Oldest fossils ever discovered

[Plazma Inferno!]

Scientists have just unearthed what they claim to be the oldest fossils ever found on our planet. They're so ancient they predate the next oldest finds by roughly a quarter-billion years.
These newly uncovered fossils are 3.7-billion-year -old traces of ancient microbes, and were found under recently melted perennial snow in southwest Greenland. The fossils were discovered by a team of geologists and paleontologists led by Allen Nutman at the University of Wollongong in Australia.
These fossils are tentative proof that life formed very quickly after a violent and chaotic era in our planet's history—a period of intense asteroid shelling called the Late Heavy Bombardment that ended 3.8 billion years ago.

http://www.popularmechanics.com/science/environment/news/a22646/oldest-fossils-ever-discovered/

Paper: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19355.html

 

[Yazata]

Scientists have just unearthed what they claim to be the oldest fossils ever found on our planet. They're so ancient they predate the next oldest finds by roughly a quarter-billion years.

There's indirect chemical evidence that life may be even older than that.

These newly uncovered fossils are 3.7-billion-year -old traces of ancient microbes, and were found under recently melted perennial snow in southwest Greenland. The fossils were discovered by a team of geologists and paleontologists led by Allen Nutman at the University of Wollongong in Australia.

At least these newly discovered structures resemble stromatolites. That doesn't prove that they were. The Nature abstract mentions evidence of carbon sequestration too, which would make the morphological evidence much stronger.

These fossils are tentative proof that life formed very quickly after a violent and chaotic era in our planet's history—a period of intense asteroid shelling called the Late Heavy Bombardment that ended 3.8 billion years ago.

Right. That's what makes me a little skeptical about these early dates for the appearance of life. Even procaryotic bacterial life is so exceedingly complex chemically, that I can't imagine it just appearing without a protracted running start.

In other words, I have trouble imagining the origin of life as a single event that took place at a single point in time, when all kinds of very specific proteins formed and came together in functional ways, along with nucleic acids that somehow already possessed a working genetic code, inside lipid bilayer cell membranes, the whole complex assemblage able to metabolize carbon, extract energy from the environment and reproduce itself from the very beginning.

I'm inclined to think that life is either more recent than researchers currently hypothesize, or else it isn't native to Earth at all.

 

[Gawdzilla Sama]

Carbon found in 3.95bn-year-old rocks is remnant of ancient life – researchers

Life may have gained a foothold on Earth more than 4bn years ago, according to researchers who believe that fragments of carbon found in rocks in Canada are remnants of ancient organisms.

Researchers in Japan analysed graphite particles in rocks from the Saglek region of northern Labrador and found that they contained potential traces of life. In work last year, the team dated the band of rocks to 3.95bn years old.

The claim that these rocks contain remnants of life now faces intense scrutiny from other scientists, but if the research published in Nature stands up, it suggests that the first organisms to emerge on Earth did so during one of the most violent periods in the planet’s history. Until 3.8bn years ago, the Earth was pounded by asteroids and comets left over from the formation of the solar system.

Yuji Sano, a senior researcher at the University of Tokyo, said that until now the oldest evidence for life on Earth stood at 3.8bn years, and coincided with the end of the so-called Late Heavy Bombardment. “It may be difficult to create life before 3.8bn years ago due to the bombardment, which may destroy early life,” he said. “But now it is 4bn years. Life started on Earth during the heavy bombardment of meteorites, which is amazing.”

Or perhaps it is not. The Japanese team base their claims on the sole discovery that some pieces of graphite bore the same carbon isotope ratios that are seen in living organisms. Life favours the lighter version of carbon, called carbon-12, over the heavier version, carbon-13, and when it dies, becomes sludge, and eventually forms rock, the material preserves the telltale carbon signature. But graphite can form with a skewed ratio of carbon isotopes without life’s helping hand. It can happen through the glacial action of geochemical processes or crash-land in meteorites.

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