Calcareous nannofossils and other proxies define the Santonian–Campanian boundary in the Central Crimean Mountains (Alan-Kyr section)

A Santonian record of the nautilid cephalopod Angulithes westphalicus (Schlüter, 1872) from the subsurface of the Campine, north-east Belgium, with comments on regional lithostratigraphic problems

“…Translating these biozonal dates into geological time is not straightforward, since diachroneity has been demonstrated for several of the first and last occurrences used to define the zonal boundaries, and basin to basin correlations, even within the Boreal Realm, for the Santonian have proved challenging. However, major advancements have been made in the last decade (see e.g., Thibault et al, 2016;Ovechkina et al, 2020;Miniati et al, 2020;Gale et al, 2021), leading, amongst other things, to the formal definition of a GSSP for the base of the Campanian (Gale et al, 2023), which is in the Bottacione section at Gubbio, Italy, at the 221.53 m level, corresponding to the magnetic polarity reversal from Chron C34n (top of Long Cretaceous Normal Polarity-Chron) to Chron 33r. The reversal, together with the late Santonian event (LSE, previously named Santonian-Campanian Boundary Event, or SCBE) in carbon isotopes and several bio-events (mostly foraminifera and calcareous nannofossils), should allow correlations with other Santonian-Campanian boundary sections worldwide (see Gale et al, 2023 for details).…”