Cerium isotopes unveil hydrogenetic Fe-Mn encrustation occurring throughout from the oxygen minimum zone to the deep pacific.

profiles in seawater and crusts across the OMZ in the Northwest Pacific Ocean, which are closely linked with the ocean Mn cycle. We further quantify a close association of Ce with Mn oxides in Fe-Mn crusts and Ce isotope fractionation between crusts and ambient seawater, bridging marine Mn and Ce cycles. These results support a revised model in which Mn oxide precipitation could initiate within the OMZ and persist into the deep ocean.