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Abstract: Petrography, mineral chemistry and pressure–temperature (P–T) estimates were carried out for the eclogite from the South Altyn in NW China. The results suggest three stages of metamorphism: an ultra-high pressure (UHP) eclogite-facies metamorphism at 717–871°C and ≥2.8GPa, a high pressure (HP) granulite-facies metamorphism at 624–789°C and 1.42–1.52GPa, and an amphibolite-facies metamorphism at 597–728°C and 0.99–1.17GPa. Cathodoluminescence investigation revealed that zircons from the retrograde eclogite display a distinct core-rim structure. Cores are grey-white luminescent and contain mineral inclusions of Garnet+Omphacite+Rutile+Quartz, suggesting eclogite-facies metamorphic origin. The rims are dark grey luminescent and contain Garnet+Clinopyroxene+Pagioclase inclusions, forming at HP granulite-facies conditions. A few residual zircon grains with mottled internal structure also occur as the metamorphic cores. LA-ICPMS zircon U–Pb dating yielded three discrete age groups: (1) a Neoproterozoic protolith age of 752±7Ma for the residual grains, (2) an eclogite-facies metamorphic age of 500±7Ma for the metamorphic cores, and (3) a HP granulite-facies retrograde age of 455±2Ma for the rims. These ages indicate that the protolith of the Altyn eclogite probably formed in response to breakup of the Rodinia supercontinent during the Neoproterozoic; it was subjected to continental deep subduction and UHP metamorphism during early Paleozoic (~500Ma) and subsequently underwent two stages of retrograde metamorphism during exhumation. The petrological and geochronological data suggest a clockwise P–T–t path for the UHP eclogite. According to pressures and ages for the peak UHP eclogite-facies and the retrograde HP granulite-facies metamorphism, an exhumation rate of 1.2mm/yr was estimated for the eclogite, which is considerably slower than that of some UHP rocks from other UHP terranes (>5mm/yr). While the peak metamorphic age of 500Ma is consistent with previous dates of 480–504Ma, it is 40–60Myr older than the HP/UHP metamorphic ages of 420–461Ma for UHP eclogites in North Qaidam. The retrograde metamorphic age is 455±2Ma for the Altyn eclogite, which is 30–55Myr older than ~400–425Ma for the North Qaidam eclogites. These age differences suggest that the South Altyn and North Qaidam eclogites do not belong to the same HP/UHP metamorphic zone. [Copyright &y& Elsevier]