For the first time, an international team of scientists recovered a long section of rocks that originated in the Earth’s mantle.
This layer just below the crust is the largest part of the planet’s interior, so understanding it can tell us a great deal about some of Earth’s more explosive characteristics. This nearly continuous 4,160 feet (1,268 meters) of mantle rock is described in a study published this month in the journal Science.
The rocks were recovered from a section of the seabed where rocks from the Earth’s mantle were exposed along the Mid-Atlantic Ridge. This ridge along the floor of the Atlantic Ocean stretches 10,000 miles from the Arctic to the southern tip of Africa and is part of the longest mountain range on Earth. According to NOAA, mid-ocean ridges like this one are geologically important, since they occur along the type of plate boundary where new ocean floor is created as the plates spread apart.
These cylindrical samples of rock, sand, and other sediment from the ocean floor are like a timeline of our planet’s history.
“When we recovered the rocks... it was a major achievement in the history of the Earth sciences, but, more than that, its value is in what the cores of mantle rocks could tell us about the makeup and evolution of our planet,” says Johan Lissenberg, study co-author and geologist at Cardiff University in Wales. “Our study begins to look at the composition of the mantle by documenting the mineralogy of the recovered rocks, as well as their chemical makeup.”
Since the core was drilled, the expedition team has been compiling an inventory of the mantle rocks to better understand their composition, structure, and context.