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Origin of a global ...
Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact
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- Bralower, Timothy (författare)
- Pennsylvania State University
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- Cosmidis, Julie (författare)
- Pennsylvania State University
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- Heaney, Peter (författare)
- Pennsylvania State University
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- Kump, Lee (författare)
- Pennsylvania State University
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- Morgan, Joanna (författare)
- Imperial College London
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- Haroer, Dustin (författare)
- University of Kansas
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- Lyons, Shelby (författare)
- Pennsylvania State University
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- Freeman, Katherine (författare)
- Pennsylvania State University
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- Grice, Kliti (författare)
- Curtin University
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- Wendler, Jens (författare)
- Friedrich-Schiller-University Jena
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- Zachos, James (författare)
- University of California Santa Cruz
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- Artemieva, Natalia (författare)
- Planetary Science Institute, Tucson
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- Chen, Si Athena (författare)
- Pennsylvania State University
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- Gulick, Sean (författare)
- University of Texas
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- House, Christopher (författare)
- Pennsylvania State University
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- Jones, Heather (författare)
- Pennsylvania State University
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- Lowery, Christopher (författare)
- University of Texas at Austin
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- Nims, Christine (författare)
- Pennsylvania State University
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- Schaefer, Bettina (författare)
- Curtin University
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- Thomas, Ellen (författare)
- Yale University
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- Vajda, Vivi (författare)
- Naturhistoriska riksmuseet,Enheten för paleobiologi,Department of Geology, Lund University, Sweden
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(creator_code:org_t)
- Amsterdam : Elsevier, 2020
- 2020
- Engelska.
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Ingår i: Earth and Planetary Science Letters. - Amsterdam : Elsevier. - 0012-821X .- 1385-013X. ; 548
- Relaterad länk:
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https://doi.org/10.1...
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https://nrm.diva-por... (primary) (Raw object)
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- 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
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)
Nyckelord
- K-Pg boundary
- micrite
- cyanobacterial bloom
- Chicxulub
- The changing Earth
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- ref (ämneskategori)
- art (ämneskategori)
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Bralower, Timoth ...
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Cosmidis, Julie
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Heaney, Peter
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Kump, Lee
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Morgan, Joanna
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Haroer, Dustin
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visa fler...
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Lyons, Shelby
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Freeman, Katheri ...
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Grice, Kliti
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Wendler, Jens
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Zachos, James
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Artemieva, Natal ...
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Chen, Si Athena
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Gulick, Sean
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House, Christoph ...
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Jones, Heather
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Lowery, Christop ...
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Nims, Christine
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Schaefer, Bettin ...
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Thomas, Ellen
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Vajda, Vivi
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