Scientists Drill Deeper Into Earth’s Mantle Than Ever Before, Probing for the Origin of Life on Earth

In the spring of 2023, an expedition of scientists got closer to making a Journey to the Center of the Earth than ever before. Aboard the ocean-drilling vessel JOIDES Resolution, they took a cylindrical core sample of the Atlantis Massif, an underwater mountain in the Atlantic Ocean west of the mid-Atlantic Ridge.

Initially, they planned to bore down only 656 feet for fear that their drill might jam. But when no such problem occurred, they continued—and the team ended up penetrating 4,160 feet (0.7 miles) into the seabed, deeper than anyone has ever drilled. The scientists, whose record achievement was published in the journal Science last week, say the cores they pulled up might hold clues to the origin of life on Earth.

“We did it,” Frieder Klein, an expedition team member at the Woods Hole Oceanographic Institution, tells New York Times’ William J. Broad. “We now have a treasure trove of rocks that will let us systematically study the processes that people believe are relevant to the emergence of life on the planet.”

The cores recovered by the expedition—led by the International Ocean Discovery Program—originate in Earth’s mantle, the planet’s largest layer. Made of mostly solid rock, the mantle is typically inaccessible, as it sits between the crust and core. But at some places deep in the oceans, the parting of tectonic plates causes the mantle to be exposed. In these underwater habitats, such as the Atlantis Massif, mantle rocks interact with salty seawater in chemical reactions that produce life-fueling molecules.

“There’s a kind of chemical kitchen in the subsurface of Atlantis Massif,” Johan Lissenberg, lead author of the study and a geologist at Cardiff University in Wales, tells New Scientist’s Chen Ly.

When seawater reacts with mantle rocks beneath the Earth’s surface, it can produce hydrogen and methane, which bubble back into the ocean through hydrothermal vents. The scientists’ drill site was located near a field of these vents in tower-like structures known as the “Lost City.” There, these gases support microbial life, which in turn feeds small invertebrates in the ecosystem.

“One suggestion for the origin of life on Earth is that it could have happened in an environment similar to Lost City,” study co-author Andrew McCaig, a geologist at the University of Leeds in England, tells Reuters’ Will Dunham.

The team’s initial research sheds light on how olivine, a mineral that’s abundant in their sample of mantle rocks, kick-starts these chemical reactions. Understanding these processes might have implications beyond life on Earth—it could relate to the possibility of extraterrestrial life, Klein tells the New York Times.

Deborah Kelley, an oceanographer at the University of Washington who was not involved in the study, tells the New York Times that the research is “really important” and “lays a foundation for new understanding.”

Examining the rock composition of the samples can also reveal insight into the movement of the mantle, which is responsible for volcanoes and earthquakes, Lissenberg tells Live Science’s Stephanie Pappas.

Already, preliminary analysis of the sediment core has uncovered lower levels of the mineral pyroxene than what has been found in other parts of the world, along with higher levels of magnesium. These findings indicate this region of the mantle underwent a higher amount of melting than the scientists would have expected.

“It’s too early to say anything really specific, because the results are not yet in,” Lissenberg adds to the New York Times. “But we’ll find out. That’s the excitement.”

Margherita Bassi | READ MORE

Margherita Bassi is a trilingual storyteller and freelance journalist with a particular interest in ancient history, astronomy and human interest stories.