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Complex life may have had a false start 2.3 billion years ago

Complex life may have had a false start 2.3 billion years ago

New Scientist

Image:  maxelman

It was a sign of things to come. About 2.3 billion years ago, our primitive planet was an oxygen-poor world profoundly different from now – but then it briefly and mysteriously gained an oxygen-rich atmosphere.

This so-called Lomagundi Event could have provided a fleeting opportunity for complex, animal-like creatures to evolve billions of years before the ancestors of all animals we know today appeared.

Earth is thought to have begun to develop its modern, oxygen-rich atmosphere as recently as 800 million years ago. This is roughly when biologically complex, oxygen-breathing animals first appear in the fossil record, leading many to suggest that animal life was made possible by the rise in atmospheric oxygen.

Before 800 million years ago, there may have been little gaseous oxygen around – one 2014 estimate suggests there may have been as little as 0.1 per cent of the present level.

The Lomagundi Event – between 2.3 and 2.1 billion years ago – is an exception to this early oxygen-poor world. Chemical analysis of “Lomagundi” rocks hints that the amount of organic carbon buried in the deep ocean suddenly spiked. Read more on…