Benthic foraminiferal abundances at the Cretaceous/Paleogene boundary of ODP Hole 117-1049C at Blake Nose, Northwest Atlantic (Appendix A)

Laia Alegret; Ellen Thomas

doi:10.1594/pangaea.695112

Benthic foraminiferal abundances at the Cretaceous/Paleogene boundary of ODP Hole 117-1049C at Blake Nose, Northwest Atlantic (Appendix A)

Citation

Alegret L, Thomas E (2004). Benthic foraminiferal abundances at the Cretaceous/Paleogene boundary of ODP Hole 117-1049C at Blake Nose, Northwest Atlantic (Appendix A). PANGAEA - Publishing Network for Geoscientific and Environmental Data. Occurrence dataset https://doi.org/10.1594/pangaea.695112 accessed via GBIF.org on 2022-09-27.

Description

Sediments recovered at lower bathyal ODP Site 1049 on Blake Nose (Northwestern Atlantic) offer an opportunity to study environmental changes at the Cretaceous/Paleogene (K/P) boundary relatively close to the Chicxulub impact structure on the Yucatan peninsula, Mexico. In Hole 1049C, the boundary is located at the base of a 9-cm-thick layer with abundant spherules, considered to be impact ejecta. Uppermost Maastrichtian oozes below, and lowermost Danian pelagic oozes above the spherulebed contain well-preserved bathyal benthic foraminifera. The spherule-bed itself, in contrast, contains a mixture of shallow (neritic) and deeper (bathyal) species, and specimens vary strongly in preservation. This assemblage was probably formed by reworking and down-slope transport triggered by the K/P impact. Across the spherule-bed (i.e., the K/P boundary) only ~7% of benthic foraminiferal species became extinct, similar to the low extinction rates of benthic foraminifera worldwide. Quantitative analysis of benthic foraminiferal assemblages and morphogroups in the >63-µm size fraction indicates a relatively eutrophic, stable environment during the latest Maastrichtian, interrupted by a sudden decrease in the food supply to the benthos at the K/P boundary and a decrease in diversity of the faunas, followed by a stepped recovery during the earliest Danian. The recovery was probably linked to the gradual recovery of surface-dwelling primary producers.

Taxonomic Coverages

Chromista
rank: kingdom

Geographic Coverages

Event: 171-1049C, Blake Nose, North Atlantic Ocean ;

Bibliographic Citations

Contacts

Laia Alegret
originator

Ellen Thomas
originator

metadata author
PANGAEA - Data Publisher for Earth & Environmental Science
email: info@pangaea.de
homepage: https://www.pangaea.de

administrative point of contact
PANGAEA - Data Publisher for Earth & Environmental Science
email: info@pangaea.de
homepage: http://www.pangaea.de