气候变化领域集成服务门户(CCPortal): Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact

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DOI	10.1016/j.epsl.2020.116476
	Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact
	Bralower T.J.; Cosmidis J.; Heaney P.J.; Kump L.R.; Morgan J.V.; Harper D.T.; Lyons S.L.; Freeman K.H.; Grice K.; Wendler J.E.; Zachos J.C.; Artemieva N.; Chen S.A.; Gulick S.P.S.; House C.H.; Jones H.L.; Lowery C.M.; Nims C.; Schaefer B.; Thomas E.; Vajda V.
发表日期	2020
ISSN	0012821X
卷号	548
英文摘要	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 higher trophic levels. © 2020 Elsevier B.V.
关键词	Chicxulub cyanobacterial bloom K-Pg boundary micrite
英文关键词	Alkalinity; Calcite; Calcium oxide; Carbonation; Crystals; Microcrystals; Scanning electron microscopy; Calcite crystals; Cretaceous-Paleogene boundary; High-resolution scanning electron microscopies; Microbial biomass; Primary producers; Rhombohedral crystals; Sedimentary records; Water saturation state; Surface waters; algal bloom; boundary condition; carbonate; Cretaceous-Paleogene boundary; deep sea; deposition; scanning electron microscopy; algae; Bacteria (microorganisms); Cyanobacteria; Eukaryota
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202506
作者单位	Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Department of Geosciences, Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, United States; Department of Earth Science and Engineering, Imperial College, London, United Kingdom; Department of Geology, The University of Kansas, Lawrence, KS 66045, United States; WA-Organic and Isotope Geochemistry Centre, The Institute for Geoscience Research, School of Earth and Planetary Science, Curtin University, Perth, WA, Australia; Institute of Geosciences, Friedrich-Schiller-University Jena, Burgweg 11, Jena, 07749, Germany; Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States; Planetary Science Institute, Tucson, AZ, United States; Institute for Geophysics, Dept. of Geological Sciences, Jackson School of Geosciences, Center for Planetary Systems Habitability, University of Texas at Austin, Unit...
推荐引用方式 GB/T 7714	Bralower T.J.,Cosmidis J.,Heaney P.J.,et al. Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact[J],2020,548.
APA	Bralower T.J..,Cosmidis J..,Heaney P.J..,Kump L.R..,Morgan J.V..,...&Vajda V..(2020).Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact.Earth and Planetary Science Letters,548.
MLA	Bralower T.J.,et al."Origin of a global carbonate layer deposited in the aftermath of the Cretaceous-Paleogene boundary impact".Earth and Planetary Science Letters 548(2020).