Science

Stromatolite fossils push back date for start of life on Earth

Stromatolite fossils push back...
A team of scientists claim to have discovered the world's oldest fossils that are around 3.7 billion years old, pushing back the fossil history to near the start of Earth’s geological record
A team of scientists claim to have discovered the world's oldest fossils that are around 3.7 billion years old, pushing back the fossil history to near the start of Earth’s geological record
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A team of scientists claim to have discovered the world's oldest fossils that are around 3.7 billion years old, pushing back the fossil history to near the start of Earth’s geological record
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A team of scientists claim to have discovered the world's oldest fossils that are around 3.7 billion years old, pushing back the fossil history to near the start of Earth’s geological record
Researchers hold a sample of the Greenland stromatolite fossil
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Researchers hold a sample of the Greenland stromatolite fossil

In a remote, isolated region of Greenland, where ancient rocky outcrops have recently been exposed after a perennial snow thaw, scientists claim to have found fossil proof of the oldest life ever discovered. Consisting of fossilized blue-green algae colonies known as stromatolites, the 3.7 billion year old petrified remains are more than 200 million years older than the world's previous oldest stromatolite fossils and are set to rewrite the record books on the age of life in Earth's earliest seas.

Located along the edge of Greenland'sicecap in an area known as the Isua Greenstone Belt, the stromatolites are clear evidence of an early shallow sea that once existed in the area many thousands of millennia ago. Their discovery pushes back the point at which life began to little more than a few hundred million years after the Earth was first formed some 4.543 billion years ago.

"The significance of stromatolites is that not only do they provide obvious evidence of ancient life that is visible with the naked eye, but that they are complex ecosystems," said Professor Allen Nutman of the University of Wollongong, and leader of the team. "This indicates that as long as 3.7 billion years ago microbial life was already diverse. This diversity shows that life emerged within the first few hundred millions years of Earth's existence, which is in keeping with biologists' calculations showing the great antiquity of life's genetic code."

Researchers hold a sample of the Greenland stromatolite fossil
Researchers hold a sample of the Greenland stromatolite fossil

Stromatolites (meaning, "layered rock") are slow-growing rigid structures formed by single-celled cyanobacteria microbes (blue-green algae) that trap sediment on their surfaces. Over very long periods of time the captured sediment reacts with calcium carbonate in sea water to form limestone, which grows at a rate of around 5 cm per 100 years.

The previously oldest known fossils are also stromatolites found embedded in Archaean era (4 billion to 2.5 billion years ago) rocks of Western Australia, and are around 3.5 billion years old. As cyanobacteria are among the easiest microfossils to recognize, especially as their form changed very little over millions of years, these same organisms were clearly distinguishable in the latest fossil discovery.

"The structures and geochemistry from newly exposed outcrops in Greenland display all of the features used in youngerrocks to argue for a biological origin," said Professor Van Kranendonk, another member of the team from the University of New South Wales Australian Centre for Astrobiology.

"This discovery turns the study of planetary habitability on its head," said Associate Professor Vickie Bennett, from Australian National University's Research School of Earth Sciences. "Rather than speculating about potential early environments, for the first time we have rocks that we know record the conditions and environments that sustained early life. Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet."

Though the discovery of the Greenland fossils should help provide a much greater comprehension of the early variety of life on Earth, the researchers also believe that the findings may have implications for understanding possibilities of life on an early Mars.

"This discovery represents a new benchmark for the oldest preserved evidence of life on Earth," said Professor Van Kranendonk. "It points to a rapid emergence of life on Earth and supports the search for life in similarly ancient rocks on Mars."

The findings will be published today (September 1st) in the journal Nature.

Source: University of Wollongong

4 comments
jgb
Push it back another 100 billion years and it still won't be enough to mathematically justify evolution.
Lbrewer42
May we PLEASE get back to factual science? The dates they use for these finds are ridiculously inflated. Do some legitimate research into the assumptions which are used by our current radiometric dating methods and you find major problems. The methods we use are invalid since we cannot guarantee the ratio of the elements and their isotopes in a sample were what we have to ASSUME them to be in order to use the dating method. The methods also are invalid b/c they require the isotopes to have always, throughout all time, to have been existing appearing in nature in the same ratios (such as C14 is made by cosmic rays on atmosphere is nitrogen - and we know cosmic radiation has not always been an exact constant - therefore the whole amount of C-14 to C-12 ration in objects has varied and implies false dates). Add to this the results of dates being "calibrated" to make them fit in with the rest of the flawed dates already "established" (REALLY scientific there), and you end up with a giant farce. But this is where government money goes - to those who only please the "politically correct" (no matter the field of study. So the Dark Ages of modern "Science" continues. We are fed propaganda using the label of science to worship at the altar of the almighty dollar. Never has there been even ONE example of an animal or fossil changing from one KIND (different genetic pool) to another. Evolution requires this. And even with all of our hi tech gene manipulation, we cannot artificially FORCE an animal to do so. We have done everything we can to the fruit fly genome. And we get... abnormal fruit flies that are blind, wingless, a pair of useless wings, etc. Never anything positive has come from it, never have we been able to make them into a new kind of insect. We cannot make them have stingers, tails, etc. Every cell in their body has the genetic code testifying to it being nothing but a fruit fly. All changes shown are already in their gene pool. Selective breeding can bring these out - but its still a fruit fly. Yet the almighty dollar says changing from one kind into another (making new gene pools to make new kinds of animals) happened all by itself... and not just once - but as a continuing process.
Grainpaw
Apparently not enough government money has been spent on science education.
Paul Muad'Dib
The real problem is a form of anti-education popular in the US.