Rare earth elements in phosphate-ferromanganese crusts on Pacific seamounts

Based on publications devoted to the composition of P-rich ferromanganese crusts on Pacific seamounts, relationships between the REE distribution in the crusts and the contents of phosphates and Fe-Mn hydroxides therein are considered. It is shown that REEs in the crusts are related to all three mineral phases and their contents are variable. In general, the REEs show weak correlations with P, Mn, and Fe in different varieties of ore crust. Average REE contents are comparable in samples with the maximal and minimal phosphorus contents, suggesting irregularity of REE distribution in the phosphates and ferromanganese phases. This fact is consistent with data on the presence of natural REE minerals in the phosphates.