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  • Bralower, TimothyPennsylvania State University (författare)

Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact

  • Artikel/kapitelEngelska2020

Förlag, utgivningsår, omfång ...

  • Amsterdam :Elsevier,2020
  • electronicrdacarrier

Nummerbeteckningar

  • LIBRIS-ID:oai:DiVA.org:nrm-4111
  • https://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-4111URI
  • https://doi.org/10.1016/j.epsl.2020.116476DOI

Kompletterande språkuppgifter

  • Språk:engelska
  • Sammanfattning på:engelska

Ingår i deldatabas

Klassifikation

  • Ämneskategori:ref swepub-contenttype
  • Ämneskategori:art swepub-publicationtype

Anmärkningar

  • 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.

Ämnesord och genrebeteckningar

Biuppslag (personer, institutioner, konferenser, titlar ...)

  • Cosmidis, JuliePennsylvania State University (författare)
  • Heaney, PeterPennsylvania State University (författare)
  • Kump, LeePennsylvania State University (författare)
  • Morgan, JoannaImperial College London (författare)
  • Haroer, DustinUniversity of Kansas (författare)
  • Lyons, ShelbyPennsylvania State University (författare)
  • Freeman, KatherinePennsylvania State University (författare)
  • Grice, KlitiCurtin University (författare)
  • Wendler, JensFriedrich-Schiller-University Jena (författare)
  • Zachos, JamesUniversity of California Santa Cruz (författare)
  • Artemieva, NataliaPlanetary Science Institute, Tucson (författare)
  • Chen, Si AthenaPennsylvania State University (författare)
  • Gulick, SeanUniversity of Texas (författare)
  • House, ChristopherPennsylvania State University (författare)
  • Jones, HeatherPennsylvania State University (författare)
  • Lowery, ChristopherUniversity of Texas at Austin (författare)
  • Nims, ChristinePennsylvania State University (författare)
  • Schaefer, BettinaCurtin University (författare)
  • Thomas, EllenYale University (författare)
  • Vajda, ViviNaturhistoriska riksmuseet,Enheten för paleobiologi,Department of Geology, Lund University, Sweden(Swepub:nrm)vivivajd (författare)
  • Pennsylvania State UniversityImperial College London (creator_code:org_t)

Sammanhörande titlar

  • Ingår i:Earth and Planetary Science LettersAmsterdam : Elsevier5480012-821X1385-013X

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