Deep Sea Environments Across the Cretaceous/Paleogene boundary in the eastern South Atlantic Ocean

摘要: Sediments recovered at ODP Site 1262 on Walvis Ridge (eastern South Atlantic Ocean, paleodepth ∼2500–3000 m) offer an opportunity to look into the nature and cause(s) of benthic foraminiferal turnover across Cretaceous/Paleogene (K/Pg) boundary abyssal depths a location relatively remote from asteroid impact Yucatan peninsula. Late Maastrichtian assemblages were diverse heterogeneous, reflecting oligoto mesotrophic conditions sea floor. As other locations, there was no significant extinction species K/Pg boundary, but diversity heterogeneity decreased precipitously. The percentage infaunal buliminid taxa rapidly, total remained essentially unchanged. Benthic accumulation rates (BFAR) dropped itself, fluctuated strongly later in Danian. After opportunistic increased relative abundance, fluctuated. There thus is clear agreement between three proxies which have been used indicate high food supply floor: buliminids, taxa, BFAR. This discrepancy might that changed character (e.g., type food, temporal variability flux), did not show long-term, large net change amount. strong fluctuations BFAR, environmental instability started persisted through planktic zones Pα P1a. In lower zone P1b, agglutinated genera Spiroplectammina Clavulinoides, thought be indicative increasing levels supply, abundance while buliminids low. Possibly, took over least part niche Paleocene, as result rise calcium carbonate compensation depth. Towards upper studied interval (lower Subzone 1c), stabilized, with almost back values, although BFAR fully recover. © 2006 Elsevier B.V. All rights reserved.