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• Maastrichtian and Turonian deposits stand out as superior hydrocarbon source rocks. • Increased thermal maturity observed in pre-Maastrichtian sediments. • Upper Cretaceous deposits indicate a marine origin and prevalent anoxic conditions. • Organic richness in Maastrichtian/Turonian deposits is tied to upwelling and OAE2. Cretaceous sedimentary successions in Jordan are among the most promising unconventional global petroleum resources. The Upper Cretaceous deposits in the Azraq Basin in Jordan were analyzed using Rock-Eval pyrolysis, stable carbon isotopes, vitrinite reflectance, and biomarkers, as well as 1D basin modeling. This study aims to evaluate source input, depositional environment, burial history and potential for hydrocarbon generation of the Upper Cretaceous organic-rich deposits in Jordan. The Upper Cretaceous samples exhibit variable source rock potential. Maastrichtian samples are very good, primarily oil-prone, while Campanian and Cenomanian samples range from fair to poor, with Turonian samples showing good petroleum generation potential. Thermal maturity analysis of Cretaceous samples reveals higher maturity in Turonian and Cenomanian samples compared to the thermally immature Maastrichtian and Campanian samples based on the maximum temperature of pyrolytic hydrocarbons generation, vitrinite reflectance, production index and biomarker indicators. The molecular fossils data suggest that the organic matter of these source rocks was primarily of marine phytoplankton origin, with considerable contributions from microbial biomass, and deposited under oxygen-depleted bottom water conditions. Additionally, the resemblance in molecular composition between Cretaceous source rocks and crude oil samples suggests a common origin for the hydrocarbons. The highest contents of organic matter have been recorded at the top of the Maastrichtian and at the bottom of the Turonian sections. These findings correspond with Maastrichtian upwelling deposits in North Africa and the Middle East, as well as with deposits from the Cenomanian-Turonian Oceanic Anoxic Event (OAE2). [ABSTRACT FROM AUTHOR]

Paleozoic sedimentary succession research is valuable for better understanding the global petroleum province and future hydrocarbon reserves. Paleozoic rocks are the prime source of the enormous hydrocarbon fields in North Africa. Despite the Western Desert of Egypt being part of the North African Platforms and having similar depositional, tectonic, and diagenetic constraints, the hydrocarbon system for Paleozoic rocks in the Siwa Basin is indeed not characterized. Forty-five Paleozoic samples were collected from the Siwa Basin to evaluate the source rock characteristics using Rock-Eval pyrolysis, vitrinite reflectance, stable carbon isotopes, biomarkers, headspace gas, and palynofacies analyses. Additionally, the burial and thermal histories of these rocks were investigated by 1D basin modeling. The Paleozoic succession is represented by the Silurian (Basur Formation), Devonian (Zeitoun and Desouqy formations), and Carboniferous (Dhiffah Formation). The routine bulk geochemical analysis of the studied samples indicates poor to good source rock potential. The studied samples contain mostly kerogen type III with some kerogen type II, whereas the Carboniferous samples contain mostly kerogen type IV. The organic matter of the Devonian samples is suggested to have originated from marine and terrigenous sources, with a dominant upward terrigenous source. The lower part of the Devonian is deposited in more reduced marine conditions than the upper part. The organic matter is found to be mature, as indicated by Rr%, T max , and biomarker data. The composition of collected headspace gases in Paleozoic rocks suggests their thermogenic origin. Moreover, the similarity of the molecular composition between Paleozoic source rocks and crude oil in reservoir rocks supports the same hydrocarbon sources. Accordingly, the petroleum system in the Siwa Basin is based on active Paleozoic source rocks that charge and accumulate hydrocarbons in the sand reservoirs of the Desouqy Formation. The Paleozoic section entered the oil window in the Early Cretaceous (∼101 myr) based on its burial history. Thus, this study gives improved insights into the petroleum system in the Siwa Basin. Additionally, the Siwa Basin's lesser thickness and burial depth in comparison to other North African basins most likely contributed to its poor petroleum potential. • Paleozoic rocks have poor to good source rock potential. • Organic matter is derived from marine and terrigenous sources. • Source rocks were deposited in a reducing environment. • Paleozoic rocks in Siwa Basin have active source rocks. [ABSTRACT FROM AUTHOR]

The effect of paleoclimate during global warming periods on Upper Cretaceous lacustrine deposits is not fully understood. In this study, comprehensive sedimentological, mineralogical, and geochemical data were used to unravel the past climatic changes and their influence on the accumulation of Campanian lacustrine organic-rich deposits in Egypt. Three sedimentary lithofacies associations are recorded within the uppermost part of the Quseir Formation. The laminated clay-rich mudstone lithofacies has the highest organic matter (TOC up to 1.2 wt.%). Sedimentological observations indicate that the bulk lithologic assemblage was originated in a shallow lacustrine setting. The studied samples consist of clay minerals, quartz, pyrite, carbonate, fluorapatite, and halite. The siliciclastic content reaches up to 78wt.%, whilst the carbonate content ranges from 3 to 22 wt.%. Compared to Post-Archean Australian shales (PAAS), the studied samples are significantly rich in Mg, Ca, P, Al, V, Ga, and Cr contents. The mudstone samples are characterized by high ratios (C-value, CIA, CIW, Mg/Ca, Fe/Mn, Ga/Rb) and low values (K 2 O/Al 2 O 3), reflecting relatively warm and humid conditions during deposition of these sediments. The prevalence of smectite, as well as the sedimentary features, support that the lacustrine organic-rich mudstones are mainly deposited under warm seasonal climate (arid/humid). Additionally, the presence of dolomite and halite along with the Sr/Ba ratios (1.30–2.13), strongly suggest a saline water setting. The changes between aridity and humidity periods are probably the main reason for the significant variation in water chemistry, especially salinity. Therefore, the paleoclimatic variations largely controlled the depositional process during the formation of the Upper Cretaceous lacustrine organic-rich mudstones in the southern Tethys. • Geochemical and mineralogical data show a prevailing warm seasonal climate. • The studied samples deposited in a shallow saline lacustrine setting. • Water chemistry controlled by climatic changes. [ABSTRACT FROM AUTHOR]

• Dating the GMG granitic phase as a typical example of aqueous silicate magma. • Laser ablation zircon U-Pb results yield imprecise to meaningless dates. • Pristine (Mnz1) and altered (Mnz2) yield similar electron microprobe (EMP) chemical ages of ca.587 Ma. • Thorite chemical age (592 ± 8 Ma) is within analytical error of associated magmatic monazite. • The two monazite ages indicate alteration/replacement occurred during or soon after crystallization of the pluton. We present the first chemical age determination of monazite from a geochemically-specialized rare metal granite of the Central Eastern Desert (CED), Egypt. The Abu Diab composite A-type granite of the CED divides into three co-magmatic phases: two mica granite (TG), garnet-bearing muscovite granite (GMG), and muscovite granite (MG). The GMG granitic phase is a typical example of a rare metal, volatile-rich aqueous silicate magma. Its zircon has extremely high U-concentration (up to 45,000 ppm) and intense metamictization, resulting in significant radiogenic Pb-loss, as well as common Pb contamination, along fractures and other imperfections. Laser ablation (LA-ICP-MS) zircon U-Pb results yield imprecise to meaningless dates. On the other hand, the GMG exhibits two texturally and chemically distinct varieties of monazite, pristine (Mnz1) and altered (Mnz2), that yield similar electron microprobe (EMP) chemical ages of 587 ± 8 Ma (2σ) for Mnz1 and 587 ± 9 Ma (2σ) for Mnz2. These ages, combined with the inferred alteration temperature (T > 400 °C), indicate monazite alteration/replacement occurred during or soon after crystallization of the pluton, in response to expelled magmatic-hydrothermal fluids inferred to be F-rich, late-staged deuteric fluids. The alteration and elemental substitution of zircon and monazite reflect coupled dissolution-recrystallization processes during late-staged deuteric alteration when zircon and thorite were relatively vulnerable to post-magmatic hydrothermal effects because of their extremely metamict state. The ca. 587 Ma age is typical of A-type granite intrusion across the CED and the post-collisional stage of the Arabian Nubian Shield (ANS; 610 – 560 Ma), and is within analytical error of associated magmatic thorite (592 ± 8 Ma). These two ages agree with the timing of rare metal-rich intrusions (0.6−0.4 Ga) related to the Pan-African orogeny. Future research using the monazite chronometer may better constrain the timing of rare metal granitic magmatism of the ANS. [ABSTRACT FROM AUTHOR]

In the last 5 decades, paleontological research has exploded where fossils have enabled robust dating of rocks, improved understanding of origination/extinction rates or mass extinction events, biogeography, adaptive strategies, and many more. New molecular technologies have enabled intensive analyses of vertebrates and invertebrates, plant fossils, fossilized microbes, trace fossils, and fossil molecules, alike. Paleontological research has become interdisciplinary with inputs from geology, chemistry, biology, astronomy, and archaeology. Herein, we review the principles of promising molecular technologies and explore their applications and limitations vis-à-vis paleontological research. This review will attempt to provide a roadmap that can be used for future research directions. Advanced chemical imaging provides the ability to identify and quantify chemical characteristics to evaluate taphonomic damage, original biological structures, or fossils microbes. Molecular methods (e.g., molecular clock, DNA barcode, racemization dating, and biomarkers) offer a unique source of information and provide robust clues into the co-evolution of life in modern and past environments. Two main limitations are noted and include an exceptional preservation of the organic material, which is not always the case, and the complexity and cost of the instruments involved in the analyses. These difficulties are limiting the factual applications in paleontological analysis. Although very little research has been carried out on the aforementioned methods, they however, provide improved answers to highly debated and unsolved biological and climatic issues and a window to better understanding the origin of life. Biomarker proxies will be further developed and refined to answer emerging questions in the Quaternary Period. [ABSTRACT FROM AUTHOR]

The current investigation aims to assess the potential of El-Yatima granitic pluton as a decorative stone by examining its natural radioactivity and mineralogical elements. Specifically, the study aims to determine the concentrations of radionuclides 40K, 232Th, and 226Ra, perform petrographic analyses, and evaluate the associated radiological risks to determine the safety and usability of the granite in construction and decoration, as well as to assess the potential of these granitic rocks as a safe and effective decorative stone for various applications. It has a 12 km2 surface area of 812 m above sea level. It is situated in the Eastern Central Desert. Its hypidiomorphic texture, medium-to-coarse grain size, and predominant composition of K-feldspars, quartz, and plagioclase are observed, along with minute amounts of muscovite and biotite. By employing NaI (Tl) gamma-ray spectroscopy, the natural radionuclide concentrations of 40K, 232Th, and 226Ra in El-Yatima granitic rocks were ascertained. Additionally, radiological concerns were identified for the materials that were examined. The average concentrations of radionuclides 40K, 232Th, and 226Ra are 178 Bqkg−1, 44 Bqkg−1, and 41 Bqkg−1, respectively. The following are the computed values: 117 Bqkg−1, 0.43, 0.32, 53 nGyh−1, average radium equivalent (Raeq), hazard indices (H in and H ex) and dose rate (D), respectively. When compared to levels typically indicated, it was discovered that its values were within the worldwide standard. The study's findings could be a starting point for radiometric data for upcoming surveillance and epidemiological research. • "El-Yatima granitic rocks exhibit natural radioactivity within global safety standards.". • "Gamma-ray spectrometry reveals elevated 226Ra and 232Th in El-Yatima granite.". • "Granitic samples show average radionuclide concentrations suitable for decorative use.". • "Comprehensive radiological assessments indicate low public health risk from El-Yatima rocks.". • "Study provides baseline data for future radioactive surveillance in the Central Eastern Desert.". [ABSTRACT FROM AUTHOR]

[Display omitted] • The volcanic rocks in the Gabgaba Terrane were erupted during Tonian. • The volcanic rocks have positive εHf(t) values, indicative of derivation from a juvenile arc magmatism. • The depleted mantle source was metasomatized by slab-dehydration fluids. • The primitive magma was subjected to crustal assimilation prior to eruption. • The volcanic rocks were erupted during different stage of arc maturity. An integrated study of zircon U-Pb geochronology and geochemistry together with Lu-Hf isotopes, has been carried out on basaltic andesite and andesite from the Haweit area (Gabgaba Terrane, NE Sudan) to indicate their magmatic evolution. In-situ U-Pb zircon dating yielded a weighted mean age of 752 ± 11 Ma for andesite and 773 ± 17 Ma for basaltic andesite, suggesting they were generated during Tonian. The Haweit volcanic rocks are generally sub-alkaline and tholeiitic lavas. They are characterized by low Mg# (29–44), low TiO 2 (0.70–1.41 wt%), and relatively high Al 2 O 3 (14.60–18.30 wt%) indicating that they are not a primitive melt. The nearly flat REEs pattern of the basaltic andesites indicate that they were formed in an immature island arc setting. While andesites are slightly enriched in LREE and LILEs, suggesting more mature island arc setting. The calculated Hf-T DM C (0.87–1.6 Ga) ages of zircons preclude the possibility of interaction of the parental magma with a pre-Neoproterozoic crustal source. The low (La/Yb) N (0.73–9.56) and high Zr/Nb (33–62) ratios, along with positive εHf(t) values (+1.33 to +12.5) indicate that the Haweit volcanic rocks were originated from depleted mantle with little crustal contamination. The geochemical data suggest that the parent magma of the Haweit volcanic rocks could be formed by low degree partial melting of spinel‐bearing Iherzolite depleted mantle metasomatized by slab‐derived fluids. The Haweit andesitic melts were later subjected to crustal assimilation before the final eruption of lavas during two stages of arc evolution. [ABSTRACT FROM AUTHOR]

Understanding the response of the benthic invertebrates to long-term sea-level changes, which is possible only from the fossil record, is crucial for conservation biology. Based on integrated sedimentological and biostratigraphical data from the Cenomanian-Turonian succession of Wadi Tarfa (Eastern Desert, Egypt), a cyclic pattern, comparable to those of 2nd order sequence stratigraphy, between the community structure of the invertebrates and the sea-level fluctuations was revealed. Quantitative analysis of 1756 specimens representing 154 invertebrate genera encompassing mollusks and echinoid revealed that invertebrate communities can be classified into three different types. The first associated with the initiation of transgression (TST) and dominated mainly by opportunistic, epifaunal suspension-feeders, including gastropods and bivalves. This community is characterized by lower diversity values. The second community belonged to the maximum flooding zone (MFZ) and mainly dominated by infaunal deposit-feeders of irregular echinoids and bivalves and characterized by higher diversity. The last community is less diverse, dominated by few epifaunal-suspension feeders and occupying the late highstand system tract (HST). The lower diversity values during the early TST/late HST may result from the persistence of waves/the higher sedimentation rates. Consequently, only opportunistic taxa flourished. In contrast, diversity increases with flooding and is at a maximum and dominance at a minimum at the transgression peak (MFZ). Here, the high diversity, which is commonly augmented by time-averaging, most likely contributed also to the environmental stability, which increases with flooding. Accumulation of biogenic hardparts in combination with low rates of sedimentation may increase substrate heterogeneity and thus increases beta diversity (niche differentiation). The cyclic pattern of the community attributes results from the hydrodynamic setting accompanying the sea-level changes. The role of ecoenvironmental and taphonomic mechanisms in shell concentrations are also discussed. Image 1 • The community structure has a cyclic pattern comparable to the sequence stratigraphic architecture. • Biodiversity increase with increasing flooding and be of maximum at the maximum flooding zone. • The faunal variations are driven mainly by sea-level fluctuations and hydrodynamics. • The ecoenvironmental and taphonomic mechanisms in shell concentrations were specified. [ABSTRACT FROM AUTHOR]

The central Eastern Desert (CED) of Egypt is well-known for its granite-related Nb–Ta mineralization. The garnet-bearing muscovite granite (GMG) of the Abu-Diab composite pluton in the CED consists mainly of quartz, K-feldspar (Or 88–98), albite (An 0-4) and muscovite, with accessory minerals including garnet, zircon, columbite, ilmenite, Ti-rich hematite, rutile, ilmenorutile, thorite, apatite, xenotime and chlorite. The GMG is weakly peraluminous and has low Nb/Ta (9.6–15.4) and Zr/Hf (16–31) with discernible REEs tetrad effect (TE 1-3 = 1.11–1.35), typical of highly evolved granites. Zircon contains high concentrations of U and Th typical of late-magmatic zircon and similar to zircon type from highly evolved granite. The homogenous and weak zoned columbites are classified as manganocolumbite. The formation of Ta-rich rim in the columbite may indicate that later fluids were from the GMG granite itself at advanced fractionation into exsolving fluids, and not from an external source. Ilmenite is greatly enriched in MnO, which indicates the significant pyrophanite (up to 29 mol %) molecules in ilmenite through simple substitution of Mn for Fe2+ with increasing oxygen fugacity under magmatic-hydrothermal conditions. Xenotimes show low analytical totals, suggesting probably hydration during their post-magmatic alteration, while apatite is small-grained associated with tiny zircons, suggesting late-crystalized phases. During late magmatic differentiation stage, the interaction of granitic melt with F-rich late magmatic fluids could be resulted in the formation of Ti–Nb–Ta–Zr minerals. Overall, the Abu Diab GMG possesses mineralogical and geochemical features that make it a potential target for Ti–Nb–Ta–Zr minerals. Image 1 • The highly evolved granitic phase in the Abu-Diab composite pluton contains significant Ti-Nb-Ta-Zr bearing minerals. • Zircon shows a feature of late-magmatic type with high U and Th contents. • The columbite-Mn is homogenous to weakly zoned of magmatic origin. • The F-rich late magmatic fluids play a vital role in the formation of the Abu-Diab Ti–Nb–Ta–Zr minerals. [ABSTRACT FROM AUTHOR]