Benthic foraminifera across the Cretaceous/Paleogene boundary in the Southern Ocean (ODP Site 690): Diversity, food and carbonate saturation

摘要: Abstract The impact of an asteroid at the Cretaceous/Paleogene (K/Pg) boundary triggered dramatic biotic, biogeochemical and sedimentological changes in oceans that have been intensively studied. Paleo-biogeographical differences biotic response to its environmental consequences, however, less well documented. We present a high-resolution analysis benthic foraminiferal assemblages Southern Ocean ODP Site 690 (Maud Rise, Weddell Sea, Antarctica). At this high latitude site, late Maastrichtian variability was high, but were not diverse than lower latitudes, contrast those planktic calcifiers. Also calcifiers, foraminifera did suffer significant extinction K/Pg boundary, show transient assemblage decreased diversity. 690, rate even (~ 3%) other sites. accumulation varied little across indicating food supply sea floor affected lesser extent Compared assemblages, Danian diversity greater relative abundance heavily calcified taxa such as Stensioeina beccariiformis Paralabamina lunata. This change could reflect post-extinction proliferation different photosynthesizers (thus for benthos) dominant during Late Cretaceous, therefore nature rather amount organic matter supplied seafloor. However, severe pelagic calcifiers caused carbonate supersaturation oceans, thus might given competitive advantage species with large, tests. indirect effect may influenced deep-sea dwellers, documenting complexity effects major disturbance.