The changes in ocean chemistry were gradual. The Archaean period lasted 1.5 billion years. This is more than half of Earth’s ...

Cyanobacteria get their names from their striking blue-green colour The Great Oxygenation Event happened globally, so banded iron formations can be found on every continent. They allow scientists to ...

The "bands" of different colors in banded iron formations record this shift with an alternation between deposits of iron deposited in the absence of oxygen and red oxidized iron. The recent paper ...

This demonstrates the source of the increasing atmospheric oxygen. The banded iron formations show that, during the period of their formation, levels of atmospheric oxygen varied, producing ...

Banded iron formations were deposited in the Archean and Paleoproterozoic eons, roughly between 3.8 and 1.8 billion years ago. Life back then was confined to one-cell organisms in the oceans.