New mantle model gets the water out

Between our planet’s crust and its core lies the mantle, a realm where solid rock oozes under pressures millions of times as great as that exerted by the atmosphere. Although some scientists hold that the entire mantle gradually mixes, others suspect that the mantle’s deeper rock–and the trace elements it contains–typically doesn’t get too close to Earth’s crust, says geophysicist David Bercovici of Yale University.