which once covered 15 million square miles—about a quarter of the Pacific Ocean. For millions of years, it was believed to have been completely consumed by subduction, the process in which one ...

G eoscientists have used earthquakes to study the composition of the lower portion of the Earth’s mantle under the Pacific ...

The Earth’s mantle, stretching up to 1,800 miles thick and making up a whopping 84% of the planet’s volume, used to be ...

Mantle The mantle is the layer of the ... the crust has cracked and split into many different pieces called tectonic plates. These plates can be oceanic, meaning they're found mainly under the ...