(Appendix A) Nannofossil stratigraphic range chart for the late Maastrichtian section of DSDP Hole 86-577A

DOI

The response of calcareous nannofossils to the end-Cretaceous warming is investigated in the Tropical Pacific DSDP Site 577A (Shatsky Rise) through the record of species richness, Shannon diversity, distribution patterns and statistical treatments. This event is marked by a strong acme of the tropical species Micula murus and is accompanied by a decrease of Placozygus spiralis, the disappearance of Biscutum constans and a decrease in bulk d13C, indicative of a decrease in primary productivity. An increase in abundance of other Micula species at Site 577A and a drop in species richness recorded in all sites of Shatsky Rise, suggest stressed environmental conditions coincident with the end-Cretaceous warming. The acme of M. murus at Shatsky Rise and in the Atlantic Ocean is recorded within magnetochron C29r and correlates (1) with the intense warming as expressed in intermediate waters through the ?18O of benthic foraminifera, and in surface waters through poleward migration, reduced diversity and dwarfism in planktonic foraminifer assemblages, (2) with a sharp decline in marine 187Os/188Os, chemical marker of Deccan volcanic activity, and (3) with a rise in the atmospheric pCO2 record of terrestrial plants in Texas, USA, probably triggered by Deccan volcanic degassing. However, a drop of calcareous nannofossil cool-water taxa in the Equatorial and South Atlantic, as well as a first rise in abundance of M. murus in the South Atlantic and Tropical Pacific occur in the topmost part of chron C30n, and correlates with the rise in palaeotemperature record of terrestrial plants in North Dakota, USA. This suggests that initiation of the warming in the atmosphere and surface waters may predate the striking warming of intermediate water masses by 150/200 kyr. The coincidence and the links between climate change, volcanism, geochemical and biotic events at the end of the Maastrichtian thus remain to be fully elucidated.

Sediment depth is given in mbsf. # refers to specimens not included during the counting for relative abundances but documented for species richness thereafter. #3 = common (1-2 specimens per field of view [FOV]), #2= few (1 specimen per 2-10 FOV), #1 = rare (1 specimen per 11-100 FOV).

Supplement to: Thibault, Nicolas; Gardin, Silvia (2010): The calcareous nannofossil response to the end-Cretaceous warm event in the Tropical Pacific. Palaeogeography, Palaeoclimatology, Palaeoecology, 291(3-4), 239-252

Identifier
DOI https://doi.org/10.1594/PANGAEA.777821
Related Identifier IsSupplementTo https://doi.org/10.1016/j.palaeo.2010.02.036
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.777821
Provenance
Creator Thibault, Nicolas ORCID logo; Gardin, Silvia
Publisher PANGAEA
Publication Year 2010
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 1925 data points
Discipline Earth System Research
Spatial Coverage (157.723 LON, 32.442 LAT); North Pacific Ocean