New ancient fossilized traces of microbial life has been found to date back to at time in the Precambrian Period, known as the Eoarchean Era, about 3.7 billion years ago. This means life existed, in its most primitive form, on the Earth less than a billion years after it first formed. This is a quite remarkable find, because nothing like it has ever been discovered before.
Up to this point in time, the oldest bacterial fossils were dated to be only about 3.3 billion years ago, a 250 million year gap. The fossils were found in snow that had not melted for an untold amount of time. It was located in glaciers in Greenland. They were discovered by a team of scientists from Australian University of Wollongong. The team was headed up by Dr. Allen Nutman, a paleontologist. He outlined his find in the scientific journal, Nature. Read the brief Popular Mechanics take on this.
It turns out life has seemingly always occurred, even after major catastrophic events of the distant past. The scientists are astonished, because of how quickly this find proves life sprang up after major cataclysms on the planet. For one thing, until about 3.8 billion years ago, the Earth was under constant impacts from clouds of asteroids that filled the Solar System. This is termed the ‘Late Heavy Bombardment’ period.
At NASA’s Jet Propulsion Laboratory (JPL), scientist Abigail Allwood wrote a scientific paper about this discovery. She believes that if life can exist on an Earth that did not yet have oxygen, then life is not that rare and unlikely, in her opinion. She related that it now seems likely that if there is any resource life can exploit, it will run away with it.
The fossilized microbes in question do not seem to be in rock that anyone would usually notice. The main sign is a certain wavy pattern that vaguely looks like a mountain range. Those one inch tall patterns are called stromatolites. They are the very first type of microbe ever to live on Earth. Nutman’s team has determined that they lived in pools of primordial seawater soup pools or at least upon the shores of such lakes. stromatolites are actually quite difficult to identify and date.