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, 467.3 ± 1.6 million years ago. This is indicated by the comparatively tight age clustering of L chondrite grains in sediments in southern Sweden, and an excess of fossil L chondrite meteorites in a quarry in Sweden that represents meteorite falls arriving at a much higher rate than is typical on Earth. This temporary increase in the impact rate was most likely caused by the destruction of the L-chondrite parent body 470 ± 6 million years ago having scattered fragments into Earth-crossing orbits, a chronology which is supported by shock ages in numerous L-chondrite meteorites that continue to fall to Earth today. It is hypothesized that this influx was associated with, or possibly caused, the Great Ordovician Biodiversification Event.
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