The discovery of eclogite-high-pressure granulite association from Hainan Island, South China

An eclogite-high-pressure (HP) granulite association were firstly discovered in the Mulantou area, northeastern Hainan Island, South China. The HP rocks occur in the coastal intertidal zone, and consist mainly of garnet, omphacite, hornblende, quartz and rutile, with or without zoisite or plagioclase. Peak p-t conditions of the rocks obtained by conventional geothermobarometers are about 800~850° C and >1.5GPa. U-Pb zircon dating yields metamorphic ages of about 340~300Ma. The occurrence of HP granulite-eclogite association is of great significance for understanding the tectonic affinity of Hainan Island and the tectonic evolution of the eastern Paleo-Tethys.