Deep inside the earth, seismic observations reveal that three distinct structures make up the boundary between the earth's metallic core and overlying silicate mantle at a depth of about 2,900 kilometers—an area whose composition is key to understanding the evolution and dynamics of our planet. These structures include remnants of subducted plates that originated near the earth's surface, ultralow-velocity zones believed to be enriched in iron, and large dense provinces of unknown composition and mineralogy. A team led by Caltech's Jennifer Jackson, professor of mineral physics has new evidence for the origin of these features that occur at the core-mantle boundary.

In addition to the pressure-volume-temperature diffraction experiments conducted at GSECARS beamline 13-ID-D, this work utilized two different COMPRES resources: the gas-loading system at GSECARS and the unique capabilities at sector 3 to constrain the site-specific behavior of iron in bridgmanite.

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