Water-rich incipient melt of the deep upper mantle indicates locally preserved low-velocity zones above the 410 km discontinuity.

ABSTRACT: Seismic low-velocity layers (LVLs), frequently attributed to hydrous-silicate melts, are detected globally but exhibit lateral discontinuities. Geophysical and laboratory studies of water content in the mantle transition zone (MTZ) and upper mantle solubility limits suggest these layers likely form through global dehydration melting near the 410 km discontinuity (D410). A key hypothesis posits that melts form globally but are preserved only where melt stability permits retention. However, challenges in quenching melts into glass or fine-grained crystals at mantle pressures have precluded precise determination of melt composition, fueling debates over the mechanisms governing LVLs' sporadic distribution. Here, we developed a fast-quenching high-pressure cell assembly to synthesize hydrous g

SUBMITTER: Xie L 

PROVIDER: S-EPMC12167984 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature