Calculated mineral equilibria for eclogites in CaO-Na2O-FeO-MgO-Al2O3-SiO2-H2O: application to the Pouebo Terrane, Pam Peninsula, New Caledonia

The high-P, medium-T Pouebo terrane of the Pam Peninsula, northern New Cale donia includes barroisite- and glaucophane-bearing eclogite and variably re hydrated equivalents. The metamorphic evolution of the Pouebo terrane is in ferred from calculated P-T and P-T-X-H2O pseudosections for bulk compositio ns appropriate to these rocks in the model system CaO-Na2O-FeO-MgO-Al2O3-Si O2-H2O. The eclogites experienced a clockwise P-T path that reached P appro ximate to 19 kbar and T approximate to 600 degrees C. The eclogitic mineral assemblages are preserved because reaction consequent upon decompression c onsumed the rocks' fluid. Extensive reaction occurred only in rocks with fl uid influx during decompression of the Pouebo terrane.