Known as the Great Oxygenation Event, the effects were actually quite dramatic including killing most life on earth and triggering a 300 million year ice age as

Known as the Great Oxygenation Event, the effects were actually quite dramatic including killing most life on earth and triggering a 300 million year ice age as well as creating most of the world's iron deposits. http://en.m.wikipedia.org/wiki/Great_Oxygenation_Event http://en.m.wikipedia.org/wiki/Great_Oxygenation_Event