Ordovician Extinction

The End Ordovician Extinction seems weird to paleontologists. There’s a lot of agreement on the earth cooling at the end of the Ordovician, right up to evidence of major glaciation and a harsh ice age, but there are serious suggestions for the cause of the glaciation or extinction that will boggle your mind.

Some of these serious suggestions are of extra-terrestrial origin:

Any of these events could cause glaciation, but by different mechanisms. The L-chondritic parent body break-up and resulting increased dust infall to the earth definitely happened. The gamma ray burst is more speculative.

I’m tickled that meteor impact isn’t the only astronomical event that could have had a large effect on the earth’s biosphere.

The Palaeocast episode on the Great Ordovician Biodiversity Event is definitely worth listening to, even if it only touches on the end-Ordovician extinction, and does not speculate on causes.

The Winneshiek biota were preserved in a smaller Ordovician impact structure.