Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone

Liao, Shi Yong ; Huyskens, Magdalena H. ; Yin, Qing Zhu and Schmitz, Birger LU (2020) In Earth and Planetary Science Letters 547.
Abstract

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... (More)

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.

(Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
asteroid breakup, L-chondrite parent body, Ordovician limestone, U–Pb geochronology, zircon
in
Earth and Planetary Science Letters
volume
547
article number
116442
publisher
Elsevier
external identifiers
  • scopus:85087780337
ISSN
0012-821X
DOI
10.1016/j.epsl.2020.116442
language
English
LU publication?
yes
id
5a35e3cd-ac3a-4a92-b7d7-ddd047255e6c
date added to LUP
2020-07-21 13:26:13
date last changed
2022-04-18 23:36:23
@article{5a35e3cd-ac3a-4a92-b7d7-ddd047255e6c,
  abstract     = {{<p>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 <sup>3</sup>He profiles that pinpoint the arrival on Earth of the first dust from the breakup, and sedimentation rates constrained by cosmogenic <sup>21</sup>Ne 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.</p>}},
  author       = {{Liao, Shi Yong and Huyskens, Magdalena H. and Yin, Qing Zhu and Schmitz, Birger}},
  issn         = {{0012-821X}},
  keywords     = {{asteroid breakup; L-chondrite parent body; Ordovician limestone; U–Pb geochronology; zircon}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Earth and Planetary Science Letters}},
  title        = {{Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone}},
  url          = {{http://dx.doi.org/10.1016/j.epsl.2020.116442}},
  doi          = {{10.1016/j.epsl.2020.116442}},
  volume       = {{547}},
  year         = {{2020}},
}