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The compositional zoning of the garnet in a strongly deformed eclogite from Raobazhaifoliated peridotite has been recognized. The CaO concentrations of the garnet are decreased fromthe core to the rim, while its MnO concentrations are increased, suggesting the retrograde origin ofsuch CaO-MnO zoning. The tie line of garnet+omphacite from this eclogite gives a Sm-Nd ageof (187±5) Ma, which is less significant than the Sm-Nd ages of (221±5)-(228±3) Ma and (210±6)-(214±6) Ma for ultrahigh-pressure eclogites in the southern Dabie zone and in the northernDabie zone, respectively. This younger Sm-Nd age could result from the ~(143)Nd/~(144)Nd ratio decreaseof the retrograde zone in the garnet. The δ~(80)O values of the garnet and omphacite show that theirfractionation values are less than the equilibrium fractionation value between the garnet and om-phacite at 500-900℃, which suggests an oxygen isotopic disequilibrium between them.
The compositional zoning of the garnet in a strongly deformed eclogite from Raobazhaifoliated peridotite has been recognized. The CaO concentrations of the garnet are decreased from the core to the rim, while its MnO concentrations are increased, suggesting the retrograde origin ofsuch CaO-MnO zoning. The The tie line of garnet + omphacite from this eclogite gives a Sm-Nd age of (187 ± 5) Ma, which is less significant than the Sm-Nd ages of (221 ± 5) - (228 ± 3) Ma and (210 ± 6 ) - (214 ± 6) Ma for ultrahigh-pressure eclogites in the southern Dabie zone and in the northern Dabie zone, respectively. This younger Sm-Nd age could result from ~ (143) Nd / ~ 144 Nd ratio decrease of the retrograde zone in the garnet. The δ ~ (80) O values of the garnet and omphacite show that their fractionation values are less than the equilibrium fractionation value between the garnet and om-phacite at 500-900 ° C, which suggests an oxygen isotopic disequilibrium between them