Life on Land 100M Years Older Than Previously Thought

New research pushes back the date of the Great Oxidization Event to 2.48 billion years ago.

A team of international researchers conclude that life on land began some 2.48 billion years ago, 100 million years earlier than was widely believed before. The team declares in a new study published in Nature that that's when the Great Oxidization Event occurred, a time when oxygen was released into the Earth's atmosphere in huge quantities, making life on the planet more sustainable. To find out the date, the team, which included Canadians, Americans, Brazilians, French, and Australians, studied the amount of the element chromium found in ancient sea beds. Chromium is released when a bacteria that breathes oxygen breaks down the mineral pyrite. Hence, the older the chromium, the longer ago that tiny microbes began living on land. Life in the oceans was first believed to have emerged around four billion years ago.