Study of mineral exsolution on the Songduo eclogites in Tibet

A lot exsolution structures have been observed in the Songduo eclogites,southern Tibet.EDS analyzing in the EPMA shows that the exsolutions in garnet are rutile,and the exsolutions in omphacite are a K-rich mineral and quartz.The calculation of the garnet-omphacite-phengite geobarothermometer shows that the peak-metamorphic P-T conditions of the Songduo eclogites are close to the transformation line between quartz-coesite.Thus,the exsolutions of minerals indicate that the Songduo eclogites likely experienced UHP metamorphism,which provides an important evidence for formation P-T conditions of the Songduo eclogites.