Subducted Oceanic Crusts (IMAGE) Ehime University Caption A schematic image of subducted oceanic crust inferred from this study. Basalt and harzburgite layers of the oceanic crust accumulate beneath and above the 660 km discontinuity, respectively. Credit Ehime University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.