Upper Campanian–Maastrichtian chronostratigraphy of the Skælskør‐1 core, Denmark: correlation at the basinal and global scale and implications for changes in sea‐surface temperatures

Abstract

The lithostratigraphy, calcareous nannofossil biostratigraphy, carbon‐ and oxygen‐isotope stratigraphy and gamma‐ray profile are presented for the Skælskør‐1 core, eastern Denmark. The correlation of carbon isotopes to Gubbio (Italy) and ODP Site 762C (Indian Ocean) provides the chronostratigrahical framework of the core through a tie to magnetostratigraphy. Two new carbon‐isotope excursions are defined for the uppermost Maastrichtian of the core and prove useful for long‐distance correlation. Twenty stratigraphic tie‐points are used for correlation of the upper Campanian–Maastrichtian interval by combining carbon‐isotope and gamma‐ray variations. Significant dissimilarities in the gamma‐ray profiles of the Danish Basin cores preclude the sole use of this tool for basin‐scale correlations. Bulk oxygen‐isotopes and semi‐quantitative abundance changes in the warm‐water calcareous nannofossil Watznaueria barnesiae and the cool‐water Kamptnerius magnificus highlight the following past changes in sea‐surface temperatures (SSTs): relatively warm late Campanian SSTs, cooling across the Campanian–Maastrichtian boundary and through the early Maastrichtian, warming across the early–late Maastrichtian transition, cooling in the late Maastrichtian, intense warming in the latest Maastrichtian chron C29r, followed by a very short episode of cooling immediately before the Cretaceous–Palaeogene boundary. The late Campanian–Maastrichtian evolution in sea water temperatures inferred from the Danish Basin is similar to that delineated at tropical latitude oceanic sites.

Upheavals during the Late Maastrichtian: Volcanism, climate and faunal events preceding the end-Cretaceous mass extinction

“…Decreased diversity and abundance of large complex species can be attributed to decreased water mass stratification associated with the onset of cooling. Calcareous nannofossil assemblages record no obvious change in species richness for the CF4 warm event (Sheldon et al, 2010;Thibault and Gardin, 2006;Thibault et al, 2015b) although a significant decline begins within UC20b near the CF4-CF3 transition in the tropical Pacific and South Atlantic (Thibault and Gardin, 2010). Pardo, 2004;Luciani, 2002).…”

Sinemurian–Pliensbachian calcareous nannofossil biostratigraphy and organic carbon isotope stratigraphy in the Paris Basin: Calibration to the ammonite biozonation of NW Europe

“…Semi-quantitative counts of calcareous nannofossil species were performed with a LEICA DM750P light microscope at a magnification of 1600X (x100 oil objective with a x1.6 additional lens and x10 oculars). Following Thibault et al (2015), a species were classified as abundant (A) if more than 10 specimens were observed in a field of view (FOV); common (C) if 1-10 specimens were observed in a FOV; frequent (F) if one specimen or more were observed in every 10 FOVs; rare (R) if only one specimen was observed in 11-100 FOVs; very rare (VR) if only one specimen was observed in 100-200 FOVs; single (S) if only one specimen was observed during the complete investigation (approximately 300 FOVs). The first and last occurrences (FOs and LOs) have been used, but as described below, many taxa show inconsistent records at the base (and sometimes at the top) of their range.…”

Climatic fluctuations and sea-surface water circulation patterns at the end of the Cretaceous era: Calcareous nannofossil evidence

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 6 2.9 km NNW of the town of Skaelskør (south-western Sjaelland, Denmark, Thibault et al, 2015b). The borehole is located close to the axis of the Rynkøbing-Fyn topographic High.…”