Sea-level reconstruction for Turonian sediments from Tanzania based on integration of sedimentology, microfacies, geochemistry and micropaleontology

The TDP 31 age model is refined through inter-regional comparison of planktic foraminiferal ranges and δ13C records from three other South-Tethyan localities (ODP Holes 762C and 763B, Exmouth Plateau, and the Guru section, Tibet). This age model enables correlation of the regressive events at a global scale and suggests that, within stratigraphic uncertainty, the TDP 31 depositional sequences are synchronous with the global Turonian third-order sequences and are likely driven by eustasy. These correlations, together with recent astrochronological and radiometric dating, indicate a considerably younger age (91.17 ± 0.52 Ma) for the top H. helvetica Zone than currently assumed, resulting in zonal duration of 2.35 ± 0.52 myr. Foraminiferal stable-isotope data from TDP 31 indicate slight surface- and bottom-water warming during the regressions and possibly a minor surface-water salinity decrease, which is inconsistent with glacio-eustatic forcing of Turonian third-order sea-level cycles and is more in line with the model of aquifer-eustasy.