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DOI	10.1016/j.epsl.2020.116442
	Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone
	Liao S.; Huyskens M.H.; Yin Q.-Z.; Schmitz B.
发表日期	2020
ISSN	0012821X
卷号	547
英文摘要	The breakup of the L-chondrite parent body (LCPB) in the mid-Ordovician is the largest documented asteroid breakup event during the past 3 Gyr. It affected Earth by a dramatic increase in the flux of L-chondritic material and left prominent traces in both meteorite and sedimentary records. A precise constraint on the timing of the LCPB breakup is important when evaluating the terrestrial biotic and climatic effects of the event, as well as for global stratigraphic correlations. Direct dating using heavily shocked L chondrites is hampered by both incomplete initial K-Ar degassing and isotopic resetting by later impact events. In order to better constrain the absolute age of this event we carried out high-precision U–Pb dating of zircons from three limestone beds recording discrete volcanic ash fallouts within mid-Ordovician strata in southern Sweden. These strata are rich in fossilized L-chondritic meteorites (1-20 cm large) that arrived on Earth shortly after the breakup event. Zircons from the ash-bearing layers provide stratigraphically consistent depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. Combined with recently published 3He profiles that pinpoint the arrival on Earth of the first dust from the breakup, and sedimentation rates constrained by cosmogenic 21Ne in the fossil meteorites, the LCPB breakup is estimated to have occurred at 465.76 ± 0.30 Ma. This provides the presently most precise absolute dating of the LCPB breakup, enabling a robust global stratigraphic correlation of bounding strata. Based on our new U–Pb data for the ash-bearing beds, the absolute ages for the boundaries of biozones and Dapingian–Floian stages overlap within error with those given by the 2012 Geological Timescale and require no modification. © 2020 Elsevier B.V.
关键词	asteroid breakup L-chondrite parent body Ordovician limestone U–Pb geochronology zircon
英文关键词	Geochronology; Lime; Limestone; Meteorites; Silicate minerals; Stratigraphy; Volcanoes; Zircon; Bearing layers; Chondritic meteorites; Climatic effects; High-precision; Sedimentary records; Sedimentation rates; Stratigraphic correlation; Volcanic ash fallout; Potassium compounds; chondrite; geochronology; limestone; Ordovician; parent body; precision; stratigraphic correlation; timescale; uranium-lead dating; zircon; Sweden
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/202736
作者单位	Astrogeobiology Laboratory, Department of Physics, Lund University, Lund, Sweden; Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China; CAS Center for Excellence in Comparative Planetology, Hefei, China; Department of Earth and Planetary Sciences, University of California, Davis, CA 95616, United States
推荐引用方式 GB/T 7714	Liao S.,Huyskens M.H.,Yin Q.-Z.,等. Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone[J],2020,547.
APA	Liao S.,Huyskens M.H.,Yin Q.-Z.,&Schmitz B..(2020).Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone.Earth and Planetary Science Letters,547.
MLA	Liao S.,et al."Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone".Earth and Planetary Science Letters 547(2020).