Abstract: Water, incorporated into minerals and melts at the very high pressure and temperature conditions of Earth’s deep mantle may constitute the planet’s largest geochemical reservoir of H2O. Hidden from view, the mantle transition zone (410- to 660-km depth) may contain several oceans worth of water. At the atomic scale, hydration modifies the structure and physical properties of minerals through associated defects. At mesoscopic scales, water influences diffusion, rheology, and lattice-preferred orientation. At geophysical scales, water cycling through the solid mantle plays a critical role in melt generation and plate tectonics and may have acted to buffer the volume of Earth’s oceans over geologic time. This talk will focus on recent laboratory experiments, naturally occurring inclusions in diamond, and seismological observations that reveal clues about the distribution and origin of water in our habitable planet.
Bio: Steve Jacobsen is a professor of earth and planetary sciences at Northwestern University, where he frequents the Advanced Photon Source to use synchrotron radiation for exploring the structure and dynamics of Earth and planetary materials at extreme conditions. He received his Ph.D. from the University of Colorado.