Revised oceanic molybdenum isotope budget from deep-sea pelagic sediments.

ABSTRACT: Molybdenum isotopes serve as critical proxies for reconstructing ancient ocean oxygenation, yet the modern oceanic Mo isotopic budget remains incompletely understood. Deep-sea pelagic sediments enriched in Fe-Mn (hydro)oxides represent a major oxic sink, but their authigenic Mo isotopic composition is poorly constrained. Here, we show Mo isotope data from Pacific deep-sea sediment cores revealing systematic depth-dependent δ⁹⁸Mo enrichment from ‒0.55‰ to 0.19‰, controlled by Fe-Mn cycling during early diagenesis. Combined with existing datasets, we calculate a revised authigenic oxic Mo flux of 1.52 × 10⁸ mol yr⁻¹ with δ⁹⁸Mo = ‒0.09 ± 0.23‰-more than double previous estimates and ~0.6‰ heavier than Fe-Mn crusts. These findings necessitate recalibration of the global M

SUBMITTER: Wang Z 

PROVIDER: S-EPMC12627635 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature