Rudimentary life may have made its way on Earth 3.95 billion years ago, a time when our planet was being bombarded by comets and had barely any oxygen. Well, in that infernal scenario, when the atmosphere exerted a pressure up to 100 times more than the current one, living beings existed. This is the conclusion of a team of scientists led by the University of Tokyo (Japan), which has analyzed some ancient accumulations of graphite found in rocks of Labrador, in eastern Canada, from 3,950 million years ago and whose explanation is no other than to have been produced by living beings.
The results, published in the journal Nature , would represent the oldest fossil evidence of life on Earth.
Previously, we had witnessed the announcement of the earliest earliest traces of life in a region of Quebec, estimated to be between 3.8 billion and 4.3 billion years old, by another team of researchers, although an author of the new study called that “very controversial” dating process.
Now, the discovery of graphite of biological origin is, in the own words of Tsuyoshi Komiya, the leader of the present work, the oldest evidence of life that, in addition to confirming the existence of microorganisms 3,950 million years ago, offers us clues about what type of beings could be.
Investigation obstacles
The fossil evidence of early organisms is rather meager and the rocks that still remain from that period are usually poorly preserved. One of the biggest difficulties scientists face is proving that organic remains were produced by living organisms rather than geological processes.
This field of study is aimed not only at identifying the beginning of life on our planet, but also at shedding light on the possibility that life has existed – or still exists – on other planets such as Mars.
In this work, the experts studied graphite, a form of carbon used in lead pencil (lead pencil), in rocks located at the Saglek Block in Labrador, Canada.
They measured its isotopic composition, the signature of chemical elements, and concluded that the graphite was “biogenic”, that is, a product of living organisms and not by geological development.
Of course, the identity of the organisms remains a mystery.
“We are going to analyze other isotopes such as nitrogen, iron and sulfur from the organic matter and accompanied minerals to identify the types of organisms. In addition, we can estimate the environment in which the organisms lived, analyzing the chemical composition of the rock itself”, Komiya clarifies.
If the findings are accurate, it means that life took hold of Earth just a geological second after its formation about 4.5 billion years ago.
Reference: Takayuki Tashiro, Akizumi Ishida Masako Hori Motoko Igisu Mizuho Koike Pauline Méjean Naoto Takahata Yuji Sano Tsuyoshi Komiya. Early trace of life from 3.95 Ga sedimentary rocks in Labrador, Canada, Nature (2017). DOI: 10.1038 / nature24019
