Ancient Fossils May Actually be Rocks

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A few years ago, a team of researchers discovered a new fossil, thought to be a proof that life on Earth may have started earlier than we initially thought. It was estimated that the structures found in Greenland were 3.7 billion-year old and they seemed to have a biological origin.

A new study by a different team states that the structures may be in fact actual rocks.

The structures were found by the first team in the Isua supracrustal belt in Greenland, and carbon dating revealed that they were 3.7 million years ago. The researchers concluded that they were stromalites, which are fossils of small clusters formed by single cell organisms and biofilms.

The oldest fossils found before came from the Strelley Pool Formation in Australia and are 3.45 billion years old.

When fossils are this old, it is very hard to separate them from normal rocks at a chemical level since there is no DNA or protein to confirm that the structure may have been alive. In this case, it is the answer can be found in the morphological features of the fossils.

Abigail Allwood, a leading astrobiologist, is not impressed by the Greenland discovery. While they do look like biological stromalites, the latest study argues that they are in fact a simple cross section of elongated triangular tubes. The claim is further reinforced by the fact that some of the structures were inverted, which should have been impossible if they were growing upward from what was previously thought to be an ancient seabed. The discovery is not expected when it comes to fossils which are there old. Some samples were also examined with the advanced PIXL instrument. The results showed that the samples don’t have the distinctive lamination patterns that are usually encountered in microorganism fossils.

As expected, the previous researchers are not happy with the new results, and argue that the other team analyzed the wrong samples.