Frasnian

The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from 382.31 million years ago to 372.15 million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage.

Major reef-building was under way during the Frasnian Stage, particularly in western Canada and Australia. On land, the first forests were taking shape. In North America, the Antler orogeny peaked, which were contemporary with the Bretonic phase of the Variscan orogeny in Europe.

The Frasnian coincides with the second half of the "charcoal gap" in the fossil record, a time when atmospheric oxygen levels were below 13 percent, the minimum necessary to sustain wildfires.

Name and definition

The Frasnian Stage was proposed in 1879 by French geologist Jules Gosselet. It became an official part of the Upper Devonian in 1981. The stage is named after the village of Frasnes-lez-Couvin in Belgium.