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Sunday, November 22, 2009

Photo: Shifting Volcanoes Made Early Complex Life Possible


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A rise in oxygen levels around 2.5 billion years ago may have occurred after a massive tectonic shift forced many submerged volcanoes above water, a new study says.

These above-ground volcanoes, such as the Piton de La Fournaise volcano on the island of La Réunion (above, erupting in April 2007) stopped spewing oxygen-destroying chemicals into the air—allowing vital ingredients for complex life to build up.

Photograph by Richard Bouhet/AFP/Getty Images