Scientists exploring areas of Greenland that were once covered in snow, but now are not, claim that they have found the oldest fossils on record. These are the fossilized echoes of microbial mats that existed 3.7 billion years ago. The research, published in Nature, says that the team discovered stromatolites 1-4 cm high that grew in shallow marine environments.
They made their find in July 2012 while doing field research in Isua, a region of Greenland so remote that they had to travel there by helicopter. The site is known for having some of the oldest rocks on Earth, in what is known as the Isua supracrustal belt. Allen Nutman, a University of Wollongong geologist who has studied the rocks there since 1980, said one day he and his colleagues were working at the site when they spied some outcroppings they'd never seen before. The formations had been exposed where the snow pack had melted — the result, Nutman said, of the global warming that is so pronounced in Greenland or of low levels of snowfall the previous winter.
They examined the outcropping and immediately saw something intriguing: conical structures, just one to four centimeters (less than two inches) high. They look like fossilized microbial mats — basically, pillows of slime — known as stromatolites, which are formed today by bacterial communities living in shallow water.
If their findings hold up, this will push back the oldest known fossil record of live 200 millions years. More impressively, if they prove to indeed be ancient stromatolites, they would be the structures evolved from even earlier life. Part of what makes any find like this extraordinary is that finding rocks that are themselves older than 3 billion years is very difficult because of the nature of how the earth grinds up and recycles itself through the process of plate tectonics. Of course, this finding will be debated, as is all scientific study.