Earth:Ordovician meteor event

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Short description: Event of around 467 million years ago
Paleogeography of Earth around the time of Ordovician meteor event (465 Ma)

The Ordovician meteor event was a dramatic increase in the rate at which L chondrite meteorites fell to Earth during the Middle Ordovician period, about 467.5±0.28 million years ago,[1][2] lasting for about 40 million years.[3] This rate increase is indicated by abundant fossil L chondrite meteorites in a quarry in Sweden and enhanced concentrations of ordinary chondritic chromite grains in sedimentary rocks from this time.[1][4][5][6][7]

According to a 2019 study, this temporary increase in the impact rate could have been caused by the destruction of the L chondrite parent body that was 150 kilometers (93 mi) in diameter and orbited in the asteroid belt between Mars and Jupiter.[8] This occurred around 468±0.3 million years ago, having scattered fragments into Earth-crossing orbits, a chronology which is also supported by shock ages in numerous L chondrite meteorites that fall to Earth today.[9]

It has been speculated that this influx contributed to, or possibly even instigated, the Great Ordovician Biodiversification Event, although this has been questioned.[1][2][9][10]

A 2024 study found that all of 21 studied craters from this event were at the time within 30° of the equator. Impactors directly from the asteroid belt would be expected to produce a random distribution of craters, so this suggests that the event may have been caused by an asteroid that passed within Earth's Roche limit and broke up into a ring system, material from which then deorbited and formed the craters. It is also speculated that the shading of Earth by this ring may have contributed to the Hirnantian glaciation.[3]

Possible craters

Ordovician meteor event is located in Earth
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Locations of possible craters related to the event

See also

References

  1. ↑ 1.0 1.1 1.2 Korochantseva, Ekaterina; Trieloff, Mario; Lorenz, Cyrill; Buykin, Alexey; Ivanova, Marina; Schwarz, Winfried; Hopp, Jens; Jessberger, Elmar (2007). "L-chondrite asteroid breakup tied to Ordovician meteorite shower by multiple isochron 40 Ar- 39 Ar dating". Meteoritics & Planetary Science 42 (1): 113–130. doi:10.1111/j.1945-5100.2007.tb00221.x. Bibcode: 2007M&PS...42..113K. 
  2. ↑ 2.0 2.1 Lindskog, A.; Costa, M. M.; Rasmussen, C.M.Ø.; Connelly, J. N.; Eriksson, M. E. (2017-01-24). "Refined Ordovician timescale reveals no link between asteroid breakup and biodiversification" (in En). Nature Communications 8. doi:10.1038/ncomms14066. ISSN 2041-1723. PMID 28117834. Bibcode: 2017NatCo...814066L. "It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated". 
  3. ↑ 3.0 3.1 Tomkins, Andrew G.; Martin, Erin L.; Cawood, Peter A. (November 2024). "Evidence suggesting that earth had a ring in the Ordovician". Earth and Planetary Science Letters 646. doi:10.1016/j.epsl.2024.118991. 
  4. ↑ H. Haack et al. Meteorite, asteroidal, and theoretical constraints on the 500-Ma disruption of the L chondrite parent body, Icarus, Vol. 119, p. 182 (1996).
  5. ↑ Heck, Philipp; Birger Schmitz; Heinrich Baur; Alex N. Halliday; Rainer Wieler (15 July 2004). "Fast delivery of meteorites to Earth after a major asteroid collision". Nature 430 (6997): 323–325. doi:10.1038/nature02736. PMID 15254530. Bibcode: 2004Natur.430..323H. 
  6. ↑ LINDSKOG, Anders; SCHMITZ, Birger; CRONHOLM, Anders; DRONOV, Andrei (2012-07-30). "A Russian record of a Middle Ordovician meteorite shower: Extraterrestrial chromite at Lynna River, St. Petersburg region" (in en). Meteoritics & Planetary Science 47 (8): 1274–1290. doi:10.1111/j.1945-5100.2012.01383.x. ISSN 1086-9379. Bibcode: 2012M&PS...47.1274L. 
  7. ↑ Cronholm, Anders; Schmitz, Birger (2010-07-01). "Extraterrestrial chromite distribution across the mid-Ordovician Puxi River section, central China: Evidence for a global major spike in flux of L-chondritic matter" (in en). Icarus 208 (1): 36–48. doi:10.1016/j.icarus.2010.02.004. ISSN 0019-1035. Bibcode: 2010Icar..208...36C. 
  8. ↑ Nature, Research Communities by Springer (2019-10-22). "Gigantic asteroid collision in the Ordovician period boosted biodiversity on Earth" (in en). https://communities.springernature.com/posts/gigantic-asteroid-collision-in-the-ordovician-period-boosted-biodiversity-on-earth. 
  9. ↑ 9.0 9.1 Schmitz, Birger et al. (16 December 2007). "Asteroid breakup linked to the Great Ordovician Biodiversification Event". Nature Geoscience 1: 49–53. doi:10.1038/ngeo.2007.37. http://darchive.mblwhoilibrary.org/bitstream/1912/2272/1/Naturegeosciences.pdf. 
  10. ↑ An extraterrestrial trigger for the mid-Ordovician ice age: Dust from the breakup of the L-chondrite parent body, Birger Schmitz et al, AAAS Science Advances, 18 Sep 2019: Vol. 5, no. 9, eaax4184; DOI: 10.1126/sciadv.aax4184, accessed 2019-10-09



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