The Cambrian Mass Extinction

Fast Facts

-the Cambrian period ranges from 543-510 million years ago

-the most important animal group of the Cambrian were the trilobites

-four mass extinctions occurred during the course of the Cambrian

Geological Setting

During the Cambrian period the world was largely covered by epeiric seas, and existing organisms were entirely marine. At the beginning of the period, only small skeletonized sponges and molluscs were present, but by about the middle of the Cambrian, diversification of the shelly fauna occurred. The most important phyla present in Cambrian communities included trilobites, archaeocyathids, brachiopods, molluscs, and echinoderms.

Species Affected

At least four major extinctions occurred during the Cambrian. The first extinction occurred at the Early Cambrian epoch boundary. During this event, the oldest group of trilobites, the olnellids, perished as well as the primary reef-building organisms, the archaeocyathids. The remaining three extinctions were irregularly distributed around the Late Cambrian epoch boundary, and as a whole, severly affected trilobites, brachiopods, and conodonts.

Causes of the Cambrian Mass Extinction

Mass Extinctions of the Phanerozoic Menu

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