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Rock Grab

March 7, 2017

A pilot inside the submersible Alvin uses one of the vehicle’s manipulator arms to pick up some unusual geological samples: popping rocks. WHOI scientists collected them in 2016, on this expedition to the Mid-Atlantic Ridge funded by the National Science Foundation. Gases from deep inside the Earth are trapped in tiny glass vesicles inside popping rocks. Once the rocks are brought to the surface, they are no longer under deep-sea pressure, and their gases escape with a characteristic “pop!” Scientists are analyzing these gases for clues to the composition and evolution of Earth’s mantle.(Mark Kurz, WHOI, Eric Mittelstaedt, Univ. of Idaho/NSF/HOV Alvin 2016 ©Woods Hole Oceanographic Institution )