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1

AEROMYCOBIOTA OF WESTERN DESERT OF EGYPT  

Microsoft Academic Search

The prevalence of airborne mycobiota at six different regions of Western desert (5 regions) and Eastern desert (1) of Egypt was determined using the exposed-plate method. A total of 44 genera, 102 species and one variety in addition to some unidentified yeasts and dark sterile mycelia were collected. Of the above, only 5 species were isolated from the 15 exposures

M. A. Ismail; S. I. I. Abdel-Hafez; A. M. Moharram

2

Groundwater sapping processes, Western Desert, Egypt  

Microsoft Academic Search

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

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

1997-01-01

3

Petroleum potential of Western Desert of Egypt  

SciTech Connect

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.

Wood, D.S.

1984-09-01

4

Western Desert of Egypt: geology and new petroleum exploration concepts  

Microsoft Academic Search

The Western Desert of Egypt has had a sporadic history of exploration. Production has been continuous since the discovery of the Alemein field in 1967, but the emergence of the Gulf of Suez as a giant oil field province has overshadowed Western Desert production. Recent discoveries in the Abu Gharidig subbasin, and better quality seismic data from the basin to

G. Hantar; M. Alloui

1985-01-01

5

Groundwater sapping processes, Western Desert, Egypt.  

SciTech Connect

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-term landform evolution that involves surface and subsurface processes and climatic change.

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

6

Ground-water sapping processes, Western Desert, Egypt  

Microsoft Academic Search

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

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

1997-01-01

7

Sand movement patterns in the Western Desert of Egypt: an environmental concern  

Microsoft Academic Search

Wind action is the most dominant agent for erosion and deposition in the vast Western Desert of Egypt. Analysis of wind data\\u000a from seven meteorological stations distributed along the Western Desert reveals that this desert is characterized by high-energy\\u000a wind environments along the northern and southern edges and low-energy wind environments throughout the rest of the desert.\\u000a Accordingly, sand drift

Mohamed E. Hereher

2010-01-01

8

Ground-water sapping processes, Western Desert, Egypt  

SciTech Connect

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.

Luo, W.; Arvidson, R.E.; Sultan, M.; Becker, R.; Crombie, M.K. [Washington Univ., St. Louis, MO (United States); Sturchio, N. [Argonne National Lab., IL (United States); Alfy, Z.E. [Egyptian Geological Survey and Mining Authority, Cairo (Egypt)

1997-01-01

9

LAND RESOURCES EVALUATION OF THE PALEODARAINAGE DELTA IN WESTERN DESERT OF EGYPT USING REMOTE SENSING DATA  

Microsoft Academic Search

The study area was selected to represent the sediments of paleodrainage delta in the Western Desert of Egypt, covering about 15615653 feddans (6561199 hectars). The data of Landsat Enhanced Thematic Mapper (ETM) 2002 were used for delineating the physiographic units to be a base for the soil taxonomic units (all are hyperthermic). These taxonomic units were potentially evaluated for barley

A. A. Afify

10

Mid-Pleistocene palaeolakes of the Western Desert of Egypt: Palaeoclimate records, palaeoenvironments, and implications  

Microsoft Academic Search

The occurrence of lacustrine carbonates in the Western Desert of Egypt forms one line of evidence for pluvial phases in the Eastern Sahara during the Pleistocene. The study of palaeolake sediments at Kharga and Dakhleh Oasis has yielded information on the hydrology and water balance necessary to maintain the bodies of water during pluvial climates. At Wadi Midauwara in the

J. M. Kieniewicz; J. R. Smith

2006-01-01

11

Plant Diversity Around Springs and Wells in Five Oases of the Western Desert, Egypt  

Microsoft Academic Search

This study was conducted to analyse the floristic composition around the wells and springs in five oases (Siwa, Bahariya, Farafra, Dakhla & Kharga) of the Western Desert of Egypt in terms of habitat and species diversity. A total 59 sites were surveyed and distributed as follows: twelve in Siwa, fifteen in Bahariya, twelve in Farafra, eight in Dakhla and twelve

MONIER M. ABD EL-GHANI; AHMED M. FAWZY

12

Some Physiological Adaptations to Drought in Xerohalophytic Plants Inhabiting Two Oases in Western Desert of Egypt  

Microsoft Academic Search

Under natural drought, some physiological parameters were measured in some wild species inhabiting the western desert of Egypt. Seasonal changes of nitrogen metabolites and Na\\/K ratio were detected in the investigated species. Effect of seasons, species, and their interaction played an important role on total free amino acids, soluble proteins and Na\\/K ratio at two oases (Dakhla and Kharga). Species

A M Rayan; K A Farghali

2007-01-01

13

SEDIMENTOLOGICAL AND TECHNICAL STUDIES ON THE MONTMORILLONITIC CLAYS OF ABU TARTUR PLATEAU, WESTERN DESERT, EGYPT  

Microsoft Academic Search

One of the most known sedimentary formation among Egyptian Upper Cretacous rock units is named Duwi Formation (Lower Maastrichtian), an outcrop at the Abu Tartur plateau, Kharga Oasis, Western Desert, Egypt. This formation displays three montmorillonitic clayey layers. The investigations of these sediments provide information on the texture, constituents and type of clay minerals, which helps define and describe their

Kadry N. SEDIEK; Ashraf M. AMER

14

Uranium isotopic study of artesian and pluvial contributions to the Nubian Aquifer, Western Desert, Egypt  

Microsoft Academic Search

The groundwater systems of the Nubian Aquifer beneath six major oases (Baris, Kharga, Dakhla, Farafra, Bahariya, and Siwa) in the Western Desert of Egypt have been studied to establish their sources and mixing volumes using uranium isotopes. One hundred six groundwater samples from different depths of the Nubian Aquifer have been analyzed for uranium content and 234U\\/238U activity ratio (AR).The

A. A. Dabous; J. K. Osmond

2001-01-01

15

Paleohydrology of a Pleistocene Pluvial Lake in the Western Desert of Egypt  

Microsoft Academic Search

Stable isotope and minor element analyses of authigenic calcite silts and gastropods from a small (~3-4 km2) paleolake at Wadi Midauwara in Kharga Oasis provide evidence for the prolonged presence of perennial fresh surface water in the currently hyper-arid Western Desert of Egypt during the ~130 ka pluvial event. While sequential chemical analyses of the freshwater gastropod Melanoides tuberculata provide

J. Kieniewicz; J. R. Smith

2005-01-01

16

New age constraints on the Middle Stone Age occupations of Kharga Oasis, Western Desert, Egypt  

Microsoft Academic Search

Spring-deposited carbonate rocks, or tufas, exposed along the flanks of the Libyan Plateau near Kharga Oasis, Western Desert, Egypt, can provide a directly datable stratigraphic context for Middle Stone Age\\/Middle Paleolithic (MSA\\/MP) archaeological material, if such material can be found in situ within tufa strata. Two such localities (Mata'na Site G and Bulaq Wadi 3 Locus 1) described by Caton-Thompson

Jennifer R. Smith; Alicia L. Hawkins; Yemane Asmerom; Victor Polyak; Robert Giegengack

2007-01-01

17

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

Microsoft Academic Search

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

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

2010-01-01

18

Sedimentology of the fluvial and fluvio-marine facies of the Bahariya Formation (Early Cenomanian), Bahariya Oasis, Western Desert, Egypt  

Microsoft Academic Search

The Lower Cenomanian Bahariya Formation in the Bahariya Oasis, Western Desert, Egypt, was deposited under two coeval environmental conditions. A fully fluvial system occurs in the southern portion of the Bahariya Oasis, including depositional products of meandering and braided streams, and a coeval fluvio-marine setting is dominant to the north. These deposits are organized into four unconformity-bounded depositional sequences, whose

M. A. Khalifa; O. Catuneanu

2008-01-01

19

Maastrichtian to Paleocene depositional environment of the Dakhla Formation, Western Desert, Egypt: sedimentology, mineralogy, and integrated micro- and macrofossil biostratigraphies  

Microsoft Academic Search

Integrated sedimentology, mineralogy, geochemistry, and microfossil and macrofossil biostratigraphies of the Maastrichtian–early Paleocene Dakhla Formation of the Western Desert, Egypt, provide improved age resolution, information on the cyclic nature of sediment deposition, and the reconstruction of depositional environments. Age control based on integrated biostratigraphies of planktic foraminifera, calcareous nannofossils and macrofossils yields the following ages for stratigraphic and lithologic sequences.

A. A. Tantawy; G. Keller; T. Adatte; W. Stinnesbeck; A. Kassab; P. Schulte

2001-01-01

20

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

NASA Astrophysics Data System (ADS)

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.

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

2011-08-01

21

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

Microsoft Academic Search

Measurements of radiochlorine (³⁶Cl), radiogenic noble gases (⁴He and ⁴°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 ³⁶Cl\\/Cl ratios yield apparent residence times from â0.2 to 1.2 x 10⁶ years in the deep (600-1200 m) groundwater (assuming constant Cl) and ⤠0.16

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

2004-01-01

22

Cosmogenic, radiogenic, and stable isotopic constraints on groundwater residence time in the Nubian Aquifer, Western Desert of Egypt  

Microsoft Academic Search

Measurements of radiochlorine (36Cl), radiogenic noble gases (4He and 40Ar), 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 36Cl\\/Cl ratios yield apparent residence times from ?0.2 to 1.2 × 106 years in the deep (600–1200 m) groundwater (assuming constant Cl) and ?0.16 ×

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

2005-01-01

23

Origin of ferricretes in fluvial-marine deposits of the Lower Cenomanian Bahariya Formation, Bahariya Oasis, Western Desert, Egypt  

Microsoft Academic Search

The type section of the Lower Cenomanian Bahariya Formation at Gebel El-Dist (Bahariya Oasis, Western Desert), Egypt, comprises claystones, mudstones, siltstones and sandstones deposited in fluvial-deltaic coastal plain, lagoonal, estuarine and shallow marine environments. The formation is characterized by an abundance of ferruginous sandstones that locally weather to form prominent iron crusts. These centimeter to decimeter-scale ferruginous horizons display a

Lawrence H. Tanner; Mohamed A. Khalifa

2010-01-01

24

New age constraints on the Middle Stone Age occupations of Kharga Oasis, Western Desert, Egypt.  

PubMed

Spring-deposited carbonate rocks, or tufas, exposed along the flanks of the Libyan Plateau near Kharga Oasis, Western Desert, Egypt, can provide a directly datable stratigraphic context for Middle Stone Age/Middle Paleolithic (MSA/MP) archaeological material, if such material can be found in situ within tufa strata. Two such localities (Mata'na Site G and Bulaq Wadi 3 Locus 1) described by Caton-Thompson were revisited and sampled for uranium-series analysis. At Mata'na Site G (KH/MT-02), Middle Stone Age ("Upper Levalloisian") material is underlain by tufa with a uranium-series age of 127.9+/-1.3 ka, and overlain by tufa with an age of 103+/-14 ka. At Bulaq Wadi 3 Locus 1, a uranium-series age of 114.4+/-4.2 ka on tufa capping a small collection of Middle Stone Age artifacts also provides a minimum age constraint on that material. Tufa underlying an MSA workshop (KH/MD-10) indicates that this assemblage, characterized by use of several Levallois reduction methods, was deposited after approximately 124 ka. Furthermore, uranium-series ages averaging approximately 133 ka on a Wadi Midauwara tufa (WME-10) without associated archaeological material suggest that one period of spring flow in the region began during the Marine Isotope Stage 6/5e transition, prior to the warmest portion of the last interglacial period. The dated archaeological material suggests that the distinction that has been identified between Nubian and non-Nubian complexes in the Nile Valley may hold for the Western Desert, although local complexity has yet to be fully described. PMID:17433825

Smith, Jennifer R; Hawkins, Alicia L; Asmerom, Yemane; Polyak, Victor; Giegengack, Robert

2007-02-15

25

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

SciTech Connect

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.

Awad, G.M.

1984-05-01

26

Paleohydrology of a Pleistocene Pluvial Lake in the Western Desert of Egypt  

NASA Astrophysics Data System (ADS)

Stable isotope and minor element analyses of authigenic calcite silts and gastropods from a small (~3-4 km2) paleolake at Wadi Midauwara in Kharga Oasis provide evidence for the prolonged presence of perennial fresh surface water in the currently hyper-arid Western Desert of Egypt during the ~130 ka pluvial event. While sequential chemical analyses of the freshwater gastropod Melanoides tuberculata provide a seasonal record of lake water chemistry, analyses of the silts present an integrated centennial- to millennial-scale archive of longer term climatic shifts. Thus, climatic variation can be examined over a variety of temporal scales. Stable isotope analyses of the low-Mg calcite silts imply precipitation in equilibrium with water isotopically equivalent to `fossil' groundwater at Kharga Oasis (~-11‰SMOW), and with a dissolved inorganic carbon reservoir exhibiting little influence of respired carbon (average: -0.5‰PDB). While about 3‰ and 1.5‰ variability occurs in ?{18O and ?13C}, respectively, the isotopes do not covary, suggesting that the lacustrine environment at Wadi Midauwara may have been a hydrologically open system. This is supported by sequential intra-shell stable isotope and minor element analyses of Melanoides tuberculata. Stable isotope variability in ?18O can be accounted for by seasonal changes in water temperature coupled with minor fluctuations in water salinity. The Mg/Ca and Sr/Ca ratios of calcite from the lacustrine silts both decrease upwards through the stratigraphic profile, and weakly covary with the ?18O values for the silts. Mg/Ca and Sr/Ca ratios likely reflect the residence time of the water in the local limestone aquifer, which is driven principally by the amount of local recharge. Thus the decrease probably indicates a gradual decrease in the residence time of local water in the limestone aquifer, and implies increasing rainfall. Surprisingly, the Ba/Ca values for the silts do not covary with the Mg/Ca and Sr/Ca. Because Ba and Sr behave similarly in karstic systems, and are also incorporated similarly into the calcite lattice, the lack of covariance of Ba/Ca with Mg/Ca and Sr/Ca was unexpected. As barite cements are not uncommon in the sandstones of the Nubian aquifer, the Ba/Ca ratio of lacustrine calcite may actually be recording the relative contribution of Ba-rich Nubian aquifer water to a lake that was principally fed by local (Sr- and Mg-rich) limestone aquifers as well as by surficial drainage from limestone-floored watersheds. Wadi Midauwara, like many other foci of spring activity within the Western Desert, is located along a fault which may have provided for artesian discharge from the Nubian aquifer at relatively high elevations above the oasis floor. The climate of the pluvial events of the Sahara has been hypothesized to have been dominated by the Atlantic monsoon, with possible minor input from the Indian Ocean Monsoon. The apparent presence of perennial fresh water at Midauwara is contrary to what would be expected for ponds, fed only by seasonal rainfall. If the Western Desert during the ~130 ka pluvial event received significant summer and winter rains, similar to modern equatorial Africa, the seasonal variation in rainfall source should have been recorded as substantial variation in the ?18O of lake water, a variation which we do not observe. It is more likely, then, that perennial groundwater inflow derived from springs along the Libyan Plateau escarpment, as well as, perhaps, from the Nubian aquifer, maintained the lake.

Kieniewicz, J.; Smith, J. R.

2005-12-01

27

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

NASA Astrophysics Data System (ADS)

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 ?m in diameter) and chalcedony. The megacrystalline quartz occurs as lenticular and prismatic forms (length: 90 250 ?m; width: 30 90 ?m). The microprobe, petrographic and SEM examinations confirmed the occurrence of gypsum relics (diameter; 2 16 ?m) 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 composition contributed to the formation of the nodules.

El Khoriby, Essam M.

2005-06-01

28

Mid-Pleistocene palaeolakes of the Western Desert of Egypt: Palaeoclimate records, palaeoenvironments, and implications  

NASA Astrophysics Data System (ADS)

The occurrence of lacustrine carbonates in the Western Desert of Egypt forms one line of evidence for pluvial phases in the Eastern Sahara during the Pleistocene. The study of palaeolake sediments at Kharga and Dakhleh Oasis has yielded information on the hydrology and water balance necessary to maintain the bodies of water during pluvial climates. At Wadi Midauwara in the southeast of Kharga Oasis, ~8 m of authigenic calcite silts are found in association with extensive tufa deposits representing at least three separate pluvial phases during the Pleistocene. The silts are probably coeval with MIS 5e, as they are overlain by a tufa unit dated to 126±4 ka and as they are very friable, could not have survived a prolonged period of aridity. Stable isotope and minor element analyses of the silts and the gastropod shells found within them are not consistent with a highly evaporative environment—in fact they suggest that the lake was probably hydrologically open, and remained perennially fresh. The silt geochemistry has also provided insight on the relationships between evaporation and water residence time in local limestone aquifers. Unlike the lake at Wadi Midauwara which probably received its water primarily from spring discharge, the Dakhleh palaeolake was partly supported by Nubian aquifer groundwater discharging at a higher rate than today. Despite this, the lake likely received considerable input from locally recharged water since Nubian aquifer is undersaturated with respect to calcite in Dakhleh Oasis, and the high carbonate content of the marls demands the input of carbonate derived from the nearby Libyan Plateau. Furthermore, the presence of tufa deposits along the escarpment suggests that water derived from the plateau likely contributed to the water budget of the lake. The lake sediments occur as erosional remnants on the southern margins of the Dakhleh basin to the south of the Libyan Plateau, and primarily represent shallow lacustrine facies. ? 18O values of the carbonates are consistent with precipitation from water isotopically heavier than Nubian aquifer water, and the presence of evaporites and a positively covariant trend between ? 18O and ? 13C confirms a more evaporative environment than that at Midauwara.

Kieniewicz, J. M.; Smith, J. R.

2006-12-01

29

RELATIONSHIP BETWEEN PETROLEUM COMPOSITION AND DEPOSITIONAL ENVIRONMENT OF PETROLEUM SOURCE ROCKS FROM THE GULF OF SUEZ AND THE WESTERN DESERT OF EGYPT  

Microsoft Academic Search

Crude oils from the Gulf of Suez and the North Western Desert of Egypt have been analyzed for geochemical biomarkers using GC and GC-MS techniques. The biomarker compositions of the crude oils have been used to differentiate crude oils of non-marine, normal marine and marine carbonate sources. The geochemical features of Zaafarana crude oil from the Gulf of Suez Basin

A. Mostafa; M. Sh. El-Gayar; A. O. Barakat

1998-01-01

30

Airborne ?-ray spectrometric characteristics of lithological units and environmental issues in the Bahariya Oases area in the northern part of western desert, Egypt  

Microsoft Academic Search

Two significant airborne gamma ray spectrometic (AGRS) statistical parameters, i.e., the arithmetic mean and the standard deviation, were computed for all lithologic units and formations of the Bahariya Oases area, Northern Western Desert, Egypt. The results ascertain that the maximum AGRS values are associated with sabkha sediments, Bahariya Formation, basalt flows and sand dunes. The intermediate values are correlated with

Mohamed A. El-Sadek; Ahmed A. Ammar; Mohamed A. Omran; Hatem M. Abu Elkheer

2001-01-01

31

Gardens in the oases of Egypt's Western Desert, and their similarities to ancient Egyptian gardens  

Microsoft Academic Search

IntroductionOases are places with permanent water sources located within vast, dry, surrounding desert landscapes. They can be found in deserts around the globe in a variety of shapes and sizes ranging from very small patches to very linear and long river valleys (e.g. the Nile). Their existence is based on one or more water sources that enable the growth of

Shmuel Burmil

2007-01-01

32

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

PubMed

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 ?Wm(-3) to 2.2 ?Wm(-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 ?Wm(-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

Al-Alfy, I M; Nabih, M A

2012-12-20

33

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

SciTech Connect

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.

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

34

Assessment of waterlogging in agricultural megaprojects in the closed drainage basins of the Western Desert of Egypt  

NASA Astrophysics Data System (ADS)

This paper investigates the development of waterlogging in the cultivated and arable areas within typical dryland closed drainage basins (e.g. the Farafra and Baharia Oases), which are located in the Western Desert of Egypt. Multi-temporal remote sensing data of the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) were collected and processed to detect the land cover changes; cultivations, and the extent of water ponds and seepage channels. The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) has been processed to delineate the catchment morphometrical parameters (i.e. drainage networks, catchment divides and surface areas of different basins) and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The soil of these closed drainage basins is mainly shallow and lithic with high calcium carbonate content; therefore, the downward percolation of excess irrigation water is limited by the development of subsurface hardpan, which also saturates the upper layer of soil with water. The subsurface seepage from the newly cultivated areas in the Farafra Oasis has revealed the pattern of buried alluvial channels, which are waterlogged and outlined by the growth of diagnostic saline shrubs. Furthermore, the courses of these waterlogged channels are coinciding with their counterparts of the SRTM DEM, and the recent satellite images show that the surface playas in the downstream of these channels are partially occupied by water ponds. On the other hand, a large water pond has occupied the main playa and submerged the surrounding fields, as a large area has been cultivated within a relatively small closed drainage basin in the Baharia Oasis. The geomorphology of closed drainage basins has to be considered when planning for a new cultivation in dryland catchments to better control waterlogging hazards. The "dry-drainage" concept can be implemented as the drainage and seepage water can be conveyed through the inactive alluvial channels into certain abandoned playas for evaporation.

El Bastawesy, M.; Ramadan Ali, R.; Faid, A.; El Osta, M.

2013-04-01

35

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

NASA Astrophysics Data System (ADS)

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.

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

2006-07-01

36

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

SciTech Connect

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 Nubian Aquifer has emerged in which lateral flow from a southern recharge area dominates the deep horizons, while shallow horizons contain younger, autochthonous recharge.

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

37

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)

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 found. While some denser (non-porous) tufas are the result of post-depositional infill and alteration of primarily porous tufas, others reflect unaltered, primary fabrics deposited in deep pools or along downstream pool rims. Porous tufas were expected to display substantial evidence of recrystallization, originating at pore margins, but generally showed little to no penetration of diagenetic alteration past the immediate pore boundaries. While general trends in other macroscopic factors were loosely correlated with relative age (e.g., older tufas were paler in color), variation in same-age tufas of different facies is substantial enough to prohibit age classification simply based on these factors. Nicoll, K., Giegengack, R. and Kleindienst, M., 1999. Petrogenesis of Artifact-bearing fossil-spring tufa deposits from Kharga Oasis, Egypt. Geoarchaeology: An International Journal, 14(8): 849-863.

Pohlman, E.; Smith, J. R.

2005-12-01

38

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

Microsoft Academic Search

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

E. Pohlman; J. R. Smith

2005-01-01

39

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

Microsoft Academic Search

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, namely Beris 20, Beris 15, Beris 14, and Beris 13, and

Fakhry A. Assaad

1988-01-01

40

A Study of Hydrogeological Conditions of the Nubian Sandstone Aguifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt.  

NASA Astrophysics Data System (ADS)

A Study of Hydrogeological Conditions of the Nubian Sandstone Aquifer in the Area between Abu Simbel and Toschka, Western Desert, Egypt. By K. A. Dahab*, A. M. Ebraheem**, and E. El Sayed*** *Geology Department, Faculty of Science, Menofia University, Shibin El Kom, Egypt. ** Geology Department, Faculty of Science, Assiut University, Assiut, Egypt. *** Geology Department, Faculty of Science, Minia University, Minia, Egypt. The Nubian Sandstone Aquifer in the area between Toschka and Abu Simbil is small portion of the very well known Nubian Sandstone Aquifer System in the Eastern Sahara, which covers the entire area of southwest Egypt, southeast Libya, northeast Chad, and northern Sudan. Toscha area is currently the site of intensive drilling and development for a huge land reclamation project. The drilling information was used to study the hydrogeological setting of the Nubian Sandstone aquifer in the area. The obtained results indicate that the lithological characteristics and tectonic setting is strongly affecting the groundwater flow pattern as well as the aquifer potentiality of the nubian sandstone aquifer in the area. The aquifer potentiality in this area is low if compared to that of east Oweinat or Dakhla areas. The aquifer is mainly composed of hard ferruginous sandstone with great shale and clay intercalation with a thickness ranging from 140 to 230 meters. Groundwater in this aquifer belongs to fresh to slightly brackish type (salinity is ranging from 240 to 1300 ppm). Ion dominance ordering reveals that sodium cation is mostly predominating over calcium and magnesium whereas chloride is predominant over sulfate and bicarbonate. The groundwater is related to meteoric origin. The high concentration of sodium, chloride, and sulfates reflect leaching and dissolution processes of gypsiferous shales and clay as well as long residence time of water.

Dahab, K. A.; Ebraheem, A. M.; El Sayed, E. A.

2001-05-01

41

The offshore to backshore environments of the Abu Ballas Formation of the SE Dakhla Basin (Western Desert, Egypt)  

Microsoft Academic Search

Zusammenfassung  Die Abu Balks-Formation in der Western Desert Ägyptens stellt eine marine Einschaltung innerhalb von fluviatilen Sandsteinen Nubischen Typs dar. Diese Schichtenfolge dokumentiert eine weitflächige, nach Süden hin in das Dakhla-Becken vorgreifende Transgression aptischen Alters. Im Verlauf dieses ersten Vorstoßes der Tethys während der Kreide wurden im SE des Beckens Sedimente offen und randlich mariner Provenienz abgelagert.Die Ablagerungen der offen marinen

Frits Hendriks; Heinrich Kallenbach

1986-01-01

42

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

Microsoft Academic Search

The New Valley Project has been given much attention in the past 20 years especially from the hydrogeological point of view\\u000a concerning groundwater utilization for the reclamation of a large area of the Western Desert. Lithological, petrophysical,\\u000a and petrographical studies were conducted on four wells south of Beris Oasis, namely Beris 20, Beris 15, Beris 14, and Beris\\u000a 13, and

Fakhry A. Assaad

1988-01-01

43

Age of the Dakhleh impact event and implications for Middle Stone Age archeology in the Western Desert of Egypt  

NASA Astrophysics Data System (ADS)

Dakhleh Glass comprises a suite of chemically distinctive and heterogeneous glassy rocks that occur over an area of ca. 400 km 2 in and around the Dakhleh Oasis in central western Egypt. Previous studies establish a meteorite impact origin for the Dakhleh Glass. No impact crater has yet been found, suggesting an airburst origin. The Dakhleh Glass-forming impact event occurred during the Middle Stone Age time of occupation, but the timing of this event has not been well established. 40Ar/ 39Ar incremental heating of three aliquots from a sample of Dakhleh Glass yield data that can be ascribed to quenched glass which efficiently purged radiogenic 40Ar inherited from the target rocks. One of the aliquots yielded data suggestive of an undegassed clast of target material, but these are easily resolved. The age of the impact event is determined from a compositionally filtered subset of the data that yield an isochron age of 145 ± 19 ka.

Renne, Paul R.; Schwarcz, Henry P.; Kleindienst, Maxine R.; Osinski, Gordon R.; Donovan, John J.

2010-03-01

44

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

SciTech Connect

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.

Assaad, F.A. (P.E. LaMoreaux and Associates, Tuscaloosa, AL (United States))

1988-12-01

45

Mineral evolution and processes of ferruginous microbialite accretion - an example from the Middle Eocene stromatolitic and ooidal ironstones of the Bahariya Depression, Western Desert, Egypt.  

PubMed

Peritidal ferruginous microbialites form the main bulk of the Middle Eocene ironstone deposits of the Bahariya Depression, Western Desert, Egypt. They include ferruginous stromatolites and microbially coated grains (ferruginous oncoids and ooids). Their internal structures reveal repeated cycles of microbial and Fe oxyhydroxide laminae. The microbial laminae consist of fossilised neutrophilic filamentous iron-oxidising bacteria. These bacteria oxidised the Fe(II)-rich acidic groundwater upon meeting the marine water at an approximately neutral pH. The iron oxyhydroxide laminae were initially precipitated as amorphous iron oxhydroxides and subsequently recrystallised into nanocrystalline goethite during early diagenesis. Organic remains such as proteinaceous compounds, lipids, carbohydrates and carotenoids are preserved and can be identified by Raman spectroscopy. The ferruginous microbialites were subjected to post-depositional subaerial weathering associated with sea-level retreat and subsurface alteration by continued ascent of the Fe(II)-rich acidic groundwater. At this stage, another iron-oxidising bacterial generation prevailed in the acidic environment. The acidity of the groundwater was caused by oxidation of pyrite in the underlying Cenomanian Bahariya formation. The positive iron isotopic ratios and presence of ferrous and ferric iron sulphates may result from partial iron oxidation along the redox boundary in an oxygen-depleted environment. PMID:23113844

Salama, W; El Aref, M M; Gaupp, R

2012-11-01

46

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

NASA Astrophysics Data System (ADS)

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, namely Beris 20, Beris 15, Beris 14, and Beris 13, and are defined by latitudes 24°25'E and 24°35'E and longitudes 30°30'N and 30°46'N. The Nubian sedimentation is of Posttectonic deposition that took place over the uplifted Precambrian granitic basement and is Lower Cretaceous, whereas the upper most variegated shales of the cap rock are Upper Cretaceous. 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. Lithologic logs were interpreted together with the electric and micro-logs for adjustment of the shale breaks and showed that there are five water-bearing zones, named from bottom to top: A, B, C, D, and E, and are mainly unfossiliferous orthoquartzites, separated from each other by impervious beds of siltstones, shales, and clays of varying thicknesses. This zoning had been found valid in other parts of the Kharga Oases and could be applied locally in the Kharga Oases area. Mechanical analysis was performed mainly on 39 samples, of which 18 were core samples and 21 were cuttings, that were raised from four wells dug in the area south of Beris Oasis, Kharga Oases. Porosity and permeability tests were carried out on the 18 core samples only. The implication of these data on the environment of deposition of the Nubia Sandstone is discussed. Petrographic examination of a thin section of the subsurface Nubia sandstones in the South of Beris Oasis showed that the lithified rocks fall 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 diagensis. Rounding of the quartz grains shows that transportation had a minor effect on the grain morphology and favor a fluviatile transporting agent.

Assaad, Fakhry A.

1988-12-01

47

Paleozoic and Mesozoic stratigraphy and oil potential of Western Desert  

Microsoft Academic Search

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.

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

1983-01-01

48

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

NASA Astrophysics Data System (ADS)

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.

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

1983-07-01

49

The uppermost deposits of the stratigraphic succession of the Farafra Depression (Western Desert, Egypt): Evolution to a Post-Eocene continental event  

NASA Astrophysics Data System (ADS)

This paper gives insight into continental sedimentary deposits that occur at the uppermost part of the stratigraphic succession present in the north-eastern sector of the Farafra Depression (Western Desert, Egypt). Using space imagery to complete the field work, the geology of the area has been mapped and the presence of a N-S oriented fault system is documented. The analysis of the morphotectonic features related to this fault system allows reconstructing the structural and sedimentological evolution of the area. The study indicates that the continental deposits were accumulated in alluvial systems that unconformably overlie shale and evaporitic rocks attributable to the Paleocene-Eocene Esna Formation. The deposits of the Esna Formation show soft-sediment deformation features, which include slump associated to dish and pillar sedimentary structures and provide evidence of syndepositional tectonic activity during the sedimentation of this unit. The outcrops are preserved in two areas on separated fault-bounded blocks. Proximal alluvial fan facies crop out in a dowthrown block close to the depression boundary. The proximal facies are made up mostly by polymictic conglomerates which occasionally contain boulders. The conglomerate clasts are mainly quartz, carbonate, anhydrite satin spar vein, mudrock, ironstone and nummulite fossils. The mid-fan facies consist of trough cross-bedded, rippled and cross-laminated quartzarenites with reworked glauconite grains and carbonate rock fragments, interpreted as deposited by distributary streams. The distal alluvial fan deposits consist of sandy marls that evolve toward the top of the sections into root-bioturbated lacustrine limestone beds that are locally silicified. The limestones are biomicrites containing characea, ostracods and gastropods with fenestral porosity.

Sanz-Montero, M. E.; Wanas, H.; Muñoz-García, M. B.; González-Acebrón, L.; López, M. V.

2013-11-01

50

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)

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 ?m-sized) with intracrystalline fibrous microfabric marked by fibers (150-250 ?m long and 10-20 ?m 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 the PFC is assumed in the view of its internal microfabric characteristics (pseudospherulitic and lobate internal growth patterns), and morphological features (ellipsoidal to subglobular appearance), in addition to its slightly negative values of ?13C (-0.51‰ to -2.19‰). The low concentration of Na (0.11-0.20%), Sr (70-110 ppm) and Mn (0.04-0.31%), in addition to the negative values of ?18O (-4.65‰ to -5.96‰) in the PFC reflect its deposition from oxygenated freshwater. In addition, the absence of covariance between ?13C and ?18O values (r = -0.202) of the PFC indicates precipitation in a hydrologically-open, short-lived lake setting. In summary, the PFC is of low-Mg type and formed in a hydrologically-open, short-lived, freshwater lake as a primary precipitate with possible bacterial contribution.

Wanas, H. A.

2012-04-01

51

Qena Valley Evolution, Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Remotely sensed topographic and optical data were used to identify tectonic phenomena in Qena Valley. Using digital elevation model, morphotectonic features were identified. Processing and analysis were carried out by the combined use of: (1) digital elevation model, (2) digital drainage network analysis, (3) optical data analysis, and (4) lineament extraction and analysis. Structural information from other sources, such as geological maps, remotely sensed images and field observations were analyzed with geographic information system techniques. The analysis results reveal that the linear features of Qena Valley controlled by several structural elements have different trends NW-SE, NE-SW and N-S trends. Basement rocks at Qena valley has a major NE-SW trending and the sedimentary rocks are dominated by a NW-SE, NE-SW and N-S trends while, E-W are less abundant. The NE-SW trends at north Eastern Desert Egypt attain to normal faults that reflect extension in NW-SE direction, which is related to strike slip faulting along NW-SE directed Najd fault system. Further, the NE-SW is abundant as joints and fractures seem to have controlled the path of the Nile in Qift - Qena area. The NW-SE direction are abundant in the rock fracture trends (Gulf of Suez or Red Sea) and reflects Neoproterozoic faults have been reactivated in Neogene during rifting events of the Red Sea opening and marked the sedimentary rocks at Qena valley. The results of the lineament density map reveals that Qena valley was originated along one fault that trend like the Gulf of Suez and the range of the Red Sea Hills. This major fault was dissected by several lateral faults are seen well exposed at numerous places within the valley, especially on its eastern side. Both sides of Qena valley have a similar density matching may attain to that this lineaments affected Qena valley during rifting. This rifts it probably happened in Early Miocene associated with Red Sea tectonics. The general southward slope of Qena valley refer to North Qena valley uplifting. This uplift attributes to the continental margins uplift during Red Sea rifting, as a result, a sedimentary cover was removed, and the basement rocks were exposed. Although, the uplift located at the basement (east) but most of north Qena valley subjected to this uplift. The accelerated uplift and volcanism in Neogene time that is occurred all along the Red Sea area, with more uplift at northern margin of the Red Sea rift than farther to the south It's probably this uplift gave Qena valley southward direction and the evidence about the uplift the older rocks are exposed to northward

Abdelkareem, Mohamed

2010-05-01

52

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  

Microsoft Academic Search

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 km2, these silts record the ponding of water derived from springs along the Libyan Plateau escarpment and from surface drainage. The ?18O values of these lacustrine

Johanna M. Kieniewicz; Jennifer R. Smith

2007-01-01

53

Structural and tectonic evolution of El-Faiyum depression, North Western Desert, Egypt based on analysis of Landsat ETM+, and SRTM Data  

Microsoft Academic Search

False color Landsat ETM+ (bands 7, 4, 2 in RGB) and SRTM images of the El-Faiyum depression, Egypt, highlights major NE-SW\\u000a faults and other lineaments trending NW-SE and N-S. Airborne magnetic data reveal some E-W subsurface faults which are not\\u000a recognized on Landsat ETM+ and SRTM images. Ratio images (5\\/7, 3\\/1, 4\\/3) and (5\\/7, 5\\/1, 4) were used for lithological

Timothy M. Kusky; Talaat M. Ramadan; Mahmoud M. Hassaan; Safwat Gabr

2011-01-01

54

Paleozoic and Mesozoic stratigraphy and oil potential of Western Desert  

SciTech Connect

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.

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

1983-03-01

55

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

Microsoft Academic Search

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

M. Sultan; N. C. Sturchio; Y. Abdel Hady; M. El Anbeawy

2000-01-01

56

Structural evolution of the Neoproterozoic Western Allaqi–Heiani suture, southeastern Egypt  

Microsoft Academic Search

The Neoproterozic Allaqi–Heiani suture in southeastern Egypt is the western extension of the Allaqi–Heiani–Onib–Sol Hamed–Yanbu suture that represents one of arc–arc sutures in the Arabian–Nubian Shield. It extends for more than 250km from the N-trending Hamisana Shear Zone in the east to Lake Nasser in the west. It separates the 750-Ma-old Southeastern Desert terrane in the north from the 830–720-Ma-old

Mohamed G. Abdelsalam; Mamdouh M. Abdeen; Hamid M. Dowaidar; Robert J. Stern; Amr A. Abdelghaffar

2003-01-01

57

MODELING POPULATION VIABILITY FOR THE DESERT TORTOISE IN THE WESTERN MOJAVE DESERT1  

Microsoft Academic Search

The desert tortoise is a threatened species living in the deserts of the Amer- ican Southwest. Using size-structured demographic models, we analyzed the status of the tortoise in the Western Mojave desert and evaluated the effectiveness of possible manage- ment measures. Our demographic analyses agree with the trends reported by field censuses in showing rapid population decline. Importantly, simulations that

DANIEL DOAK; PETER KAREIVA

1994-01-01

58

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

PubMed

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

Gomaa, Nasr H

2012-01-14

59

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

PubMed Central

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%).

Gomaa, Nasr H.

2012-01-01

60

The photosynthetic pathway types of some desert plants from India, Saudi Arabia, Egypt, and Iraq  

Microsoft Academic Search

Plants collected from different habitats in the deserts of India, Saudi Arabia, Egypt, and Iraq were screened for their photosynthetic CO2-fixation pathways using d13C and dD values. The analyses comprised 128 species belonging to 108 genera and 46 families. Neither the C4 nor the CAM pathway was prevalent in the plant families analyzed except in Poaceae, where C4 metabolism absolutely

H. Ziegler; K. H. Batanouny; N. Sankhla; O. P. Vyas; W. Stichler

1981-01-01

61

Chemistry of columbite-tantalite minerals in rare metal granitoids, Eastern Desert, Egypt  

Microsoft Academic Search

Paragenetic, textural, and chemical characteristics of columbite-tantalite minerals are examined as steps towards identifying the metallogenetic processes of their host granitoids. Columbite-tantalite-bearing granitoids of the Eastern Desert province of Egypt can be categorized into: (i) metaluminous alkali granites; (ii) peraluminous Li-albite granites; and (iii) metasomatized biotite and\\/or muscovite granite (i.e. apogranites). Columbite of the alkali granite is of FeNb206 composition

H. M. Abdalla; H. A. Helba; F. H. Mohamed

1998-01-01

62

Holocene Paleoecology of the Western Tenere Desert, Niger, Africa  

Microsoft Academic Search

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

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

2007-01-01

63

Geochemistry, petrogenesis and radioactivity of El Hudi I-type younger granites, South Eastern Desert, Egypt  

Microsoft Academic Search

The present study deals with geochemical characteristics and petrogenesis of three younger granite varieties (coarse-grained\\u000a biotite-muscovite granites (CBG), garnetiferous muscovite granites (GMG) and Abu Aggag biotite granites (AAG)) in El-Hudi\\u000a area, east of Aswan, southeastern desert of Egypt. Mineral chemistry and whole rock chemistry data revealed that all granites\\u000a have high SiO2 (70.8-74.7 wt.%), Al2O3 (12.8-14.3 wt.%), Na2O and K2O (>3.2 wt.%) contents

Ashraf Emam; Nasser M. Moghazy; Anas M. El-Sherif

2011-01-01

64

Desert pavement development and landscape stability on the Eastern Libyan Plateau, Egypt  

NASA Astrophysics Data System (ADS)

Desert pavement surfaces of the eastern Libyan Plateau in central Egypt represent a stable landscape preserving Middle and Upper Paleolithic artifacts. Detailed measurements of pavement clasts indicate significant variability in clast size, density, lithology and orientation between pavements, but no spatial relationship among any of these pavement variables over the study area. Pavement characteristics are unrelated to local geomorphic features including slope gradient and aspect, suggesting a desert pavement surface that has developed without significant influence from transporting mechanisms such as overland flow and slope failure. Meridional vertical cracks in surface clasts implicate thermal stresses due to diurnal solar variation as a mechanical weathering process, whereas the presence of a clast-free silty layer within all soil profiles indicates that these are accretionary pavement surfaces that have grown upward over time. The desert pavement in this region has likely developed in situ through mechanical breakdown of surface clasts and desert pedogenesis, indicating long-term stability for this region and minimal taphonomic effects on artifacts > 2 cm in diameter deposited on this surface over the last ca. 100 ka.

Adelsberger, Katherine A.; Smith, Jennifer R.

2009-06-01

65

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

NASA Astrophysics Data System (ADS)

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 in each area and revealing the ore mineralogy and the ore textures, geochemical analyses (including rare earth elements) are to be used in order to determine the tectonic setting and magmatic evolution of the host intrusions, scanning electron microscope, microprobe analysis, stable isotopes and fluid inclusions will serve as a new part of this study in detection of the origin and the physico-chemical conditions (P-T condition) for the gold precipitation, Age dating of the host intrusion and mineralization will be based on K-Ar for dating potassium-bearing minerals in fresh host rocks and hydrothermal mineral phases.

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

2012-04-01

66

Microfacies analysis of foraminifera rich sedimentary rocks from the Desert Plateau, central Egypt.  

NASA Astrophysics Data System (ADS)

Microfacies analysis on some samples from the Thebes Group have been carried on by means of thin sections. The study area is included in the Libyan Desert Plateau (central Egypt) at following coordinates N27° 36'30.58" E29° 44'58.34", near the biggest dune of Egypt, the Ghard Abu Muharik. Because of the round shape of the rocks and the desert patina on the surface they could easily be classified as the so called "Melonstones", which are located more southwards and mainly composed by stromatolites. On the contrary, the investigated samples show a completely different fauna and therefore have been separated from the "Melonstones". Even if shape and size are very similar and the desert patina covers all surfaces the same way the differences are impressive. To investigate the samples, two thin-sections have been prepared and analyzed at the microscope. The observed fauna is composed by: agglutinated benthic foraminifera (e.g., Dictyoconus egypticus), complex larger miliolids (e.g., Pseudolacazina cf. danatae, Fabularia sp.), alveolinids (Alveolina vredenburgi), green algae (Dasycladaceae), echinoids and corals. Because of the presence of symbionts bearing larger benthic foraminifera, which need light to feed photosymbionts, the rock was formed in a shallow water environment. With the abundant rock-building benthic foraminifera and calcareous algae the limestone shows a tendency to the packstone/wackestone facies. Based on the presence of Alveolina vredenburgi, the age of the samples can be estimate as lowermost Eocene belonging to the shallow benthic zone 5 (sensu Serra-Kiel et al., 1998). According the obtained data on stratigraphy and palaeoecology, a partial palaeoenvironmental reconstruction is possible for the Libyan Desert Plateau where outcrops are largely missing. Because of the round shape of the samples and the patina which covers them all around it can be assumed that they have been transported from longer distance. According to the geological map of the area and to the fauna observed in the sections, the source of the samples can be related to the Farafra Formation, which is characterized by white to grey alveolinid shallow water limestone. The closest outcrop belonging to this formation can be found around 50 kilometers westwards from the location where the samples were taken. Serra-Kiel J., Hottinger L., Caus E., Drobne K., Ferrà Ndez C., Jauhria.K., Less G., Pavlovec R., Pignatti J., Samsó J.M., Schaub H., Sirel E., Strougo A., Tambareau Y., Tosquella J., ZAKREVSKAYA E., 1998 - Larger Foraminiferal Biostratigraphy Of The Tethyan Paleocene And Eocene. Bull. Soc. géol. France, 169 (2): 281-299.

Karnitschar, C.; Briguglio, A.; Hohenegger, J.

2012-04-01

67

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

NASA Astrophysics Data System (ADS)

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.

Coogan, James C.; Decelles, Peter G.

1996-10-01

68

Silver and silver-bearing minerals at the Um Samiuki volcanogenic massive sulphide deposit, Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Um Samiuki Zn Cu Pb Ag mineralisation, south Eastern Desert, Egypt is hosted by felsic volcanic rocks which form part of the 712-Ma-old, east-west-trending Shadli Volcanic Belt. Two major occurrences of massive sulphides are present at the top of rhyolitic breccia in the Western and Eastern mine areas. In each occurrence, a bornite-bearing zone is overlain by a pyrite-chalcopyrite-bearing zone and underlain by a disseminated, Cu-depleted zone. In the massive sulphide ore, sphalerite, chalcopyrite, pyrite, galena, bornite and tetrahedrite tennantite are major minerals, whereas arsenopyrite, pyrrhotite, molybdenite and magnetite are accessory phases. Covellite and digenite are common secondary minerals. Bornite, tetrahedrite tennantite and covellite contain high amounts of silver (averages of 1.97, 1.39 and 1.82 wt% respectively). Based on mineralogical balance calculations, bornite and covellite accommodate 80% of silver in the Um Samiuki deposit. Ag was incorporated in the crystal structure of the early-crystallised copper sulphides and sulphosalts and silver minerals. The temperature, sequential precipitation of the fluids and the structure of the crystallising phases control the distribution of silver. Post-depositional deformation and metamorphic processes caused liberation, remobilisation and redeposition of silver within the massive sulphides.

Shalaby, Ibrahim M.; Stumpfl, Eugen; Helmy, Hassan M.; El Mahallawi, Mahmoud M.; Kamel, Omar A.

2004-10-01

69

Springs in Egypt  

NASA Astrophysics Data System (ADS)

Examples of springs in Egypt deal only with examples of natural springs producing potable water. None of the natural springs producing highly mineralized thermal water for therapeutical are considered. No water from natural springs in Egypt is bottled. Egyptian standards state that the total dissolved solids in potable water should not exceed 1000 ppm, except in Siwa, where the only available source for water for human consumption is from springs that have water containing more than 2000 ppm TDS. Six natural springs in Egypt provide typical examples for the Sinai and the Western Desert: Ain Furtaga in the southern pre-Cambrian province of Sinai Peninsula; Ain El Gudeirat in the sedimentary plateau of North Sinai; and Ain El Bishmo, Ain El Bousa, and Ain El Gabal in the Western Desert Oases of Bahariya, Kharga, and Dakhla. They discharge from the Nubian Sandstone aquifer system. The sixth spring, Ain El Arayes, is a spring in Siwa Oasis.

Idris, H.

1996-03-01

70

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

PubMed

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

Dawood, Y H

2001-12-01

71

The Use of the Sustainable Development Multi-Indicators for Evaluating the Stabilization in some new Rural Communities in Desert Areas of Egypt  

Microsoft Academic Search

1. Abstract One of the most important indicators to illustrate the success of the emigration policy in Egypt, is the increase of new rural communities in the Egyptian desert. Accordingly, the population inclination to move from the overpopulated Nile valley to the Egyptian desert increases, developing it, creating more job opportunities and generating income for the individual. The ability of

W. F. ERIAN

72

SWIR ASTER band ratios for lithological mapping and mineral exploration: a case study from El Hudi area, southeastern desert, Egypt  

Microsoft Academic Search

This study aims to discriminate and to map the basement rocks as well as the barite mineralization exposed at El Hudi area,\\u000a Southeastern Desert, Egypt using the processed short-wave infrared bands of advanced space-borne thermal emission and reflection\\u000a radiometer (ASTER) in collaboration with the field verification and petrographic analysis. El Hudi area is covered dominantly\\u000a by the Late Precambrian high-grade

A. A. Madani; A. A. Emam

2011-01-01

73

Study of radioactivity levels in granite of Gable Gattar II in the north eastern desert of Egypt  

Microsoft Academic Search

The present work deals with the radioactivity of granites in Gable Gattar II, which is located in the north eastern desert of Egypt. Fifty samples from the area of Gable Gattar II were investigated. The radionuclides of the samples, in Bq\\/kg, have been measured using a hyper-pure germanium spectrometer. The dose obtained for 238U and 232Th ranged from 165±5 to

A. El-Shershaby

2002-01-01

74

Paleozoic cratonal/miogeoclinal stratigraphy in the western Mojave Desert  

SciTech Connect

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.

Martin, M.W.; Walker, J.D. (Univ. of Kansas, Lawrence (United States))

1991-02-01

75

Technologies Applied in the Toshka Project of Egypt  

ERIC Educational Resources Information Center

|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.…

Wahby, Wafeek S.

2004-01-01

76

Apparent weekly and daily earthquake periodicities in the western United States, and evolution of Wadi Kubbania in Egypt  

NASA Astrophysics Data System (ADS)

The dissertation consists of two separate sections. The first section is on apparent daily and weekly periodicities in earthquake occurrence in the western United State. Analysis of Apparent Seismicity Rate (ASR) in the western United States confirmed the existence of prominent spectral peaks with a period of 1 and 7 days. The number of recorded earthquakes on Sundays for the duration of 1963-2008 is about 5% higher than that on weekdays, and, more significantly, there is a 9% increase of ASR in the early morning compared with that in the middle of the days. Significant similarities between the spatial distributions of the weekly and daily variations suggest that the two types of variations have the same sources and both originate from periodic variations in cultural noise that lead to periodic variations in the detectability of the seismic networks. The second section of the dissertation reports results from an active-source seismic experiment conducted in southern Egypt. The ancient Nile River (pre-Eonile) is believed to have flowed west-northwest from the Red Sea Hills due to the Nubian uplift in the Eastern Desert. It continued over Wadi Abu Subeira in the Eastern Desert and across the modern Nile to the Western Desert over the valley known today as Wadi Kubbania. This study addresses two hypotheses. The first hypothesis advocates that Wadi Kubbania was a morphologically incised valley of the pre-Eonile River where uplift of the Nubian swell may have forced rapid erosion forming Wadi Kubbania. The second hypothesis argues that Wadi Kubbania is a northwest trending graben formatted as a result of regional tectonic effects of the rifting of the Red Sea and the associated uplift in form of graben structure prior to the flowing of the pre-Eonile River. Analysis of seismic refraction data indicated that the Wadi Kubbania formed as a result of tectonic events.

Atef, Ali Hadi

77

Prospecting for the ferromagnetic mineral accumulations using the magnetic method at the Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

In this study we delineate the subsurface structures within an area of about 145 000 km2 in the Central Eastern Desert of Egypt (CED), using magnetic methods. The main goal is to establish the tectonic framework of the study area and to understand the role of tectonics in the mineralization process. Aeromagnetic data covering the study area were used, and also detailed land magnetic surveys were carried out along profiles. More than 300 rock samples were collected for laboratory measurements of magnetic susceptibility. The data set was processed using a series of techniques, namely trend analysis, 3D Euler deconvolution, Werner deconvolution and 2.5 direct modelling. Results indicate that the most predominant tectonic trends are E-W, N15°-25°W and N45°W. The depth to the basement estimates range from the surface to 1.8 km. These results agree with the drilled well data. The measured magnetic susceptibility values range between 0.0001 SI and 5 SI. The high susceptibility values strongly suggest that ferromagnetic minerals accompany the mafic metavolcanics along the shear zones at Barramiya, Hafafit, Dawi and Abu Swayel. We show a good correlation between the structures deduced from the magnetic analysis and the known mineral distributions. Most of these ore accumulations are restricted to the major tectonic shear zones with a NW-SE direction. We conclude that mineralization is structurally controlled by faulting, probably as a result of hydrothermal circulation along fault planes.

Rabeh, Taha

2009-12-01

78

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

PubMed

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

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

79

Geology, petrology and geochronology of the metamorphic rocks of Meatiq Dome, Central Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Meatiq Dome is an antiformal structure exposed in a 500 sq km area in the Late Proterozoic terrane of the Central Eastern Desert of Egypt. The dome consists of a conformable sequence of metamorphic units. In ascending order, these are granite gneiss, quartzofeldpathic mylonite, quartz phyllonite, and mafic mylonite. Syntectonic intrusions of diorite tonalite granodiorite are within the units above the granite gneiss. Post tectonic granite crosscuts all other units. Foliation in the metamorphic units is low angle, and is associated with NW trending lineation, intrafolial folds have axes subparallel to lineation. The granite gneiss consists of two subunits--one (white gneiss) is marginally peralkaline and arfvedsonite bearing, and the other (pink gneiss) is metaluminous and hornblende and biotite bearing. The quartzofeldspathic mylonite is nearly identical in composition to the pink gneiss, compatible with a single granite protolith for these two units. The quartz phyllonite bears strong compositional resemblance to the pink gneiss and quartzofeldspathic mylonite, with the main exception of Na content which is very low in this unit. The chemical data suggest that the quartz phyllonite had a volcanic protolith that had undergone extensive hydrothermal alteration soon after emplacement.

Sturchio, N. C.

80

Distribution and interpretation of radioelements, wadi dib area, north eastern desert, Egypt  

NASA Astrophysics Data System (ADS)

Gamma-ray spectrometric data of the Wadi Dib area, located in the north of the Eastern Desert, Egypt, have been treated qualitatively and quantitatively by applying various techniques. The potential of uraniferous provinces can be fully evaluated through an integrated program in three ways. The first is a statistical treatment of data searching for areas showing high uranium content within each unit. The second route is by examining the stacked profiles for regions of high eU, eU/eTh and eU/K. The third option is by calculating the average uranium, thorium and potassium for each rock unit and comparing these with the published crustal average values. The spectrometric interpretation of the study area shows the locations and magnitudes of the deviations from the mean for eU, eU/eTh and eU/K and visualizes eight groups of statistically high locations. In addition the results of this study indicate that all types of rocks have radioelement average abundance values either below or within the crustal average.

Rabie, Said I.

1994-12-01

81

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

Microsoft Academic Search

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,

Mary Katherine Crombie

1997-01-01

82

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

SciTech Connect

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.

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

2000-10-01

83

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

Microsoft Academic Search

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

Matthew L. Brooks

1999-01-01

84

Abu Hamamid Neoproterozoic Alaskan-type complex, south Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Abu Hamamid (AH) Neoproterozoic (Sm/Nd model age of ˜770 ± 20 Ma) mafic ultramafic intrusion lies along a NE SW fracture zone in the Shadli Metavolcanic Belt, south Eastern Desert, Egypt. AH intrusion is concentrically zoned with cumulate clinopyroxene-bearing dunite core mantled by olivine clinopyroxenite, hornblende clinopyroxenite and hornblende gabbroic rim. The observed crystallization sequence is olivine (+spinel)-clinopyroxene hornblende. Orthopyroxene is an extremely rare phase in the core rocks. Clinopyroxene is Ca-rich diopside and spinel shows wide range of Cr# (38 85) and Fe3+# (22 95) ratios. Olivine ranges from Fo74 to Fo81. The ferromagnesian minerals from the AH intrusion show a consistent decrease in the Mg# of olivine (81 74), clinopyroxene (89 81), and hornblende (87 66) from core to rim. The gradational contact between the different rock types of the AH mafic ultramafic rocks, their cumulate nature, the recognition of small-scale layering together with the systematic modal and compositional variations of rock-forming minerals all point to generation by fractional crystallization from a common parental magma. Petrography and mineral compositional data suggest that the AH complex crystallized from fractionated hydrous tholeiitic magma with no significant crustal contamination. AH intrusion shares many important field, petrographic and mineralogical features with Phanerozoic Alaskan-type intrusions formed above subduction zones, suggesting that the AH rocks formed in a similar tectonic environment. Clinopyroxene and spinel chemistry support the subduction-related (island-arc) tectonic environment of origin for the AH complex. This revives interests in models involving subduction-related (island-arc), and possibly plume-interaction origin for the Shadli Metavolcanic Belt.

Farahat, E. S.; Helmy, H. M.

2006-06-01

85

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

Microsoft Academic Search

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

Omran E. Frihy

2009-01-01

86

Palaeomagnetism of Some Neoproterozoic and Early Paleozoic Igneous Rocks from Sinai Peninsula and South Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

A palaeomagnetic study has been carried out in the Neoproterozoic (older Granitoids) and Early Paleozoic (younger Granitoids) rocks from Sinai Peninsula and Hafafit area in the southeastern desert of Egypt. Nineteen sites comprising 158 samples of granite were collected from Saint Katherina area in south Sinai and Wadi Hafafit area, southeastern desert of Egypt. Rock magnetic properties such as Curie temperature and microscopic observations were carried out for these samples to identify the magnetic carrier; it is found to be magnetite. The samples collected were subjected to stepwise thermal and alternating field treatment. Nine sites of Neoproterozoic granite (590 my) yielded reliable magnetic directions, with analysis of the results using standard principal component and great circle analysis. The mean direction for these sites is D=4.5°, I=53.3°, K=57.7,?95=12.2.The Neoproterozoic granite yield a mean pole at 79.7° N, 55.9° E.The results are compatible with data reported from other Gondwana cratonic areas for this time period.

Saleh, A.; Funaki, M.

2002-12-01

87

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

Microsoft Academic Search

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.

Basem A. Zoheir

2008-01-01

88

Spectral properties of carbonatized ultramafic mantle xenoliths and their host olivine basalts, Jabal Al Maqtal basin, South Eastern Desert, Egypt, using ASD FieldSpec spectroradiometer  

Microsoft Academic Search

Understanding the spectral properties of the carbonatized ultramafic mantle xenoliths and their host olivine basalts exposed at Jabal Al Maqtal strike-slip basin, south Eastern Desert, Egypt using portable ASD FieldSpec is the main task of this article. Field data revealed the presence of ultramafic mantle xenoliths at different stratigraphic levels within Jurassic olivine basalts. Ultramafic mantle xenoliths are recorded within

Ahmed A. Madani

2011-01-01

89

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

Microsoft Academic Search

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

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

2010-01-01

90

A new preferential medium for enumeration and isolation of desert actinomycetes  

Microsoft Academic Search

In order to facilitate the discovery of novel actinomycetes from the Egyptian deserts, which can be useful as new sources\\u000a for bioactive metabolites, different media for enumeration and isolation of desert actinomycetes have been tested. For this\\u000a purpose, 30 soil samples from different six sites representing the Western and Eastern deserts of Egypt were collected. The\\u000a two deserts are considered

Wael N. Hozzein; Mohammed Ibrahim A. Ali; Walaa Rabie

2008-01-01

91

Neoproterozoic ophiolitic peridotites along the Allaqi-Heiani suture, South Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Wadi Allaqi ophiolite along the Egyptian-Sudanese border defines the southernmost ophiolitic assemblage and suture zone in the Eastern Desert. Ophiolite assemblages comprise nappes composed mainly of mafic and ultramafic rocks that were tectonically emplaced and replaced by serpentine and carbonates along shear zones probably due to CO2-metasomatism. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of dismembered ophiolites of the western YOSHGAH suture. Microscopically, they are composed of more than 90 % serpentine minerals with minor opaque minerals, carbonate, brucite and talc. The mineral chemistry and whole-rock chemical data reported here indicate that the serpentinized peridotites formed as highly-depleted mantle residues. They show compositions consistent with formation in a suprasubduction zone environment. They are depleted in Al2O3 and CaO similar to those in fore-arc peridotites. Also, high Cr# (Cr/ (Cr+Al)) in the relict chrome spinels (average ~0.72) indicates that these are residual after extensive partial melting, similar to spinels in modern fore-arc peridotites. Therefore, the studied serpentinites represent fragments of an oceanic lithosphere that formed in a fore-arc environment, which belongs to an ophiolitic mantle sequence formed in a suprasubduction zone.

Azer, M. K.; Samuel, M. D.; Ali, K. A.; Gahlan, H. A.; Stern, R. J.; Ren, M.; Moussa, H. E.

2012-06-01

92

Neoproterozoic ophiolitic peridotites along the Allaqi-Heiani suture, South Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The Wadi Allaqi ophiolite along the Egyptian-Sudanese border defines the southernmost ophiolitic assemblage and suture zone in the Eastern Desert. Ophiolite assemblages comprise nappes composed mainly of mafic and ultramafic rocks that were tectonically emplaced and replaced by serpentine and carbonates along shear zones probably due to CO2-metasomatism. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of dismembered ophiolites of the western YOSHGAH suture. Microscopically, they are composed of more than 90 % serpentine minerals with minor opaque minerals, carbonate, brucite and talc. The mineral chemistry and whole-rock chemical data reported here indicate that the serpentinized peridotites formed as highly-depleted mantle residues. They show compositions consistent with formation in a suprasubduction zone environment. They are depleted in Al2O3 and CaO similar to those in fore-arc peridotites. Also, high Cr# (Cr/ (Cr+Al)) in the relict chrome spinels (average ~0.72) indicates that these are residual after extensive partial melting, similar to spinels in modern fore-arc peridotites. Therefore, the studied serpentinites represent fragments of an oceanic lithosphere that formed in a fore-arc environment, which belongs to an ophiolitic mantle sequence formed in a suprasubduction zone.

Azer, M. K.; Samuel, M. D.; Ali, K. A.; Gahlan, H. A.; Stern, R. J.; Ren, M.; Moussa, H. E.

2013-10-01

93

Economics of seawater RO desalination in the Red Sea region, Egypt. Part 1. A case study  

Microsoft Academic Search

Tackling water shortage issues with desalting of seawater and salty water is common in the desert nations of the Middle East and the Mediterranean. The fast growing development in Egypt has required big movements of investments and people from the Nile Valley towards the east, with the fantastic Red Sea and Sinai coastal zones, and also towards the Western Desert

Azza Hafez; Samir El-Manharawy

2002-01-01

94

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

PubMed

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

El-Taher, A

2010-04-24

95

Study of radioactivity levels in granite of Gable Gattar II in the north eastern desert of Egypt.  

PubMed

The present work deals with the radioactivity of granites in Gable Gattar II, which is located in the north eastern desert of Egypt. Fifty samples from the area of Gable Gattar II were investigated. The radionuclides of the samples, in Bq/kg, have been measured using a hyper-pure germanium spectrometer. The dose obtained for 238U and 232Th ranged from 165 +/- 5 to 27,851 +/- 836 and 71 +/- 2 to 274 +/- 8 Bq/kg, respectively. The dose of 40K only changes slightly. To assess the radiological hazard of the natural radioactivity in the samples, the radium equivalent activity, the absorbed dose rate and the external hazard index were calculated. This study provides a baseline map of radioactivity background levels in the Egyptian environment and will be used as reference information to assess any changes in the radioactive background level due to geological processes. The Gable Gattar granite, from uranium mineralization, has high economic potential. PMID:12137021

El-Shershaby, A

2002-07-01

96

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

Microsoft Academic Search

Although the western-Mediterranean coast of Egypt between Sallum and Alexandria, ~550 km long, has maintained a considerable\\u000a equilibrium throughout history, developers have built traditional protective structures in an effort to form sheltered recreational\\u000a beaches without taking into consideration its geomorphologic characteristics, coastal processes and their harmful impact on\\u000a the coastal environment and human safety. The improper practices in this environmentally valuable

Omran E. Frihy

2009-01-01

97

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

NASA Astrophysics Data System (ADS)

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 high degrees of partial melting were available during subduction and closing of the Mozambique Ocean, and emplaced in a forearc basin. Their equilibrium temperature based on olivine-spinel thermometry ranges from 650 to 780 °C, and their oxygen fugacity is high (?log ƒO2 = 2.3 to 2.8), which is characteristic of mantle-wedge peridotites. The Arais peridotites are affected by secondary processes forming microinclusions inside the dunitic olivine, abundances of carbonates and talc flakes in serpentinites. These microinclusions have been formed by reaction between trapped fluids and host olivine in a closed system. Lizardite and chrysotile, based on Raman analyses, are the main serpentine minerals with lesser antigorite, indicating that serpentines were possibly formed under retrograde metamorphism during exhumation and near the surface at low T (<400 °C).

Khedr, Mohamed Zaki; Arai, Shoji

2012-06-01

98

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

NASA Astrophysics Data System (ADS)

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 high degrees of partial melting were available during subduction and closing of the Mozambique Ocean, and emplaced in a forearc basin. Their equilibrium temperature based on olivine-spinel thermometry ranges from 650 to 780 °C, and their oxygen fugacity is high (?log ƒO2 = 2.3 to 2.8), which is characteristic of mantle-wedge peridotites. The Arais peridotites are affected by secondary processes forming microinclusions inside the dunitic olivine, abundances of carbonates and talc flakes in serpentinites. These microinclusions have been formed by reaction between trapped fluids and host olivine in a closed system. Lizardite and chrysotile, based on Raman analyses, are the main serpentine minerals with lesser antigorite, indicating that serpentines were possibly formed under retrograde metamorphism during exhumation and near the surface at low T (<400 °C).

Khedr, Mohamed Zaki; Arai, Shoji

2013-10-01

99

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

Microsoft Academic Search

The Betam gold deposit, located in the southern Eastern Desert of Egypt, is related to a series of milky quartz veins along\\u000a a NNW-trending shear zone, cutting through pelitic metasedimentary rocks and small masses of pink granite. This shear zone,\\u000a along with a system of discrete shear and fault zones, was developed late in the deformation history of the area.

Basem A. Zoheir

2008-01-01

100

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

Microsoft Academic Search

The Neoproterozoic Atud diamictite in Wadi Kareim and Wadi Mobarak in the Eastern Desert of Egypt and the Nuwaybah formation\\u000a in NW Saudi Arabia consist of poorly sorted, polymictic breccia, with clasts up to 1 m of granitoid, quartz porphyry, quartzite,\\u000a basalt, greywacke, marble, arkose, and microconglomerate in fine-grained matrix. Stratigraphic relations indicate that the\\u000a diamictite was deposited in a marine

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

2010-01-01

101

Biological nitrogen fixation to maximize productivity of intercropped legumes and non?legumes: Ten years of field experimentations in semi?arid deserts of egypt  

Microsoft Academic Search

A number of field trials was executed in semi?arid deserts of Ismailia, Egypt, to experiment growth and productivity of sole or mixed canopies of legumes (soybean, leucaena, sesbania, berseem and grasspea) and non?legumes (corn, Rhodes grass, elephant grass, ryegrass and barley) when inoculated with N2?fixing bacteria (diazotrophs) in presence or absence of N fertilizers. An average estimate of > 20

N. A. Hegazi; M. Fayez

2001-01-01

102

Structural geology, single zircon ages and fluid inclusion studies of the Meatiq metamorphic core complex: Implications for Neoproterozoic tectonics in the Eastern Desert of Egypt  

Microsoft Academic Search

The Meatiq metamorphic core complex (MMCC) formed during the Precambrian as a result of multiple deformation and metamorphism in the Eastern Desert of Egypt. Structural, geochronologic, and fluid inclusion microthermometric analyses reveal a long formation\\/deformation history for the MMCC. This started with the break-up of Rodinia at ca. 800 Ma and continued until Pan-African collision at ca. 580 Ma. Between

J. Loizenbauer; E. Wallbrecher; H. Fritz; P. Neumayr; A. A. Khudeir; U. Kloetzli

2001-01-01

103

Effect of ploughing on plant species abundance and diversity in the northwestern coastal desert of Egypt  

Microsoft Academic Search

This study focuses on the effect of ploughing on plant abundance,vegetation cover, species richness, and taxonomic diversity during the growingseasons (winter and spring) of 1992 and 2000 in the habitat of inland plateau(natural habitat), 21 km south of Mersa-Matrouh (Egypt).Ninety-five species belonging to 27 families were recorded. High percentages oflife-forms and a large number of species were recorded in ploughed

Sania K. Hammouda; Selim Z. Heneidy

2003-01-01

104

Performance of desert black goat under extensive production systems in North Sinai in Egypt  

Microsoft Academic Search

SUMMARY - A production system approach was used to study the performance of desert black goat under semi-arid conditions in North Sinai. A random sample of 19 goat breeders was taken. Least squares analysis of variance was performed using fixed effects linear models for all productive traits to develop the technical coefficients used in the study. Biological criteria were kg

A. M. Ahmed; M. H. Kandil; H. M. El-Shaer; H. R. Metawi

105

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

PubMed

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

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

2011-12-05

106

Mesozoic evolution of northeast African shelf margin, Libya and Egypt  

Microsoft Academic Search

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

R. K. Aadland; S. Schamel

1989-01-01

107

The Cretaceous glauconitic sandstones of Abu Tartur, Egypt  

Microsoft Academic Search

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

Brigitte Pestitschek; Susanne Gier; Mahmoud Essa; Johannes Kurzweil

2010-01-01

108

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

NASA Astrophysics Data System (ADS)

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.

El-Baz, F.; Maxwell, T. A.

109

Some biomedical applications of Balanites aegyptiaca grown naturally in radioactive area, Southeastern Desert, Egypt.  

PubMed

Balanites aegyptiaca is a naturally grown desert plant at some radioactive places in Wadi El-Gemal area, Southeastern Desert. The aim of the present study was to highlight on the B. aegyptiaca species grown naturally at radioactive places in Wadi El-Gemal area (fruit part) on the ability of using the fruit in some biomedical application (glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and diabetes). The investigated plant was collected from different location at Wadi El-Gemal area. The uranium content was determined previously and different concentrations from the fruit with highest uranium content were used to examine the effect of B. aegyptiaca (fruit part) on the glucose, triglycerides, total cholesterol (HDL and LDL-cholesterol) levels using experimental rats. Different analysis techniques were used in order to determine different parameters. The obtained data suggest the beneficial role of B. aegyptiaca fruit as an anti-diabetic and hypo-lipidimic agent. PMID:20226589

Morsy, A M A; Ahmad, I A; Kamel, A M

2010-02-04

110

Late precambrian volcanism at Wadi Allaqi, south Eastern Desert, Egypt: evidence for transitional continental arc/margin environment  

NASA Astrophysics Data System (ADS)

The Dokhan volcanics at Wadi Allaqi, situated in the south Eastern Desert of Egypt, range in composition from basaltic-andesite to dacite. Geochemically, they have a transitional character from low K-tholeiite to calc-alkaline with a relatively high Zr/Y ratio that characterises a continental arc/margin setting. The most basic sample has extremely low Mg# (40) and Ni (55 ppm) values, indicating significant fractionation of olivine and clinopyroxene and that it is not a direct partial melt of the mantle-peridotite. The examined andesites and dacites might have been formed, respectively, via low-pressure fractional crystallisation of basaltic-andesite and andesite melts with about 53% and 35% removal of mostly hornblende and plagioclase with little magnetite and biotite. The enrichment of LILE (supposed to be derived from the subducted slab) and the relative depletion of HFSE (Ta, P and Ti) seem to be inherited from the mantle source. Hence, the examined volcanics are affected by both slab-derived partial melts and aqueous fluids in their generation.

El-Nisr, Said A.

1997-04-01

111

Geology, petrology, and geochemistry of a younger granite pluton, central Eastern Desert of Egypt; importance of mixing  

NASA Astrophysics Data System (ADS)

The Younger Granite pluton that is the main subject of study of this work, is a small epizonal pluton in the central part of the Eastern Desert (C.E.D.) of Egypt. This pluton is a representative example of widespread and abundant shallow intrusions emplaced in northern and northeastern Africa in late Precambrian time. The Younger Granite pluton occupies a central position in the Maetiq Dome, a metamorphic core complex. It was emplaced along foliation planes of the country rocks, mainly gneisses and mylonites. This together with other observations indicate that it is a sill. Samples from the Younger Granite pluton are silica rich (77.2-75.3 wt% SiO2), metaluminous to peraluminous rocks (molar Al2O3/(Na2O + K2O + CaO) = 0.98 - 1.09). Whole rock major element abundances of 21 samples show only small variation in SiO2, Al2O3, Na2O and K2O compared to larger variation for the less abundant major elements such as FeO, TiO2, CaO, MnO and MgO and the trace elements Sc, Cr, Co, Rb, Sr, Zr, La, Ce, Nd, Sm, Tb, Yb, Lu, Ta, Th and U.

Sultan, M. I.

112

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

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

113

Late Quaternary arid\\/humid cycles in the Mojave Desert and western Great Basin of North America  

Microsoft Academic Search

This paper discusses the late Quaternary environmental changes that occurred in the drylands of western North America, with particular emphasis on the aeolian\\/lacustrine record from the Mojave Desert. The Basin and Range Province (which includes the Great Basin and the Mojave, Sonoran and Chihuahuan deserts), the primary physiographic region within the North American arid zone, is characterized by a wide

V. P Tchakerian; N Lancaster

2002-01-01

114

The limited role of localized convective storms in runoff production in the western Negev Desert  

Microsoft Academic Search

High-scale floods in the Negev Desert are usually linked to rains originating from the Red Sea Trough (RST), characterized by high-intensity rainspells. While the effect of the RST storms was assessed in the southern, central and eastern parts of the Negev, almost no information exists as to their possible impact in the western parts of the Negev.Rain characteristics and its

G. J Kidron; K Pick

2000-01-01

115

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

Microsoft Academic Search

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

James W. Ball; J. A. Izbicki

2004-01-01

116

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

PubMed

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

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

2005-08-24

117

Preliminary results of a first record of gold and uranium in marble from Central Eastern Desert, Egypt: a witness for (syn- and post-?) metamorphic mineralization in metasediments  

Microsoft Academic Search

This paper records, for the first time, the mineralization of gold (0.98–2.76 ppm) and uranium (133–640 ppm) in marbles from\\u000a the Arabian-Nubian Shield of the Eastern Desert of Egypt. These auriferous and uraniferous marbles are hosted by sheared and\\u000a altered ophiolitic serpentinized ultramafic rocks of Gebel El-Rukham (ER), Wadi Daghbag (DG), and Wadi Al Barramiyah (BM).\\u000a They occur as massive or banded

M. M. Hamdy; G. A. Aly

2011-01-01

118

Geochemical and K Ar age constraints on the Late Neoproterozoic (?) gneisses at Um Tenassib area, north Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Wadi Um Tenassib metamorphic rocks consist mainly of biotite gneiss and biotite-hornblende gneiss with subordinate intercalations of amphibolite, migmatitic gneiss, and aplitic granite. Biotite-hornblende gneiss, biotite gneiss, and aplitic granite are geochemically characterized and their cooling ages are determined by using the K Ar method on biotite. The Um Tenassib gneisses (UTG) range in composition from quartz diorite/monzodiorite to granodiorite. They were derived from igneous rocks that pertain to calc alkaline and metaluminous to weakly peraluminous affinities and were generated in continental volcanic arc setting. REE patterns of the UTG are moderately fractionated (LaN/LuN = 5.9 7.5) relative to those of the aplitic granite (LaN/LuN = 33). The similarity in the geochemical characteristics and REE patterns of both gneiss types indicate their magmatic consanguinity. Amphiboles of the UTG biotite-hornblende gneisses are mainly hornblende, together with few paragasitic hornblende and edenite. Plagioclase composition is oligoclase to andesine (An21 46) in the biotite-hornblende gneiss, and oligoclase (An11 26) in the biotite gneiss. Mineral chemistry of amphibole and plagioclase indicate that the gneisses were metamorphosed under low- to medium-pressure of 2.6 6.4 kbar and at medium to high temperatures of 660 755 °C. The K Ar biotite cooling ages (seven samples) range from 585 ± 12 Ma to 598 ± 12 Ma for the UTG, except one biotite-hornblende gneiss sample gives age of 577 ± 11 Ma. These ages suggest a latest metamorphic cooling event at ca. 585 600 Ma time span, which is consistent with the proposed cooling ages of ˜600 Ma for the Elat metamorphic rocks [Cosca, M.A., Shimron, A., Caby, R., 1999. Late Precambrian metamorphism and cooling in the Arabian Nubian Shield: petrology and 40Ar/39Ar geochronology of metamorphic rocks of the Elat area (southern Israel). Precamb. Res. 98, 107 127]. It may indicate that the metamorphism of the UTG might have been contemporaneous with the suggested regional metamorphism at 620 ± 10 Ma for Sinai metamorphic rocks (Cosca et al., 1999) and/or the emplacement age at 614 Ma for the granodiorite in the study area [Stern, R.J., Hedge, C.E., 1985. Geochronological and isotopic constraints on the Late Precambrian crustal evolution in the Eastern Desert of Egypt. Am. J. Sci. 285, 97 127]. These ages also lie within the range of magmatic activity of the Younger Granites in the North Eastern Desert (575 600 Ma).

Eliwa, Hassan A.

2007-05-01

119

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

NASA Astrophysics Data System (ADS)

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.

Bhatt, N.

2012-04-01

120

A local-scale groundwater flow model for groundwater resources management in Dakhla Oasis, SW Egypt  

Microsoft Academic Search

Dakhla Oasis is located in the Western Desert of Egypt. Groundwater exploited from the Nubian Sandstone aquifer is the only available water resource in this area. This resource has been heavily exploited since 1960, which has led to a substantial decline in the potentiometric surface of the aquifer. A regional numerical groundwater flow model, calibrated under unsteady-state conditions, has been

A. M. Ebraheem; S. Riad; P. Wycisk; A. M. Sefelnasr

2004-01-01

121

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

NASA Astrophysics Data System (ADS)

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 used in establishing a sustainable shoreline management plan, which is, in turn, an essential part when implementing an Integrated Coastal Zone Management Plan for this region of attraction.

Frihy, Omran E.

2009-09-01

122

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

NASA Astrophysics Data System (ADS)

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.

Asayed El Gammal, El

2010-05-01

123

Oligocene larger foraminifera from United Arab Emirates, Oman and Western Desert of Egypt  

Microsoft Academic Search

An early Oligocene (Rupelian) diagnostic larger foraminiferal assemblage is described and illustrated from marls and limestones of the Asmari Formation, at Jabals Hafit and Malaqet in the UAE. An equivalent assemblage is identified in the mudstones of the Tahwah Formation, Wadi Suq, Oman. Although Nummulites intermedius (D'Archiac 1846) and N. fichteli are fully synonymous (e.g. Roveda 1970; Schaub 1981; Sirel

Mohamed Boukhary; Osman Abdelghany; Yasmine Hussein-Kamel; Salah Bahr; Abdul Razak Alsayigh; Mousheera Abdelraouf

2010-01-01

124

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

PubMed

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

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

2002-09-01

125

Groundwater development, Kharga Oases, Western Desert of Egypt: A long-term environmental concern  

Microsoft Academic Search

The groundwater reserves in Kharga Oases have been studied for the long-term socioeconomic development in the area. The Nubian Sandstone, which consists of a thick sequence of coarse clastic sediments of sandstone, sandy clay interbedded with shale, and clay beds, forms a complex aquifer system. The Nubian Aquifer has been providing water to artesian wells and springs in the Kharga

Philip E. Lamoreaux; Bashir A. Memon; Hussein Idris

1985-01-01

126

Groundwater development, Kharga Oases, Western Desert of Egypt: A long-term environmental concern  

NASA Astrophysics Data System (ADS)

The groundwater reserves in Kharga Oases have been studied for the long-term socioeconomic development in the area. The Nubian Sandstone, which consists of a thick sequence of coarse clastic sediments of sandstone, sandy clay interbedded with shale, and clay beds, forms a complex aquifer system. The Nubian Aquifer has been providing water to artesian wells and springs in the Kharga Oases for several thousand years. Groundwater in the Kharga Oases is withdrawn from springs and shallow and deep artesian wells Nearly all the wells originally flowed, but with the exploitation of ground-water from deep wells for irrigation beginning about 1959. the natural flows declined as more and more closely spaced deep wells were drilled By 1975 many deep wells had ceased to flow The water demand in the area has been met by pumping both shallow and deep wells The total annual extraction from deep wells has fluctuated over the year, however, the annual withdrawal from deep wells has exceeded extraction from shallow wells About 17 billion m3 of water was withdrawn from the combination of shallow and deep wells during the period 1960-1980 The Nubian complex aquifer in the Kharga Oases has a very large groundwater potential that could be exploited and beneficially used for a long-term agricultural development in the area, provided proper well spacing and management are implemented Other major environmental considerations for which precise hydrogeologic data are needed include 1 Determination of the long-term yield available from properly constructed and producing artesian wells that will support a planned migration of population from the overcrowded Nile delta and flood plain areas

Lamoreaux, Philip E.; Memon, Bashir A.; Idris, Hussein

1985-09-01

127

Groundwater development, Kharga Oases, Western Desert of Egypt: A long-term environmental concern  

Microsoft Academic Search

The groundwater reserves in Kharga Oases have been studied for the long-term socioeconomic development in the area. The Nubian\\u000a Sandstone, which consists of a thick sequence of coarse clastic sediments of sandstone, sandy clay interbedded with shale,\\u000a and clay beds, forms a complex aquifer system. The Nubian Aquifer has been providing water to artesian wells and springs in\\u000a the Kharga

Philip E. Lamoreaux; Bashir A. Memon; Hussein Idris

1985-01-01

128

Water movement through a thick unsaturated zone underlying an intermittent stream in the western Mojave Desert, southern California, USA  

Microsoft Academic Search

Previous studies indicated that small amounts of recharge occur as infiltration of intermittent streamflow in washes in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. These washes flow only a few days each year after large storms. To reach the water table, water must pass through an unsaturated zone that is more than 130m thick.

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

2000-01-01

129

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

PubMed

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

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

2007-03-29

130

Population fluctuations and interspecific competition between Tephritid flies attacking fruit crops in the New Valley oases, Egypt  

Microsoft Academic Search

Population fluctuations of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) and the peach fly Bactrocera zonata (Saunders) were monitored with lure trap collections in three provinces in the New Valley oases, Western Desert, Egypt. Results showed marked temporal differences in peak trap catches of the two flies in the selected sites all over the entire studied areas. One annual peak

F. A. Abdel-Galil; M. A. Amro; A. S. H. Abdel-Moniem; Ola O. El-Fandary

2010-01-01

131

POLSKIE TOWARZYSTWO MINERALOGICZNE - PRACE SPECJALNE MINERALOGICAL SOCIETY OF POLAND - SPECIAL PAPERS Zeszyt 26, 2005; Volume 26, 2005 GEOCHEMISTRY AND PETROGENESIS OF NEOPROTEROZOIC GRANITOIDS IN KILKBOB AREA, SOUTHEASTERN DESERT, EGYPT  

Microsoft Academic Search

The granitoids (granodiorite, monzogranite-syenogranite and alkali-feldspar granite) in the Gabal Kilkbob area southeastern Desert of Egypt are calc-alkaline, to weakly alkaline and display most of the chemical characteristics of syn- to late-tectonic I-type granitoids to post-tectonic A-type granitoids. The granodiorite was generated by partial melting from a dioritc source, while the monzogranite-syenogranite and the alkali-feldspar granite were derived by fractional

Fawzy BAKHIT; Gehad SALEH; Adel El-AFANDY

132

Estimation of heat generation by radioactive decay of some phosphate rocks in Egypt.  

PubMed

Radiogenic heat production data for phosphate rocks outcropping on the three main areas Eastern Desert, Western Desert and Nile Valley are presented. They were derived from uranium, thorium and potassium concentration measurements of gamma radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K. A low radioactive heat production rate (0.32+/-0.1 microWm(-3)) was found for Wadi Hegaza, whereas the highest value (19+/-4.1 microWm(-3)) was found for Gabel Anz, Eastern Desert of Egypt. PMID:19186064

Din, Khaled Salahel

2008-11-18

133

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

USGS Publications Warehouse

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).

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

134

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

USGS Publications Warehouse

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 extend to the distal ends of all washes. Where urbanization had concentrated spatially distributed runoff into a small number of fixed channels, enhanced infiltration induced recharging conditions, mobilizing accumulated chloride. Estimated amounts of ground-water recharge from the studied reaches were small. Extrapolating on the basis of drainage areas, the estimated aggregate recharge from small intermittent streams is minor compared to recharge from the Mojave River. Recharge is largely controlled by streamflow availability, which primarily reflects precipitation patterns. Precipitation in the Mojave Desert is strongly controlled by topography. Cool moist air masses from the Pacific Ocean are mostly blocked from entering the desert by the high mountains bordering its southern edge. Storms do, however, readily enter the region through Cajon Pass. These storms generate flow in the Mojave River that often reaches Afton Canyon, more than 150 kilometers downstream. The isotopic composition of ground water reflects the localization of recharge beneath the Mojave River. Similar processes occur near San Gorgonio Pass, 75 kilometers southeast from Cajon Pass along the bounding San Andreas Fault.

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

2007-01-01

135

Saprophytic and keratinophilic fungi isolated from desert and cultivated soils continuously exposed to cement dust particles in Egypt.  

PubMed

Forty soil samples collected from desert (uncultivated) and cultivated soils, exposed continuously to cement dust were screened for their content of saprophytic and keratinophilic fungi using the hair baiting technique and the dilution plate method. Using the hair baiting technique, 21 genera and 31 species were collected from 20 samples of each of desert (15 genera and 21 species) and cultivated (17 genera and 24 species) soils, on Sabouraud's dextrose agar. These included Chrysosporium keratinophilum, C. tropicum, C. indicum, Aspergillus niger, Nectria haematococca, Alternaria alternata, Fusarium oxysporum and Penicillium chrysogenum. Using the dilution plate method, 32 genera and 61 species + 3 varieties were collected from 20 samples of each of desert (29 genera and 53 species + 2 varieties) and cultivated (16 genera and 30 species + 2 varieties) soils, on Sabouraud's dextrose agar. The most common fungi were Aspergillus niger, A. fumigatus, A. japonicus, A. terreus, A. flavus and Penicillium funiculosum. PMID:1325092

Bagy, M M

1992-08-01

136

The Release of Chromium in Aquifers Underlying the Western Mojave Desert  

NASA Astrophysics Data System (ADS)

Recent studies suggest that chromium (Cr) in aquifers underlying the western part of the Mojave Desert may be naturally occurring, resulting from the release of this element from aquifer materials in oxic ground water with pH > 8.0. In order to test this hypothesis, we studied the kinetic release of Cr from aquifer material collected from the Sheep Creek fan near Victorville, CA. Pulverized and untreated aquifer material were incubated in 15mL Falcon tubes with water at three different pH values (2, 7, and 9) for 227 days. Duplicate samples were incubated in a heating bath at temperatures 20oC above ambient, in order to accelerate the kinetics of Cr release. Samples from each tube were collected, filtered through a 0.22 ? m filter, and analyzed using a graphite furnace atomic absorption photospectrometer using EPA Method 7199. Due to the heterogeneity of the aquifer material an accurate measure of Cr release kinetics was not possible; results presented here represent equilibrium values at the end of the incubation period. For untreated aquifer material incubated at ambient temperatures, Cr was found at concentrations of 26.0 ± 8.0 ppb at pH = 2, 5.2 ± 0.6 ppb at pH=7, and 9.1 ± 0.9 ppb at pH=9. As expected, the highest value of Cr was found for the samples incubated at pH=2. Pulverization of the samples resulted in an increase in Cr release by a factor of 1.5, 2.4, and 1.6 at pH values of 2, 7, and 9, respectively. Heating the pulverized samples at pH 7 and 9 resulted in an increase in the concentration of Cr released (by 25% and 9% respectively). However, heating the pulverized sample at pH=2 resulted in an almost 95% decrease in the concentration of released Cr (from 37.8 ppb to 2.2 ppb). The reason for this decrease is not known at this point. Our results indicate that significant concentrations of Cr are released naturally in Western Mojave Desert aquifers under various geochemical conditions. Additional studies are underway to study the kinetic release of Cr in packed columns.

Khachikian, C. S.; Plotkin, C.; Monterrosa, A.; Ramirez, P.

2004-12-01

137

Intramontane basin formation during oblique convergence in the Eastern Desert of Egypt: magmatically versus tectonically induced subsidence  

Microsoft Academic Search

The Neoproterozoic Kareim molasse basin in the Central Eastern Desert occupies an intramontane position and is bound by faults of the crustal-scale Najd Fault System. Basin subsidence and sediment delivery rates were linked with exhumation of adjacent core complexes. Sedimentation dynamics evolved in two steps. (1) Early basin infill was magmatically induced by extraction of magmatic material from the lower

H. Fritz; M Messner

1999-01-01

138

Radioactivity and distribution of U and Th in some granitic masses, wadi El-Saqia area, central eastern desert, Egypt  

Microsoft Academic Search

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

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

1996-01-01

139

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

Microsoft Academic Search

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

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

1996-01-01

140

The cooling history of Silurian to Cretaceous alkaline ring complexes, south Eastern Desert, Egypt, as revealed by fission-track analysis  

NASA Astrophysics Data System (ADS)

Forty fission-track ages of apatite, zircon and sphene, and nine horizontal "confined" track-length distribution patterns in apatite have been used to establish the cooling history of nine Silurian to Late Cretaceous alkaline ring complexes which intrude Precambrian basement in the southern Eastern Desert of Egypt. Zircon or sphene fission-track ages were determined from three complexes for whichK/Ar andRb/Sr ages on the same samples were also available, these ages are concordant and are interpreted as emplacement ages resulting from rapid cooling following high level crustal intrusion into relatively thick volcanic piles. Average apatite ages for each of the eight ring complexes range from 33 to 167 m.y. Track-length distribution patterns for apatites taken together with their ages invite subdivision into two groupings. Those complexes yielding Early Oligocene apparent apatite ages suggest cooling from the total track annealing zone followed by a relatively lengthy residence near the base of the partial annealing zone whereas those with Late Cretaceous ages indicate cooling from a shallower level in the partial annealing zone. Variations in cooling history resulted from differential uplift between fault-bound blocks. One block, that containing the Late Cretaceous Abu Khruq complex, was relatively stable and the different degrees of partial resetting recorded in apatites of this complex are attributed to the thermal effect of localised Tertiary dyke intrusion. Fission-track analysis in combination with geologic data indicates that in the south Eastern Desert of Egypt a phase of uplift commenced in Late Oligocene time and was accompanied by paleogeothermal gradients of ca. 40-50°C/km. Uplift was more pronounced (at least 2-2.5 km) in areas within about 100 km from the present Red Sea coast. This uplift, which is viewed as part of a broader regional tectonism related to the opening of the Red Sea, occurred along a northwest fracture pattern and was controlled by pre-existing lines of weakness in the basement complex.

Omar, G. I.; Kohn, B. P.; Lutz, T. M.; Faul, H.

1987-05-01

141

Numbers, foraging and refuelling of passerine migrants at a stopover site in the western Sahara: diverse strategies to cross a desert  

Microsoft Academic Search

Twice a year, songbirds breeding in the Western Palaearctic cross the largest desert of the world, the Sahara, to reach their\\u000a African winter quarters. Recently, a radar study quantified this migration and demonstrated that almost all passerines cross\\u000a the western Sahara with an intermittent strategy, i.e. they fly during the night and rest during the day. Before crossing\\u000a the desert,

Susanne Jenni-Eiermann; Bettina Almasi; Ivan Maggini; Volker Salewski; Bruno Bruderer; Felix Liechti; Lukas Jenni

142

EVALUATION OF DRINKING GROUNDWATER FOR THE RURAL AREAS ADJACENT TO THE NEARBY DESERT OF GIZA GOVERNORATE OF GREATER CAIRO, EGYPT  

Microsoft Academic Search

The choice of the area under investigation takes into consideration several important aspects: heavily populated villages;\\u000a type of drinking water as groundwater; its situation on the west side of the Nile near the intersection point between the\\u000a Nile and its Delta; its neighborhood to the desert of Giza governorate; and its closeness to highly industrial and agricultural\\u000a activities. The present

M. EMARA; I. SABAGH; A. KOTB; D. HUSSEEN

143

The first occurrence of platinum group minerals (PGM) in a chromite deposit in the Eastern Desert, Egypt  

Microsoft Academic Search

The platinum-group mineralogy (PGM) of the chromitite from Gebel Lawi, in the southeastern desert has been investigated. The most abundant base metal sulfides (BMS) associated with the Lawi chromite are pentlandite, millerite and heazlewoodite. The major platinum-group minerals identified were as follows: laurite (IrOsRu)S2, osmian iridium (OsIr), hollingworthite (RhAsS), tellurian arsenopalladinite (PdTeSbAs), potarite (PdHg) besides cuprian palladian gold (CuPdAu), a

M. A. Elhaddad

1996-01-01

144

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

PubMed

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 ?Sv 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

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

2010-12-04

145

Structural influence on the evolution of the pre-Eonile drainage system of southern Egypt: Insights from magnetotelluric and gravity data  

Microsoft Academic Search

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

Jeff Roden; Mohamed G. Abdelsalam; Estella Atekwana; Gad El-Qady; Elhamy Aly Tarabees

2011-01-01

146

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

USGS Publications Warehouse

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.

Brooks, M.

1999-01-01

147

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

USGS Publications Warehouse

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)

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

1983-01-01

148

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

SciTech Connect

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.

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

1983-01-01

149

Microbiotic crusts and their interrelations with environmental factors in the Gurbantonggut desert, western China  

Microsoft Academic Search

Located in the Junggar Basin in Xinjiang, the Gurbantonggut Desert is the second largest desert in China. Microbiotic crusts consisting of animalcule, lichen, moss, and algae species develop extensively in the region. Their formation, species composition and distribution pattern are closely related to the environmental conditions along the different parts of sand dune. Analysis of microbiotic crust distribution and relationship

Y. N. Chen; Q. Wang; W. H. Li; X. Ruan

2007-01-01

150

GEOGRAPHIC VARIATION OF THE SCREECH OWLS OF THE DESERTS OF WESTERN NORTH AMERICA  

Microsoft Academic Search

Screech Owls (Otus asio) occur widely. across the deserts of the southwestern United States and the northwestern states of Mexico. In these arid regions they range from the oak, and pifion belts of the mountains down through the desert scrub habitat of the lowest basins and river valleys. Mesquite brush, even when well scattered and not more than six feet

ALDEN H. MILLER; LOYE MILLER

151

The first occurrence of platinum group minerals (PGM) in a chromite deposit in the Eastern Desert, Egypt  

Microsoft Academic Search

The platinum-group mineralogy (PGM) of the chromitite from Gebel Lawi, in the southeastern desert has been investigated. The\\u000a most abundant base metal Sulfides (BMS) associated with the Lawi chromite are pentlandite, millerite and heazlewoodite. The\\u000a major platinum-group minerals identified were as follows: laurite (IrOsRu)S2, osmian iridium (OsIr), hollingworthite (RhAsS),\\u000a tellurian arsenopalladinite (PdTeSbAs), polarite (PdHg) besides cuprian palladian gold (CuPdAu), a

M. A. Elhaddad

1996-01-01

152

Radon level and radon effective dose rate determination using SSNTDs in Sannur cave, Eastern desert of Egypt.  

PubMed

For the assessment of inhalation doses due to radon and its progeny to cavern workers and visitors, it is necessary to have information on the time integrated gas concentrations and equilibrium factors. Passive single cup dosimeters using solid state nuclear track detectors (SSNTD) is the best suited for this purpose in wadi Sannur cave, Beni Suef, Egypt. The average radon concentration measurements for the cave are 836 +/- 150 Bq m(-3) by CR-39 detectors and for equilibrium factor an overall average of all measured values was used 0.687. The effective dose for cave workers is 3.65 mSv/year while for visitors is 23 muSv/year. Comparing these values to the Ionizing Radiation Regulations (IRR) values which indicate that the estimated effective doses for workers and visitors in this cave are less than the average overall radon dose. PMID:17906936

Amin, Rafat M; Eissa, M F

2007-09-29

153

Sodium relations in desert plants: 6. Variations in vegetation characteristics along a transect in the Qattara Depression, Egypt  

SciTech Connect

Plants native to the Qattara Depression of Egypt show remarkable zonation in response to changing environmental factors. These factors include: relief, soil texture, soil salt content, relative proportions of ions, and quality of available water. Most species also show considerable selectivity in the absorption of mineral elements. This is indicated by unusually high or low concentrations of specific elements in a species in comparison with concentrations of the same elements in other species growing under similar conditions, and by the fact that a species might have unusually high concentrations of one or several elements, but unusually low contents of other elements. Selective uptake of mineral elements by plants is discussed, taking into account their distributional pattern.

El-Ghonemy, A.A. (Univ. of Tanta); Wallace, A.; El-Gazzar, A.M.; Romney, E.M.

1982-07-01

154

Microbiotic crusts and their interrelations with environmental factors in the Gurbantonggut desert, western China  

Microsoft Academic Search

Located in the Junggar Basin in Xinjiang, the Gurbantonggut Desert is the second largest desert in China. Microbiotic crusts\\u000a consisting of animalcule, lichen, moss, and algae species develop extensively in the region. Their formation, species composition\\u000a and distribution pattern are closely related to the environmental conditions along the different parts of sand dune. Analysis\\u000a of microbiotic crust distribution and relationship

Y. N. Chen; Q. Wang; W. H. Li; X. Ruan

2007-01-01

155

Mesozoic evolution of northeast African shelf margin, Libya and Egypt  

SciTech Connect

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.

Aadland, R.K.; Schamel, S.

1989-03-01

156

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)

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-?m diamonds occur. ?13C 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.

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

157

Using remote sensing technique in lithological discrimination and detection of gold-bearing alteration zones at Wadi Defeit area, southeastern desert, Egypt  

NASA Astrophysics Data System (ADS)

Wadi Defeit area in the extreme South Eastern Desert of Egypt is occupied mainly by Precambrian ophiolitic and island-arc assemblages. The ophiolitic rocks are principally represented by serpentinite, talc-carbonate and listwaenite thrusted over the metasediments and island-arc schistose metavolcanics and intruded by syn to late tectonics intrusions of gabbro-diorite and monzogranite (G2). For discrimination of the basement rock units covering the study area, tracing the major structural features and identification of the mineralized alteration zones, the ETM+ with 7 bands composition and resolution about 15 m was processed where the geometric corrections and radiometric balancing to the image were carried out. The image enhancement techniques including spatial and spectral enhancement, ratioing and stretching have been applied and different band ratios were testes, the band selection for different ratio images used is based on the spectral signatures of these rocks. The study revealed that, based on the spectral signatures of the different basement rocks forming Gabal Al Adraq area, the RGB band ratio image (5/7, 5/1, 4) is proved to be very effective in the discrimination of the different basement rocks and the gold bearing alteration zones. The gold mineralization is introduced into the listwaenites, alteration zones and quartz veins during the sulfidization processes and the remobilization of gold took place along the thrust zones during listwaenization. This study indicates that the alteration zones in both the metavolcanics and the listwaenites are promising and need more detailed exploration for Au and Ag mineralizations to evaluate their potentiality.

Sadek, M. F.; Ramadan, T. M.; Abu El Leil, I.; Salem, S. M.

2006-09-01

158

Characterization of the thermally metamorphosed mantle-crust transition zone of the Neoproterozoic ophiolite at Gebel Mudarjaj, south Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

A suite of mantle-crust transition zone (Moho transition zone = MTZ) rocks are exceptionally well exposed in Gebel Mudarjaj area, southeastern desert of Egypt. The MTZ rocks were thermally metamorphosed by younger granitic intrusion, forming mafic-ultramafic hornfels with characteristic metamorphic mineral assemblages. The MTZ rocks are remarkably thin (30-50 m thick) and are composed mainly of dunites, troctolites, gabbroic rocks and pyroxenite masses overlying a basal serpentinized mantle harzburgite section. The Cr# of spinels of the basal serpentinized harzburgites and the MTZ dunites are on average 0.76 and 0.74, respectively, which is consistent with the range for arc peridotite spinels. The melt in equilibrium with these MTZ rocks is compositionally similar to boninitic magmas produced by high degrees of partial melting. The basal harzburgites and MTZ dunites have been produced by 19-23% mantle melting, and are compositionally similar to supra-subduction zone (SSZ) peridotites. The mantle melt in equilibrium with pyroxenites was formed after 16-17% partial melting, which subsequently reacted with the lower crustal gabbroic rocks to produce pyroxenites. The occurrence of pyroxenite masses at the crust-mantle boundary suggests a medium- to high-pressure accumulation of pyroxenes in mid- to lower crustal magma chambers. The original MTZ rocks were partially or fully hydrated, prior to the granitic intrusion, during the regional metamorphism, tectonic disruption and emplacement as various fragments of a dismembered ophiolite, to form antigorite-bearing serpentinized mafic-ultramafic rocks. Progressive metamorphic assemblages then overprinted the primary features due to the contact metamorphism of the MTZ rocks. The resultant metamorphic mineral assemblages are: (1) olivine + anthophyllite + tremolite ± chlorite ± talc (in the basal serpentinites), (2) olivine + enstatite ± chlorite (in the MTZ dunites), and (3) olivine + aluminous spinel (pleonaste) + chlorite + magnetite ± enstatite (in the troctolites). The peak of thermal metamorphism was about 650°-700 °C and < 7 kb, equivalant to the upper amphibolite facies.

Ahmed, Ahmed Hassan; Gharib, Moustafa E.; Arai, Shoji

2012-06-01

159

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

PubMed

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

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

2006-07-18

160

The first occurrence of platinum group minerals (PGM) in a chromite deposit in the Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The platinum-group mineralogy (PGM) of the chromitite from Gebel Lawi, in the southeastern desert has been investigated. The most abundant base metal sulfides (BMS) associated with the Lawi chromite are pentlandite, millerite and heazlewoodite. The major platinum-group minerals identified were as follows: laurite (IrOsRu)S2, osmian iridium (OsIr), hollingworthite (RhAsS), tellurian arsenopalladinite (PdTeSbAs), potarite (PdHg) besides cuprian palladian gold (CuPdAu), a Pd-Sb-Hg and HgTe phases. Laurite and osmian iridium occur preferentially in chromite. Os-Ir commonly forms composite PGM with laurite. Hollingworthite and tellurian arsenopalladinite are included within serpentine and, close to the base-metal sulfides, the cuprian palladian gold shares boundaries with chromite. Potarite together with the Pd-Sb-Hg and HgTe phases are embedded in serpentine. Palladium is the most abundant PGE in the Gebel Lawi chromite. A paragenetic sequence of PGM formation is described. Textural evidence indicates that Os-, Ir- and Ru-bearing PGM formed early and were followed by Rh- and Pd-bearing PGM. The concentration of all five PGE could be magmatic, but much of the PGE mineralogy except for laurite and osmian iridium in the center of chromite grains, has been modified by subsequent processes. At later stages, the environment became Te-, Sb-, As- and Hg-rich, which finally led to the formation of low-temperature alteration minerals.

Elhaddad, M. A.

1996-07-01

161

Mesozoic stratigraphy and history of the Canning Desert and Fitzroy Valley, Western Australia  

Microsoft Academic Search

Large outcrop areas in the Canning Desert and the Fitzroy Valley of northwestern Australia consist of marine Jurassic and Upper Triassic rocks, not of Permian as formerly believed. On present knowledge, outcrops of the Triassic formations are restricted to parts of the Fitzroy and Bonaparte Gulf Basins, whereas the distribution of Jurassic (Kimmeridgian to Tithonian) rocks provides evidence for a

R. O. Brunnschweiler

1953-01-01

162

Oil and gas exploration in Egypt past, present, and future  

SciTech Connect

Egypt was among the early countries in which exploration for hydrocarbons took place. Back to 1886 when the first oil discovery was achieved and since then exploration operations were carried out covering almost every prospective area in Egypt. The history of oil exploration in Egypt passed through six stages, each of which is characterized by its own activities and reflects the impact of certain developments not only in the applied exploration techniques, but also in the work style and prevailing exploration concepts, in addition to the development in the agreement terms. Six areas could add new oil and gas reserves to Egypt, namely: N. Sinai (onshore and offshore); Nile Delta (onshore and offshore); Western Desert (onshore and offshore); Nile Valley; Red Sea; and the Gulf of Aqaba. Such areas have the prerequisites for commercial oil and/or gas accumulations including potential source rocks, good reservoirs and adequate traps in addition to effective seals. It is believed that the undiscovered oil and gas reserves of Egypt could be several times that which have been discovered so far.

Halim, M.A.

1995-08-01

163

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)

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 the published geological map shows that, most of the well-developed structural lineaments have NW, NE and ENE trends. Moreover, the average radiation dose rates in the study area, which range from 0.57 to 1.3 mSv yr-1 average, are calculated from the exposure rate for each rock unit. The dose rate levels still remain in the safe side to individuals and less than the maximum permissible from the natural gamma radiation sources, except younger granites and ring complex.

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

2013-10-01

164

A genetic model for a mesothermal Au deposit: evidence from fluid inclusions and stable isotopic studies at El Sid Gold Mine, Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

The El Sid Au mineralisation in the Fawakhir area, Eastern Desert, Egypt, is comprised of hydrothermal quartz veins cutting a Neoproterozoic granitoid pluton. The mineralisation is divided into Au-bearing, transitional and late carbonate vug stages. Pyrite- arsenopyrite and streaky pyrite-sphalerite-galena assemblages characterise the early and late episodes of the Au-bearing stage, respectively. These sulphide minerals sometimes contain Au as inclusions. Fluid inclusions from the Au-bearing stage are H2OCO2 rich fluids (ca 29-62 mole% CO2 and density, ca 0.51-0.66 g cm-3) with moderate to high salinities (ca 12-19 wt% NaCl equiv.). The trapping temperature of the ore occurred between 280 and 350°C, at pressures between 120-170 MPa (˜800-1800 m depth). However, fluid inclusions from the pyrite-arsenopyrite assemblage reflect lower homogenisation temperature measurements (Th) (265-295°C) than those in the streaky pyrite-sphalerite-galena assemblage (330-365°C). The minerals of the transitional and late carbonate vug stages (quartz and calcite) were formed between 180 and 265°C.Oxygen and H isotope data of fluid inclusions hosted in the quartz and calcite from the Au-bearing stage indicate a rather wide range of calculated ?18OH20 and ?DH20 (i.e. +3.2 to + 7.8%‰ and -75 to -32‰ , respectively). The data for the streaky pyrite-sphalerite-galena assemblage exhibit higher ?180H20 values (+ 5.3 to + 6.8%‰) and lower ?DH20 (-75 to -48‰) relative to that of the pyrite-arsenopyrite assemblage. Calculated isotopic temperatures of quartz-calcite fractionation range from 282 to 353°C and are consistent with the trapping temperatures (280-350°C).The fluid inclusion and stable isotope data imply that Au at the El Sid Gold Mine has been transported as a bisulphide complex. The high salinity and inferred occurrence of CH4 in some fluid inclusions collected from the graphite-rich zone along a serpentinite-granitoid contact suggest that the mineralising solutions gained their metal contents through circulation in the fractured zones and incorporation with a geothermal convective system by wall rock interaction. Deposition of Au sulphides has taken place at shallow crustal levels (˜800-1800 m) as a result of meteoric/magmatic-metamorphic water exchange with wall rocks through H2OCO2 immiscibility during fluid pressure drop and decreasing ligand activity.

Harraz, Hassan Z.

2000-02-01

165

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

PubMed

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

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

2010-08-25

166

Determination of persistent organic pollutants in sediment and fish of the western coast of Alexandria, Egypt  

Microsoft Academic Search

Persistent organic pollutants (POPs) were recorded in sediment and fish samples collected from the western coast of Alexandria. Total hydrocarbons (aliphatic+PAHs ) in sediment ranged from 683.8 to 34670.1 ng g with an average of 9286.9 ng g . The sum of C16–C34 of aliphatic fractions was<4000?ng g;, indicating the presence of a fresh petroleum source. For all sediments, the anthracene\\/phenanthrene ratio was>0.1, suggesting the

Tarek O. Said

2007-01-01

167

Microbiotic crusts and their interrelations with environmental factors in the Gurbantonggut desert, western China  

NASA Astrophysics Data System (ADS)

Located in the Junggar Basin in Xinjiang, the Gurbantonggut Desert is the second largest desert in China. Microbiotic crusts consisting of animalcule, lichen, moss, and algae species develop extensively in the region. Their formation, species composition and distribution pattern are closely related to the environmental conditions along the different parts of sand dune. Analysis of microbiotic crust distribution and relationship to environmental factors shows that average microbiotic crust thickness is 0.05 0.1 cm at the tops dunes, 0.2 1.5 cm in the upper part, 1.5 2.5 cm in middle and lower parts of dunes, and 1.5 5.0 cm in interdune areas, while areal coverage is 30.5, 48.5, 55.5, and 75.5%, respectively. Microbiotic crust differentiation along dune slopes is a result of the development stage and converse-succession resistance of the different microbiotic crusts. The numbers of species, thickness and degree of development of microbiotic crusts increase from the upper part to the middle and lower parts of dune slopes. The development and differentiation of microbiotic crusts at various dune slope positions are a reflection of the ecological expression of the comprehensive adaptability and natural selection of different microbiotic crust species to the local environmental conditions, and are closely related to such ecological conditions as the physiochemical properties of soils and topsoil textural stability.

Chen, Y. N.; Wang, Q.; Li, W. H.; Ruan, X.

2007-04-01

168

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)

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 migration. Homogenisation temperatures of the trans-granular H2O-NaCl inclusions are much lower (130-221°C), implying different fluids late in the shear zone formation. Fluid densities calculated from aqueous-carbonic inclusions along a single trail are between 0.88 and 0.98 g/cm3, and the resulting isochores suggest trapping pressures of 2-2.6 kbar. Based on the arsenopyrite-pyrite-pyrrhotite cotectic, arsenopyrite (30.4-30.7 wt.% As) associated with gold inclusions indicates a temperature range of 325-344°C. This ore paragenesis constrains f S2 to the range of 10-10 to 10-8.5 bar. Under such conditions, gold was likely transported mainly as bisulphide complexes by low salinity aqueous-carbonic fluids and precipitated because of variations in pH and f O2 through pressure fluctuation and CO2 effervescence as the ore fluids infiltrated the shear zone, along with precipitation of carbonate and sericite. Wallrock sulphidation also likely contributed to destabilising the gold-bisulphide complexes and precipitating gold in the hydrothermal alteration zone adjacent to the mineralised quartz veins.

Zoheir, Basem A.

2008-01-01

169

Mapping Impact Modified Sediments: Subtle Remote-Sensing Signatures of the Dakhleh Oasis Catastrophic Event, Western Desert, Egypt  

NASA Astrophysics Data System (ADS)

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 particular, Ca-Al rich glass (Dakhleh Glass) points to a catastrophic event between c. 100,000 - 200,000 years ago in this well-studied African savannah and freshwater lake, Middle Stone Age environment. The known glass deposits occur at locations separated by tens of kilometers. Here we report on mapping of remote sensing data (visible, infrared and radar) that is being used to guide wider reconnaissance of the Dakhleh Glass deposits. The remote sensing is anchored on the best-studied feature, the Dakhleh Bow Wave Structure (DBWS), where structural elements of a ˜ 400 m putative crater are preserved. These structures are highly degraded, and only subtly apparent in the remote sensing data. The Dakhleh Glass (DG), while chemically unique as a natural glass, is nowhere very extensive, and is thus only a minor constituent in each remote sensing pixel; a full mapping of DG and inferences about the initiating catastrophic event will require detailed field work. The subtle remote-sensing signatures of this relatively recent impact(s) into a sedimentary target at Dakhleh, where the erosion rate is estimated at 0.1 mm/yr, underscore the difficulty in accumulating a clear characterization of the range of sedimentary target modifications associated with smaller (100 m - 1 km) terrestrial craters.

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

2005-08-01

170

Depositional cycles: an approach to the sequence stratigraphy of the Dakhla Formation, west Dakhla-Farafra stretch, Western Desert, Egypt  

Microsoft Academic Search

The latest Campanian-Middle Palæocene Dakhla Formation has been the subject of few sedimentological studies, despite its great areal distribution. This shale\\/mudstone unit exhibits marked facies variations in a northwest-southeast direction. The facies distribution patterns, stratal geometries and type, as well as frequency of the associated microfauna, allow a possible subdivision of the Dakhla Formation into ten depositional cycles. These cycles

M. H. El-Azabi; A. El-Araby

2000-01-01

171

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

SciTech Connect

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.

Calderone, G.J. (Geological Survey, Flagstaff, AZ (United States)); Butler, R.F.; Acton, G.D. (Univ. of Arizona, Tucson (United States))

1990-01-10

172

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

Microsoft Academic Search

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

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

2011-01-01

173

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

Microsoft Academic Search

.   Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams\\u000a in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable\\u000a isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek\\u000a Washes indicate that infiltration

John A. Izbicki; John Radyk; Robert L. Michel

2002-01-01

174

Increased Sedentism in the Central Oases of the Egyptian Western Desert in the Early to Mid-Holocene: Evidence from the Peripheries  

Microsoft Academic Search

Two locations adjacent to the great central oases of the Egyptian Western Desert experienced an unusual period of sedentism\\u000a in the early to mid-Holocene. Around the Southeast Basin near Dakhleh Oasis and in the Wadi el-Midauwara above Kharga, areas\\u000a sharing close cultural ties, groups of slab structure sites attest to increased sedentism spanning 2,500 years. Kharga seems\\u000a to have been settled

Mary M. A. McDonald

2009-01-01

175

Constraints on Pleistocene pluvial climates through stable-isotope analysis of fossil-spring tufas and associated gastropods, Kharga Oasis, Egypt  

Microsoft Academic Search

Stable-isotope analyses of fossil-spring carbonates (tufas) and freshwater gastropods (Melanoides tuberculata) from the currently hyperarid Western Desert of Egypt indicate that this region received enough precipitation to support a small perennial lake during the height of the oxygen-isotope stage 6\\/5e pluvial event, and a substantial volume of spring discharge during prior pluvial phases. Tufa and gastropod oxygen-isotope ratios are generally

Jennifer R Smith; Robert Giegengack; Henry P Schwarcz

2004-01-01

176

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

USGS Publications Warehouse

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)

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

1990-01-01

177

Effects of Protective Fencing on Birds, Lizards, and Black-Tailed Hares in the Western Mojave Desert  

Microsoft Academic Search

Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evalu- ated from spring 1994 through winter 1995 at the Desert Tor- toise 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

MATTHEW BROOKS

1999-01-01

178

Extension of the Najd Shear System from Saudi Arabia to the central eastern desert of Egypt based on integrated field and LANDSAT observations  

NASA Astrophysics Data System (ADS)

The Najd Shear System in Saudi Arabia extends over 1200 km in a NW-SE direction and has a width of approximately 300 km. A digital color mosaic, compiled from seven Landsat thematic mapper scenes, was used to delineate characteristic structural features of the Najd System in the Midyan region of Saudi Arabia and to search for similar features in the Egyptian Eastern Desert. The digital mosaic was generated using ratios of Landsat thematic mapper bands (bands 5/4 × 3/4, 5/1, 5/7) that are sensitive to the rock content of Fe-bearing aluminosilicates, spectrally opaque phases, and hydroxyl-bearing or carbonate minerals, respectively. The mosaic covers approximately 130,000 km² of late Proterozoic exposures of the Arabian-Nubian Shield and has the Eastern Desert and the Midyan region placed in their approximate pre-Red Sea locations. The Ajjaj Shear Zone (AJZ) marks the termination of the Najd System against the eastern margin of the Red Sea in the Midyan region. The AJZ aligns with the central Eastern Desert, based on analysis of pre-Red Sea locations. Analyses of Landsat data and field observations show that the Ajjaj Shear Zone and the central Eastern Desert exhibit the following features in common: (1) outcrops that are generally elongate in a NW-SE direction as a result of folding, with fine-scale lithologic heterogeneity at the outcrop scale related to deformation associated with faulting; (2) NW trending left-lateral faults and ductile shear zones; (3) subhorizontal, NW trending mineral lineations, and variably dipping NW trending foliations, with local changes in attitude around large competent (e.g., granitic) bodies; and (4) lithologic contacts that are generally tectonic in nature and related to faulting. These features are less common to the north and south of both the Ajjaj Shear Zone and the central Eastern Desert. Results are consistent with the Najd Shear System extending into the Eastern Desert and dominating the structural patterns within the central part of the Eastern Desert.

Sultan, Mohamed; Arvidson, Raymond E.; Duncan, Ian J.; Stern, Robert J.; El Kaliouby, Baher

1988-12-01

179

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

PubMed Central

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.

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

2011-01-01

180

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

PubMed

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

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

2013-03-01

181

Desert Ecosystems  

NSDL National Science Digital Library

The Desert Ecosystems site describes the geology and climate, plants and animals, and cultural history of the main U.S. desert regions including: the Mojave Desert, the Great Basin, and the Colorado/Sonoran desert. There are also descriptions and photos of water in the desert, coyotes, the desert tortoise, and the creosote bush.

182

Effects of Protective Fencing on Birds, Lizards, and Black-Tailed Hares in the Western Mojave Desert  

Microsoft Academic Search

Lepus californicus  ), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995\\u000a at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds\\u000a were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high\\u000a than a

MATTHEW BROOKS

1999-01-01

183

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)

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

Lotfy, H.

2009-04-01

184

Exploring Deserts  

NSDL National Science Digital Library

Exploring Deserts explains the process of desertification, provides links to information on types of deserts, and features information on the Sahara, Mojave, Arabian and Kalahari deserts. There are general facts on the fauna and flora in deserts such as the Desert Tortoise, Desert Kingsnake, and Golden Eagle, and descriptions of their problems of survival due to dangers such as sand dunes, sand and dust storms, and torrential rain and floods. Information is also provided on development of the deserts.

185

Sexual division of labor and central place foraging: a model for the Carson Desert of western Nevada  

Microsoft Academic Search

Archaeological models of hunter-gatherer subsistence often imply that the influence of men’s or women’s foraging effort on settlement patterns varied over time, but fail to consider how central place foraging may reflect conflicting subsistence interests between men and women. For example, earlier studies of Carson Desert prehistory suggest a semi-sedentary, gathering strategy replaced a mobile, hunting-oriented strategy in response to

David W Zeanah

2004-01-01

186

Late Neoproterozoic volcanics and associated granitoids at Wadi Ranga, south Eastern Desert, Egypt: A transition from subduction related to intra-arc magmatism  

NASA Astrophysics Data System (ADS)

The late Neoproterozoic of Wadi Ranga area, south Eastern Desert was characterized by extensive magmatism consisting predominantly of calc-alkaline older granitoids, Ranga volcanics and granite porphyry intrusions forming a belt of volcanic-intrusive complexes. Geological studies of the Ranga volcanics revealed two sequences of volcanic suites: the older mafic sequence composed essentially of basalt/basaltic andesite lava flows and the associated pyroclastics, while the younger felsic one represented by pitchstone porphyry. Geochemically, the older granitoids are exhibit low K-calc-alkaline characters and most likely formed in a convergent margin (arc) tectonic environment. Basalt/basaltic andesites are compositionally uniform with tholeiitic affinity. They have trace element characteristics of arc related volcanics with low Nb (0.2-0.9 ppm), Zr/Nb ratios of 40-81 with an average 54 compared to 32 in average N-MORB, signify a convergent margin setting with a depleted mantle wedge. Low Mg# (45 to 60 with an average 51), Co and Ni contents may be indicative of a non-plume-influenced mantle wedge. Compositionally, these mafic volcanics are commensurate with modern intra-arc basalts. REE modeling indicates that the magma from which these mafic volcanics were formed was generated by about 17-30% partial melting of a depleted mantle that composed mainly of spinel lherzolite in an extensional marginal basin. Geochemical characters of major, trace and REE patterns of the granite and pitchstone porphyries proved their formation from the same magma source which is originally different from the magma producing the mafic volcanics. The relative enrichment in K2O and LREE of the pitchstone porphyry along with the depletion in CaO and MgO relative to granite porphyry probably resulted from crustal contamination processes.

Gharib, Moustafa Esmail; Ahmed, Ahmed Hassan

2012-12-01

187

Applications of remote sensing, GIS, and groundwater flow modeling in evaluating groundwater resources: Two case studies; East Nile Delta, Egypt and Gold Valley, California, USA  

Microsoft Academic Search

Quaternary aquifer, East Nile Delta, Egypt. Due to the progressive increase in the development of desert land in Egypt, the demand for efficient water resources management and accurate land cover change information is increasing. In this study, we introduce a methodology to map and monitor land cover change patterns related to agricultural development and urban expansion in the desert fringes

Abdulaziz Mohamed Abdelaziz Ali Ismael

2007-01-01

188

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

PubMed

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. mitchellii, C. cerastes); and (iii) lineage diversifications that extended to Pliocene or Late Miocene (C. mitchellii, C. cerastes). Clade-diversifying and clade-constraining effects impacted the four species of rattlesnakes unequally. We found relatively high levels of molecular diversification in the two most broadly distributed species (C. mitchellii, C. cerastes), and lower levels of genetic diversification in the two species (C. tigris, C. ruber) whose ranges are relatively more restricted. Furthermore, in several cases, the distributions of subspecies were not congruent with our molecular information. We suggest regional conservation perspectives for southwestern deserts cannot rely upon subspecies as biodiversity surrogates, but must instead employ a molecular and deep historical perspective as a primary mechanism to frame biodiversity reserves within this region. PMID:16968275

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

2006-10-01

189

Current status of phytoparasitic nematodes and their host plants in Egypt  

Technology Transfer Automated Retrieval System (TEKTRAN)

In Egypt many phytoparasitic nematodes constitute a major constraint to agricultural production, especially in sandy soil and reclaimed desert lands. Nematological surveys were conducted to determine the genera and species of phytoparasitic nematodes on associated host plants in Egypt. The results i...

190

Gold of the Pharaohs – 6000 years of gold mining in Egypt and Nubia  

Microsoft Academic Search

The legendary wealth in gold of ancient Egypt seems to correspond with an unexpected high number of gold production sites in the Eastern Desert of Egypt and Nubia. This contribution introduces briefly the general geology of these vast regions and discusses the geology of the different varieties of the primary gold occurrences (always related to auriferous quartz mineralization in veins

Dietrich Klemm; Rosemarie Klemm; Andreas Murr

2001-01-01

191

The wood flora of the Cairo Petrified Forest, with five Paleogene new legume records for Egypt  

Microsoft Academic Search

Scattered palaeobotanical information pertaining to the Cairo Petrified Forest in the Eastern Desert is summarized here, for the first time since over 150years. Examined wood specimens recently collected from the Cairo Petrified Forest belonged to seven legume species of which five are new records for Egypt, bringing the total known from this Forest to twenty-one species and from Egypt to

Wagieh El-Saadawi; Marwah M. Kamal-El-Din; Yusri Attia; Marwa W. El-Faramawi

2011-01-01

192

Fission-track analysis of basement apatites at the western margin of the Gulf of Suez rift, Egypt: evidence for synchroneity of uplift and subsidence  

NASA Astrophysics Data System (ADS)

Fifty-six apatite fission-track ages and 52 horizontal confined track-length measurements are reported from Precambrian crystalline rocks along the western margin of the Gulf of Suez, Egypt. Ages fall in the range of ca. 11-385 m.y. and older ages often occur within very close geographic proximity to younger ones, indicating non-uniform uplift. The wide range in ages is accompanied by a systematic variation in the distribution of horizontal confined fission track lengths. On the basis of apatite fission track ages and their length distributions, data fall into three distinct groups. Group I: ages ranging from 43 to 385 m.y. Length distributions are all positively skewed and with decreasing age become progressively broader with shorter mean track length. Group II: ages ranging from 23 to 31 m.y. Length distributions are negatively skewed with either a distinct tail or a small peak of short tracks. Group III: ages ranging from 11 to 20.5 m.y. Length distributions are al unimodal, narrow, negatively skewed and have the longest mean lengths among samples studied. Apatite ages from groups I and II are interpreted as ``mixed ages'' as a result of cooling during uplift from different levels within the apatite partial track annealing zone. Ages from Group III are interpreted as ``cooling ages'' due to uplift from the apatite total track annealing zone with minor partial annealing. Correcting the ages of the two oldest samples in this group for track-length reduction yields ages of 21 +/- 2.2 and 23 +/- 1.5 m.y. It is proposed that the onset of rift-flank uplift in the Gulf of Suez-northern Red Sea area occurred between 21 and 23 m.y. ago. Fission-track analysis in combination with subsidence data from the Gulf of Suez basin, indicate that commencement of basement uplift postdate the start of rifting and is interpreted as evidence for passive rifting at the Gulf of Suez. Furthermore, this uplift is contemporaneous with, and is directly related to, the process of extension and subsidence at the Gulf of Suez.

Omar, Gomaa I.; Steckler, Michael S.; Buck, W. Roger; Kohn, Barry P.

1989-09-01

193

Ancient Egypt.  

ERIC Educational Resources Information Center

|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…

Evers, Virginia

194

Economic analysis of water allocation policies regarding Nile River water in Egypt  

Microsoft Academic Search

The Government of Egypt is currently implementing projects that expand irrigated area on the Sinai Peninsula and in the southern desert. Those projects will reduce the supply of Nile River water available to farmers in the Nile Delta, which is a heavily populated and highly productive agricultural region. The southern desert project will obtain water directly from Lake Nasser, while

Dennis Wichelns

2002-01-01

195

The Nubian Aquifer in Southwest Egypt  

Microsoft Academic Search

Synthetic Aperture Radar (SAR) images, and topographic and groundwater data are used to understand heterogeneities of the\\u000a Nubian Aquifer between 20–24.5°N and 25–32°E in southwest Egypt. New fluvial and structural interpretations emphasize that\\u000a the desert landscape was produced by fluvial action, including newly mapped alluvial fans. In central locations, braided channels\\u000a are spatially aligned with a NE structural trend, suggesting

C. A. Robinson; A. Werwer; F. El-Baz; M. El-Shazly; T. Fritch; T. Kusky

2007-01-01

196

Eternal Egypt  

NSDL National Science Digital Library

Available in English, French, and Arabic, Eternal Egypt is a website with a wealth of information on "the artifacts, characters, and places that together comprise the wonder that is Eternal Egypt." The website is organized so visitors can choose between a guided tour, begin with one of the cultural highlights (such as The Temple of Luxor or Part of a Wall of a Tomb), or simply explore and discover. A key feature of the website is the context provided in relation to various topics, so that a visitor can learn about the artifacts, but also how they connect to other people, places and artifacts, and where they fit in terms of an overall timeline and on a multimedia map of Egypt. Topics include: Arts and Crafts (Libraries, Architecture, Paintings and Relief, Sculpture, Humanities, Crafts), Science (Archaeology, Mathematics, Astronomy, Medicine, Social Science, Engineering), Agriculture (Irrigation, Herding, Farming, Crops), Commerce and Trade (Transportation), Government (Leaders, Seats of Power, Theocracy, Military), and Society and Culture (Family, Food and Drinks, Clothing, Sports and Entertainment, Religion and Spirituality).

197

Composition and antimicrobial activity of the essential oil of Heracleum thomsonii (Clarke) from the cold desert of the western Himalayas.  

PubMed

Volatile oil composition of hydro-distilled (HD) and supercritical carbon dioxide (SC-CO(2)) essential oil of freshly collected aerial parts of Heracleum thomsonii (Umbeliferae) from the western Himalayas was studied by GC-FID and GC-MS. Results revealed qualitative and quantitative dissimilarity in the composition of hydro-distilled and SC-CO(2) extracted oils. Nineteen constituents, which accounted for 89.32% of total constituents in HD oil, represented by limonene (4.31%), (Z)-?-ocimene (3.69%), terpinolene (22.24%), neryl acetate (36.19%), nerol (9.51%) and p-cymene-8-ol (2.61%) were identified. In SC-CO(2) extracted oil, 24 constituents representing 89.95% of total constituents were identified. Terpinolene (5.08%), germacrene D (2.17%), neryl acetate (51.62%), nerol (9.78%), geranyl acetate (2.06%), ?-bisabolol (2.48%) and 1-nonadecanol (4.96%) were the dominating constituents. In vitro antimicrobial activity of hydro-distilled oil was conducted against microrobial strains including two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and five Gram-negative (Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa) bacteria as well as seven fungi (Candida albicans, Issatchenkia orientalis, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus sydowii and Trichophyton rubrum) using broth microdilution method. The results of bioassay showed that the oil exhibited moderate to high antimicrobial activity against fungi C. albicans (MIC 625 µg?ml(-1)), A. parasiticus (MIC 312.5 µg?ml(-1)), A. sydowii (MIC 312.5 µg?ml(-1)), T. rubrum (MIC 625 µg?ml(-1)), Gram-positive bacteria B. subtilis (MIC 625?µg?ml(-1)) and Gram-negative bacteria P. aeruginosa (MIC 312.5 µg?ml(-1)). PMID:21854172

Guleria, Shailja; Saini, Rikki; Jaitak, Vikas; Kaul, V K; Lal, Brij; Rahi, Praveen; Gulati, Arvind; Singh, Bikram

2011-08-01

198

Cultural Diversity or Cultural Imperialism: Liberal Education in Egypt.  

ERIC Educational Resources Information Center

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…

Blanks, David R.

1998-01-01

199

Wind modeling of Chihuahuan Desert dust outbreaks  

Microsoft Academic Search

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

Nancy I. Rivera Rivera; Thomas E. Gill; Kristi A. Gebhart; Jennifer L. Hand; Max P. Bleiweiss; Rosa M. Fitzgerald

2009-01-01

200

Desert dust aerosol air mass mapping in the western Sahara, using particle properties derived from space-based multi-angle imaging  

Microsoft Academic Search

ABSTRACT 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

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

2009-01-01

201

Hepatitis C antibody prevalence in blood donors in different governorates in Egypt.  

PubMed

Markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were sought in serum samples from 2644 blood donors in 24 of Egypt's 26 governorates. Of the 2644 samples, 656 (24.8%) were shown to contain anti-HCV immunoglobulin G antibody by Abbott second generation enzyme immunoassays (EIA). Of 85 EIA-positive samples tested by recombinant immunoblot assay, 72 (85%) were positive. HCV seroprevalence in the governorates ranged from zero to 38%; 15 governorates (62%) had an HCV antibody prevalence greater than 20%, and 6 (25%) greater than 30%. Governorates with higher sero-prevalences were located in the central and north-eastern Nile river delta, and south of Cairo in the Nile river valley. Subjects from areas in and adjoining the Sinai peninsula, in the eastern and western desert, and in southernmost Egypt, had the lowest prevalence of HCV antibody. The large urban governorates of Cairo and Alexandria had antibody prevalences of 19% and 11%, respectively. A total of 39.4% subjects had evidence of HBV infection (and-HBV core antigen total antibody). HCV infections were detected more frequently in donors with markers for HBV infections than in uninfected subjects (36% versus 18%, P < 0.001). PMID:9231192

Arthur, R R; Hassan, N F; Abdallah, M Y; el-Sharkawy, M S; Saad, M D; Hackbart, B G; Imam, I Z

202

Using the natural 15N abundance to assess the main nitrogen inputs into the sand dune area of the north-western Negev Desert (Israel).  

PubMed

The variation of the natural 15N abundance is often used to evaluate the origin of nitrogen or the pathways of N input into ecosystems. We tried to use this approach to assess the main input pathways of nitrogen into the sand dune area of the north-western Negev Desert (Israel). The following two pathways are the main sources for nitrogen input into the system: i. Biological fixation of atmospheric nitrogen by cyanobacteria present in biological crusts and by N2-fixing vascular plants (e.g. the shrub Retama raetam); ii. Atmospheric input of nitrogen by wet deposition with rainfall, dry deposition of dust containing N compounds, and gaseous deposition. Samples were taken from selected environmental compartments such as biological crusts, sand underneath these crusts (down to a depth of 90 cm), N2-fixing and non-N2-fixing plants, atmospheric bulk deposition as well as soil from arable land north of the sandy area in three field campaigns in March 1998, 1999 and 2000. The delta15N values measured were in the following ranges: grass -2.5/1000 to +1.5/1000; R. reatam: +0.5/1000 to +4.5/1000; non-N2-fixing shrubs +1/1000 to +7/1000; sand beneath the biological crusts +4/1000 to +20/1000 (soil depth 2-90 cm); and arable land to the north up to 10/1000. Thus, the natural 15N abundance of the different N pools varies significantly. Accordingly, it should be feasible to assess different input pathways from the various 15N abundances of nitrogen. For example, the biological N fixation rates of the Fabaceae shrub R. reatam from the 15N abundances measured were calculated to be 46-86% of biomass N derived from the atmosphere. The biological crusts themselves generally show slight negative 15N values (-3/1000 to -0.5/1000), which can be explained by biological N fixation. However, areas with a high share of lichens, which are unable to fix atmospheric nitrogen, show very negative values down to -10/1000. The atmospheric N bulk deposition, which amounts to 1.9-3.8 kg N/hayr, has a 15N abundance between 4.4/1000 and 11.6/1000 and is likely to be caused by dust from the arable land to the north. Thus, it cannot be responsible for the very negative values of lichens measured either. There must be an additional N input from the atmosphere with negative delta15N values, e.g. gaseous N forms (NOx, NH3). To explain these conflicting findings, detailed information is still needed on the wet, particulate and gaseous atmospheric deposition of nitrogen. PMID:15085984

Russow, Rolf; Veste, Maik; Littmann, Thomas

2004-03-01

203

Discovering Deserts.  

ERIC Educational Resources Information Center

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)…

Braus, Judy, Ed.

1985-01-01

204

Studies on the nutritional status of children aged 0–5 years in a drought-affected desert area of western Rajasthan, India  

Microsoft Academic Search

Objective: The present study was undertaken to assess the impact of drought on the nutritional status of pre-school children aged 0-5 years from a rural population in a desert area facing drought conditions very frequently. Design: The sampling design for assessment was the three-stage sampling technique. Setting: The study was carried out in 24 villages belonging to six tehsils (sub-units

Madhu B Singh; Ranjana Fotedar; J Lakshminarayana; PK Anand

2006-01-01

205

Desert Dwellers  

NSDL National Science Digital Library

This lesson plan is part of the discoveryschool.com lesson plan library for grades 9-12. This lesson focuses on desert ecology, geography, and development, with an emphasis on desertification and what can be done to prevent it. It includes objectives, materials, procedures, discussion questions, evaluation ideas, performing extensions, suggested readings, and vocabulary. There are videos available to order which complement this lesson, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

206

Metallogeny of gold in relation to the evolution of the Nubian Shield in Egypt  

Microsoft Academic Search

Gold mineralization in the Eastern Desert of Egypt is confined, almost completely, to the basement rocks of the Nubian Shield that was cratonized during the Panafrican orogeny.Island-arc, orogenic and post-orogenic stages are indicated for the tectonic-magmatic evolution of the Nubian Shield in Late Proterozoic times. Different styles of gold mineralization recognised in the Eastern Desert are inferred to have developed

Nagy Shawky Botros

2002-01-01

207

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

NASA Astrophysics Data System (ADS)

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. Résumé. Des études précédentes indiquent qu'une faible part de la recharge est assurée par l'infiltration d'écoulement de surface dans des cours temporaires du bassin supérieur de la rivière Mojave, dans la partie occidentale du désert Mojave, près de Victorville (Californie). Des données portant sur les chlorures, le tritium et les isotopes stables, recueillies dans la zone non saturée entre 1994 et 1998 grâce à des forages réalisés dans les fonds de vallées d'Oro Grande et de Sheep Creek, montrent que l'infiltration des écoulement de surface se produit en profondeur sous la zone racinaire, et probablement jusqu'à la nappe, le long de la plus grande partie du cours de l'Oro Grande et au pied des montagnes le long de celui de Sheep Creek. Des différences dans l'infiltration aux sites le long de chacun des fonds de vallée sont la conséquence de variables hydrologiques comme la proximité du pied des montagnes, la quantité d'écoulement de surface et la texture des dépôts. Des différences dans l'infiltration entre les fonds de vallée résultent de processus géomorphologiques à grande échelle. Par exemple, le vallon de l'Oro Grande entaille le cône de déjection de Victorville et l'infiltration s'est toujours produite à peu près au même endroit lors des époques géologiques récentes. Au contraire, le fonds de la vallée de Sheep Creek passe sur un cône alluvial actif et le lit du cours d'eau peut divaguer à la surface du cône au cours du temps. L'infiltration ne se produit pas en profondeur sous la zone racinaire dans les sites hors des fonds de vallée. Resumen. Estudios previos indican que hay una pequeña contribución a la recarga por infiltración de aguas superficiales en cauces intermitentes de la cuenca del Río Mojave, en el sector occidental del Desierto de Mojave, cerca de Victorville (California, Estados Unidos de América). Los datos de cloruros, tritio e isótopos estables en la zona no saturada, registrados en sondeos perforados en los torrentes Oro Grande y Sheep Creek entre 1994 y 1998, indican que dicha infiltración tiene lugar hasta profundidades superiores a la zona radicular y, presumiblemente, hasta el nivel freático. Esto acontece en gran parte del Oro Grande Wash y cerca del frente montañoso, a lo largo del Sheep Creek Wash. Las diferencias en la infiltración en puntos de cada torrente resultan de variables hidrológicas tales como la proximidad al frente montañoso, el caudal en los cauces y la textura de los depósitos subsuperficiales. Las diferencias en la infiltración entre ambos torrentes son causadas por procesos geomórficos de gran escala. Por ejemplo, el Oro Grande Wash está encajado en el abanico de Victorville, de modo que la infiltración se ha estado produciendo en aproximadamente el mismo punto durante las époc

Izbicki, John; Radyk, John; Michel, Robert

2002-04-01

208

Education in Egypt, 1978.  

ERIC Educational Resources Information Center

This publication of the National Center for Educational Research of Egypt describes the status of education in Egypt in 1978, with respect to administration, structure, the educational ladder including university education, as well as the quantitative side of education. It also briefly presents the historical background of Egyptian education, its…

Youssef, Youssef Khalil, Ed.; Ibrahim, Fawzia El-Sayed, Ed.

209

Education in Egypt, 1979.  

ERIC Educational Resources Information Center

This publication of the National Center for Educational Research of Egypt describes the status of education in Egypt in 1979, with respect to administration, structure, the educational ladder including university education, as well as the quantitative side of education. It also briefly presents the historical background of Egyptian education, its…

Youssef, Youssef Khalil, Ed.

210

Napoleon in Egypt.  

ERIC Educational Resources Information Center

|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…

Fagan, Brian

1989-01-01

211

Springs in Egypt  

Microsoft Academic Search

Examples of springs in Egypt deal only with examples of natural springs producing potable water. None of the natural springs producing highly mineralized thermal water for therapeutical are considered. No water from natural springs in Egypt is bottled. Egyptian standards state that the total dissolved solids in potable water should not exceed 1000 ppm, except in Siwa, where the only

H. Idris

1996-01-01

212

Springs in Egypt  

Microsoft Academic Search

Examples of springs in Egypt deal only with examples of natural springs producing potable water. None of the natural springs producing highly mineralized thermal water for therapeutical purposes are considered. No water from natural springs in Egypt is bottled. Egyptian standards state that the total dissolved solids in potable water should not exceed 1000 ppm, except in Siwa, where the

H. Idris

1996-01-01

213

Geochemical and hydrological processes controlling groundwater quality in Assiut Governorate, Egypt  

NASA Astrophysics Data System (ADS)

Groundwater in Assiut area, Egypt, is an important source of fresh water for human consumption, agriculture, and domestic and industrial purposes. Due to a growing population and expansion of agricultural reclamation projects in the desert fringes of the Nile Valley, there is an increasing water demand in this arid region. This study has investigated the geochemical and hydrological processes that control groundwater quality within the Pleistocene, Plio-Pleistocene, and Eocene aquifers in Assiut, in addition to the hydraulic relationships between surface and groundwater systems and the relations among the defined groundwater aquifers. A total of 28 surface and 160 groundwater samples were collected for geochemical analysis (major and minor element chemistry, and stable isotope analyses). Total dissolved solids = 182 to 5657 mg/L, water-delta 18O = -7.5 to +6.5%, and water-delta D = -55 to +32%. Geochemical and stable isotope data indicate that the principal source of recharge to the Pleistocene and Plio-Pleistocene aquifers is the surface water system (irrigation canals), while the prevalence of Na-Cl type waters in the Eocene aquifer indicates recharge by upward leakage from the underlying Nubian sandstone aquifer which contains the same Na-Cl water type. Evaporation prior to infiltration, mixing, and mineral equilibria (dissolution and precipitation) are the main factors that affect water quality. Ion exchange plays a secondary role in controlling the water chemistry of the Pleistocene aquifer, but is more effective in controlling water quality within the Plio-Pleistocene and Eocene aquifers due to the prevalence of clay minerals within the matrices. The fresh water exploited from the Eocene aquifer may be of great importance for land reclamation projects not only at the western desert fringes, but also at the eastern desert fringes of Assiut and similar settings around the River Nile south of Assiut Governorate. Results of this study will be helpful for sustainable development, and raising the standard of living of people in the Assiut area, which is one of the poorest regions of Egypt.

Mohammad, R. G.; Tempel, R.; Gomaa, M.; Korany, E.

2011-12-01

214

A golden calf in sacred space?: The future of St Katherine's monastery, Mount Sinai (Egypt)  

Microsoft Academic Search

The spectacular fortified monastery of St Katherine, continuously inhabited since the 4th century and with a library second only in historical significance to that of the Vatican, forms the epicentre of a sacred landscape surrounding Mount Sinai, in the southern Sinai desert (Egypt). This site, with religious significance for Jews, Muslims and Christians alike, is currently threatened by very rapid

Myra Shackley

1998-01-01

215

Desert test site uniformity analysis  

NASA Astrophysics Data System (ADS)

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.

Kerola, Dana X.; Bruegge, Carol J.

2009-08-01

216

Desert USA: Desert Animals And Wildlife  

NSDL National Science Digital Library

It is a miracle that life can survive in the extreme conditions of the desert. Users can learn about mammals (including wolves), insects and spiders, fish and birds(including hawks), and reptiles and amphibians (including rattlesnakes) that have adapted and, in fact, thrive in the harsh desert ecosystems. Links to related topics such as animal survival in the desert and animal rescues are included.

2000-01-01

217

Astronomy in ancient Egypt  

NASA Astrophysics Data System (ADS)

Focus: the ancients. Many of the artefacts constructed between three and six or more millennia ago in Egypt appear to be aligned in directions that have some astronomical or geographical significance.

Kitchin, Chris

2003-03-01

218

Mineral magnetic study of the Taklimakan desert sands and its relevance to the Chinese loess  

Microsoft Academic Search

SUMMARY We conducted a mineral magnetic study on sand samples from the Taklimakan desert, Tarim Basin in western China. Modern sands were collected at 19 sites in the central and western parts of the Taklimakan desert. We carried out low-field susceptibility measurements, ARM and IRM acquisitions, high- and low-temperature measurements and hysteresis measurements on these samples. Nearly stoichiometric magnetite is

M. Torii; T.-Q. Lee; K. Fukuma; T. Mishima; T. Yamazaki; H. Oda; N. Ishikawa

2001-01-01

219

MEDIA MESSAGES AND WOMEN'S BODY PERCEPTIONS IN EGYPT  

Microsoft Academic Search

This study explores the association between media exposure and women's body perceptions in Egypt. The thin ideal perpetuated through the media, eating disorders and body dissatisfaction and drive for thinness were thought to be a culturally linked phenomena confined to Western societies. This study has contributed to the debate on cultural determinism of eating disorders and body dissatisfaction in women

SHAIMA RAGAB

220

The Politics of Educational Transfer and Policymaking in Egypt  

ERIC Educational Resources Information Center

|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…

Ibrahim, Ali S.

2010-01-01

221

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

PubMed

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

Aufderheide, Arthur C

2009-12-01

222

The city of el?Amarna as a source for the study of urban society in ancient Egypt  

Microsoft Academic Search

King Akhenaten's short?lived capital of el?Amarna still seems to offer the least fragmentary example of a city layout from New Kingdom Egypt. Although often regarded as of unusual spaciousness, taking advantage of the ready availability of building land on a desert site, there are strong grounds for arguing that, at the least, its range of housing reflects a mature, developed

Barry J. Kemp

1977-01-01

223

Remote sensing of the aerosol in Cairo (Egypt): compositional variability and impact on the atmospheric transfer of solar radiation  

Microsoft Academic Search

Cairo, the capital city of Egypt, is located at the southernmost tip of the Nile Delta and is surrounded on the other three sides by deserts. As is the case in several other megacities of the World, its fast increasing population already suffers from a general worsening of their environmental conditions, and in particular of the air quality. In order

Stephane Alfaro; Mossad El-Metwally; Olivier Favez; Bernadette Chatenet; Magdy Abdel Wahab

2010-01-01

224

Egypt Daily.com  

NSDL National Science Digital Library

Part of the World News network, Egypt Daily.com provides a wealth of links to frequently updated news stories dealing primarily with Egypt. From the homepage, users can click on any number of recent items gathered from a variety of different sources, including the BBC, ABC News, Arabic News, and CNN. The archive of news items stretches back several weeks, and news items are also arranged thematically into sections dealing with the economy, tourism, and technology on the site's main page. The site also features a number of helpful links, such as those leading to English-language news resources for the Arabic-speaking world and to online newspapers in Arabic. The site is rounded out by a list of online travel guides for those seeking to plan a trip to Egypt or other parts of North Africa.

225

Dwarfs in ancient Egypt.  

PubMed

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

Kozma, Chahira

2006-02-15

226

Characteristics and functions of semi-desert soils in the Negev (Israel) depending on precipitation, relief and vegetation  

NASA Astrophysics Data System (ADS)

The Negev desert in south western Israel has been the subject of several investigations concerning soil forming processes and matter fluxes in desert soils. In order to investigate the influence of the ‘global change' on semi-desert ecosystems, study sites along a steep rainfall gradient are of great advantage. The study site "Nizzana 69", which is in the focus of this study, lies about 25 km south of the Mediterranean Sea near the border between Israel and Egypt. The area has an annual rainfall of approximately 170 mm * a-1. A catena consisting of six profiles, three under the legume Retama raetam and three in the bare interspace between shrubs was investigated in order to show the impact of this perennial plant and the relief on soil properties. The results show a strong influence of the shrub due to accumulation of nutrients, carbonates and soluble salts, which were precipitated with dust and rainfall, or which derive from mineralisation of plant litter. The interspace between the plants is covered by a biological soil crust, which also strongly influences the matter fluxes by creating runoff, nitrogen-fixation and stabilizing the soil surface and protecting it against deflation. The distribution of salts and carbonates in the profiles indicate leaching processes. All soils of the study site "Nizzana 69" are weekly developed Arenosols without horizons of carbonate or salt enrichment to a depth of 1 m. The comparison with other areas along the rainfall gradient shows higher inputs of soluble salts with increasing precipitation due to wet deposition, while carbonate contents increase with decreasing precipitation due to deposition of dust, which was generated in the lime stone Negev. On the other hand leaching of soluble soil constituents decreases and accumulation in the upper soil horizon increases with decreasing annual precipitation. Furthermore the importance of local relief aspects for plant growth decreases with increasing rainfall.

Felde, V.; Drahorad, S.; Felix-Henningsen, P.

2009-04-01

227

What's It Like Where You Live? Desert  

NSDL National Science Digital Library

This site provides excellent background information on deserts. Large print and superb pictures make this site very appealing to younger students. Topics include: What is a Desert Like?, Types of Deserts, What causes Deserts?, Deserts of the World, Desert Plants, Desert Animals, and links to other desert sites.

2002-01-01

228

Area Handbook for Egypt.  

National Technical Information Service (NTIS)

The Area Handbook for Egypt is an attempt to provide a comprehensive study of the dominant social, political, and economic aspects of the Egyptian society and to identify the patterns of behavior characteristic of its members. The study results from the c...

R. F. Nyrop B. L. Benderly W. W. Cover D. R. Eglin R. A. Kirchner

1976-01-01

229

Environmental health in Egypt  

Microsoft Academic Search

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

Wagida A. Anwar

2003-01-01

230

Scientific Exploration in Egypt  

Microsoft Academic Search

Now that we have embarked in a war in Egypt, it is to be hoped that steps will be taken to have a proper staff of scientific explorers attached to the army with facilities for conducting their investigations. There are periods of rest in a campaign during which soldiers and others may be usefully employed in conducting excavations at comparatively

A. Pitt-Rivers

1882-01-01

231

Atacama Desert Soil Microbiology  

Microsoft Academic Search

The Atacama Desert is an ancient temperate desert (mean annual temperature of 14–16°C) that extends across 1,000 km from 30°S\\u000a to 20°S along the Pacific coast of South America (McKay et al. 2003; Fig. 6.1). As discussed by Rundel et al. (1991) and Miller\\u000a (1976) the desert owes its extreme aridity to the climatic regime dominated by a constant temperature

Benito Gómez-Silva; Fred A. Rainey; Kimberley A. Warren-Rhodes; Christopher P. McKay; Rafael Navarro-González

232

Why Are Deserts Dry?  

NSDL National Science Digital Library

The deserts of the world today are not the deserts of the planet's past. Fossilized hippopotamus and elephant bones tell us that the Sahara, for instance, was a much moister and more hospitable environment 8,000 years ago than it is now. Each of the Earth's modern deserts are a consequence of one of the following mechanisms: air mass subsidence, rain shadows, distant moisture sources, or cold offshore temperatures at the sea's surface. This site uses text and scientific illustrations to describe how each of these mechanisms results in the occurrence of deserts.

233

Desert Water Keepers  

NSDL National Science Digital Library

In this outdoor, sunny day activity, learners experiment with paper leaf models to discover how some desert plants conserve water. Learners explore adaptations of various desert plants such as waxy coatings, thick stems, and spines and fine hairs to see which characteristics best help a plant hold water. Learners compare their model leaves to real desert leaves if they are available. Even in a nondesert region, the activity can be done at a local botanical garden that may include a desert plant collection or in any hot, dry area.

Science, Lawrence H.

1980-01-01

234

Reclaiming freshwater sustainability in the Cadillac Desert.  

PubMed

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

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

2010-12-13

235

Polar desert sandar, Antarctica  

Microsoft Academic Search

Because the climatic severity of Antarctic polar desert environments strongly inhibits glaciofluvial processes, outwash sediments are not as conspicuous as in parts of Iceland and Arctic Canada. However, in the Antarctic “dry valleys” numerous, small sandar, both active and relict, attest to the longterm effectiveness of low-magnitude, meltwater discharges in ancient polar desert landscapes. Many parts of these valley systems

R. B. Rains; M. J. Selby; C. J. R. Smith

1980-01-01

236

Desert Storm environmental effects  

Microsoft Academic Search

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

E. W. Kimball

1992-01-01

237

Desert Storm environmental effects  

NASA Astrophysics Data System (ADS)

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.

Kimball, E. W.

238

Negev: Land, Water, and Life in a Desert Environment  

NASA Astrophysics Data System (ADS)

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.

Back, William

239

The effect of drought on four plant communities in the northern Mojave Desert  

SciTech Connect

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.

Schultz, B.W. [Desert Research Inst., Reno, NV (United States); Ostler, W.K. [EG and G Energy Measurements, Inc., Las Vegas, NV (United States)

1993-12-31

240

The Geology of the Ka'u Desert, Hawaii as a Mars Analog  

Microsoft Academic Search

The Ka'u Desert is located on the western flank of Kilauea volcano on the Big Island of Hawaii. It is a desert because it receives little annual rainfall (about 150 mm\\/yr) but also because it is subjected to constant outgassing from Kilauea, which creates a harsh, acidic environment. Near the summit of Kilauea the Ka'u Desert is characterized by the

R. A. Craddock; R. P. Irwin; R. Williams; D. Swanson; A. D. Howard; C. Quantin; R. Kuzmin; J. R. Zimbelman

2005-01-01

241

Modern Egypt: A Development Perspective.  

ERIC Educational Resources Information Center

|Egypt is a culture which combines the traditional with the modern. This text aims to foster an appreciation of Egypt as a changing culture facing the challenges of development. Topics included are: (1) Village Life; (2) Urban Life; (3) Nile; (4) Government; (5) Agriculture; (6) Economy; (7) Health/Games; (8) Education; (9) Religion; (10)…

Scott, Rosalind; And Others

242

La Peinture en Egypte Moderne  

Microsoft Academic Search

Ancient Egyptian art carved for itself a permanent place in the annals of great artistic periods of history. The legacy of ancient Egypt has been passed on and actively absorbed by the modern generation of Egyptian painters and sculptors. The past fifty years in Egypt have been a period of true renaissance for the artist. The ancient forms have been

Gabriel Boctor

1969-01-01

243

Using Multispectral Remote Sensing Data to Extract and Analyze the Vegetation Information in Desert Areas  

Microsoft Academic Search

The coverage and spatial distribution of vegetation in desert areas are fundamental indexes to estimate the desertification severity, and acquiring vegetation information is very beneficial to carry out desertification monitoring and evaluation. Based on Landsat TM image of 2007, vegetation information of the western Gurbantunggut Desert was extracted with vegetation indexes and spectral mixture analysis. The results show that: the

Huai-bao Zhao; Tong Liu; Yao-ping Cui; Jia-qiang Lei

2009-01-01

244

THE ECOLOGY OF INSECTIVOROUS BATS IN THE SIMPSON DESERT, CENTRAL AUSTRALIA: HABITAT USE  

Microsoft Academic Search

Williams AJ and Dickman CR, 2004. The ecology of insectivorous bats in the Simpson Desert, central Australia: habitat use. Australian Mammalogy 26: 205-214. Seven species of insectivorous bats were positively identified within a regional study area in the Simpson Desert in south-western Queensland. This paper describes habitat use by this bat assemblage and the degree to which presence of water,

AMY J. WILLIAMS; CHRIS R. DICKMAN

245

Recovery rates of microbiotic crusts within a dune ecosystem in the Negev Desert  

Microsoft Academic Search

Despite the important role played by microbiotic crusts in desert ecosystems, data concerning their recovery rates are scarce and are mainly based on estimates that fluctuate between several years to a few hundred years. In order to study the recovery rates of microbiotic crusts inhabiting sand dunes in the western Negev Desert, Israel, annual measurements of chlorophyll, protein, carbohydrates and

Giora J. Kidron; Ahuva Vonshak; Aharon Abeliovich

2008-01-01

246

Effects of Desert Dust on Nutrient Cycling in the San Juan Mountains, Colorado  

Microsoft Academic Search

The San Juan Mountains of southwestern Colorado lie downwind from several major deserts and experience several dust-deposition events each year. These events appear related to storms that erode soils in the deserts of the western US and then deposit atmospheric dust from these soils during or after snowfall during large late winter and spring deposition events. To evaluate the biogeochemical

J. C. Neff; L. Farmer; T. H. Painter; C. Landry; R. Reynolds

2005-01-01

247

Transport of dust and anthropogenic aerosols across Alexandria, Egypt  

NASA Astrophysics Data System (ADS)

The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, and the Nile Delta in Egypt. We have carried out measurements acquired with a ground- based portable sun photometer (Microtops II) and the satellite-borne TERRA/Moderate Resolution Imaging Spectroradiometer (MODIS) sensor during the periods of October 1999-August 2001 and July 2002-September 2003. These measurements show a seasonal variability in aerosol optical depth (AOD) following these flow patterns. Maximum aerosol loadings accompanied by total precipitable water vapor (W) enhancements are observed during the spring and summer seasons. Pronounced changes have been observed in the Ångström exponent (?) derived from ground-based measurements over Alexandria (31.14° N, 29.59° E) during both dust and pollution periods. We have followed up the observations with a 3-day back-trajectories model to trace the probable sources and pathways of the air masses causing the observed aerosol loadings. We have also used other NASA model outputs to estimate the sea salt, dust, sulfates and black carbon AOD spatial distributions during different seasons. Our results reveal the probable source regions of these aerosol types, showing agreement with the trajectory and Ångström exponent analysis results. It is confirmed that Alexandria is subjected to different atmospheric conditions involving dust, pollution, mixed aerosols and clean sky.

El-Askary, H.; Farouk, R.; Ichoku, C.; Kafatos, M.

2009-07-01

248

Egypt at the crossroads.  

PubMed

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 are in need of repair. In order to meet water needs in the year 2000, irrigation water needs to be reclaimed. There is a race against time toe correct mismanagement. PMID:12344703

Hinrichsen, D

1992-01-01

249

Range and habitats of the desert tortoise  

USGS Publications Warehouse

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.

Germano, D.J.; Bury, R.B.; Esque, T.C.; Fritts, T.H.

1994-01-01

250

Sonoran Desert: Fragile Land of Extremes  

USGS Publications Warehouse

'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.

Produced and Directed by Wessells, Stephen

2003-01-01

251

[The wild boar of Egypt].  

PubMed

The wild boar, Sus scrofa, is not a typical member of the Egyptian wild fauna, although it appears to have lived in the Nile Delta and other suitable regions in the north of the country. However, historic populations were probably of mixed origin, including feral domestic pigs. It is incorrect, as is sometimes still done, to include the wild boar in the iconographic bestiary of Ancient Egypt and assume that the domestic pigs of Ancient Egypt derive from local wild boars. PMID:10488431

Manlius, N; Gautier, A

1999-07-01

252

Primates in the Thar Desert  

Microsoft Academic Search

India’s Thar Desert is a fascinating area. The name ‘Thar’ comes from the word ‘Tahl’ in local dialect, which denotes the\\u000a sandy ridges of dunes. Despite the Thar Desert’s inhospitable climatic conditions, it provides dynamic microecosystems for\\u000a various species of vertebrates. A variety of mammalian species of all sizes, ranging from desert rodents to monkeys, occur\\u000a in and around the

G. Agoramoorthy

253

Groundwater of Egypt: ``an environmental overview''  

NASA Astrophysics Data System (ADS)

Although Egypt has the great Nile River, which is the main supply of water, Egypt’s water is limited to 55.5 billion m3 per annum. Owing to the rapid growth of the population and the increasing consumption of water in agriculture, industry, domestic use, etc., it is expected that Egypt will rely to some extent on groundwater to develop the new projects such as Tushka in Upper Egypt and East Oweinat. Issues related to groundwater in Egypt are identified with the common geological features associated with formation of the aquifers and demonstrating the location of the main resources of groundwater, followed by the main objective of this paper, which is addressing the environmental issues related to groundwater in Egypt. Several studies have been reviewed and personal communication made with the authorities to introduce this work and provide an overview of the groundwater quality problems in Egypt with examples from different parts of the country.

El Tahlawi, M. R.; Farrag, A. A.; Ahmed, S. S.

2008-08-01

254

Potential wind power generation in South Egypt  

Microsoft Academic Search

Egypt is one of the developing countries. The production of electricity in Egypt is basically on petroleum, natural gas, hydro-power and wind energy. The objective of this work to prove the availability of sufficient wind potential in the wide area of deep south Egypt for the operation of wind turbines there. Nevertheless, it gives in general an approximate profile which

Ahmed Shata Ahmed

2012-01-01

255

Desert Storm communications  

Microsoft Academic Search

An overview of the communication network that supported Operation Desert Storm is presented. The system, which maintained a 98% availability rate, supported 700000 telephone calls and 152000 messages per day. More than 30000 radio frequencies were managed to provide necessary connectivity and to ensure minimum interference. The roles of communications satellites, switched networks and terrestrial systems, and packet-switched networks and

J. S. Toma

1992-01-01

256

Operation Desert Storm  

Microsoft Academic Search

This paper presents a description of the objectives, planning, observations, and reports of a Department of Veteran's Affairs Social Work Outreach Team's efforts to work with soldiers returning from Operation Desert Storm. The soldiers reported experiences with discrimination, low morale, sexual harassment, and fear.

Lola West; Susan O. Mercer; Edith Altheimer

1993-01-01

257

Desert Adaptations: Water  

NSDL National Science Digital Library

In this activity, students experiment with methods of water conservation by desert plants and animals. They will learn to observe a model situation and make inferences about real organisms, use a balance and record data, and describe and communicate observations relating to specialized organisms and interaction with a dry environment.

1998-01-01

258

Desert, Water, Sun.  

National Technical Information Service (NTIS)

The following articles are discussed: 'The Key to Life' which discusses experiments in collecting water in the desert for irrigation; 'The Sea of Hope' is the story of Nadezhda Shevchenko, a young hydrogeologist and her discovery of a source of undergroun...

V. Rybin

1974-01-01

259

Geospatial Revolution: Food Deserts  

NSDL National Science Digital Library

Food deserts refer to a lack of easy access to nutritious food. They exist all over America as an outcome of poverty. This video from Penn State Public Broadcasting’s Geospatial Revolution shows how geospatial technology can help change this reality.

Wpsu

2010-11-11

260

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)

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.

Mahmod, Wael Elham; Watanabe, Kunio; Zahr-Eldeen, Ashraf A.

2013-08-01

261

Low temperature tolerance and cold acclimation for seedlings of three Mojave Desert Yucca species exposed to elevated CO 2  

Microsoft Academic Search

Leaf tolerance to low temperatures, as determined by vital stain uptake and chlorophyll a fluorescence, was compared for seedlings of three Yucca species native to the south-western United States: Yucca brevifolia, which is distributed throughout the Mojave Desert;Yucca schidigera, which occurs in both coastal and desert California; and Yucca whipplei, which is primarily coastal but occurs in portions of the

Michael E Loik; Travis E Huxman; Erik P Hamerlynck; Stanley D Smith

2000-01-01

262

Comparison of Growth and Stress in Resident Redband Trout Held in Laboratory Simulations of Montane and Desert Summer Temperature Cycles  

Microsoft Academic Search

Within their native range in western North America, resident redband trout Oncorhynchus mykiss gairdneri occupy stream habitat from high mountains to low desert. To better understand the temperature tolerance, growth, and stress physiology of native redband trout populations and compare the resilience and responses to reciprocal environments of stocks adapted to desert or montane conditions, we conducted controlled laboratory trials.

John D. Cassinelli; Christine M. Moffitt

2010-01-01

263

Factors affecting seed germination and seedling establishment of a long-lived desert shrub ( Coleogyne ramosissima : Rosaceae)  

Microsoft Academic Search

Long-lived desert shrubs exhibit infrequent, episodic recruitment from seed. In spite of this long time scale, selection on life history attributes that affect seedling recruitment should be strong. We studied factors affecting germination phenology and seedling establishment for Coleogyne ramosissima, a dominant shrub species in the ecotone between warm and cold deserts in western North America. We also examined ecotypic

Susan E. Meyer; Burton K. Pendleton

2005-01-01

264

Effects of floristics, physiognomy and non-native vegetation on riparian bird communities in a Mojave Desert watershed  

Microsoft Academic Search

Summary 1. In the deserts of the south-western United States of America, as in many ecoregions around the world, invasion of non-native plants is modifying the structure and composition of riparian vegetation. 2. Restoration of native plant species frequently proves to be ecologically and eco- nomically difficult. In the Muddy River drainage in the Mojave Desert (Nevada, USA), eradication of

Erica Fleishman; Neil Mcdonal; Ralph Mac Nally; Dennis D. Murphy; Jack Walters; Ted Floyd

2003-01-01

265

Snow, the Great River, and the Desert  

NASA Astrophysics Data System (ADS)

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 rainfall-produced runoff occurring mostly during the sporadic summer monsoon season. Water harvesting techniques which promote heterogeneous water accumulation or production can effectively make more water available in certain areas at the expense the expense of nearby areas. The use of water ponding dikes on arid rangeland can promote increased native vegetation productivity through increases in soil moisture. Stock tanks lined with impervious material are also used to collect whatever runoff that is generated for later use. Desert dwellers living along rivers must rely on conservation measures and ingenuity in order to come up with a very limited water resource to survive. This survival is continually in doubt because population(and consequently water demand) continues to grow in these arid regions while the water supply remains relatively constant.

Rango, A.

2005-12-01

266

Health service support in Operations Desert Shield and Desert Storm.  

PubMed

Operations Desert Shield and Desert Storm have brought into focus a number of difficulties with the medical support of U.S. Army tactical forces. These difficulties include inadequate preparation of Medical Corps officers for command, inadequate medical training of field medical unit personnel, and problems utilizing available equipment to support Operation Desert Storm tactical operations. This paper will discuss these difficulties, potential solutions for these difficulties, and some unresolved issues created by or despite these potential solutions. PMID:1620376

Cardinal, P A

1992-04-01

267

Tectonic framework of northeast Egypt and its bearing on hydrocarbon exploration  

SciTech Connect

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.

Khalil, M. [Gulf of Suez Petroleum Company, Cairo (Egypt); Moustafa, A.R.

1995-08-01

268

Arizona-Sonora Desert Museum  

NSDL National Science Digital Library

The Arizona-Sonora Desert Museum is a zoo, natural history museum and botanical garden, whose mission is to inspire people to live in harmony with the natural world by fostering love, appreciation, and understanding of the Sonoran Desert. The Center for Sonoran Desert Studies conducts the educational and scientific functions of the Museum and is a hub for research, education and conservation of the Sonoran Desert Region. The Center's activities range from on-grounds and outreach education programs for school children and adults, to conducting ecological research in the Sonoran Desert region and advising museum staff, other conservation organizations, and the public on scientific and educational matters. The website has extensive information about desert ecology, environments, animals, and plants, with some content presented in Spanish. There are numerous programs and classes presented, hiking clubs, tours, and activities for Scouts.

269

Alkaline ring complexes in Egypt: Their ages and relationship in time  

NASA Astrophysics Data System (ADS)

Potassium-argon ages are presented for nine alkaline ring complexes in the Southeastern Desert of Egypt, with two or more dates for six of them. The ages range from Cambrian to Cretaceous. This contrasts with the previously held opinion that the ages of these complexes were Mesozoic-Cenozoic. A range in emplacement ages within any particular complex could not be discerned. This limits the time span of emplacement of any complex to less than a few million years. There is no obvious tectonic significance in the overall distribution of the ages. The intrusions happened periodically in time. Their ages are multiples of 52 m.y. plus 38 m.y.

Serencsits, C. Mcc.; Faul, H.; Foland, K. A.; Hussein, A. A.; Lutz, T. M.

1981-04-01

270

A Desert Park  

NSDL National Science Digital Library

This National Park Service site describes the desert and oasis ecosystems of Joshua Tree National Park as well as the cultural history of humans occupying the area. Nature sections describe the animals, plants, cryptobiotic crusts, and the geology of the park. There are sections on environmental factors such as air quality, disturbed lands, exotic species and fire ecology. There is also information on natural history and cultural history education programs provided for different grade levels.

271

Jeeps Penetrating a Hostile Desert  

ERIC Educational Resources Information Center

|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…

Bailey, Herb

2009-01-01

272

Palynology and Stratigraphy of the Nubian Sandstone in Libya and Comparison with Egypt  

NASA Astrophysics Data System (ADS)

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-level curves is used to reconstruct paleogeography. Integration of palynology with geological data and tectonic implications indicates that, despite similarity in paleogeographic processes of the Nubian Sandstone, geological and structural settings remain different. The "Nubian Sandstone" provides a typical succession that can be studied in the light of sequence stratigraphy.

Tekbali, Ali; Hlal, Osama

2013-04-01

273

Aspects of Mycorrhizae in Desert Plants  

Microsoft Academic Search

\\u000a Mycorrhizal symbioses are critical to desert plants since they face the challenges of scarce, sporadic precipitation, nutrient\\u000a deficiencies, intense solar radiation, and the high temperatures found in hot deserts. Deserts are covering increasingly more\\u000a of the Earth's surface area as desertification increases globally. Mycorrhizal desert plants have a greater chance of survival\\u000a in the harsh desert environment. Desert plants form

Martha E. Apple

274

Aspects of conservation in the excavation site of the Athribis temple in Egypt  

NASA Astrophysics Data System (ADS)

The late Ptolemaic temple of Athribis in Upper Egypt is built of regional limestone and preciously decorated with reliefs, inscriptions, plaster and polychromy. It is collapsed and only partly preserved and it disposes of some still buried rooms. The temple is situated in a desert climate and highly contaminated with soluble salts. Based on mappings of materials and preservation conditions, on investigations into the materials used and the damaging factors the development of a conservation conception for the limestone remains has been started. Conservation materials have been selected or are specially developed. A test area for some tasks has been prepared and controlled after 1 year of exposure. The paper shows the status quo of the work of the stone conservation group in an archaeological site in desert climate.

Leisen, Hans; von Plehwe-Leisen, Esther; Verbeek, Christina; Jürgens, Christine; Krause, Sabine

2008-12-01

275

U.S.-Egypt Security Cooperation after Egypt's January 2011 Revolution.  

National Technical Information Service (NTIS)

Could the leadership changes resulting from Egypt's January 2011 Revolution uproot 30 years of security cooperation between the United States and Egypt. This monograph examines how the security cooperation between the two countries, which is rooted in the...

S. S. Vogelsang

2011-01-01

276

Skeletal dysplasia in ancient Egypt.  

PubMed

The ancient Egyptian civilization lasted for over 3000 years and ended in 30 BCE. Many aspects of ancient Egyptian culture, including the existence of skeletal dysplasias, and in particular achondroplasia, are well known through the monuments and records that survived until modern times. The hot and dry climate in Egypt allowed for the preservation of bodies and skeletal anomalies. The oldest dwarf skeleton, the Badarian skeleton (4500 BCE), possibly represents an epiphyseal disorder. Among the remains of dwarfs with achondroplasia from ancient Egypt (2686-2190 BCE), exists a skeleton of a pregnant female, believed to have died during delivery with a baby's remains in situ. British museums have partial skeletons of dwarfs with achondroplasia, humeri probably affected with mucopolysaccharidoses, and a skeleton of a child with osteogenesis imperfecta. Skeletal dysplasia is also found among royal remains. The mummy of the pharaoh Siptah (1342-1197 BCE) shows a deformity of the left leg and foot. A mummified fetus, believed to be the daughter of king Tutankhamun, has scoliosis, spina bifida, and Sprengel deformity. In 2006 I reviewed the previously existing knowledge of dwarfism in ancient Egypt. The purpose of this second historical review is to add to that knowledge with an expanded contribution. The artistic documentation of people with skeletal dysplasia from ancient Egypt is plentiful including hundreds of amulets, statues, and drawing on tomb and temple walls. Examination of artistic reliefs provides a glance of the role of people with skeletal dysplasia and the societal attitudes toward them. Both artistic evidence and moral teachings in ancient Egypt reveal wide integration of individuals with disabilities into the society. PMID:19006207

Kozma, Chahira

2008-12-01

277

Lack of diet partitioning by sex in reintroduced desert bighorn sheep  

Microsoft Academic Search

Desert bighorn sheep (Ovis canadensis mexicana) became extinct in Texas, U.S.A., during the 1960s and reintroduction efforts have resulted in an extant population of about 300 free-ranging animals. We studied diet preferences of reintroduced desert bighorn sheep in three mountain ranges in western Texas, U.S.A., during 1994–1995. We predicted that botanical composition and species richness of diets of reintroduced male

Timothy E. Fulbright; W. Frank Robbins; Eric C. Hellgren; Randall W. DeYoung; Ira D. Humphreys

2001-01-01

278

Desert Storm: air assault communications  

Microsoft Academic Search

The development of the US Army's 101st Airborne Division (Air Assault) Signal Battalion's command and control communications system from base-camp communications system into a system that provided division offensive communications which spanned more than 1000 miles and supported air assault ground and air combat offense operations in Iraq during Operations Desert Shield and Desert Storm is discussed. The forward operating

D. P. Salerno

1992-01-01

279

Physiological Adaptation in Desert Birds  

NSDL National Science Digital Library

This peer-reviewed article from BioScience journal is about adaptations desert birds. We call into question the idea that birds have not evolved unique physiological adaptations to desert environments. The rate at which desert larks metabolize energy is lower than in mesic species within the same family, and this lower rate of living translates into a lower overall energy requirement in the wild. We argue that selection has reduced oxygen consumption at the tissue level under basal conditions for birds living in deserts. We document that total evaporative water loss--the sum of cutaneous water loss (CWL) and respiratory water loss--is reduced in desert birds, and present evidence that changes in CWL are responsible for this pattern. The diminution in CWL is attributable to changes in the lipid structure of the stratum corneum of the skin, the physical barrier to diffusion of water vapor. Finally, we show linkages between physiology and life-history attributes of larks along an aridity gradient; birds from deserts have not only a reduced rate of metabolism but also a small clutch size and slow nestling development. Hence, attributes of physiology are correlated with traits that directly affect reproductive success. Our hope is that we will prompt students to question the notion that birds do not possess physiological adaptations to the desert environment, and raise the specter of doubt about "preadaptation" in birds living in deserts.

JOSEPH B. WILLIAMS and B. IRENE TIELEMAN (;)

2005-05-01

280

Desert Dust Satellite Retrieval Intercomparison.  

National Technical Information Service (NTIS)

This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim...

A. Smith A. M. Sayer B. Veihelmann C. Ahn C. Hsu C. Salustro C. A. Poulsen D. Antoine D. Diner D. Tanre E. Carboni F. Ducos G. E. Thomas H. Brindley J. L. Deuze O. Torres O. V. Kalashnikova P. R. J. North R. Braak R. Kahn R. Siddans R. G. Grainger S. Bevan S. DeSouza-Mchado W. Grey

2012-01-01

281

Inclusiveness in higher education in Egypt  

Microsoft Academic Search

In Egypt, before 1952, education, especially higher education, was the province of a privileged few. After the 1952 Revolution,\\u000a in pursuit of social justice and economic development, Egypt’s leaders eliminated fees, instituted a universal admission examination,\\u000a promised government employment to all graduates of higher education, and expanded the number of places. Officials expected\\u000a these policies to increase inclusiveness as enrollments

Emily Cupito; Ray Langsten

2011-01-01

282

Desert Research Institute: Research  

NSDL National Science Digital Library

Operating as the nonprofit research campus of the University and Community College System of Nevada, the Desert Research Institute (DRI) conducts more than $27 million in environmental research each year with the help of its approximately 400 research faculty and support staff. The informational research page of the main Web site offers descriptions; publications; links; and other relevant facts from the various arms of the institute, which include the Division of Atmospheric Sciences, Division of Earth and Ecosystem, Division of Hydrologic Sciences, Center for Arid Lands Environmental Management, Center for Watersheds and Environmental Sustainability, and several others.

1969-12-31

283

Egypt in the framework of global tectonics  

NASA Astrophysics Data System (ADS)

An overview is presented to explicitly describe the role of global tectonics in the tectonic and geologic history of Egypt. The major global tectonic events that have directly or indirectly affected the geology of Egypt are summarized and those events are described chronologically, emphasizing the regional geological implications of each event. It is shown that the analysis of Egyptian geological history within the framework of global tectonics suggests that most of the major geological features of Egypt can be explained in terms of the interaction of global tectonics. Finally, it appears that Egypt is entering a new phase of the Wilson cycle of opening and closing of oceans.

Morgan, Paul

284

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)

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 shorelines of the Red Sea and the Gulf of Suez suggesting a regional tectonic link between them. Strain localization of these grabens (which are likely Miocene in age) might have been facilitated by inherited Precambrian and Jurassic - Early Cretaceous structures, such as the NW-trending Najd fault system, the most dominant regional structural grain in the Red Sea Hills of Egypt as well as the NW-trending grabens, such as the Kom Ombo graben located ˜25 km to the northeast of Wadi Kubbaniya.

Roden, Jeff; Abdelsalam, Mohamed G.; Atekwana, Estella; El-Qady, Gad; Tarabees, Elhamy Aly

2011-12-01

285

Longevity and growth strategies of the desert tortoise ( Gopherus agassizii) in two American deserts  

Microsoft Academic Search

The desert tortoise occurs in two strikingly different desert regimes in the southwestern United States. In the Mojave Desert, rainfall is more irregular and resources are more limited than in the Sonoran Desert. We examined the age structure of tortoise populations from these two deserts to determine whether the difference in resource availability has driven an evolutionary divergence in life

A. J. Curtin; G. R. Zug; J. R. Spotila

2009-01-01

286

DESERT VEGETATION DURING DROUGHTS: RESPONSE AND SENSITIVITY  

Microsoft Academic Search

Desert ecosystems are characterised by large spatial and temporal variability mainly due to scarcity of moisture owing to insignificant precipitation. Desert vegetation is represented mostly by natural vegetation and least by agricultural crops. Desert plants are naturally adapted to hyper-arid climate where, rainfall is sparse and day-time temperature is very high. However, desert phenology is very sensitive to climatic parameters,

C. Bhuiyan

287

A Profile of the Military Deserter  

Microsoft Academic Search

Desertion has long been a problem of the armed forces. Hardships make desertion predictable in peacetime and wartime, but desertion is rarely stimulated by political belief. The author compares deserters from the Vietnam War to earlier U.S. wars, the German Army in World War II, and the Soviet Army in Eastern Germany. In 1974 the Army Research Institute investigated the

Edward Shils

1977-01-01

288

Trace element variation in size-fractionated African desert dusts  

Microsoft Academic Search

Desert particulate samples from locations in the Sahara–Sahel dust corridor (Western Sahara, Algeria, Chad and Niger) were segregated into size fractions ranging from 20?m and analysed using inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The size-fractionated samples contain higher concentrations of Al, Na, Mg, Fe and most trace elements in the finer, phyllosilicate-rich

Sonia Castillo; Teresa Moreno; Xavier Querol; Andrés Alastuey; Emilio Cuevas; Ludger Herrmann; Mohammed Mounkaila; Wes Gibbons

2008-01-01

289

Morphological and lithological aspects in the northeastern Libyan desert by remote sensing  

NASA Astrophysics Data System (ADS)

A multi-scale/multi-sensor approach has been applied on a portion of the Libyan Desert in Egypt, providing a morphological and lithological setting. Large depressions are the main geomorphological structure, as evidenced by DTMs created by satellite and topographical data. Bare soils are well exposed over the largest part of the area: a spectral analysis, performed on multispectral MODIS and ASTER images, has allowed the recognition of the major lithological units. The classification is a starting point for further investigations, towards a better understanding of the mutual influence between landscape and human settling during historical time.

Bitelli, G.; Curzi, P. V.; Mandanici, E.

2009-09-01

290

Supersymmetry without the Desert  

SciTech Connect

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.

Nomura, Yasunori; Poland, David

2006-09-26

291

Supersymmetry without the desert  

SciTech Connect

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 vacuum expectation values 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.

Nomura, Yasunori; Poland, David [Department of Physics, University of California, Berkeley, California 94720 (United States) and Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2007-01-01

292

Impacts of the Central Arizona Project on Desert Mule Deer and Desert Bighorn Sheep.  

National Technical Information Service (NTIS)

Desert mule deer (Odocoileus hemionus crooki) and desert bighorn sheep (Ovis canadensis mexicana) were monitored from 1979-83 to determine movements and distribution along the Granite Reef Aqueduct (GRA) of the Central Arizona Project. Desert mule deer we...

P. R. Krausman

1985-01-01

293

Serosurvey for HTLV-I Among High-Risk Populations and Normal Adults in Egypt. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

The prevalence of antibodies to human T-cell lymphotropic virus type I (HTLV-I) was determined in high-risk groups and normal adults in Egypt. Among 647 individuals tested, 6 (0.9%) were confirmed positive by western blot analysis. These included 2 (0.7%)...

N. T. Constantine M. F. Sheba A. L. Corwin R. S. Danahy J. D. Callahan

1991-01-01

294

The Hellenistic Royal Court. Court Culture, Ceremonial and Ideology in Greece, Egypt and the Near East, 336-30 BCE  

Microsoft Academic Search

In the Hellenistic empires of Alexander the Great and his successors in Greece, Egypt and the Near East, new forms of court culture and political ideology developed during the last three centuries BCE. Appropriated by Parthian kings and Roman emperors alike, the culture of these Macedonian courts eventually influenced the evolution of royal ideology and court culture in both western

R. Strootman

2007-01-01

295

Ideology, politics and sport in Egypt  

Microsoft Academic Search

This paper discusses the status of sport in contemporary Egypt, providing a brief background from Ancient Egypt through its Roman period and Islamic era. The British are credited with the introduction of modern organized sport into Eygpt. With the rise of nationalism and relative affluence of middle-class Egyptians, the number of athletic clubs increased between the two world wars. Nasser's

Hilmi M. Ibrahim; Nahed F. Asker

1984-01-01

296

Environmental, developmental and health perspectives in Egypt  

Microsoft Academic Search

Discusses environment and development improvement; the prevention and eradication of prevalent diseases and disabilities, as well as drastic abatement in both severe and moderate malnutrition in Egypt. The health of women and children in Egypt is a reflection of the general health of the population. Simultaneously, the religious and environmental climate influences the socio-economic and health situation, as well as

Chrysanthus Chukwuma

1995-01-01

297

Treatment of childhood diarrhea in rural Egypt  

Microsoft Academic Search

The Egypt National Control of Diarrheal Diseases Project, implemented between 1983 and 1991, is widely regarded as one of the most successful national oral rehydration programs. Data from a longitudinal household survey conducted in 1990–1991 in rural Egypt indicate substantial increases in both knowledge and use of oral rehydration salts during the 1980s. However, the same data show that treatment

Ray Langsten; Kenneth Hill

1995-01-01

298

PETRIFIED WOOD FROM THE FARAFRA OASIS, EGYPT  

Microsoft Academic Search

SUMMARY Two fossil wood species Celastrinoxylon celastroides and Ficoxylon cretaceum are reported and described for the first time from the Farafra Oasis in Egypt. They are compared to earlier descriptions of these spe- cies from Egypt and other parts of Africa.

Marwah M. Kamal El-Din

299

Country Analysis Briefs: Egypt, July 31, 2013.  

National Technical Information Service (NTIS)

Egypt is the largest oil producer in Africa that is not a member of the Organization of the Petroleum Exporting Countries (OPEC), and the second largest natural gas producer on the continent, following Algeria. Egypt plays a vital role in international en...

2013-01-01

300

A profile of poverty in Egypt: 1997  

Microsoft Academic Search

This paper presents a profile of poverty in Egypt for 1997. It assesses the magnitude of poverty and its distribution across geographic and socioeconomic groups, provides information on the characteristics of the poor, illustrates the heterogeneity among the poor, and helps identify empirical correlates of poverty. The poverty profile is constructed using data from the recently completed Egypt Integrated Household

Gaurav Datt; Dean Jolliffe; Manohar Sharma

1998-01-01

301

Benchmarking performance: Environmental impact statements in Egypt  

Microsoft Academic Search

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

El-Sayed A. Badr; Ashraf A. Zahran; Matthew Cashmore

2011-01-01

302

"Metabolic switch" for desert survival.  

PubMed Central

Food, like water, is in short supply in the desert. We report a specialized mechanism used by a desert mouse for surviving prolonged food shortages. The key element of this adaptation is a large reduction in resting metabolism. After about 2 weeks of restricted food intake (50% of normal), the desert mouse "switched down" its resting metabolism and was able to survive and maintain its weight indefinitely on these limited rations. When food was again freely available, resting metabolism "switched up," returning to normal levels in a single day. The reduced metabolism occurred without a decrease in body temperature or in levels of activity. In marked contrast, metabolism of the laboratory white mouse increased during food restriction, and the experiments had to be terminated to avoid starvation. We think this "metabolic switch" is common among desert mammals. It may be an amplification of a general metabolic response for coping with food scarcity common to all mammals, including humans.

Merkt, J R; Taylor, C R

1994-01-01

303

Ophthalmomyiasis during Operation Desert Shield.  

PubMed

A case of fly larva infestation of the eye (ophthalmomyiasis) is reported in an American soldier serving in Operation Desert Shield. Background information, prognosis, and treatment are discussed. PMID:1956540

Torok, P G; Davis, D L; Roley, E

1991-08-01

304

Orbital and Ground-penetrating Radar Studies of Mars-analog Terrain in Egypt  

NASA Astrophysics Data System (ADS)

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-like alluvial environments requires additional study.

Maxwell, T. A.; Grant, J. A.; Campbell, B. A.

2007-05-01

305

The Kamil Crater in Egypt.  

PubMed

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

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

2010-07-22

306

Genome Sequences of SAT 2 Foot-and-Mouth Disease Viruses from Egypt and Palestinian Autonomous Territories (Gaza Strip)  

PubMed Central

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.

Valdazo-Gonzalez, Begona; Knowles, Nick J.; Hammond, Jef

2012-01-01

307

Desert and desertification in Iran  

NASA Astrophysics Data System (ADS)

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 pavement), Kalut (Yardang), Hoodoo and wind deposited features such as different kinds of sand dunes (Seif, Nebka, Rebdous, Barkhan, Ghourd, Erg) and Loess, most of which exhibit beautiful landscapes suitable for ecotourism and scientific tours. Salt deserts (Kavir or Playas), which rest in the lowest parts of internal depressions, are the most current features in Iran deserts. The most extensive and specific salt deserts are in the course of floods or at the end of them, which consist of fine grained sediments in the lowest parts of the depressions. Many factors have been participated in the formation of salt deserts in Iran, the most important of which, are morphotectonical (such as folding and faulting due to the last epirogenic and orogenic movements), climatical and hydrological (occurred in Quaternary), geological and pedological (such as the presence of Neogene evaporitic formations).

Bahrami, M.

2009-04-01

308

The Landscape Evolution of Ulan Buh Desert in North China during Late Quaternary  

NASA Astrophysics Data System (ADS)

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.

Chen, Fahu; Li, Guoqiang; Zhao, Hui; Jin, Ming; Fan, Yuxin; Madsen, David; Chun, Xi

2013-04-01

309

Structure of desert seed banks: comparisons across four North American desert sites  

Microsoft Academic Search

The similarities and differences in seed bank structure across four locations in the North American deserts (Curlew Valley, Utah in the Great Basin; Rock Valley, Nevada in the Mojave Desert; Silverbell, Arizona in the Sonoran Desert; and Jornada, New Mexico in the Chihuahuan Desert) were compared using published data. Species composition at Curlew Valley was most distinctive among the four

Qinfeng Guo; Philip W Rundel; David W Goodall

1999-01-01

310

Diversity and adaptations in the Mojave desert  

NSDL National Science Digital Library

Deserts are characterized by low humidity, little rainfall, extreme temperatures, and a small amount of vegetation. However, deserts are not "dead zones" and host a variety of organisms adapted to these conditions.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

311

Pinacate beetle from the Mojave desert  

NSDL National Science Digital Library

The beetle's outer covering helps it survive in the harsh desert environment. These beetles also give off an unpleasant smell to deter predators. Beetles and other insects are eaten in the desert for their water and nutrient content.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

312

REE geochemistry of the recent playa sediments from the Thar Desert, India: An implication to playa sediment provenance  

Microsoft Academic Search

The playas (saline lakes) situated in the Thar Desert, north-west India, provide prominent examples of alkaline brine and varying assemblages of detrital and evaporite mineralogy. The eastern margin of the desert is relatively semi-arid, whereas the central to western region is arid to hyper-arid in nature. Rare earth elements (REEs) systematics in the sediments of nine different playas of the

P. D. Roy; W. Smykatzkloss

2007-01-01

313

Food Policy Analysis in Rural Egypt.  

National Technical Information Service (NTIS)

Egypt's food and agricultural policy is not well coordinated with policies to promote adequate nutrition, for under-and malnutrition are prevalent in spite of government food subsidies, rationing, and other programs, e.g., making cheap bread available to ...

C. Benito S. Lane

1983-01-01

314

Egypt: Major Constraints to Increasing Agricultural Productivity.  

National Technical Information Service (NTIS)

This report presents findings and major recommendations of the Egyptian-U.S. Agricultural Sector Assessment Team, assigned to appraise major constraints to increasing agricultural productivity in Egypt. Necessary background information is included. Major ...

M. K. Hindy W. S. Hoofnagle

1976-01-01

315

Economics of Processing Tomatoes in Egypt.  

National Technical Information Service (NTIS)

The report in Arabic has an English summary. Consumption of processed tomato products has been rising dramatically, leading to sharply increased imports. Egypt processes only about 1 percent of its tomato production; the industry currently is not economic...

A. K. M. Ashry

1983-01-01

316

Characterization of the aeolian terrain facies in Wadi Araba Desert, southwestern Jordan  

Microsoft Academic Search

The sand dunes in Wadi Araba Desert, southwestern Jordan, conform to the influence of two main wind systems: (1) the Shamal “ north wind”, the main determinant of dune patterns, and (2) the southerly winds caused by the Red Sea Trough and Khamasin winds. Wadi Araba is a narrow elongated morphotectonic depression bordered by the high eastern and western mountain

Walid Saqqa; Mohammad Atallah

2004-01-01

317

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 ...

318

Lake Thompson, Mojave Desert, California: A Desiccating Late Quaternary Lake System.  

National Technical Information Service (NTIS)

In late Pleistocene time, Lake Thompson rose to 710 meters above sea level and covered 950 square kilometers of the western Mojave Desert, California. During the Holocene time, the lake desiccated and is today represented mainly by Rogers, Rosamond, and B...

A. R. Orme R. Yuretich

2004-01-01

319

Fossil hyrax dung and evidence of Late Pleistocene and Holocene vegetation types in the Namib Desert  

Microsoft Academic Search

Pollen was derived from fossil dung of herbivorous hyraxes, deposited in a rock shelter on the highest mountain in Namibia, Dâures or Brandberg, situated on the Namib Desert margin. Radiocarbon dating ranging in age between modern times and 30 000 yr BP showed it represents the first empirical pollen evidence of continental palaeovegetation during the Late Pleistocene along the western

Louis Scott; Eugene Marais; George A. Brook

2004-01-01

320

Neighbor competition modifies demographic responses of desert dune annuals to gradients in sand stability  

Microsoft Academic Search

A field experiment was conducted to test the hypothesis that competitive interactions affect demographic responses of desert dune annuals to gradients in sand stability. The experiment was based on a three-way factorial design with two types of neighbor treatments (complete neighbor removalvs. control), two types of habitats (stablevs. unstable sands) and two species which characterize sandy areas of the western

Ronen Kadmon

1997-01-01

321

Project Desert Shield-Preschool Style.  

ERIC Educational Resources Information Center

Describes Project Desert Shield, a curriculum that preschool children and teachers at a U.S. military base in Germany developed to embrace and constructively deal with the interests and concerns of the children about Operation Desert Shield/Desert Storm through dramatic play. (Author/BB)

Suskind, Diane

1993-01-01

322

A Profile of Poverty in Egypt  

Microsoft Academic Search

Abstract: This paper presents a profile of poverty in Egypt for 1997. It assesses the magnitude,of poverty,and,its distribution across geographic and socioeconomic groups, provides information on the characteristics of the poor, illustrates the heterogeneity amongst the poor, and helps identify empirical correlates of poverty. This poverty profile is constructed using data from the Egypt Integrated Household Survey (EIHS), which is

Gaurav Datt; Dean Jolliffe; Manohar Sharma

2001-01-01

323

Root communication among desert shrubs.  

PubMed Central

Descriptive and experimental studies of desert shrub distributions have revealed important questions about the mechanisms by which plants interact. For example, do roots interact by mechanisms other than simple competition for limiting resources? We investigated this question using the desert shrubs Ambrosia dumosa and Larrea tridentata grown in chambers that allowed observation of roots during intraplant and intra- and interspecific interplant encounters. Two types of root "communication" were revealed. Ambrosia root systems appear to be capable of detecting and avoiding other Ambrosia root systems, whereas Larrea roots inhibit Larrea and Ambrosia roots in their vicinity. Images

Mahall, B E; Callaway, R M

1991-01-01

324

Phytoremediation for Oily Desert Soils  

Microsoft Academic Search

\\u000a This chapter deals with strategies for cleaning oily desert soils through rhizosphere technology. Bioremediation involves\\u000a two major approaches; seeding with suitable microorganisms and fertilization with microbial growth enhancing materials. Raising\\u000a suitable crops in oil-polluted desert soils fulfills both objectives. The rhizosphere of many legume and non-legume plants\\u000a is richer in oil-utilizing micro-organisms than non-vegetated soils. Furthermore, these rhizospheres also harbour

Samir Radwan

2009-01-01

325

Quantifying dust emissions from desert landforms, eastern Mojave Desert, USA  

NASA Astrophysics Data System (ADS)

The measurement of natural dust emissions from desert landforms is crucial in environmental hazard assessment and field checking the accuracy of global dust models. More than 500 individual dust measurements from eight common desert landforms in southern California were collected using the PI-SWERL (Portable In Situ Wind Erosion Lab). The largest emitters of dust are dry washes (13.787 to 0.007 mg m- 2 s- 1), dunes, playa margins, distal alluvial fans, and lacustrine beaches. Low emitters include salt-crusted playas (0.692 to 0.002 mg m- 2 s- 1), silt-clay-crusted playas, and desert pavements. High emissions are a function of saltating sand that bombards the surface, liberating dust-sized particles for entrainment. Low dust emissions are primarily a function of surface crusting, gravel armoring, and vegetation density. PI-SWERL measurements reveal that emission rates can vary by at least three orders of magnitude, reflecting local variability in soil texture and continuity of surface crusts. Shear-stress partitioning models can be applied to dust data measured by the PI-SWERL to account for large surface roughness features, such as vegetation. The results presented here give an approximation of the contributions to atmospheric dust loading by landforms in the Mojave Desert, and can potentially be used to improve atmospheric dust models.

Sweeney, Mark R.; McDonald, Eric V.; Etyemezian, Vicken

2011-12-01

326

The Nubian Sandstone Basin in North Africa, A Source of Irrigation Water for Desert Oases  

Microsoft Academic Search

\\u000a The Nubian sandstone basin in northern Africa is presented in this paper. This basin has total a total surface of about 1.8\\u000a million km2encompassing the north-western part of the Sudan, Egypt west of the Nile, the extreme north-east of Chad and southern and\\u000a eastern Libya. This surface is characterized by its extreme aridity. Groundwater is present in the Nubian basin

Mamdouh Shahin

327

Draft Environmental Report on Arab Republic of Egypt.  

National Technical Information Service (NTIS)

Current environmental problems facing Egypt are caused by the concentration of intensive agricultural irrigation and high population densities on 4% of the nation's land area. The report analyzes Egypt's natural resources of minerals, water, soil, flora a...

M. J. Wilkinson

1980-01-01

328

Economic Efficiency of Cotton Production and Ginning in Egypt.  

National Technical Information Service (NTIS)

Cotton is Egypt's most important crop representing one-fourth of the value of all field crops. The paper addresses major policy questions about cotton production and ginning in Egypt using comparative advantage analysis. Domestic resource cost (DRC), whic...

H. Khedr H. Kheir-El-Din E. Monke

1982-01-01

329

Profile of the Environmental Business Sector in Egypt.  

National Technical Information Service (NTIS)

This report is designed to help the Egyptian and U.S. private sectors participate in environmental business development in Egypt. It defines the environmental business sector in Egypt, describes products and services that the country will need, identifies...

1992-01-01

330

Modeling Soil Moisture in the Mojave Desert  

USGS Publications Warehouse

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.

Miller, David M.; Hughson, Debra; Schmidt, Kevin M.

2008-01-01

331

Showdown in the Desert The Leonid Storm of 1999: How Theory Met Reality at the Al Azraq Meteor Camp  

NASA Astrophysics Data System (ADS)

The geometrical conditions during the 1999 encounter of Earth with one of Tempel-Tuttle's dust trails lured many of the most dedicated observers into the Middle East, where the weather prospects were the best as well - a nice coincidence. While several observer groups went to either the Sinai peninsula of Egypt or Israel's Negev desert, the author followed an invitation from the Jordanian Astronomical Society (JAS) and was able to witness the celestial spectacle from the Hamzeh camp near Al Azraq in the Eastern Desert of Jordan - together with the two scientists whose predictions had favored this region of the world in the first place. This report was originally written in the days after the event.

Fischer, D.

2001-01-01

332

Media and Operation Desert Storm.  

National Technical Information Service (NTIS)

What kind of a job did the news media do in covering Operation Desert Storm. The Assistant secretary of Defense (Public Affairs), thinks they did just fine, citing public opinion polls that indicate the media's popularity rose after the war was over. But ...

R. B. Marvin

1992-01-01

333

Leaf Temperatures of Desert Plants  

Microsoft Academic Search

Temperatures of small leaves of many desert plants are within 3 degrees C of air temperature in contrast to the temperature of Opuntia in the same locale; this plant has a temperature 10 degrees to 16 degrees C above air temperature. Theoretical justification for the observation is given based on an energy budget analysis.

David M. Gates; Ronald Alderfer; Elwynn Taylor

1968-01-01

334

Desert, democracy, and consumer surplus  

Microsoft Academic Search

If one wishes to give individuals what they deserve, one must find some way of appraising those characteristics that render them deserving. In modern democratic societies, it seems attractive to base this appraisal on an aggregation of the valuations individuals hold of the desert bases under consideration. Some have argued that the market can provide such an appraisal. However, I

Teun J. Dekker

2010-01-01

335

On a Crowded Desert Island.  

ERIC Educational Resources Information Center

Suggests reference sources most appropriate for a desert island. In addition to "Robinson Crusoe" (Daniel Defoe) and a reference guide to the literature of travel, the list includes basic books on reference work, guides to reference sources, journals, an almanac, encyclopedias, a guide to English usage, and a book of quotations. (14 references)…

Rothstein, Samuel

1989-01-01

336

Desert and desertification in Iran  

Microsoft Academic Search

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

M. Bahrami

2009-01-01

337

Desert Babies Face Harsh Childhood  

NSDL National Science Digital Library

The phenomenon is the relationships between the animals and plants that inhabit the Sonoran Desert. The video shows a wide variety of animals raising their young, feeding, sheltering and protecting them. The video includes numerous examples of interactions between living things in this environment.

338

Incidence and socioeconomic determinants of abortion in rural Upper Egypt  

Microsoft Academic Search

Because of a growing cultural and religious sensitivity and controversy over reproductive health issues, particularly abortion, this area remains relatively unexplored in Egypt. This study was conducted using a participatory approach to determine the morbidity and determinants of abortion in rural Upper Egypt. In all, 1025 women from six villages in Upper Egypt were included in the study. Information regarding

KM Yassin

2000-01-01

339

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...

340

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)

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.

Sun, Youbin; Chen, Hongyun; Tada, Ryuji; Weiss, Dominik; Lin, Min; Toyoda, Shin; Yan, Yan; Isozaki, Yuko

2013-08-01

341

Using C-14 and C-14 - Be-10 for Terrestrial Ages of Desert Meteorites  

NASA Astrophysics Data System (ADS)

The arid regions of the world appear to be great storage locations for meteorites, where they can survive for long periods of time in such environments. Large numbers of meteorites have been recovered from diverse areas of and and semi-arid regions of North Africa, Arabia, North America and Western Australia. The cold desert of Antarctica is a further storehouse of meteorites. One of the first recognized areas for collections of meteorites was Roosevelt County, New Mexico. The Nullarbor region of Australia and the northern Sahara Desert in Africa are also prolific sources of meteorites.

Jull, A. J. T.; Bland, P. A.; Klandrud, S. E.; McHargue, L. R.; Bevan, A. W. R.; Kring, D. A.; Wlotzka, F.

2000-01-01

342

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

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

Graham, Matthew R; Jaeger, Jef R; Prendini, Lorenzo; Riddle, Brett R

2013-08-09

343

Desert Pathfinder at Work  

NASA Astrophysics Data System (ADS)

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 Galaxy (see spectrum at bottom). Credit: Wyrowski et al. (map), Bisschop et al. (spectrum). Millimetre and sub-millimetre astronomy opens exciting new possibility in the study of the first galaxies to have formed in the Universe and of the formation processes of stars and planets. In particular, APEX allows astronomers to study the chemistry and physical conditions of molecular clouds, that is, dense regions of gas and dust in which new stars are forming. Among the first studies made with APEX, astronomers took a first glimpse deep into cradles of massive stars, observing for example the molecular cloud G327 and measuring significant emission in carbon monoxide and complex organic molecules (see ESO PR Photo 30/05). The official inauguration of the APEX telescope will start in San Pedro de Atacama on September, 25th. The Ambassadors in Chile of some of ESO's member states, the Intendente of the Chilean Region II, the Mayor of San Pedro, the Executive Director of the Chilean Science Agency (CONICYT), the Presidents of the Communities of Sequitor and Toconao, as well as representatives of the Ministry of Foreign Affairs and Universities in Chile, will join ESO's Director General, Dr. Catherine Cesarsky, the Chairman of the APEX Board and MPIfR director, Prof. Karl Menten, and the Director of the Onsala Space Observatory, Prof. Roy Booth, in a celebration that will be held in San Pedro de Atacama. The next day, the delegation will visit the APEX base camp in Sequitor, near San Pedro, from where the telescope is operated, as well as the APEX site on the 5100m high Llano de Chajnantor.

2005-09-01

344

Microclimate control upon sand microbiotic crusts, western Negev Desert, Israel  

Microsoft Academic Search

Approximately 20% of the world's arid zones are covered by eolian sand. Parts of the sand are occupied by microbiotic crusts or have the potential of sustaining microbiotic crusts, which may have a great impact upon geomorphological processes and the ecology of the ecosystem. Any attempt to understand the distribution of microbiotic crusts inevitably necessitates knowledge concerning the microclimate within

G. J Kidron; E Barzilay; E Sachs

2000-01-01

345

Space science education for postgraduate students in Minoufiyia University, Egypt  

NASA Astrophysics Data System (ADS)

In 1986 the author with his colleagues in the Physics Department, Faculty of Science, Minoufiyia University, Minoufiyia, Egypt created a new branch in the physics department, to award the M.Sc. and Ph.D. degree in Atmospheric physics. Courses in solar, solar-terrestrial, and atmospheric physics were necessary for M.Sc. and Ph.D. students, because they not studded it before in the undergraduate level. Till now, seven students obtained on M.Sc. degree, and two students obtained on Ph.D. from the Physics Department of Minoufiya University in Solar, Solar-Terrestrial, and Space Physics, and there are one Ph.D and two M.Sc. under the awarding. This current extend to other six Egyptian Universities (Cairo, Ain Shams, Helwan, Alexandria, Mansoura, and Minua), where five students obtained on Ph.D degree, and thirteen students obtained on M.Sc. in Solar, Solar-terrestrial, and Space Physics from the six universities under the supervision of the author. In April 2002 the author succeeded to obtain on the agreement of the Minoufiyia University Council 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. Beside the research work in space science and technology, the center have the validity to award Diploma, M.Sc and Ph.D. in space science for postgraduate students. There are different courses in space science and technology for each level of the three degrees. According to the program of the European Mediterranean Countries (TEMPS III) for developing the higher education level, the center constructed a project for developing space science and technology education in the center in collaboration with European Universities and Space Research Centers. This paper explain in detail the experience in Space Science Education in Minoufiya University, and how expand it to the other universities in Egypt.

Mosalam Shaltout, M. A.

346

Rheum palaestinum (desert rhubarb), a self-irrigating desert plant.  

PubMed

The rare plant Rheum palaestinum (Polygonaceae) is a perennial hemicryptophyte that grows during the rainy winter in desert mountainous areas in Israel and Jordan that receive an average annual rainfall of ca. 75 mm. It produces between one and four large round leaves that are tightly attached to the ground and form large rosettes of up to 1 m(2). These leaves differ markedly from the typical small leaves of most desert plants. Moreover, they have a unique 3D morphology resembling a scaled-down mountainous area with well-developed steep drainage systems, raising the question which selective agents were involved in their evolution. We propose that the large leaves collect rainwater that then infiltrates the soil surrounding the root. We measured the seasonal course of leaf growth, examined the area of wet soil surrounding the root after actual and simulated rain, and modeled the water harvesting capacity using the plant leaf area and the weekly precipitation. We show that even in the slightest rains, water flows above the veins to the leaf's base where it irrigates the vertical root. A typical plant harvests more than 4,100 cm(3) of water per year, and enjoys a water regime of about 427 mm/year, equivalent to the water supply in a Mediterranean climate. This is the first example of self-irrigation by large leaves in a desert plant, creating a leaf-made mini oasis. PMID:19030840

Lev-Yadun, Simcha; Katzir, Gadi; Ne'eman, Gidi

2008-11-22

347

Rheum palaestinum (desert rhubarb), a self-irrigating desert plant  

NASA Astrophysics Data System (ADS)

The rare plant Rheum palaestinum (Polygonaceae) is a perennial hemicryptophyte that grows during the rainy winter in desert mountainous areas in Israel and Jordan that receive an average annual rainfall of ca. 75 mm. It produces between one and four large round leaves that are tightly attached to the ground and form large rosettes of up to 1 m2. These leaves differ markedly from the typical small leaves of most desert plants. Moreover, they have a unique 3D morphology resembling a scaled-down mountainous area with well-developed steep drainage systems, raising the question which selective agents were involved in their evolution. We propose that the large leaves collect rainwater that then infiltrates the soil surrounding the root. We measured the seasonal course of leaf growth, examined the area of wet soil surrounding the root after actual and simulated rain, and modeled the water harvesting capacity using the plant leaf area and the weekly precipitation. We show that even in the slightest rains, water flows above the veins to the leaf’s base where it irrigates the vertical root. A typical plant harvests more than 4,100 cm3 of water per year, and enjoys a water regime of about 427 mm/year, equivalent to the water supply in a Mediterranean climate. This is the first example of self-irrigation by large leaves in a desert plant, creating a leaf-made mini oasis.

Lev-Yadun, Simcha; Katzir, Gadi; Ne`Eman, Gidi

2009-03-01

348

The temperature responses of soil respiration in deserts: a seven desert synthesis  

Microsoft Academic Search

The temperature response of soil respiration in deserts is not well quantified. We evaluated the response of respiration to\\u000a temperatures spanning 67°C from seven deserts across North America and Greenland. Deserts have similar respiration rates in\\u000a dry soil at 20°C, and as expected, respiration rates are greater under wet conditions, rivaling rates observed for more mesic\\u000a systems. However, deserts differ

Jessica M. Cable; Kiona Ogle; Richard W. Lucas; Travis E. Huxman; Michael E. Loik; Stanley D. Smith; David T. Tissue; Brent E. Ewers; Elise Pendall; Jeffrey M. Welker; Therese N. Charlet; Meagan Cleary; Alden Griffith; Robert S. Nowak; Matthew Rogers; Heidi Steltzer; Patrick F. Sullivan; Natasja C. van Gestel

2011-01-01

349

Photosynthetic microbes in freezing deserts.  

PubMed

Polar deserts are not devoid of life despite the extreme low temperature and scarcity of water. Recently, patterned stone fields--caused by periglacial activity--have been surveyed in the Arctic and Antarctic. It was found that the productivity of the cyanobacteria and algae (hypoliths) that colonise the underside of the stones is strongly related to the pattern of the stones. The hypolith assemblages were in some cases as productive as lichens, bryophytes and plants that resided nearby. PMID:15737723

Thomas, David N

2005-03-01

350

Deserters, Social Norms, and Migration  

Microsoft Academic Search

Fourteen percent of Union Army soldiers were deserters. Were these men, who were known in their home communities to have failed cause and comrades, reintegrated into their communities? We construct a rich micropanel data set of U.S. Civil War soldiers from pro-war and anti-war communities to present new evidence on how community social norms shape soldiers’ postwar experiences. Relative to

Dora L. Costa; Matthew E. Kahn

2007-01-01

351

Desert Dust Kills Florida Fish  

NSDL National Science Digital Library

This news article details a red tide event that was spread across the Atlantic by a combination of storms in the Sahara Desert region and easterly trade winds that spread fertilized or nutrient overloaded soils to the Gulf of Mexico and Florida coastal regions. The article includes options to listen to the story via streaming audio and downloading capability. It also features colorful pictures and animations provided by NASA satellites. Related weblinks are included.

Barry, Patrick L.

2009-07-07

352

Arbuscular mycorrhizal associations in the Gurbantunggut Desert  

Microsoft Academic Search

The plants in the Gurbantunggut Desert located in Xinjiang, China are drought adapted species and grow in generally nutrient-poor\\u000a soils. A survey was conducted in the desert to determine the arbuscular mycorrhizal (AM) status associated with the desert\\u000a plants which belong to 23 species from 11 families of annuals and perennials. Roots from all plants were examined for the\\u000a presence

Changyan Tian; Zhaoyong Shi; Zhichao Chen; Gu Feng

2006-01-01

353

Historical synopses of desert RATS 1997-2010 and a preview of desert RATS 2011  

NASA Astrophysics Data System (ADS)

Desert RATS objectives, hardware, locations, and participants have changed over time. This paper provides historical perspective on the original motivations for the Desert RATS analog, and an overview of the changes in RATS over time. The lessons learned from each year are synopsized. Finally, a preview of Desert RATS 2011 tests is included.

Ross, Amy; Kosmo, Joseph; Janoiko, Barbara

2013-10-01

354

Amino Acid Analyses of Desert Varnish from the Sonoran and Mojave Deserts  

Microsoft Academic Search

There has long been a debate as to whether desert varnish deposits are microbially mediated or are deposited by inorganic processes. Several researchers have cultured bacteria from the surface of desert varnish suggesting that bacteria are intimately associated with varnish coatings and may play a role in their formation. To test this hypothesis, we have collected scrapings of desert varnish

Randall S. Perry; Michael H. Engel; Oliver Botta; James T. Staley

2003-01-01

355

Desert star (Monoptilon bellioides) flowers in bloom.  

NSDL National Science Digital Library

Desert star (Monoptilon bellioides) flowers in bloom. Desert star is an annual plant that grows in very arid regions of the southwestern United States. Desert star and other desert annuals may delay germination of some of their seeds in a bet-hedging strategy that maximizes their chances of reproductive success in a variable environment. By producing a subset of dormant seeds, plants increase the odds that some seeds will germinate in a year with conditions (such as higher rainfall amount) favorable for growth and reproduction. This photograph originally appeared on the cover of Ecology (88:5) in May of 2007.

Venable, D. L.

2010-02-12

356

Tin compounds in sediments of Lake Maryut, Egypt.  

PubMed

Concentrations of inorganic, methyl- and butyltin compounds were quantified by a hydride derivatization/atomic absorption technique for eleven short sediment cores sampled from Lake Maryut, Alexandria, Egypt. All samples contained inorganic Sn concentrations ranging from 1875 to 8190 ng g(-1) dw, the highest levels occurring in the eastern portion of the lake. Methyltin concentrations were also highest in the eastern lake, decreasing considerably in the western lake. Mono- and dimethyltins were found at all sites, the former species being the highest in concentration. Trimethyltin was much lower than either, and was absent from four out of 11 sites. An opposite trend was observed for the butyltin species, their concentration being highest in the west lake, decreasing eastward. Mono- and dibutyltin were almost equal in concentration. Although tributyltin was absent from one site in the lake, it was much higher in concentration than the two other species, particularly in the western lake. In general, methyl- and butyltin concentrations decreased with depth in the cores. Methyltin compounds appear to form within the lake mainly by methylation of inorganic Sn, and butyltin compounds are derived from anthropogenic sources. No significant correlations were found between organic C and concentrations of methyltin species. A significant negative correlation was found between total butyltin concentrations and organic C in surficial sediments. PMID:15092314

Aboul-Dahab, O; el-Sabrouti, M A; Halim, Y

1990-01-01

357

Breast-feeding in Egypt.  

PubMed

Planning, implementation and evaluation of programmes to promote appropriate infant feeding practices require detailed, current information about these practices in the target populations. To estimate the prevalences and identify the correlates of overall breast-feeding and of exclusive breast-feeding in different age periods during infancy, a cohort of 152 apparently healthy neonates and their mothers were followed during October 1987 through April 1989 in rural Bilbeis, Sharqiya Governorate, Egypt. Feeding data were collected through twice weekly home visits thus reducing the potential for bias in our findings due to respondent recall errors. The prevalence of overall breastfeeding in the infants declined from 100% in age period 0-11 weeks to 89% in age period 36-47 weeks. Mothers with previous living children were associated with significantly higher (odds ratio [OR]: 6.53, 95% confidence interval [CI]: 1.33-32.09) and ownership of refrigerators was associated with significantly lower (OR: 0.18, 95% CI: 0.05-0.67) overall breast-feeding prevalences in age periods 24-35 and 36-47 weeks, respectively. The prevalence of exclusive breast-feeding in breast-fed infants dropped from 20% in age period 0-11 weeks to 0% in age period 36-47 weeks. After multivariate adjustment, prelacteal feeding was significantly negatively (OR: 0.12, 95% CI: 0.04-0.37) associated with exclusive breast-feeding in age period 0-11 weeks. Nearly 90% of Bilbeis infants were breast-fed at age 47 weeks, but the initiation of supplementation at 0-11 weeks in 80% of breast-fed infants is contrary to current recommendations.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7844801

Hossain, M M; Reves, R R; Radwan, M M; Arafa, S A; Habib, M; DuPont, H L

1994-12-01

358

Magneto U Seismic Studies On The Estern, Part of Qattara Depression, Northwestern Desert, Egypt  

Microsoft Academic Search

The potential field data considered main factor in supporting the geo- physical exploration process in detection and evaluation the subsurface structures. In this respect a detailed land magnetic survey was performed to the studied area that was subjected to seismic investigation. The geomagnetic data was corrected and reduced to the North magnetic Pole. Since this work dealing with the tectonics,

T. T. Rabeh

2002-01-01

359

Mineral chemistry of albite-enriched granitoids at Um Ara, Southeastern Desert, Egypt  

SciTech Connect

Mineral chemistry and typomorphic characteristics are used to monitor the physicochemical evolution of late-magmatic to postmagmatic alteration processes that resulted in the development of a radioactive and albite-enriched microgranite shock. The mineral paragenesis indicates that postmagmatic fluids were enriched in Nb, Zn, U, Th, Zr, and Y, in addition to Rb, Li, and F. Manganocolumbite with extremely high Nb/(Nb+Ta) (0.99), Mn/(Mn+Fe) (0.82), and zircon with high Zr/(Zr+Hf) (0.97) indicate crystallization under alkaline, relatively high-temperature conditions (>425{degrees}C). The close association of manganocolumbite, Nb-Mn-Zn-rich ilmenite (with 1.2 to 14.5 wt% ZnO), spessartine garnet (with 68.2-89.4 mol% spessartine), zircon, xenotime, zinnwaldite mica (up to 5.98 wt% F), and fluorite indicates the strong affinity of the elements of Nb, Y, Zr, Mn, and Zn for stable complexing by K{sup +}, Na{sup +}, Li{sup +}, and F{sup -}-rich supercritical fluids during the course of extraction and transportation. The enrichment of the interacting fluid in U and Th is depicted by the presence of up to 1.6% UO{sub 2} in manganocolumbite and Hf-bearing zircon, and up to 10.5% ThO{sub 2} in monazite, in addition to locally abundant thorite and uranophane. It is suggested that the uranium mineralization, mainly as fracture fillings, formed during the waning stage of hydrothermal activity. 30 refs., 5 figs., 2 tabs.

Abdalla, Hamdy; Matsueda, Hiroharu; Ishihara, Shunso [Hokkaido Univ., Sapporo (Japan)] [and others

1994-11-01

360

Source parameters and ground motion of the Suez-Cairo shear zone earthquakes, Eastern Desert, Egypt  

Microsoft Academic Search

Three felt earthquakes with local magnitudes 4.0 (June 29th, 2000), 4.2 (July 07th, 2005) and 3.7 (October 30th, 2007) occurred\\u000a to the southeast of Cairo along the Suez-Cairo shear zone. Being the most well recorded events by the Egyptian National Seismic\\u000a Network (ENSN) in this area, they provide us an excellent opportunity to study the tectonics, the stress field, the

K. M. Abou Elenean; Adel M. E. Mohamed; H. M. Hussein

2010-01-01

361

Prevalence of external parasites in the south eastern desert of Egypt.  

PubMed

External parasites in the triangle region (Halaib & Shalatin) affecting the animal health were studied. Ectoparasites were collected in several sites by using bait traps and directly from animal bodies. Results indicated the presence of twelve species of insects belonging to seven genera included in three families (Calliphoridae, Muscidae and Sarcophagidae). Concerning ectoparasites on animal bodies, there were two species of biting lice infested goats and sheep (Bovicola caprae and B. ovis, respectively) and two species of sucking lice on goats (Linognathus africanus and L. stenopsis). Melophagus ovinus (family Hippoboscidae) collected from goats. Moreover, all camels suffered infestation with hard ticks four Hyalomma species. On the other hand, sheep and goats were infested with two Rhipicephalus species and one Haemaphysalis species. PMID:12557945

el-Baky, S M

2001-04-01

362

Uranium mineralization in the two mica granite of gabal Ribdab area, South Eastern Desert, Egypt.  

PubMed

Among the different rock units in the Gabal Ribdab area, the two-mica leucogranite and muscovite pegmatitic granite are the most favourable host rocks for uranium and thorium mineralization. The muscovite pegmatitic granite shows evidence of post-magmatic alteration, e.g. Na- and K-metasomatism, whereas the two-mica leucogranite could be regarded as being fresh. The spectrometric survey revealed the presence of three enriched zones with a maximum eU content of 140 ppm and the maximum eTh is 36 ppm. Uranophane, zippeite and becquerelite are the most abundant uranium minerals. The origin of these secondary minerals is mainly related to alteration of primary minerals by the action of oxidizing fluids, mobilization of uranium and then redeposition in other forms. Redistribution by circulating meteoric waters might have taken place. PMID:11761111

Ibrahim, M E; Saleh, G M; Abd El-Naby, H H

2001-12-01

363

Magnetic interpretation of north Gebel El Shallul area, central Eastern Desert, Egypt  

Microsoft Academic Search

The present work utilizes the aeromagnetic data supported by geology and remote sensing satellite data, to delineate surface and subsurface structural elements in north Gebel El Shallul area. Geologically, the area is covered by Precambrian basement rocks to the East (metasediments, metavolcanics, Hammamat sediments and younger granites) and Phanerozoic sediments to the West (Nubian Sandstones and Qouseir clastics).The Landsat image

Ahmed A. Khameis; Ahmed A. Nigm

2010-01-01

364

Geometry and texture of quartz veins in Wadi Atalla area, Central Eastern Desert, Egypt  

NASA Astrophysics Data System (ADS)

Several quartz vein sets with varying orientation, geometry and internal structure were recognized in the Atalla area. The veins were associated with the deformation phases affecting the area. En echelon and extensional veins are the main geometrical types. Syn-kinematic veins associated with the major northeast-over-southwest thrust faults were later boudinaged, folded and re-folded. En echelon veins, fibrous veins, and extensional veins are associated with the NNW SSE faults. Other veins are associated with the NW SE, N S, NE SW and E W faults. Veins are concentrated at the intersection zones between faults. The internal structure of the veins comprises syntaxial, antitaxial, and composite types and reflects a change from a compressive stress regime to an extensional one. Chocolate-tablet structures and synchronous and co-genetic vein networks indicate later multi-directional extension of the area. Interaction between cracking and sealing of fractures is a common feature in the study area indicating that it was easy for the pore pressure to open pre-existing fractures instead of creating new ones. The reopening of pre-existing fractures rather than creating new ones is also indicated by the scattering of vein data around ?3. There is an alteration and change in characteristics of the wall rock due to increase in fluid flow rate. Fault-valving probably is also a cause of the complex geometry of some veins.

Akawy, Ahmed

2007-02-01

365

Mineralogy and radioactivity of pegmatites from South Wadi Khuda area, Eastern Desert, Egypt  

Microsoft Academic Search

Radioactive minerals in pegmatites associated with granitic rocks are commonly encountered in the south of the Wadi Khuda\\u000a area and found as dyke-like and small bodies. They are observed within garnet-muscovite granites near the contact with older\\u000a granitoids. Field surveys indicated that the studied pegmatites vary in dimensions ranging from 2 to 10 m in width and from\\u000a 10 to

Mohamed F. Raslan; Mohamed A. Ali; Mohamed G. El-Feky

2010-01-01

366

BENEFICIATION OF URANIUM-RICH FLUORITE FROM EL - MISSIKAT MINERALIZED GRANITE, CENTRAL EASTERN DESERT, EGYPT  

Microsoft Academic Search

In a previous study, the occurrence and mineralogy of unique highly radioactive fluoriterich granites from ElMissikat uranium occurrence was discussed. The uranium content of the bulk composite sample collected from the studied fluoritebearin g granites equal 1950 ppm. The presence of ura? nium element in the core of fluorite is quite evident. The fluorite crystals are mainly responsible for the

Mohamed Fahmy Raslan

367

Molecular subtype analysis determines the association of advanced breast cancer in Egypt with favorable biology  

PubMed Central

Background Prognostic markers and molecular breast cancer subtypes reflect underlying biological tumor behavior and are important for patient management. Compared to Western countries, women in North Africa are less likely to be prognosticated and treated based on well-characterized markers such as the estrogen receptor (ER), progesterone receptor (PR) and Her2. We conducted this study to determine the prevalence of breast cancer molecular subtypes in the North African country of Egypt as a measure of underlying biological characteristics driving tumor manifestations. Methods To determine molecular subtypes we characterized over 200 tumor specimens obtained from Egypt by performing ER, PR, Her2, CK5/6, EGFR and Ki67 immunohistochemistry. Results Our study demonstrated that the Luminal A subtype, associated with favorable prognosis, was found in nearly 45% of cases examined. However, the basal-like subtype, associated with poor prognosis, was found in 11% of cases. These findings are in sharp contrast to other parts of Africa in which the basal-like subtype is over-represented. Conclusions Egyptians appear to have favorable underlying biology, albeit having advanced disease at diagnosis. These data suggest that Egyptians would largely profit from early detection of their disease. Intervention at the public health level, including education on the benefits of early detection is necessary and would likely have tremendous impact on breast cancer outcome in Egypt.

2011-01-01

368

CAN EGYPT ENHANCE FREIGHT LOGISTICS WITH COMESA?  

Microsoft Academic Search

Freight logistics plays an important role in supporting trade for all nations which directly impact economic growth. Transport routes have now become more congested and limited in some cases, in addition to the rising concern about the role of transport movements in accelerating climate change. Transportation is considered as one of the main challenges for Egypt to approach the Common

Islam El-Nakib; Charles Roberts; Gary Colquhoun

2009-01-01

369

Egypt, Morocco, and the United States  

Microsoft Academic Search

The political importance of the Middle East to the United States is evident from the willingness of the United States to wage a war in Iraq, the polit- ical capital some US administrations have invested in resolving the Pales- tinian-Israeli conflict, and the amount of aid extended to such countries as Egypt and Israel. It is not surprising, therefore, that

AHMED GALAL; ROBERT Z. LAWRENCE

2003-01-01

370

Creodonta and Carnivora from Wadi Moghra, Egypt  

Microsoft Academic Search

Six new occurrences of carnivorous mammals from Wadi Moghra, early Miocene, Egypt, are described, and the implications of these taxa for interpreting the biogeography of early Miocene mammals are discussed. The new taxa include two hyaenodontid creodonts (Buhakia moghraensis, gen. et sp. nov., and cf. Teratodon) and four carnivorans: an amphicyonid (Cynelos, sp. nov.), two viverrids s. l. (Herpestides aegypticus,

Michael Morlo; Ellen R. Miller; Ahmed N. El-Barkooky

2007-01-01

371

Women's "Justification" of Domestic Violence in Egypt  

ERIC Educational Resources Information Center

|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…

Yount, Kathryn M.; Li, Li

2009-01-01

372

Food: Tradition and change in Hellenistic Egypt  

Microsoft Academic Search

Given the predictable climate and annual flood of the Nile, a rich and varied diet was always available in Egypt, both from cultivated crops and the wild flora and fauna of the country. Evidence for diet in the Pharaonic period tends to an upper?class bias, being mainly funerary in nature. With the arrival of the Ptolemies and their Greek bureaucracy,

Dorothy J. Crawford

1979-01-01

373

CRETACEOUS WOODS FROM THE FARAFRA OASIS, EGYPT  

Microsoft Academic Search

SUMMARY There are fewer than 200 angiosperm wood records for the whole of the Cre- taceous; the majority are from North America, Europe, and Asia. This paper describes two petrified woods from the Late Cretaceous Hefhuf Formation, Farafra Oasis, Egypt, a locality near the Campanian equator. Affinities of these two wood types cannot be determined with certainty. One wood has

Marwah M. Kamal El-Din; E. A Wheeler; J. A. Bartlett

374

Journey to Egypt: A Board Game  

ERIC Educational Resources Information Center

|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…

Selvidge, Ellen

2006-01-01

375

Poverty in Egypt: Modeling and Policy Simulations  

Microsoft Academic Search

Poverty profiles are a useful way of summarizing information on the levels of poverty and the characteristics of the poor in a society, but they are limited by the bivariate nature of their informational content. Using the 1997 Egypt Integrated Household Survey (EIHS), this article estimates models of household consumption in the first stage and then predicts poverty rates corresponding

Gaurav Datt; Dean Jolliffe

2005-01-01

376

Ophthalmic medicolegal cases in Upper Egypt  

Microsoft Academic Search

PURPOSE: To describe the pattern of ophthalmic medicolegal cases with emphasis on cases of assault, and to acquaint ophthalmologists with rules pertaining to expert testimony and medical reports. METHODS: A retrospective study was carried out to review files of 247 medicolegal cases from Upper Egypt seen by the senior author in 8 years. These were classified categorically and were analyzed

Ismail A Wasfy; Ehab IA Wasfy; Tarek A Aly; Alaa A Abd-Elsayed

2009-01-01

377

Colorectal Cancer in Egypt - Does it Differ?  

Microsoft Academic Search

Colorectal cancer is a disease of the elderly, and affects the younger population with an incidence of 2 to 6%. An increasing number of young colorectal carcinoma patients attending at Mansoura University Hospital, Mansoura, Egypt, was noted. This report represents our data of the last 5 years, and compares these results with those of other countries and those previously reported

Wael Khafagy; Mohamed El-Ghazaly; Mohamed T. E-Shobaky; Mohamed Khafagy

2000-01-01

378

Proposed National Information Policy of Egypt.  

National Technical Information Service (NTIS)

A proposed statement of Egypt's national information policies is presented and some of the policies' implications for planning are discussed. The long-range purpose of these policies is to provide a motivation for generic courses of action conducive to th...

S. Adams M. A. K. Madkour V. Slamecka

1981-01-01

379

The Book-Publishing Industry in Egypt  

Microsoft Academic Search

THIS ARTICLE FOCUSES ON three aspects of the Egyptian publishing industry : title selection processes, pricing methods, and chan- nels of distribution. Since descriptive information on the industry is scarce, the orientation this paper is toward exploration rather than definitive analysis. Egypt provides a particularly good case study of Arab publishing, since it is the largest publishing country in the

NADIA A. RIZK

380

Video Usage in Egypt: Limits and Effects.  

ERIC Educational Resources Information Center

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…

El-Fawal, Nagwa Amin

381

Off-Road and the Fragile Desert  

ERIC Educational Resources Information Center

|Part one of a two-part article sets forth the dimensions and the political-cultural aspects of the use of off-road vehicles in desert areas. Presents arguments for and against off-road vehicle use on national-resource land as exemplified in the California Desert. (Editor/JR)|

Stebbins, Robert C.

1974-01-01

382

US Air Force communications in Desert Storm  

Microsoft Academic Search

The US Central Command Air Forces' (USCENTAF) communications network for Operations Desert Shield and Desert Storm is described. The Central Command Air Forces network utilized 27 SatCom terminals, 27 automatic switches, and 27 terrestrial links and had the responsibility of providing air traffic services across six countries at 24 locations handling 350000 flight operations. The system complexity and air traffic

D. D. McKenzie

1992-01-01

383

The role of dew as a moisture source for sand microbiotic crusts in the Negev Desert, Israel  

Microsoft Academic Search

Dew and fog were measured periodically during the years 1992–1995 at the Hallamish dune field, western Negev Desert (average annual rain precipitation ca. 95 mm). A major portion of the dunes are covered by cyanobacterial and moss-dominated microbiotic crusts. Chlorophyll- a measurements and microscopic examination were carried out in order to detect the possible changes in crust biomass and phenological

Giora J. Kidron; Ilana Herrnstadt; Eldad Barzilay

2002-01-01

384

PHYLOGEOGRAPHY OF BUFO PUNCTATUS: LONG TERM EVOLUTION WITHIN THE WARM DESERTS OF NORTH AMERICA AND LATE QUATERNARY RANGE SHIFTING  

EPA Science Inventory

Bufo punctatus, the red-spotted toad, is a widespread anuran of the warm-desert regions of western North America. This distribution makes this species ideal for evaluating biotic response to geotectonically and climatically mediated episodes of landscape transformation (e.g., ear...

385

REMOTE SENSING OF ECO-CLIMATIC CONDITIONS ASSOCIATED WITH THE 2004 DESERT LOCUST OUTBREAK IN NORTHWEST AND SAHELIAN AFRICA  

Technology Transfer Automated Retrieval System (TEKTRAN)

An outbreak of the Desert Locust in the spring and summer of 2004 was the worst in the last 10 years and resulted in economically significant losses to both subsistence and export agriculture across areas of northern and western Africa. An analysis of rainfall and remotely sensed vegetation index me...

386

Desert Dust Kills Florida Fish  

NSDL National Science Digital Library

This National Aeronautics and Space Administration (NASA) article discusses the connection between dust storms in Africa, and red tides along the Florida coast. Red tides are blooms of toxic algae that kill fish, birds, and mammals, as well as cause health problems in humans. Storm activity in the Sahara Desert region kicks up topsoil that winds transport into the Gulf of Mexico. These clouds fertilize the water with iron, which bacteria named Trichodesmium use to create nitrogen. The nitrogen makes the water a friendly environment for the toxic algae. This article discusses this process and research that is going on to help solve the problem. Audio version is available as well.

387

Function and change in aboriginal rock art, Western Australia  

Microsoft Academic Search

Differing approaches to Aboriginal art are discussed, including those of the diffusionists, the art critics and the social anthropologists. Regional variations in the art are distinguished with reference to the art of Kimberley, the Western Desert and Pilbara. It is suggested that such regional variations have long been a characteristic of Aboriginal art. Studies of rock art may serve to

I. M. Crawford

1972-01-01

388

Brief communication: Y-chromosome haplotypes in Egypt.  

PubMed

We analyzed Y-chromosome haplotypes in the Nile River Valley in Egypt in 274 unrelated males, using the p49a,f TaqI polymorphism. These individuals were born in three regions along the river: in Alexandria (the Delta and Lower Egypt), in Upper Egypt, and in Lower Nubia. Fifteen different p49a,f TaqI haplotypes are present in Egypt, the three most common being haplotype V (39.4%), haplotype XI (18.9%), and haplotype IV (13.9%). Haplotype V is a characteristic Arab haplotype, with a northern geographic distribution in Egypt in the Nile River Valley. Haplotype IV, characteristic of sub-Saharan populations, shows a southern geographic distribution in Egypt. PMID:12687584

Lucotte, G; Mercier, G

2003-05-01

389

Correlation of the major late Jurassic —early Tertiary low- and highstand cycles of south-west Egypt and north-west Sudan  

NASA Astrophysics Data System (ADS)

The mainly continental deposits of northwest Sudan and south-west Egypt have been correlated with coeval shallow marine and marine deposits in northern Egypt along a north-south running cross-section, based on surface and subsurface data. The palaeodepth curve of northern Egypt illustrates the gradual seal-level rise, reaching its maximum during the Late Cretaceous with conspicuous advances during the Aptian and late Cenomanian. A general highstand is also recorded during the Campanian-Maastrichtian in north-west Sudan. A detailed facies correlation is given for the Aptian and late Cenomanian highstand in western Egypt. The correlation of the Cenomanian Bahariya and Maghrabi formations displays short-term relative sealevel fluctuations. The interpretation illustrates the extensiveness of related erosional processes in the hinterland, partly intensified by temporarily uplift of the Uweinat-Aswan High in the south. Regional uplift and constant erosion took place in south-west Egypt during Coniacian and Santonian times. The regional stratigraphic gaps and uncertain interpretation of the Bahariya Uplift are induced by the influence of the Trans-African Lineament, especially during the Late Cretaceous. Low-stand fluvial sheet sandstones characterized by non-cyclic sequence development and high facies stability occur, especially in the Neocomian and early Turonian. During the Barremian and Albian, fluvial architecture changes to more cyclic fluvial sequences and increasing soil formation, due to increasing subsidence, more humid climatic conditions and the generally rising sea level, culminating in the extensive shallow marine Abu Ballas and Maghrabi formations.

Wycisk, Peter

1994-12-01

390

Habitat and population status of desert mule deer in Mexico  

Microsoft Academic Search

Summary Historically, desert mule deer (Odocoileus hemionus crooki) were distributed across the Chihuahuan Desert region in Mexico. Overgrazing and illegal hunting have been responsible for the dramatic reduction in the desert mule deer population. Through the introduction of hunting fees, desert mule deer could represent an important source of income for Mexican producers. In addition it could stimulate programs favoring

A. Martinez-Muñoz; D. G. Hewitt; S. Valenzuela; J. I. Uvalle; A. E. Estrada; J. J. Avendaño; R. Aranda

2003-01-01

391

Microbiotic crust control of runoff generation on sand dunes in the Negev Desert  

Microsoft Academic Search

The general belief that dune sands in arid regions are not likely to generate runoff and that runoff necessitates wet conditions is examined. Runoff generation was measured within an arid dune field in the western Negev Desert, Israel, during 1990–1994 on 16 plots (1.2–6.6 m2), constructed along a continuum of crust-covered crust. The relationships between chlorophyll a and carbohydrates of

Giora J. Kidron; Aaron Yair; Ahuva Vonshak; Aharon Abeliovich

2003-01-01

392

The Geology of the Ka'u Desert, Hawaii as a Mars Analog  

NASA Astrophysics Data System (ADS)

The Ka'u Desert is located on the western flank of Kilauea volcano on the Big Island of Hawaii. It is a desert because it receives little annual rainfall (about 150 mm/yr) but also because it is subjected to constant outgassing from Kilauea, which creates a harsh, acidic environment. Near the summit of Kilauea the Ka'u Desert is characterized by the Keanakako'i tephra deposit, which is several meters deep thinning out to a discontinuous deposit 1.5 km (1 mile) towards the center of the desert. The deposit itself has been incised by a number of gullies that are flat-floored and terminate in a series of amphitheater-shaped plunge pools. Most of the interior desert contains undulating weathered lava flows, extensive deposits of sand, and several more recent lava flows and volcanic edifices. The southern portion of the desert is bounded by the Hilina Pali fault scarp, which is 500 m (1,500 ft) above the nearby Pacific Ocean and contains a complex series of outwash plains, alluvial fans, and debris flows. We will present a summary of the geology of the Ka'u Desert. Contrary to published interpretations, we will present evidence that the Keanakako'i was not emplaced by two separate catastrophic eruption events but rather by two distinct eruption episodes that included multiple eruption events often interrupted by long hiatuses. Despite the morphology of the gullies contained on the Keanakako'i we will present evidence that the gullies were formed exclusively by surface runoff and not groundwater sapping, including quantitative estimates about the large amounts of discharge that occur during extreme storms. We will also present analyses of the sand deposits and determine the likely provenance of these materials. For the first time, we will also describe alluvial fans and mass wasting features on Hilina Pali and show evidence that they are part of poorly integrated channel system that originates in the Keanakako'i tephra. The Ka'u Desert represents a good Mars analog because (1) similar to valley networks, the development of channels and gullies in the Ka'u Desert has been interrupted by resurfacing events, (2) associated fluvial deposits have been heavily modified by eolian processes, and (3) the alluvial fans on the Hilina Pali have unusually large source areas.

Craddock, R. A.; Irwin, R. P.; Williams, R.; Swanson, D.; Howard, A. D.; Quantin, C.; Kuzmin, R.; Zimbelman, J. R.

2005-12-01

393

Hazard Impact And Genetic Development Of SandDunes West Of Nile Valley Egypt Egypt  

NASA Astrophysics Data System (ADS)

A SE. dune field extends west of Nile Vally (west Samalut). The dune movement and sand encroachment on the cultivated fields along the margins of the Nile flood plain represents a permanent threat to soil productivity and agricultural production in this region. In this study, the dunes has been investigated by producing geological and geomorphological maps by using Landsa ETM images for the area surrounding the dune field. Fifty sand samples had been collected from sand dunes and 5 samples were collected from substratum. Each field observation locality could be considered as a profile across the sand dune direction of movements. The sand samples are sieved and the separate samples weighed. Carrying out the collective diagrams using the computer program SITA. The granulometric indices were calculated, that is the mean grain diameter, standard deviation (measure of sorting) and skeweens Besides the sand grain features were analyzed, that is grain rounding with the use of a graniformameter, and by undertaking laboratory investigations on samples collected from various dunes. The laboratory investigations involve different granulometric parameters such as the grain rounding and frosting in the binocular microscope and morphoscopic studies. Morphoscopic studies using scanning electronic microscope (SEM) elucidate the surface process affected on sand grains. These dunes seem to have their source from a location found to the north, east and from the substratum of the dunes probably from the extensive sand and gravel deposits of Oligocene and Miocene and Quaternary age. While the sand are shiny and more rounded mat grains in the northern part of these dunes to fluvial processes. However it is not excluded that part of the sediments of the dunes are old intensively reworked aeolian sediments moving in the Western Desert during various arid phases of the Quaternary. SE movement of sands due to wind and become more markedly "aeolinized" in this direction by including less rounded and striated sand grains. They also include less clay material toward the south.

Asayed El Gammal, El; El Din El Sayed, Alaa

2010-05-01

394

The Role of Desalination in Meeting Water Supply Demands in Western Asia  

Microsoft Academic Search

The increasing gap between the supply and demand for water in the Economic and Social Commission of Western Asia (ESCWA) member countries: Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia, United Arab Emirates, and Yemen) can be attributed to the limited availability of surface water, mining of fossil groundwater sources, and water pollution mainly of shallow aquifers,

Mohamed J. Abdulrazzak; Mey Jurdi; Shiraz Basma

2002-01-01

395

African Historical Religions: A Conceptual and Ethnical Foundation for "Western Religions."  

ERIC Educational Resources Information Center

|This paper attempts to set the record straight with regard to the following assumptions: (1) the Africans of the antiquities of Ethiopia and Egypt were black people; and (2) the same black people developed the foundation that provides the basis for the so-called major Western religions of Judaism, Christianity, and Islam. There are two parts to…

Alexander, E. Curtis

396

Effects of added Zn, Ni and Cd on desert shrubs grown in desert soil  

SciTech Connect

Desert shrubs - Ambrosia dumosa, Lycium andersonii, Larrea tridenata, and Ephedra nevadensis wre grown in a glasshouse in desert (calcarous) soil with different levels of added Zn, Ni, and Cd. The objective was to study effects of the metals on growth and yield and uptake and translocation of metals in desert plant species which are common in the Mojave Desert (areas of Nevada and southeast California). Zinc and Cd considerably decreased yields of all four species. Yields of E. nevadensis were increased by Ni at 250 and 500 mg/kg applied to desert soil. Ephedra nevadensis was more tolerant of Ni than were the other three desert shrubs. Some interactions were observed among various elements: manganese concentration was increased in shrubs by Zn. Particularly, application of Ni reduced the concentrations of Zn and Mn over the control.

Patel, P.M.; Wallace, A.; Romney, E.M.; Alexander, G.V.

1980-01-01

397

Infiltration Through Desert Pavements, Mojave Desert, CA, USA  

NASA Astrophysics Data System (ADS)

Desert pavements consist of a surface layer of closely packed gravel that overlies thin, gravel-poor vesicular A (Av) soil horizon. Pavements are prominent features in arid and semi-arid environments and can be found on a variety of landforms of significantly diverse ages ranging from Holocene to Tertiary. Well-developed Av profiles form distinct and highly structured prismatic peds. These fine-grained, structured soils can exhibit drastically reduced infiltration rates, rendering some localized areas nearly impermeable and greatly impacting soil development, plant and biota diversity, and groundwater recharge. We sought to study how desert pavement development can impact the hydraulic conductivity characteristics in localized areas (order of 10s of cm). Field sites were chosen at the Mojave Natural Preserve, near Kelso Dunes, CA, USA, which has been the location of considerable prior research by the second author. The sites vary by parent material, clay and silt content, surface age, and variable degree of surface clast cover. Transects were chosen that traversed pavement surfaces of variable development (well developed to poorly developed). Hydraulic conductivity was determined with a tension infiltrometer conducted at different tensions and initial water contents (to better estimate the potential for preferential flow). Sites with dry initial conditions were first analyzed at zero tensions to promote inter-ped flow. After allowing soil peds to hydrate and expand, the tests were run again at a range of soil tensions to promote matrix flow. Differences in saturated conductivities (measured and fitted) were attributed to preferential flow around desiccated peds. Soil texture and structure were measured and described, respectively, allowing for the correlation of conductivity functions to soil surface age and physical characteristics.

Young, M. H.; McDonald, E. V.; Caldwell, T. C.; Benner, S. G.

2003-04-01

398

Anthropogenic enhancement of Egypt's Mediterranean fishery.  

PubMed

The highly productive coastal Mediterranean fishery off the Nile River delta collapsed after the completion of the Aswan High Dam in 1965. But the fishery has been recovering dramatically since the mid-1980s, coincident with large increases in fertilizer application and sewage discharge in Egypt. We use stable isotopes of nitrogen (delta(15)N) to demonstrate that 60%-100% of the current fishery production may be from primary production stimulated by nutrients from fertilizer and sewage runoff. Although the establishment of the dam put Egypt in an ideal position to observe the impact of rapid increases in nutrient loading on coastal productivity in an extremely oligotrophic sea, the Egyptian situation is not unique. Such anthropogenically enhanced fisheries also may occur along the northern rim of the Mediterranean and offshore of some rapidly developing tropical countries, where nutrient concentrations in the coastal waters were previously very low. PMID:19164510

Oczkowski, Autumn J; Nixon, Scott W; Granger, Stephen L; El-Sayed, Abdel-Fattah M; McKinney, Richard A

2009-01-21

399

Tick paralysis: first zoonosis record in Egypt.  

PubMed

Tick paralysis caused by the secretion of toxin with saliva while taking a blood meal is an important veterinary disease, but is rare in humans. Although it has certain geographical proclivities, it exists worldwide. Tick paralysis was demonstrated for the first time in Egypt among four children living in rural area at Giza Governorate. The clinical pictures were confused with rabies; myasthensia gravis; botulism; diphtheritic polyneuropathy encountered in rural areas. The recovery of tick infesting the four little children and negative clinical and laboratory data of all diseases denoted tick paralysis. The encountered ticks infesting their animals were Rhipicephalus sanguineus on dogs, Hyalomma dromedarii on camels and Hyalomma anatolicum excavatum and Haemaphysalis sp. on goats. The case was recognized as first record of tick paralysis in Egypt. PMID:22662597

Mosabah, Amira A Abd El-rahman; Morsy, Tosson A

2012-04-01

400

Holocene woodlands in the southwestern deserts.  

PubMed

Twenty-nine radiocarbon-dated pack rat middens document woodland communities in the deserts of the southwestern United States less than 10,000 years ago. A synchronous change from woodland to desert or grassland occurred about 8000 years ago in the Chihuahuan, Sonoran, and Mohave deserts. A shift of the Aleutian low and the winter storm track to the north, which resulted in drastically reduced winter precipitation in these areas, is inferred. The shift to nonpluvial climates in the Southwest lagged behind the beginning of nonglacial climates in the North because the melting continental glaciers contined to affect general circulation patterns. PMID:17755362

VAN Devender, T R

1977-10-14

401

Towards a Precise Geoid for Egypt  

Microsoft Academic Search

An optimal procedure to merge all cur- rently available free-air gravity anomalies in Egypt and neighbouring countries (both on land and sea) has been carried out. As a result, we obtain a set of gravity anomalies representing the gravimet- ric data set for this investigation. In the framework of the well-known remove-restore technique, a set of 3000£ 3000 and 30£

Hussein A. Abd-Elmotaal

1999-01-01

402

Seismicity and kinematic evolution of middle Egypt  

NASA Astrophysics Data System (ADS)

Based on historical and instrumental seismicity as well as recent GPS measurements, the seismicity and kinematic evaluation of middle Egypt is presented. Middle Egypt suffered in historical times by six major earthquakes and the Ramses II temple on the west bank of the Nile in Luxor, was almost destroyed by an ancient event. The temporal distribution of recent earthquakes (1900 1997) is highly scattered with only nine events recorded. Only after the installation of the modern Egyptian national seismograph network (ENSN) the seismic record of middle Egypt increased with a total of 280 earthquakes from 1998 to 2004. Focal mechanism solutions of the largest five events during the ENSN's operation period reveal reverse faulting mechanism with minor strike-slip component on the west bank of the Nile, while a normal faulting mechanism dominate in the eastern side. The orientations of both P- and T-axes are consistent with the Red Sea-Gulf of Suez stress field. Dynamic source parameters of these five events were derived from P-wave spectra as well. Three campaigns of GPS measurements were carried out for the middle Egypt network that established after the first instrumental earthquake on 14 December 1998 in this area. The velocity vectors for each epoch of observations were calculated and deformation analysis was performed. The horizontal velocity varies between 1 and 4 mm/year across the network. The deformation pattern suggests significant contraction across the southeastern sector of the study area while, the northwestern part is characterized by an extension strain rates. High shear strain is observed along the epicenteral area of the Mw = 4.0 June 2003 earthquake possibly reflecting the stress accumulation stage of a seismic cycle.

Badawy, A.; Abdel-Monem, S. M.; Sakr, K.; Ali, Sh. M.

2006-08-01

403

Ostrich ( Struthio camelus ) production in Egypt  

Microsoft Academic Search

This review discusses the historical, developmental and practices of ostrich farming in Egypt. In the early 20th century,\\u000a ostrich farming was very important for production of ostrich feathers and documents were produced to perfect the art of procuring\\u000a the plumes from the birds and subsequently processing them. Pharaohs used ostrich feathers for adornment. Of 43 provinces,\\u000a 12 were featured in

R. G. Cooper; Kh. M. A. Mahrose; M. El-Shafei; I. F. M. Marai

2008-01-01

404

Water use, productivity and interactions among desert plants. Final report  

SciTech Connect

On the Colorado Plateau, precipitation comes either from winter storms generated in the Gulf of Alaska or from summer convection storms generated by the Arizona monsoon system. Understanding the current seasonal and regional patterns of precipitation inputs into an ecosystem has ramifications at several levels: on carbon and mineral cycling at the ecosystem level, on biodiversity at the community level, and on productivity and adaptation at the population and species levels. The interior deserts of Arizona, Nevada, and Utah represent the driest regions of western North America, resulting from a combination of rainshadow effects and either the southern limits of winter moisture input or the northern limits of summer moisture input or both. Shifts in strengths of storm-generating conditions in the Pacific and in the Gulf influence both the magnitude and seasonality of soil moisture availability and therefore constrain periods of primary productivity activity in these aridland ecosystems. One major consequence predicted by global climate change scenarios is a change in monsoonal (summer) precipitation; it will increase in some areas and decrease in others. A second is increased soil temperatures and increased interior drought associated with ocean-land temperature disequilibrium. This project focused on the influence of variations in summer moisture input on structure-function relationships within a cold desert ecosystem on the Colorado Plateau. The primary field sites were located at Stud Horse Point, Utah, located on the Utah-Arizona boundary in the Glen Canyon National Recreation Area and at the Arizona monsoon boundary region.

Ehleringer, J.R.

1996-09-01

405

Multiroute memories in desert ants  

PubMed Central

When offered a permanent food source, central Australian desert ants, Melophorus bagoti, develop individually distinct, view-based foraging routes, which they retrace with amazing accuracy during each foraging trip. Using a particular channel setup connected to an artificial feeder, we trained M. bagoti ants to either two or three inward routes that led through different parts of their maze-like foraging grounds. Here, we show that ants are able to adopt multiple habitual paths in succession and that they preserve initially acquired route memories even after they have been trained to new routes. Individual ants differ in the consistency with which they run along habitual pathways. However, those ants that follow constant paths retain their route-specific memories for at least 5 days of suspended foraging, which suggests that even multiple route memories, once acquired, are preserved over the entire lifetime of a forager.

Sommer, Stefan; von Beeren, Christoph; Wehner, Rudiger

2008-01-01

406

Stranded on a Desert Island  

NSDL National Science Digital Library

In this activity, learners are stranded on a tropical desert island. At an abandoned science lab on the island, they explore the properties of different materials to determine which are best to construct a shelter, boat, and path to aid in their survival. The properties investigated are: magnetism, conductivity, opacity, buoyancy, and elasticity. Learners practice research techniques, must work together, and need to design within constraints. This lesson plan includes definitions of key words, scenario sheet, lab sheets,and handouts. This activity is the third in a four part series of pre/post activities (Matter, Matter, What's the Matter?) created for an exhibit on material science, but can be used on its own.

Houston, Children'S M.

2009-01-01

407

Desert potholes: Ephemeral aquatic microsystems  

USGS Publications Warehouse

An enigma of the Colorado Plateau high desert is the "pothole", which ranges from shallow ephemeral puddles to deeply carved pools. The existence of prokaryotic to eukaryotic organisms within these pools is largely controlled by the presence of collected rainwater. Multivariate statistical analysis of physical and chemical limnologic data variables measured from potholes indicates spatial and temporal variations, particularly in water depth, manganese, iron, nitrate and sulfate concentrations and salinity. Variation in water depth and salinity are likely related to the amount of time since the last precipitation, whereas the other variables may be related to redox potential. The spatial and temporal variations in water chemistry affect the distribution of organisms, which must adapt to daily and seasonal extremes of fluctuating temperature (0-60 ??C), pH changes of as much as 5 units over 12 days, and desiccation. For example, many species become dormant when potholes dry, in order to endure intense heat, UV radiation, desiccation and freezing, only to flourish again upon rehydration. But the pothole organisms also have a profound impact on the potholes. Through photosynthesis and respiration, pothole organisms affect redox potential, and indirectly alter the water chemistry. Laboratory examination of dried biofilm from the potholes revealed that within 2 weeks of hydration, the surface of the desiccated, black biofilm became green from cyanobacterial growth, which supported significant growth in heterotrophic bacterial populations. This complex biofilm is persumably responsible for dissolving the cement between the sandstone grains, allowing the potholes to enlarge, and for sealing the potholes, enabling them to retain water longer than the surrounding sandstone. Despite the remarkable ability of life in potholes to persist, desert potholes may be extremely sensitive to anthropogenic effects. The unique limnology and ecology of Utah potholes holds great scientific value for understanding water-rock-biological interactions with possible applications to life on other planetary bodies. ?? Springer 2005.

Chan, M. A.; Moser, K.; Davis, J. M.; Southam, G.; Hughes, K.; Graham, T.

2005-01-01

408

Desert dust satellite retrieval intercomparison  

NASA Astrophysics Data System (ADS)

This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify and understand the differences between current algorithms, and hence improve future retrieval algorithms. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as assumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, at least as significant as these differences are sampling issues related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset.

Carboni, E.; Thomas, G. E.; Sayer, A. M.; Siddans, R.; Poulsen, C. A.; Grainger, R. G.; Ahn, C.; Antoine, D.; Bevan, S.; Braak, R.; Brindley, H.; Desouza-Machado, S.; Deuzé, J. L.; Diner, D.; Ducos, F.; Grey, W.; Hsu, C.; Kalashnikova, O. V.; Kahn, R.; North, P. R. J.; Salustro, C.; Smith, A.; Tanré, D.; Torres, O.; Veihelmann, B.

2012-01-01

409

Behind desert storm; The new military paradigm  

SciTech Connect

The author discusses US foreign policy in light of Operation Desert Storm. Near-future military technology is discussed, including: strategic weapons, advanced missile systems, and satellite defense communication systems.

Klare, M.T. (Hampshire Coll., Amherst, MA (United States))

1991-05-01

410

Operation Desert Storm Environmental Monitoring Ammunition Temperatures.  

National Technical Information Service (NTIS)

The U.S. Army Defense Ammunition Center and School (USADACS), Validation Engineering Division (SMCAC-DEV), monitored ammunition temperatures within Saudi Arabia (SA) for a period of approximately two months in support of Operation Desert Storm. The SMCAC-...

W. R. Meyer

1990-01-01

411

Behind desert storm; The new military paradigm  

Microsoft Academic Search

The author discusses US foreign policy in light of Operation Desert Storm. Near-future military technology is discussed, including: strategic weapons, advanced missile systems, and satellite defense communication systems.

Klare

1991-01-01

412

Education in Egypt and Egyptian response to eclipses  

Microsoft Academic Search

Astronomy and space science educations started in Egypt at the university level since 1939 at Department of Astronomy and Meteorology, Cairo University. Undergraduate and graduate education in Egypt will be discussed in this work. About 15 students yearly obtain their PhD degrees in Astronomy from the Egyptian universities. Seven International groups under my supervision have done the total solar Eclipse

A. Hady

2006-01-01

413

Space science education in Egypt and the 2006 solar eclipse  

Microsoft Academic Search

The space science research has been started in Egypt since 1910 by measuring the solar constant as indication of solar radiation at Helwan Observatory. The solar sunspot studies and its influence on the Nile flooding was erected and operated at Helwan as a first solar station in Egypt during 1957. Zeiss-Coude’ refractor was installed in 1964. Astronomy and space science

A. A. Hady

2008-01-01

414

Radical Changes in the Muslim World: Turkey, Iran, Egypt  

Microsoft Academic Search

This piece engages with contemporary revolutions from the perspective of religion. Religion has played a significant role in mobilizing peoples in Turkey, Iran, and even Egypt. I examine the Arab spring by suggesting that these movements point to radical changes in the Muslim World by paying close attention to revolutions in Turkey, Iran, and Egypt. I argue that religion has acted

Fred Dallmayr

2011-01-01

415

The Fleas (Siphonaptera) of Egypt. Early Records from Mammals.  

National Technical Information Service (NTIS)

Sixteen species of fleas are recorded from 19 species of mammals in Egypt. Nearly all specimens were collected in a 1946-1947 parasite survey under the auspices of NAMRU-3. Three flea-host associations are reported as new for Egypt. (Author)

G. E. Hass P. Q. Tomich

1973-01-01

416

Separate but Equal: Segregated Religious Education in Egypt's Public Schools  

ERIC Educational Resources Information Center

|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…

Isaac, John

2012-01-01

417

Power and Gender in Ancient Egypt: The Case of Hatshepsut  

ERIC Educational Resources Information Center

|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,…

Hilliard, Kristina; Wurtzel, Kate

2009-01-01

418

Weathering damage on Pharaonic sandstone monuments in Luxor-Egypt  

Microsoft Academic Search

The Pharaonic stone monuments in Upper Egypt represent cultural heritage of outstanding universal value. All monuments have suffered weathering damage. In the year 2000 an Egyptian–German research co-operation was started aiming at the systematic investigation of stone weathering on the historical monuments in Upper Egypt as a contribution to monument preservation. Pilot studies were carried out on the Karnak Temple

Bernd Fitzner; Kurt Heinrichs; Dennis La Bouchardiere

2003-01-01

419

Borate in mummification salts and bones from Pharaonic Egypt  

Microsoft Academic Search

Mummification processes in Pharaonic Egypt were successful using sodium salts. Quite frequently sodium concentrations in mummified bones ranged from 300 to 4000 ?mol\\/g. In the search for an effective inorganic conservation compound our choice fell on boric acid. The possible presence of borate in mummification salts used in Pharaonic Egypt was of special interest both historically and biochemically. In two

Yoka Kaup; Mirjam Schmid; Andrew Middleton; Ulrich Weser

2003-01-01

420

Resource Unit on Egypt for the Intermediate Grades.  

ERIC Educational Resources Information Center

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,…

Husbands, Kenneth; Taylor, Bob

421

Ancient mythology versus eternal reality : judgments upon Egypt  

Microsoft Academic Search

With the vast number of Egyptian deities and the seemingly strange nature of some of the plagues, how were all of the gods of Egypt judged through only ten plagues? In order to see any correspondence of plagues to gods, something of the essence of the religion of Egypt must be grasped. That essence is bound up in the Egyptian

Robert Kirk Kilpatrick

1993-01-01

422

Satellite observations of desert dust-induced Himalayan snow darkening  

NASA Astrophysics Data System (ADS)

The optically thick aerosol layer along the southern edge of the Himalaya has been subject of several recent investigations relating to its radiative impacts on the South Asian summer monsoon and regional climate forcing. Prior to the onset of summer monsoon, mineral dust from southwest Asian deserts is transported over the Himalayan foothills on an annual basis. Episodic dust plumes are also advected over the Himalaya, visible as dust-laden snow surface in satellite imagery, particularly in western Himalaya. We examined spectral surface reflectance retrieved from spaceborne MODIS observations that show characteristic reduction in the visible wavelengths (0.47 µm) over western Himalaya, associated with dust-induced solar absorption. Case studies as well as seasonal variations of reflectance indicate a significant gradient across the visible (0.47 µm) to near-infrared (0.86 µm) spectrum (VIS-NIR), during premonsoon period. Enhanced absorption at shorter visible wavelengths and the resulting VIS-NIR gradient is consistent with model calculations of snow reflectance with dust impurity. While the role of black carbon in snow cannot be ruled out, our satellite-based analysis suggests the observed spectral reflectance gradient dominated by dust-induced solar absorption during premonsoon season. From an observational viewpoint, this study underscores the importance of mineral dust deposition toward darkening of the western Himalayan snow cover, with potential implications to accelerated seasonal snowmelt and regional snow albedo feedbacks.

Gautam, Ritesh; Hsu, N. Christina; Lau, William K.-M.; Yasunari, Teppei J.

2013-03-01

423

Adaptive Mechanisms of Halophytes in Desert Regions  

Microsoft Academic Search

Plants growing in desert regions have to face a number of environmental adversaries such as high temperature, soil salinity\\u000a and water stress due to low precipitation. Halophytes are among the successful plants that grow in desert saline regions.\\u000a Halophytes use many different strategies to survive under these conditions. Some halophytes seeds can germinate in the presence\\u000a of high salinity. Seeds

D. J. Weber

424

North American Desert Microbiotic Soil Crust Communities  

Microsoft Academic Search

Deserts are defined in a classic paper by Noy-Meir (1973) as “water-controlled ecosystems with infrequent, discrete, and largely\\u000a unpredictable water inputs.” They are found to a greater or lesser extent on all six continents (including Antarctica). Based\\u000a on the moisture index system of Thornthwaite (1948), Meigs (1953) divided deserts into three categories: extremely arid (less\\u000a than 60–100 mm mean annual

Valerie R. Flechtner

425

Impact of the Desert dust on the summer monsoon system over Southwestern North America  

NASA Astrophysics Data System (ADS)

The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995-2009). During the monsoon season, dust has a cooling effect (-0.90 W m-2) at the surface, a warming effect (0.40 W m-2) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (-0.50 W m-2) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day-1 over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to ~40 % over the eastern slope of the Mountains (Arizona-New~Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the mega-drought conditions projected for the future.

Zhao, C.; Liu, X.; Leung, L. R.

2012-04-01

426

Impact of the Desert Dust on the Summer Monsoon System over Southwestern North America  

SciTech Connect

The radiative forcing of dust emitted from the Southwest United States (US) deserts and its impact on monsoon circulation and precipitation over the North America monsoon (NAM) region are simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem) for 15 years (1995-2009). During the monsoon season, dust has a cooling effect (-0.90 W m{sup -2}) at the surface, a warming effect (0.40 W m{sup -2}) in the atmosphere, and a negative top-of-the-atmosphere (TOA) forcing (-0.50 W m{sup -2}) over the deserts on 24-h average. Most of the dust emitted from the deserts concentrates below 800 hPa and accumulates over the western slope of the Rocky Mountains and Mexican Plateau. The absorption of shortwave radiation by dust heats the lower atmosphere by up to 0.5 K day{sup -1} over the western slope of the Mountains. Model sensitivity simulations with and without dust for 15 summers (June-July-August) show that dust heating of the lower atmosphere over the deserts strengthens the low-level southerly moisture fluxes on both sides of the Sierra Madre Occidental. It also results in an eastward migration of NAM-driven moisture convergence over the western slope of the Mountains. These monsoonal circulation changes lead to a statistically significant increase of precipitation by up to {approx}40% over the eastern slope of the Mountains (Arizona-New Mexico-Texas regions). This study highlights the interaction between dust and the NAM system and motivates further investigation of possible dust feedback on monsoon precipitation under climate change and the megadrought conditions projected for the future.

Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.

2012-04-24

427

Genetic linkage between the Yellow River, the Mu Us desert and the Chinese Loess Plateau  

NASA Astrophysics Data System (ADS)

Arid and semi arid northern China holds some of the world's most significant sand sea and loess deposits. In particular, arguably the most important late Cenozoic wind-blown dust archives on land are exposed on the Chinese Loess Plateau. The origin of this loess-forming dust and its relationship to adjacent sand seas is unclear and has been the subject of considerable debate. Polarization of opinion over the sources of loess also reflects uncertainty over its relationship to large river systems and to the sources of proximal desert sands. It is critical to resolve this in order to elucidate the origins of sand seas, to determine the activity of past dust emitting regions and to fully exploit loess climate archives. Here we combine zircon U–Pb, fission-track and double dating with heavy mineral analysis to test the role of proximal deserts and rivers in contributing dust to the Loess Plateau. We focus on the Mu Us desert to test hypotheses over its sediment sources and because previous studies have often presented contrasting interpretations over its importance as a loess source. Spatial complexity of zircon ages and heavy mineral assemblages in Mu Us sand rules out significant aeolian mixing and shows that grains originating in northern Tibet dominate in the western Mu Us, with local sources dominating in the east of the desert. The western Mu Us far-travelled grains are shown to be delivered by the Yellow River and associated systems. Crucially, the western Mu Us grains and Yellow River grains show U–Pb age distributions and heavy mineral assemblages virtually identical to those of the Quaternary loess. Thus, our results demonstrate that the Yellow River and associated systems transports large quantities of sediment from northern Tibet to the Mu Us desert and further suggest that the river contributes a significant volume of material to the Loess Plateau. This provides the first evidence of a genetic link between the Yellow River and formation of the Chinese Loess Plateau and suggests a greater role for fluvial activity in past dust and desert sand sea formation.

Stevens, T.; Carter, A.; Watson, T. P.; Vermeesch, P.; Andò, S.; Bird, A. F.; Lu, H.; Garzanti, E.; Cottam, M. A.; Sevastjanova, I.

2013-10-01

428

Indirect determination of broadband turbidity coefficients over Egypt  

NASA Astrophysics Data System (ADS)

Long-term data from diffuse and global irradiances were used to calculate direct beam irradiance which was used to determine three atmospheric turbidity coefficients (Linke T L , Ångström ? and Unsworth-Monteith ? a ) at seven sites in Egypt in the period from 1981 to 2000. Seven study sites (Barrani, Matruh, Arish, Cairo, Asyut, Aswan and Kharga) have been divided into three categories: Mediterranean climate (MC), desert Nile climate (DNC) and urban climate (UC, Cairo). The indirect method (i.e., global irradiance minus diffuse irradiance) used here allows to estimate the turbidity coefficients with an RMSE% ?20 % (for ?, ? a and T L ) and ~30 % (for ?) if compared with those estimated by direct beam irradiance and sunphotometeric data, respectively. Monthly averages of T L , ? and ? a show seasonal variations with mainly maxima in spring at all stations, due to Khamsin depressions coming from Sahara. Secondary maxima is observed in summer and autumn at DNC and MC (Barrani and Arish) stations in summer due to dust haze which prevails during that season and at UC (Cairo) in autumn, due to the northern extension of the Sudan monsoon trough, which is accompanied by small-scale depressions with dust particles. The mean annual values of ?, ? a , and T L (0.216, 0.314, and 4.6, respectively) are larger in Cairo than at MC stations (0.146, 0.216, and 3.8, respectively) and DNC stations (0.153, 0.227, and 3.8, respectively). Both El-Chichon and Mt. Pinatubo eruptions were examined for all records data at MC, UC and DNC stations. The overburden caused by Mt. Pinatubo's eruption was larger than El-Chichon's eruption and overburden for ?, and T L at DNC stations (0.06, and 0.58 units, respectively) was more pronounced than that at MC (0.02, and 0.26, respectively) and UC (0.05 and 0.52 units, respectively) stations. The annual variations in wind speed and turbidity parameters show high values for both low and high wind speed at all stations. The wind directions have a clear effect on atmospheric turbidity, and consequently, largest turbidities occur when the wind carries aerosols from the main particle sources, such as industrial particle sources around Cairo or to some extent from the Sahara surrounding all study stations.

El-Metwally, Mossad

2012-10-01

429

Indirect determination of broadband turbidity coefficients over Egypt  

NASA Astrophysics Data System (ADS)

Long-term data from diffuse and global irradiances were used to calculate direct beam irradiance which was used to determine three atmospheric turbidity coefficients (Linke T L , Ångström ? and Unsworth-Monteith ? a ) at seven sites in Egypt in the period from 1981 to 2000. Seven study sites (Barrani, Matruh, Arish, Cairo, Asyut, Aswan and Kharga) have been divided into three categories: Mediterranean climate (MC), desert Nile climate (DNC) and urban climate (UC, Cairo). The indirect method (i.e., global irradiance minus diffuse irradiance) used here allows to estimate the turbidity coefficients with an RMSE% ?20 % (for ?, ? a and T L ) and ~30 % (for ?) if compared with those estimated by direct beam irradiance and sunphotometeric data, respectively. Monthly averages of T L , ? and ? a show seasonal variations with mainly maxima in spring at all stations, due to Khamsin depressions coming from Sahara. Secondary maxima is observed in summer and autumn at DNC and MC (Barrani and Arish) stations in summer due to dust haze which prevails during that season and at UC (Cairo) in autumn, due to the northern extension of the Sudan monsoon trough, which is accompanied by small-scale depressions with dust particles. The mean annual values of ?, ? a , and T L (0.216, 0.314, and 4.6, respectively) are larger in Cairo than at MC stations (0.146, 0.216, and 3.8, respectively) and DNC stations (0.153, 0.227, and 3.8, respectively). Both El-Chichon and Mt. Pinatubo eruptions were examined for all records data at MC, UC and DNC stations. The overburden caused by Mt. Pinatubo's eruption was larger than El-Chichon's eruption and overburden for ?, and T L at DNC stations (0.06, and 0.58 units, respectively) was more pronounced than that at MC (0.02, and 0.26, respectively) and UC (0.05 and 0.52 units, respectively) stations. The annual variations in wind speed and turbidity parameters show high values for both low and high wind speed at all stations. The wind directions have a clear effect on atmospheric turbidity, and consequently, largest turbidities occur when the wind carries aerosols from the main particle sources, such as industrial particle sources around Cairo or to some extent from the Sahara surrounding all study stations.

El-Metwally, Mossad

2013-01-01

430

First Ladies' Symposium on Early Childhood in Egypt (Cairo, Egypt, May 21, 2001).  

ERIC Educational Resources Information Center

|This document is comprised of the papers presented at the First Ladies' Symposium on Early Childhood in Egypt in May 2001. Participating in the symposium were representatives from the World Bank, the Amsterdam Institute for International Development, the Children's Project, and the Academy for Educational Development. The symposium opened with an…

O'Gara, Chloe

431

First Ladies' Symposium on Early Childhood in Egypt (Cairo, Egypt, May 21, 2001).  

ERIC Educational Resources Information Center

This document is comprised of the papers presented at the First Ladies' Symposium on Early Childhood in Egypt in May 2001. Participating in the symposium were representatives from the World Bank, the Amsterdam Institute for International Development, the Children's Project, and the Academy for Educational Development. The symposium opened with an…

O'Gara, Chloe

432

Operation Desert Shield/Desert Storm Ready Reserve Force Activation Analysis.  

National Technical Information Service (NTIS)

An analysis of the activation of the first 45 Ready Reserve Force (RRF) vessels activated by the Maritime Administration to support of Operation DESERT SHIELD/DESERT STORM. This report addresses the time sequencing of the RRF vessels and their material co...

R. Butcher H. Cougan R. Giblon R. Kiefer J. Schaff

1991-01-01

433

Analysis of United States Marine Corps Contracting During Operations Desert Shield and Desert Storm.  

National Technical Information Service (NTIS)

The purpose of this study was to document United States Marine Corps contracting and procurement activities during Operations Desert Shield and Desert Storm. This was accomplished by examining who was there, how they were organized, and in what type of ac...

G. R. Caldwell

1995-01-01

434

Total Force: The Reserve Recall Process and Desert Shield/Desert Storm.  

National Technical Information Service (NTIS)

The purpose of this thesis is to examine the Desert Shield/Desert Storm reserve recall process in the context of the past and future of the Total Force Plan. The thesis provides an overview of the evolution of the Total Force Plan since its inception in 1...

D. L. Moore

1991-01-01

435

Heavy metal contamination from historic mining in upland soil and estuarine sediments of Egypt Bay, Maine, USA  

Microsoft Academic Search

Concentrations of Cd, Cu, Pb and Zn in sediments of Egypt Bay in Hancock County, Maine, are elevated above background levels. The source of the contamination is Cu mining that occurred in the uplands adjacent to Egypt Stream between 1877 and 1885. Egypt Stream is a tributary to Egypt Bay. Egypt Bay is part of the Taunton Bay estuary system.

L. J. Osher; L. Leclerc; G. B. Wiersma; C. T. Hess; V. E. Guiseppe

2006-01-01

436

An extended field of crater-shaped structures in the Gilf Kebir region, Egypt: Observations and hypotheses about their origin  

Microsoft Academic Search

Using satellite imagery, we detected more than 1300 small crater-like structures distributed over an area of 40,000km2 in the Western Egyptian Desert, close to the Gilf Kebir plateau. Sixty-two of them were visited in the field, and morphological observations, rock samples and ground-penetrating radar data were obtained. After presenting our fieldwork results, we discuss two hypotheses for their origin: hydrothermal

Philippe Paillou; Bruno Reynard; Jean-Marie Malézieux; Jean Dejax; Essam Heggy; Pierre Rochette; Wolf Uwe Reimold; Patrick Michel; David Baratoux; Philippe Razin; Jean-Paul Colin

2006-01-01

437

Regional and Seasonal Diet of the Western Burrowing Owl in South-Central Nevada  

SciTech Connect

We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.

Derek B. Hall, Paul D. Greger, Jeffrey R. Rosier

2009-04-01

438

Desert blooms - at a price  

Microsoft Academic Search

This is the second in a two-part series on the economic and environmental effects of water use in the arid lands of the western US. It examines four specific areas differing in size and terrain: southwestern Arizona's Wellton-Mohawk Irrigation District, California's San Joaquin Basin, south central Arizona's Santa Cruz Basin, and Gaines County on the Great Plains. The one characteristic

1981-01-01

439

Solid Waste and Public Clean-Up Project Governorate of Alexandria, Egypt. Report No. 5: Privatizing Solid Waste Management Services. A Summary Guide for the Governorates of Egypt.  

National Technical Information Service (NTIS)

Solid waste management is one of the most serious and difficult to solve environmental problems existing in Egypt. Like so many developing countries around the globe, Egypt is being overwhelmed by solid waste generated from various sectors including resid...

2001-01-01

440

Elsheimer, Galileo, and The Flight into Egypt  

NASA Astrophysics Data System (ADS)

Elsheimer's The Flight into Egypt is famous as the first apparently naturalistic rendering of the night sky. It was painted at almost exactly the same date as the invention of the telescope and predated Galileo's discoveries described in his Sidereus Nuncius of 1610. This paper, a follow-up to that of Howard (1992), discusses the history of the discovery of the telescope through this period and assesses how realistically Elsheimer depicted the sky. It is argued that the sky was not one that Elsheimer could ever have seen and that the painting is more a religious iconographic text than an accurate representation of the sky.

Howard, D.; Longair, M. S.

2011-06-01

441

Egypt site of first CSM marketing audit.  

PubMed

The 1st application of the marketing audit concept to a CSM project was implemented in Egypt's Family of the Future (FOF) contraceptive social marketing program in 1982. The audit defined the basic mission of the FOF as one of assisting the government in achieving its long range family planning goals. The stated FOF objectives are as follows: to create an awareness or an increase in demand for family planning services, particularly among the lower socioeconomic strata in urban Egypt; to establish and maintain a reliable supply mechanism to make FOF products more readily acceptable and available from pharmacies; and to consolidate the CSM operations and services first in the greater Cairo area and then expand to other urban areas in Egypt. The core strategy of the FOF incorporates several elements, including intensive media based advertising and personal promotion to promote the concept of family planning and to educate the general public about contraceptive alternatives. FOF product prices are considerably lower than commercial prices. Dr. Alan R. Andreasen, who conducted the audit on behalf of the FOF technical assistance contractor, noted that the FOF is growing rapidly and stated that the audit recommendations were intended to help FOF management. Dr. Andreasen conducted interviews with all the senior personnel at FOF and met with various specialized staff members such as the Public Relations Manager. Dr. Andreasen noted that at the time of the audit the FOF could claim major accomplishments in creating an awareness of the need for family planning and in product sales. From the time products were launched in 1979 through 1981 condom sales increased 260%. Foaming tablet sales increased more than 320% and IUD sales increased nearly 330%. The introduction of the Copper 7 IUD accounted for 35% of the growth of IUD sales in 1981. Couple years of protection (CYP) provided by all products increased from 45,533 in 1979 to 190,831 in 1981, an increase over 300%. The pharmacy study results indicated that FOF medical representatives are very effective, and there are no major complaints about overloaded inventories or neglect on the part of FOF representatives. Andreasen recommends that "commercial orientation be allowed to dominate in the future..." An audit planned in Egypt for late summer 1983 will focus on results and activities of geographic expansion, preparations to introduce an oral contraceptive, and implementation of new management techniques. PMID:12279587

1982-01-01

442

Perceived night length ratios in ancient Egypt  

NASA Astrophysics Data System (ADS)

The first record we have of a seasonal night length ratio for Egypt is from the mid 16th century BC. The origin of this estimate is traced to observations made three centuries previously, and the later reinterpretation and instrumental use of this ratio is traced down to 100AD. Extended comment is made on the astronomical dating involved in this description of events, and an attempt is made to reconstruct the alleged confirmation (or calibration) of the new timepiece that plays a central part in the story. It is believed that this is the earliest example of this fundamental scientific practice on record.

Fermor, John

443

NASA Desert RATS 2011 Education Pilot Project and Classroom Activities  

NASA Astrophysics Data System (ADS)

For the 2011 NASA Desert RATS analog activities, NASA HQ provided support to develop an education pilot project with student activities to parallel the Desert RATS mission planning and exploration activities in the classroom, as well as educator training.

Gruener, J. E.; McGlone, M.; Allen, J.; Tobola, K.; Graff, P.

2012-03-01

444

Desert Bighorn Sheep: A Guide to Selected Management Practices,  

National Technical Information Service (NTIS)

The guide summarizes pertinent literature on four topics of desert bighorn sheep ecology and management: (1) their water requirements and adaptations are compared with those of other desert-dwelling ungulates; (2) the effects of human activities such as m...

N. S. Smith P. R. Krausman

1988-01-01

445

Lut Desert (Iran): A High - Potential Area for Finding Meteorites  

NASA Astrophysics Data System (ADS)

Field trips to the Lut desert in recent years have led to the discovery of several fragments of meteorites. Climate and surface conditions in Lut desert makes it a high-potential region for preserving large concentrations of meteorites.

Pourkhorsandi, H.; Mirnejad, H.

2013-09-01

446

Psychological Preparation for Monotonous Activity under Desert Conditions. (Abstract Only).  

National Technical Information Service (NTIS)

Psychological characteristics of individual reactions in adaptation to desert conditions were studied in order to develop methodology for psychological preparation for crossing the Karakuma desert on foot. The studies were performed in two phases: during ...

V. F. Sopov

1988-01-01

447

Effects of water deprivation on urea metabolism in camels, desert sheep and desert goats fed dry desert grass.  

PubMed

1. The effects of water restriction and complete water deprivation on nitrogen retention and urea recycling were examined in camels, desert sheep and desert goats fed only dry desert grass of 3.2% crude protein content. 2. All three species were in negative nitrogen balance when water was available ad libitum. 3. In camels urea recycling was consistently high (94-97%) and nitrogen balance did not change with treatment. 4. In sheep and goats urea recycling increased from 75% to 94% (sheep) and from 79% to 95% (goats) during water deprivation, and nitrogen balance improved to positive values. 5. In all species water deprivation depressed dry matter intake and increased apparent digestibility of dry matter and nitrogen. 6. The effects of water restriction were generally intermediate. 7. These results suggest that nitrogen metabolism in adult domestic livestock raised by nomadic pastoralists in Sudan is not harmed, and may in fact be improved by short periods of water deprivation. PMID:6132716

Mousa, H M; Ali, K E; Hume, I D

1983-01-01

448

Modeling the Spatial Spread of Rift Valley Fever in Egypt  

PubMed Central

Rift Valley fever (RVF) is a severe viral zoonosis in Africa and the Middle East that harms both human health and livestock production. It is believed that RVF in Egypt has been repeatedly introduced by the importation of infected animals from Sudan. In this paper, we propose a three-patch model for the process by which animals enter Egypt from Sudan, are moved up the Nile, and then consumed at population centers. The basic reproduction number for each patch is introduced and then the threshold dynamics of the model are established. We simulate an interesting scenario showing a possible explanation of the observed phenomenon of the geographic spread of RVF in Egypt.

Gao, Daozhou; Cosner, Chris; Cantrell, Robert Stephen; Beier, John C.; Ruan, Shigui

2013-01-01

449

Lake-desert evolution during Holocene in Ulan Buh Desert, China  

NASA Astrophysics Data System (ADS)

Ulan Buh desert locates at the northwest China with an area of ~10,000 Km2, surrounded by Yellow River (east), Langshan Mountain (north), Bayan Urals Mountain (west), and Helan Mountian (south). The desert in the north is just adjacent to the Hetao Plain, an important historical site along the boundary of Han nation and northern minorities in ancient China. Human being activity has been strong in this area since then. It has scientific significance of tracking the desert evolution process during Holocene in this area. Optical stimulated luminescence (OSL) dating was applied to a series of aeolian sand-lacustrine deposit sequences that are distributed in north part of Ulan Buh Desert. Differential GPS measurements were collected to obtain the accurate elevation of these lacustrine remains. The dating results show that these lacustrine remains have almost same deposit sequence, same elevation and same deposit age, indicating the fact that these lacustrine remains belonged to a paleolake which covered the entire northern part of Ulan Buh Desert. Aeolian activities continued from early Holocene till about 8.3ka, and the mega Ulan Buh paleolake covered northern parts of the desert from 8.3 to 7.0ka. Since then, the paleolake shrank and broke into parts after about 6.5ka ago, and the environmental driving force switched back to aeolian activities again. The formation of modern Ulan Buh Desert is found to be synchronous with the disappearance of the paleolake.

Zhao, H.; Li, G.; Chen, F.; Jin, M.

2010-12-01

450

Ploidy race distributions since the Last Glacial Maximum in the North American desert shrub, Larea tridentata  

USGS Publications Warehouse

1. A classic biogeographic pattern is the alignment of diploid, tetraploid and hexaploid races of creosote bush (Larrea tridentata) across the Chihuahuan, Sonoran and Mohave Deserts of western North America. We used statistically robust differences in guard cell size of modern plants and fossil leaves from packrat middens to map current and past distributions of these ploidy races since the Last Glacial Maximum (LGM). 2 Glacial/early Holocene (26a??10 14C kyr bp or thousands of radiocarbon years before present) populations included diploids along the lower Rio Grande of west Texas, 650 km removed from sympatric diploids and tetraploids in the lower Colorado River Basin of south-eastern California/south-western Arizona. Diploids migrated slowly from lower Rio Grande refugia with expansion into the northern Chihuahuan Desert sites forestalled until after ~4.0 14C kyr bp. Tetraploids expanded from the lower Colorado River Basin into the northern limits of the Sonoran Desert in central Arizona by 6.4 14C kyr bp. Hexaploids appeared by 8.5 14C kyr bp in the lower Colorado River Basin, reaching their northernmost limits (~37A?N) in the Mohave Desert between 5.6 and 3.9 14C kyr bp. 3 Modern diploid isolates may have resulted from both vicariant and dispersal events. In central Baja California and the lower Colorado River Basin, modern diploids probably originated from relict populations near glacial refugia. Founder events in the middle and late Holocene established diploid outposts on isolated limestone outcrops in areas of central and southern Arizona dominated by tetraploid populations. 4 Geographic alignment of the three ploidy races along the modern gradient of increasingly drier and hotter summers is clearly a postglacial phenomenon, but evolution of both higher ploidy races must have happened before the Holocene. The exact timing and mechanism of polyploidy evolution in creosote bush remains a matter of conjecture.

Hunter, Kimberly L.; Betancourt, Julio L.; Riddle, Brett R.; Van Devender, Thomas R.; Cole, K. L.; Spaulding, W. G.

2001-01-01

451

Lessons in Combat Service Support Tactical Mobility: The Afghanistan Conflict, Falklands War and Operation Desert Shield/Desert Storm.  

National Technical Information Service (NTIS)

This monograph examines lessons in combat service support (CSS) tactical mobility during the Afghanistan Conflict, the Falklands War, and Operation Desert Shield/Desert Storm. The unique environments of these operations have significant differences in ter...

C. D. Clair

1993-01-01

452

Chapter 3: neurology in ancient Egypt.  

PubMed

Neurology, in the modern sense, did not exist in ancient Egypt, where medicine was a compound of natural, magical and religious elements, with different practitioners for each form of healing. Nevertheless, Egyptian doctors made careful observations of illness and injury, some of which involved the nervous system. Modern scholars have three sources of information about Egyptian medicine: papyri, inscriptions, and mummified remains. These tell us that the Egyptians had words for the skull, brain, vertebrae, spinal fluid and meninges, though they do not say if they assigned any function to them. They described unconsciousness, quadriparesis, hemiparesis and dementia. We can recognize neurological injuries, such as traumatic hemiparesis and cervical dislocation with paraplegia, in the well known Edwin Smith surgical papyrus. Similarly recognizable in the Ebers papyrus is a description of migraine. An inscription from the tomb of the vizier Weshptah, dated c. 2455 BCE, seems to describe stroke, and Herodotus describes epilepsy in Hellenistic Egypt. We have very little understanding of how Egyptian physicians organized these observations, but we may learn something of Egyptian culture by examining them. At the same time, modern physicians feel some connection to Egyptian physicians and can plausibly claim to be filling a similar societal role. PMID:19892106

York, George K; Steinberg, David A

2010-01-01

453

Dental health and disease in ancient Egypt.  

PubMed

In ancient Egypt the exceptionally dry climate together with the unique burial customs has resulted in the survival of large numbers of well-preserved skeletal and mummified remains. Examinations of these remains together with an analysis of the surviving documentary, archaeological and ethnographic evidence has enabled a detailed picture of the dental health of these ancient people to be revealed, perhaps more so than for any other civilisation in antiquity. In this, the first of two articles, the dental pathological conditions that afflicted the ancient Egyptians is considered. The commonest finding is that of tooth wear, which was often so excessive that it resulted in pulpal exposure. Multiple abscesses were frequently seen, but cari