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Extreme Grinding

This is what’s left of a many-toothed tungsten drill bit after drilling through rock far beneath the seafloor. WHOI geologist Henry Dick recently led a voyage to the Indian Ocean, the latest stage of a scientific quest going back decades. The cruise, aboard the drill ship the JOIDES Resolution, was to try to drill through thousands of meters of rock to reach the boundary between Earth’s crust and mantle—called “Moho” for short—and sample it for the first time, to learn more about how Earth’s crust was formed.(Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)