The origin of the early settlements of the Danish Autonomous Archipelago lost in the middle of the North Atlantic is uncertain.

The arrival of the Vikings, who came from northern Europe in the middle of the 9th century AD, remains the first direct and documented evidence of human occupation.

Several clues nevertheless suggest an earlier colonization, and came from the British Isles: stories evoking the presence of Irish monks a hundred years before, place names derived from Celtic, Celtic engravings found on graves ...

In 2006, DNA analyzes also revealed a "strong genetic asymmetry" within the Faroese population, heir to Scandinavian genes on the side of her paternal ancestors, Celtic on the maternal side.

But it lacked irrefutable archaeological evidence, which a study published Thursday in the journal Communications Earth & Environment said to provide.

Sheep near the village of Hellur, on the island of Eysturoy, in the Faroe Islands, in October 2021 Jonathan NACKSTRAND AFP / Archives

A team of researchers, passionate about the climatic and human history of the North Atlantic islands, set off to excavate the sediments of a lake on the island of Eysturoy, one of the eighteen in the archipelago. of 1,400 km2.

Traces of fecal matter

The location, near the remains of an old farmhouse from a well-known Viking archaeological site, was not chosen at random.

"We concentrated our efforts there, thinking that if the Vikings had settled there, it is because the place must have been attractive also for previous occupants", tells AFP the paleoclimatologist William D'Andrea, co -author of the study.

And they got it right: while combing the sedimentary layers of the lake, they unearthed tiny fragments of sheep DNA, and found a concentration of biomarkers from their feces.

Trapped for centuries in these earthly "archives".

Thanks to rapid sequencing, they were able to trace them back to between the end of the 5th and the beginning of the 6th century AD.

Traces of fecal matter, specific molecules produced by the digestive system of mammals, constitute according to the study an "unequivocal" indicator of human and animal presence - unlike pollen or charcoal for example, which can be modified by erosion or climatic variations, and are therefore less robust.

A road leading to the village of Hellur, on the island of Eysturoy, in October 2021 in the Faroe Islands Jonathan NACKSTRAND AFP / Archives

In these isolated islands halfway between Norway and Iceland, all mammals have been introduced by humans.

"There were no wild sheep before the first settlements," confirms William D'Andrea, who works at the Lamont-Doherty Earth Observatory at the American University of Columbia in New York State.

Its dating of feces coincides with an evolution of the vegetation at the same period, revealed by an increase in the presence of DNA of grasses and the disappearance of woody plants: two clues suggesting that these first settlers grazed cattle on the islands. , between 300 and 400 years before the Viking landings.

It remains to find scientific proof that these first settlers were indeed Celts, specifies Professor D'Andrea.

The village of Tjornuvik on the island of Eysturoy, in the Faroe Islands in 2017 MENAHEM KAHANA AFP / Archives

It will be difficult, as "the causes of human migrations are diverse, intertwined, linked to climatic, political and resource issues, or quite simply to the spirit of human exploration ... Wouldn't that be great to be able to ask them? ".

© 2021 AFP