Calcareous nannofossil biostratigraphy of Late Campanian–Early Maastrichtian sediments in southwest Iran

Calcareous nannofossil biostratigraphic analysis was carried out for the Upper Campanian–Lower Maastrichtian sediments of the Gurpi anticline in the Zagros Basin in southwest Iran. Calcareous nannofossil assemblages are abundant and well preserved allowing getting a precise bioevent sequence. The lower part of the Gurpi Formation at the studied section is assigned to the Late Campanian/Early Maastrichtian and is spanning from the middle part of CC22/UC15eTP to CC24/UC18. Eight bioevents are recorded at the studied interval. Comparison of these biohorizons with those in the Gubbio area in Italy and Tercis les Bains in France as the Global Stratotype Section and Point (GSSP) for the Campanian–Maastrichtian boundary (CMB) indicate some diachroneity between the Gurpi Formation in the Zagros Basin (part of the Neo–Tethys) and the mentioned sections.