Western Desert Of Egypt Research Articles

A new record and a new ichnospecies of Arachnostega from the Middle Miocene of Egypt

The ichnogenus Arachnostega Bertling, 1992 is recorded for the first time from a bioeroded, coral-rich, Middle Miocene limestone bed in the middle Siwa Escarpment Member (Marmarica Formation) at Siwa Oasis, northern Western Desert of Egypt. These burrowing traces are preserved on the surface of a few internal moulds of bivalves and gastropods. Until now, the ichnogenus Arachnostega included a single ichnospecies, A. gastrochaenae Bertling, 1992. In the material studied herein, two ichnospecies are identified, described, illustrated and compared with other, similar traces. One of these is a new ichnospecies of Arachnostega; this is here named A. siwaensis ichnosp. nov. It is distinguished from A. gastrochaenae in the possession of tunnels that usually branch in a V-pattern; intervals of ramification are longest in the main branch and decrease in second- and third-order branches. Arachnostega traces were produced in a warm, low-energy, shallow-marine (<10 m water depth) environment. Polychaetes are the most likely producers of marine Arachnostega, which are commonly occurred in the same studied bed. This new occurrence is significant in extending the known stratigraphical and geographical ranges of Arachnostega into the Middle Miocene of Egypt.

Structural and facies modeling of the Lower Cretaceous Alam El Bueib reservoirs in the Shushan Basin, Western Desert, Egypt

The Qasr oil and gas field is located in the eastern part of the Shushan Basin in the northern Western Desert of Egypt. Sandstones of the Lower Cretaceous Alam El Bueib Formation are the main oil-bearing reservoirs in the field, and these reservoirs cannot be seismically detected. Consequently, modeling is important to predict the extension of the reservoirs. The present study adopts two types of modeling: structural and facies. Structural modeling is the incorporation of interpreted faults, horizons, and zones into a three-dimensional (3D) grid, while facies modeling distributes lithologic facies within the previously constructed 3D structural grid. All available geological information is utilized in facies modeling, including lithological interpretations from well logs, and sedimentary core and ditch cutting descriptions from mud logs. The structural analysis of the Alam El Bueib Formation in the Qasr Field showed several E-W to WNW-ESE fault systems. The geologic structure, combined with stratigraphy and facies architecture, establishes the framework for traps in this field. Lithology interpretation using electric well logs and mud logs showed four main facies: (1) channel sand, (2) flood plain siltstone, (3) lagoonal shale and mud, and (4) marine carbonates. Facies modeling of the six major units that comprise the Alam El Bueib Formation show variable sand channels deposited in fluvial to mixed deltaic and tidal environments. These channels are oriented N-S to NE-SW and form 20 to 100-ft-thick sandstone reservoirs.

New Approach for Unconventional Reservoirs Rock Typing Characterization: Egyptian Unconventional Gas Reservoirs

The main objective of this research is to enhance unconventional reservoir characterization by developing and/or establishing new correlations through using a real case study of unconventional shale gas reservoir called Upper Safa formation that located in the western desert of Egypt. In addition to describing its geochemical and petro physical reservoir rock and fluid properties more consistently through a full integration among unconventional rock parameters as permeability, porosity, tortuosity, surface roughness, adsorption, type of kerosene, level of maturity, total organic carbon content, and etc. The results showed that Upper Safa formation is a shale gas unconventional resource play that consists mainly of Kaolinite clay and other mixed clay types. Geochemical pyrolysis analysis is used to confirm the presents of Kerogen type III as a shale gas potential reservoir. Interpretation analysis has been used also to confirm the presence of hydrocarbon potential in shale reservoirs depend on the readings that indicating most of shale play. Hence, after applying the surface roughness factor to Total gas in place equation through multiplying the (1-0.4) factor to volume of adsorbed gas in place to get new more accurate value for total gas in place TGIP’ equals 9.12 BCF. Moreover, brittleness ratio average value equals to 50% brittleness. However, TOC results which are obtained within the ranges of very good petroleum potential according to Rock Eval pyrolysis from 2% to 4% TOC. Hence, the results obtained from using of Dykstra Parson permeability variation, Upper Safa formation is highly heterogeneous formation which is very close to 100% heterogeneous formation, as any unconventional shale reservoirs due to the huge variation in the permeability ranges from milli-Darcy ranges to nano-Darcy ranges. Thus, several conventional and unconventional rock typing methods have been applied to overcome this zonation problem, besides establishing a new approach for unconventional reservoirs rock typing.

Origin and geotectonic evolution of Mir Tertiary basaltic andesite dykes, Western Desert, Egypt: Constraints from mineral and bulk‐rock chemistry

Compared with widespread Egyptian Tertiary basaltic rocks, Mir Tertiary basaltic dykes from the Western Desert of Egypt show distinct mineralogical and geochemical characteristics that provide insights into the nature of their mantle source and geotectonic evolution as well as melting and crystallization conditions. Their mineralogical features (i.e., presence of orthopyroxene and lack of olivine) distinguish them from the other Egyptian Tertiary basalts. They have basaltic andesite compositions (SiO2 = 53.55–55 wt.%, Na2O + K2O = 4.64–4.8 wt.%, MgO = 2.66–3.02 wt.%) with tholeiitic character. Temperature of crystallization ranges from 1,112°C to 1,140°C for plagioclase; from 1,085°C to 1,123°C for clinopyroxene; and from 1,034°C to 1,090°C for orthopyroxene. These results are in harmony with petrographic observations which suggest early crystallization of plagioclase, followed by simultaneous crystallization of plagioclase and clinopyroxene, and soon thereafter by orthopyroxene crystallization. Titanomagnetite–ilmenite intergrowths indicate oxygen fugacity (ƒO2) of −12.09 and −9.4 log units, suggesting crystallization at relatively oxidized conditions. Their temperature ranges from 959°C to 1,125°C, suggesting that the titanomagnetite joins the crystallized phases at early stages and continued until later stages. Mir basaltic andesite (MBA) has low Ni (15–27.9 ppm), Cr (19.8–48.5 ppm), and Sc (20–25 ppm) concentrations together with high FeOt/MgO ratios (3.18–3.58) relative to primitive basalts, arguing for their evolved nature. They have sub‐chondritic Nb/Ta ratios (15.5–17) similar to ocean–island basalts and higher than those of continental crust, ruling out a significant effect of crustal contamination. The high La/Nb (&gt;1.4) with the negative Nb, Ta, and Ti anomalies on the primitive mantle‐normalized patterns most likely indicates that their primary magma was derived from partial melting of a mantle source previously metasomatized by influx of subduction‐related slab fluids/melts. Moreover, the super‐chondritic Zr/Hf ratios (39.55–55.21) and the negative K and Ti anomalies point to carbonate metasomatism of their mantle source. This inference is further supported by their high (K2O + Na2O)/TiO2 ratios (&gt;1) which are comparable with experimentally produced carbonated peridotite melts. The high Zr/Y (average 9.75) and La/Yb ratios (8.6–10) of the MBA suggest that they were generated via low degrees of partial melting. Indeed, modelling calculations indicate generation by lower melting degrees (&lt;10%) of a garnet‐bearing lherzolite mantle source. The melting region was at the garnet stability field suggesting a deeper origin (exceeds ~85 km) for MBA. Field and geochemical characteristics of the Egyptian Tertiary volcanism proved that it is spatially and temporally related to extension that has occurred during Red Sea rifting. Extension most likely due to the NE–SW tensional stresses which reactivated the old fractures and triggered mafic magma generation through passive upwelling of the asthenospheric mantle.

Fossil burrow assemblage, not mangrove roots: reinterpretation of the main whale-bearing layer in the late Eocene of Wadi Al-Hitan, Egypt

The UNESCO World Heritage Site of Wadi Al-Hitan near Fayum in the Western Desert of Egypt is well-known for its remarkable abundance and diversity of late Eocene marine fossils, especially well-preserved cetaceans and sirenians. However, the taphonomy of the early Priabonian whales and sea cows is still not fully understood. These marine mammals often occur on specific horizons in the Birket Qarun Formation, for example, on a distinctive firmground called the Camp White Layer (CWL). Vertical, rod-like structures in the CWL were previously interpreted as “mangrove pneumatophores,” which have influenced hypotheses about the habitat of early whales. Here, we reexamine the rod-like structures of the CWL and show that they do not represent mangrove rooting structures based on an analysis of their morphology and an extensive comparison with rooting structures of living mangroves. Instead, the morphology of the rod-like structures indicates that they are trace fossils representing five size classes of marine invertebrate burrows, including burrows of weakly umbonate clams and Ophiomorphidae. The complex overprinting of all burrows toward the top of the CWL indicates stratigraphic condensation caused by low overall rates of sedimentation on a marine flooding surface in the transgressive systems tract. The large number of whale carcasses, abundant invertebrate skeletal remains, logs, marine invertebrate-encrusted celestine crystals, and an extensive, diverse burrow network reflect a combination of environmental and temporal condensation. A peculiar feature of the CWL, celestine crystal aggregates and gastropod celestine pseudomorphs, indicate an evaporative phase that is difficult to reconcile with the current sequence stratigraphic framework.

Characterization of some Egyptian Sheep Populations Using Microsatellite and Protein Markers

Three Egyptian sheep populations, collected from three geographically isolated regions namely Siwa, El-Dakhla and El-Farafra oases of the Egyptian western desert, were investigated using six polymorphic microsatellite markers and electrophoretic protein by SDS-PAGE. Six polymorphic microsatellite markers and electrophoretic protein were used to reveal that the genetic diversity, conduct genetic structure and assignment of microsatellite. The results indicated that; one hundred and five alleles were detected; 34 are common alleles and 71 specific alleles across six loci (67.62%). Thirteen specific alleles for Siwa sheep population ranged from 1 to 5. Also, for Dakhla sheep population 21 alleles ranged from 1 to 8. While 37 ones were obtained in the case of Farafra sheep population ranging from 1 to 14. When the heterozygotsity is high we will have the highest effective number of alleles (ENA) and the expected heterozygosity (gene diversity). The highest ENA was 10.29 for BM1314 when HE was 0.94, while the lowest ENA was 2.22 for BM8125 when HE was 0.58 with El-Dakhla sheep population. The protein profile for 33 sheep population samples collected from three different regions, Siwa had 20 protein bands that MW ranged from 17 to 269KDa. At the same concentration of protein and molecular weight, the band's volume or intensity values changed from sample to other. The homogeneity of individual Siwa samples was 30%. El-Dakhla population had 23 protein bands that ranged from17 to 283KDa. The heterogeneity’s El -Dakhla population was 74%. While, El-farfra populations varied in electrophoretic protein pattern, it had 21 bands that ranged from 17 to 252 KDa. The homogeneity percentage was 24%. Finally, protein profile can be used as a marker depending on the presence or absence bands, band intensity, molecular weight and relative front values.

Domestication of cattle: Two or three events?

Cattle have been invaluable for the transition of human society from nomadic hunter‐gatherers to sedentary farming communities throughout much of Europe, Asia and Africa since the earliest domestication of cattle more than 10,000 years ago. Although current understanding of relationships among ancestral populations remains limited, domestication of cattle is thought to have occurred on two or three occasions, giving rise to the taurine (Bos taurus) and indicine (Bos indicus) species that share the aurochs (Bos primigenius) as common ancestor ~250,000 years ago. Indicine and taurine cattle were domesticated in the Indus Valley and Fertile Crescent, respectively; however, an additional domestication event for taurine in the Western Desert of Egypt has also been proposed. We analysed medium density Illumina Bovine SNP array (~54,000 loci) data across 3,196 individuals, representing 180 taurine and indicine populations to investigate population structure within and between populations, and domestication and demographic dynamics using approximate Bayesian computation (ABC). Comparative analyses between scenarios modelling two and three domestication events consistently favour a model with only two episodes and suggest that the additional genetic variation component usually detected in African taurine cattle may be explained by hybridization with local aurochs in Africa after the domestication of taurine cattle in the Fertile Crescent. African indicine cattle exhibit high levels of shared genetic variation with Asian indicine cattle due to their recent divergence and with African taurine cattle through relatively recent gene flow. Scenarios with unidirectional or bidirectional migratory events between European taurine and Asian indicine cattle are also plausible, although further studies are needed to disentangle the complex human‐mediated dispersion patterns of domestic cattle. This study therefore helps to clarify the effect of past demographic history on the genetic variation of modern cattle, providing a basis for further analyses exploring alternative migratory routes for early domestic populations.

Gebel Ramlah\u2014a Unique Newborns\u2019 Cemetery of the Neolithic Sahara

Post-Pleistocene climatic improvement in the Northern Hemisphere after ca. 9550 BC allowed human populations to recolonize large parts of North Africa in what is today the Sahara Desert. In the Egyptian Western Desert, the beginnings of human occupation date as early as ca. 9300 BC. Occupation continued until the middle of the third millennium BC when final desertification of the area no longer afforded human occupation. The settlement of the Neolithic cattle and sheep/goat herders developed along with the rhythm of alternating wet and dry climatic oscillations. One of the areas occupied intensively during the early and middle Holocene was Gebel Ramlah. Pastoral populations established their settlements around the shores of a paleo-lake adjacent to a rocky massif, to exploit the local savannah environment. During most of the Neolithic, they buried their dead dispersed outside of their settlements. Only during the Final Neolithic (after ca. 4600 BC) did they place them exclusively in cemeteries. Of six Final Neolithic cemeteries investigated at Gebel Ramlah to date, one is entirely unprecedented, not only in North Africa but also globally at such an early date. For just under 200 years (ca. 4500–4300 BC), it served exclusively for the inhumation of infants who died around (perinate) or shortly after the time of birth (neonate). Thirty-two burial pits contained skeletal remains of 39 individuals, not only infants but also at least two adult females accompanied by perinates/neonates. Older children (> 3 years) were interred at a nearby cemetery that primarily comprised adults.

Utilizing the geological data and remote sensing applications for investigation of groundwater occurrences, West El Minia, Western Desert of Egypt

West EL Minia area is considered one of promising areas for future development plans in Egypt. The current research provides an integrated remote sensing data, microfacies analysis, field studies and geochemical approach to investigate the groundwater resources in West El Minia area. Three aquifers were investigated; Oligocene sandstone, Middle Eocene limestone and Nubian sandstone aquifer. New data about two aquifers (Nubian sandstone and Oligocene) are presented in the current study extracted from well logging interpretation and wells rock samples. The groundwater of the Oligocene sandstone and Middle Eocene limestone aquifers are recorded under unconfined conditions, while the Nubian sandstone is recorded as confined aquifer. The total thicknesses of the three aquifers were identified through interpretation of the well logging data (180 m for Oligocene aquifer, 445 m for the Middle Eocene aquifer, and 145 m for Nubian sandstone aquifer). The present study discusses the groundwater levels, the geological controls and groundwater chemistry of the recorded aquifers. The low salinity values (560–916 mg/l) and water table map as well as the obtained stable isotopes data reveal that the Middle Eocene aquifer is recharged from the Nile River where it has isotopic signature of the modern Nile water with slightly contribution of paleo-water of the Nubian sandstone. The area is affected by sets of faults associated with fractures and joints and facilitates the groundwater recharge. Based on multi GIS data layers, remote sensing data, geologic investigation as well as geophysical data, a future groundwater strategy were presented.

Building up and Characterization of Calcined Marl-Based Geopolymeric Cement

The present study mainly investigates the synthesis of calcined marl-based geopolymeric cement under different synthesis conditions including NaOH concentration, sodium silicate (SS)/sodium hydroxide (SH) mass ratios, solid (S)/liquid (L) mass ratios, calcination temperatures, curing temperatures, curing times, and aging intervals. The studied head sample was obtained from the Abu-Tartur phosphate mine in the Western Desert of Egypt and subjected to chemical and mineralogical characterizations using X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transform–infrared spectroscopy (FT–IR). Regarding calcination, this was conducted at 550, 650, 750, and 850 °C for one hour and resulted in thermal decomposition of calcite and saponite and the formation of new mineral phases including anthophyllite, wollastonite, and silica. On the other hand, the geopolymerization process was initiated by mixing the calcined marl sample with the alkali activation solution at different mixing ratios and varying curing conditions. The compressive strength measurements indicate that 750 °C, 12 M NaOH, 0.6 SS/SH mass ratio, 2 S/L mass ratio, 80 °C curing temperature, 12 h curing time, and 28 days aging time are considered all to be the optimum synthesis conditions of the Abu-Tartur calcined marl-based geopolymer.

Sedimentary facies analysis of the Upper Bahariya sandstone reservoir in East Bahariya C area, North Western Desert, Egypt

The present work aims to deduce the depositional processes of the Lower Cenomanian Bahariya Formation, that is one of the main hydrocarbon siliciclastic reservoirs in the Northern Western Desert of Egypt. This has been achieved through the analyses of the core photographs, micro-resistivity image logs, mud logs and conventional wireline logs. The Bahariya Formation comprises a complex of depositional lithofacies such as interbedded siltstone, shale, sandstones and pebbly sandstones. The current work highlights the effectiveness of the integrative approach. A variety of datasets including core photographs, micro-resistivity image logs, mud logs and conventional wireline logs are integrated to define the conceptual depositional model in the study area.Different recorded sedimentary features point to various depositional processes. Hummocky cross stratification (HCS) is the common sedimentary structure indicating the storm action. Wave ripples are recorded providing evidence for fair-weather action on shoreface. Rhythmic heterolithics, tidalites indicate the tidal processes. The upper part of the Bahariya Formation has been influenced by wave and storm processes more than the lower parts. The core and image facies are designated, being dominated by Sandstone (S), Siltstone (Z), Mudstone (M), Heterolithic (H) and Limestone (L.s). The studied core and image facies with wireline logs facies are grouped into five major facies associations (FA). They are Tidal Channel and Tidal Creeks, Tidal Flat, Storm, Shoreface, Offshore Transition to Offshore Facies Associations. The integrative approach indicates that the Upper Bahariya Member has been deposited in a storm influenced tidal coastal realm.

Unlocking Egypt’s Unconventional-Resource Potential

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 188587, “Unlocking Egypt’s Unconventional Potential,” by Amr Zaher, Etienne Loubens, Mohamed Zayed, SPE, Nicholas Gill, SPE, Oneil Sadhu, SPE, and Layla El Hares, SPE, Shell, prepared for the 2017 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 13–16 November. The paper has not been peer reviewed. The Apollonia tight-gas chalk play is located in the Abu Gharadig Basin in the Western Desert of Egypt. This has long been ignored as a gas play in the overburden, while the Jurassic and Cretaceous oil fields deeper in the basin have been explored and developed. However, several structures in the Apollonia are known to contain potentially significant hydrocarbon volumes, although a potential Apollonia full-field development is challenging because of regulated gas prices in the Western Desert and low-productivity formations. This paper discusses the process of developing the first unconventional-gas opportunity in Egypt. Introduction Vertical appraisal wells show that low production rates and low estimated ultimate recoveries (EURs) present a challenge for cost-effective development of tight gas in Apollonia. With the play’s decreasing levels of permeability, long-reach horizontal wells are needed with induced stimulation. The optimized technique of deploying multistage hydraulic-fracture stimulation efficiently has been documented and applied successfully in North America and has potential for success in Apollonia. Shell and Apache created a joint-development proposal to unlock the significant stranded gas in Apollonia. The proposal consisted of a staged development, starting with a three-horizontal-well pilot followed by an optional full-field development. Geology Apollonia is a homogeneous reservoir; however, it is very tight, and induced stimulation by hydraulic fracturing is required to produce a commercial and sustainable production rate. Smectite and illite contribute to reservoir quality and can be predicated by conventional logs. Fracture densities in Apollonia are low. The fractures are either closed or only partially open, and their contribution to production is perceived to be low. In addition to these factors, development may require drilling many wells (low spacing) with induced stimulation in order to deliver cost-effective production rates. This requires lower well costs than currently exist. While production from the three existing vertical wells continues, EURs from these wells are suboptimal. Apollonia comprises tight, microporous chalky carbonates that are proved to contain movable hydrocarbons. The formation is subdivided into four members, Apollonia A (top layer) through D (bottom layer). Apollonia A and C are composed of thick massive limestones (chalk) with minor marly and shaley intervals, while Apollonia B and D are dominated by shale. Most of the porous intervals occur within Apollonia A and C. Regional correlations have shown that most of the thickness variations are confined to Apollonia C and, to a lesser extent, D. However, recent seismic interpretation has shown that there are also thickness variations in Apollonia A and B associated with Eocene inversion. The individual porous zones within Apollonia A and, to a lesser extent, C are laterally correlatable over large distances.

Petrophysical reservoir-rock properties and source-rock characterization of Abu Roash Formation in Wadi El-Rayan oil field, Western Desert, Egypt

Wadi El-Rayan oil field is located in one of the most prolific basins in the northern part of the Western Desert of Egypt. This field produces oil mainly from Abu-Roash Formation which is differentiated into various members of which Abu Roash G and F Members are the most important. This study aims to investigate the different reservoir properties of the Abu Roash G Member (ARG) and evaluate the potential contribution of Abu Roash F Member (ARF) as a source. The well logging data of 10 wells are utilized mainly for enhancing the petrophysical and the source rock analyses. The standard logging analyses usually used for characterizing the hydrocarbon reservoirs are applied. A mixed clastic and carbonate approach is applied for detecting the lithology. Fluid saturations (water and hydrocarbon) are estimated using clean and shaley modules. Estimation of total organic carbon (TOC) is based on ΔlogR method as matched with geochemical and Rock Eval pyrolysis measurements. The deduced petrophysical parameters are represented vertically as reservoir analogs and distributed laterally in a number of property variation maps. The study revealed that Abu Roash G Member is divided into zones, of which the reservoir pay zone (RP zone) attains the best reservoir properties. Ranges of 16.5–52.5 and 3.0–19.5 m and 8–26, 19–26, and 45–73% are given for gross and net pay thicknesses, shale volume, effective porosity, and hydrocarbon saturation, respectively. The lateral distribution maps of the reservoir and source rock parameters showed that net reservoir thickness, hydrocarbon saturation, and TOC content increase toward the central of the study area. The ΔlogR overlays revealed that ARF Member is a good source rock which is classified into two overlying zones. The upper zone (ARF-SR1) has fair to good source characteristics, while the lower zone (AFR-SR2) is the main source rock with TOC content range of 2.13 to 4.12%. The Rock Eval and geochemical measurements strongly indicate oil-prone facies with hydrogen indices of 509–705 and S2 yields of 9.42–23.26 mg HC/g. In conclusion, the ARG Member showed good hydrocarbon potentiality and reservoir properties. The organic enrichment of the overlying ARF-SR2 zone offered the main source potentiality. Based on the petrophysical data logs and distribution maps, it is recommended to consider central part of the field for any further hydrocarbon exploration/production activity.

IMPACT OF COVERING IRRIGATION CANALS ON EVAPORATION RATES IN ARID AREAS

Water is the essence of life; thus preserving enough quantities and good quality of water will elevate the standards of living and health of communities. Egyptian government approved Toshka New Valley project to help deal with the rapidly growing population of the country. The project entails building a series of canals; the main is Sheikh Zayed canal - to irrigate portions of the Western Desert of Egypt. It is expected that the recovered land will become home to three million residents by 2020 and cultivate about 550000 feddans. Toshka is a very arid area with high air temperatures; thus very high evaporation rate; about 3 billion m3/year. Researches showed that in the near future Egypt will face scarcity of water. So saving water from Sheikh Zayed canal by reducing evaporation will provide additional source of water to the area. This research aim is to estimate evaporation rate from the canal and its main branches. Variable configurations and spacing of covering canals were chosen to reduce evaporation and at same time allow for re-aeration and other water quality parameters to meet their standards. It was found that full coverage calculated evaporation amount is about 9 million m3/year which could drip irrigate 35000 feddans of wheat per year which is about 7% of the total area of the land intended to be cultivated in Toshka project.

Geochemical assessment of Paleocene limestones of Sinn El-Kaddab Plateau, South Western Desert of Egypt, for industrial uses

The present work assesses the potential industrial uses of Paleocene limestone deposits, Garra Formation in Sinn El-Kaddab Plateau, South Western Desert of Egypt, based on their mineralogy and geochemical characteristics. Eighty-six limestone samples collected from ten stratigraphic columnar sections were analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Petrographically, Garra limestone deposits consist dominantly of benthic foraminiferal wackestone and packstone microfacies. The XRD data revealed dominance of low-Mg calcite as essential carbonate mineral in the studied limestone. The bulk rock XRF results revealed CaO (29.28–55.75%) with an average of 52.74%. The CaO exhibits a strong negative correlation with MgO, SiO2, TiO2, Al2O3, and moderate negative correlation with Fe2O3 which indicates that the contribution of these elements is mainly due to detrital input. On the other hand, Al2O3 and Na2O contents exhibit significant negative correlation with loss of ignition (LOI) wt% indicating their incorporation within terrigenous matrix. The average Sr content attains 1297 ppm indicating deposition in temperate marine environment. The average molar CaCO3% values of bulk samples have been computed for individual columnar sections to determine the purity status of Garra limestone deposits. They range from impure (CaCO3% = 79.92%) to high-pure (CaCO3% = 97.76%) limestone. Therefore, Garra limestone deposits have extremely valuable uses in a wide spectrum of industrial applications including Portland cement, steel, ceramics, whiting, chemical uses, paper, and feed stuff.

Provenance studies of Kalabsha kaolin deposits, Egypt: a petrographical and geochemical approach

The present study focuses on the kaolin deposit in Kalabsha area south Western Desert of Egypt in an attempt to determine its possible source, tectonic setting, and weathering history by means of integrated petrographical and geochemical approaches. The petrographical study was worked by microscopic investigation and supported by X-ray diffraction analysis. X-ray fluorescence and inductively coupled plasma-mass spectrophotometry methods were used for the determination of the bulk elemental composition. Mineralogical analysis revealed that kaolinite is the main clay mineral component indicating a severe chemical weathering of Al-rich source rocks and complete leaching under warm, semiarid climatic conditions. The nonclay minerals are represented by quartz, iron oxides and hydroxides, Ti-bearing minerals, and zircon. Geochemical data show a prevalence of SiO2 and Al2O3 and enrichment of Hf, Nb, Ta, Th, U, and Zr that support the kaolinitic nature of the deposits and their derivation from a felsic granitic terrain. The high values of the chemical index of alteration and the lower values of the index of compositional variability also suggest an intensive weathered source area and the geochemical maturity of the sediments. Other relevant geochemical discriminant functions and plots reveal felsic igneous parent rock for the kaolin deposits. Q-mode hierarchical cluster analysis combined with the normalized rare earth element patterns played a crucial role in unraveling the origin of the studied deposits. The results show that the most probable source rock of the Kalabsha kaolin deposits is the intense weathering of relatively proximal Adara Adatalob granites and their similar rock types in the Arabian-Nubian Shield from the south Eastern Desert of Egypt.

The effect of mineralogy of calcined shales on the alkali activation and geopolymerization reactions: A case study from Abu-Tartur plateau, Western Desert, Egypt

Abstract The effect of mineralogy of calcined shales on the alkali activation and geopolymerization reactions was studied. Shales under study included black and Dakhla shales, which were obtained from the Abu-Tartur plateau in the Western Desert of Egypt and characterized using optical microscope, SEM, XRF, XRD, and FTIR. The dehydroxylation of shale samples was performed at 550, 650, 750, and 850 °C for one hour. The mineral transformations on calcination were monitored using SEM, XRD and FTIR. The alkali activation process was then conducted on the calcined samples using a mixture of sodium hydroxide and sodium silicate at 1.2 solid/liquid mass ratio. The resultant pasts were molded in steel cubes (50 × 50 × 50mm in diameter) and cured at 70 °C for 48 h. The compressive strength of cured samples was measured to reveal the extent to which the dehydroxylation achieved. The maximum strength values were reported at 4.19 MPa and 2.49 MPa for the calcined black shale and Dakhla shale, respectively. By comparing with literature, the present strength is considered to be too much low. This indicates a deficiency of the dehydroxylation of clay minerals, a little amount of the active amorphous phases, and the dominance of low reactive crystalline phases through the whole range of calcination process.

Distinguishing rift-related from inversion-related anticlines: Observations from the Abu Gharadig and Gindi Basins, Western Desert, Egypt

Distinguishing the tectonic origin of anticlinal structures is problematic in regions with a complex history of rifting and inversion. We present the results of seismic mapping, in the form of time-depth (isochron) and time-thickness maps to characterize how sedimentary thickness differentials evolved in response to normal faulting and to inversion events on faults within the Abu Gharadig and Gindi Basins in the Western Desert of Egypt. Late Cretaceous rift-related faults in the Abu Gharadig Basin strike NW-SE, W-E and SW-NE. In the eastern part of the basin, a prominent SW-NE trending interbasinal saddle formed in response to preferential subsidence forming half-grabens to its north-west and southeast, during the Mid-Turonian to Santonian interval. Santonian to Palaeogene inversion in the Abu Gharadig Basin developed on its northern basin margin, the absence of SW-NE striking faults in the eastern central basin resulting in any inversion effects being minor. In the central Gindi Basin, Upper Cenomanian to Lower Turonian SW-NE striking rift faults underwent inversion as early as the Mid-Turonian. The orientation of existing rift faults and modification of the local stress fields control the extent to which inversion was taken up in each basin trough time. The Abu Gharadig and Gindi Basins are two of the rift basins developed in West and Central Africa that underwent rifting, inversion and dextral shearing during the Late Cretaceous. We emphasize the value of high-resolution stratigraphic mapping to characterize short-lived and subtle pop-up events that may have gone unnoticed.

Sequence stratigraphic evolution of the syn-rift Early Cretaceous sediments, West Beni Suef Basin, the Western Desert of Egypt with remarks on its hydrocarbon accumulations

The Beni Suef Basin is a petroliferous rift basin straddling the River Nile containing a thick Mesozoic–Paleogene succession. The Kharita Formation is formed in the syn-rift phase of the basin formation and is subdivided into the Lower and Upper Kharita members. These two members are regarded as two third-order depositional sequences (DSQ-1 and DSQ-2). The lowstand systems tract (LST-1) of the DSQ-1 is represented by thick amalgamated sandstone bodies deposited by active braided channels. Mid-Albian tectonic subsidence led to a short-lived marine invasion which produced coastal marine and inner-shelf facies belts during an ensuing transgressive systems tract (TST-1). At the end of the mid-Albian, a phase of tectonic uplift gradually rose the continent creating a fall in relative sea level, resulting in deposition of shallow marine and estuarine facies belts during a highstand systems tract (HST-1). During the Late Albian, a new phase of land-rejuvenation commenced, with a prolonged phase of fluvial depositional. Fluvial deposits consisted of belts of amalgamated, vertically aggraded sandstones interpreted as braided and moderately sinuous channels, in the lower part of the Upper Kharita Member lowstand stage (LST-2). The continuous basin filling, coupled with significant lowering in the surrounding highlands changed the drainage regime into a wide belt of meandering river depositing the transgressive stage (TST-2). The history of the Kharita Formation finalized with a Cenomanian marine transgressive phase. Economically, the TST-1 and HST-1 play a significant role as source rocks for hydrocarbon accumulations, whereas LST-2 act as good reservoir rocks in the Early Cretaceous in the Basin.

A Metrological Study of the Late Roman Fort of Umm al-Dabadib, Kharga Oasis (Egypt)

This article contains a first metrological analysis of the Late Roman Fort of Umm al-Dabadib, built at the beginning of the 4th century AD at the outskirts of the Kharga Oasis, in the Egyptian Western Desert. This site is currently under study by the Italian Archaeological Mission to Umm al-Dabadib; after completing the 3D survey of the building, the team moved to the study of its dimensional patterns. The resulting 3D model was tested for the use of Roman and Egyptian units of measurement, and revealed that the building was planned and built according to the Egyptian Reformed Cubit. The Fort of Umm al-Dabadib, therefore, currently represents the latest attestation of the use of the Egyptian cubit in architecture.