World's oldest fossils found in Greenland

Greenland's ice sheet is experiencing record levels of melting due human-caused global warming, which is actually helping scientists search for clues of Earth's origins at the same time that it threatens to trigger catastrophic levels of sea level rise. Why did life evolve?

"This discovery represents a new benchmark for the oldest preserved evidence of life on Earth", Professor Van Kranendonk said.

The tedious journey to finding an answer has thrown out several bits of valuable knowledge, such as what defines a fossil.

If you didn't know what to look for, you'd probably glance right past these new fossils without ever noticing them.

The new fossils are exciting for so many reasons. There are also trace fossils - evidence of an animal's footprints or faeces. "It's not a huge assumption to say that any life on Mars at this time was also single-celled micro-organisms". Its rocks are certainly ancient, but they've also been put through the wringer, warped and distorted by intense heat and pressure. "We have a much better window back in time, thanks to what these folks did".

Australian and United Kingdom scientists have dug up the oldest fossils found on Earth to date - 3,700-million-year-old sedimentary formations created by clumps of bacteria - which predate the current earliest fossils by a whopping 220 million years, and suggest life originated here more than 4,000 million years ago. In fact, they would be the descendants of earlier life forms. An example of such formation is a coral.

"Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet", she said.

These rocks contained stromatolites, or layered structures produced by microorganism communities that trapped and bound sediments.

Stromatolites in the Soeginina Beds (Paadla Formation, Ludlow, Silurian) near Kübassaare, Saaremaa, Estonia. In that paper, Professor Nutman and his colleagues Vickie Bennett from the Australian National University and Martin Van Kranendonk from UNSW, write that by "3700 million years ago life already had a considerable prehistory and supports model organism chronology that life arouse during the Hadean [epoch] more than four billion years ago". They were discovered in the 1950s and dated by the early 1990s.

"Mars was wet", Nutman told the Washington Post.

The rocks were part of the seafloor 3.7 billion years ago, and the wavy lines, just a few centimetres across, would be remnants of primordial microbial colonies called stromatolites. According to Dr. Allen Nutman, one of the geologists credited with making the discovery, the possibility of finding older fossils than these is extremely unlikely, and there's plenty of information that's expected to be forthcoming from the investigation into figuring out the story behind these fossils. Nutman said that "we are just looking at a fortunate survivor of the early life record". Perhaps it was during this warm, tranquil period that key steps in the origin of life occurred.

The team used sophisticated techniques to carefully date the layers of rocks above and below the fossils. The largest of these impacts, at 4.5 billion years ago, tore a piece from Earth that became the moon. "So life either had to start earlier, or evolution is more rapid than you might expect", mentioned astrobiologist Sara Walker from Arizona State University. Previous genetic molecular clock studies point to such a time as well.

About 3.7 billion years ago, Mars was made up of river and oceans.

There is an even exciting prospect. If life could form under unimaginably violent conditions on Earth, it is not picky.

'Give life half an opportunity and it'll run with it. Maybe the rovers of the future will beam back pictures of Martian stromatolites.

Another thing that would be provided with the confirmation is life appeared soon after earth formed.