# Cambrian–Ordovician extinction event

> mass extinction event; occurred approximately 488 million years ago

**Wikidata**: [Q1050953](https://www.wikidata.org/wiki/Q1050953)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Cambrian–Ordovician_extinction_event)  
**Source**: https://4ort.xyz/entity/cambrian-ordovician-extinction-event


## References

1. [Source](http://stratigraphy.org/ICSchart/ChronostratChart2018-08.pdf)
2. Freebase Data Dumps. 2013