Figure 8
Cartoon illustrating the fluxing model.
Subduction releases high-Si fluids, which leached Fe and Mg from the mantle wedge through serpentinisation at temperatures lower than 720°C44 and hydrothermal alteration. These fluids then react with a carbonatite pluton, leaching REE, Nb and Th out of the carbonatite. Finally, the ore-forming fluids ascend along fractures and react with H8 carbonates of the Bayan Obo Group, forming the giant REE, Nb, Th and Fe deposit.
