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Two years ago a group of scientists led by Allen Nutman claims to have found supposed Fossils dating from 3.7 billion years ago in Greenland. But recent studies and analysis of a new team scientists seemed to prove that it can be just a pile of rocks.
This discovery was very important because it led even further to the origins of the oldest evidence of life on Earth. Fossils found in Greenland suggested the presence of microbial life in rock samples. And that takes the age of the oldest stromatolite from about 3.45 billion to 3.7 billion years.
The new discovery of the team
Stromatolites are stratified mounds built by communities of microbes in shallow water. The rocks found in Greenland were cone-shaped distortions of rock layers and, based on different characteristics, the Nutman team concluded that they were stromatolites. This type of formation was common billions of years ago, when microbes reigned on Earth. The discovery seemed to belong to that time.
The new team of scientists conducting tests on the Greenland discovery is led by NASA astrobiologist Abigail Allwood. It is important to know that she was part of the group that discovered Australian stromatolites considered the oldest evidence of life at present. She studied the shape of the rocks of Greenland with a three-dimensional examination. This allowed him to analyze the shape of the characteristics of the rock and not just its surface.
This new view of research seemed to indicate that the characteristics of 'stromatolites' had been created by intense pressure between the rocks. This pressure squeezed and twisted the stone into strange shapes. Nutman's team worked with the face of the rock outcrop, while that of Allwood sawed a block for three-dimensional study.
Stromatolites should form cones, domes or round pillars. But when the rock block was sawn, what looked like a cone for Nutman turned out to be more peak-shaped. Asymmetric bumps that extend in one direction are common when a tectonic force squeezes a layer of rock horizontally to crease it. And stromatolites certainly do not have that kind of shape.
conclusions
The Allwood team trial showed that the rocks found in Greenland do not have the distinctive pattern of stratification layers expected from fossilized microorganisms. The explanation that the stones discovered by the Nutman team has been the scene of many tectonic abuses because they were fresh sediments, seems to correspond to all the new data.
"It's a classic scenario comparing apples and oranges, which results in an inevitable result that our observations do not match," Nutman said, according to the Associated Press.
Basically, there are a number of geological explanations for structures that do not involve living organisms. Nutman's team opposes these findings, claiming that the Allwood team analyzed the wrong fossil samples. But as it is science, sooner or later, someone will prove what statement is accurate. We just have to wait to see what further analysis can conclude.
Source: arstechnica
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