Enrichment mechanisms of rare earth elements in marine hydrogenic ferromanganese crusts
Jiang, X. J.
Lin, X. H.
Guo, W. D.
- 海洋环境－已发表论文 
A series of selective extraction experiments were conducted on marine hydrogenic ferromanganese crusts from the seamount near the Line Island to investigate the distribution of rare earth elements (REEs) and the mechanisms of combination between REEs and the hydrogenic ferromanganese crusts. The enrichment of REEs in hydrogenic ferromanganese crusts is attributed mainly to the mineral or oxide/hydroxide of the crust rather than the growth environment. The REEs are present mainly in amorphous ferric oxide/hydroxide rather than in delta-MnO(2). Amorphous ferric oxide/hydroxide preferentially combines free REE(3+), while delta-MnO(2) combines the REE-carbonate complexes in modern seawater. The REEs in seawater are combined more strongly with amorphous ferric oxide/hydroxides than with delta-MnO(2). The positive Ce anomaly in hydrogenic ferromanganese crusts results from the oxidation of soluble Ce(3+) to insoluble Ce(4+) by the actively soluble oxygen of the bottom current rather than by the oxidation of delta-MnO(2).