Eastern Sinai Research Articles

A lifetime track of a griffon vulture: The moving story of Rehovot (Y64).

A lifetime track of a griffon vulture: The moving story of Rehovot (Y64).

Paleoecology and Paleogeography of the Cenomanian-Turonian Macrofossils, north Eastern Desert and Sinai, Egypt

Paleoecology and Paleogeography of the Cenomanian-Turonian Macrofossils, north Eastern Desert and Sinai, Egypt

Facies-based model and basin architecture of the Eocene succession in Egypt (Eastern Desert and Sinai): an example for tectonically controlled sedimentation on the southern Tethyan margin

Integration of stratigraphy, spatial evolution, and syn-tectonism paved the way to propose a new depositional model for the Eocene rocks in the Eastern Desert and Sinai. Minia, Darat, Samalut, and Maghagha geological formations have been recognized. Eight sedimentary facies including tidal flat/lagoon complex, restricted inner lagoon, shoals, outer lagoon, back-bank, nummulite bank, fore-bank, and open marine have been identified. They were deposited in the shallow marine photic environment on a gently dipping platform ramp due to north of Egypt. Furthermore, this ramp shows three main faunal associations depending on water depth. The facies zones are arranged into a series of parallel NE-SW elongated subsiding sub-basins, separated by emerged and submerged swells rising from the bottom of the Eocene sea. Physically controlled sedimentary structures indicate a para-autochthonous to bio-concentration of the nummulite bodies. The spatio-temporal variations in the depositional environments and hiatuses in between and within the studied rock units indicate stratigraphic unrest. The Syrian Arc tectonism is the main trigger for such disturbance, which was rejuvenated and enlarged during the Late Cretaceous up to the Neogene in the eastern and southeastern Mediterranean domain.

Cenomanian-Turonian sea-level transgression and OAE2 deposition in the Western Narmada Basin, India

We report the Narmada Seaway began in India during the largest global sea-level transgression and Oceanic Anoxic Event 2 (OAE2) δ13C excursion during the late Cenomanian to early Turonian. The transgression progressed eastward during the Turonian-Coniacian and reached Jhilmili by the end of the Maastrichtian. During this time the Narmada and Godavari Seaways may have joined via the Narmada-Tapti rift and formed a Trans-India Seaway. The history of this major seaway is entombed in a fossil-rich marine transgression of the tectonically active Narmada rift zone. We examined this transgression in the western Narmada Basin, Gujarat, to improve age control based on planktic foraminifera and ostracods and evaluate paleoenvironmental changes based on the Cenomanian-Turonian OAE2 δ13C excursion, δ18O records, and mercury concentrations in sediments as index for volcanic eruptions.Results reveal the onset of the OAE2 δ13C excursion began in the western Narmada Basin during the late Cenomanian coeval with the sea-level transgression and first influx of planktic and benthic foraminifera in the Nimar Sandstone that overlies Archean rocks. The OAE2 δ13C excursion peak was recorded in oyster biostromes followed by fluctuating values of the δ13C plateau in the overlying Limestone with oysters beds, and gradual decrease to background values by the early Turonian. We tested the age of the transgression and δ13C excursion based on planktic foraminifera and ostracod biostratigraphy and successfully compared the results with the Pueblo, Colorado, Global Section and Stratotype Point (GSSP), and the eastern Sinai Wadi El Ghaib section of Egypt.

Petrogenesis of a composite dike system in the Wadi Rimthi area, South Sinai, Egypt

Composite dike systems are a common feature in the basement complex of the Egyptian Eastern Desert and Sinai. These dike systems cut several lithological units, but mostly concentrated in post-orogenic calc-alkaline and alkaline granitoid rocks. New field observations, petrographic studies, and whole rock geochemical data are used to reveal the genesis and evolution of these dikes as well as to examine the genetic relationship between the parent mafic and felsic melts. The investigated composite dike system is characterized by a felsic core and mafic margins. The mafic margins are basalt to andesite in composition, whereas the felsic core is mainly rhyolitic in composition. The mafic dike samples are typically enriched in rare earth elements (REEs) (up to 305 ppm) with fractionated patterns ((La/Lu)N = 7.81–9.25) and mildly fractionated heavy rare earth elements (HREEs) ((Gd/Lu)N = 2.53–2.69). The felsic dike samples have low REE contents (up to 234 ppm) with less fractionated patterns ((La/Lu)N = 4.05–5.59) and weak to unfractionated HREE patterns ((Gd/Lu)N = 1.35–1.53). Major and trace element data of the examined mafic and felsic dikes do not show a clear mutual fractionation history. The marked variations in the K/Rb, Rb/Zr, and La/Sm ratios suggest that mafic and felsic rocks were formed from two individual melts and partly contaminated with crustal materials. According to the incompatible trace element patterns, mafic magma is assumed to be generating from the melting of a garnet-bearing peridotite, modified by the fractionation of amphibole, clinopyroxene, olivine, and zircon. The felsic magma, on the other hand, might have been derived from the melting of garnet-free crustal material dominated by feldspar, apatite, and Fe-Ti oxides, followed by pyroxene and amphibole fractionation crystallization.

Evaluation of the Ground Water Aquifers at the Area between Elarish and Rafah, North Eastern Sinai, Egypt

Evaluation of the Ground Water Aquifers at the Area between Elarish and Rafah, North Eastern Sinai, Egypt

Carbonate platform facies development of the Turonian Wata Formation in central and eastern Sinai, Egypt

The Wata carbonate platform in central and eastern Sinai show a clear pattern of evolutionary development during sedimentation. Three facies are recognized in the carbonate platform. Inner-platform in the south, inter-platform basin in the middle, and outer-platform in the northwest. Such classification was probably performed by the effect of Syrian Arc System that culminated during Turonian in Sinai. Inner-platform includes fining-upward cycles, each begins with packstone, followed by wackestone and capped by lime-mudstone or claystone or molluscan bioclastic wackestone at the base capped by sandy oolitic packstone or dolostone. The dominant faunal associations are molluscs, and echinoids. Inter-platform basin occurs north of inner-platform and extends northwest-southeast direction and comprises fining-upward cycles, each of which begins with bioclastic ostracodal packstone, calcisphere packstone, bioclastic packstone, capped by wackestone and lime-mudstone The faunal association includes, sponge spines, ostracodes, molluscan debris and calcispheres. They were deposited in shoal marine and barrier. The outer-platform occurs at Gebel Giddi and extended northwestwards. The lithofacies are entirely represented by calcisphere wackestone/packstone, with a reduced thickness of 20 m.

Nature of slip transfer between strike-slip faults: The Eastern Sinai (Egypt) shear zone, Dead Sea Transform

The western margin of the Gulf of Elat (Aqaba), a sector of the Dead Sea Transform, is characterized by an N–S striking shear zone with cumulative sinistral (left-lateral) offset of 24 km. The crystalline basement in the study area is unique in its excellent rock and fault exposures forming a >50 km long, shear zone with abundant offset of linear features as well as the contact of the basement with the Infracambrian sub-horizontal peneplain. These features enable accurate measurement of the horizontal and vertical displacements along the major and secondary faults to ±50 m. The small vertical offset of the peneplain surface and a measurement of about 8° net-slip plunge along one of the major faults suggest that along all strike-slip faults, movement was almost pure horizontal slip. Part of this horizontal slip was transferred to neighboring major strike-slip faults by secondary strike-slip faults with negligible loss of displacement. The amount of horizontal slip transferred by normal faults, even in releasing bends, is small due to the high dip angle of these faults. Wide breccia zones and distributed deformation of a small fraction of the horizontal slip is observed when the angle between the strike-slip faults exceeds 30°.

MAMMALS OF THE GENUS CANIS LINNAEUS, 1758 (CANIDAE, CARNIVORA) IN EGYPT

The taxonomic relations of mammals of the genus Canis in Egypt are reassessed on the basis of new, geographically comprehensive material and extensive field survey. Three species that markedly differ in several morphological and ecological characters are recognized. The large canid of the Nile Valley, which has been generally designated Canis aureus lupaster, is sufficiently different from Canis aureus to merit treatment as a separate species under its original name Canis lupaster. Two subspecies of Canis lupaster are recognized in Egypt based on morphological, ecological and biogeographic evidence. The nominal subspecies inhabits the Egyptian Nile Valley north of the First Nile Cataract, while C. lupaster doederleini n. comb. occupies the Nile Valley in Nubia, south of the First Cataract. Canis aureus is represented by two subspecies, Canis aureus syriacus in eastern Sinai and a very small jackal in the hyperarid, northern region of the Egyptian Western Desert. The latter is sufficiently different from known C. aureus subspecies to deserve a separate subspecific status and is herein described as Canis aureus qattarensis ssp. nov. In the Sinai Peninsula, new material shows for the first time the occurrence of the Wolf, Canis lupus. This wolf appears identical with Canis lupus arabs of the Arabian Peninsula. An identification key of Egyptian species of the genus Canis is presented.

Cenomanian-Turonian bivalves from eastern Sinai, Egypt

Cenomanian-Turonian bivalves from eastern Sinai, Egypt

The stygobiont Cirolanidae (Isopoda) of Israel and Sinai

ABSTRACT Three closely similar species of subterranean cirolanid isopods are distributed in Israel and Sinai. Turcolana steinitzi, from Galilee, lives in water in which the chlorinity is <50 mg/1. T. reichi, from the Negev and eastern Sinai, is known from habitats with a water chlorinity of 240–1500 mg/1. T. detecta n. sp. is described; it was found at two spring complexes unveiled by a recent marine regression on the western shore of the Dead Sea, having a water chlorinity of 3000–4000 mg/1. T. detecta n. sp. differs from the other two species especially by its distinctly more slender and elongated uropods, this being even more evident for the endopodites, which have a distinct shape and a remarkably variable armature of the internal margin.

Remnants of Miocene fluvial sediments in the Negev Desert, Israel, and the Jordanian Plateau: Evidence for an extensive subsiding basin in the northwestern margins of the Arabian plate

Relics of a thick, widely spread, fluvial sequence of Early Miocene age are scattered throughout southern Israel, eastern Sinai, the Dead Sea Rift Valley and the western margins of the Jordanian Plateau. These relics are mainly preserved in structural lows, karstic systems, and abandoned stream valleys. The paleogeography of this fluvial system was reconstructed based on the relations between the sequence remnants and the main structural and morphological features of the southeastern Levant region.Three sedimentary associations were identified in the Miocene sequence: a lower part dominated by locally derived clastic sediments; a thicker middle part, composed mostly of far-field allochthonous clastic sediments; and an upper part composed of local as well as allochthonous sediments. The two lower parts are regionally distributed whereas the upper part is syn-tectonic and confined to the Dead Sea basin and the Karkom graben in the central Negev. The composition of the far-field allochthonous sediments points to a provenance of Precambrian crystalline rocks of the Arabo-Nubian massif that were exposed along the uplifted shoulders of the Red Sea Rift as the upper drainage basin of the fluvial system. The diverse mammal remains found in this fluvial sequence suggest a complex of savanna, forests and fluvial habitats similar to those of present East Africa, with monsoon-type rains, which were the dominant water source of the rivers.The thickness of the Miocene sequence in the central Negev is at least 1700m, similar to that of the subsurface sequence encountered in the Dead Sea basin. This similarity suggests that both were parts of an extensive subsiding sedimentary basin that developed between the Neo-Tethys and the uplifted margins of the Red Sea.The relations between the reconstructed pre-depositional landscape of southern Israel during the Early Miocene and the overlying fluvial sequence indicate that the entire area was buried under several hundred meters of fluvial sediments, reflecting a subsidence of the northern margins of the African continent (Arabian plate) before its breakup and the splitting of the Sinai–Israel subplate by the Dead Sea Transform.During the early Middle Miocene the subsidence was inversed as the mountainous backbone of Israel was uplifted. The uplift triggered a large scale denudation that removed the thick Early Miocene fluvial sequence from the Negev and transported the eroded sediments northwestward toward the eastern Mediterranean basin. Additional uplift during the late-Middle Miocene was associated with entrenchment of the Be’er Sheva Valley between the Judea Mountains in the north and the Negev Highlands in the south. This valley was flooded by the sea during the Late Miocene.We suggest that the formation of the Early Miocene subsiding basin at the northern edge of the Arabian sub-plate predated the breakup of the Arabian plate by the DST. The inversion of the subsiding regime, which led to the establishment of the Negev Highlands seems to be intimately related to the detachment of the Sinai–Israel sub-plate from the Arabian plate during the Middle Miocene.

Significance of Detrended Correspondence Analysis (DCA) in palaeoecology and biostratigraphy: A case study from the Upper Cretaceous of Egypt

The Cenomanian–Turonian macrofauna from the Sinai Peninsula, Egypt offers an excellent opportunity to test the applicability of gradient analysis in palaeoecology and biostratigraphy. Detrended Correspondence Analysis (DCA) is a simple multivariate technique for arranging species and samples along environmental gradients. In order to reconstruct palaeoecological patterns and biostratigraphy, 42 samples, 4564 individuals, and 132 species from three sections of eastern Sinai were subjected to DCA. Compared with other multivariate techniques such as cluster analysis, the macrobenthic associations (obtained by DCA) fall fully within or deviate only slightly from associations obtained by cluster analysis. However, DCA makes it possible to arrange these associations from completely random distribution (as tested by cluster analysis) to a temporal gradient. Therefore, it is possible to use this multivariate technique also as a useful tool in biostratigraphy. The first detrended correspondence axis (DC1) reflects a water-depth gradient from onshore to offshore, higher scores being typical of onshore samples from the southernmost section and lower scores being typical of offshore samples from the northern section. Overprinted on the DC1 axis is also a gradient of life and feeding modes, as samples with low scores are dominated by epifaunal species and samples with high scores display a higher proportion of shallow-infaunal taxa. With respect to the second detrended correspondence axis (DC2), substrate composition and water energy are overprinted on this axis as samples with low scores predominantly are coarse-grained carbonates (e.g., reefal rudstone), while samples with high scores primarily are mixed-siliciclastics/carbonates (e.g., marl), which are dominated by low-energy taxa. Because the substrate conditions are closely related to the water energy, the coarse-grained substrates were deposited under high water energy, while the marly facies was deposited under low-energy conditions. Excursions in DC2 scores, reflecting substrate composition and water energy, are used to reconstruct the macrobenthic associations; eight associations and two assemblages were recognized. High stress environments (low DC2 scores) were occupied by less diverse associations such as the Chondrodonta joannae association and the Pchelinsevia coquandiana–Praeradiolites biskraensis association. The latter association is stratigraphically followed by high-diversity associations such as the Ilymatogyra africana–Rhynchostreon suborbiculatum association, which preferred less-stressed environments (high DC2 scores).

The Dababiya Core: A window into Paleocene to early Eocene depositional history in Egypt based on coccolith stratigraphy

The composite Paleocene-lower Eocene Dababiya section recovered in the Dababiya Quarry core and accessible in outcrop in the Dababiya Quarry exhibits an unexpected contrast in thickness between the lower Eocene succession (~Esna Shales) and the Paleocene one (~Dakhla Shales and Tarawan Chalk).We investigate the significance of this contrast by reviewing calcareous nannofossil stratigraphic studies performed on sections throughout Egypt. We show that a regional pattern occurs, and distinguish six areas—Nile Valley, Eastern Desert and western Sinai, Central and eastern Sinai, northern Egypt and Western Desert. Based on patterns related to thicknesses of selected lithobiostratigraphic intervals and distribution of main stratigraphic gaps, we propose that the differences in the stratigraphic architecture between these regions result from differential latest Paleocene and early Eocene subsidence following intense middle to late Paleocene tectonic activity in the Syrian Arc folds as a result of the closure of the Neo-Tethys.

Functional morphology and taphonomy of Cenomanian (Cretaceous) oysters from the eastern Sinai Peninsula, Egypt

The morphological variability of the soft-bottom oysters Ilymatogyra africana (Lamarck, 1801), Costagyra olisiponensis (Sharpe, 1850) and Chondrodonta joannae (Choffat, 1886) from the Cenomanian of eastern Sinai is interpreted in terms of ecophenotypic response to environmental parameters. In I. africana, the influence of coiling and shape of the left valve on the concavity and outline of the right valve can be demonstrated. Type and stability of the substrate also influenced the shell microstructure: In early growth stages, the layers are conformable, becoming unconformable during later growth stages. This unconformity and the pronounced thickening of the dorsal region of the left valve is interpreted to have led to a re-orientation of the organisms in the sediment, thereby protecting them from the danger of becoming buried and of their gills becoming clogged. The three-dimensional spiral growth and high vertical increment of forma typica of I. africana also protected the organisms from becoming buried. The high degree of disarticulation and the concentration of Ilymatogyra shells suggest reworking due to winnowing and bioturbation. In C. olisiponensis, juveniles were cemented to secondary hard substrates, whereas adults were adapted to a free reclining mode of life. Taphonomic analysis of C. olisiponensis shells suggests a lack of reworking and low rates of sedimentation. There exists a relationship between the size of the attachment area and the shell outline and convexity of C. olisiponensis, with a small attachment area occurring in individuals with a wide postero-ventral part and less convex valves and a large attachment area occurring in more elongated shells with strongly convex valves. Chondrodonta shell concentrations occur in various preservational states, which reflect the gradual mixing and mechanical destruction of a former community. Storm-induced waves and currents as well as reduced sediment input were responsible for their formations.

Microbial control on the mineralogy of Arief El Naqa phosphates, Egypt

SEM examination of the pelletal phosphates from the Upper Cretaceous of Arief El Naqa in eastern Sinai reveals the presence of bacterial relics and globular clusters of phosphate, iron oxyhydroxides and halite. All have been identified only within cavities and in the phosphatic cement around phosphate particles. These microbial structures were, therefore, produced by the aid of microorganisms in association with infiltrating meteoric water from the nearby vegetation cover. They were able to accelerate the dissolution of pyrite and the leaching of phosphate particles to use phosphorus as a desired nutrient. Phosphate globular clusters and goethite framboids were formed as the result of crystal growth of the biologically precipitated precursor phases. Bacteria were simply available nucleation sites for binding of these nanoparticles. Halite clusters were also identified in a similar setting and show a co-genetic relationship with other types of microstructures. Therefore, the role of microorganisms in the formation of halite microstructures is suggested, but its inorganic origin cannot be totally excluded.

Permian–Triassic palaeogeography of the external Hellenides

In the External Hellenides two crustal types are developed: (1) a Variscan basement overlain by the Tyros Unit and (2) a presumably Panafrican basement overlain by the Phyllite–Quartzite Group (Late Carboniferous–Early Triassic) and the Plattenkalk Group (Permian–Oligocene). If we accept this assumption, the Plattenkalk and the Phyllite–Quartzite Groups fit well into the Permian–Triassic palaeogeography of the northeastern margin of Afro-Arabia. During the Permian–Triassic there is evidence for a siliciclastic fluvio-marine system in the western Sinai and Nile area, whereas the Early Triassic shelf of eastern Sinai and Israel is dominated by a carbonate platform. The western facies association of the Plattenkalk and the Phyllite–Quartzite Groups represents the northward extension of a fluvio-marine system. The siliciclastics of the Plattenkalk Group formed part of a marine delta, those of the Phyllite–Quartzite Group indicate a turbidite fan system. The units of Middle and Eastern Crete represent the seaward continuation of the carbonate platform (Plattenkalk Group) and a deep sea realm free of turbidite influx (Phyllite–Quartzite Group).During the Permian–Triassic the different crustal segments were brought together due to dextral strike slip movements of Gondwana against the southern margin of the European Plate as indicated by a uniform shallow marine facies of the Carnian/Norian.

On status and conservation of marine turtles along the Egyptian Mediterranean Sea coast: results of the Darwin Initiative Sea Turtle Conservation Project 1998–2000

Surveys showed that a small population (max. 37 nests per year) of Loggerhead Turtles (Caretta caretta), and the occasional Green Turtle (Chelonia mydas), nest along this coastline. Prime nesting areas are concentrated in the eastern region of the Northern Sinai coast close to the border with the Gaza Strip. Turtle nesting activity in the western region from Alexandria to the border with Libya is negligible, and no evidence of nesting was found in the Nile Delta region. The small population of nesting turtles that does exist in the eastern Sinai region is under severe pressure from human activity. Throughout the three year study evidence was found of capture and slaughter of adult turtles at sea; disturbance of nests and eggs on the beaches; reduction in hatchling survival due to heavily polluted nesting beaches; and the loss of nesting sites due to widespread coastal development for tourism. Many hundreds of kilometres of seemingly suitable nesting beaches exist along the Mediterranean coast of Egypt. The number of sea turtles currently nesting in the area has probably been reduced to a fraction of its historic value due to human induced pressures. If the current population is to survive an immediate conservation effort is required; protection of the few remaining nesting beaches and education of the local population about the current plight of sea turtles is essential.

Late Maastrichtian litho- and ecocycles from hemipelagic deposits of eastern Sinai, Egypt

A biostratigraphical and palaeoecological survey employing calcareous nannofossils and planktonic and benthonic foraminifera has been carried out in four sections of hemipelagic marls and chalks of the Late Maastrichtian Abathomphalus mayaroensis Zone of eastern Sinai, in order to evaluate the mechanisms controlling the composition of the well preserved microfauna and nannoflora. The Abathomphalus mayaroensis Zone in eastern Sinai can be easily identified by the wide occurrence of the index fossil A. mayaroensis and can be further subdivided by the first occurrences of Plummerita reicheli (ex. P. hantkeninoides) and Micula prinsii. Microfossil abundances and lithologies are characterised by pronounced repetitive distribution patterns. These include low and high frequency fluctuations of the planktonic/benthonic (P/B) foraminiferal ratio, repetitive changes in the abundance of calcareous nannofossils and benthonic foraminifera, as well as the development of chalk-marl couplets and thinning upward chalk packets. both microfossil distribution patterns and the occurrence of rhythmites are attributed to changes in primary palaeoproductivity. Semiquantitative investigations of calcareous nannofossils and a few selected benthonic foraminifera yield evidence of the presence of high (HP) and low (LP) productivity assemblages. The interpreted HP assemblage is dominated by Glaukolithus diplogrammus, Manvitella pemmatoidea, Microrhabdulus decoratus and Micula murus and the benthonic foraminifera Neoflabellina jarvisi; the LP assemblage is characterised by Lithraphidites quadratus and Bolivinoides draco. However, further quantitative studies are necessary to reconstruct the exact composition of these assemblages and to explain deviatory developments. The chalk-marl couplets, thinning-upward chalk packets and the high frequency P/B patterns are interpreted to reflect productivity changes related to orbital forcing. These hemipelagites were deposited during the latest phase of the southern Tethyan upwelling system, which was active from the Santonian to the Late Maastrichtian with a peak in the Campanian. Termination of upwelling just before the K/T boundary also provides a good explanation for the change towards a palaeobathymetric control on foraminiferal distribution, as observed for the Palaeocene of central east Sinai.

Origin and geochemistry of Egyptian granitoid rocks in Nuweiba area, eastern Sinai

Geological, petrological and geochemical studies indicate two distinct types of granitoid rocks: an older quartz diorite to granodiorite assemblage and younger granitoids, the latter occurring in two phases. The older granitoids have a calc-alkaline character, with high MgO, (FeO) t, TiO 2 and P 2O 5 and low SiO 2, K 2O and Rb. Their major and trace elements compositions, together with a low 87Sr/ 86Sr (0.7029 ± 0.0008) denote I-type affinites. The second and third phase granitoids range from calc-alkaline to alkaline respectively. The second phase granitoids have a peraluminous chemistry and high Sr, Ba, CaO, MgO, Al 2O 3 and Ti 2O, and low SiO 2, K 2O, Zr, Nb and Rb relative to the third phase granitoids. The corundum normative nature and field observations suggest that it was formed by partial melting of the lower crust (S-type). The third phase granitoids are characterized by high SiO 2, Rb, Y, Zr and low MgO, CaO, Sr and Ba values than younger granitoid phase II. They show A-type granitoids which are generated from below or within existing continental crust.