Middle Campanian (Late Cretaceous) sea-level rise; microfossil record of bathymetric changes

Abstract

A Middle Campanian (Late Cretaceous) eustatic sea-level rise recorded in the Belgorod succession (Russia; eastern North European Basin) was analyzed. The succession, dated for the Gavelinella annae and Globorotalites emdyensis foraminiferal zones (corresponding to the ‘Inoceramus’ azerbaydjanensis–‘Inoceramus’ vorhelmensis inoceramid Zone), records the deposition of pure chalk, with only trace terrigenous material. Its distal offshore position limited terrestrial nutrient delivery, driving oligotrophic conditions that influenced benthic foraminifera and organic-walled phytoplankton communities. Eustatic changes are recorded by planktonic foraminifera and additionally reflected in phytoclast abundance, organic-walled dinoflagellate cysts (dinocysts), calcareous dinoflagellate cysts (c-dinocysts), and δ13C and δ18O fluctuations. Most indices were primarily driven by variable terrestrial organic matter and freshwater influxes, acting as a function of sea depth and land topography.