A new geological study from the University of Copenhagen has shown that the oldest Norse bedrock comes from Greenland. This discovery sheds light on the formation of continents and the unique presence of life on Earth compared to other planets in our solar system.

In an isolated Finnish outcrop hidden among some of Northern Europe’s oldest mountains, scientists have found traces of a previously hidden part of the Earth’s crust that points back more than three billion years in time and as far north as Greenland.

These traces were found in the mineral zircon; Chemical analysis showed researchers from the Department of Geology and Natural Resource Management that the “foundation” on which Denmark and Scandinavia are based was probably “born” in Greenland around 3.75 billion years ago.

“Our data show that the oldest part of the crust beneath Scandinavia comes from Greenland and is around 250 million years older than we previously thought,” says geologist Professor Todd Waite from the Department of Earth Sciences and Natural Resource Management.

The researchers’ study of zircon showed that its chemical signature matched some of the oldest rocks on the planet, found in the North Atlantic Craton in western Greenland.

“The zircon crystals we found in river sand and rocks in Finland have signatures that suggest they are much older than those found in Scandinavia but match the age of rock samples from Greenland. At the same time, results from three independent isotopic analyzes indicate that Scandinavia’s native rocks are most likely to be related to Greenland.” confirms that they are linked,” says researcher Andreas Petersson from the Department of Earth Sciences and Natural Resource Management.

Water world without oxygen

Denmark, Sweden, Norway and Finland lie on a part of the earth’s crust known as the Fennoscandian Shield or Baltic Shield. Researchers believe it broke away from Greenland as a “seed” and progressed over hundreds of millions of years until it “rooted” into where Finland is today.

Here the plate grew as new geological material accumulated around it until it became Scandinavia. At the time the crust broke away from Greenland, the planet looked completely different than it does today.

“Earth was probably a watery planet, like in the movie Water World, but there was no oxygen in the atmosphere and no crust. But it’s so far in the past that we can’t be sure what it was really like,” says Todd Waite.

Even the fact that Earth has a continental crust made of granite is quite special, according to researchers, when they look into space and compare it to other planets in our galactic circle.

“This is a unique situation in our solar system. Evidence of liquid water and granitic crust are key factors for identifying habitable exoplanets and the possibility of life beyond Earth,” explains Andreas Petersson.

Continents are the key to life

The new study adds pieces to the puzzle of primitive continents that began long before life on Earth actually developed, but largely paved the way for human and animal life.

“Understanding how continents form helps us understand why our planet is the only inhabited planet in the solar system. Because without permanent continents and the water between them, we would not be here. Indeed, continents influence ocean currents and climate, which are vital for life on Earth,” says Andreas Petersson.

In addition, the new study adds to a growing body of research that rejects the methods hitherto used to calculate how continents grew, especially during the first billion years of Earth’s history.

“The most commonly used models suggest that Earth’s continental crust began to form during the planet’s formation about 4.6 billion years ago. Instead, our and some other new research shows that chemical signatures indicating the growth of continental crust can only be detected after about a billion years. This means we may need to rethink much of what we think about how the first continents evolved,” says Professor Waite.

At the same time, the study’s results complement previous studies that found similar “seeds” from ancient tree bark in other parts of the world.

“Our research gives us another important clue into the mystery of how continents form and spread across the Earth, particularly in the case of the Fennoscandian Shield. But there is still a lot we don’t know. Similar seeds have been found in Australia, South Africa and India, for example, but they are all the same.” “We are not sure whether they came from their ‘birthplace’ or whether they arose independently of each other in various parts of the Earth. This is something we want to investigate further using the method we used in this study,” Professor Waite concludes.