• Maha Mohamed Mahmoud

The Late Cretaceous Period was characterized by nutrient-rich conditions driven by intense coastal upwelling. This upwelling system, fueled by strong coastal winds, particularly during the Maastrichtian, elevated nutrient levels in surface waters, as evidenced by geochemical proxies and benthic foraminiferal data. Benthic foraminifera, widely used as indicators of past ocean depths and depositional environments, were studied in the Campanian-Maastrichtian (C-M) marine rocks of the Sudr Formation from the Gabal Nezazzat section (west-central Sinai, Egypt). Nine planktonic foraminiferal zones are recorded through the Nezzazat section, ranging from CF9 to CF1. A total of 71 samples, comprising 69 species across 35 genera, were analyzed to infer species diversity, interrelationships, and changes in palaeo-environmental conditions, palaeo-oxygenation, palaeo-productivity, and palaeo-depth within the C-M successions. The Campanian deposits were formed in outer neritic to upper bathyal environments (201.6–539.84 m), characterized by low organic matter flux (HOFS: 4.5% to 9%), low total organic carbon (TOC < 3), and well-oxygenated conditions (BFOI: 33.3 to 67.3; oxic >0.3 mL/L O₂). The transition from the Campanian to the Maastrichtian occurred in outer neritic to deeper bathyal settings, maintaining low productivity and well-oxygenated conditions. Early Maastrichtian deposits indicate shallower depositional environments (113.5–479.75 m) with reduced oxygen availability at the seafloor (BFOI: 40–60; dysoxic 0.1–0.3 mL/L O₂), associated with increased organic matter flux and higher TOC values (>4). These conditions deepened through the late Maastrichtian, with upwelling-driven nutrient enrichment persisting throughout the period

low-oxygen, Campanian-Maastrichtian, Gebel Nazzazat, Sinai, Benthic foraminiferal

"CHARACTERIZATION OF LOWEST OXYGEN ENVIRONMENTS WITHIN ANCIENT UPWELLING ENVIRONMENTS: A CASE STUDY FROM THE CAMPANIAN-MAASTRICHTIAN AT WEST-CENTRAL SINAI, EGYPT", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 3, page no.b173-b200, March-2025, Available :http://www.jetir.org/papers/JETIR2503121.pdf

"CHARACTERIZATION OF LOWEST OXYGEN ENVIRONMENTS WITHIN ANCIENT UPWELLING ENVIRONMENTS: A CASE STUDY FROM THE CAMPANIAN-MAASTRICHTIAN AT WEST-CENTRAL SINAI, EGYPT", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 3, page no. ppb173-b200, March-2025, Available at : http://www.jetir.org/papers/JETIR2503121.pdf