Japanese scientists found in the north-east of Canada deposits of organic rocks, indicating that life could exist on Earth at least four billion years ago.

The Japanese scientists succeeded in obtaining new data by analyzing the composition of carbon in graphite and carbonate minerals from the eoarchea from the Labrador Peninsula. This discovery refutes the view that the very first traces of living organisms on our planet appeared 3.75 billion. years ago, as was. The results of the research were published in the journal Nature.

The first living organisms appeared on Earth during the Archaean era, and so far there is no generally accepted point of view about how and when life began. To date, there are several fossil evidence that microbes already existed in the primary ocean of the Earth about 3.4 billion years ago, but many scientists believe that life could have arisen much earlier.

Three years ago, Japanese geologists studying samples of graphite from Greenland found signs that life already existed on Earth about 3.7 billion. years ago. In 2016, scientists found the first irrefutable evidence of the existence of life in that era, and in 2015 they found in Australia, the probable traces of life that inhabited the oceans of the earth 4 billion. years ago.

Akizumi Ishida of the University of Tokyo and his colleagues who discovered traces of life in Greenland continued their excavations, trying to find other deposits of graphite containing the remains of the first living organisms on Earth.

Scientists searched using the already well-developed method, studying the structure, chemical and isotope composition of the oldest rocks of the Earth, formed on the most ancient continental platforms. As a rule, graphite of biogenic origin produces two things - a low proportion of heavy "carbon-13" and a special structure of its grains, which includes many elements similar in shape and size to bacterial cells and archaea.

Similar pools of Akizumi Ishida and his like-minded people were found in the northeast of Canada, near the town of St. John's, the capital of the island of Newfoundland. Inside the local rocks, formed approximately 3.95 billion. years ago, scientists found many small voids containing graphite.

This discovery caused them to split about one hundred and fifty cobblestones from Newfoundland and to study in detail the isotopic composition of these inclusions and analyze their shape. In total, the Japanese geologists found about three dozen graphite deposits, which corresponded to both, and the criterion of their biological origin.

A large number of graphite samples allowed Japanese scientists to get an idea of ??what the life that gave birth to them looked like and in what conditions it lived. For example, quite high proportions of yttrium and some other rare earth metals indicate that the first microbes of the Earth did not live in freshwater lakes, but in salt water. Today many scientists doubt the possibility of this, pointing to the absence in the primary ocean of the Earth of many critical elements, such as boron or manganese, present in large numbers on land.

Despite all the importance of the results of the analysis, a low amount of carbon is just an indirect evidence of the existence of life. To confirm their theory, the researchers conducted a series of tests, studying the isotopic composition of graphite grains and comparing it with the data of the remaining layer. Grains differed from the environment by 25 ppm.

In addition, the low concentration of heavy carbon in these deposits indicates that these bacteria fed on hydrogen or pure organic matter, using their energy in order to convert the molecules of carbon dioxide into carbon monoxide and use it to synthesize amino acids and other elements necessary for life. According to Internet media.