The regional migmatites in the Yunkai Block were formed under low\|pressure metamorphism. The majority of their protolith are biotite\|rich peraluminous gneisses. Detailed field observations, and studies of petrology, spatial distribution of minerals and geochemistry suggest that the leucosomes were derived from anatexis. The single grain zircon U\|Pb dating data indicate that a pulse of migmatization occurred at 394～449 Ma and may have resulted from the large\|scale Caledonian magmatism in the Yunkai Block.
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