Some of the rocks in Western Australia’s Pilbara region contain the oldest known traces of life on Earth at 3.49 billion years old.
These findings could be useful in looking for signs of life on other planets like Mars.
A U.S. research team found criss-cross patterns and textures on Pilbara sandstone, referred to as Microbially Induced Sedimentary Structures (MISS). They are thought to have been created by a varied community of bacteria between 3.8 and 2.5 billion years ago during the Archean eon.
The Pilbara was once a coastal plain with sand from which the rocks formed as the microbes built up mats. Nowadays, such mats still exist, and contain photosynthetic cyanobacteria alongside other bacteria that use the oxygen thus produced.
The researchers studied the ratio of two carbon isotopes in the sandstone, and found it matched that of organic carbon, confirming it was probably made by living organisms.
Although older rocks are known on Earth, the ones at Pilbara are more significant.
“[T]hese are the best-preserved sedimentary rocks we know of, the ones most likely to preserve the really tiny structures and chemicals that provide evidence for life,” said study co-author Maud Walsh at Louisiana State University, according to The Sydney Morning Herald.
The results were presented at the annual meeting of the Geological Society of America in November.
The Epoch Times publishes in 35 countries and in 20 languages. Subscribe to our e-newsletter.