process indicates that descriptive tasks tend to be performed better than scientific tasks. The quality of core elements of EIA (e.g., impact prediction, significance evaluation, scoping and consideration of alternatives) appears to be particularly problematic. Variables that influence the quality of EISs are identified and a number of broad recommendations are made for improving the effectiveness of the EIA system.

  17. Living donor liver transplantation in Egypt

    PubMed Central

    Marwan, Ibrahim

    2016-01-01

    In Egypt there is no doubt that chronic liver diseases are a major health concern. Hepatitis C virus (HCV) prevalence among the 15−59 years age group is estimated to be 14.7%. The high prevalence of chronic liver diseases has led to increasing numbers of Egyptian patients suffering from end stage liver disease (ESLD), necessitating liver transplantation (LT). We reviewed the evolution of LT in Egypt and the current status. A single center was chosen as an example to review the survival and mortality rates. To date, deceased donor liver transplantation (DDLT) has not been implemented in any program though Egyptian Parliament approved the law in 2010. Living donor liver transplantation (LDLT) seemed to be the only logical choice to save many patients who are in desperate need for LT. By that time, there was increase in number of centers doing LDLT (13 centers) and increase in number of LDLT cases [2,400] with improvement of the results. Donor mortality rate is 1.66 per 1,000 donors; this comprised four donors in the Egyptian series. The exact recipient survival is not accurately known however, and the one-year, three-year and five-year survival were 73.17%, 70.83% and 64.16% respectively in the International Medical Center (IMC) in a series of 145 adult to adult living donor liver transplantation (AALDLT) cases. There was no donor mortality in this series. LDLT are now routinely and successfully performed in Egypt with reasonable donor and recipient outcomes. Organ shortage remains the biggest hurdle facing the increasing need for LT. Although LDLT had reasonable outcomes, it carries considerable risks to healthy donors. For example, it lacks cadaveric back up, and is not feasible for all patients. The initial success in LDLT should drive efforts to increase the people awareness about deceased organ donation in Egypt. PMID:27115003

  18. Living donor liver transplantation in Egypt.

    PubMed

    Amer, Khaled E; Marwan, Ibrahim

    2016-04-01

    In Egypt there is no doubt that chronic liver diseases are a major health concern. Hepatitis C virus (HCV) prevalence among the 15-59 years age group is estimated to be 14.7%. The high prevalence of chronic liver diseases has led to increasing numbers of Egyptian patients suffering from end stage liver disease (ESLD), necessitating liver transplantation (LT). We reviewed the evolution of LT in Egypt and the current status. A single center was chosen as an example to review the survival and mortality rates. To date, deceased donor liver transplantation (DDLT) has not been implemented in any program though Egyptian Parliament approved the law in 2010. Living donor liver transplantation (LDLT) seemed to be the only logical choice to save many patients who are in desperate need for LT. By that time, there was increase in number of centers doing LDLT (13 centers) and increase in number of LDLT cases [2,400] with improvement of the results. Donor mortality rate is 1.66 per 1,000 donors; this comprised four donors in the Egyptian series. The exact recipient survival is not accurately known however, and the one-year, three-year and five-year survival were 73.17%, 70.83% and 64.16% respectively in the International Medical Center (IMC) in a series of 145 adult to adult living donor liver transplantation (AALDLT) cases. There was no donor mortality in this series. LDLT are now routinely and successfully performed in Egypt with reasonable donor and recipient outcomes. Organ shortage remains the biggest hurdle facing the increasing need for LT. Although LDLT had reasonable outcomes, it carries considerable risks to healthy donors. For example, it lacks cadaveric back up, and is not feasible for all patients. The initial success in LDLT should drive efforts to increase the people awareness about deceased organ donation in Egypt. PMID:27115003

  19. First evidence of enterobiasis in ancient Egypt.

    PubMed

    Horne, P D

    2002-10-01

    The oldest and most common parasite for which we have direct evidence, in the New World, is Enterobius vernicularis. Numerous archaeological sites, especially in the arid American southwest, have yielded fecal samples positive for pinworm ova, some of these dating back 10,000 yr. Reports of pinworm from the Old World are scarce. This article reports the first evidence of pinworm infection from Roman-occupied (30 BC-AD 395) Egypt. PMID:12435149

  20. Network topology of the desert rose

    NASA Astrophysics Data System (ADS)

    Hope, Sigmund; Kundu, Sumanta; Roy, Chandreyee; Manna, Subhrangshu; Hansen, Alex

    2015-09-01

    Desert roses are gypsum crystals that consist of intersecting disks. We determine their geometrical structure using computer assisted tomography. By mapping the geometrical structure onto a graph, the topology of the desert rose is analyzed and compared to a model based on diffusion limited aggregation. By comparing the topology, we find that the model gets a number of the features of the real desert rose right, whereas others do not fit so well.

  1. Integrated Human Futures Modeling in Egypt

    SciTech Connect

    Passell, Howard D.; Aamir, Munaf Syed; Bernard, Michael Lewis; Beyeler, Walter E.; Fellner, Karen Marie; Hayden, Nancy Kay; Jeffers, Robert Fredric; Keller, Elizabeth James Kistin; Malczynski, Leonard A.; Mitchell, Michael David; Silver, Emily; Tidwell, Vincent C.; Villa, Daniel; Vugrin, Eric D.; Engelke, Peter; Burrow, Mat; Keith, Bruce

    2016-01-01

    The Integrated Human Futures Project provides a set of analytical and quantitative modeling and simulation tools that help explore the links among human social, economic, and ecological conditions, human resilience, conflict, and peace, and allows users to simulate tradeoffs and consequences associated with different future development and mitigation scenarios. In the current study, we integrate five distinct modeling platforms to simulate the potential risk of social unrest in Egypt resulting from the Grand Ethiopian Renaissance Dam (GERD) on the Blue Nile in Ethiopia. The five platforms simulate hydrology, agriculture, economy, human ecology, and human psychology/behavior, and show how impacts derived from development initiatives in one sector (e.g., hydrology) might ripple through to affect other sectors and how development and security concerns may be triggered across the region. This approach evaluates potential consequences, intended and unintended, associated with strategic policy actions that span the development-security nexus at the national, regional, and international levels. Model results are not intended to provide explicit predictions, but rather to provide system-level insight for policy makers into the dynamics among these interacting sectors, and to demonstrate an approach to evaluating short- and long-term policy trade-offs across different policy domains and stakeholders. The GERD project is critical to government-planned development efforts in Ethiopia but is expected to reduce downstream freshwater availability in the Nile Basin, fueling fears of negative social and economic impacts that could threaten stability and security in Egypt. We tested these hypotheses and came to the following preliminary conclusions. First, the GERD will have an important short-term impact on water availability, food production, and hydropower production in Egypt, depending on the short- term reservoir fill rate. Second, the GERD will have a very small impact on

  2. Capital projects: Egypt case study. Technical report

    SciTech Connect

    Lieberson, J.; Stallard, J.

    1994-03-01

    This report assesses the US Agency for International Development`s (A.I.D.`s) capital assistance program in Egypt in terms of both its commercial benefits for the United States and its developmental benefits for Egypt. In regard to the first aspect, the study found that few A.I.D.-funded projects or studies generated either participation by other donors or follow-on sales for U.S. companies. The report places much of the blame for this on U.S. firms` failure to take advantage of a clear opportunity to develop the Egyptian commercial market. Findings regarding the developmental benefits of the projects are mixed. (1) The projects helped support strong private sector growth in Egypt through the 1980`s. Nonetheless, their economic and financial rates of return were generally disappointing. (2) The projects were built to a high technical standard, but their sustainability is in doubt. (3) The pursuit of commercial advantage for U.S. firms did not distort the developmental goals of the projects. Overall, the report attributes the disappointing economic results of A.I.D.`s capital assistance program to a poor policy environment, which the reforms pursued in connection with the program did little to change.

  3. Lyme borreliosis: A neglected zoonosis in Egypt.

    PubMed

    Elhelw, Rehab A; El-Enbaawy, Mona I; Samir, Ahmed

    2014-12-01

    Borrelia burgdorferi, the causal organism of Lyme borreliosis. In Egypt, available data about the occurrence of Lyme disease are scarce and no structured studies documented the presence of Lyme borreliosis in Egyptian animals and tick reservoirs verifying its zoonotic evidence. Besides, no successful trials to isolate B. burgdorferi from clinical samples have occurred. This study was conducted to investigate B. burgdorferi infection as an emerging zoonosis neglected in Egypt. A total number of 92 animals, tick and human companion specimens were collected and subjected for culture, PCR and/or serodetection. B. burgdorferi has been detected and isolated from Egyptian animal breeds. We also detected the presence of outer surface protein A gene of B. burgdorferi by PCR as well as anti-B. burgdorferi IgM by ELISA in human contacts who were suffering from fever of unknown origin. This report represents the first systematic study on animals associated with patients suffering from febrile illness to confirm the emerging of such neglected zoonosis in Egypt. PMID:25239124

  4. The age of the Taklimakan Desert.

    PubMed

    Sun, Jimin; Liu, Tungsheng

    2006-06-16

    The Taklimakan Desert is located in the foreland basin of the Tibetan Plateau. We report here the results of stratigraphic investigations of a 1626-meter-thick sequence with interbedded wind-blown silt from the southern marginal Taklimakan Desert. Because the studied section is located downwind of the desert, the eolian silt accumulation is closely linked to desert formation. Our new evidence indicates that shifting sand dunes prevailed in the Tarim Basin by at least 5.3 million years ago, as they do today. We attribute this event to late Cenozoic climatic deterioration, as well as to changes in atmospheric circulation induced by Tibetan Plateau uplift. PMID:16778048

  5. Radiation, multiple dispersal and parallelism in the skinks, Chalcides and Sphenops (Squamata: Scincidae), with comments on Scincus and Scincopus and the age of the Sahara Desert.

    PubMed

    Carranza, S; Arnold, E N; Geniez, Ph; Roca, J; Mateo, J A

    2008-03-01

    Phylogenetic analysis using up to 1325 base pairs of mitochondrial DNA from 179 specimens and 30 species of Chalcides, Sphenops, Eumeces, Scincopus and Scincus indicates that Sphenops arose twice independently within Chalcides. It is consequently synonymized with that genus. Chalcides in this broader sense originated in Morocco, diversifying into four main clades about 10 Ma, after which some of its lineages dispersed widely to cover an area 40 times as large. Two separate lineages invaded the Canary Islands and at least five main lineages colonized southern Europe. At least five more spread across northern Africa, one extending into southwest Asia. Elongate bodies with reduced limbs have evolved at least four times in Chalcides, mesic 'grass-swimmers' being produced in one case and extensive adaptation to life in loose desert sand in two others. In clade, Chalcides striatus colonized SW Europe from NW Africa 2.6 Ma and C. chalcides mainland Italy 1.4 Ma, both invasions being across water, while C. c. vittatus reached Sardinia more recently, perhaps anthropogenically, and C. guentheri spread 1200km further east to Israel. C. minutus is a composite, with individuals from the type locality forming a long independent lineage and the remaining ones investigated being most closely related to C. mertensi. In the Northern clade, C. boulengeri and C. sepsoides spread east through sandy habitats north of the Sahara about 5 Ma, the latter reaching Egypt. C. bedriagai invaded Spain around the same time, perhaps during the Messinian period when the Mediterranean was dry, and shows considerable diversification. Although it is currently recognized as one species, the C. ocellatus clade exhibits as much phylogenetic depth as the other main clades of Chalcides, having at least six main lineages. These have independently invaded Malta and Sardinia from Tunisia and also southwest Arabia C. o. humilis appears to have spread over 4000 km through the Sahel, south of the Sahara quite

  6. Power and Gender in Ancient Egypt: The Case of Hatshepsut

    ERIC Educational Resources Information Center

    Hilliard, Kristina; Wurtzel, Kate

    2009-01-01

    Hatshepsut (1479-1458 B.C.E) ruled New Kingdom Egypt for roughly 20 years as one of the few female pharaohs in the history of ancient Egypt. Her rule began when her husband died and her stepson was too young to be pharaoh. To legitimize her role as pharaoh, Hatshepsut began a significant building campaign by constructing numerous images, temples,…

  7. Separate but Equal: Segregated Religious Education in Egypt's Public Schools

    ERIC Educational Resources Information Center

    Isaac, John

    2012-01-01

    The Arab Spring exposed the hidden secrets of Egyptian society to the global community. In spite of the insatiable media attention paid to the Mubarak regime and the toll it took on the entire country, Egypt's education system received little attention. For decades, Egypt's public schools have forced students to attend segregated classes, based on…

  8. A SURVEY OF CYST NEMATODES (HETERODERA SPP.) IN NORTHERN EGYPT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information concerning the occurrence and distribution of cyst nematodes (Heterodera spp.) in Egypt is important to assess their potential to cause economic damage to crop plants. A nematode survey was conducted in Alexandria and El-Behera Governorates in northern Egypt to identify the species of cy...

  9. 77 FR 71777 - Trade Mission to Egypt and Kuwait

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... Trade Mission to Egypt and Kuwait March 10-14, 2013, published at 77 FR 33439, June 6, 2012 to revise... Mission to Egypt and Kuwait March 10-14, 2013, published at 77 FR 33439, June 6, 2012. Due to the... is needed to allow for additional recruitment and marketing in support of the mission....

  10. 75 FR 58353 - Business Development Mission to Egypt and Morocco

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-24

    ... International Trade Administration Business Development Mission to Egypt and Morocco Mission Description The U.S... Business Development Mission to explore ports and infrastructure development opportunities in Egypt (Cairo... infrastructure development with 46 different projects valued at over $16 billion. The majority of these...

  11. Tech Talk for Social Studies Teachers: Ancient Egypt.

    ERIC Educational Resources Information Center

    Pahl, Ronald H.

    1998-01-01

    Presents an annotated bibliography of 10 Web sites concerning ancient Egypt that have materials appropriate for social studies classes. Includes virtual tours of Egypt and specific temples, explorations of the pyramids, archaeological and geographic information, and information on the Egyptian "Book of the Dead." (MJP)

  12. Integrate the Arts. The Art of Ancient Egypt.

    ERIC Educational Resources Information Center

    Parks, Mary

    1996-01-01

    Presents three art projects that can bring to life the study of ancient Egypt for elementary students. After researching Egypt's history and culture, students can create King Tut masks, make Cleopatra headdresses, and craft cartouche pendants. The article describes the materials needed and steps required to complete each project. (SM)

  13. Resource Unit on Egypt for the Intermediate Grades.

    ERIC Educational Resources Information Center

    Husbands, Kenneth; Taylor, Bob

    Resources for teaching about modern and ancient Egypt are provided in this guide for intermediate grade social studies teachers. Material includes: a detailed outline for a unit on Egypt which contains a geographic overview followed by sections on the Nile River Valley, agriculture, the pharaohs, religion, architecture, science, hieroglyphics,…

  14. 78 FR 14979 - Trade Mission to Egypt and Kuwait

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... Trade Mission to Egypt April 14-16, 2013, published at 78 FR 7752, February 4, 2013. The effect of this... participation in the U.S. Trade Mission to Egypt and Kuwait March 10-14, 2013, published at 77 FR 33439, June 6, 2012. In 77 FR 71777, December 4, 2012, the Department of Commerce announced that the...

  15. Student Academic Freedom in Egypt: Perceptions of University Education Students

    ERIC Educational Resources Information Center

    Zain-Al-Dien, Muhammad M.

    2016-01-01

    The purpose of the present study was to investigate student academic freedom from the university education students' point of view in Egypt. This study adopted a survey research design in which the questionnaire was the main data collection instrument. The study participants comprised 800 university education students in Egypt. The result of the…

  16. Sea Breezes over the Red Sea: Affect of topography and interaction with Desert Convective Boundary Layer

    NASA Astrophysics Data System (ADS)

    Khan, Basit A.; Stenchikov, Georgiy; Abualnaja, Yasser

    2014-05-01

    Thermodynamic structure of sea-breeze, its interaction with coastal mountains, desert plateau and desert convective boundary layer have been investigated in the middle region of the Red Sea around 25°N, at the Western coast of Saudi Arabia. Sea and land breeze is a common meteorological phenomenon in most of the coastal regions around the world. Sea-Breeze effects the local meteorology and cause changes in wind speed, direction, cloud cover and sometimes precipitation. The occurrence of sea-breeze, its intensity and landward propagation are important for wind energy resource assessment, load forecasting for existing wind farms, air pollution, marine and aviation applications. The thermally induced mesoscale circulation of sea breeze modifies the desert Planetary Boundary Layer (PBL) by forming Convective Internal Boundary Layer (CIBL), and propagates inland as a density current. The leading edge of the denser marine air rapidly moves inland undercutting the hot and dry desert air mass. The warm air lifts up along the frontal boundary and if contains enough moisture a band of clouds is formed along the sea breeze front (SBF). This study focuses on the thermodynamic structure of sea-breeze as it propagates over coastal rocky mountain range of Al-Sarawat, east of the Red Sea coast, and the desert plateau across the mountain range. Additional effects of topographical gaps such as Tokar gap on the dynamics of sea-land breezes have also been discussed. Interaction of SBF with the desert convective boundary layer provide extra lifting that could further enhance the convective instability along the frontal boundary. This study provides a detailed analysis of the thermodynamics of interaction of the SBF and convective internal boundary layer over the desert. Observational data from a buoy and meteorological stations have been utilized while The Advanced Research WRF (ARW) modeling system has been employed in real and 2D idealized configuration.

  17. Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors

    USGS Publications Warehouse

    Angal, Amit; Chander, Gyanesh; Xiong, Xiaoxiong; Choi, Tae-young; Wu, Aisheng

    2011-01-01

    To provide highly accurate quantitative measurements of the Earth's surface, a comprehensive calibration and validation of the satellite sensors is required. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Characterization Support Team, in collaboration with United States Geological Survey, Earth Resources Observation and Science Center, has previously demonstrated the use of African desert sites to monitor the long-term calibration stability of Terra MODIS and Landsat 7 (L7) Enhanced Thematic Mapper plus (ETM+). The current study focuses on evaluating the suitability of the Sonoran Desert test site for post-launch long-term radiometric calibration as well as cross-calibration purposes. Due to the lack of historical and on-going in situ ground measurements, the Sonoran Desert is not usually used for absolute calibration. An in-depth evaluation (spatial, temporal, and spectral stability) of this site using well calibrated L7 ETM+ measurements and local climatology data has been performed. The Sonoran Desert site produced spatial variability of about 3 to 5% in the reflective solar regions, and the temporal variations of the site after correction for view-geometry impacts were generally around 3%. The results demonstrate that, barring the impacts due to occasional precipitation, the Sonoran Desert site can be effectively used for cross-calibration and long-term stability monitoring of satellite sensors, thus, providing a good test site in the western hemisphere.

  18. Magnetic Analysis Techniques Applied to Desert Varnish

    NASA Technical Reports Server (NTRS)

    Schmidgall, E. R.; Moskowitz, B. M.; Dahlberg, E. D.; Kuhlman, K. R.

    2003-01-01

    Desert varnish is a black or reddish coating commonly found on rock samples from arid regions. Typically, the coating is very thin, less than half a millimeter thick. Previous research has shown that the primary components of desert varnish are silicon oxide clay minerals (60%), manganese and iron oxides (20-30%), and trace amounts of other compounds [1]. Desert varnish is thought to originate when windborne particles containing iron and manganese oxides are deposited onto rock surfaces where manganese oxidizing bacteria concentrate the manganese and form the varnish [4,5]. If desert varnish is indeed biogenic, then the presence of desert varnish on rock surfaces could serve as a biomarker, indicating the presence of microorganisms. This idea has considerable appeal, especially for Martian exploration [6]. Magnetic analysis techniques have not been extensively applied to desert varnish. The only previous magnetic study reported that based on room temperature demagnetization experiments, there were noticeable differences in magnetic properties between a sample of desert varnish and the substrate sandstone [7]. Based upon the results of the demagnetization experiments, the authors concluded that the primary magnetic component of desert varnish was either magnetite (Fe3O4) or maghemite ( Fe2O3).

  19. ECOLOGY OF DESERT SYSTEMS BOOK REVIEW

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 12 chapters of Whitford's book, Ecology of Desert Systems, summarize the comprehensive experiences and knowledge of a scientist with an extensive research background on a wide variety of physical and biological aspects of desert ecology. The author illustrates facts and concepts presented in th...

  20. Notes from the Great American Desert

    ERIC Educational Resources Information Center

    Grady, Marilyn L.; LaCost, Barbara Y.

    2005-01-01

    In the good old days, the state that is Nebraska was identified as part of the Great American Desert. In many ways, in climate and terrain, it still bears a resemblance to a desert. As a frontier or a land of pioneers, it deserves recognition. Invisibility may be one of the greatest challenges women face. One of the great flaws in the writing of…