Nageh A. Obaidalla

The Dababiya corehole, Upper Nile Valley, Egypt: Preliminary Results

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Planktonic foraminiferal biostratigraphy and faunal turnover events during the Late Cretaceous-Early Tertiary along the Red Sea Coast, Egypt

Abstract Planktonic foraminiferal assemblages from the Late Cretaceous-Early Tertiary sedimentary sequence in Quseir (Hammadat section), Safaga (Wasif section) and Esh El-Mellaha (Esh El-Mellaha section) areas along the Red Sea Coast, provide a database for biostratigraphical subdivisions and marking of faunal changes. Ten planktonic foraminiferal zones were found. There are, from base to top, the Late Cretaceous Globotruncana aegyptiaca and Gansserina gansseri Zones and the Early Tertiary Parasubbotina pseudobulloides, Praemurica trinidadensis, P. uncinata, Morozovella angulata, Igorina pusilla, Globanomalina pseudomenardii, Morozovella velascoensis and M. edgari zones. Two intervals of non-deposition of sediments (hiatuses) in the study areas are recorded, indicating tectonic events. The first hiatus occurred all over the study areas near the Cretaceous/Tertiary boundary. The second hiatus is restricted to the Late Palaeocene of the Safaga area. Two global planktonic foraminiferal faunal turnover events are identified, reflecting major palaeoceanographic changes. The faunal turnover event I occurred near the M. angulata/I. pusilla boundary near the Palaeocene/Eocene boundary. These turnovers are characterised by the appearance and disappearance of species and changes in relative abundance, diversity and richness of species. Oscillation in the mean sea level in the study areas during the Late Cretaceous-Early Tertiary may be related to a true eustatic change in addition to the evidence for local tectonic control.

High-resolution sequence stratigraphy of the Upper Cretaceous-Lower Paleogene succession, Gabal Qreiya area, Upper Egypt

The Upper Cretaceous-Lower Paleogene succession at Gabal Qreiya area that covers six rock units, Quseir, Duwi, Dakhla, Tarawan, Esna, and Thebes formations, is reviewed through a high-resolution sequence stratigraphic analysis. Six third-order depositional sequences and their associated surfaces and systems tracts are recognized based on stratigraphic, sedimentological, and high-resolution foraminiferal studies. The pre-Campanian sequence, comprising the Quseir Formation, was accumulated in inner neritic paleodepths, on marginal to shallow subtidal shelf. The Lower Campanian sequence that covers the Duwi Formation was accumulated in oscillating settings between inner to middle neritic paleodepths, on a shallow subtidal shelf. The Upper Campanian-Maastrichtian sequence that covers the lower part of the Dakhla Formation was accumulated in outer neritic-upper bathyal to middle neritic paleodepths, on a deep subtidal shelf to a shallow subtidal shelf. The Danian sequence that covers the middle part of the Dakhla Formation was accumulated in oscillating conditions between upper bathyal and middle neritic paleodepths, on a deep subtidal and a shallow subtidal shelf. The Selandian-Thanetian sequence that comprises the upper part of the Dakhla, Tarawan, and the lower part of the Esna formations was accumulated in fluctuating conditions from upper bathyal to middle neritic paleodepths, on a deep subtidal to a shallow subtidal shelf. The Ypresian sequence that includes the main parts of Esna and Thebes formations was accumulated in fluctuating settings among middle bathyal and middle neritic paleodepths, on a deep subtidal to a shallow subtidal shelf. Most of the sequence boundaries coincide with the global sea-level curve whereas some of them suggest a local tectonic event.

Mid-Paleocene event at Gabal Nezzazat, Sinai, Egypt: planktonic foraminiferal biostratigraphy, mineralogy and geochemistry

The Qreiya Beds that record the ‘mid-Paleocene event’ at Gabal Nezzazat occur within the Igorina albeari (P3b) Zone and constitute part of a 14-m thick shale succession that ranges in age from Early to Late Paleocene. They are composed of four alternating dark grey and brown shale beds, which are thinly laminated, phosphatic, organic-rich and extremely sulphidic. They are characterized by distinct enrichment and high peak anomalies in chalcophiles (Zn, Co, Ni, Cu and Pb) and organic association elements (V and Cr), especially within the brown organic-rich beds. It is concluded that these elements are incorporated into the phosphatic debris, sulphides and organic matter. In contrast, the grey beds are enriched in clay minerals and quartz. Clay mineral assemblages indicate alternating periods of warm/humid climate (high kaolinite) and dry climate (low kaolinite) during the formation of the grey and brown beds, respectively. The sediments of the Qreiya Beds yield lithological, biotic, geochemical and mineralogical data indicative of suboxic/anoxic marine environments as a result of high productivity and/or upwelling. The top metre of the succession below the Qreiya Beds is characterized by a progressive change from faunas dominated by praemurcurids to faunas dominated by Morozovilids, and by a progressive upward decrease in δ13Ccarb and δ18Ocarb values. The foraminiferal faunal change may reflect shallowing and warming preceding deposition of the Qreiya Beds. The change in isotopic values is inferred to be the result of surface weathering, fluvial input and diagenesis with no evidence of any primary change that could support presence of a hyperthermal event.

The impact of the Syrian Arc Orogeny on the evolution of the Lower Paleogene sedimentary basin in Sinai, Egypt

A regions are affected by many environmental challenges such as the absence of vegetation cover, lack of rain fall, increase wind erosion, which eventually increases sand and dust storm events. The upper surface of soil is vulnerable to land degradation causing the accumulation of sand around building, roads, and different man made infrastructure that cost the country tremendous amount of money yearly for mechanical sand removal. The cost of mechanical sand removal is 5.20 USD for 1 m3. Therefore, this study focuses on three different types of nabkhas namely; single plant, double plants and group of plants nabkhas. The physical and chemical properties of nabkha i.e., particle size, organic matter, moisture content, acidity, electrical conductivity were also covered. The volume of trapped sand accumulated around nabkhas are measured in cubic meters (m3), and converted to calculated cost of mechanical sand removal. A single nabkha of Nitraria retusa, is capable of trapping mobile sand with a maximum of 21.9 m3 and an average of 2 m3. The equivalent cost of trapped sand in forming single nabkha is 10.4 USD. Hence, the efficiency of native plant species in trapping mobile sand reduces the cost of sand removal in the different forms of nabkhas. Therefore, Nitraria retusa as a dominant native plant in Kuwait represents valuable and efficient control measure for mobile sand and dust.G is recovered from gold ores. Within the ores, there are not only gold but also several types of precious metals. Copper, silver, and platinum group elements (ruthenium, rhodium, palladium, rhenium, osmium, and iridium) are metals commonly found in the ores. These metals combine to form an ore because they have the same properties. It is due to their position in periodic-system-of-elements which are near to gold. However, there is no previous study that mention the presence of mercury in every gold ores, even though it is located right next to gold in the periodic-system-of-elements and they are located in the same block, d-block. But, it is possible that mercury is contained in the ores. Moreover, the elements of the same group with mercury-zinc and cadmium-sometimes can be found in the ores. It is suspected that mercury cannot be detected because the processing of gold ores is usually done using fire assay method. Before the ores melt, mercury would evaporate because it has the lowest boiling point when compared to all precious metals in the ores. Therefore, it suggested to do research on the presence of mercury in gold ores using CVAAS method. The results of this study would obtain the amount of mercury in gold ores that should be purified. So it can be produced economically if possible.