For the first time, scientists have drilled into an underwater mountain to collect a record-breaking chunk of Earth’s mantle – a rocky core more than 3,280 feet (one kilometer) wide.
This extraordinary feat was accomplished by drilling in the Atlantis Massif, an underwater mountain range located on the Mid-Atlantic Ridge beneath the North Atlantic Ocean. By aligning drill bits at this site, geologists have drilled a 4,156-foot-deep (1,267 meters) hole in the mountain and extracted serpentine – an “amazing” amount of metamorphic rock that forms at deep tectonic plate boundaries – from Earth’s interior.
Despite its groundbreaking results, it is not the deepest drill ever conducted on the ocean floor, and technically, it is not drilling into the Earth’s mantle. Instead, the researchers exploited the “tectonic window”—the area where mantle rock is pushed above its usual resting place—to sink the drill and extract the material.
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Geologists write in a posting blog. “The Atlantis Massif offers a rare access advantage, as it is composed of mantle rock that has been uplifted close to the surface by very slow seafloor spreading processes.”
Geologists have been trying to extract large chunks of the Earth’s mantle since 1961, when scientists at Project Mohole tried to drill beneath the Pacific Ocean to reach the Mohorovicice discontinuity, the area where the Earth’s crust gives way to the mantle. Unfortunately, the project exercise only reached 601 feet (183 m) below the seafloor before sinking and the attempt was aborted. After that, a number of subsequent offshore drilling efforts also ended in failure.
This means studying parts of the Earth’s mantle for evidence of processes as varied as volcanism and planet Earth. force fieldScientists have to rely on chunks of rock thrown up by volcanic eruptions, all of which change as they travel to the surface.
The geologists, members of the International Ocean Discovery Program aboard the scientific drilling vessel JOIDES Resolution, began their mission to the Atlantis Massif not because they wanted to extract mantle core, but because they were looking for the origins of life on Earth. The Massif’s rock contains olivine, which reacts with water in a process called serpentine to produce hydrogen, an important food source for microbial life.
However, shortly after May 1, when they anchored their drill in a horizontal rift in the ocean floor, the researchers extracted a record-breaking core of upper mantle rock that extended more than 3,280 feet.
The rock is primarily peridotite, a coarse igneous rock filled with olivine and pyroxene which is the most common rock type in the upper mantle. Some signs of altered rock through interaction with seawater could mean they originate in the lower crust rather than the upper mantle, but scientists are still looking for deeper samples to confirm their findings. Within these rocks is a treasure trove of information that geologists will seek to find out more information about the inner workings of the Earth.
“The magnitude of this history has certainly not been lost on our science team, many of whom are experienced field researchers and believe this will be very important data for many generations of scientists to come,” the geologists wrote in a blog post.
2023-06-08 18:03:10
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