Ordovician meteor event

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Paleogeography of the Middle Ordovician (~470 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] This 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][3][4][5][6] This temporary increase in the impact rate was most likely caused by the destruction of the L-chondrite parent body 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.[7] It has been strongly[8] hypothesized that this influx contributed to, or possibly even instigated, the Great Ordovician Biodiversification Event, although this had been previously questioned.[1][7][2]

Possible craters[edit]

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

Formerly estimated to be Ordovician, revised to Cambrian (~535 Ma)
Turquoise pog.svg Neugrund crater

See also[edit]

References[edit]

  1. ^ a b c 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.
  2. ^ a b 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". Nature Communications. 8: 14066. doi:10.1038/ncomms14066. ISSN 2041-1723. PMC 5286199. PMID 28117834. 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. ^ 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).
  4. ^ 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. Bibcode:2004Natur.430..323H. doi:10.1038/nature02736. PMID 15254530.
  5. ^ 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". Meteoritics & Planetary Science. 47 (8): 1274–1290. doi:10.1111/j.1945-5100.2012.01383.x. ISSN 1086-9379.
  6. ^ 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". Icarus. 208 (1): 36–48. doi:10.1016/j.icarus.2010.02.004. ISSN 0019-1035.
  7. ^ a b Schmitz, Birger; Harper, David; et al. (16 December 2007). "Asteroid breakup linked to the Great Ordovician Biodiversification Event" (PDF). Nature Geoscience. 1: 49–53. doi:10.1038/ngeo.2007.37. hdl:1912/2272.
  8. ^ 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