NEW ARTICLE PUBLISHED ONLINE!

Reassessment of the Salzgitter-Salder section as a potential stratotype for the Turonian–Coniacian boundary: stable carbon isotopes and cyclostratigraphy constrained by calcareous nannofossils and palynology

Silke Voigt, Tobias Püttmann, Jörg Mutterlose, André Bornemann, Ian Jarvis, Martin Pearce and Irek Walaszczyk

Abstract. The abandoned limestone quarry section at Salzgitter-Salder in Germany is a potential candidate for the GSSP (Global Boundary Stratotype Section and Point) of the base of the Coniacian. We present a new high-resolution carbon isotope curve of carbonates (δ13Ccarb) from across the Turonian–Coniacian boundary horizon (TCB) that allows for the precise definition of the Navigation Carbon Isotope Event relative to the occurrences of calcareous nannofossil, organic-walled dinoflagellate cyst (dinocyst) and inoceramid index taxa. The Navigation Event offers a robust global chemostratigraphic marker for the Turonian–Coniacian boundary. A series of subsidiary positive δ13Ccarb events have the potential to serve as markers for regional correlation. Namely, the carbon isotope events i5, i6, and i7 can be used to correlate Salzgitter-Salder to the Běchary Bch-1 core in Bohemia. Spectral analysis shows that these small-scaled peaks are related to high-amplitude signals of precession, confirming an orbital control on δ13C variability. Further, these results indicate a duration of about 100 kyr for the Navigation Event. Carbon isotope and calcareous nannofossil correlation of epicontinental-sea records in Europe and the oceanic record of ODP Site 1259 in the tropical western Atlantic place the Turonian–Coniacian boundary within nannofossil zones CC13 and UC9c. An acme occurrence of the calcareous nannofossil Marthasterites furcatus occurs a short distance above the Navigation Event in Salzgitter-Salder, Bohemia and at Site 1259. An abundance minimum of the dinocyst Palaeohystrichophora infusorioides followed by a marked influx of the taxon coincides with the M. furcatus acme in the European sections. These events offer potential additional markers for the stage boundary.

Newsletters on Stratigraphy (Published online 4th September 2020)
https://dx.doi.org/10.1127/nos/2020/0615