Understanding our planet’s geological “heart” inevitably requires studying the mantle — the vast layer sandwiched between the crust and the outer core, accounting for roughly 70% of Earth’s mass and 84% of its volume. Despite its decisive role in shaping continents, oceans, and volcanoes, direct access to mantle rocks had until recently remained almost an unattainable dream.
The breakthrough came in May 2023, when an international research team, working the International Ocean Discovery Program (IODP), succeeded in recovering a core sample from 1,268 meters beneath the Atlantic seafloor. The mission was carried out aboard the iconic research vessel JOIDES Resolution, chartered by the National Science Foundation in the United States.
The key site lies along the Mid-Atlantic Ridge, near the underwater mountain complex known as Atlantis Massif — one of the few places on Earth where the oceanic crust is thin enough for tectonic processes to expose mantle material closer to the surface. According to Popular Mechanics, the achievement represents the deepest mantle sample ever collected.
Initially, scientists aimed for a depth of just 200 meters — the previous drilling record in mantle rocks. However, progress proved faster than expected, and the team continued drilling until time constraints forced them to halt operations.
What the Rocks Revealed
Preliminary analysis, published in the prestigious journal Science, identified peridotites — primarily harzburgite, a rock formed through partial melting of mantle material. Gabbros, coarse-grained igneous rocks, were also found. Both rock types had undergone chemical alteration through interaction with seawater, offering valuable insight into the geochemical processes occurring deep within the lithosphere.
The Unreached Boundary
Despite the record, one of geoscience’s most ambitious goals remains unfulfilled: penetrating the Mohorovičić discontinuity (Moho), the distinct boundary between the crust and the “pure” mantle. Reaching this geological frontier would open an entirely new chapter in understanding Earth’s internal structure.
Yet the future of such missions is uncertain. Funding for further drilling operations with the JOIDES Resolution was not approved beyond 2024, leaving the scientific community with a remarkable achievement — and a lingering question mark.
As technology now allows science to “touch” the mantle, the question is no longer only how deep we can go, but whether there will be the will to continue the journey into the Earth’s depths.