Benthic foraminiferal survival through the early Paleocene (Danian) greenhouse climate interval based on analysis of IODP Site U1457 (Laxmi Basin, Northern Indian Ocean)

Abstract

The early Paleocene (Danian) period included three major events: the Cretaceous-Paleogene (K-Pg) extinction at 66.0 ​Ma, the Dan-C2 hyperthermal at 65.2 ​Ma, and the latest Danian hyperthermal at ∼62.2 ​Ma. In this paper, we investigate benthic foraminiferal diversity patterns, morphotypes, and oxygen conditions along with the carbonates and magnetic susceptibility records at IODP Site U1457 (Laxmi Basin, Northern Indian Ocean) to understand the effects of these Danian events on the marine community in the Indian Ocean. Findings suggest that foraminifera persisted across these major events. Species belonging to Bolivina, Glandulina, Hoeglundina, Parrelloides and Quadrimorphina genus were dominant above the K-Pg boundary whereas Bolivina, Bulimina, Cassidulina, Cornuspira, Gyroidinoides, Melonis, Oolina, Pullenia, Reussoolina and Rutherfordoides dominated across subsequent hyperthermal events. We calculated the average oxygen content at 0.16 ​ml/L in accordance with oxyphilic species abundance, which shows that the Laxmi Basin comprised, mostly, a suboxic to dysoxic environment. The benthic foraminiferal diversity patterns, primary anomalies of calcium carbonates, and magnetic susceptibility, integrated with previously-published global datasets of carbon and oxygen isotopes, help to define the major geologic events at the study site and show how biotas responded to global change during the early Paleocene greenhouse mode.