Mahmoud Kora

Lithostratigraphy and facies development of upper cretaceous carbonates in east central Sinai, Egypt

SummaryThe Upper Cretaceous exposures in east central Sinai are represented by carbonate-dominated successions interbedding few sandstone, chert, shale and marl horizons. The recognised rock units are correlated with their counterparts commonly used in the Gulf of Suez region and central Sinai including from base to top: the Raha Formation, Abu Qada Formation, Wata Formation, Matulla Formation and the Sudr Chalk.Twelve limestone microfacies are encountered and are categorised as mudstones (pelmicrite and ostracod micrite), wackestones (pelagic biomicrite and foraminiferal biomicrite), grainstones (foraminiferal biopelsparite and oosparite), boundstones (bindstone and framestone), floatstones (coated-grained biomicrudite, rudist biomicrudite and shelly biomicrudite) and rudstones (shelly biosparudite). The dolostone microfacies include fine-medium crystalline ostracod dolostones and shelly dolostones. These microfacies have been compared with the Standard Microfacies Types and their depositional environments are discussed.The encountered litho- and biofacies suggest that the Cenomanian shallow transgressive sea had covered east central Sinai as far south as the Dahab region. By the advent of the Turonian, open marine subtidal conditions prevailed. This was followed by transitional conditions with shoals and tidal bars in the Late Turonian pointing to a regressive phase more pronounced at the southern localities. The rocks of the Matulla Formation were deposited in an oscillating environment of shallow subtidal to intertidal conditions during Coniacian-Santonian. In the Late Santonian and during most of the Campanian-Maastrichtian, sedimentation was influenced by open marine conditions with low sedimentation rates; local shallow subtidal regressive events occurred.

Lithostratigraphy of the manganese-bearing Um Bogma formation, west-central Sinai, Egypt

Abstract Detailed investigation of the Lower Carboniferous carbonates of the Um Bogma Formation in 49 surface sections and 45 boreholes in west-central Sinai led to the possibility of subdividing this economically important formation into three lithostratigraphic units including from base to top: Ras Samra Member, El Qor Member and Um Shebba Member. These formal names are established here for the first time and are described in detail. Strata-bound manganese-iron ores are recorded from the three members, but economic deposits are confined to the Ras Samra Member only. The lithologic variations of these members and the stratigraphic distribution of the associated MnFe ores are discussed.

Early cretaceous palynomorphs from Gabal Musaba Salama area, Southwestern Sinai, Egypt

Abstract Palynological study of the kaolin-bearing Malha Formation of southwestern Sinai yielded a rich, well preserved palynomorph assemblage advocating a Neocomian age. The palynofloras are recovered only from 14 black shale samples associated with the kaolinitic beds. They consist mainly of spores and pollen grains elucidating nonmarine conditions of deposition. Comparison with other relevant microfloras recovered from stratigraphically equivalent units suggests that the Sinai palynomorphs could be linked with the Laurasian European assemblages.

Facies architecture and depositional development of Middle Miocene carbonate strata at Siwa Oasis, Northwestern Egypt

Based on microfacies analyses and sedimentological data, 17 facies are identified within the Middle Miocene carbonates at Siwa Oasis in the northern Western Desert of Egypt. These facies are attributed to five main facies belts. Within these facies and facies belts, five foraminiferal assemblages are recognized. A depositional model relates the reported facies and biofacies to a down-dip depositional profile of an inner to middle carbonate ramp. The facies of the peritidal to restricted lagoon (facies belt 1) and the less-restricted lagoon (facies belt 2) were deposited in the inner ramp behind the barrier/beach shoal facies belt 3. Basinward, lime mudstone of facies belts 4 and 5 accumulated in a proximal to distal middle ramp, respectively. The depositional evolution involved three stages, which are strongly controlled by tectonics and eustatic sea-level changes. The first stage comprises the transgressive Lower Miocene clastic-dominated fluvial facies of the Moghra Formation. The second stage heralds the deposition of the Langhian inner-ramp carbonate and shale facies of the basal Oasis Member of the Marmarica Formation under a relatively high stand of sea level, constrained clastic influx and climate warming. The final stage is represented by Langhian to Serravallian mid-ramp carbonate-dominated facies of the Siwa Escarpment and El Diffa Plateau members under fluctuating sea level, and a westward restriction in clastic supply and water turbidity.

Carboniferous macrofauna from Sinai, Egypt: biostratigraphy and palaeogeography

Abstract The study of Carboniferous successions in the Um Bogma and Abu Durba areas of west-central Sinai yielded 70 species of brachiopods, corals, bryozoans, molluscs and trace fossils, 10 of which are new to Sinai. The distribution of these fossils suggests the presence of three macrofaunal biostratigraphic units within distinctive lithofacies: a Middle-early Late Visean coral/brachiopod assemblage in the Um Bogma Formation, a Serpukhovian-Bashkirian brachiopod/trace fossil assemblage in the Abu Thora Formation and an Early Moscovian brachiopod/bryozoan assemblage in the Abu Durba Formation. The fossil associations indicate that the Carboniferous sequence of Sinai was deposited in a subtropical epicontinental sea inferred to have covered a greater area in northern Africa. The palaeoecological conditions and the palaeobiogeographic relations of these macrofaunas to the Carboniferous Palaeotethys Realm are discussed.

Sedimentology and reservoir characterization of the Upper Miocene Qawasim Formation, El-Tamad Oil Field onshore Nile Delta, Egypt

The Upper Miocene Qawasim Formation is an important hydrocarbon reservoir in the Nile Delta Province. This paper presents the diagenetic features and the reservoir characteristics of this formation based on conventional core analysis performed on the El-Tamad-2 well. The Qawasim Formation is consisted of low compacted, poorly cemented, massive, and laminated sandstones with gradual upward facies change to tightly cemented bioclastic and dolomitic sandstones. The sandstones are capped by shallow marine bioclastic limestones followed by the open marine Globigerina wackestone and mudstone facies of the Pliocene Kafr El-Sheikh Formation. The channel-fill massive and laminated sandstones are classified as subarkose arenites with well-preserved primary intergranular porosity and good secondary porosity due to the dissolution of feldspars. In addition, they have low clay volume, well-connected pore spaces, and hence very good reservoir quality. On the other hand, the bioclastic and dolomitic sandstones were affected by the diagenetic alterations. Dolomite cement blocked the intergranular pores and reduced the primary porosity, while the dissolution of bioclasts and feldspars increased the secondary porosity. The reservoir quality decreases dramatically with increasing the marine influence from the channel-fill sandstones to dolomitic and bioclastic sandstones, shallow marine bioclastic limestone, and marine mudstone facies. The massive sandstones at the bottom of the upper part of the Qawasim Formation represent the best reservoir quality interval with excellent porosity and permeability values and have proven to be the main target for future exploration activities.

Pleistocene scleractinian corals from Marsa Alam area, Red Sea Coast, Egypt: systematics and biogeography

Coral reef terraces are investigated in five localities around Marsa Alam on the Egyptian Red Sea Coast. The reefal limestones and the alternating terrigenous clastics are assigned to the Pleistocene Samadai Formation. Sixty-one scleractinian coral species belonging to 25 genera and 10 families were identified. Thirteen scleractinian species, for the first time recorded from the Egyptian Red Sea coastal plain, are systematically studied. The stratigraphic distribution of these fossils is illustrated and discussed. Six species are extended to the Miocene and five other species are recorded from the Pliocene and still living in the present Red Sea and the Indo-Pacific. The geographic distributions of the identified coral species are illustrated on maps. These maps show that, all the identified coral species are distributed only throughout the Indo-Pacific realm, increasing from the central part westwards across the Indian Ocean to the Red Sea. There are four species that are restricted to the Red Sea, Arabian region and West Indian Ocean.

New Egyptian sauropod reveals Late Cretaceous dinosaur dispersal between Europe and Africa

Prominent hypotheses advanced over the past two decades have sought to characterize the Late Cretaceous continental vertebrate palaeobiogeography of Gondwanan landmasses, but have proved difficult to test because terrestrial vertebrates from the final ~30 million years of the Mesozoic are extremely rare and fragmentary on continental Africa (including the then-conjoined Arabian Peninsula but excluding the island of Madagascar). Here we describe a new titanosaurian sauropod dinosaur, Mansourasaurus shahinae gen. et sp. nov., from the Upper Cretaceous (Campanian) Quseir Formation of the Dakhla Oasis of the Egyptian Western Desert. Represented by an associated partial skeleton that includes cranial elements, Mansourasaurus is the most completely preserved land-living vertebrate from the post-Cenomanian Cretaceous (~94–66 million years ago) of the African continent. Phylogenetic analyses demonstrate that Mansourasaurus is nested within a clade of penecontemporaneous titanosaurians from southern Europe and eastern Asia, thereby providing the first unambiguous evidence for a post-Cenomanian Cretaceous continental vertebrate clade that inhabited both Africa and Europe. The close relationship of Mansourasaurus to coeval Eurasian titanosaurians indicates that terrestrial vertebrate dispersal occurred between Eurasia and northern Africa after the tectonic separation of the latter from South America ~100 million years ago. These findings counter hypotheses that dinosaur faunas of the African mainland were completely isolated during the post-Cenomanian Cretaceous.A new titanosaurian sauropod, Mansourasaurus, is the most complete terrestrial vertebrate from the post-Cenomanian Cretaceous of the African mainland. Phylogenetic analyses reveal the existence of a titanosaurian clade inhabiting both Africa and Europe at this time and a faunal connection between the two continents.

A New Genus and Species of Marine Catfishes (Siluriformes; Ariidae) From the Upper Eocene Birket Qarun Formation, Wadi El-Hitan, Egypt

Wadi El-Hitan, the UNESCO World Heritage Site, of the Fayum Depression in the northeast part of the Western Desert of Egypt, has produced a remarkable collection of Eocene vertebrates, in particular the fossil whales from which it derives its name. Here we describe a new genus and species of marine catfishes (Siluriformes; Ariidae), Qarmoutus hitanensis, from the base of the upper Eocene Birket Qarun Formation, based on a partial neurocranium including the complete left side, partial right dentary, left suspensorium, two opercles, left pectoral girdle and spine, nuchal plates, first and second dorsal spines, Weberian apparatus and a disassociated series of abdominal vertebrae. All of the elements belong to the same individual and some of them were found articulated. Qarmoutus gen. nov. is the oldest and the most complete of the Paleogene marine catfishes unearthed from the Birket Qarun Formation. The new genus exhibits distinctive features not seen in other African Paleogene taxa, such as different sculpturing on the opercle and pectoral girdle with respect to that on the neurocranium and nuchal plates, denticulate ornamentation on the skull bones arranged in longitudinal rows and forming a radiating pattern on the sphenotic, pterotic, extrascapular and the parieto-supraoccipital, indentations or pitted ornamentation on the nuchal plates as well as the parieto-supraoccipital process, strut-like radiating pattern of ornamentation on the opercle from the proximal articulation to margins, longitudinal, curved, reticulate ridges and tubercular ornamentations on the cleithrum, sinuous articulation between the parieto-supraoccipital process and the anterior nuchal plate, long, narrow, and arrowhead shaped nuchal shield, very small otic capsules restricted to the prootic. Multiple parsimony and Bayesian morphological phylogenetic analyses of Ariidae, run with and without “molecular scaffolds”, yield contradictory results for the placement of Qarmoutus; the genus is either a phylogenetically basal ariid, or it is deeply nested within the ariid clade containing New World species of Sciades.