Microscopic fossils have been discovered in a Western Australian rock that is nearly 3.5 billion years old. Not only are these the oldest fossils on record, but they also have given researchers the earliest direct evidence of life on our planet.

In 1982, J. William Schopf, PhD, paleobiology professor at the University of California at Los Angeles, gathered the rocks holding the fossils from the Pilbara Craton (a craton is a large, stable piece of the planet’s crust), near the Marble Bar. It was in chert layers of the Apex Basalt formation, which is the part of the craton that forms the core of the Australian continent.

Dr. Schopf, director of UCLA’s Center for the Study of Evolution and the Origin of Life, and his colleagues, published their first findings about the microscopic fossils in 1993, establishing their unique shapes. In 2002, the UCLA team published more evidence of the 11 specimens of microbe fossils. Skeptics denied that they represented life.

For ten years, John W. Valley, PhD, and colleagues at the University of Wisconsin-Madison, developed painstakingly slow new techniques to analyze the fossil samples’ carbon isotopes using one of the few secondary ion mass spectrometers in the world, and settled the matter of their biological nature and age beyond reasonable argument. This work suggests that life could be common throughout the entire universe and that life on Earth dates back much earlier than previously determined.

More Info: phys.org