Life on the sea floor during the Cambrian period

Cambrian period

The Cambrian is famed for its explosion of abundant and diverse life forms. Life had diversified into many forms and many ways of living: animals now swam, crawled, burrowed, hunted, defended themselves and hid away. Some creatures had evolved hard parts such as shells, which readily fossilised and left a clear record behind. However, sometimes geologists get lucky and find beautiful fossils of soft and squishy creatures - as at the Burgess Shale site. In Cambrian times there was no life on land and little or none in freshwater - the sea was still very much the centre of living activity.

Began: 545 million years ago

Ended: 495 million years ago

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What the Earth was like

A map of the Earth in the Cambrian Period

Reconstruction of the Earth in the Cambrian period, 545 million - 495 million years ago. Credit: Dr Ron Blakey, NAU Geology.

Causes of extinctions

During this period the following extinction level events are thought to have occurred.

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.

Types of fossils formed in this period

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