(evolutionary theory, geology) One of five historical events in which the Earth experienced a loss of ∼75% of all species over a geological interval of less than 3 million years, the most recent being the Cretaceous–Paleogene extinction event 66 million years ago.

plural of extinction level event

Synonym of Permian extinction

(evolutionary theory, geology) A volcanic mass extinction at the end of the Permian period 251.9 million years ago.

The rapid dying off of a large percentage of all animal species in a comparatively short period of time 65.5 million years ago. This coincides with the end of the Cretaceous period, and may have been caused by an impact event.

Synonym of Triassic-Jurassic extinction event.

(evolutionary theory, geology) Synonym of Permian-Triassic extinction

A mass extinction between the Triassic and Jurassic periods 201.3 million years ago.

The highest voltage where partial discharge starts to cease to occur.