Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact
Pennsylvania State University.
Pennsylvania State University.
Pennsylvania State University.
Pennsylvania State University.
Show others and affiliations
2020 (English)In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 548, article id 116476Article in journal (Refereed) Published
Abstract [en]

Microcrystalline calcite (micrite) dominates the sedimentary record of the aftermath of the Cretaceous–Paleogene (K–Pg) impact at 31 sites globally, with records ranging from the deep ocean to the Chicxulub impact crater, over intervals ranging from a few centimeters to more than seventeen meters. This micrite-rich layer provides important information about the chemistry and biology of the oceans after the impact. Detailed high-resolution scanning electron microscopy demonstrates that the layer contains abundant calcite crystals in the micron size range with a variety of forms. Crystals are often constructed of delicate, oriented agglomerates of sub-micrometer mesocrystals indicative of rapid precipitation. We compare the form of crystals with natural and experimental calcite to shed light on their origin. Close to the crater, a significant part of the micrite may derive from the initial backreaction of CaO vaporized during impact. In more distal sites, simple interlocking rhombohedral crystals resemble calcite precipitated from solution. Globally, we found unique calcite crystals associated with fossilized extracellular materials that strikingly resemble calcite precipitated by various types of bacteria in natural and laboratory settings. The micrite-rich layer contains abundant bacterial and eukaryotic algal biomarkers and most likely represents global microbial blooms initiated within millennia of the K–Pg mass extinction. Cyanobacteria and non-haptophyte microalgae likely proliferated as dominant primary producers in cold immediate post-impact environments. As surface-water saturation state rose over the following millennia due to the loss of eukaryotic carbonate producers and continuing river input of alkalinity, “whitings” induced by cyanobacteria replaced calcareous nannoplankton as major carbonate producers. We postulate that the blooms grew in supersaturated surface waters as evidenced by crystals that resemble calcite precipitates from solution. The microbial biomass may have served as a food source enabling survival of a portion of the marine biota, ultimately including life on the deep seafloor. Although the dominance of cyanobacterial and algal photosynthesis would have weakened the biological pump, it still would have removed sufficient nutrients from surface waters thus conditioning the ocean for the recovery of biota at highertrophic levels.

Place, publisher, year, edition, pages
Amsterdam: Elsevier, 2020. Vol. 548, article id 116476
Keywords [en]
K-Pg boundary, micrite, cyanobacterial bloom, Chicxulub
National Category
Other Earth and Related Environmental Sciences
Research subject
The changing Earth
Identifiers
URN: urn:nbn:se:nrm:diva-4111DOI: 10.1016/j.epsl.2020.116476OAI: oai:DiVA.org:nrm-4111DiVA, id: diva2:1511605
Funder
Swedish Research Council, 2019-04061Available from: 2020-12-18 Created: 2020-12-18 Last updated: 2020-12-18Bibliographically approved

Open Access in DiVA

fulltext(4216 kB)467 downloads
File information
File name FULLTEXT01.pdfFile size 4216 kBChecksum SHA-512
7f22bbe305640aedae598baad9e1fa50d3ee41baae7ee9b23d8c8e06c088a665916765ea8e74fd0ab88801f85fec019417b257b70190b55ec1f8793679d66554
Type fulltextMimetype application/pdf

Other links

Publisher's full texthttps://doi.org/10.1016/j.epsl.2020.116476

Search in DiVA

By author/editor
Vajda, Vivi
By organisation
Department of Paleobiology
In the same journal
Earth and Planetary Science Letters
Other Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 467 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 751 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf