Upper Campanian-lower Maastrichtian integrated carbon isotope stratigraphy and calcareous microplankton biostratigraphy of North-central Tunisia

Palaeoenvironmental changes across the Mid‐ and latest Maastrichtian events: Planktic foraminiferal inference from the Elles section (central Tunisia)

“…The base of this zone is not reported herein, but P. acervulinoides is reported below the studied interval (at sample no. 220; see Farouk et al, 2021). The LO of Racemiguembelina powelli is reported in the lowermost part of the studied succession at sample no.…”

“…This zone is defined from the LO of P. acervulinoides to the LO of Racemiguembelina fructicosa (Farouk et al, 2021; Nederbragt, 1991). The present P. acervulinoides Zone is correlated with the Pseudotextularia intermedia Zone as introduced by Nederbragt (1991), which is constrained by the LO's of P. acervulinoides and R. fructicosa (Figure 3).…”

“…4.1.1 | Planoglobulina acervulinoides (CF5) Zone (sample nos. This zone is defined from the LO of P. acervulinoides to the LO of Racemiguembelina fructicosa (Farouk et al, 2021;Nederbragt, 1991).…”

“…Thus, documenting these changes enables a better understanding of marine dynamics during the Maastrichtian. However, such studies are also beset with major palaeobiologic, palaeoclimatic and palaeoceanographic inconsistencies (Farouk et al, 2021). Several palaeo-latitudinal-driven discrepancies have been documented, leading to major differences in the stratigraphic ranges of planktic foraminiferal bioevents, such as the endemism of marker taxa, diachronism, absence of index species due to preservational issues, and the use of varied biostratigraphic and taxonomic approaches (Bazeen et al, 2021;Coccioni & Premoli-Silva, 2015;Farouk, 2014;Gardin et al, 2012;Hewaidy et al, 2019;Huber et al, 2008;Li & Keller, 1998a;Pérez-rodríguez et al, 2012;Robaszynski & Caron, 1995;Voigt et al, 2012;Wendler, 2013).…”

Early Diagenesis in the Lacustrine Ostracods from the Songliao Basin 91.35 Million Years Ago and Its Geological Implications

“…Long-time scale and high-precision δ 13 Ccarb data play an important role in the stratigraphic correlation, paleoenvironment reconstruction, and deep-time carbon cycle modeling. For example, due to the δ 13 Ccarb of benthic foraminiferal and the micro-plankton criteria, the Abiod Formation of north-central Tunisia is restricted to the Late Campanian age, and the Campanian/Maastrichtian boundary is placed within the lowermost part of the El Haria Formation [10]. A highresolution, benthic foraminiferal δ 13 Ccarb curve from the northwest Pacific ODP Site 1209 spanning 44 to 56 million years ago (Ma) with five thousand years (kyr) resolution, presents several excursions corresponding in timing and magnitude to hyperthermal layers previously described elsewhere [11].…”