A benthic foraminiferal record of Paleocene sea level and trophic/redox conditions at Gebel Aweina, Egypt

We quantitatively analyzed benthic foraminiferal assemblages in order to reveal biotic and paleoenvironmental trends in the Paleocene section of Gebel Aweina, Egypt, on the southern Tethyan shelf. The first correspondence axis ranks taxa along an empirically derived bathymetric gradient, with neritic taxa (e.g., Discorbis duwi and Haplophragmoides walteri) opposed to bathyal taxa (e.g., Nuttallides truempyi and Gavelinella beccariiformis). The estimated paleodepth, as reflected by the various assemblages, was mostly ∼ 200 m, but varied between ∼ 50 m (P3a, NP4) and ∼ 300 m (P4, NP8). The resultant four relative sea-level cycles appear to be at least of regional extent and may in part be eustatically controlled. The second correspondence axis reflects trends in trophic and redox development. Low-food, high-oxygen conditions prevailed during Biochrons P1c–P3b (NP4–NP5) and late P4 (NP8), when assemblages were mostly dominated by Cibicidoides spp. Most oligotrophic conditions coincided with maximum paleodepth. Intermediate trophic levels were established during middle P4 (NP6) and early P5 (NP9). From the level of the latest Paleocene benthic extinction event (BEE; middle P5 and NP9) onwards until Biochron P6a (NP10), assemblages dominated by buliminids marked increased trophic levels and reduced ventilation, probably resulting from enhanced surface productivity. Enhanced surface productivity along the southern Tethyan margin started during Biochron P4, and, at least on some shelves, intensified after the BEE. Increasing productivity during the latest Paleocene contrasts with global trends. This may be expected during climatic warming and an expanding trophic resource continuum, leading to regionally intensified eutrophy and oligotrophy. High productivity through upwelling along the southern Tethyan provides support for GCM predictions of intense wind-stress in this region during the warm late to latest Paleocene.