what year did the ordovician period end
The Ordovician Period started at a major extinction event called the CambrianâOrdovician extinction events about 485.4 Â± 1.9 Mya (million years ago), and lasted for about 42 million years. It ended with the OrdovicianâSilurian extinction event, about 443.8 Â± 1.5 Mya (ICS, 2004) that wiped out 60% of marine genera.