According to researchers from Japan, a 3.95-billion-year-old discovery in northern Labrador in Canada will “rock” prehistory to its core.

The team examined the oldest known metasedimentary rocks in the area — the Saglek Block rocks — and found carbon atoms that they believe may contain the oldest traces of life on Earth. Metasedimentary rocks are rocks that crystallized due to the intense pressure of burial under increasing layers of sediment.

“These may represent the oldest evidence of life found yet on Earth,” said study senior author Tsuyoshi Komiya, a geologist at the University of Tokyo.

The team published their findings in the September 28 issue of the journal Nature.

Rock-solid evidence?

The Eoarchean period spanned from about 4 billion to 3.6 billion years ago. The very first signs of a primitive environment emerged from this era, as well as the planet’s oldest life forms.

Prior to this discovery, the oldest confirmed evidence of life ever discovered was in a 3.7-billion-year-old rock from Greenland back in 2016. While there were claims from 1996 of evidence of life in 3.8-billion-year-old rocks from Greenland’s Akilia Island, the results of that study remain inconclusive to this day.

Tsuyoshi and his team first focused their attention on the nodules of graphite in the rocks. As a recent article in the Washington Post explains:

Isotopes, often referred to as “flavors” of an element, are distinguished by their weight. Carbon 12, which has six protons and six neutrons in its nucleus, is lighter than carbon 13, which carries an extra neutron. Though both forms exist in nature, living things prefer the lighter isotope, which is easier to incorporate into molecules. For that reason, when scientists find a mass of graphite that’s dominated by carbon 12, they can guess that a long-dead organism was responsible.

Describing the find as “surprising and exciting,” Tsuyoshi believes that this discovery could change what we know about the Earth’s creation and the subsequent evolution of the various forms of life that populate it.– MF

Author: Tomas Pedrosa

A graduate of Information Design, a versatile writer, and an avid gamer, Tomas prides himself in his willingness to gain new experiences and perspectives, and to apply what he learns in his other pursuits. Curiosity, interest, and obsession—these are the mile markers that keep him going down his road.