The tiny structures -- called stromatolites -- were found in ancient rock along the edge of Greenland's ice cap, and were 220 million years older than the previous record holders.
And, he added, they offer hope that very basic life may at one point have existed on Mars.
"This discovery represents a new benchmark for the oldest preserved evidence of life on Earth ," Professor Martin Julian Van Kranendonk, a geology expert at the University of New South Wales and study co-author, said in a statement.
The one-to-four centimetre (0.4-1.6 inch) high Isua stromatolites were exposed after the melting of a snow patch in the Isua Greenstone Belt of Greenland.
Stromatolites are formed when microorganisms, such as certain kinds of bacteria, trap bits of sediment together in layers. These layers build up over time to create solid rock.