Late Ordovician global warming—The Boda event

There is substantial evidence for mid-Ashgillian global warming before the latest Ordovician Hirnantian glaciation, as shown by the movement of previously lower latitude benthic faunas such as trilobites and brachiopods to progressively higher latitudes and by an increase in endemic faunas at low latitudes. This is shown by faunal dynamics on several paleocontinents and endorsed by published evidence of warmer-water sediments from Gondwana and elsewhere. We term this global warming the Boda event.