(Table 1) Rare earth element contents in basalts and glasses of DSDP Legs 45 and 51

When the alteration is well-marked, the REE distribution in altered glasses shows an enrichment in light rare-earths relative to the fresh glass. In particular, Ce is selectively enriched in palagonitized glasses that comprise, besides polymetallic nodules, another phase liable to explain the Ce depletion in seawater.

Taking in account these processes of submarine weathering of the oceanic crust, a geochemical balance of Ce between authigenic phases of the marine environment is attempted.