image: Photograph of a diamond-anvil cell (approximately 5 mm across). Between the tips of these gem diamonds, heating experiments on deep-mantle minerals were carried out at conditions of 660 km depth, or about 400 miles below the surface. The experiments revealed a dehydration reaction of the mineral ringwoodite, which can cause melting of the rock deep in the mantle. Evidence for that reaction was then observed in seismic waves passing through 660 km beneath North America, implying that a large amount of water (in the form of hydrated minerals) can reach these great depths through plate tectonics. This image relates to a paper that appeared in the 13 June, 2014, issue of Science, published by AAAS. The paper, by B. Schmandt at the University of New Mexico in Albuquerque, N.M., and colleagues was titled, "Dehydration melting at the top of the lower mantle." view more
Credit: [Credit: Steve Jacobsen / Northwestern University]