Ordovician meteor event
The Ordovician meteor event was a dramatic increase in the rate at which
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 speculated that this influx contributed to, or possibly even instigated, the Great Ordovician Biodiversification Event, although this has been questioned.[1][2][7][8]
Possible craters
See also
- Österplana 065
- Late Ordovician impact craters
References
- ^ .
- ^ 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
- ^ 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).
- S2CID 4393398.
- ISSN 1086-9379.
- ISSN 0019-1035.
- ^ hdl:1912/2272.
- ^ 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