Gebel Nezzi (Upper Nile Valley, Egypt) was chosen to study the middle Palaeocene planktonic foraminiferans, nannoplankton contents, benthic foraminiferans, and stable isotopes to provide additional information into sea‐level changes. Two negative excursions are recorded that are associated with a sharp change in palaeoenvironmental conditions, representing significant global palaeoceanographic, palaeoclimatic, and eustatic events observed at other sites around the world. They are characterized by a drop in total foraminiferal abundance associated with a drop in the type, species richness, frequency, and diversity of foraminifers. The first negative excursion of −0.6‰ δ13C and −0.5 δ18O occurs during the Late Danian Event (LDE) almost near the upper part of the planktonic foraminiferal P3a Subzone and within the calcareous nannofossil NTp8A Subzone at the top of the lower third of Chron C26r. It is dominated by shallow‐water benthic foraminiferans of the Neoeponides duwi biofacies. The Danian‐Selandian boundary lies directly above the LDE within the top of the nannofossil Zone NP4, and within the planktonic foraminiferal Subzone P3b with significant increases in angular morozovellids associated with the earliest Cenozoic hyperthermals. The second negative excursion of −0.6‰ δ13C and −2.2 δ18O occurs near the top of the Dakhla Formation and is dominated by the benthic foraminiferal Bulimina farafraensis biofacies within the upper part of the calcareous nannofossil NTp9 Subzone and upper part of the planktonic foraminiferal P4a Subzone. These negative excursions associated with a well‐known falling sea level and are an important tool for regional correlation. Fluctuations in the foraminiferal population, benthic biofacies, δ 13C and δ18O isotopes and carbonate content reflect three fourth‐order transgressive–regressive (T–R) sequences response to eustatic changes in the Egyptian stable tectonic shelf.
Maastrichtian‐early Paleocene foraminiferal palaeobathymetry, palaeodiversity and vertical facies changes of Gebel El Sharawna, south Luxor, Egypt have been studied to determine the depositional sequences, their relationships to global records and/or tectonic signatures. Five benthonic assemblages are recorded and replicated in the present study reflect fluctuation in palaeo‐water depth from restricted marginal marine to outer shelf palaeoenvironments. Four sequence boundaries that coincide with the Campanian/Maastrichtian, intra‐early Maastrichtian, Early/Late Maastrichtian, Cretaceous/Palaeogene (K/Pg) and intra‐Danian were recognized based upon sharp vertical facies changes, foraminiferal assemblage changes, hiatuses, mineral hard ground and reworking. The K/Pg unconformity reveals an unexpected ca. 4.2 Myr time gap as indicated by the absence of the CF2 Zone through lower part of the P1c Zone. It is easily distinguished in the field by conglomeration and winnowing of phosphate and glauconite in the lower Paleocene. These sequence boundaries defined five third‐order depositional sequences mainly developed as the result of the eustatic sea‐level changes, coupled with the Arabian–Nubian shield tectonic uplift at the southern edge of the Tethys Ocean.
The present work aims to provide a high-resolution stratigraphic range of the planktic foraminiferal group during the Campanian/Maastrichtian boundary (C/M) of Gebel Owaina, Nile Valley. We use the base of Planoglobulina acervulinoides (CF7c Subzone) to mark the C/M boundary, where the planktic foraminiferal assemblages in the subzone are proposed as indicative of the early Maastrichtian age. Five zones (CF9-CF5) and three subzones (CF8a, CF8b, and CF8c) were recognized in the present study. A morphogroups scheme for the calcareous benthic foraminifera used in this work comprises five morphogroups, observed in the Owaina section. Three planktic morphogroups can be recognized and indicate open marine conditions with a good connection to the Tethys Ocean due to the highly diverse Maastrichtian assemblage and high P/B ratio (% P > 95).
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