Cretaceous–Paleogene (K–Pg) boundary in south Sinai, Egypt: Paleoenvironment and sequence stratigraphy implications

Abstract

High-resolution quantitative analysis of the benthonic foraminifera throughout the K–Pg boundary interval on four sections (Wadi Nukhul, Abu Qada, Thamad, and Sudr Al Hitan) in south Sinai, Egypt was conducted. Planktonic foraminiferal biostratigraphy indicates a complete K–Pg boundary interval in W. Nukhul section, while minor hiatuses characterized the other sections. Benthonic foraminifera reflect outer neritic-upper bathyal setting for the studied interval, while outer neritic setting marks the latest Maastrichtian. The upper Maastrichtian assemblage indicates mesotrophic to slightly eutrophic marine conditions. At the K–Pg boundary in W. Nukhul, benthonic foraminifera display a significant turnover. A major change in the benthonic foraminifera assemblage which is marked by a decrease in the infaunal taxa and buliminids indicates a shortage in the food supply to the sea floor at the K–Pg boundary. This pattern was associated with increased abundance of the epifaunal taxa indicating oligotrophic conditions that linked to the food web collapse due to extinction of the marine primary producers. A partial recovery of the benthonic foraminifera was observed in the early Danian (Pα and lower part of P1a zones). A comparison between the data of the present study and other K–Pg boundary sites in the Tethyan realm indicates a similar shortage in the food supply with no oxygen deficiency. Two third-order sequences were identified in the studied interval based on the biotic attributes of the fauna. The obtained sea level curve was compared to the global sea level curve.