Vertical depletion of ophiolitic mantle reflects melt focusing and interaction in sub-spreading-center asthenosphere.

ABSTRACT: Decompressional melting of asthenosphere under spreading centers has been accepted to produce oceanic lithospheric mantle with vertical compositional variations, but these gradients are much smaller than those observed from ophiolites, which clearly require additional causes. Here we conduct high-density sampling and whole-rock and mineral analyses of peridotites across a Tibetan ophiolitic mantle section (~2 km thick), which shows a primary upward depletion (~12% difference) and local more-depleted anomalies. Thermodynamic modeling demonstrates that these features cannot be produced by decompressional melting or proportional compression of residual mantle, but can be explained by melt-peridotite reaction with lateral melt/rock ratio variations in an upwelling asthenospheric column, produc

SUBMITTER: Xiong Q 

PROVIDER: S-EPMC9663536 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature