Ordovician Period, 505-438 million years ago

Ordovician Period by Josef Moravec. Ordovician picture in 14" x 11" frame, double matted in glass.

Ordovician period is the second of the six (seven in North America) periods of the Paleozoic era, and covers the time between 505 to 438 million years ago. It follows the Cambrian period and is followed by the Silurian period. The Ordovician period started at a major extinction event called the Cambrian-Ordovician extinction events some time about 488.3 million years ago and lasted for about 44.6 million years. It ended with another major extinction event about 443.7 million years ago that wiped out 60% of marine genera. A. Melott et al. (ref. 2006) suggested a ten-second gamma ray burst could have destroyed the ozone layer and exposed terrestrial and marine surface-dwelling life to deadly radiation, but most scientists agree that extinction events are complex with multiple causes.

Watermarks and Copyright markings do not appear on the final photo quality prints.