DOI: 10.1016/j.epsl.2020.116442
论文题名: Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone
作者: Liao S. ; Huyskens M.H. ; Yin Q.-Z. ; Schmitz B.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 547 语种: 英语
中文关键词: 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165114
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
Liao S.,Huyskens M.H.,Yin Q.-Z.,et al. Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone[J]. Earth and Planetary Science Letters,2020-01-01,547