April 17, 2024



At long last, ocean drillers exhume a bounty of rocks from Earth’s mantle

Long sections of intact mantle rocks recovered during IODP Expedition 399 will provide robust constraints on character of the mantle (Photo credit: Johan Lissenberg, Cardiff University & IODP)


In 1961, geologists off the Pacific coast of Mexico embarked on a daring journey to a foreign land—the planet’s interior. From a ship, they aimed to drill through the thin veneer of Earth’s crust and grab a sample of the mantle, the 2900-kilometer-thick layer of dense rock that fuels volcanic eruptions and makes up most of the planet’s mass. The drill only got a couple hundred meters below the seabed before the project foundered under spiraling costs. But the quest—one of geology’s holy grails—remained.