Cretaceous planktonic foraminiferal biostratigraphy of the Umbria–Marche Basin (central Italy)

Abstract

The Umbria-Marche Basin of central Italy includes some of the most studied, continuous and well-exposed sequences of Cretaceous pelagic sediments known from the Tethyan Realm. A complete and well-preserved Cretaceous pelagic composite succession (CPCS) of this area is here presented. It has been constructed through the integration of the well-established magnetostratigraphy with the planktonic foraminiferal biostratigraphy based on previous and newly identified events from six key sections and one drill core. The recovery of planktonic foraminifera successfully disaggregated from the hard lithologies allows the identification and precise placement of several primary and secondary bioevents. In particular, the record of the identified bioevents counts thirty-five primary biohorizons, which allow the subdivision of the studied succession into thirty-four zones and four subzones. Following this study and previous findings on Cretaceous planktonic foraminifera, an updated planktonic foraminiferal zonation for the Cretaceous Period is proposed. This refined magnetobiostratigraphic framework, which in this study is integrated with the Cretaceous inoceramid, anoxic, and carbon-isotope events recognized in the Umbria-Marche Basin, may provide an invaluable tool for improving Cretaceous correlations at low to middle latitudes, as well as palaeoenvironmental, palaeoclimatic and palaeoceanographic interpretations.