Digging the deepest hole in the world

A giant project has begun: An international team will drill the ocean floor to recover samples from the mantle.

Scientists want to collect samples from the mantle of the Earth, which will be the first. To get there, they would have to dig the ocean floor for miles for at least 10 years.

The giant project is called MoHole to Mantle (M2M), and it is supported by many researchers, including four Canadians. “We know a lot about the Earth’s internal structure, but none of this depends on the analysis of real samples,” regrets John Jamison, professor of earth sciences at Memorial University and chair of the Canadian branch of the International Ocean Discovery Program. , The umbrella organization of the M2M Project. “We have good access to the rocks from the mantle that was pushed to the surface. But these rocks changed over the course of their journey, so they lost the information,” he says. Dr Jamieson is not among the four Canadian researchers, but he is aware of the entire project. This massive hole will also allow us to study the Mohorovic Discontinuity, a mysterious layer separating Earth’s crust from the mantle. It is located approximately 6,000 meters below the sea floor for M2M potential exploration sites (off Hawaii, Baja California, and Costa Rica). “We know that this layer exists by analyzing the propagation of seismic waves across the planet,” says Jamison. We can detect a very noticeable change between the cortex, border and mantle. “

The M2M project team admits: Some of the technologies required to dig in clays and rocks for years have not yet existed! “They will have to endure tremendous pressure and extreme temperatures [jusqu’à 250 °C]John Jamison says. The drill string has to withstand tremendous stress. “

So the date of the start of the excavations is still unknown. Even so, the group knows they will be able to count on them Container ChikioJapan Marine and Onshore Science and Technology Agency. “It wasn’t designed specifically for this project, but it was designed with the idea that it might one day be involved,” says John Jamison. En effet, l’Agence affirme que l’idée a été évoquée chez elle en 1959. Et preuve supplémentaire que le rêve ne date pas d’hier, dès la fin des années 1960, deux projets américains ont tenté d’atteindre le manteau, Without success. The deepest crater was 183 m (under 3000 m of water). Then it was the turn of the Russians and the Germans to dig, but on land. They stopped after 12 km and 9 km, respectively.

The M2M project has chosen oceanic drilling because the crust is thinner and more clearly documents major geological processes. “It’s a very risky project, but it’s also a high potential,” Jamieson says.