Calcareous plankton stratigraphy around the Pliocene “Eltanin” asteroid impact area (SE Pacific): documentation and application for geological and paleoceanographic reconstruction

Conventional qualitative and semi quantitative analyses of calcareous nannofossils and planktic foraminifers from four cores (PS2704-1, PS2708-1, PS2709-1, E13-4) documenting the area of the Eltanin impact into the Bellingshausen Sea were done to (a) identify sediment disturbances and reworking, (b) constrain the stratigraphic framework of the impact-related sediment sequences, and (c) evaluate probable environmental consequences of the impact. The calcareous microfossil stratigraphy from the autochthonous sediments above and below the impact-related sediments places the impact event into the late Pliocene at around 2.15 Ma, and indicates that sediments as old as middle Eocene were disturbed by the impact. The qualitative and quantitative determination of displaced calcareous microfossils allows the reconstruction of sediment disturbances, displacement, and resettlement related to the impact event. No signs for significant changes in the assemblages produced and sedimented after the impact could be observed, indicating that the impact had no major influence on regional or global climate conditions that can be detected in the geological record.