Superionic iron hydride shapes ultralow-velocity zones at Earth's core-mantle boundary.

ABSTRACT: Seismological studies have exposed numerous ultralow velocity zones (ULVZs) exhibiting extraordinary physical attributes at Earth's core-mantle boundary, yet their compositions and origins remain controversial. Water-iron reaction can generate unique phases under lowermost-mantle conditions and likely plays a crucial role in forming ULVZs. Through first-principles molecular dynamic simulations with machine learning techniques, we determine that iron hydride, the product of water-iron reaction, is stable as a superionic phase at the core-mantle boundary. This superionic iron hydride has much slower velocities and a higher density than the ambient mantle under lowermost-mantle conditions. Accumulation of iron hydride, created through either a chemical reaction between subducted water and iro

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC11363269 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature