Environment

Oldest Evidence for Life on Land Unearthed in South Africa

About 3.22 billion years ago, slimy layers of microbes coated pebbles in what was perhaps an ancient riverbed. Those ancient microbial mats, preserved for eons and only recently discovered in South Africa, may be the oldest fossil evidence of life on land, according to a new study.

The ancient evidence of terrestrial life is about a half billion years older than the previous record holder — fossilized remains of microbes found decades ago in South Africa and Australia, said Stefan Lalonde, a geochemist from the European Institute for Marine Studies in France and a co-author of the new study, published July 23 in the journal Nature Geoscience.

Geological evidence has hinted that life existed in the oceans as far back as 3.8 billion years ago. But signs of terrestrial life have been rarer — possibly because most of the planet might have been under water until 3 billion years ago.