Like stromatolites, these other microbial mats hold minerals and sand particles in their matrix, preventing erosion of the land around them. After they die, the sand eventually turns to sandstone and preserves the mats as fossils.
Noffke and her team looked in Western Australia's Pilbara region for the community of fossil organisms turned to stone. Their discovery still needs additional scrutiny to confirm the age, but their study illustrates how diverse life was just a billion years after the planet formed.
As the Washington Post reported:
"It's not just finding this stuff that's interesting," says Alan Decho, a geobiologist at the University of South Carolina's Arnold School of Public Health. "It's showing that the life had some organization to it." Ridges that crisscross the rocks like strands in a spider web hint that primitive bacteria linked up in sprawling networks. Like their modern counterparts, they may have lived in the equivalent of microbial cities that hosted thousands of kinds of bacteria, each specialized for a different task and communicating with the others via chemical signals.