Devonian landscape with club moss and bacteria mats

Devonian period

The Devonian is also known as the Age of Fishes, since several major fish lineages evolved at this time. Sea levels were high and the global climate was warm. Sea surface temperatures in the tropics averaged 30 Celsius, much like the warmer parts of the Pacific today. Growth rings from corals living during the Devonian period have provided evidence that there were more than 365 days in the year back then - about 404 at the start of the period, falling to 396 by the end.

Began: 417 million years ago

Ended: Late Devonian mass extinction
354 million years ago

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What the Earth was like

A map of the Earth in the Devonian Period

Reconstruction of the Earth in the Devonian period, 417 million - 354 million years ago. Credit: Dr Ron Blakey, NAU Geology.

Causes of extinctions

During this period the following events are thought to have contributed to the Late Devonian mass extinction.

Flood basalt eruptions Flood basalt eruptions
Flood basalt eruptions are a type of large-scale volcanic activity, both in terms of extent and duration, that can occur on land or on the ocean floor. A flood basalt may continue to erupt for tens of thousands - possibly millions - of years and the lava can cover hundreds of thousands of kilometres.
Impact events Impact events
Impact events, proposed as causes of mass extinction, are when the planet is struck by a comet or meteor large enough to create a huge shockwave felt around the globe. Widespread dust and debris rain down, disrupting the climate and causing extinction on a global, rather than local, scale.

Types of fossils formed in this period