Ordovician meteor event

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. 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.

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 km in diameter and orbited between Mars and Jupiter. 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.

It has been speculated that this influx contributed to, or possibly even instigated, the Great Ordovician Biodiversification Event, although this has been questioned.