Rocks Do Tell Tales

A rock sample, collected from the Central Indian Ridge, a mountain chain running through the Indian Ocean, sparkles with information. It’s channel is lined with a fine-grained mineral called chalcopyrite as well as a white mineral called anhydrite. Researchers on board the research vessel Knorr took the sample in 2001 from a black smoker chimney, one of many structures that can form at high-temperature, seafloor hydrothermal systems. Scientists study them to learn about tectonic processes, and they are of increasing commercial interest for their production of minerals. (Photo by Amy Nevala, Woods Hole Oceanographic Institution)