Original paper
Biostratigraphy and paleoenvironmental dynamics of the Campanian–Paleocene macrofossils in the Kharga Oasis, Western Desert, Egypt
Moneer, El Sayed M.; Hewaidy, Abdel Galil A.; El Qot, Gamal M.; Bazeen, Youssef S.
Palaeontographica Abteilung A (2026)
95 references
published online: Feb 20, 2026
manuscript accepted: Feb 4, 2026
manuscript received: Nov 18, 2025
DOI: 10.1127/pala/0175
Abstract
The Campanian–Paleocene interval in the Kharga Oasis, Egypt, offers critical insights into biotic and environmental dynamics during a period marked by sea-level fluctuations. This study investigates macrofossil assemblages from three sections: Naqb El Rufuf, Um El Ghanayim, and Baris, reflecting north-south facies changes to unravel biostratigraphic and paleoecological trends. Eight distinct macrobenthic associations were identified, each reflecting unique environmental conditions tied to sequence-stratigraphic phases. During the Campanian, the Glossus chargehensis association in the Duwi Formation signals shallow, nutrient-rich transgressive settings with phosphate deposition under well-oxygenated conditions. The Maastrichtian Exogyra overwegi association, preserved in high-energy carbonate ledges of the Baris Oyster Member, marks episodic sea-level rises and firm substrates. The early Danian records the first post-K-Pg transgression, characterized in the north by reworked Maastrichtian faunas and in the south by monospecific Crassostrea orientalis beds, suggesting salinity stress and limited biotic competition. As sea level continued to rise, the northern Kharga Basin developed oxygen-depleted, iron-rich conditions favoring dwarf faunas, while the southern Garra El-Arbain facies hosted stable Venericardia and Turritella communities in shallow, well-oxygenated waters. In the upper Paleocene Tarawan Formation, the lower portion hosted the semi-infaunal echinoid Echinocorys fakhryi in chalky limestone, outer neritic facies. The top portion of the Tarawan Formation featured the dominance of the siliceous sponge Schizorhabdus libycus—a shift linked to the Selandian/Thanetian transition and increased silica influx, which may have altered ocean chemistry. Macrofaunal distributions in the Kharga Oasis closely mirror sequence‐stratigraphic phases, with transgressive systems tracts promote diverse suspension-feeder assemblages in nutrient-rich settings, while highstand systems tracts favor stress-tolerant or siliceous taxa under more stable, low-energy conditions.
Keywords
Macrobenthic associations • biostratigraphy • paleoecology • Campanian–Paleocene • Kharga Oasis