Economic and Environmental Geology

Fig. 3.

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Fig. 3. Conceptual model of each genetic types of REE-bearing coal deposits. Genetic types can largely be classified by their REE input stages; (1) Syngenetic stage: terrigenous and tuffaceous types. REE are originated from weathered bauxite or volcanic ash, leaching after their deposition. Detrital and authigenic REE minerals occur simultaneously. (2) Epigenetic stage: infiltrational and hydrothermal types. When granitic intrusions are near coal deposits, REE are derived by hydrothermal fluid and forms authigenic minerals and organic compounds.
Econ. Environ. Geol. 2022;55:241-59
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